G2Cdb::Gene report

Gene id
G00002235
Gene symbol
CTNNB1 (HGNC)
Species
Homo sapiens
Description
catenin (cadherin-associated protein), beta 1, 88kDa
Orthologue
G00000986 (Mus musculus)

Databases (8)

Gene
ENSG00000168036 (Ensembl human gene)
1499 (Entrez Gene)
38 (G2Cdb plasticity & disease)
CTNNB1 (GeneCards)
Literature
116806 (OMIM)
Marker Symbol
HGNC:2514 (HGNC)
Protein Expression
108 (human protein atlas)
Protein Sequence
P35222 (UniProt)

Synonyms (1)

  • beta-catenin

Diseases (34)

Disease Nervous effect Mutations Found Literature Mutations Type Genetic association?
D00000111: Familial adenomatous polyposis N Y (10398435) Microinsertion (MI) N
D00000111: Familial adenomatous polyposis N Y (10398435) Deletion (D) N
D00000111: Familial adenomatous polyposis N Y (14691304) No mutation found (N) N
D00000110: Extracolonic tumours in familiar adenomatous polyposis N Y (15287021) No mutation found (N) N
D00000064: Urothelial carcinoma N Y (11956582) No mutation found (N) N
D00000044: Endometrial cancer N Y (10671680) Microinsertion (MI) Y
D00000057: Prostate cancer N Y (11921277) Single nucleotide polymorphism (SNP) Y
D00000057: Prostate cancer N Y (9635571) Microinsertion (MI) Y
D00000022: Colorectal cancer N Y (9294210) Deletion (D) Y
D00000022: Colorectal cancer N Y (9294210) Single nucleotide polymorphism (SNP) Y
D00000022: Colorectal cancer N Y (11217439) Deletion (D) Y
D00000022: Colorectal cancer N Y (11217439) Microinsertion (MI) Y
D00000022: Colorectal cancer N Y (9515795) Unknown (?) Y
D00000022: Colorectal cancer N Y (12379157) No mutation found (N) N
D00000022: Colorectal cancer N Y (10416591) Single nucleotide polymorphism (SNP) Y
D00000022: Colorectal cancer N Y (10416591) Deletion (D) Y
D00000045: Endometrial carcinoma N Y (10416591) Single nucleotide polymorphism (SNP) Y
D00000045: Endometrial carcinoma N Y (10416591) Deletion (D) Y
D00000023: Colorectal carcinoma N Y (12408524) Unknown (?) N
D00000024: Rectal carcinoma N Y (11454429) No mutation found (N) N
D00000025: Hepatoblastoma N Y (10398436) Single nucleotide polymorphism (SNP) Y
D00000027: Hepatocellular carcinoma N Y (11429783) Single nucleotide polymorphism (SNP) Y
D00000027: Hepatocellular carcinoma N Y (11429783) Deletion (D) Y
D00000106: Infiltrating lobular breast carcinoma N Y (12800196) No mutation found (N) N
D00000046: Uterine endometrioid carcinoma N Y (11048799) Microinsertion (MI) Y
D00000046: Uterine endometrioid carcinoma N Y (11048799) Deletion (D) Y
D00000054: Ovarian epithelial tumour N Y (10876313) Microinsertion (MI) Y
D00000052: Ovarian endometrioid carcinoma N Y (9537226) Unknown (?) Y
D00000051: Ovarian endometrioid adenocarcinoma N Y (11719457) Microinsertion (MI) Y
D00000053: Ovarian endometrioid tumour N Y (10417756) Microinsertion (MI) Y
D00000109: Colorectal adenoma N Y (12737446) Unknown (?) ?
D00000113: Pilomatricoma N Y (11472567) Unknown (?) Y
D00000113: Pilomatricoma N Y (10192393) Single nucleotide polymorphism (SNP) Y
D00000043: Cervical cancer N Y (12883680) No mutation found (N) N
D00000033: Cutaneous melanoma N Y (11950921) Unknown (?) N
D00000032: Cutaneous malignant melanoma N Y (11351304) Single nucleotide polymorphism (SNP) ?
D00000074: Medulloblastoma N Y (12209999) Single nucleotide polymorphism (SNP) ?
D00000035: Malignant melanoma N Y (12124804) Single nucleotide polymorphism (SNP) Y
D00000035: Malignant melanoma N Y (12124804) Deletion (D) Y
D00000035: Malignant melanoma N Y (15133491) Single nucleotide polymorphism (SNP) Y
D00000008: Melanoma N Y (9065403) Microinsertion (MI) Y
D00000008: Melanoma N Y (11930117) Deletion (D) N
D00000120: Sporadic desmoid tumour N Y (10655994) Single nucleotide polymorphism (SNP) Y
D00000077: Primitive neuroectodermal tumour N Y (11433413) Single nucleotide polymorphism (SNP) Y
D00000082: Thyroid carcinoma N Y (11238046) Microinsertion (MI) Y
D00000080: Papillary thyroid carcinoma N Y (12474227) Unknown (?) Y
D00000002: Adenocarcinoma N Y (11170292) Microinsertion (MI) Y
D00000045: Endometrial carcinoma N Y (11957146) Repeat polymorphism (RP) Y
D00000028: Lung cancer N Y (11464291) Single nucleotide polymorphism (SNP) Y
D00000028: Lung cancer N Y (11464291) Deletion (D) Y
D00000038: Malignant mesothelioma N Y (11464291) Single nucleotide polymorphism (SNP) Y
D00000038: Malignant mesothelioma N Y (11464291) Deletion (D) Y
D00000084: Parathyroid adenoma N Y (17284619) No mutation found (N) N
D00000321: Cancer N Y (17258725) No mutation found (N) N

References

  • Absence of stabilizing mutations of beta-catenin encoded by CTNNB1 exon 3 in a large series of sporadic parathyroid adenomas.

    Costa-Guda J and Arnold A

    Center for Molecular Medicine, University of Connecticut School of Medicine, 263 Farmington Avenue, Farmington, Connecticut 06030-3101, USA.

    Context: The molecular mechanisms underlying the pathogenesis of sporadic parathyroid adenomas are incompletely understood. Dysfunction of the Wnt signaling pathway is an established pathogenetic contributor to human tumorigenesis and, recently, the role of stabilizing mutations in beta-catenin, a cause of abnormal Wnt signaling, has been examined in parathyroid tumors with conflicting results.

    Objective: The objective of the present study was to determine the frequency of stabilizing mutations in exon 3 of CTNNB1, encoding beta-catenin, in a large series of parathyroid adenomas.

    Ninety-seven sporadic parathyroid adenomas were examined for mutations in exon 3 of CTNNB1 by direct DNA sequencing.

    Results: No mutations were identified in any of the adenomas.

    Conclusions: The absence of stabilizing mutations of beta-catenin, including the previously reported S37A, encoded in CTNNB1 exon 3 among 97 tumors suggests that such mutations contribute rarely if at all to the development of sporadic parathyroid adenomas. A primary role for abnormal Wnt signaling in parathyroid tumor formation remains to be established.

    Funded by: NIDCR NIH HHS: 5T32-DE07302

    The Journal of clinical endocrinology and metabolism 2007;92;4;1564-6

  • Homozygous PMS2 deletion causes a severe colorectal cancer and multiple adenoma phenotype without extraintestinal cancer.

    Will O, Carvajal-Carmona LG, Gorman P, Howarth KM, Jones AM, Polanco-Echeverry GM, Chinaleong JA, Günther T, Silver A, Clark SK and Tomlinson I

    Molecular and Population Genetics Laboratory, London Research Institute, Cancer Research, London, UK.

    We report a patient of Indian descent with parental consanguinity, who developed 10 carcinomas and 35 adenomatous polyps at age 23 and duodenal adenocarcinoma at age 25. He also had dysmorphic features, mental retardation, and café-au-lait spots but no brain tumor. We aimed to establish his molecular diagnosis.

    Methods: Germ-line screening for APC and MYH/MUTYH mutations was normal as was immunohistochemistry for MLH1 and MSH2 proteins. Investigation by array-comparative genomic hybridization revealed deletion of a small region on chromosome 7. Using polymerase chain reaction, this region was refined to a 400-kilobase deletion, which included exons 9-15 of the PMS2 gene, and all coding regions of oncomodulin, TRIAD3, and FSCN1.

    Results: The deletion was confirmed as homozygous, and both parents were carriers. Immunohistochemistry showed absent PMS2 expression in all tumors and normal tissue. Most tumors showed microsatellite instability, more marked at dinucleotide than mononucleotide repeats. The tumors harbored no somatic mutations in APC, BRAF, AXIN2, or beta-catenin, but KRAS2 and TGFBR2 mutations were found.

    Conclusions: Our patient represents a novel phenotype for homozygous PMS2 mutation and perhaps the most severe colorectal cancer phenotype-in terms of numbers of malignancies at an early age-described to date. PMS2 mutations-and perhaps other homozygous mismatch repair mutations-should be considered in any patient presenting with multiple gastrointestinal tumors, since our patient could not be distinguished clinically from cases with attenuated familial adenomatous polyposis or MUTYH-associated polyposis.

    Gastroenterology 2007;132;2;527-30

  • Analysis of somatic APC mutations in rare extracolonic tumors of patients with familial adenomatous polyposis coli.

    Bläker H, Sutter C, Kadmon M, Otto HF, Von Knebel-Doeberitz M, Gebert J and Helmke BM

    Institute of Pathology, University of Heidelberg, Heidelberg, Germany. Hendrik_Blaeker@med.uni-heidelberg.de

    Patients with familial adenomatous polyposis coli (FAP) carry heterozygous mutations of the APC gene. At a young age, these patients develop multiple colorectal adenomas that consistently display a second somatic mutation in the remaining APC wild-type allele. Inactivation of APC leads to impaired degradation of beta-catenin, thereby promoting continuous cell-cycle progression. The role of APC inactivation in rare extracolonic tumors of FAP patients has not been characterized sufficiently. Among tissue specimen from 174 patients with known APC germ-line mutations, we identified 8 tumors infrequently seen in FAP. To investigate the pathogenic role of APC pathway deregulation in these lesions, they were analyzed for second-hit somatic mutations in the mutational cluster region of the APC gene. Immunohistochemistry was performed to compare the expression pattern of beta-catenin to the mutational status of the APC gene. Exon 3 of the beta-catenin gene (CTNNB1) was analyzed for activating mutations to investigate alternative mechanisms of elevated beta-catenin concentration. Although CTNNB1 mutations were not observed, second somatic APC mutations were found in 4 of the 8 tumors: a uterine adenocarcinoma, a hepatocellular adenoma, an adrenocortical adenoma, and an epidermal cyst. These tumors showed an elevated concentration of beta-catenin. No APC mutations were seen in focal nodular hyperplasia of the liver, angiofibrolipoma, and seborrheic wart. This is the first study reporting second somatic APC mutations in FAP-associated uterine adenocarcinoma and epidermal cysts. Furthermore, our data strengthen a role for impaired APC function in the pathogenesis of adrenal and hepatic neoplasms in FAP patients.

    Genes, chromosomes & cancer 2004;41;2;93-8

  • Genetic and epigenetic alterations of the APC gene in malignant melanoma.

    Worm J, Christensen C, Grønbaek K, Tulchinsky E and Guldberg P

    Institute of Cancer Biology, Danish Cancer Society, Strandboulevarden 49, DK-2100 Copenhagen, Denmark.

    High levels of beta-catenin and activating mutations in the beta-catenin gene (CTNNB1) have been demonstrated in malignant melanomas, implicating dysregulated Wnt signalling in the pathogenesis of this malignancy. We systematically examined melanoma cell lines for activating CTNNB1 mutations as well as genetic and epigenetic alterations of the adenomatous polyposis coli gene (APC), another key component of the Wnt signalling transduction pathway. Of 40 cell lines tested, one carried a truncating APC mutation and loss of the corresponding wild-type allele, and one carried a CTNNB1 missense mutation. Hypermethylation of APC promoter 1A was present in five of the cell lines (13%) and in nine of 54 melanoma biopsies (17%). Cells with truncating APC or activating CTNNB1 mutations showed increased transcription from endogenous and ectopic beta-catenin/T-cell factor (Tcf)-responsive target genes, consistent with the known effects of these alterations on beta-catenin stability and Tcf transactivation. In contrast, cell lines with APC promoter 1A hypermethylation did not show increased Wnt signalling, probably due to residual APC activity expressed from promoter 1B. Suppression of APC transcripts in melanoma cells by stable expression of short hairpin RNAs led to a Wnt signalling-independent increase in cell proliferation, but also reduced the invasive growth in collagen type I. Collectively, our data suggest that the tumour-suppressive function of APC in melanocytic cells is dose dependent. We propose that epigenetic silencing of promoter 1A may contribute to the development of malignant melanoma by reducing the expression of APC to a level that promotes cell proliferation without compromising the invasive capacity.

    Oncogene 2004;23;30;5215-26

  • APC haploinsufficiency, but not CTNNB1 or CDH1 gene mutations, accounts for a fraction of familial adenomatous polyposis patients without APC truncating mutations.

    Venesio T, Balsamo A, Rondo-Spaudo M, Varesco L, Risio M and Ranzani GN

    Unit of Pathology, Institute for Cancer Research and Treatment, Candiolo-Torino, Genova, Italy.

    Familial adenomatous polyposis (FAP) is an autosomal dominant condition characterized by the development of hundreds to thousands of colorectal adenomatous polyps. In addition to the classic form, there is also attenuated polyposis (attenuated adenomatous polyposis coli; AAPC), which is characterized by a milder phenotype. FAP/AAPC is caused by germline mutations in the adenomatous polyposis coli (APC) gene. Very recently, germline mutations in the base-excision repair gene MYH have been associated with recessive inheritance of multiple colorectal adenomas in a subset of patients. APC pathogenic alterations are mostly (>95%) represented by frameshift or nonsense mutations leading to the synthesis of a truncated protein. We identified 20 APC truncating mutation carriers out of 30 FAP/AAPC patients from different Italian kindreds. In the remaining 10 patients, we searched for alterations other than truncating mutations by enzymatic mutation detection, real-time quantitative RT-PCR, and genotyping of polymorphic markers encompassing the APC locus. Moreover, to assess whether mutations of genes interacting with APC can substitute or act in association with APC alterations, we sequenced both CTNNB1 (beta-catenin) and CDH1 (E-cadherin) genes. No CTNNB1 or CDH1 mutations were found. On the contrary, four patients showed a reduced APC gene expression compared with healthy subjects. In three of the four cases, genotyping results were compatible with a constitutive allelic deletion. In one case this conclusion was confirmed by haplotype segregation analysis. Our results support the notion that FAP/AAPC can result from APC constitutive haploinsufficiency, with gene deletion being a possible cause of reduced gene expression.

    Laboratory investigation; a journal of technical methods and pathology 2003;83;12;1859-66

  • Mutation analysis of CTNNB1 (beta-catenin) and AXIN1, the components of Wnt pathway, in cervical carcinomas.

    Su TH, Chang JG, Yeh KT, Lin TH, Lee TP, Chen JC and Lin CC

    Department of Molecular Medicine, China Medical College Hospital, Taichung, Taiwan.

    The components of the Wnt-signaling pathway are mutated in tumors, but the relationship between these components and cervical cancer has not been elucidated. In this study, we used immunohistochemistry, single strand confirmation polymorphism (SSCP) and direct sequencing methods to analyze the mutation and protein expressions of both CTNNB1 and AXIN1 in cervical cancer. Among the 30 tested cervical cancers, no mutation of CTNNB1 but 3 polymorphisms were found. Mutation analysis of AXIN1 revealed that one specimen had a heterozygous mutation at codon 740 (GCC right curved arrow ACC) and six polymorphisms were also found. Immunohistochemistry showed no relationship between the protein expression patterns and mutation of AXIN1 and CTNNB1. Mutations of CTNNB1 may not be a factor, whereas mutations of AXIN1 may play a limited role in tumorigenesis of cervical cancer. In addition, aberrant expression patterns are not mutation related, so that other factors may be responsible for these changes.

    Oncology reports 2003;10;5;1195-200

  • Epigenetic and genetic alterations of APC and CDH1 genes in lobular breast cancer: relationships with abnormal E-cadherin and catenin expression and microsatellite instability.

    Sarrió D, Moreno-Bueno G, Hardisson D, Sánchez-Estévez C, Guo M, Herman JG, Gamallo C, Esteller M and Palacios J

    Laboratory of Breast and Gynecological Cancer, Molecular Pathology Program, Centro Nacional de Investigaciones Oncológicas, Madrid, Spain.

    The causes and functional consequences of E-cadherin (E-CD) loss in breast cancer are poorly understood. E-CD loss might act in concert with alterations in the APC/beta-catenin pathway to permit oncogenic beta-catenin signaling. To test this hypothesis, we have analyzed the presence of genetic and epigenetic alterations affecting E-CD (CDH1), APC and beta-catenin (CTNNB1) genes and the immunohistochemical expression of E-CD, beta- and gamma-catenin in a series of 46 infiltrating lobular breast carcinomas (ILCs). Since 80% of ILCs featured complete loss of E-CD expression, we analyzed the molecular alterations responsible for E-CD inactivation in these tumors. We found that 10 of 46 (22%) cases harbored mutations in CDH1, including 1 case with 2 different mutations (1 of which was germline). CDH1 was also inactivated by loss of heterozygosity (LOH; 30/41, 73%) and promoter hypermethylation (19/46, 41%). Interestingly, LOH and mutations were also detected in the corresponding in situ lesions of the ILCs, implying that these alterations are early events in lobular cancer tumorogenesis. Additionally, the presence of a polymorphism in the CDH1 promoter was found to be inversely correlated with CDH1 mutations, but not with E-CD levels. We next examined whether alterations in the APC/beta-catenin pathway also occurred in the same series of ILCs. Although no CTNNB1 or APC mutations were detected, promoter methylation (25/46, 52%) and LOH (7/30, 23%) of APC were found. Moreover, methylation of APC and CDH1 occurred concordantly. However, beta- and gamma-catenin were severely reduced or absent in 90% of these tumors, implying that alterations in CDH1 and APC genes do not promote beta-catenin accumulation in ILC. These molecular alterations were not associated with microsatellite instability. In summary, several different mechanisms (mutations, LOH, methylation) are involved in the frequent CDH1 inactivation in invasive and in situ lobular breast cancer. The same tumors also show genetic and epigenetic alterations of APC gene. However, altered CDH1 and APC genes do not promote beta-catenin accumulation in this tumor type.

    International journal of cancer 2003;106;2;208-15

  • Genetic and protein markers related to in situ growth and multiplicity in small sporadic colorectal adenomas.

    Løvig T, Thorstensen L, Hofstad B, Andersen SN, Clausen OP, Vatn M, Lothe RA and Rognum TO

    Institute of Forensic Medicine, University of Oslo, The National Hospital, NO-0027 Oslo, Norway. tone.lovig@labmed.uio.no

    Background: Some early genetic events in the development of colorectal adenomas are known, but their relationship to in vivo growth characteristics is uncertain. This study compared in situ size changes and other clinicopathological variables with selected genetic and protein markers.

    Methods: 56 adenomas (< or = 10 mm) from 39 patients were analysed for APC, CTNNB1 and K-ras mutations, allelic imbalance on 1p and 18q, microsatellite instability and immunohistochemical expression of HLA-DR, BAX, BCL-2 and Ki-67. For 42 of the adenomas, in situ growth was measured over 3 years. The total number of polyps in each patient was recorded.

    Results: K-ras was mutated in 8/56 adenomas. None of the regressing adenomas revealed such mutations, compared to 20% in those that maintained or increased their size. Multivariate linear regression analysis showed that tumour growth was higher in females compared to males, and was even higher in the presence of a K-ras mutation. APC mutations were found in 37/56 adenomas. CTNNB1 mutations were found in 2/19 adenomas without APC mutation. Deletions of 1p were found in 12/56 adenomas and, seemingly, most frequent in patients with few tumours. The most frequently expressed protein was BAX (33/41), but neither this nor the other proteins showed associations with an in situ growth pattern.

    Conclusion: The multivariate linear regression model showed that patient gender and the presence of K-ras mutation had significant effects on tumour growth. The lack of the proliferative stimulus resulting from a K-ras mutation may contribute to the process of adenoma regression.

    Scandinavian journal of gastroenterology 2003;38;3;298-306

  • Cribriform-morular variant of papillary thyroid carcinoma: a pathological and molecular genetic study with evidence of frequent somatic mutations in exon 3 of the beta-catenin gene.

    Xu B, Yoshimoto K, Miyauchi A, Kuma S, Mizusawa N, Hirokawa M and Sano T

    Department of Pathology, University of Tokushima School of Medicine, Tokushima 770-8503, Japan. xubing@basic.med.tokushima-u.ac.jp

    The cribriform-morular variant (C-MV), an unusual and peculiar subtype of papillary thyroid carcinoma (PTC), has been observed frequently in familial adenomatous polyposis (FAP)-associated thyroid carcinoma and also in sporadic thyroid carcinoma. In this paper, five young women with the C-MV of PTC, aged 22-34 years at cancer diagnosis, are reported; two of them had attenuated FAP. Grossly, one FAP-associated tumour and one sporadic tumour were multicentric and the others were solitary. Histologically, the tumours were encapsulated and exhibited a combination of cribriform, follicular, trabecular, solid, and papillary patterns of growth, with morular areas. Immunohistochemically, the tumour cells showed cytoplasmic expression of thyroglobulin, neuron-specific enolase, epithelial membrane antigen, high- and low-molecular-weight cytokeratins, vimentin, and bcl-2 protein; nuclear expression of oestrogen and progesterone receptors, and retinoblastoma protein; and cytoplasmic and nuclear accumulation of beta-catenin. Germline mutations of the adenomatous polyposis coli (APC) gene were investigated using the protein truncation test in four subjects, including two FAP individuals. Germline APC mutation was identified in only one FAP patient with the multicentric C-MV of PTC, who had a thymidine deletion at codon 512, resulting in a frameshift leading to a premature stop codon. No loss of heterozygosity of loci close to the APC gene was detected in tumour tissues from these four patients. Somatic mutation analysis of exon 3 of the beta-catenin gene (CTNNB1) revealed alterations in seven tumours from all five individuals: one at a serine residue (codon 29), three at amino acids adjacent to serine or threonine residues (codons 22, 39, and 44), and three at other amino acids (codons 49, 54, and 56). Moreover, each of two different tumours examined from two patients with the multicentric C-MV of PTC, had different somatic mutations of the CTNNB1 gene. Taken together, these data suggest that accumulation of mutant beta-catenin contributes to the development of the C-MV of PTC.

    The Journal of pathology 2003;199;1;58-67

  • Predominance of CIN versus MSI in the development of rectal cancer at young age.

    Fernebro E, Halvarsson B, Baldetorp B and Nilbert M

    Department of Oncology, University Hospital, Lund, Sweden. Eva.Fernebro@onk.lu.se

    Background: Development of proximal and distal colorectal cancers involve partly different mechanisms associated with the microsatellite instability (MSI) and the chromosomal instability (CIN) pathways. Colorectal cancers in patients under 50 years of age represent about 5% of the total number of tumors and have been associated with an increased frequency of MSI tumors. However, MSI and CIN may play different roles in the development of colon cancer and rectal cancer, and we have specifically investigated their contribution to the development of rectal cancer at young age.

    Methods: Thirty rectal cancers diagnosed before the age of 50 were characterized for DNA-ploidy, MSI, mutations of KRAS and CTNNB1 and immunohistochemical expression of p53, beta-catenin and of the mismatch repair (MMR) proteins MLH1 and MSH2.

    Results: DNA aneuploidy was detected in 21/30 tumors, KRAS mutations in 6 tumors, no mutations of CTNNB1 were detected but immunohistochemical staining for beta-catenin showed nuclear staining in 6 tumors, and immunohistochemical expression of p53 was detected in 18 tumors. MSI was detected in 3/30 tumors, all of which showed and immunohistochemical loss of staining for the MMR protein MSH2, which strongly indicates a phenotype associated with hereditary nonpolyposis colorectal cancer (HNPCC).

    Conclusions: MSI occurs only in a small fraction of the tumors from young patients with rectal cancer, but when present it strongly indicates an underlying HNPCC-causing mutation, and other mechanisms than HNPCC thus cause rectal cancer in the majority of young patients.

    BMC cancer 2002;2;25

  • APC and CTNNB1 mutations in a large series of sporadic colorectal carcinomas stratified by the microsatellite instability status.

    Løvig T, Meling GI, Diep CB, Thorstensen L, Norheim Andersen S, Lothe RA and Rognum TO

    Institute of Forensic Medicine, The National Hospital, University of Oslo, Norway. tone.lovig@labmed.uio.no

    Background: Adenomatous polyposis coli (APC) and beta-catenin (encoded by CTNNB1) are important components in the WNT signalling pathway, a pathway altered in nearly all colorectal tumours. Conflicting results are reported on whether APC mutations are less common in tumours with a high degree of microsatellite instability (MSI-H) than in microsatellite stable (MSS) ones, and whether mutations in the regulatory domain of CTNNB1 substitute for APC mutations in the MSI-H tumours.

    Methods: A consecutive series of 218 primary colorectal carcinomas, stratified by MSI status, were analysed for mutations in the APC gene (by the protein truncation test) and in the CTNNB1 gene (by single-strand conformation polymorphism).

    Results: APC mutations detected in 66% of the patients were significantly more frequent in the MSS and MSI-L (low) tumours than in the MSI-H tumour group (P < 0.001). The MSI-H tumours tended to have more frameshift mutations than the MSS/MSI-L tumours. The majority of the APC mutations were located in the mutation cluster region (MCR). Patients that had lost all beta-catenin binding sites of the APC gene showed a shorter survival time than patients who retained some or all of these binding sites (P = 0.045). Two mutations were found in the CTNNB1 gene, but neither of them was located in the regulatory domain in exon 3.

    Conclusion: This study confirms that APC mutations are less frequent in MSI-H tumours than in MSS and MSI-L tumours. However, CTNNB1 mutations do not substitute for APC mutations in MSI-H tumours in these Norwegian patients.

    Scandinavian journal of gastroenterology 2002;37;10;1184-93

  • Role of Wnt pathway in medulloblastoma oncogenesis.

    Yokota N, Nishizawa S, Ohta S, Date H, Sugimura H, Namba H and Maekawa M

    Department of Neurosurgery, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.

    To clarify the roles of Wnt pathway in medulloblastoma oncogenesis, immunohistochemical staining of beta-catenin and Wnt-1 and genomic analyses of CTNNB1 (beta-catenin) and AXIN1 (axin 1) were examined in 23 sporadic cases. Accumulation of beta-catenin in tumor cells was immunohistochemically proven in 5 cases; 2 cases showed positive immunoreactivity for Wnt-1 and another 2 showed mutation of either CTNNB1 or AXIN1. AXIN1 mutation was in exon 3, corresponding to GSK-3beta binding site and CTNNB1 mutation was in exon 3, corresponding to its phosphorylation site. Disruption of these proteins could result in upregulation of the Wnt signaling and accumulation of beta-catenin, followed by cell proliferation and medulloblastoma oncogenesis.

    International journal of cancer 2002;101;2;198-201

  • Molecular genetic analysis of malignant melanomas for aberrations of the WNT signaling pathway genes CTNNB1, APC, ICAT and BTRC.

    Reifenberger J, Knobbe CB, Wolter M, Blaschke B, Schulte KW, Pietsch T, Ruzicka T and Reifenberger G

    Department of Dermatology, Heinrich-Heine-University, Düsseldorf, Germany. reifenbergerj@med.uni-duesseldorf.de

    Aberrant activation of the Wnt signaling pathway has been reported in different human tumor types, including malignant melanomas. We investigated 37 malignant melanomas (15 primary tumors and 22 metastases) for alterations of 4 genes encoding members of this pathway, i.e., CTNNB1 (beta-catenin gene, 3p22.1), APC (adenomatous polyposis coli gene, 5q22.2), BTRC (beta-transducin repeat-containing protein gene, 10q24.3) and ICAT (inhibitor of beta-catenin and Tcf-4, 1p36.2). Mutational analysis of CTNNB1 identified somatic mutations in 1 primary melanoma and 1 melanoma metastasis from 2 different patients (5%). Both mutations affected the N-terminal degradation box of beta-catenin, which is important for the regulation of beta-catenin homeostasis. Another primary melanoma carried a somatic APC missense mutation within the known mutation cluster region in exon 15. Fourteen tumors (40%) showed LOH at microsatellite markers on 1p36. None of the tumors had lost both copies of the ICAT gene, but 1 melanoma metastasis carried a somatic point mutation altering the translation start codon of ICAT. Real-time RT-PCR showed markedly reduced ICAT transcript levels (<or=20% relative to normal skin and benign melanocytic nevi) in 28/36 malignant melanomas (78%), including 13/14 tumors with LOH on 1p36. Allelic loss on 10q was detected in 15 tumors (44%). We found neither mutations nor complete loss of expression of the BTRC gene in our melanoma series. Taken together, our results indicate that the Wnt pathway may be altered in malignant melanomas by different mechanisms, including rare somatic mutations in CTNNB1, APC or ICAT, as well as low or absent expression of ICAT transcripts.

    International journal of cancer 2002;100;5;549-56

  • APC/CTNNB1 (beta-catenin) pathway alterations in human prostate cancers.

    Gerstein AV, Almeida TA, Zhao G, Chess E, Shih IeM, Buhler K, Pienta K, Rubin MA, Vessella R and Papadopoulos N

    Department of Pathology, Institute of Cancer Genetics, Columbia University, New York, New York, USA.

    Genetic alterations serve as beacons for the involvement of specific pathways in tumorigenesis. It was previously shown that 5% of prostate tumors harbor CTNNB1 mutations, suggesting that this tumor type may involve a deregulated APC/CTNNB1 pathway. To explore this possibility further, we searched for mutations in genes implicated in this pathway in 22 samples that included cell lines, xenografts, and primary tumors. We identified seven alterations: two in CTNNB1, three in APC, and two in hTRCP1 (also known as BTRC) which controls the degradation of CTNNB1. Alterations in the CTNNB1 regulatory domain, APC, and hTRCP1 were mutually exclusive, consistent with their equivalent effects on CTNNB1 stability. These results suggest that CTNNB1 signaling plays a critical role in the development of a significant fraction of prostate cancers. Moreover, they provide the first evidence that hTRCP1 plays a role in human neoplasia.

    Genes, chromosomes & cancer 2002;34;1;9-16

  • No evidence for involvement of beta-catenin and APC in urothelial carcinomas.

    Stoehr R, Krieg RC, Knuechel R, Hofstaedter F, Pilarsky C, Zaak D, Schmitt R and Hartmann A

    Institute of Pathology, University of Regensburg, 93042 Regensburg, Germany.

    The wnt pathway plays an important role in embryonal patterning and cell fate determination, involving stabilization of nuclear and cytoplasmic beta-catenin (CTNNB1) mediated by APC, axin, and other proteins. Uncomplexed beta-catenin binds to TCF/LEF transcription factors and activates the expression of growth regulatory target genes such as c-myc or cyclin D1. In colorectal and other cancers, constitutive wnt signaling results frequently from mutations in one or more pathway components, e.g. APC and beta-catenin, resulting in nuclear and/or cytoplasmic accumulation of beta-catenin. In the present study, the most frequent alterations in the CTNNB1 and APC genes were investigated in primary urothelial bladder tumors and cell lines. Snap-frozen bladder tumors (n=99) of different stages and grades and 4 cell lines (RT4, RT112, J82, UROtsa) were investigated for APC allelic deletions by loss of heterozygosity (LOH) analysis. The most frequent mutated regions of CTNNB1 (degradation box in the third exon) and APC (mutation cluster region) were directly sequenced. Beta-catenin expression was analyzed by immunofluorescence in the cell lines. LOH at the APC gene locus on chromosome 5q21 was found in 7 of 72 (10%) of the informative cases. No mutations were found in either CTNNB1 or APC. A previously described polymorphism at codon 1493 of the APC gene was detected in 8 tumors and 3 cell lines. All cell lines showed normal membranous beta-catenin staining without evidence for nuclear or cytoplasmic accumulation. Alteration of APC and beta-catenin, which are the most frequent wnt pathway alterations in many tumor types, are rare events in urothelial carcinomas. Other wnt pathway members, such as axin, may play an important role in urothelial carcinogenesis.

    International journal of oncology 2002;20;5;905-11

  • Loss of membranous expression of beta-catenin is associated with tumor progression in cutaneous melanoma and rarely caused by exon 3 mutations.

    Demunter A, Libbrecht L, Degreef H, De Wolf-Peeters C and van den Oord JJ

    Department of Pathology, Laboratory of Morphology and Molecular Pathology, University Hospitals, Katholieke Universiteit Leuven, Belgium. anouk.demunter@uz.kuleuven.ac.be

    beta-Catenin plays a fundamental role in the regulation of the E-cadherin-catenin cell adhesion complex. It also plays a role in the Wnt signaling pathway by activating T-cell factor- and lymphoid enhancer factor-regulated gene transcription. The level of beta-catenin in cells is tightly controlled in a multiprotein complex, and mutations in the glycogen synthase kinase 3beta (GSK-3beta) phosphorylation sites of the beta-catenin gene (CTNNB1) result in nuclear and/or cytoplasmic accumulation of beta-catenin and constitutive transactivation of T-cell factor and lymphoid enhancer factor target genes, a mechanism occurring in many cancers. Melanoma cell lines may harbor beta-catenin mutations; in vivo, however, cellular accumulation of beta-catenin is rarely caused by CTNNB1 mutations. In our study, 43 primary cutaneous melanoma and 30 metastases were screened for CTNNB1 exon 3 mutations by using a denaturing gradient gel electrophoresis technique and sequencing. beta-Catenin mutations were found in 2 primary melanomas and 1 metastatic melanoma and were not correlated with nuclear accumulation of beta-catenin in these cases. Cellular expression of beta-catenin was evaluated by immunohistochemistry and by reverse polymerase chain reaction (RT-PCR) in 80 and 70 cases, respectively. Immunohistochemistry revealed a significant loss of membranous beta-catenin staining between the primary and metastatic melanomas as well as between radial and vertical growth phase. RT-PCR showed a significant inverse correlation between the amount of RNA and the proportion of cells with membranous expression of beta-catenin (P =.0015); no correlation existed between the amount of RNA and the number of cells with nuclear or cytoplasmic expression of beta-catenin. In conclusion, nuclear expression of beta-catenin is seen in cutaneous melanoma but, in contrast to the case of many other cancers, does not correlate with tumor stage or mutation status. A combination of immunohistochemistry and RT-PCR showed that down-regulation of membranous beta-catenin was associated with an increased amount of beta-catenin RNA in primary or metastatic melanoma. Our results suggest that posttranslational events, rather than CTNNB1 mutations, are responsible for the altered distribution of beta-catenin in cutaneous melanoma.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2002;15;4;454-61

  • Mutations in exon 3 of the beta-catenin gene are rare in melanoma cell lines.

    Pollock PM and Hayward N

    Joint Experimental Oncology Program of the Queensland Institute of Medical Research, The University of Queensland, and the Queensland Cancer Fund, P.O. Royal Brisbane Hospital, Herston 4029, Australia.

    Mutations in exon 3 of the CTNNB1 gene encoding beta-catenin have been reported in colorectal cancer cell lines and tumours. Although one study reported mutations or deletions affecting beta-catenin in 20% of melanoma cell lines, subsequent reports detected a much lower frequency of aberrations in uncultured melanomas. To determine whether this difference in mutation frequency reflected an in vitro culturing artefact, exon 3 of CTNNB1 was screened in a panel of 62 melanoma cell lines. In addition, reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect intragenic deletions affecting exon 3. One out of 62 (1.6%) cell lines was found to carry a mutation, indicating that aberration of the Wnt-1/wingless pathway through activation of beta-catenin is a rare event, even in melanoma cell lines.

    Melanoma research 2002;12;2;183-6

  • CTNNB1 mutations and beta-catenin expression in endometrial carcinomas.

    Machin P, Catasus L, Pons C, Muñoz J, Matias-Guiu X and Prat J

    Department of Pathology, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.

    Mutations in the beta-catenin gene (CTNNB 1) with abnormal nuclear accumulation of beta-catenin have recently been identified in endometrial carcinoma (EC). Their relationship with microsatellite instability (MI) is unclear. It has been suggested that matrix metalloproteinase-7 (MMP-7) and cyclin D1 (cD) genes are targets for beta-catenin activation. DNA from 73 patients with EC was obtained from tumor and normal tissue (59 endometrioid and 14 nonendometrioid). CTNNB 1 mutations in exon 3 were assessed by single-strand conformation polymorphism and DNA sequencing. The results were correlated with immunostaining for beta-catenin, MMP-7, and cD. Three (CA)n repeats and mononucleotide tracts BAT 25 and BAT 26 had been previously used for MI analysis. CTNNB1 mutations were identified in 15 ECs (20.5%), all of them endometrioid carcinomas (15 of 59; 25.4%). They occurred in 6 of 19 MI-positive ECs (31.5%) and in 9 of 54 MI-negative ECs (16.6%). Eleven of the 15 CTNNB 1-mutated ECs showed beta-catenin nuclear immunostaining (P <.05). MMP-7 expression (>50% cells) was observed in 23 ECs, with 7 of these showing CTNNB 1 mutations. Significant expression of cD (>50% cells) was detected in 8 ECs, with 5 of these exhibiting CTNNB 1 mutations (P <.05). The results confirm that beta-catenin plays a role in endometrial carcinogenesis, particularly in endometrioid carcinomas. The results also suggest that MMP-7 and particularly cD may be targets of beta-catenin activation in ECs.

    Human pathology 2002;33;2;206-12

  • Diverse mechanisms of beta-catenin deregulation in ovarian endometrioid adenocarcinomas.

    Wu R, Zhai Y, Fearon ER and Cho KR

    Department of Pathology, The University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA.

    Clinical and molecular findings suggest that the four major histological subtypes of ovarian carcinoma (serous, clear cell, mucinous, and endometrioid) likely represent distinct disease entities. Prior studies have shown that ovarian endometrioid adenocarcinomas (OEAs) often carry mutations in the CTNNB1 gene, which encodes beta-catenin, a critical component of the Wnt signaling pathway. However, the nature of other defects in the Wnt signaling pathway in ovarian carcinomas remains largely unknown. Thus, in 45 primary OEAs and two OEA-derived cell lines, we sought to comprehensively address the prevalence of and mechanisms underlying beta-catenin and Wnt pathway deregulation. CTNNB1 missense mutations were detected in 14 primary tumors. All mutations affected the NH(2)-terminal regulatory domain of beta-catenin, presumably rendering the mutant proteins resistant to degradation. Immunohistochemical studies revealed nuclear accumulation of beta-catenin in all but two tumors with CTNNB1 mutations. Two primary tumors lacking CTNNBI mutations showed strong nuclear immunoreactivity for beta-catenin. In one of the two tumors, biallelic inactivation of the APC gene was found. In the remaining 29 primary OEAs, unequivocal nuclear beta-catenin immunoreactivity was not observed, though a nonsense mutation in AXIN1 was observed in one tumor and a truncating frameshift mutation in AXIN2 was seen in another case. Both OEA-derived cell lines studied (TOV-112D and MDAH-2774) had elevated constitutive T-cell factor/lymphoid enhancer factor transcriptional activity. TOV-112D cells were shown to harbor mutant beta-catenin, whereas a missense AXIN1 sequence alteration was identified in MDAH-2774 cells. Collectively, our findings demonstrate frequent defects of the Wnt signaling pathway in a particular subtype of ovarian carcinomas, i.e., OEAs. Although mutations in the CTNNB1 gene are the most common mechanism of beta-catenin deregulation in OEAs, beta-catenin deregulation may also result from mutations in the APC, AXIN1, and AXIN2 genes.

    Cancer research 2001;61;22;8247-55

  • Somatic mutations of WNT/wingless signaling pathway components in primitive neuroectodermal tumors.

    Koch A, Waha A, Tonn JC, Sörensen N, Berthold F, Wolter M, Reifenberger J, Hartmann W, Friedl W, Reifenberger G, Wiestler OD and Pietsch T

    Department of Neuropathology, University of Bonn Medical Center; Bonn, Germany.

    Primitive neuroectodermal tumors (PNETs) represent the most frequent malignant brain tumors in childhood. The majority of these neoplasms occur in the cerebellum and are classified as medulloblastomas (MB). Most PNETs develop sporadically; however, their incidence is highly elevated in patients carrying germline APC gene mutations. The APC gene encodes a central component of the WNT/wingless developmental signaling pathway. It regulates the levels of cytoplasmic beta-catenin protein that plays a central role in neural development and cell proliferation. We analyzed 87 sporadic PNETs and 10 PNET cell lines for mutations of the APC gene and beta-catenin (CTNNB1) gene using single strand conformational polymorphism (SSCP) and sequencing analysis. We examined the mutation cluster region of APC (codons 1255--1641) for germline variants and somatic mutations. The medulloblastoma cell line MHH-MED-2 carried a Glu1317Gln missense germline variant and a sporadic MB sample showed a somatic Pro1319Leu substitution. Mutational analysis of exon 3 of CTNNB1 uncovered 4 PNETs (4.8%) with somatic missense mutations. These mutations caused amino acid substitutions in 3 of 80 medulloblastomas (Ser33Phe, Ser33Cys and Ser37Cys) and 1 of 4 supratentorial PNETs (Gly34Val). All mutations affected GSK-3 beta phosphorylation sites of the degradation targeting box of beta-catenin and resulted in nuclear beta-catenin protein accumulation. Deletions of CTNNB1 were not detected by PCR amplification with primers spanning exons 1--5. Our data indicate that inappropriate activation of the WNT/wingless signaling pathway by mutations of its components may contribute to the pathogenesis of a subset of PNETs.

    International journal of cancer 2001;93;3;445-9

  • Genetic alteration of the beta-catenin gene (CTNNB1) in human lung cancer and malignant mesothelioma and identification of a new 3p21.3 homozygous deletion.

    Shigemitsu K, Sekido Y, Usami N, Mori S, Sato M, Horio Y, Hasegawa Y, Bader SA, Gazdar AF, Minna JD, Hida T, Yoshioka H, Imaizumi M, Ueda Y, Takahashi M and Shimokata K

    Department of Thoracic Surgery, Nagoya University School of Medicine, Nagoya 466-8550, Japan.

    The beta-catenin gene (CTNNB1) has been shown to be genetically mutated in various human malignancies. To determine whether the beta-catenin gene is responsible for oncogenesis in thoracic malignancies, we searched for the mutation in 166 lung cancers (90 primary tumors and 76 cell lines), one blastoma and 10 malignant mesotheliomas (two primary tumors and eight cell lines). Among the lung cancers, including 43 small cell lung cancers (SCLCs) and 123 non-small cell lung cancers (NSCLCs), we identified four alterations in exon 3, which is the target region of mutation for stabilizing beta-catenin. One primary adenocarcinoma had a somatic mutation from C to G, leading to an amino acid substitution from Ser to Cys at codon 37. Among the cell lines, SCLC NCI-H1092 had a mutation from A to G, leading to an Asp to Gly substitution at codon 6, NSCLC HCC15 had a mutation from C to T, leading to a Ser to Phe substitution at codon 45, and NSCLC NCI-H358 had a mutation from A to G, leading to a Thr to Ala substitution at codon 75. One blastoma also had a somatic mutation from C to G, leading to a Ser to Cys substitution at codon 37. Among the 10 malignant mesotheliomas, we identified a homozygous deletion in the NCI-H28 cell line. Cloning of the rearranged fragment from NCI-H28 indicated that all the exons except exon 1 of the beta-catenin gene are deleted and that the deletion junction is 13 kb downstream from exon 1. Furthermore, Northern blot analysis of 26 lung cancer and eight mesothelioma cell line RNAs detected ubiquitous expression of the beta-catenin messages except NCI-H28, although Western blot analysis showed that relatively less amounts of protein products were expressed in some of lung cancer cell lines. Our findings suggest that the beta-catenin gene is infrequently mutated in lung cancer and that the NCI-H28 homozygous deletion of the beta-catenin gene might indicate the possibility of a new tumor suppressor gene residing in this region at 3p21.3, where various types of human cancers show frequent allelic loss.

    Funded by: NCI NIH HHS: CA71618, P50 CA70907

    Oncogene 2001;20;31;4249-57

  • Beta-catenin activation through mutation is rare in rectal cancer.

    Nilbert M and Rambech E

    Department of Oncology, University Hospital, 221 85 Lund, Sweden. mef.nilbert@onk.lu.se

    Increased transcriptional activation through beta-catenin stabilization plays a central role in colorectal tumorigenesis. Alterations of phosphorylation sites within the CTNNB1 gene, which codes for beta-catenin has been reported to occur in about one-half of colorectal tumors without APC-gene mutations. We assessed the importance of mutations in the regulatory domain, located within exon 3 of CTNNB1, in 103 rectal carcinomas and correlated these data with presence of microsatellite instability, somatic frame-shift alterations of the TCF-4 gene, and APC-gene mutations in the tumors. No mutation was detected in exon 3 of the CTNNB1 gene and our results thus demonstrate that beta-catenin activation through mutation rarely contributes to the development of sporadic and microsatellite instability stable rectal cancer.

    Cancer genetics and cytogenetics 2001;128;1;43-5

  • beta-Catenin gene mutation in human hair follicle-related tumors.

    Kajino Y, Yamaguchi A, Hashimoto N, Matsuura A, Sato N and Kikuchi K

    Department of Laboratory Medicine, Shiga University of Medical Science, Ohtsu, Japan.

    beta-Catenin, a multifunctional protein related to the adherens junction and to signal transduction, is a key molecule of cell proliferation, and it is central to epithelial architecture, regulating the polarity of cells and tissues. beta-Catenin stabilization may play a key role in epidermal signaling leading to hair development, and its aberrant activation may be implicated in formation of hair tumors. Several investigators have shown that pilomatricomas are frequently associated with beta-catenin mutation. In this study, we confirmed beta-catenin gene (CTNNB1) mutation in human pilomatricomas (100% frequency) from which adequate DNA could be obtained for gene analysis. A novel mutation, D32N, was found in one case of pilomatricoma. A preliminary immunohistological study revealed prominent beta-catenin staining in basophilic cells of pilomatricomas, especially in nuclei. Benign tumors which were considered to be derived from hair matrix or hair follicles, and other benign skin tumors, were also investigated. beta-Catenin mutations were not detected in any of the these tumors. These results seem to indicate that hair matrix cells are key players in hair development. Investigation into gene abnormalities of hair-follicle tumors may elucidate the cause of their neoplastic transformation, and may provide a suggestion for the mechanism of hair development.

    Pathology international 2001;51;7;543-8

  • Cytoplasmic and nuclear accumulation of beta-catenin is rarely caused by CTNNB1 exon 3 mutations in cutaneous malignant melanoma.

    Omholt K, Platz A, Ringborg U and Hansson J

    Cancer Centre Karolinska, Department of Oncology-Pathology, Radiumhemmet, Karolinska Hospital, Stockholm, Sweden.

    Beta-catenin plays an important role in the Wnt signaling pathway by activating T-cell factor (Tcf)/lymphoid enhancer factor (Lef)-regulated gene transcription. The level of beta-catenin is regulated through GSK-3beta phosphorylation of specific serine and threonine residues, all of which are encoded for in exon 3 of the beta-catenin gene (CTNNB1). Mutations altering the GSK-3beta phosphorylation sites lead to cellular accumulation of beta-catenin and constitutive transcription of Tcf/Lef target genes. Such mutations have previously been found in melanoma cell lines. In our study, primary melanomas and their corresponding metastases were screened for CTNNB1 exon 3 mutations using single-strand conformation polymorphism and nucleotide sequence analysis. One of 31 primary tumors and 1 of 37 metastases, both originating from the same patient, had a TCT to TTT mutation at codon 45, changing serine to phenylalanine. Immunohistochemical analysis revealed membranous localization of beta-catenin in a majority of the samples. The mutated primary tumor and metastasis, however, displayed widespread cytoplasmic and nuclear expression of beta-catenin. An additional 30% of the primary tumors showed focal cytoplasmic and nuclear staining. Thus, beta-catenin exon 3 mutations are rare in primary as well as metastatic melanomas and do not explain the abnormal cytoplasmic and nuclear localization of beta-catenin found in a relatively large fraction of primary melanomas.

    International journal of cancer 2001;92;6;839-42

  • CTNNB1 mutations and beta-catenin protein accumulation in human hepatocellular carcinomas associated with high exposure to aflatoxin B1.

    Devereux TR, Stern MC, Flake GP, Yu MC, Zhang ZQ, London SJ and Taylor JA

    Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina 27709, USA.

    beta-Catenin plays a key role in the Wnt signaling pathway, and mutations of CTNNB1, the gene that encodes beta-catenin, have been identified in about one-fourth of human hepatocellular carcinomas from regions of low aflatoxin B1 exposure. In this study 62 hepatocellular carcinomas (HCCs) from people highly exposed to aflatoxin B1 in Guangxi, People's Republic of China, were laser-capture microdissected and examined for CTNNB1 mutations. In addition, 41 of the HCCs were evaluated for the presence of the beta-catenin protein by immunohistochemical methods. Twenty of the HCCs showed positive results for beta-catenin, with strong membrane staining, while adjacent non-neoplastic liver tissue lacked or showed only weak membrane staining. One HCC, in which a CTNNB1 mutation was not detected, showed nuclear staining for the beta-catenin protein. Mutations of CTNNB1 were identified in five HCCs. These consisted of four point mutations in the glycogen serine kinase-3beta phosphorylation region of codons 32-45 and one deletion of codons 32-38. These mutations were similar to those previously reported for human HCC, although at a lower frequency. A signature mutation profile associated with aflatoxin B1 exposure could not be identified. The immunohistochemical findings indicate a role for accumulation of beta-catenin and possibly increased Wnt signaling in aflatoxin B1-associated HCC. The low frequency of CTNNB1 mutations, however, suggests that mutation of another Wnt signaling component, such as the Wnt scaffolding protein axin or the adenomatous polyposis coli protein, both of which modulate beta-catenin stability, also may be involved in aflatoxin-associated HCC. Published 2001 Wiley-Liss, Inc.

    Funded by: NCI NIH HHS: R35 CA 53890

    Molecular carcinogenesis 2001;31;2;68-73

  • Beta-catenin dysregulation in thyroid neoplasms: down-regulation, aberrant nuclear expression, and CTNNB1 exon 3 mutations are markers for aggressive tumor phenotypes and poor prognosis.

    Garcia-Rostan G, Camp RL, Herrero A, Carcangiu ML, Rimm DL and Tallini G

    Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA. ggarcia@cnio.es

    beta-catenin has a role in cell adhesion and Wnt signaling. It is mutated or otherwise dysregulated in a variety of human cancers. In this study we assess beta-catenin alteration in 145 thyroid tumors samples from 127 patients. beta-catenin was localized using immunofluorescence and mutational analysis was performed by single-strand conformational polymorphism. Membrane beta-catenin expression was decreased in eight of 12 (66%) adenomas and in all 115 carcinomas (P: < 0.0001). Among carcinomas, reduced membrane beta-catenin was associated with progressive loss of tumor differentiation (P: < 0.0001). CTNNB1 exon 3 mutations and nuclear beta-catenin localization were restricted to poorly differentiated [7 of 28 (25%) and 6 of 28 cases (21.4%), respectively] or undifferentiated carcinomas [19 of 29 (65.5%) and 14 of 29 (48.3%) cases, respectively]. Poorly differentiated tumors always featured mutations involving Ser and Thr residues and were characterized by Thr to Ile amino acid substitutions (P: = 0.0283). The association between CTNNB1 exon 3 mutations and aberrant nuclear immunoreactivity (P: = 0.0020) is consistent with Wnt activation because of stabilizing beta-catenin mutations. Low membrane beta-catenin expression as well as its nuclear localization or CTNNB1 exon 3 mutations are significantly associated with poor prognosis, independent of conventional prognostic indicators for thyroid cancer but not of tumor differentiation. Analysis of beta-catenin dysregulation may be useful to objectively subtype thyroid neoplasms and more accurately predict outcomes.

    The American journal of pathology 2001;158;3;987-96

  • Constitutive activation of the Wnt signaling pathway by CTNNB1 (beta-catenin) mutations in a subset of human lung adenocarcinoma.

    Sunaga N, Kohno T, Kolligs FT, Fearon ER, Saito R and Yokota J

    Biology Division, National Cancer Center Research Institute, Tokyo, Japan.

    Constitutive activation of the Wnt signaling pathway as a result of genetic alterations of APC, AXIN1, and CTNNB1 has been found in various human cancers, including those of the colon, liver, endometrium, ovary, prostate, and stomach. To investigate the pathogenetic significance of constitutive activation of the Wnt signaling pathway in human lung carcinogenesis, CTNNB1 alterations in exon 3, a region known to represent a mutation hot spot, were screened in 46 lung cancer cell lines and 47 primary lung cancers. Missense mutations causing substitutions of Ser/Thr residues critical for regulation by GSK-3beta were detected in one (2%) of the cell lines, A427, and two (4%) of the surgical specimens. The three lung cancers with CTNNB1 mutations were adenocarcinomas. To explore the prevalence of constitutive activation of the Wnt signaling pathway in human lung cancer, we assessed 15 lung cancer cell lines representing major histological subtypes of lung cancers for constitutive Tcf transcriptional activity (CTTA). CTTA was observed only in the A427 adenocarcinoma cell line, but not in the remaining 14 cell lines. The data indicate that constitutive activation of the Wnt signaling pathway caused by CTNNB1 mutation is involved in the development and/or progression of a subset of lung carcinoma, preferentially in adenocarcinoma.

    Genes, chromosomes & cancer 2001;30;3;316-21

  • Mutational analysis of the CTNNB1 and APC genes in uterine endometrioid carcinoma.

    Schlosshauer PW, Pirog EC, Levine RL and Ellenson LH

    Department of Pathology, Joan and Sanford I. Weill Medical College of Cornell University, New York, USA.

    Despite recent studies, the molecular genetic events responsible for the development of uterine endometrioid carcinoma (UEC) remain incompletely characterized. Mutations in the beta-catenin (CTNNB1) gene have been recently reported in a small percentage of UECs and in the endometrioid variant of ovarian carcinoma suggesting that the Wnt signal transduction pathway is involved in the development of female genital tract tumors with endometrioid morphology. The Wnt pathway is a critical pathway in the development of colorectal cancer (CRC) with mutations occurring in the beta-catenin (CTNNB1) or adenomatous polyposis coli (APC) genes in 10 to 15% and 85% of cases, respectively. Because UEC and CRC share other molecular genetic alterations and histologic features and previous studies of UEC have not reported an analysis of the APC gene, we chose to further elucidate the role of the Wnt pathway in UEC. To this end, we analyzed 32 cases of UEC for mutations of the CTNNB1 and APC genes. Mutations of CTNNB1 were present in six of 32 (18%) cases: four grade 1 carcinomas, one grade 2, and one grade 3 carcinoma. Five missense mutations were identified, three involving Ser/Thr phosphorylation sites and two adjacent to a Ser phosphorylation site. One case contained a deletion encompassing codons 34 to 37, which includes a Ser phosphorylation site. No mutations resulting in truncation of the APC protein were found. Our results support a role for the Wnt signaling pathway via mutation of CTNNB1, but not APC, in the development of a subset of UECs.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2000;13;10;1066-71

  • [Mutation analysis of the beta-catenin gene in epithelial carcinomas of the ovaries].

    Tanyi J, Páy A, Rigó J, Nagy B and Papp Z

    Altalános Orvostudományi Kar, Semmelweis Egyetem, Budapest.

    beta-catenin is a continuously expressed cytoplasmic protein that has an important role is both E-cadherin-mediated cell-cell adhesion and in activation of Wnt/Wingless transcriptional pathway. The accumulation of stabilized beta-catenin caused by the mutation of the exon 3 of beta-catenin gene can stimulate the T-cell factor/Lymphoid enhancing factor-mediated transcriptional activation. The activation of transcriptional pathway may through oncogenes is an important step of the oncogenesis in solid tumors. In this study we analyzed mutations in exon 3 of the beta-catenin gene in 18 sporadic epithelial ovarian tumors. Three mutations were found from these 18 ovarian tumor samples which contained 8 serous, 3 mucinous, 5 endometrioid, one malignant Brenner-type tumor and one transitional cell carcinoma. Two mutations occurred in endometrioid-type (in 47 and 55 codons) and one in serous-type (in 47 codon) ovarian carcinomas, and both mutations were missense and somatic. The patients with mutated beta-catenin gene appeared from the younger patients under the age of 50. Our results suggest that the stabilization of beta-catenin protein by the mutation of CTNNB1 gene can contribute to the multistep process of the oncogenesis of epithelial ovarian tumors. Furthermore these mutations mostly occurs in the endometrioid-type of EOT, but can appear in other types such as serous-type ovarian tumor.

    Orvosi hetilap 2000;141;21;1115-9

  • Mutational analysis of the CTNNB1 (beta-catenin) gene in human endometrial cancer: frequent mutations at codon 34 that cause nuclear accumulation.

    Ikeda T, Yoshinaga K, Semba S, Kondo E, Ohmori H and Horii A

    Department of Molecular Pathology, Tohoku University School of Medicine, Sendai 980-8575, Japan.

    Recently, CTNNB1 (beta-catenin) has been found to function as an oncoprotein that works in the Wnt signaling pathway, and mutation of this gene has been reported in various human cancers. In this study, we analyzed 44 endometrial cancers and found somatic missense mutations in five (11%) tumors. Interestingly, four (80%) of the five tumors with mutations would cause amino acid alterations at residues next to Ser 33, one of the targets for phosphorylation of glycogen synthase kinase (GSK)-3beta. The tumors with mutations showed accumulation of the CTNNB1 protein in cytoplasm and nucleus. This is the first report of frequent somatic mutation of the CTNNB1 gene at codons adjacent to those encoding to Ser/Thr residues in endometrial cancer.

    Oncology reports 2000;7;2;323-6

  • [beta-Catenine as a genomic target of high-grade microsatellite instability in colorectal cancer].

    Kölble K, Barthel B, Ullrich O, Pidde H, Döhring C, Rüschoff J, Schlag PM and Dietel M

    Institut für Pathologie, Universitätsklinikum Charité, Humboldt-Universität, Berlin.

    Aims: Various inherited and acquired alterations affecting the genes and gene products of the WNT pathway appear to be involved in the different molecular routes leading to colorectal cancer (CRC). This study was initiated to investigate the prevalence of somatic mutations in the beta-catenin gene (CTNNB1) and the associated pathology in CRC with defective DNA mismatch repair.

    Methods: Paraffin and/or frozen sections of 33 primary CRC (including any liver and lymph node metastases present) with high-grade microsatellite instability (MSI-H; i.e. with > or = 5 unstable microsatellite markers of 10 tested) were polytopically fractionated by microdissection. Genomic and c-DNA samples were sequenced across exons 2-4 of CTNNB1 and the expression patterns of beta-catenin (beta-C) analyzed by immunohistology and Western blotting.

    Results: Seven somatic mutations affecting phosphorylation sites of exon 3 (2 deletions also encompassing parts of either intron 2 or exon 4 [delta X2/3 bzw. delta X3/4] and 5 missense mutations [2 x T41A, 2 x S45F, S45P]) were identified. Two mutations (delta X3/4 and S45F) were concordantly present in CRC primaries and their respective metastases whereas the S45P mutation was restricted to a hepatic metastasis. In the delta X2/3 CRC primary only a shortened 66 kD CTNNB1 gene product was present while its associated liver metastasis showed a total loss of beta-C expression.

    Conclusions: Both exon 3 and the entire locus coding for beta-C are somatically altered in approximately 20% of CRC with MSI-H at different stages of tumor progression. Thus CTNNB1 appears to be a genomic target for complex oncogenic mutations and deletional processes in a substantial fraction of this molecular subset of CRC.

    Verhandlungen der Deutschen Gesellschaft fur Pathologie 2000;84;182-6

  • A novel case of a sporadic desmoid tumour with mutation of the beta catenin gene.

    Shitoh K, Konishi F, Iijima T, Ohdaira T, Sakai K, Kanazawa K and Miyaki M

    Hereditary Tumour Research Project, Tokyo Metropolitan Komagome Hospital, Japan.

    A 42 year old man without familial adenomatous polyposis had recurrent desmoid tumours in the left subclavicular site. Histological examination showed a typical desmoid tumour. Molecular analysis was performed in genomic DNA from this tumour, using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and direct sequencing methods. No mutation could be detected in the entire coding sequence of the APC gene, nor in H-ras, K-ras, N-ras, or p53 genes. On seeking a mutation of the beta catenin gene (CTNNB1), an activating mutation from ACC (Thr) to GCC (Ala) at codon 41 was found. Immunohistochemical staining showed that accumulated beta catenin protein was predominantly localised in the nuclei of desmoid cells. This is the first example of a sporadic desmoid tumour in which a mutation of the beta catenin gene was revealed.

    Journal of clinical pathology 1999;52;9;695-6

  • beta-catenin mutation and expression analysis in ovarian cancer: exon 3 mutations and nuclear translocation in 16% of endometrioid tumours.

    Wright K, Wilson P, Morland S, Campbell I, Walsh M, Hurst T, Ward B, Cummings M and Chenevix-Trench G

    Joint Experimental Oncology Program, Queensland Institute of Medical Research and University of Queensland, Brisbane, Australia.

    The molecular mechanisms involved in the generation of epithelial ovarian cancers are poorly understood, but evidence suggests that the different histological subtypes may arise from independent tumorigenic events. beta-Catenin is emerging as an important oncogene in the transformation of a number of epithelial cancers, and mutations have been reported in a small study of endometrioid ovarian adenocarcinomas. Mutations in the NH(2)-regulatory domain of beta-catenin stabilise the cytoplasmic levels of this protein, which promotes up-regulation of the beta-catenin-T-cell factor-lymphoid enhancer factor transcriptional complex. We report here beta-catenin (CTNNB1) exon 3 mutation analysis in 149 epithelial ovarian carcinomas. This revealed 10/63 (16%) endometrioid ovarian tumours with activating mutations of the beta-catenin gene. All mutations were missense changes within the GSK3beta consensus site, affecting serine residues at codons 33 and 37 and glycine at codon 34. Immuno-histochemical analysis identified cytoplasmic stabilisation and nuclear translocation in those endometrioid tumours with mutations. This phenotypic change was also identified in 3 other endometrioid tumours that did not have somatic mutations within exon 3 of CTNNB1. Stabilisation of the free, monomeric pool of beta-catenin and the probable resulting constitutive activation of its Tcf-associated transcriptional complex appears to be a specific oncogenic event in endometrioid ovarian adenocarcinoma.

    International journal of cancer 1999;82;5;625-9

  • Beta-catenin accumulation and mutation of the CTNNB1 gene in hepatoblastoma.

    Bläker H, Hofmann WJ, Rieker RJ, Penzel R, Graf M and Otto HF

    Department of Pathology, University of Heidelberg, Heidelberg, Germany. hendrik_blaeker@ukl.uni-heidelberg.de

    Hepatoblastoma is a rare malignant tumor of the liver that occurs in children at an average age of 2 to 3 years. Epidemiologic studies have shown an increased frequency of this tumor type in families affected by adenomatous polyposis coli. In addition to the epidemiologic data, molecular genetic studies suggest that inactivation of the APC tumor suppressor may be involved in hepatoblastoma tumorigenesis. A major function of APC is the downregulation of beta-catenin, a transcription-activating protein with oncogenic potential. In an ongoing immunohistochemical study of beta-catenin expression in sporadic cases of tumor types that are associated with adenomatous polyposis coli, we observed increased beta-catenin levels in the cytoplasm and in the nuclei of three investigated hepatoblastomas. Sequencing of exon 3 of the beta-catenin gene (CTNNB1) revealed an activating mutation in one of the tumor samples. Our data indicate for the first time that beta-catenin accumulation may play a role in the development of hepatoblastoma and that activating mutations of the beta-catenin gene may substitute biallelic APC inactivation in this tumor type. Genes Chromosomes Cancer 25:399-402, 1999.

    Genes, chromosomes & cancer 1999;25;4;399-402

  • Germline mutations are frequent in the APC gene but absent in the beta-catenin gene in familial adenomatous polyposis patients.

    Cao X, Eu KW, Seow-Choen F and Cheah PY

    Department of Colorectal Surgery, Singapore General Hospital, Outram Road, Republic of Singapore.

    Inactivation of the adenomatous polyposis coli (APC) gene has been shown to initiate the majority of colorectal cancer (CRC), including a familial form called familial adenomatous polyposis (FAP). One consequence of the APC mutation is the activation of the beta-catenin (CTNNB1)/T-cell transcription factor (Tcf) pathway. A recent study has shown that about half of the sporadic CRC lacking APC mutation has CTNNB1 mutation, suggesting that CTNNB1 mutation can substitute for APC mutation in the initiation of colorectal tumorigenesis. However, the frequency of CTNNB1 germline mutation in FAP has not been reported. In the present study, we investigated the frequencies of APC and CTNNB1 germline mutations in 26 unrelated FAP families. We used the Protein Truncation Test (PTT) to screen the entire coding region of APC and found germline mutations in twenty families. We then screened for CTNNB1 germline mutations in the rest of the families lacking detectable APC mutations. No missense mutations at GSK-3beta phosphorylation sites or interstitial deletion of exon 3 of CTNNB1 was found. Our results indicate that APC germline mutations are frequent but CTNNB1 germline mutations are rare in FAP patients, suggesting that CTNNB1 mutation cannot substitute for APC mutation in the initiation of FAP. Genes Chromosomes Cancer 25:396-398, 1999.

    Genes, chromosomes & cancer 1999;25;4;396-8

  • Beta-catenin mutations are specific for colorectal carcinomas with microsatellite instability but occur in endometrial carcinomas irrespective of mutator pathway.

    Mirabelli-Primdahl L, Gryfe R, Kim H, Millar A, Luceri C, Dale D, Holowaty E, Bapat B, Gallinger S and Redston M

    Centre for Cancer Genetics, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.

    Some colorectal tumors with wild-type adenomatous polyposis coli gene have activating mutations in beta-catenin (encoded by CTNNB1) that result in decreased phosphorylation by GSK-3beta and increased signaling through the Tcf/Lef transcription factors. To investigate the relationship between CTNNB1 mutations and underlying pathways of genomic instability, we examined 80 colorectal cancers stratified by the presence or absence of microsatellite instability (MSI). CTNNB1 mutations were identified in 13 (25%) of 53 cancers with high frequency MSI (MSI-H), including 12 point mutations at exon 3 phosphorylation sites (codons 41 and 45) and one deletion of the entire exon 3 degradation box. No CTNNB1 mutations were identified in 27 microsatellite stable or low frequency MSI (MSI-L) colorectal cancers (P < 0.01). In contrast, CTNNB1 mutations were identified in 3 of 9 (33%) MSI-H and 10 of 20 (50%) MSS/MSI-L endometrial carcinomas, suggesting a more generalized involvement in these tumors. Only six (46%) of the endometrial carcinoma CTNNB1 mutations occurred at residues directly phosphorylated by GSK-3beta, and only one of these was at either codon 41 or 45. All point mutations in MSI-H cancers were transitions, whereas 64% of those in MSS/MSI-L cancers were transversions (P < 0.01). The differences in the mutation profiles suggest that there may be molecular fingerprints of CTNNB1 mutations, determined by biological factors related to both tumor type and underlying pathways of genomic instability.

    Cancer research 1999;59;14;3346-51

  • A common human skin tumour is caused by activating mutations in beta-catenin.

    Chan EF, Gat U, McNiff JM and Fuchs E

    Howard Hughes Medical Institute, Department of Molecular Genetics and Cell Biology, The University of Chicago, Illinois 60637, USA.

    WNT signalling orchestrates a number of developmental programs. In response to this stimulus, cytoplasmic beta-catenin (encoded by CTNNB1) is stabilized, enabling downstream transcriptional activation by members of the LEF/TCF family. One of the target genes for beta-catenin/TCF encodes c-MYC, explaining why constitutive activation of the WNT pathway can lead to cancer, particularly in the colon. Most colon cancers arise from mutations in the gene encoding adenomatous polyposis coli (APC), a protein required for ubiquitin-mediated degradation of beta-catenin, but a small percentage of colon and some other cancers harbour beta-catenin-stabilizing mutations. Recently, we discovered that transgenic mice expressing an activated beta-catenin are predisposed to developing skin tumours resembling pilomatricomas. Given that the skin of these adult mice also exhibits signs of de novo hair-follicle morphogenesis, we wondered whether human pilomatricomas might originate from hair matrix cells and whether they might possess beta-catenin-stabilizing mutations. Here, we explore the cell origin and aetiology of this common human skin tumour. We found nuclear LEF-1 in the dividing tumour cells, providing biochemical evidence that pilomatricomas are derived from hair matrix cells. At least 75% of these tumours possess mutations affecting the amino-terminal segment, normally involved in phosphorylation-dependent, ubiquitin-mediated degradation of the protein. This percentage of CTNNB1 mutations is greater than in all other human tumours examined thus far, and directly implicates beta-catenin/LEF misregulation as the major cause of hair matrix cell tumorigenesis in humans.

    Funded by: NIAMS NIH HHS: NIH-RO1-AR31737; NIDCR NIH HHS: NCI-P50DE/CA-11921

    Nature genetics 1999;21;4;410-3

  • Beta-catenin mutations in human prostate cancer.

    Voeller HJ, Truica CI and Gelmann EP

    Division of Hematology/Oncology, Lombardi Cancer Center, Georgetown University School of Medicine, Washington, DC 20007-2197, USA.

    Beta-catenin plays essential roles in both intercellular adhesion and signal transduction. As a signaling molecule, beta-catenin supplies an activating domain to the T-cell factor/lymphoid enhancer-binding factor family of DNA-binding proteins and activates gene transcription. Posttranslational stabilization of beta-catenin, leading to elevated protein levels and constitutive gene activation, has been proposed as an important step in oncogenesis. Stabilization of beta-catenin can occur through mutation to highly conserved amino acids encoded in exon 3 of the beta-catenin gene (CTNNB1). To determine whether this pathway of malignant transformation is important in prostate cancer, we analyzed 104 prostate cancer tissue specimens, 4 prostate cancer cell lines, and 3 prostate tumor xenografts for activating mutations in exon 3 of CTNNB1. Mutations were detected in 5 of the 104 prostate cancer tissue samples. Four of the five mutations involved serine or threonine residues implicated in the degradation of beta-catenin. A fifth tumor had a mutation at codon 32, changing a highly conserved aspartic acid to a tyrosine. Mutational analysis of multiple regions from several tumor samples showed that the beta-catenin mutations were present focally and therefore may occur during tumor progression.

    Funded by: NCI NIH HHS: P30-CA-51008

    Cancer research 1998;58;12;2520-3

  • Mutations in the beta-catenin gene (CTNNB1) in endometrioid ovarian carcinomas.

    Palacios J and Gamallo C

    Departamento de Anatomía Patológica, Hospital Universitario La Paz (Universidad Autónoma de Madrid), Spain.

    Mutations of the beta-catenin gene (CTNNB1) have recently been implicated in the initiation of some colon carcinomas and melanomas. In these tumors, beta-catenin abnormally accumulates in the cell nuclei. In an ongoing immunohistochemical study of the cadherin-catenin complex protein expression in ovarian carcinomas, we observed beta-catenin in tumor cell nuclei in some cases; this prompted us to study whether or not this abnormal immunostaining pattern was due to mutation in the beta-catenin gene itself. This study examines beta-catenin immunohistochemical expression in 40 stage I and II ovarian borderline tumors and carcinomas of the most common histological types. Membrane expression was heterogeneous in all 40 cases. However, the cytoplasm and nucleus of five (one borderline tumor and four carcinomas) of the six endometrioid lesions contained beta-catenin expression. PCR and sequencing analyses of a 200-bp fragment of exon 3 of the CTNNB1 gene, encompassing the sequence for glycogen synthetase kinase-3beta phosphorylation, were performed in 11 tumors. Heterozygous substitution mutations at codon 37 in two cases (S37F and S37C) and at codon 41 in one case (T41A) were found in three endometrioid lesions (one borderline tumor and two carcinomas) with abnormal beta-catenin expression. Three endometrioid carcinomas and five tumors of other histological types analyzed showed normal DNA sequences. These results implicate beta-catenin gene mutations in ovarian malignant transformation with a characteristic phenotype: endometrioid ovarian carcinoma.

    Cancer research 1998;58;7;1344-7

  • Mutational analysis of the APC/beta-catenin/Tcf pathway in colorectal cancer.

    Sparks AB, Morin PJ, Vogelstein B and Kinzler KW

    Johns Hopkins Oncology Center, Baltimore, Maryland 21231, USA.

    Mutation of the adenomatous polyposis coli (APC) tumor suppressor gene initiates the majority of colorectal (CR) cancers. One consequence of this inactivation is constitutive activation of beta-catenin/Tcf-mediated transcription. To further explore the role of the APC/beta-catenin/Tcf pathway in CR tumorigenesis, we searched for mutations in genes implicated in this pathway in CR tumors lacking APC mutations. No mutations of the gamma-catenin (CTNNG1), GSK-3alpha (GSK3A), or GSK-3beta (GSK3B) genes were detected. In contrast, mutations in the NH2-terminal regulatory domain of beta-catenin (CTNNB1) were found in 13 of 27 (48%) CR tumors lacking APC mutations. Mutations in the beta-catenin regulatory domain and APC were observed to be mutually exclusive, consistent with their equivalent effects on beta-catenin stability and Tcf transactivation. In addition, we found that CTNNB1 mutations can occur in the early, adenomatous stage of CR neoplasia, as has been observed previously with APC mutations. These results suggest that CTNNB1 mutations can uniquely substitute for APC mutations in CR tumors and that beta-catenin signaling plays a critical role in CR tumorigenesis.

    Funded by: NCI NIH HHS: CA57345

    Cancer research 1998;58;6;1130-4

  • Beta-catenin mutations in cell lines established from human colorectal cancers.

    Ilyas M, Tomlinson IP, Rowan A, Pignatelli M and Bodmer WF

    Cancer Genetics and Immunology Laboratory, Imperial Cancer Research Fund, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, OX3 9DU, United Kingdom. ilyas@europa.lif.icnet.uk

    beta-catenin has functions as both an adhesion and a signaling molecule. Disruption of these functions through mutations of the beta-catenin gene (CTNNB1) may be important in the development of colorectal tumors. We examined the entire coding sequence of beta-catenin by reverse transcriptase-PCR (RT-PCR) and direct sequencing of 23 human colorectal cancer cell lines from 21 patients. In two cell lines, there was apparent instability of the beta-catenin mRNA. Five different mutations (26%) were found in the remaining 21cell lines (from 19 patients). A three-base deletion (codon 45) was identified in the cell line HCT 116, whereas cell lines SW 48, HCA 46, CACO 2, and Colo 201 each contained single-base missense mutations (codons 33, 183, 245, and 287, respectively). All 23 cell lines had full-length beta-catenin protein that was detectable by Western blotting and that coprecipitated with E-cadherin. In three of the cell lines with CTNNB1 mutations, complexes of beta-catenin with alpha-catenin and APC were detectable. In SW48 and HCA 46, however, we did not detect complexes of beta-catenin protein with alpha-catenin and APC, respectively. These results show that selection of CTNNB1 mutations occurs in up to 26% of colorectal cancers from which cell lines are derived. In these cases, mutation selection is probably for altered beta-catenin function, which may significantly alter intracellular signaling and intercellular adhesion and may serve as a complement to APC mutations in the early stages of tumorigenesis.

    Proceedings of the National Academy of Sciences of the United States of America 1997;94;19;10330-4

  • Stabilization of beta-catenin by genetic defects in melanoma cell lines.

    Rubinfeld B, Robbins P, El-Gamil M, Albert I, Porfiri E and Polakis P

    Onyx Pharmaceuticals, 3031 Research Drive, Richmond, CA 94806, USA.

    Signal transduction by beta-catenin involves its posttranslational stabilization and downstream coupling to the Lef and Tcf transcription factors. Abnormally high amounts of beta-catenin were detected in 7 of 26 human melanoma cell lines. Unusual messenger RNA splicing and missense mutations in the beta-catenin gene (CTNNB1) that result in stabilization of the protein were identified in six of the lines, and the adenomatous polyposis coli tumor suppressor protein (APC) was altered or missing in two others. In the APC-deficient cells, ectopic expression of wild-type APC eliminated the excess beta-catenin. Cells with stabilized beta-catenin contained a constitutive beta-catenin-Lef-1 complex. Thus, genetic defects that result in up-regulation of beta-catenin may play a role in melanoma progression.

    Funded by: NCI NIH HHS: 1R43CA69931

    Science (New York, N.Y.) 1997;275;5307;1790-2

Literature (835)

Pubmed - human_disease

  • Absence of stabilizing mutations of beta-catenin encoded by CTNNB1 exon 3 in a large series of sporadic parathyroid adenomas.

    Costa-Guda J and Arnold A

    Center for Molecular Medicine, University of Connecticut School of Medicine, 263 Farmington Avenue, Farmington, Connecticut 06030-3101, USA.

    Context: The molecular mechanisms underlying the pathogenesis of sporadic parathyroid adenomas are incompletely understood. Dysfunction of the Wnt signaling pathway is an established pathogenetic contributor to human tumorigenesis and, recently, the role of stabilizing mutations in beta-catenin, a cause of abnormal Wnt signaling, has been examined in parathyroid tumors with conflicting results.

    Objective: The objective of the present study was to determine the frequency of stabilizing mutations in exon 3 of CTNNB1, encoding beta-catenin, in a large series of parathyroid adenomas.

    Ninety-seven sporadic parathyroid adenomas were examined for mutations in exon 3 of CTNNB1 by direct DNA sequencing.

    Results: No mutations were identified in any of the adenomas.

    Conclusions: The absence of stabilizing mutations of beta-catenin, including the previously reported S37A, encoded in CTNNB1 exon 3 among 97 tumors suggests that such mutations contribute rarely if at all to the development of sporadic parathyroid adenomas. A primary role for abnormal Wnt signaling in parathyroid tumor formation remains to be established.

    Funded by: NIDCR NIH HHS: 5T32-DE07302

    The Journal of clinical endocrinology and metabolism 2007;92;4;1564-6

  • Homozygous PMS2 deletion causes a severe colorectal cancer and multiple adenoma phenotype without extraintestinal cancer.

    Will O, Carvajal-Carmona LG, Gorman P, Howarth KM, Jones AM, Polanco-Echeverry GM, Chinaleong JA, Günther T, Silver A, Clark SK and Tomlinson I

    Molecular and Population Genetics Laboratory, London Research Institute, Cancer Research, London, UK.

    We report a patient of Indian descent with parental consanguinity, who developed 10 carcinomas and 35 adenomatous polyps at age 23 and duodenal adenocarcinoma at age 25. He also had dysmorphic features, mental retardation, and café-au-lait spots but no brain tumor. We aimed to establish his molecular diagnosis.

    Methods: Germ-line screening for APC and MYH/MUTYH mutations was normal as was immunohistochemistry for MLH1 and MSH2 proteins. Investigation by array-comparative genomic hybridization revealed deletion of a small region on chromosome 7. Using polymerase chain reaction, this region was refined to a 400-kilobase deletion, which included exons 9-15 of the PMS2 gene, and all coding regions of oncomodulin, TRIAD3, and FSCN1.

    Results: The deletion was confirmed as homozygous, and both parents were carriers. Immunohistochemistry showed absent PMS2 expression in all tumors and normal tissue. Most tumors showed microsatellite instability, more marked at dinucleotide than mononucleotide repeats. The tumors harbored no somatic mutations in APC, BRAF, AXIN2, or beta-catenin, but KRAS2 and TGFBR2 mutations were found.

    Conclusions: Our patient represents a novel phenotype for homozygous PMS2 mutation and perhaps the most severe colorectal cancer phenotype-in terms of numbers of malignancies at an early age-described to date. PMS2 mutations-and perhaps other homozygous mismatch repair mutations-should be considered in any patient presenting with multiple gastrointestinal tumors, since our patient could not be distinguished clinically from cases with attenuated familial adenomatous polyposis or MUTYH-associated polyposis.

    Gastroenterology 2007;132;2;527-30

  • Analysis of somatic APC mutations in rare extracolonic tumors of patients with familial adenomatous polyposis coli.

    Bläker H, Sutter C, Kadmon M, Otto HF, Von Knebel-Doeberitz M, Gebert J and Helmke BM

    Institute of Pathology, University of Heidelberg, Heidelberg, Germany. Hendrik_Blaeker@med.uni-heidelberg.de

    Patients with familial adenomatous polyposis coli (FAP) carry heterozygous mutations of the APC gene. At a young age, these patients develop multiple colorectal adenomas that consistently display a second somatic mutation in the remaining APC wild-type allele. Inactivation of APC leads to impaired degradation of beta-catenin, thereby promoting continuous cell-cycle progression. The role of APC inactivation in rare extracolonic tumors of FAP patients has not been characterized sufficiently. Among tissue specimen from 174 patients with known APC germ-line mutations, we identified 8 tumors infrequently seen in FAP. To investigate the pathogenic role of APC pathway deregulation in these lesions, they were analyzed for second-hit somatic mutations in the mutational cluster region of the APC gene. Immunohistochemistry was performed to compare the expression pattern of beta-catenin to the mutational status of the APC gene. Exon 3 of the beta-catenin gene (CTNNB1) was analyzed for activating mutations to investigate alternative mechanisms of elevated beta-catenin concentration. Although CTNNB1 mutations were not observed, second somatic APC mutations were found in 4 of the 8 tumors: a uterine adenocarcinoma, a hepatocellular adenoma, an adrenocortical adenoma, and an epidermal cyst. These tumors showed an elevated concentration of beta-catenin. No APC mutations were seen in focal nodular hyperplasia of the liver, angiofibrolipoma, and seborrheic wart. This is the first study reporting second somatic APC mutations in FAP-associated uterine adenocarcinoma and epidermal cysts. Furthermore, our data strengthen a role for impaired APC function in the pathogenesis of adrenal and hepatic neoplasms in FAP patients.

    Genes, chromosomes & cancer 2004;41;2;93-8

  • Genetic and epigenetic alterations of the APC gene in malignant melanoma.

    Worm J, Christensen C, Grønbaek K, Tulchinsky E and Guldberg P

    Institute of Cancer Biology, Danish Cancer Society, Strandboulevarden 49, DK-2100 Copenhagen, Denmark.

    High levels of beta-catenin and activating mutations in the beta-catenin gene (CTNNB1) have been demonstrated in malignant melanomas, implicating dysregulated Wnt signalling in the pathogenesis of this malignancy. We systematically examined melanoma cell lines for activating CTNNB1 mutations as well as genetic and epigenetic alterations of the adenomatous polyposis coli gene (APC), another key component of the Wnt signalling transduction pathway. Of 40 cell lines tested, one carried a truncating APC mutation and loss of the corresponding wild-type allele, and one carried a CTNNB1 missense mutation. Hypermethylation of APC promoter 1A was present in five of the cell lines (13%) and in nine of 54 melanoma biopsies (17%). Cells with truncating APC or activating CTNNB1 mutations showed increased transcription from endogenous and ectopic beta-catenin/T-cell factor (Tcf)-responsive target genes, consistent with the known effects of these alterations on beta-catenin stability and Tcf transactivation. In contrast, cell lines with APC promoter 1A hypermethylation did not show increased Wnt signalling, probably due to residual APC activity expressed from promoter 1B. Suppression of APC transcripts in melanoma cells by stable expression of short hairpin RNAs led to a Wnt signalling-independent increase in cell proliferation, but also reduced the invasive growth in collagen type I. Collectively, our data suggest that the tumour-suppressive function of APC in melanocytic cells is dose dependent. We propose that epigenetic silencing of promoter 1A may contribute to the development of malignant melanoma by reducing the expression of APC to a level that promotes cell proliferation without compromising the invasive capacity.

    Oncogene 2004;23;30;5215-26

  • APC haploinsufficiency, but not CTNNB1 or CDH1 gene mutations, accounts for a fraction of familial adenomatous polyposis patients without APC truncating mutations.

    Venesio T, Balsamo A, Rondo-Spaudo M, Varesco L, Risio M and Ranzani GN

    Unit of Pathology, Institute for Cancer Research and Treatment, Candiolo-Torino, Genova, Italy.

    Familial adenomatous polyposis (FAP) is an autosomal dominant condition characterized by the development of hundreds to thousands of colorectal adenomatous polyps. In addition to the classic form, there is also attenuated polyposis (attenuated adenomatous polyposis coli; AAPC), which is characterized by a milder phenotype. FAP/AAPC is caused by germline mutations in the adenomatous polyposis coli (APC) gene. Very recently, germline mutations in the base-excision repair gene MYH have been associated with recessive inheritance of multiple colorectal adenomas in a subset of patients. APC pathogenic alterations are mostly (>95%) represented by frameshift or nonsense mutations leading to the synthesis of a truncated protein. We identified 20 APC truncating mutation carriers out of 30 FAP/AAPC patients from different Italian kindreds. In the remaining 10 patients, we searched for alterations other than truncating mutations by enzymatic mutation detection, real-time quantitative RT-PCR, and genotyping of polymorphic markers encompassing the APC locus. Moreover, to assess whether mutations of genes interacting with APC can substitute or act in association with APC alterations, we sequenced both CTNNB1 (beta-catenin) and CDH1 (E-cadherin) genes. No CTNNB1 or CDH1 mutations were found. On the contrary, four patients showed a reduced APC gene expression compared with healthy subjects. In three of the four cases, genotyping results were compatible with a constitutive allelic deletion. In one case this conclusion was confirmed by haplotype segregation analysis. Our results support the notion that FAP/AAPC can result from APC constitutive haploinsufficiency, with gene deletion being a possible cause of reduced gene expression.

    Laboratory investigation; a journal of technical methods and pathology 2003;83;12;1859-66

  • Cribriform-morular variant of papillary thyroid carcinoma: a pathological and molecular genetic study with evidence of frequent somatic mutations in exon 3 of the beta-catenin gene.

    Xu B, Yoshimoto K, Miyauchi A, Kuma S, Mizusawa N, Hirokawa M and Sano T

    Department of Pathology, University of Tokushima School of Medicine, Tokushima 770-8503, Japan. xubing@basic.med.tokushima-u.ac.jp

    The cribriform-morular variant (C-MV), an unusual and peculiar subtype of papillary thyroid carcinoma (PTC), has been observed frequently in familial adenomatous polyposis (FAP)-associated thyroid carcinoma and also in sporadic thyroid carcinoma. In this paper, five young women with the C-MV of PTC, aged 22-34 years at cancer diagnosis, are reported; two of them had attenuated FAP. Grossly, one FAP-associated tumour and one sporadic tumour were multicentric and the others were solitary. Histologically, the tumours were encapsulated and exhibited a combination of cribriform, follicular, trabecular, solid, and papillary patterns of growth, with morular areas. Immunohistochemically, the tumour cells showed cytoplasmic expression of thyroglobulin, neuron-specific enolase, epithelial membrane antigen, high- and low-molecular-weight cytokeratins, vimentin, and bcl-2 protein; nuclear expression of oestrogen and progesterone receptors, and retinoblastoma protein; and cytoplasmic and nuclear accumulation of beta-catenin. Germline mutations of the adenomatous polyposis coli (APC) gene were investigated using the protein truncation test in four subjects, including two FAP individuals. Germline APC mutation was identified in only one FAP patient with the multicentric C-MV of PTC, who had a thymidine deletion at codon 512, resulting in a frameshift leading to a premature stop codon. No loss of heterozygosity of loci close to the APC gene was detected in tumour tissues from these four patients. Somatic mutation analysis of exon 3 of the beta-catenin gene (CTNNB1) revealed alterations in seven tumours from all five individuals: one at a serine residue (codon 29), three at amino acids adjacent to serine or threonine residues (codons 22, 39, and 44), and three at other amino acids (codons 49, 54, and 56). Moreover, each of two different tumours examined from two patients with the multicentric C-MV of PTC, had different somatic mutations of the CTNNB1 gene. Taken together, these data suggest that accumulation of mutant beta-catenin contributes to the development of the C-MV of PTC.

    The Journal of pathology 2003;199;1;58-67

  • Predominance of CIN versus MSI in the development of rectal cancer at young age.

    Fernebro E, Halvarsson B, Baldetorp B and Nilbert M

    Department of Oncology, University Hospital, Lund, Sweden. Eva.Fernebro@onk.lu.se

    Background: Development of proximal and distal colorectal cancers involve partly different mechanisms associated with the microsatellite instability (MSI) and the chromosomal instability (CIN) pathways. Colorectal cancers in patients under 50 years of age represent about 5% of the total number of tumors and have been associated with an increased frequency of MSI tumors. However, MSI and CIN may play different roles in the development of colon cancer and rectal cancer, and we have specifically investigated their contribution to the development of rectal cancer at young age.

    Methods: Thirty rectal cancers diagnosed before the age of 50 were characterized for DNA-ploidy, MSI, mutations of KRAS and CTNNB1 and immunohistochemical expression of p53, beta-catenin and of the mismatch repair (MMR) proteins MLH1 and MSH2.

    Results: DNA aneuploidy was detected in 21/30 tumors, KRAS mutations in 6 tumors, no mutations of CTNNB1 were detected but immunohistochemical staining for beta-catenin showed nuclear staining in 6 tumors, and immunohistochemical expression of p53 was detected in 18 tumors. MSI was detected in 3/30 tumors, all of which showed and immunohistochemical loss of staining for the MMR protein MSH2, which strongly indicates a phenotype associated with hereditary nonpolyposis colorectal cancer (HNPCC).

    Conclusions: MSI occurs only in a small fraction of the tumors from young patients with rectal cancer, but when present it strongly indicates an underlying HNPCC-causing mutation, and other mechanisms than HNPCC thus cause rectal cancer in the majority of young patients.

    BMC cancer 2002;2;25

  • APC and CTNNB1 mutations in a large series of sporadic colorectal carcinomas stratified by the microsatellite instability status.

    Løvig T, Meling GI, Diep CB, Thorstensen L, Norheim Andersen S, Lothe RA and Rognum TO

    Institute of Forensic Medicine, The National Hospital, University of Oslo, Norway. tone.lovig@labmed.uio.no

    Background: Adenomatous polyposis coli (APC) and beta-catenin (encoded by CTNNB1) are important components in the WNT signalling pathway, a pathway altered in nearly all colorectal tumours. Conflicting results are reported on whether APC mutations are less common in tumours with a high degree of microsatellite instability (MSI-H) than in microsatellite stable (MSS) ones, and whether mutations in the regulatory domain of CTNNB1 substitute for APC mutations in the MSI-H tumours.

    Methods: A consecutive series of 218 primary colorectal carcinomas, stratified by MSI status, were analysed for mutations in the APC gene (by the protein truncation test) and in the CTNNB1 gene (by single-strand conformation polymorphism).

    Results: APC mutations detected in 66% of the patients were significantly more frequent in the MSS and MSI-L (low) tumours than in the MSI-H tumour group (P < 0.001). The MSI-H tumours tended to have more frameshift mutations than the MSS/MSI-L tumours. The majority of the APC mutations were located in the mutation cluster region (MCR). Patients that had lost all beta-catenin binding sites of the APC gene showed a shorter survival time than patients who retained some or all of these binding sites (P = 0.045). Two mutations were found in the CTNNB1 gene, but neither of them was located in the regulatory domain in exon 3.

    Conclusion: This study confirms that APC mutations are less frequent in MSI-H tumours than in MSS and MSI-L tumours. However, CTNNB1 mutations do not substitute for APC mutations in MSI-H tumours in these Norwegian patients.

    Scandinavian journal of gastroenterology 2002;37;10;1184-93

  • No evidence for involvement of beta-catenin and APC in urothelial carcinomas.

    Stoehr R, Krieg RC, Knuechel R, Hofstaedter F, Pilarsky C, Zaak D, Schmitt R and Hartmann A

    Institute of Pathology, University of Regensburg, 93042 Regensburg, Germany.

    The wnt pathway plays an important role in embryonal patterning and cell fate determination, involving stabilization of nuclear and cytoplasmic beta-catenin (CTNNB1) mediated by APC, axin, and other proteins. Uncomplexed beta-catenin binds to TCF/LEF transcription factors and activates the expression of growth regulatory target genes such as c-myc or cyclin D1. In colorectal and other cancers, constitutive wnt signaling results frequently from mutations in one or more pathway components, e.g. APC and beta-catenin, resulting in nuclear and/or cytoplasmic accumulation of beta-catenin. In the present study, the most frequent alterations in the CTNNB1 and APC genes were investigated in primary urothelial bladder tumors and cell lines. Snap-frozen bladder tumors (n=99) of different stages and grades and 4 cell lines (RT4, RT112, J82, UROtsa) were investigated for APC allelic deletions by loss of heterozygosity (LOH) analysis. The most frequent mutated regions of CTNNB1 (degradation box in the third exon) and APC (mutation cluster region) were directly sequenced. Beta-catenin expression was analyzed by immunofluorescence in the cell lines. LOH at the APC gene locus on chromosome 5q21 was found in 7 of 72 (10%) of the informative cases. No mutations were found in either CTNNB1 or APC. A previously described polymorphism at codon 1493 of the APC gene was detected in 8 tumors and 3 cell lines. All cell lines showed normal membranous beta-catenin staining without evidence for nuclear or cytoplasmic accumulation. Alteration of APC and beta-catenin, which are the most frequent wnt pathway alterations in many tumor types, are rare events in urothelial carcinomas. Other wnt pathway members, such as axin, may play an important role in urothelial carcinogenesis.

    International journal of oncology 2002;20;5;905-11

  • Loss of membranous expression of beta-catenin is associated with tumor progression in cutaneous melanoma and rarely caused by exon 3 mutations.

    Demunter A, Libbrecht L, Degreef H, De Wolf-Peeters C and van den Oord JJ

    Department of Pathology, Laboratory of Morphology and Molecular Pathology, University Hospitals, Katholieke Universiteit Leuven, Belgium. anouk.demunter@uz.kuleuven.ac.be

    beta-Catenin plays a fundamental role in the regulation of the E-cadherin-catenin cell adhesion complex. It also plays a role in the Wnt signaling pathway by activating T-cell factor- and lymphoid enhancer factor-regulated gene transcription. The level of beta-catenin in cells is tightly controlled in a multiprotein complex, and mutations in the glycogen synthase kinase 3beta (GSK-3beta) phosphorylation sites of the beta-catenin gene (CTNNB1) result in nuclear and/or cytoplasmic accumulation of beta-catenin and constitutive transactivation of T-cell factor and lymphoid enhancer factor target genes, a mechanism occurring in many cancers. Melanoma cell lines may harbor beta-catenin mutations; in vivo, however, cellular accumulation of beta-catenin is rarely caused by CTNNB1 mutations. In our study, 43 primary cutaneous melanoma and 30 metastases were screened for CTNNB1 exon 3 mutations by using a denaturing gradient gel electrophoresis technique and sequencing. beta-Catenin mutations were found in 2 primary melanomas and 1 metastatic melanoma and were not correlated with nuclear accumulation of beta-catenin in these cases. Cellular expression of beta-catenin was evaluated by immunohistochemistry and by reverse polymerase chain reaction (RT-PCR) in 80 and 70 cases, respectively. Immunohistochemistry revealed a significant loss of membranous beta-catenin staining between the primary and metastatic melanomas as well as between radial and vertical growth phase. RT-PCR showed a significant inverse correlation between the amount of RNA and the proportion of cells with membranous expression of beta-catenin (P =.0015); no correlation existed between the amount of RNA and the number of cells with nuclear or cytoplasmic expression of beta-catenin. In conclusion, nuclear expression of beta-catenin is seen in cutaneous melanoma but, in contrast to the case of many other cancers, does not correlate with tumor stage or mutation status. A combination of immunohistochemistry and RT-PCR showed that down-regulation of membranous beta-catenin was associated with an increased amount of beta-catenin RNA in primary or metastatic melanoma. Our results suggest that posttranslational events, rather than CTNNB1 mutations, are responsible for the altered distribution of beta-catenin in cutaneous melanoma.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2002;15;4;454-61

  • Diverse mechanisms of beta-catenin deregulation in ovarian endometrioid adenocarcinomas.

    Wu R, Zhai Y, Fearon ER and Cho KR

    Department of Pathology, The University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA.

    Clinical and molecular findings suggest that the four major histological subtypes of ovarian carcinoma (serous, clear cell, mucinous, and endometrioid) likely represent distinct disease entities. Prior studies have shown that ovarian endometrioid adenocarcinomas (OEAs) often carry mutations in the CTNNB1 gene, which encodes beta-catenin, a critical component of the Wnt signaling pathway. However, the nature of other defects in the Wnt signaling pathway in ovarian carcinomas remains largely unknown. Thus, in 45 primary OEAs and two OEA-derived cell lines, we sought to comprehensively address the prevalence of and mechanisms underlying beta-catenin and Wnt pathway deregulation. CTNNB1 missense mutations were detected in 14 primary tumors. All mutations affected the NH(2)-terminal regulatory domain of beta-catenin, presumably rendering the mutant proteins resistant to degradation. Immunohistochemical studies revealed nuclear accumulation of beta-catenin in all but two tumors with CTNNB1 mutations. Two primary tumors lacking CTNNBI mutations showed strong nuclear immunoreactivity for beta-catenin. In one of the two tumors, biallelic inactivation of the APC gene was found. In the remaining 29 primary OEAs, unequivocal nuclear beta-catenin immunoreactivity was not observed, though a nonsense mutation in AXIN1 was observed in one tumor and a truncating frameshift mutation in AXIN2 was seen in another case. Both OEA-derived cell lines studied (TOV-112D and MDAH-2774) had elevated constitutive T-cell factor/lymphoid enhancer factor transcriptional activity. TOV-112D cells were shown to harbor mutant beta-catenin, whereas a missense AXIN1 sequence alteration was identified in MDAH-2774 cells. Collectively, our findings demonstrate frequent defects of the Wnt signaling pathway in a particular subtype of ovarian carcinomas, i.e., OEAs. Although mutations in the CTNNB1 gene are the most common mechanism of beta-catenin deregulation in OEAs, beta-catenin deregulation may also result from mutations in the APC, AXIN1, and AXIN2 genes.

    Cancer research 2001;61;22;8247-55

  • Somatic mutations of WNT/wingless signaling pathway components in primitive neuroectodermal tumors.

    Koch A, Waha A, Tonn JC, Sörensen N, Berthold F, Wolter M, Reifenberger J, Hartmann W, Friedl W, Reifenberger G, Wiestler OD and Pietsch T

    Department of Neuropathology, University of Bonn Medical Center; Bonn, Germany.

    Primitive neuroectodermal tumors (PNETs) represent the most frequent malignant brain tumors in childhood. The majority of these neoplasms occur in the cerebellum and are classified as medulloblastomas (MB). Most PNETs develop sporadically; however, their incidence is highly elevated in patients carrying germline APC gene mutations. The APC gene encodes a central component of the WNT/wingless developmental signaling pathway. It regulates the levels of cytoplasmic beta-catenin protein that plays a central role in neural development and cell proliferation. We analyzed 87 sporadic PNETs and 10 PNET cell lines for mutations of the APC gene and beta-catenin (CTNNB1) gene using single strand conformational polymorphism (SSCP) and sequencing analysis. We examined the mutation cluster region of APC (codons 1255--1641) for germline variants and somatic mutations. The medulloblastoma cell line MHH-MED-2 carried a Glu1317Gln missense germline variant and a sporadic MB sample showed a somatic Pro1319Leu substitution. Mutational analysis of exon 3 of CTNNB1 uncovered 4 PNETs (4.8%) with somatic missense mutations. These mutations caused amino acid substitutions in 3 of 80 medulloblastomas (Ser33Phe, Ser33Cys and Ser37Cys) and 1 of 4 supratentorial PNETs (Gly34Val). All mutations affected GSK-3 beta phosphorylation sites of the degradation targeting box of beta-catenin and resulted in nuclear beta-catenin protein accumulation. Deletions of CTNNB1 were not detected by PCR amplification with primers spanning exons 1--5. Our data indicate that inappropriate activation of the WNT/wingless signaling pathway by mutations of its components may contribute to the pathogenesis of a subset of PNETs.

    International journal of cancer 2001;93;3;445-9

  • Genetic alteration of the beta-catenin gene (CTNNB1) in human lung cancer and malignant mesothelioma and identification of a new 3p21.3 homozygous deletion.

    Shigemitsu K, Sekido Y, Usami N, Mori S, Sato M, Horio Y, Hasegawa Y, Bader SA, Gazdar AF, Minna JD, Hida T, Yoshioka H, Imaizumi M, Ueda Y, Takahashi M and Shimokata K

    Department of Thoracic Surgery, Nagoya University School of Medicine, Nagoya 466-8550, Japan.

    The beta-catenin gene (CTNNB1) has been shown to be genetically mutated in various human malignancies. To determine whether the beta-catenin gene is responsible for oncogenesis in thoracic malignancies, we searched for the mutation in 166 lung cancers (90 primary tumors and 76 cell lines), one blastoma and 10 malignant mesotheliomas (two primary tumors and eight cell lines). Among the lung cancers, including 43 small cell lung cancers (SCLCs) and 123 non-small cell lung cancers (NSCLCs), we identified four alterations in exon 3, which is the target region of mutation for stabilizing beta-catenin. One primary adenocarcinoma had a somatic mutation from C to G, leading to an amino acid substitution from Ser to Cys at codon 37. Among the cell lines, SCLC NCI-H1092 had a mutation from A to G, leading to an Asp to Gly substitution at codon 6, NSCLC HCC15 had a mutation from C to T, leading to a Ser to Phe substitution at codon 45, and NSCLC NCI-H358 had a mutation from A to G, leading to a Thr to Ala substitution at codon 75. One blastoma also had a somatic mutation from C to G, leading to a Ser to Cys substitution at codon 37. Among the 10 malignant mesotheliomas, we identified a homozygous deletion in the NCI-H28 cell line. Cloning of the rearranged fragment from NCI-H28 indicated that all the exons except exon 1 of the beta-catenin gene are deleted and that the deletion junction is 13 kb downstream from exon 1. Furthermore, Northern blot analysis of 26 lung cancer and eight mesothelioma cell line RNAs detected ubiquitous expression of the beta-catenin messages except NCI-H28, although Western blot analysis showed that relatively less amounts of protein products were expressed in some of lung cancer cell lines. Our findings suggest that the beta-catenin gene is infrequently mutated in lung cancer and that the NCI-H28 homozygous deletion of the beta-catenin gene might indicate the possibility of a new tumor suppressor gene residing in this region at 3p21.3, where various types of human cancers show frequent allelic loss.

    Funded by: NCI NIH HHS: CA71618, P50 CA70907

    Oncogene 2001;20;31;4249-57

  • Beta-catenin activation through mutation is rare in rectal cancer.

    Nilbert M and Rambech E

    Department of Oncology, University Hospital, 221 85 Lund, Sweden. mef.nilbert@onk.lu.se

    Increased transcriptional activation through beta-catenin stabilization plays a central role in colorectal tumorigenesis. Alterations of phosphorylation sites within the CTNNB1 gene, which codes for beta-catenin has been reported to occur in about one-half of colorectal tumors without APC-gene mutations. We assessed the importance of mutations in the regulatory domain, located within exon 3 of CTNNB1, in 103 rectal carcinomas and correlated these data with presence of microsatellite instability, somatic frame-shift alterations of the TCF-4 gene, and APC-gene mutations in the tumors. No mutation was detected in exon 3 of the CTNNB1 gene and our results thus demonstrate that beta-catenin activation through mutation rarely contributes to the development of sporadic and microsatellite instability stable rectal cancer.

    Cancer genetics and cytogenetics 2001;128;1;43-5

  • beta-Catenin gene mutation in human hair follicle-related tumors.

    Kajino Y, Yamaguchi A, Hashimoto N, Matsuura A, Sato N and Kikuchi K

    Department of Laboratory Medicine, Shiga University of Medical Science, Ohtsu, Japan.

    beta-Catenin, a multifunctional protein related to the adherens junction and to signal transduction, is a key molecule of cell proliferation, and it is central to epithelial architecture, regulating the polarity of cells and tissues. beta-Catenin stabilization may play a key role in epidermal signaling leading to hair development, and its aberrant activation may be implicated in formation of hair tumors. Several investigators have shown that pilomatricomas are frequently associated with beta-catenin mutation. In this study, we confirmed beta-catenin gene (CTNNB1) mutation in human pilomatricomas (100% frequency) from which adequate DNA could be obtained for gene analysis. A novel mutation, D32N, was found in one case of pilomatricoma. A preliminary immunohistological study revealed prominent beta-catenin staining in basophilic cells of pilomatricomas, especially in nuclei. Benign tumors which were considered to be derived from hair matrix or hair follicles, and other benign skin tumors, were also investigated. beta-Catenin mutations were not detected in any of the these tumors. These results seem to indicate that hair matrix cells are key players in hair development. Investigation into gene abnormalities of hair-follicle tumors may elucidate the cause of their neoplastic transformation, and may provide a suggestion for the mechanism of hair development.

    Pathology international 2001;51;7;543-8

  • Cytoplasmic and nuclear accumulation of beta-catenin is rarely caused by CTNNB1 exon 3 mutations in cutaneous malignant melanoma.

    Omholt K, Platz A, Ringborg U and Hansson J

    Cancer Centre Karolinska, Department of Oncology-Pathology, Radiumhemmet, Karolinska Hospital, Stockholm, Sweden.

    Beta-catenin plays an important role in the Wnt signaling pathway by activating T-cell factor (Tcf)/lymphoid enhancer factor (Lef)-regulated gene transcription. The level of beta-catenin is regulated through GSK-3beta phosphorylation of specific serine and threonine residues, all of which are encoded for in exon 3 of the beta-catenin gene (CTNNB1). Mutations altering the GSK-3beta phosphorylation sites lead to cellular accumulation of beta-catenin and constitutive transcription of Tcf/Lef target genes. Such mutations have previously been found in melanoma cell lines. In our study, primary melanomas and their corresponding metastases were screened for CTNNB1 exon 3 mutations using single-strand conformation polymorphism and nucleotide sequence analysis. One of 31 primary tumors and 1 of 37 metastases, both originating from the same patient, had a TCT to TTT mutation at codon 45, changing serine to phenylalanine. Immunohistochemical analysis revealed membranous localization of beta-catenin in a majority of the samples. The mutated primary tumor and metastasis, however, displayed widespread cytoplasmic and nuclear expression of beta-catenin. An additional 30% of the primary tumors showed focal cytoplasmic and nuclear staining. Thus, beta-catenin exon 3 mutations are rare in primary as well as metastatic melanomas and do not explain the abnormal cytoplasmic and nuclear localization of beta-catenin found in a relatively large fraction of primary melanomas.

    International journal of cancer 2001;92;6;839-42

  • CTNNB1 mutations and beta-catenin protein accumulation in human hepatocellular carcinomas associated with high exposure to aflatoxin B1.

    Devereux TR, Stern MC, Flake GP, Yu MC, Zhang ZQ, London SJ and Taylor JA

    Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina 27709, USA.

    beta-Catenin plays a key role in the Wnt signaling pathway, and mutations of CTNNB1, the gene that encodes beta-catenin, have been identified in about one-fourth of human hepatocellular carcinomas from regions of low aflatoxin B1 exposure. In this study 62 hepatocellular carcinomas (HCCs) from people highly exposed to aflatoxin B1 in Guangxi, People's Republic of China, were laser-capture microdissected and examined for CTNNB1 mutations. In addition, 41 of the HCCs were evaluated for the presence of the beta-catenin protein by immunohistochemical methods. Twenty of the HCCs showed positive results for beta-catenin, with strong membrane staining, while adjacent non-neoplastic liver tissue lacked or showed only weak membrane staining. One HCC, in which a CTNNB1 mutation was not detected, showed nuclear staining for the beta-catenin protein. Mutations of CTNNB1 were identified in five HCCs. These consisted of four point mutations in the glycogen serine kinase-3beta phosphorylation region of codons 32-45 and one deletion of codons 32-38. These mutations were similar to those previously reported for human HCC, although at a lower frequency. A signature mutation profile associated with aflatoxin B1 exposure could not be identified. The immunohistochemical findings indicate a role for accumulation of beta-catenin and possibly increased Wnt signaling in aflatoxin B1-associated HCC. The low frequency of CTNNB1 mutations, however, suggests that mutation of another Wnt signaling component, such as the Wnt scaffolding protein axin or the adenomatous polyposis coli protein, both of which modulate beta-catenin stability, also may be involved in aflatoxin-associated HCC. Published 2001 Wiley-Liss, Inc.

    Funded by: NCI NIH HHS: R35 CA 53890

    Molecular carcinogenesis 2001;31;2;68-73

  • Beta-catenin dysregulation in thyroid neoplasms: down-regulation, aberrant nuclear expression, and CTNNB1 exon 3 mutations are markers for aggressive tumor phenotypes and poor prognosis.

    Garcia-Rostan G, Camp RL, Herrero A, Carcangiu ML, Rimm DL and Tallini G

    Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA. ggarcia@cnio.es

    beta-catenin has a role in cell adhesion and Wnt signaling. It is mutated or otherwise dysregulated in a variety of human cancers. In this study we assess beta-catenin alteration in 145 thyroid tumors samples from 127 patients. beta-catenin was localized using immunofluorescence and mutational analysis was performed by single-strand conformational polymorphism. Membrane beta-catenin expression was decreased in eight of 12 (66%) adenomas and in all 115 carcinomas (P: < 0.0001). Among carcinomas, reduced membrane beta-catenin was associated with progressive loss of tumor differentiation (P: < 0.0001). CTNNB1 exon 3 mutations and nuclear beta-catenin localization were restricted to poorly differentiated [7 of 28 (25%) and 6 of 28 cases (21.4%), respectively] or undifferentiated carcinomas [19 of 29 (65.5%) and 14 of 29 (48.3%) cases, respectively]. Poorly differentiated tumors always featured mutations involving Ser and Thr residues and were characterized by Thr to Ile amino acid substitutions (P: = 0.0283). The association between CTNNB1 exon 3 mutations and aberrant nuclear immunoreactivity (P: = 0.0020) is consistent with Wnt activation because of stabilizing beta-catenin mutations. Low membrane beta-catenin expression as well as its nuclear localization or CTNNB1 exon 3 mutations are significantly associated with poor prognosis, independent of conventional prognostic indicators for thyroid cancer but not of tumor differentiation. Analysis of beta-catenin dysregulation may be useful to objectively subtype thyroid neoplasms and more accurately predict outcomes.

    The American journal of pathology 2001;158;3;987-96

  • Constitutive activation of the Wnt signaling pathway by CTNNB1 (beta-catenin) mutations in a subset of human lung adenocarcinoma.

    Sunaga N, Kohno T, Kolligs FT, Fearon ER, Saito R and Yokota J

    Biology Division, National Cancer Center Research Institute, Tokyo, Japan.

    Constitutive activation of the Wnt signaling pathway as a result of genetic alterations of APC, AXIN1, and CTNNB1 has been found in various human cancers, including those of the colon, liver, endometrium, ovary, prostate, and stomach. To investigate the pathogenetic significance of constitutive activation of the Wnt signaling pathway in human lung carcinogenesis, CTNNB1 alterations in exon 3, a region known to represent a mutation hot spot, were screened in 46 lung cancer cell lines and 47 primary lung cancers. Missense mutations causing substitutions of Ser/Thr residues critical for regulation by GSK-3beta were detected in one (2%) of the cell lines, A427, and two (4%) of the surgical specimens. The three lung cancers with CTNNB1 mutations were adenocarcinomas. To explore the prevalence of constitutive activation of the Wnt signaling pathway in human lung cancer, we assessed 15 lung cancer cell lines representing major histological subtypes of lung cancers for constitutive Tcf transcriptional activity (CTTA). CTTA was observed only in the A427 adenocarcinoma cell line, but not in the remaining 14 cell lines. The data indicate that constitutive activation of the Wnt signaling pathway caused by CTNNB1 mutation is involved in the development and/or progression of a subset of lung carcinoma, preferentially in adenocarcinoma.

    Genes, chromosomes & cancer 2001;30;3;316-21

  • Mutational analysis of the CTNNB1 and APC genes in uterine endometrioid carcinoma.

    Schlosshauer PW, Pirog EC, Levine RL and Ellenson LH

    Department of Pathology, Joan and Sanford I. Weill Medical College of Cornell University, New York, USA.

    Despite recent studies, the molecular genetic events responsible for the development of uterine endometrioid carcinoma (UEC) remain incompletely characterized. Mutations in the beta-catenin (CTNNB1) gene have been recently reported in a small percentage of UECs and in the endometrioid variant of ovarian carcinoma suggesting that the Wnt signal transduction pathway is involved in the development of female genital tract tumors with endometrioid morphology. The Wnt pathway is a critical pathway in the development of colorectal cancer (CRC) with mutations occurring in the beta-catenin (CTNNB1) or adenomatous polyposis coli (APC) genes in 10 to 15% and 85% of cases, respectively. Because UEC and CRC share other molecular genetic alterations and histologic features and previous studies of UEC have not reported an analysis of the APC gene, we chose to further elucidate the role of the Wnt pathway in UEC. To this end, we analyzed 32 cases of UEC for mutations of the CTNNB1 and APC genes. Mutations of CTNNB1 were present in six of 32 (18%) cases: four grade 1 carcinomas, one grade 2, and one grade 3 carcinoma. Five missense mutations were identified, three involving Ser/Thr phosphorylation sites and two adjacent to a Ser phosphorylation site. One case contained a deletion encompassing codons 34 to 37, which includes a Ser phosphorylation site. No mutations resulting in truncation of the APC protein were found. Our results support a role for the Wnt signaling pathway via mutation of CTNNB1, but not APC, in the development of a subset of UECs.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2000;13;10;1066-71

  • [Mutation analysis of the beta-catenin gene in epithelial carcinomas of the ovaries].

    Tanyi J, Páy A, Rigó J, Nagy B and Papp Z

    Altalános Orvostudományi Kar, Semmelweis Egyetem, Budapest.

    beta-catenin is a continuously expressed cytoplasmic protein that has an important role is both E-cadherin-mediated cell-cell adhesion and in activation of Wnt/Wingless transcriptional pathway. The accumulation of stabilized beta-catenin caused by the mutation of the exon 3 of beta-catenin gene can stimulate the T-cell factor/Lymphoid enhancing factor-mediated transcriptional activation. The activation of transcriptional pathway may through oncogenes is an important step of the oncogenesis in solid tumors. In this study we analyzed mutations in exon 3 of the beta-catenin gene in 18 sporadic epithelial ovarian tumors. Three mutations were found from these 18 ovarian tumor samples which contained 8 serous, 3 mucinous, 5 endometrioid, one malignant Brenner-type tumor and one transitional cell carcinoma. Two mutations occurred in endometrioid-type (in 47 and 55 codons) and one in serous-type (in 47 codon) ovarian carcinomas, and both mutations were missense and somatic. The patients with mutated beta-catenin gene appeared from the younger patients under the age of 50. Our results suggest that the stabilization of beta-catenin protein by the mutation of CTNNB1 gene can contribute to the multistep process of the oncogenesis of epithelial ovarian tumors. Furthermore these mutations mostly occurs in the endometrioid-type of EOT, but can appear in other types such as serous-type ovarian tumor.

    Orvosi hetilap 2000;141;21;1115-9

  • Mutational analysis of the CTNNB1 (beta-catenin) gene in human endometrial cancer: frequent mutations at codon 34 that cause nuclear accumulation.

    Ikeda T, Yoshinaga K, Semba S, Kondo E, Ohmori H and Horii A

    Department of Molecular Pathology, Tohoku University School of Medicine, Sendai 980-8575, Japan.

    Recently, CTNNB1 (beta-catenin) has been found to function as an oncoprotein that works in the Wnt signaling pathway, and mutation of this gene has been reported in various human cancers. In this study, we analyzed 44 endometrial cancers and found somatic missense mutations in five (11%) tumors. Interestingly, four (80%) of the five tumors with mutations would cause amino acid alterations at residues next to Ser 33, one of the targets for phosphorylation of glycogen synthase kinase (GSK)-3beta. The tumors with mutations showed accumulation of the CTNNB1 protein in cytoplasm and nucleus. This is the first report of frequent somatic mutation of the CTNNB1 gene at codons adjacent to those encoding to Ser/Thr residues in endometrial cancer.

    Oncology reports 2000;7;2;323-6

  • [beta-Catenine as a genomic target of high-grade microsatellite instability in colorectal cancer].

    Kölble K, Barthel B, Ullrich O, Pidde H, Döhring C, Rüschoff J, Schlag PM and Dietel M

    Institut für Pathologie, Universitätsklinikum Charité, Humboldt-Universität, Berlin.

    Aims: Various inherited and acquired alterations affecting the genes and gene products of the WNT pathway appear to be involved in the different molecular routes leading to colorectal cancer (CRC). This study was initiated to investigate the prevalence of somatic mutations in the beta-catenin gene (CTNNB1) and the associated pathology in CRC with defective DNA mismatch repair.

    Methods: Paraffin and/or frozen sections of 33 primary CRC (including any liver and lymph node metastases present) with high-grade microsatellite instability (MSI-H; i.e. with > or = 5 unstable microsatellite markers of 10 tested) were polytopically fractionated by microdissection. Genomic and c-DNA samples were sequenced across exons 2-4 of CTNNB1 and the expression patterns of beta-catenin (beta-C) analyzed by immunohistology and Western blotting.

    Results: Seven somatic mutations affecting phosphorylation sites of exon 3 (2 deletions also encompassing parts of either intron 2 or exon 4 [delta X2/3 bzw. delta X3/4] and 5 missense mutations [2 x T41A, 2 x S45F, S45P]) were identified. Two mutations (delta X3/4 and S45F) were concordantly present in CRC primaries and their respective metastases whereas the S45P mutation was restricted to a hepatic metastasis. In the delta X2/3 CRC primary only a shortened 66 kD CTNNB1 gene product was present while its associated liver metastasis showed a total loss of beta-C expression.

    Conclusions: Both exon 3 and the entire locus coding for beta-C are somatically altered in approximately 20% of CRC with MSI-H at different stages of tumor progression. Thus CTNNB1 appears to be a genomic target for complex oncogenic mutations and deletional processes in a substantial fraction of this molecular subset of CRC.

    Verhandlungen der Deutschen Gesellschaft fur Pathologie 2000;84;182-6

  • beta-catenin mutation and expression analysis in ovarian cancer: exon 3 mutations and nuclear translocation in 16% of endometrioid tumours.

    Wright K, Wilson P, Morland S, Campbell I, Walsh M, Hurst T, Ward B, Cummings M and Chenevix-Trench G

    Joint Experimental Oncology Program, Queensland Institute of Medical Research and University of Queensland, Brisbane, Australia.

    The molecular mechanisms involved in the generation of epithelial ovarian cancers are poorly understood, but evidence suggests that the different histological subtypes may arise from independent tumorigenic events. beta-Catenin is emerging as an important oncogene in the transformation of a number of epithelial cancers, and mutations have been reported in a small study of endometrioid ovarian adenocarcinomas. Mutations in the NH(2)-regulatory domain of beta-catenin stabilise the cytoplasmic levels of this protein, which promotes up-regulation of the beta-catenin-T-cell factor-lymphoid enhancer factor transcriptional complex. We report here beta-catenin (CTNNB1) exon 3 mutation analysis in 149 epithelial ovarian carcinomas. This revealed 10/63 (16%) endometrioid ovarian tumours with activating mutations of the beta-catenin gene. All mutations were missense changes within the GSK3beta consensus site, affecting serine residues at codons 33 and 37 and glycine at codon 34. Immuno-histochemical analysis identified cytoplasmic stabilisation and nuclear translocation in those endometrioid tumours with mutations. This phenotypic change was also identified in 3 other endometrioid tumours that did not have somatic mutations within exon 3 of CTNNB1. Stabilisation of the free, monomeric pool of beta-catenin and the probable resulting constitutive activation of its Tcf-associated transcriptional complex appears to be a specific oncogenic event in endometrioid ovarian adenocarcinoma.

    International journal of cancer 1999;82;5;625-9

  • Germline mutations are frequent in the APC gene but absent in the beta-catenin gene in familial adenomatous polyposis patients.

    Cao X, Eu KW, Seow-Choen F and Cheah PY

    Department of Colorectal Surgery, Singapore General Hospital, Outram Road, Republic of Singapore.

    Inactivation of the adenomatous polyposis coli (APC) gene has been shown to initiate the majority of colorectal cancer (CRC), including a familial form called familial adenomatous polyposis (FAP). One consequence of the APC mutation is the activation of the beta-catenin (CTNNB1)/T-cell transcription factor (Tcf) pathway. A recent study has shown that about half of the sporadic CRC lacking APC mutation has CTNNB1 mutation, suggesting that CTNNB1 mutation can substitute for APC mutation in the initiation of colorectal tumorigenesis. However, the frequency of CTNNB1 germline mutation in FAP has not been reported. In the present study, we investigated the frequencies of APC and CTNNB1 germline mutations in 26 unrelated FAP families. We used the Protein Truncation Test (PTT) to screen the entire coding region of APC and found germline mutations in twenty families. We then screened for CTNNB1 germline mutations in the rest of the families lacking detectable APC mutations. No missense mutations at GSK-3beta phosphorylation sites or interstitial deletion of exon 3 of CTNNB1 was found. Our results indicate that APC germline mutations are frequent but CTNNB1 germline mutations are rare in FAP patients, suggesting that CTNNB1 mutation cannot substitute for APC mutation in the initiation of FAP. Genes Chromosomes Cancer 25:396-398, 1999.

    Genes, chromosomes & cancer 1999;25;4;396-8

  • Beta-catenin mutations are specific for colorectal carcinomas with microsatellite instability but occur in endometrial carcinomas irrespective of mutator pathway.

    Mirabelli-Primdahl L, Gryfe R, Kim H, Millar A, Luceri C, Dale D, Holowaty E, Bapat B, Gallinger S and Redston M

    Centre for Cancer Genetics, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.

    Some colorectal tumors with wild-type adenomatous polyposis coli gene have activating mutations in beta-catenin (encoded by CTNNB1) that result in decreased phosphorylation by GSK-3beta and increased signaling through the Tcf/Lef transcription factors. To investigate the relationship between CTNNB1 mutations and underlying pathways of genomic instability, we examined 80 colorectal cancers stratified by the presence or absence of microsatellite instability (MSI). CTNNB1 mutations were identified in 13 (25%) of 53 cancers with high frequency MSI (MSI-H), including 12 point mutations at exon 3 phosphorylation sites (codons 41 and 45) and one deletion of the entire exon 3 degradation box. No CTNNB1 mutations were identified in 27 microsatellite stable or low frequency MSI (MSI-L) colorectal cancers (P < 0.01). In contrast, CTNNB1 mutations were identified in 3 of 9 (33%) MSI-H and 10 of 20 (50%) MSS/MSI-L endometrial carcinomas, suggesting a more generalized involvement in these tumors. Only six (46%) of the endometrial carcinoma CTNNB1 mutations occurred at residues directly phosphorylated by GSK-3beta, and only one of these was at either codon 41 or 45. All point mutations in MSI-H cancers were transitions, whereas 64% of those in MSS/MSI-L cancers were transversions (P < 0.01). The differences in the mutation profiles suggest that there may be molecular fingerprints of CTNNB1 mutations, determined by biological factors related to both tumor type and underlying pathways of genomic instability.

    Cancer research 1999;59;14;3346-51

  • Beta-catenin mutations in human prostate cancer.

    Voeller HJ, Truica CI and Gelmann EP

    Division of Hematology/Oncology, Lombardi Cancer Center, Georgetown University School of Medicine, Washington, DC 20007-2197, USA.

    Beta-catenin plays essential roles in both intercellular adhesion and signal transduction. As a signaling molecule, beta-catenin supplies an activating domain to the T-cell factor/lymphoid enhancer-binding factor family of DNA-binding proteins and activates gene transcription. Posttranslational stabilization of beta-catenin, leading to elevated protein levels and constitutive gene activation, has been proposed as an important step in oncogenesis. Stabilization of beta-catenin can occur through mutation to highly conserved amino acids encoded in exon 3 of the beta-catenin gene (CTNNB1). To determine whether this pathway of malignant transformation is important in prostate cancer, we analyzed 104 prostate cancer tissue specimens, 4 prostate cancer cell lines, and 3 prostate tumor xenografts for activating mutations in exon 3 of CTNNB1. Mutations were detected in 5 of the 104 prostate cancer tissue samples. Four of the five mutations involved serine or threonine residues implicated in the degradation of beta-catenin. A fifth tumor had a mutation at codon 32, changing a highly conserved aspartic acid to a tyrosine. Mutational analysis of multiple regions from several tumor samples showed that the beta-catenin mutations were present focally and therefore may occur during tumor progression.

    Funded by: NCI NIH HHS: P30-CA-51008

    Cancer research 1998;58;12;2520-3

  • Mutations in the beta-catenin gene (CTNNB1) in endometrioid ovarian carcinomas.

    Palacios J and Gamallo C

    Departamento de Anatomía Patológica, Hospital Universitario La Paz (Universidad Autónoma de Madrid), Spain.

    Mutations of the beta-catenin gene (CTNNB1) have recently been implicated in the initiation of some colon carcinomas and melanomas. In these tumors, beta-catenin abnormally accumulates in the cell nuclei. In an ongoing immunohistochemical study of the cadherin-catenin complex protein expression in ovarian carcinomas, we observed beta-catenin in tumor cell nuclei in some cases; this prompted us to study whether or not this abnormal immunostaining pattern was due to mutation in the beta-catenin gene itself. This study examines beta-catenin immunohistochemical expression in 40 stage I and II ovarian borderline tumors and carcinomas of the most common histological types. Membrane expression was heterogeneous in all 40 cases. However, the cytoplasm and nucleus of five (one borderline tumor and four carcinomas) of the six endometrioid lesions contained beta-catenin expression. PCR and sequencing analyses of a 200-bp fragment of exon 3 of the CTNNB1 gene, encompassing the sequence for glycogen synthetase kinase-3beta phosphorylation, were performed in 11 tumors. Heterozygous substitution mutations at codon 37 in two cases (S37F and S37C) and at codon 41 in one case (T41A) were found in three endometrioid lesions (one borderline tumor and two carcinomas) with abnormal beta-catenin expression. Three endometrioid carcinomas and five tumors of other histological types analyzed showed normal DNA sequences. These results implicate beta-catenin gene mutations in ovarian malignant transformation with a characteristic phenotype: endometrioid ovarian carcinoma.

    Cancer research 1998;58;7;1344-7

  • Mutational analysis of the APC/beta-catenin/Tcf pathway in colorectal cancer.

    Sparks AB, Morin PJ, Vogelstein B and Kinzler KW

    Johns Hopkins Oncology Center, Baltimore, Maryland 21231, USA.

    Mutation of the adenomatous polyposis coli (APC) tumor suppressor gene initiates the majority of colorectal (CR) cancers. One consequence of this inactivation is constitutive activation of beta-catenin/Tcf-mediated transcription. To further explore the role of the APC/beta-catenin/Tcf pathway in CR tumorigenesis, we searched for mutations in genes implicated in this pathway in CR tumors lacking APC mutations. No mutations of the gamma-catenin (CTNNG1), GSK-3alpha (GSK3A), or GSK-3beta (GSK3B) genes were detected. In contrast, mutations in the NH2-terminal regulatory domain of beta-catenin (CTNNB1) were found in 13 of 27 (48%) CR tumors lacking APC mutations. Mutations in the beta-catenin regulatory domain and APC were observed to be mutually exclusive, consistent with their equivalent effects on beta-catenin stability and Tcf transactivation. In addition, we found that CTNNB1 mutations can occur in the early, adenomatous stage of CR neoplasia, as has been observed previously with APC mutations. These results suggest that CTNNB1 mutations can uniquely substitute for APC mutations in CR tumors and that beta-catenin signaling plays a critical role in CR tumorigenesis.

    Funded by: NCI NIH HHS: CA57345

    Cancer research 1998;58;6;1130-4

  • Stabilization of beta-catenin by genetic defects in melanoma cell lines.

    Rubinfeld B, Robbins P, El-Gamil M, Albert I, Porfiri E and Polakis P

    Onyx Pharmaceuticals, 3031 Research Drive, Richmond, CA 94806, USA.

    Signal transduction by beta-catenin involves its posttranslational stabilization and downstream coupling to the Lef and Tcf transcription factors. Abnormally high amounts of beta-catenin were detected in 7 of 26 human melanoma cell lines. Unusual messenger RNA splicing and missense mutations in the beta-catenin gene (CTNNB1) that result in stabilization of the protein were identified in six of the lines, and the adenomatous polyposis coli tumor suppressor protein (APC) was altered or missing in two others. In the APC-deficient cells, ectopic expression of wild-type APC eliminated the excess beta-catenin. Cells with stabilized beta-catenin contained a constitutive beta-catenin-Lef-1 complex. Thus, genetic defects that result in up-regulation of beta-catenin may play a role in melanoma progression.

    Funded by: NCI NIH HHS: 1R43CA69931

    Science (New York, N.Y.) 1997;275;5307;1790-2

Pubmed - other

  • Phosphoglycerate kinase 1 a promoting enzyme for peritoneal dissemination in gastric cancer.

    Zieker D, Königsrainer I, Tritschler I, Löffler M, Beckert S, Traub F, Nieselt K, Bühler S, Weller M, Gaedcke J, Taichman RS, Northoff H, Brücher BL and Königsrainer A

    Department of General Visceral, Transplant Surgery Comprehensive Cancer Center, University of Tuebingen, D-72076 Tuebingen, Germany. derek.zieker@med.uni-tuebingen.de

    Peritoneal carcinomatosis is a frequent finding in gastric cancer associated with a poor prognosis. The features that enable gastric tumors to disseminate are poorly understood until now. Previously, we showed elevated mRNA levels of phosphoglycerate kinase 1 (PGK1), an adenosine triphosphate-generating enzyme in the glycolytic pathway, the chemokine receptor 4 (CXCR4), the corresponding chemokine ligand 12 (CXCL12) and beta-catenin in specimens from gastric cancer patients with peritoneal carcinomatosis. In this study, the influence of PGK1 on CXCR4 and beta-catenin was assessed as well as the invasiveness of PGK1 overexpressing cancer cells. In this current study, we found that PGK1 regulates the expression of CXCR4 and beta-catenin at the mRNA and protein levels. On the other hand, CXCR4 regulates the expression of PGK1. Plasmid-mediated overexpression of PGK1 dramatically increased the invasiveness of gastric cancer cells. Interestingly, inhibition of CXCR4 in cells overexpressing PGK1 produced only a moderate reduction of invasiveness suggesting that, PGK1 itself has a critical role in tumor invasiveness. Immunohistochemistry in specimens from diffuse gastric cancer patients also revealed an overexpression of PGK1 in patients with development of peritoneal carcinomatosis. Therefore, PGK1 may be a crucial enzyme in peritoneal dissemination. Together these findings suggest that the enhanced expression of PGK1 and its signaling targets CXCR4 and beta-catenin in gastric cancer cells promote peritoneal carcinomatosis. Thus, PGK1 may serve as prognostic marker and/or be a potential therapeutic target to prevent dissemination of gastric carcinoma cells into the peritoneum.

    Funded by: NCI NIH HHS: CA93900, P01 CA093900, P01 CA093900-06A18687

    International journal of cancer 2010;126;6;1513-20

  • Aberrant changes of Wnt2/beta-catenin signaling pathway induced by sodium nitroprusside in human esophageal squamous cell carcinoma cell lines.

    Wang W, Xue L, Liu H, Wang P, Xu P and Cai Y

    Laboratory for Cell Biology, The First Affiliated Hospital, Zhengzhou University, 40 Daxue Road, Zhengzhou, Henan 450052, China.

    Inhibition of Wnt/beta-catenin pathway is an attractive method for therapy of various tumors including breast, colorectal, and cervical cancer, etc. However, little is known about the role of Wnt2/beta-catenin pathway in esophageal squamous cell carcinoma (ESCC). Here we identify that Wnt2/beta-catenin signaling pathway is activated in ESCC cells, and sodium nitroprusside (SNP) and siRNA against beta-catenin not only inhibit the expressions of beta-catenin and its major downstream effectors including c-myc and cyclin D1, but induce cell cycle arrest and apoptosis, suggesting that Wnt2/beta-catenin pathway may be a potential molecular target for ESCC therapy.

    Cancer investigation 2010;28;3;230-41

  • Low-density lipoprotein receptor-related protein 5 (LRP5) expression in human osteoarthritic chondrocytes.

    Papathanasiou I, Malizos KN and Tsezou A

    University of Thessaly, Medical School, Laboratory of Cytogenetics and Molecular Genetics, Larissa, Greece.

    The aim of this study was to investigate the activation of the Wnt/beta-catenin pathway in osteoarthritis and the role of low-density lipoprotein receptor-related protein 5 (LRP5) in human osteoarthritic chondrocytes. The influence of 1,25(OH)2D3 on the expression of the LRP5 gene in human chondrocytes was also assessed. Human cartilage was obtained from 11 patients with primary osteoarthritis (OA) undergoing total knee replacement surgery. Normal cartilage was obtained from five healthy individuals. Beta-catenin and LRP5 mRNA levels were investigated using real-time PCR and LRP5 protein expression using Western blot analysis. Furthermore, we evaluated the effect of 1,25(OH)2D3 on LRP5 mRNA expression levels in osteoarthritic chondrocytes. Blocking LRP5 expression was performed using small interfering RNA (siRNA) against LRP5, and subsequent MMP-13 mRNA and protein levels were evaluated by real-time PCR and Western blot analysis, respectively. We confirmed the activation of the Wnt/beta-catenin pathway in OA, as we observed significant up-regulation of beta-catenin mRNA expression in osteoarthritic chondrocytes. We also observed that LRP5 mRNA and protein expression were significantly up-regulated in osteoarthritic cartilage compared to normal cartilage, and LRP5 mRNA expression was further increased by vitamin D. Also, blocking LRP5 expression using siRNA against LRP5 resulted in a significant decrease in MMP-13 mRNA and protein expressions. Our findings suggest the catabolic role of LRP5 is mediated by the Wnt/beta-catenin pathway in human osteoarthritis.

    Journal of orthopaedic research : official publication of the Orthopaedic Research Society 2010;28;3;348-53

  • Stretch-induced inhibition of Wnt/beta-catenin signaling in mineralizing osteoblasts.

    Jansen JH, Eijken M, Jahr H, Chiba H, Verhaar JA, van Leeuwen JP and Weinans H

    Department of Orthopaedics, Erasmus University Medical Centre, Room Ee 1614, P.O. Box 2040, 3000 CA Rotterdam, the Netherlands.

    Wnt signaling is important for bone formation and osteoblastic differentiation. Recent findings indicate a stimulating role of Wnt signaling in bone mechanotransduction. However, negative effects of Wnt signaling on osteoblast differentiation and mineralization have been described as well. We conducted in vitro stretch experiments using human pre-osteoblasts to study short- and long-term effects of mechanical loading on Wnt/beta-catenin signaling. As the extracellular regulated kinase (ERK) pathway is known to be involved in mechanotransduction in osteoblasts, we also evaluated its role in Wnt/beta-catenin signaling. Stretch experiments up to 21 days (using stretch episodes of 15 min, alternated with 90 min rest) resulted in higher mineralization compared to static control cultures. We found that 15 min of stretch initially increased nuclear beta-catenin, but ultimately resulted in significant decrease at 12 and 40 h after stretch. Downregulation of Wnt-responsive element activity 16 h after stretch, using a luciferase construct, further supported these findings. The presence of the ERK inhibitor U0126 did not alter the stretch-induced decrease of beta-catenin levels. Our data indicate a biphasic effect of mechanical loading on beta-catenin in mineralizing human differentiating osteoblasts, which is independent of the ERK pathway. The osteogenic potential of our loading regime was confirmed by an increase in osteogenic differentiation markers such as alkaline phosphatase activity and calcium deposition after 3 weeks of culture. We conjecture that the biphasic aspect of Wnt/beta-catenin signaling with a strong decrease up to 40 h after the stretch induction, is important for the anabolic effects of mechanical stretch on bone.

    Journal of orthopaedic research : official publication of the Orthopaedic Research Society 2010;28;3;390-6

  • The low-density lipoprotein receptor-related protein 10 is a negative regulator of the canonical Wnt/beta-catenin signaling pathway.

    Jeong YH, Sekiya M, Hirata M, Ye M, Yamagishi A, Lee SM, Kang MJ, Hosoda A, Fukumura T, Kim DH and Saeki S

    Department of Molecular and Biochemical Nutrition, Graduate School of Human Life Science, Osaka City University, Osaka 558-8585, Japan.

    Wnt signaling pathways play fundamental roles in the differentiation, proliferation and functions of many cells as well as developmental, growth, and homeostatic processes in animals. Low-density lipoprotein receptor (LDLR)-related protein (LRP) 5 and LRP6 serve as coreceptors of Wnt proteins together with Frizzled receptors, triggering activation of canonical Wnt/beta-catenin signaling. Here, we found that LRP10, a new member of the LDLR gene family, inhibits the canonical Wnt/beta-catenin signaling pathway. The beta-catenin/T cell factor (TCF) transcriptional activity in HEK293 cells was activated by transfection with Wnt3a or LRP6, which was then inhibited by co-transfection with LRP10. Deletion of the extracellular domain of LRP10 negated its inhibitory effect. The inhibitory effect of LRP10 was consistently conserved in HEK293 cells even when GSK3beta phosphorylation was inhibited by incubation with lithium chloride and co-transfection with constitutively active S33Y-mutated beta-catenin. Nuclear beta-catenin accumulation was unaffected by LRP10. The present studies suggest that LRP10 may interfere with the formation of the beta-catenin/TCF complex and/or its binding to target DNA in the nucleus, and that the extracellular domain of LRP10 is critical for inhibition of the canonical Wnt/beta-catenin signaling pathway.

    Biochemical and biophysical research communications 2010;392;4;495-9

  • Genetic susceptibility to distinct bladder cancer subphenotypes.

    Guey LT, García-Closas M, Murta-Nascimento C, Lloreta J, Palencia L, Kogevinas M, Rothman N, Vellalta G, Calle ML, Marenne G, Tardón A, Carrato A, García-Closas R, Serra C, Silverman DT, Chanock S, Real FX, Malats N and EPICURO/Spanish Bladder Cancer Study investigators

    Spanish National Cancer Research Centre, Madrid, Spain.

    Background: Clinical, pathologic, and molecular evidence indicate that bladder cancer is heterogeneous with pathologic/molecular features that define distinct subphenotypes with different prognoses. It is conceivable that specific patterns of genetic susceptibility are associated with particular subphenotypes.

    Objective: To examine evidence for the contribution of germline genetic variation to bladder cancer heterogeneity.

    The Spanish Bladder Cancer/EPICURO Study is a case-control study based in 18 hospitals located in five areas in Spain. Cases were patients with a newly diagnosed, histologically confirmed, urothelial cell carcinoma of the bladder from 1998 to 2001. Case diagnoses were reviewed and uniformly classified by pathologists following the World Health Organisation/International Society of Urological Pathology 1999 criteria. Controls were hospital-matched patients (n=1149).

    Measurements: A total of 1526 candidate variants in 423 candidate genes were analysed. Three distinct subphenotypes were defined according to stage and grade: low-grade nonmuscle invasive (n=586), high-grade nonmuscle invasive (n=219), and muscle invasive (n=246). The association between each variant and subphenotype was assessed by polytomous risk models adjusting for potential confounders. Heterogeneity in genetic susceptibility among subphenotypes was also tested.

    Two established bladder cancer susceptibility genotypes, NAT2 slow-acetylation and GSTM1-null, exhibited similar associations among the subphenotypes, as did VEGF-rs25648, which was previously identified in our study. Other variants conferred risks for specific tumour subphenotypes such as PMS2-rs6463524 and CD4-rs3213427 (respective heterogeneity p values of 0.006 and 0.004), which were associated with muscle-invasive tumours (per-allele odds ratios [95% confidence interval] of 0.56 [0.41-0.77] and 0.71 [0.57-0.88], respectively) but not with non-muscle-invasive tumours. Heterogeneity p values were not robust in multiple testing according to their false-discovery rate.

    Conclusions: These exploratory analyses suggest that genetic susceptibility loci might be related to the molecular/pathologic diversity of bladder cancer. Validation through large-scale replication studies and the study of additional genes and single nucleotide polymorphisms are required.

    Funded by: Intramural NIH HHS: ZIA CP010136-16

    European urology 2010;57;2;283-92

  • Hepatitis C virus NS5A protein interacts with beta-catenin and stimulates its transcriptional activity in a phosphoinositide-3 kinase-dependent fashion.

    Milward A, Mankouri J and Harris M

    Institute of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, West Yorkshire, UK.

    Hepatitis C virus (HCV) infection is increasingly associated with the development of hepatocellular carcinoma (HCC). HCV is not thought to be directly oncogenic but, by modulating a range of cellular functions, may predispose patients to the development of liver tumours. However, the molecular mechanisms by which HCV infection might contribute to HCC remain to be characterized. In this regard, we showed previously that the HCV NS5A protein bound to the p85 regulatory subunit of phosphoinositide-3 kinase (PI3K), thereby stimulating the activity of the p110 catalytic subunit of the enzyme. One of the downstream consequences of this was the stabilization of the proto-oncogene, beta-catenin, with a concomitant stimulation of its transcriptional activity. Here, we further analyse the mechanism by which NS5A mediates activation of beta-catenin. Although our previous data were consistent with a role for the PI3K downstream effector kinases, Akt and glycogen synthase kinase-3beta, in NS5A-mediated activation of beta-catenin, we demonstrate here that it is in fact independent of both of these kinases. Truncation analysis revealed that both the N and C termini of NS5A are required for full activation of beta-catenin. Furthermore, we demonstrate that NS5A, either alone or in complex with p85, is able to bind directly to beta-catenin; again both N and C termini contribute to this interaction. We propose that NS5A activates beta-catenin via a novel mechanism that involves a direct interaction between the two proteins and is augmented by PI3K activity. This may contribute to the association between chronic HCV infection and the development of HCC.

    Funded by: Biotechnology and Biological Sciences Research Council: BB/D524875/1; Medical Research Council: G0401577

    The Journal of general virology 2010;91;Pt 2;373-81

  • Flavonoids of Herba Epimedii regulate osteogenesis of human mesenchymal stem cells through BMP and Wnt/beta-catenin signaling pathway.

    Zhang JF, Li G, Chan CY, Meng CL, Lin MC, Chen YC, He ML, Leung PC and Kung HF

    Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, 100084, PR China.

    Herba Epimedii is one of the most commonly used Chinese herbs for treating osteoporosis. In the present study, the flavonoids of Herba Epimedii (HEF) have shown to promote the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. They were noted to enhance the mRNA expression of BMP-2, BMP-4, Runx2, beta-catenin and cyclinD1, all of which are BMP or Wnt-signaling pathway related regulators. The osteogenic effect was inhibited by the introduction of noggin and DKK-1, which is classical inhibitor of BMP and Wnt/beta-catenin signaling, respectively. These results suggest that HEF exerts promoting effect on osteogenic differentiation, which plausibly functions via the BMP and Wnt/beta-catenin signaling pathways. Considering the therapeutic efficiency and economical issues, HEF may be a potential candidate for promoting bone regeneration. On the other hand, osteogenic differentiation of MSCs may also be a promising and attractive tool to apply in bone repair.

    Molecular and cellular endocrinology 2010;314;1;70-4

  • Identification of beta-catenin as a target of the intracellular tyrosine kinase PTK6.

    Palka-Hamblin HL, Gierut JJ, Bie W, Brauer PM, Zheng Y, Asara JM and Tyner AL

    Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.

    Disruption of the gene encoding protein tyrosine kinase 6 (PTK6) leads to increased growth, impaired enterocyte differentiation and higher levels of nuclear beta-catenin in the mouse small intestine. Here, we demonstrate that PTK6 associates with nuclear and cytoplasmic beta-catenin and inhibits beta-catenin- and T-cell factor (TCF)-mediated transcription. PTK6 directly phosphorylates beta-catenin on Tyr64, Tyr142, Tyr331 and/or Tyr333, with the predominant site being Tyr64. However, mutation of these sites does not abrogate the ability of PTK6 to inhibit beta-catenin transcriptional activity. Outcomes of PTK6-mediated regulation appear to be dependent on its intracellular localization. In the SW620 colorectal adenocarcinoma cell line, nuclear-targeted PTK6 negatively regulates endogenous beta-catenin/TCF transcriptional activity, whereas membrane-targeted PTK6 enhances beta-catenin/TCF regulated transcription. Levels of TCF4 and the transcriptional co-repressor TLE/Groucho increase in SW620 cells expressing nuclear-targeted PTK6. Knockdown of PTK6 in SW620 cells leads to increased beta-catenin/TCF transcriptional activity and increased expression of beta-catenin/TCF target genes Myc and Survivin. Ptk6-null BAT-GAL mice, containing a beta-catenin-activated LacZ reporter transgene, have increased levels of beta-galactosidase expression in the gastrointestinal tract. The ability of PTK6 to negatively regulate beta-catenin/TCF transcription by modulating levels of TCF4 and TLE/Groucho could contribute to its growth-inhibitory activities in vivo.

    Funded by: NIDDK NIH HHS: DK068503, DK44525, R01 DK044525, R01 DK044525-15, R01 DK068503, R01 DK068503-05, T32 DK007739, T32 DK07739

    Journal of cell science 2010;123;Pt 2;236-45

  • Downregulation of E-cadherin is an essential event in activating beta-catenin/Tcf-dependent transcription and expression of its target genes in Pdcd4 knockdown cells.

    Wang Q, Sun ZX, Allgayer H and Yang HS

    Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA.

    We reported earlier that knockdown of tumor suppressor Pdcd4 (programed cell death 4) downregulates E-cadherin expression and activates beta-catenin/Tcf (T-cell factor)-dependent transcription in colon tumor cells. However, the underlying mechanism of these observations remains unknown. In this study, we showed that knockdown of Pdcd4 downregulates E-cadherin expression through elevated protein level of Snail. Over-expression of Pdcd4 upregulates E-cadherin expression and inhibits beta-catenin/Tcf-dependent transcription. We then showed that knockdown of E-cadherin activates beta-catenin/Tcf-dependent transcription. Conversely, over-expression of E-cadherin in Pdcd4 knockdown cells inhibits beta-catenin/Tcf-dependent transcription. In addition, Pdcd4 knockdown stimulates urokinase-type plasminogen activator receptor (u-PAR) and c-Myc expression, whereas u-PAR and c-Myc expression can be reversed by over-expressing E-cadherin in Pdcd4 knockdown cells. Using chromatin immunoprecipitation, we showed that beta-catenin/Tcf4 directly binds to the promoters of u-PAR and c-myc in Pdcd4 knockdown cells. Futhermore, knockdown of u-PAR or c-Myc inhibits invasion in Pdcd4 knockdown cells, suggesting that both u-PAR and c-Myc contribute to invasion induced by Pdcd4 knockdown. Taken together, our data showed that elevated Snail expression by Pdcd4 knockdown leads to downregulation of E-cadherin resulting in activating beta-catenin/Tcf-dependent transcription and stimulating the expression of c-Myc and u-PAR, thus providing molecular explanation of how Pdcd4 suppresses tumor invasion.

    Funded by: NCI NIH HHS: R01 CA129015, R01 CA129015-01A2, R01CA129015; NCRR NIH HHS: P20 RR020171, P20 RR020171-05, P20RR020171

    Oncogene 2010;29;1;128-38

  • A beta-catenin/TCF-coordinated chromatin loop at MYC integrates 5' and 3' Wnt responsive enhancers.

    Yochum GS, Sherrick CM, Macpartlin M and Goodman RH

    Vollum Institute and Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, OR 97239, USA. gsy3@psu.edu

    Aberrant MYC gene expression by the Wnt/beta-catenin pathway is implicated in colorectal carcinogenesis. Wnt/beta-catenin signaling stimulates association of the beta-catenin coactivator complex with two Wnt responsive enhancers (WREs) located in close proximity to MYC gene boundaries. Each enhancer directly binds members of the TCF/Lef family of transcription factors that, in turn, recruit beta-catenin. In a previous report, we showed that the downstream MYC enhancer (MYC 3' WRE) cooperated with the upstream enhancer (MYC 5' WRE) to activate expression of a heterologous reporter gene in response to Wnt/beta-catenin and mitogen signaling. Here we use chromatin conformation capture (3C) to show that the MYC 5' and 3' WREs are juxtaposed at the genomic MYC locus during active transcription. This MYC 5'3' chromatin loop is present in HCT116 human colorectal cancer cells that contain high levels of nuclear beta-catenin and is absent in HEK293 cells that contain trace amounts of nuclear beta-catenin. Depletion of functional beta-catenin/TCF complexes blocks formation of the MYC 5'3 chromatin loop. Furthermore, we find that the chromatin loop is absent in quiescent cells, but is rapidly and transiently induced by serum mitogens in a beta-catenin-dependent manner. Thus, we propose that a distinct chromatin architecture coordinated by beta-catenin/TCF-bound WREs accompanies transcriptional activation of MYC gene expression.

    Funded by: NIDDK NIH HHS: R01 DK080805, R01 DK080805-03

    Proceedings of the National Academy of Sciences of the United States of America 2010;107;1;145-50

  • MicroRNA-145 suppresses cell invasion and metastasis by directly targeting mucin 1.

    Sachdeva M and Mo YY

    Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, Illinois 62794, USA.

    MicroRNAs are important gene regulators that could play a profound role in tumorigenesis. Our previous studies indicate that miR-145 is a tumor suppressor capable of inhibiting tumor cell growth both in vitro and in vivo. In this study, we show that miR-145 exerts its function in a cell-specific manner. Although miR-145 inhibits cell growth in MCF-7 and HCT-116 cells, it has no significant effect on cell growth in metastatic breast cancer cell lines. However, miR-145 significantly suppresses cell invasion in these cells; in contrast, the antisense oligo against miR-145 increases cell invasion. miR-145 is also able to suppress lung metastasis in an experimental metastasis animal model. This miR-145-mediated suppression of cell invasion is in part due to the silencing of the metastasis gene mucin 1 (MUC1). Using luciferase reporters carrying the 3'-untranslated region of MUC1 combined with Western blot and immunofluorescence staining, we identify MUC1 as a direct target of miR-145. Moreover, ectopic expression of MUC1 enhances cell invasion, which can be blocked by miR-145. Of interest, suppression of MUC1 by miR-145 causes a reduction of beta-catenin as well as the oncogenic cadherin 11. Finally, suppression of MUC1 by RNAi mimics the miR-145 action in suppression of invasion, which is associated with downregulation of beta-catenin and cadherin 11. Taken together, these results suggest that as a tumor suppressor, miR-145 inhibits not only tumor growth but also cell invasion and metastasis.

    Funded by: NCI NIH HHS: CA102630, R01 CA102630, R01 CA102630-05, R01 CA154989

    Cancer research 2010;70;1;378-87

  • miR-200a-mediated downregulation of ZEB2 and CTNNB1 differentially inhibits nasopharyngeal carcinoma cell growth, migration and invasion.

    Xia H, Ng SS, Jiang S, Cheung WK, Sze J, Bian XW, Kung HF and Lin MC

    Integrative Chemical Biology Laboratory, Institute of Molecular Technology, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China.

    Nasopharyngeal carcinoma (NPC), a highly metastatic and invasive malignant tumor originating from the nasopharynx, is widely prevalent in Southeast Asia, the Middle East and North Africa. Although viral, dietary and genetic factors have been implicated in NPC, the molecular basis of its pathogenesis is not well defined. Based on a recent microRNA (miRNA) microarray study showing miR-200 downregulation in NPC, we further investigated the role of miR-200a in NPC carcinogenesis. We found that the endogenous miR-200a expression level increases with the degree of differentiation in a panel of NPC cell lines, namely undifferentiated C666-1, high-differentiated CNE-1, and low-differentiated CNE-2 and HNE1 cells. By a series of gain-of-function and loss-of-function studies, we showed that over-expression of miR-200a inhibits C666-1 cell growth, migration and invasion, whereas its knock-down stimulates these processes in CNE-1 cells. In addition, we further identified ZEB2 and CTNNB1 as the functional downstream targets of miR-200a. Interestingly, knock-down of ZEB2 solely impeded NPC cell migration and invasion, whereas CTNNB1 suppression only inhibited NPC cell growth, suggesting that the inhibitory effects of miR-200a on NPC cell growth, migration and invasion are mediated by distinct targets and pathways. Our results reveal the important role of miR-200a as a regulatory factor of NPC carcinogenesis and a potential candidate for miRNA-based therapy against NPC.

    Biochemical and biophysical research communications 2010;391;1;535-41

  • Osteopontin induces beta-catenin signaling through activation of Akt in prostate cancer cells.

    Robertson BW and Chellaiah MA

    Department of Oncology and Diagnostic Sciences, Dental School, University of Maryland, Baltimore, MD 21201, USA.

    Secretion of osteopontin (OPN) by cancer cells is a known mediator of tumorigenesis and cancer progression in both experimental and clinical studies. Our work demonstrates that OPN can activate Akt, an important step in cancer progression. Both ILK and PI3K are integral proteins in the OPN/Akt pathway, as inhibition of either kinase leads to a loss of OPN-mediated Akt activation. Subsequent to OPN-induced Akt activation, we observe inactivation of GSK-3beta, a regulator of beta-catenin. Osteopontin stimulation leads to an overall increase in beta-catenin protein levels with a resultant transfer of beta-catenin to the nucleus. Through the nuclear import of beta-catenin, OPN increases both the transcription and protein levels of MMP-7 and CD44, which are known TCF/LEF transcription targets. This work describes an important aspect of cancer progression induced by OPN.

    Funded by: NIAMS NIH HHS: AR46292, R01 AR046292, R56 AR046292, R56 AR046292-09A1; NIDCR NIH HHS: F30 DE018308, F30 DE18308, T32 DE007309, T32 DE07309

    Experimental cell research 2010;316;1;1-11

  • Small-molecule inhibitors of phosphatidylinositol 3-kinase/Akt signaling inhibit Wnt/beta-catenin pathway cross-talk and suppress medulloblastoma growth.

    Baryawno N, Sveinbjörnsson B, Eksborg S, Chen CS, Kogner P and Johnsen JI

    Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden. ninib.baryawno@ki.se

    Activation of the beta-catenin and receptor kinase pathways occurs often in medulloblastoma, the most common pediatric malignant brain tumor. In this study, we show that molecular cross-talk between the beta-catenin and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways is crucial to sustain medulloblastoma pathophysiology. Constitutive activation of phosphoinositide-dependent protein kinase 1 (PDK1), Akt, and phosphorylation of [corrected] glycogen synthase kinase 3beta (GSK-3beta) was detected by immunohistochemistry in all primary medulloblastomas examined (n = 41). Small-molecule inhibitors targeting the PI3K/Akt signaling pathway affected beta-catenin signaling by activation [corrected] of GSK-3beta, [corrected] resulting in cytoplasmic retention of beta-catenin and reduced expression of its target genes cyclin D1 and c-Myc. The PDK1 inhibitor OSU03012 induced mitochondrial-dependent apoptosis of medulloblastoma cells and enhanced the cytotoxic effects of chemotherapeutic drugs in a synergistic or additive manner. In vivo, OSU03012 inhibited the growth of established medulloblastoma xenograft tumors in a dose-dependent manner and augmented the antitumor effects of mammalian target of rapamycin inhibitor CCI-779. These findings demonstrate the importance of cross-talk between the PI3K/Akt and beta-catenin pathways in medulloblastoma and rationalize the PI3K/Akt signaling pathway as a therapeutic target in treatment of this disease.

    Cancer research 2010;70;1;266-76

  • Association analysis of Wnt pathway genes on prostate-specific antigen recurrence after radical prostatectomy.

    Huang SP, Ting WC, Chen LM, Huang LC, Liu CC, Chen CW, Hsieh CJ, Yang WH, Chang TY, Lee HZ and Bao BY

    Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.

    Background: Approximately one-third of prostate cancer (PCa) patients show biochemical failure after radical prostatectomy (RP) and are prone to develop metastasis with significant mortality. Although aberrant Wnt/beta-catenin (CTNNB1) signaling has been observed in numerous types of human cancers, including PCa, to our knowledge there is currently no information on the role of Wnt signaling gene polymorphisms in PCa.

    Methods: We comprehensively studied the contribution of genetic variations in CTNNB1 and adenomatous polyposis coli (APC), one of the key genes encoding the CTNNB1 destruction complex, to PCa risk and prognosis after RP using a hospital-based case-control study. We selected and genotyped 13 tagged single-nucleotide polymorphisms (tSNP) to predict common variants across entire APC and CTNNB1 genes in 307 patients with clinically localized PCa who received RP and 371 unaffected controls.

    Results: Four tSNPs (rs3846716, rs2431238, rs41115, and rs565453) and a specific haplotype (GTAAGA) in the APC tumor suppressor gene were associated with a 0.57- to 0.71-fold lower risk of localized PCa. The association of tSNPs with prostate-specific antigen (PSA) recurrence in PCa patients was then analyzed by Kaplan-Meier analysis and Cox regression model. Interestingly, we found that the APC rs3846716 GA/AA genotypes were also significantly associated with poorer PSA-free survival (log-rank test, P = 0.037) compared with the GG genotype.

    Conclusions: This is the first report documenting the potential prognostic role of the APC rs3846716 GA/AA genotype on PSA recurrence after RP.

    Annals of surgical oncology 2010;17;1;312-22

  • Cytoplasmic localization of beta-catenin is a marker of poor outcome in breast cancer patients.

    López-Knowles E, Zardawi SJ, McNeil CM, Millar EK, Crea P, Musgrove EA, Sutherland RL and O'Toole SA

    Cancer Research Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.

    Beta-catenin is involved in cell adhesion through catenin-cadherin complexes and as a transcriptional regulator in the Wnt signaling pathway. Its deregulation is important in the genesis of a number of human malignancies, particularly colorectal cancer. A range of studies has been undertaken in breast cancer, with contradictory associations reported among beta-catenin expression, clinicopathologic variables, and disease outcome. We undertook an immunohistochemical study measuring the levels and subcellular localization of beta-catenin in 292 invasive ductal breast cancers with known treatment and outcome. No association with breast cancer-specific death was observed for cytoplasmic or membrane expression alone; however, a continuous score representing both locations (membrane minus cytoplasmic expression: MTC score) was associated with a worse outcome in univariate analysis (P = 0.004), and approached significance in a multivariate analysis model that included lymph node, progesterone receptor (PR), and HER2 status (P = 0.054). Therefore, the MTC score was used for further statistical analyses due to the importance of both the subcellular location and the levels of expression of beta-catenin. An association was identified between high cytoplasmic expression (low MTC score), and high tumor grade (P = 0.004), positive Ki67 (P = 0.005), negative estrogen receptor (ER) (P = 0.005), positive HER2 (P = 0.04) status, and an active phosphoinositide 3-kinase pathway (P = 0.005), measured as PIK3CA mutations (P = 0.05) or PTEN loss (P = 0.05). Low cytoplasmic expression (high MTC score) was associated with the luminal A subtype (P = 0.004). In conclusion, a low beta-catenin MTC score is associated with an adverse outcome in breast cancer, which may be of mechanistic significance in the disease process.

    Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology 2010;19;1;301-9

  • Low membranous expression of beta-catenin and high mitotic count predict poor prognosis in endometrioid carcinoma of the ovary.

    Rosen DG, Zhang Z, Chang B, Wang X, Lin E and Liu J

    Department of Pathology, Baylor College of Medicine, Houston, TX, USA.

    Mutations in the beta-catenin gene are common in ovarian endometrioid carcinoma. Few studies have addressed the association of beta-catenin expression with tumor characteristics and patient outcome, yielding controversial results. The purpose of this study was to retrospectively assess the expression of beta-catenin in ovarian endometrioid carcinoma and correlate its expression with the Gynecologic Oncology Group's (GOG) grading system, clinicopathological characteristics, and patient survival. A total of 49 patients with primary ovarian endometrioid carcinoma were included in this study. A four-tier score grading system was used for the membranous staining (negative, weak, moderate, and strong) and the percentage of positive cells for the nuclear staining of beta-catenin. The status of five morphometric parameters, nuclear morphology (uniform or pleomorphic), mitotic count, glandular pattern, degree of squamous differentiation, and status of papillary pattern, was assessed. We found that a low membranous expression of beta-catenin and a high mitotic count (>15 per 10 high-power fields) were significantly associated with poor prognosis and early recurrence of ovarian endometrioid carcinoma. In addition, cases with nuclear expression of beta-catenin showed an intermediate overall survival risk and late disease recurrence. Young age at the time of diagnosis, advanced disease stage, and suboptimal debulking were among the clinical factors predicting poor survival and early disease recurrence. The presence of squamous differentiation, a papillary pattern or nuclear pleomorphism did not show any correlation with overall survival or disease-free survival. Low membranous expression of beta-catenin and high mitotic count are poor prognostic indicators in patients with ovarian endometrioid carcinoma, whereas the GOG grading system showed no prognostic value. Our data suggest that there is a need to define a better grading system for ovarian endometrioid carcinoma. Molecular markers such as beta-catenin and mitotic count could aid in defining this grading system.

    Funded by: NCI NIH HHS: CA016672, IP50CA83638, R01 CA131183

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2010;23;1;113-22

  • Nuclear beta-catenin induces an early liver progenitor phenotype in hepatocellular carcinoma and promotes tumor recurrence.

    Zulehner G, Mikula M, Schneller D, van Zijl F, Huber H, Sieghart W, Grasl-Kraupp B, Waldhör T, Peck-Radosavljevic M, Beug H and Mikulits W

    Department of Internal Medicine I, Centre of Public Health, Medical University of Vienna, Vienna, Austria.

    Transforming growth factor-beta cooperates with oncogenic Ras to activate nuclear beta-catenin during the epithelial to mesenchymal transition of hepatocytes, a process relevant in the progression of hepatocellular carcinoma (HCC). In this study we investigated the role of beta-catenin in the differentiation of murine, oncogene-targeted hepatocytes and in 133 human HCC patients scheduled for orthotopic liver transplantation. Transforming growth factor-beta caused dissociation of plasma membrane E-cadherin/beta-catenin complexes and accumulation of nuclear beta-catenin in Ras-transformed, but otherwise normal hepatocytes in p19(ARF)-/- mice. Both processes were inhibited by Smad7-mediated disruption of transforming growth factor-beta signaling. Overexpression of constitutively active beta-catenin resulted in high levels of CK19 and M2-PK, whereas ablation of beta-catenin by axin overexpression caused strong expression of CK8 and CK18. Therefore, nuclear beta-catenin resulted in dedifferentiation of neoplastic hepatocytes to immature progenitor cells, whereas loss of nuclear beta-catenin led to a differentiated HCC phenotype. Poorly differentiated human HCC showed cytoplasmic redistribution or even loss of E-cadherin, suggesting epithelial to mesenchymal transition. Analysis of 133 HCC patient samples revealed that 58.6% of human HCC exhibited strong nuclear beta-catenin accumulation, which correlated with clinical features such as vascular invasion and recurrence of disease after orthotopic liver transplantation. These data suggest that activation of beta-catenin signaling causes dedifferentiation to malignant, immature hepatocyte progenitors and facilitates recurrence of human HCC after orthotopic liver transplantation.

    Funded by: Austrian Science Fund FWF: F 2801, F 2802, F 2806, P 19598

    The American journal of pathology 2010;176;1;472-81

  • Analysis of association of LRP5, LRP6, SOST, DKK1, and CTNNB1 genes with bone mineral density in a Slovenian population.

    Mencej-Bedrac S, Prezelj J, Kocjan T, Komadina R and Marc J

    Faculty of Pharmacy, Department of Clinical Biochemistry, University of Ljubljana, Askerceva cesta 7, 1000, Ljubljana, Slovenia.

    The Wnt pathway has a bifunctional role in bone mass regulation, influencing osteoblasts and osteoclasts. The Wnt pathway genes are therefore candidate genes for susceptibility to osteoporosis. In our study, we focused on the effects of polymorphisms in selected Wnt pathway genes: low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and LRP6), Dickkopf1 (DKK1), sclerostin (SOST), and beta-catenin (CTNNB1). We genotyped 652 subjects for the following polymorphisms: A1330V in LRP5; I1062V in LRP6; E232K in DKK1; D32Y, G34V, and N287S in CTNNB1; and -1397_-1396insGGA in SOST. Bone mineral density (BMD) was also measured. The allele frequencies were as follows: for A1330V C:T = 87%:13%, for I1062V C:T = 20%:80%, and for -1397_-1396insGGA-:GGA = 64%:36%. The studied nucleotide changes in the DKK1 and CTNNB1 genes were shown not to be polymorphic. In a Slovenian population, no association was shown between lumbar spine and femoral neck BMD in A1330V (P = 0.151 and 0.243) and in I1062V (P = 0.209 and 0.405). We observed a difference between SOST genotypes, corresponding to an allele dose effect, which was borderline significant for lumbar spine and femoral neck BMD (P = 0.047 and 0.085); but this did not survive the adjustment for multiple testing. These results indicate that a larger sample size would be necessary to detect these subtle effects. Our results suggest that A1330V in LRP5, I1062V in LRP6, and -1397_-1396insGGA in SOST are not associated with BMD in the Slovenian population.

    Calcified tissue international 2009;85;6;501-6

  • Beta-catenin nuclear labeling is a common feature of sessile serrated adenomas and correlates with early neoplastic progression after BRAF activation.

    Yachida S, Mudali S, Martin SA, Montgomery EA and Iacobuzio-Donahue CA

    Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.

    Recent observations indicate that some sessile serrated adenomas (SSAs) have aberrant beta-catenin nuclear labeling, implicating the Wnt pathway in the molecular progression of SSAs to colorectal carcinoma. We sought to expand upon this finding by characterizing beta-catenin expression in the full spectrum of serrated colorectal polyps, and correlating these findings with the genetic status of BRAF, KRAS and CTNNB1. Immunolabeling for beta-catenin confirmed the presence of abnormal nuclear accumulation in SSAs, with 35/54 (67%) SSAs showing nuclear labeling compared with 0/12 hyperplastic polyps. Abnormal nuclear labeling was also identified in 4/11 (36%) traditional serrated adenomas (TSAs) (P=0.00001). When SSAs were further analyzed with respect to the presence or absence of conventional epithelial dysplasia, nuclear beta-catenin labeling was seen in 8/27 (29%) SSAs without dysplasia (SSA) but in 27/27 (100%) of SSAs with dysplasia (P=0.000001). Sequencing of genomic DNA extracted from a subset of hyperplastic polyps, SSAs, SSAs with dysplasia, TSAs and tubular adenomas failed to identify any CTNNB1 mutations to account for abnormal beta-catenin nuclear labeling. However, abnormal nuclear labeling always occurred in the setting of a BRAF V600E mutation, indicating aberrant nuclear labeling occurs on a background of BRAF activation. Of interest, all 6 TSAs contained a KRAS mutation confirming that SSAs and TSAs are genetically distinct entities. These findings validate previous reports implicating activation of the Wnt signaling pathway in SSAs, and further indicate that Wnt pathway activation plays a role in the neoplastic progression of SSAs and TSAs to colonic carcinoma by mechanisms independent of CTNNB1 mutation.

    Funded by: NCI NIH HHS: CA106610, K08 CA106610, K08 CA106610-05

    The American journal of surgical pathology 2009;33;12;1823-32

  • High-density association study of 383 candidate genes for volumetric BMD at the femoral neck and lumbar spine among older men.

    Yerges LM, Klei L, Cauley JA, Roeder K, Kammerer CM, Moffett SP, Ensrud KE, Nestlerode CS, Marshall LM, Hoffman AR, Lewis C, Lang TF, Barrett-Connor E, Ferrell RE, Orwoll ES, Zmuda JM and MrOS Research Group

    Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.

    Genetics is a well-established but poorly understood determinant of BMD. Whereas some genetic variants may influence BMD throughout the body, others may be skeletal site specific. We initially screened for associations between 4608 tagging and potentially functional single nucleotide polymorphisms (SNPs) in 383 candidate genes and femoral neck and lumbar spine volumetric BMD (vBMD) measured from QCT scans among 862 community-dwelling white men >or=65 yr of age in the Osteoporotic Fractures in Men Study (MrOS). The most promising SNP associations (p < 0.01) were validated by genotyping an additional 1156 white men from MrOS. This analysis identified 8 SNPs in 6 genes (APC, DMP1, FGFR2, FLT1, HOXA, and PTN) that were associated with femoral neck vBMD and 13 SNPs in 7 genes (APC, BMPR1B, FOXC2, HOXA, IGFBP2, NFATC1, and SOST) that were associated with lumbar spine vBMD in both genotyping samples (p < 0.05). Although most associations were specific to one skeletal site, SNPs in the APC and HOXA gene regions were associated with both femoral neck and lumbar spine BMD. This analysis identifies several novel and robust genetic associations for volumetric BMD, and these findings in combination with other data suggest the presence of genetic loci for volumetric BMD that are at least to some extent skeletal-site specific.

    Funded by: NCRR NIH HHS: UL1 RR024140, UL1 RR024153; NIA NIH HHS: T32 AG000181, T32-AG00181, U01 AG018197, U01 AG027810, U01 AG042140, U01 AG18197, U01-AG027810; NIAMS NIH HHS: R01 AR051124, R01-AR051124, U01 AR045580, U01 AR045583, U01 AR045614, U01 AR045632, U01 AR045647, U01 AR045654, U01 AR45580, U01 AR45583, U01 AR45614, U01 AR45632, U01 AR45647, U01 AR45654

    Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 2009;24;12;2039-49

  • Immunohistochemical analyses of E-cadherin, beta-catenin, CD44s, and CD44v6 expressions, and Ki-67 labeling index in intraductal papillary mucinous neoplasms of the pancreas and associated invasive carcinomas.

    Okimura A, Hirano H, Nishigami T, Ueyama S, Tachibana S, Fukuda Y, Yamanegi K, Ohyama H, Terada N and Nakasho K

    Department of Pathology, Hyogo College of Medicine, Hyogo, Japan.

    We examined the expressions of adhesion molecules (E-cadherin, beta-catenin, CD44s, and CD44v6) and Ki-67 labeling index (Ki-67 LI) in low- and moderate-grade dysplasia and invasive carcinoma components in ten noninvasive intraductal papillary mucinous neoplasms (IPMNs) of the pancreas and eight invasive carcinomas associated with IPMNs of the pancreas using immunohistochemical methods. There was no significant difference in regard to the proportion of components expressing either E-cadherin or beta-catenin in more than 70% of the tumor cells between the low- and moderate-grade dysplasia components. In contrast, the proportion of those in invasive carcinoma components was significantly lower than in low- or moderate-grade dysplasia components. Also, there was no significant difference in the proportion of components expressing CD44s or CD44v6 in more than 5% of tumor cells among low-grade dysplasia, moderate-grade dysplasia, and invasive carcinoma components. In contrast, the Ki-67 LI values increased in the order of low-grade dysplasia, moderate-grade dysplasia, and invasive carcinoma components, with significant differences among them. The present results indicate that carcinoma components are associated with a decrease in tumor cells expressing E-cadherin and beta-catenin and have the highest proliferative activity.

    Medical molecular morphology 2009;42;4;222-9

  • PTEN identified as important risk factor of chronic obstructive pulmonary disease.

    Hosgood HD, Menashe I, He X, Chanock S and Lan Q

    Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.

    Common genetic variation may play an important role in altering chronic obstructive pulmonary disease (COPD) risk. In Xuanwei, China, the COPD rate is more than twice the Chinese national average, and COPD is strongly associated with in-home coal use. To identify genetic variation that may be associated with COPD in a population with substantial in-home coal smoke exposures, we evaluated 1261 single nucleotide polymorphisms (SNPs) in 380 candidate genes potentially relevant for cancer and other human diseases in a population-based case-control study in Xuanwei (53 cases; 107 controls). PTEN was the most significantly associated gene with COPD in a minP analysis using 20,000 permutations (P=0.00005). SNP-based analyses found that homozygote variant carriers of PTEN rs701848 (OR(TT)=0.12, 95% CI=0.03-0.47) had a significant decreased risk of COPD. PTEN, or phosphatase and tensin homolog, is an important regulator of cell cycle progression and cellular survival via the AKT signaling pathway. Our exploratory analysis suggests that genetic variation in PTEN may be an important risk factor of COPD in Xuanwei. However, due to the small sample size, additional studies are needed to evaluate these associations within Xuanwei and other populations with coal smoke exposures.

    Funded by: Intramural NIH HHS: Z99 CA999999

    Respiratory medicine 2009;103;12;1866-70

  • Solid-pseudopapillary neoplasm: a pancreatic enigma.

    Chakhachiro ZI and Zaatari G

    Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon. z_shak@hotmail.com

    Solid-pseudopapillary neoplasm of the pancreas is a relatively uncommon tumor. It typically affects young women, has nonspecific clinical and radiologic manifestations, and can be readily diagnosed by ultrasound-guided fine-needle aspiration and histopathologic evaluation. Histologic features characteristically show loosely cohesive, relatively uniform polygonal cells surrounding delicate capillary-sized blood vessels. Other features include cytoplasmic vacuolization, finely stippled chromatin, nuclear grooving, eosinophilic hyaline globules, and degenerative changes. Almost all solid-pseudopapillary neoplasms harbor mutations in the beta-catenin gene. They stain with beta-catenin, CD10, and focally with neuroendocrine markers. Although previously considered benign, this tumor is currently considered a low-grade malignant epithelial neoplasm with low metastatic rate and high overall survival. Most patients are cured by complete surgical excision. Despite the characterization of the morphologic and molecular features of this enigmatic neoplasm, more work is needed to uncover its cell of origin and true histogenesis.

    Archives of pathology & laboratory medicine 2009;133;12;1989-93

  • Transcriptional mechanisms by the coregulator MAML1.

    Saint Just Ribeiro M and Wallberg AE

    Department of Biosciences and Nutrition, Karolinska Institutet, 141 86 Stockholm, Sweden.

    The Mastermind-like (MAML) proteins are transcriptional coactivators for Notch signaling, an evolutionarily conserved pathway that plays several key roles in development and in human disease. The MAML family contains MAML1, MAML2, and MAML3. More recently, MAML1 has been shown to function as a coactivator for the tumor suppressor p53, the MADS box transcription enhancer factor (MEF) 2C, and beta-catenin. In addition, MAML1 has been reported to interact with the histone acetyltransferase p300, and this interaction increases p300 activity. Furthermore, MAML1 binds to CDK8, which is a subunit of the Mediator complex. The function of MAML1 as a coactivator for diverse activators, and MAML1 interaction with broadly used coactivators, suggests that MAML1 might be a key molecule that connects various signaling pathways to regulate cellular processes in normal cells and in human disease.

    Current protein & peptide science 2009;10;6;570-6

  • EGF-induced ERK activation promotes CK2-mediated disassociation of alpha-Catenin from beta-Catenin and transactivation of beta-Catenin.

    Ji H, Wang J, Nika H, Hawke D, Keezer S, Ge Q, Fang B, Fang X, Fang D, Litchfield DW, Aldape K and Lu Z

    Brain Tumor Center and Department of Neuro-Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, 77030, USA.

    Increased transcriptional activity of beta-catenin resulting from Wnt/Wingless-dependent or -independent signaling has been detected in many types of human cancer, but the underlying mechanism of Wnt-independent regulation remains unclear. We demonstrate here that EGFR activation results in disruption of the complex of beta-catenin and alpha-catenin, thereby abrogating the inhibitory effect of alpha-catenin on beta-catenin transactivation via CK2alpha-dependent phosphorylation of alpha-catenin at S641. ERK2, which is activated by EGFR signaling, directly binds to CK2alpha via the ERK2 docking groove and phosphorylates CK2alpha primarily at T360/S362, subsequently enhancing CK2alpha activity toward alpha-catenin phosphorylation. In addition, levels of alpha-catenin S641 phosphorylation correlate with levels of ERK1/2 activity in human glioblastoma specimens and with grades of glioma malignancy. This EGFR-ERK-CK2-mediated phosphorylation of alpha-catenin promotes beta-catenin transactivation and tumor cell invasion. These findings highlight the importance of the crosstalk between EGFR and Wnt pathways in tumor development.

    Funded by: NCI NIH HHS: 5R01CA109035, R01 CA109035, R01 CA109035-05

    Molecular cell 2009;36;4;547-59

  • Wnt signaling stimulates transcriptional outcome of the Hedgehog pathway by stabilizing GLI1 mRNA.

    Noubissi FK, Goswami S, Sanek NA, Kawakami K, Minamoto T, Moser A, Grinblat Y and Spiegelman VS

    Department of Dermatology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA.

    Wnt and Hedgehog signaling pathways play central roles in embryogenesis, stem cell maintenance, and tumorigenesis. However, the mechanisms by which these two pathways interact are not well understood. Here, we identified a novel mechanism by which Wnt signaling pathway stimulates the transcriptional output of Hedgehog signaling. Wnt/beta-catenin signaling induces expression of an RNA-binding protein, CRD-BP, which in turn binds and stabilizes GLI1 mRNA, causing an elevation of GLI1 expression and transcriptional activity. The newly described mode of regulation of GLI1 seems to be important to several functions of Wnt, including survival and proliferation of colorectal cancer cells.

    Funded by: NCI NIH HHS: R01 CA121851, R01 CA121851-01A1, R01 CA121851-02, R01 CA121851-03; NIGMS NIH HHS: R01 GM076244

    Cancer research 2009;69;22;8572-8

  • Beta-catenin is involved in alterations in mitochondrial activity in non-transformed intestinal epithelial and colon cancer cells.

    Mezhybovska M, Yudina Y, Abhyankar A and Sjölander A

    Cell and Experimental Pathology, Department of Laboratory Medicine, Malmö University Hospital, Lund University, Malmö, SE-205 02, Sweden.

    Background: Alteration in respiratory activity and mitochondrial DNA (mtDNA) transcription seems to be an important feature of cancer cells. Leukotriene D(4) (LTD(4)) is a proinflammatory mediator implicated in the pathology of chronic inflammation and cancer. We have shown earlier that LTD(4) causes translocation of beta-catenin both to the mitochondria, in which it associates with the survival protein Bcl-2 identifying a novel role for beta-catenin in cell survival, and to the nucleus in which it activates the TCF/LEF transcription machinery.

    Methods: Here we have used non-transformed intestinal epithelial Int 407 cells and Caco-2 colon cancer cells, transfected or not with wild type and mutated (S33Y) beta-catenin to analyse its effect on mitochondria activity. We have measured the ATP/ADP ratio, and transcription of the mtDNA genes ND2, ND6 and 16 s in these cells stimulated or not with LTD(4).

    Results: We have shown for the first time that LTD(4) triggers a cellular increase in NADPH dehydrogenase activity and ATP/ADP ratio. In addition, LTD(4) significantly increased the transcription of mtDNA genes. Overexpression of wild-type beta-catenin or a constitutively active beta-catenin mutant mimicked the effect of LTD(4) on ATP/ADP ratio and mtDNA transcription. These elevations in mitochondrial activity resulted in increased reactive oxygen species levels and subsequent activations of the p65 subunit of NF-kappaB.

    Conclusions: The present novel data show that LTD(4), presumably through beta-catenin accumulation in the mitochondria, affects mitochondrial activity, lending further credence to the idea that inflammatory signalling pathways are intrinsically linked with potential oncogenic signals.

    British journal of cancer 2009;101;9;1596-605

  • Phosphorylation of PPP(S/T)P motif of the free LRP6 intracellular domain is not required to activate the Wnt/beta-catenin pathway and attenuate GSK3beta activity.

    Beagle B, Mi K and Johnson GV

    Department of Anesthesiology, University of Rochester, Rochester, New York 14642, USA.

    The canonical Wnt/beta-catenin signaling pathway plays a critical role in numerous physiological and pathological processes. LRP6 is an essential co-receptor for Wnt/beta-catenin signaling; as transduction of the Wnt signal is strongly dependent upon GSK3beta-mediated phosphorylation of multiple PPP(S/T)P motifs within the membrane-anchored LRP6 intracellular domain. Previously, we showed that the free LRP6 intracellular domain (LRP6-ICD) can activate the Wnt/beta-catenin pathway in a beta-catenin and TCF/LEF-1 dependent manner, as well as interact with and attenuate GSK3beta activity. However, it is unknown if the ability of LRP6-ICD to attenuate GSK3beta activity and modulate activation of the Wnt/beta-catenin pathway requires phosphorylation of the LRP6-ICD PPP(S/T)P motifs, in a manner similar to the membrane-anchored LRP6 intracellular domain. Here we provide evidence that the LRP6-ICD does not have to be phosphorylated at its PPP(S/T)P motif by GSK3beta to stabilize endogenous cytosolic beta-catenin resulting in activation of TCF/LEF-1 and the Wnt/beta-catenin pathway. LRP6-ICD and a mutant in which all 5 PPP(S/T)P motifs were changed to PPP(A)P motifs equivalently interacted with and attenuated GSK3beta activity in vitro, and both constructs inhibited the in situ GSK3beta-mediated phosphorylation of beta-catenin and tau to the same extent. These data indicate that the LRP6-ICD attenuates GSK3beta activity similar to other GSK3beta binding proteins, and is not a result of it being a GSK3beta substrate. Our findings suggest the functional and regulatory mechanisms governing the free LRP6-ICD may be distinct from membrane-anchored LRP6, and that release of the LRP6-ICD may provide a complimentary signaling cascade capable of modulating Wnt-dependent gene expression.

    Funded by: NIA NIH HHS: F31 AG030788, F31 AG030788-04

    Journal of cellular biochemistry 2009;108;4;886-95

  • Downregulated microRNA-200a in meningiomas promotes tumor growth by reducing E-cadherin and activating the Wnt/beta-catenin signaling pathway.

    Saydam O, Shen Y, Würdinger T, Senol O, Boke E, James MF, Tannous BA, Stemmer-Rachamimov AO, Yi M, Stephens RM, Fraefel C, Gusella JF, Krichevsky AM and Breakefield XO

    Department of Neurology, Massachusetts General Hospital, and Neuroscience Program, Harvard Medical School, Boston, Massachusetts 02129, USA.

    Meningiomas, one of the most common human brain tumors, are derived from arachnoidal cells associated with brain meninges, are usually benign, and are frequently associated with neurofibromatosis type 2. Here, we define a typical human meningioma microRNA (miRNA) profile and characterize the effects of one downregulated miRNA, miR-200a, on tumor growth. Elevated levels of miR-200a inhibited meningioma cell growth in culture and in a tumor model in vivo. Upregulation of miR-200a decreased the expression of transcription factors ZEB1 and SIP1, with consequent increased expression of E-cadherin, an adhesion protein associated with cell differentiation. Downregulation of miR-200a in meningiomas and arachnoidal cells resulted in increased expression of beta-catenin and cyclin D1 involved in cell proliferation. miR-200a was found to directly target beta-catenin mRNA, thereby inhibiting its translation and blocking Wnt/beta-catenin signaling, which is frequently involved in cancer. A direct correlation was found between the downregulation of miR-200a and the upregulation of beta-catenin in human meningioma samples. Thus, miR-200a appears to act as a multifunctional tumor suppressor miRNA in meningiomas through effects on the E-cadherin and Wnt/beta-catenin signaling pathways. This reveals a previously unrecognized signaling cascade involved in meningioma tumor development and highlights a novel molecular interaction between miR-200a and Wnt signaling, thereby providing insights into novel therapies for meningiomas.

    Funded by: NCI NIH HHS: CA69246, CA86355, P01 CA069246, P50 CA086355; NINDS NIH HHS: NS24279, P01 NS024279

    Molecular and cellular biology 2009;29;21;5923-40

  • Hypermethylation of APC promoter 1A is associated with moderate activation of Wnt signalling pathway in a subset of colorectal serrated adenomas.

    Fu X, Li J, Li K, Tian X and Zhang Y

    Institute for Digestive Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China.

    Aims: The role of Wnt signalling pathway in serrated adenomas (SAs) remains to be identified. The aim of this study was to determine whether Wnt signalling plays a role in the pathogenesis of SAs, and to clarify the mechanism of Wnt signalling activation in SAs.

    This study investigated immunoreactivities of adenomatous polyposis coli (APC) and beta-catenin, mutations of APC and beta-catenin genes, methylation status of APC promoter 1A in 12 SAs, and compared the findings with normal colorectal mucosa, hyperplastic polyps, traditional adenomas (TAs) and colorectal cancers (CRCs). APC expression was moderately decreased in SAs. Cytoplasmic accumulation of beta-catenin was demonstrated in 41.7% (5/12) of SAs, but membranous immunoreactivity of beta-catenin was lost in only 8.3% (1/12) of SAs. No beta-catenin mutation was detected in any of 12 SAs, and only one SA was found to be positive for APC gene mutation. Complete methylation of APC promoter 1A was found in 41.7% (5/12) of SAs, but in no TAs or CRCs.

    Conclusions: Hypermethylation of APC promoter 1A, instead of mutations involving APC and beta-catenin, contributes to moderate activation of Wnt signalling in a subset of SAs.

    Histopathology 2009;55;5;554-63

  • Nonstructural 5A protein activates beta-catenin signaling cascades: implication of hepatitis C virus-induced liver pathogenesis.

    Park CY, Choi SH, Kang SM, Kang JI, Ahn BY, Kim H, Jung G, Choi KY and Hwang SB

    National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Dongan-gu, Anyang, Republic of Korea.

    The nonstructural 5A (NS5A) protein of hepatitis C virus (HCV) has been implicated in HCV-induced liver pathogenesis. Wnt/beta-catenin signaling has also been involved in tumorigenesis. To elucidate the molecular mechanism of HCV pathogenesis, we examined the potential effects of HCV NS5A protein on Wnt/beta-catenin signal transduction cascades.

    Methods: The effects of NS5A protein on beta-catenin signaling cascades in hepatic cells were investigated by luciferase reporter gene assay, confocal microscopy, immunoprecipitation assay, and immunoblot analysis.

    Results: beta-Catenin-mediated transcriptional activity is elevated by NS5A protein, in the context of HCV replication, and by infection of cell culture-produced HCV. NS5A protein directly interacts with endogenous beta-catenin and colocalizes with beta-catenin in the cytoplasm. NS5A protein inactivates glycogen synthase kinase 3beta and increases subsequent accumulation of beta-catenin in HepG2 cells. beta-Catenin was also accumulated in HCV patients' liver tissues. In addition, the accumulation of beta-catenin in HCV replicon cells requires both activation of phosphatidylinositol 3-kinase and inactivation of GSK3beta.

    Conclusions: NS5A activates beta-catenin signaling cascades through increasing the stability of beta-catenin. This modulation is accomplished by the protein interplay between viral and cellular signaling transducer. These data suggest that NS5A protein may directly be involved in Wnt/beta-catenin-mediated liver pathogenesis.

    Journal of hepatology 2009;51;5;853-64

  • PPARgamma and Wnt/beta-Catenin pathway in human breast cancer: expression pattern, molecular interaction and clinical/prognostic correlations.

    Jiang Y, Zou L, Zhang C, He S, Cheng C, Xu J, Lu W, Zhang Y, Zhang H, Wang D and Shen A

    Department of General Surgery, Zhongshan Hospital, Fudan University, 200032 Shanghai, China. jiangy05@yahoo.com

    Purpose: Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor expressed in a large number of human cancers and plays important roles in breast cancer cell proliferation. Its association with clinicopathologic features and Wnt/beta-Catenin signaling pathway, a crucial factor in embryonic and malignant development, in breast cancer has not been reported systematically. In the present study, expression patterns, interaction and the correlations with clinical/prognostic factors of PPARgamma and beta-Catenin were investigated among patients with breast cancer.

    Methods: Using immunohistochemistry, we performed a study on 70 patient-derived human breast tumors and compared the protein expression levels of PPARgamma, beta-Catenin and Ki-67. Correlations were then analyzed between IHC-assessed level of these molecules and major clinicopathologic variables and survival. Furthermore, western blot (WB) analysis before and after immunoprecipitation with PPARgamma and beta-Catenin were performed on breast cancer tissues and cell lines to evaluate their protein level and molecular interaction.

    Results: We showed that PPARgamma expression was of significant prognostic value in the outcome of breast carcinomas, which positively correlated with ER status (P = 0.012) and inversely associated with histologic grade (P = 0.012), tumor size (P = 0.007), axillary lymph node status (P = 0.044), TNM stage (P = 0.026), Ki-67 (P = 0.006) and abnormal beta-Catenin expression (P = 0.023), whereas no correlation was seen between PPARgamma and age (P = 0.513), histology (P = 0.764), PR (P = 0.099) or HER-2 status (P = 0.175). Kaplan-Meier survival curves of the study population showed that high expression level of PPARgamma significantly correlated with long-term survival. Molecular interaction could also be demonstrated between PPARgamma and beta-Catenin both in breast cancer cell lines and tissue samples.

    Conclusions: On the basis of these results, we suggested that PPARgamma might serve as a future target for the development of novel treatments in breast cancer.

    Journal of cancer research and clinical oncology 2009;135;11;1551-9

  • [Significance of beta-catenin and Cyclin D1 express in glioma].

    Zhang ZQ, Chen HQ, Chen YH and Cheng XF

    Department of Neurosurgery, The 161st Hospital of PLA, Wuhan 430010, China. zzq882211@sina.com

    Aim: To investigate the expression and the significance of beta-catenin and Cyclin D1 in gliomas.

    Methods: The SABC immunohistochemistry were used to detect the expression of beta-catenin and Cyclin D1 in 49 brain gliomas and 5 normal brain tissues.

    Results: The beta-catenin positive ratio in normal brain tissues and glioma samples are 2/5 and 38/49(P<0.01) respectively, and the Cyclin D1 positive ratio in normal brain tissues and gliomas are 1/5 and 42/49(P<0.01); Compared with the normal brain tissue, both the immunohistochemical expression of beta-catenin and Cyclin D1 were up-regulated(P<0.05), and the expression of beta-catenin and Cyclin D1 between the normal brain tissues and gliomas exhibited significantly difference (P<0.01).

    Conclusion: beta-catenin and Cyclin D1 increased in gliomas may be precipitate the tumorigenesis of glioma.

    Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology 2009;25;11;1010-2

  • Twenty bone-mineral-density loci identified by large-scale meta-analysis of genome-wide association studies.

    Rivadeneira F, Styrkársdottir U, Estrada K, Halldórsson BV, Hsu YH, Richards JB, Zillikens MC, Kavvoura FK, Amin N, Aulchenko YS, Cupples LA, Deloukas P, Demissie S, Grundberg E, Hofman A, Kong A, Karasik D, van Meurs JB, Oostra B, Pastinen T, Pols HA, Sigurdsson G, Soranzo N, Thorleifsson G, Thorsteinsdottir U, Williams FM, Wilson SG, Zhou Y, Ralston SH, van Duijn CM, Spector T, Kiel DP, Stefansson K, Ioannidis JP, Uitterlinden AG and Genetic Factors for Osteoporosis (GEFOS) Consortium

    Department of Internal Medicine, Rotterdam, The Netherlands.

    Bone mineral density (BMD) is a heritable complex trait used in the clinical diagnosis of osteoporosis and the assessment of fracture risk. We performed meta-analysis of five genome-wide association studies of femoral neck and lumbar spine BMD in 19,195 subjects of Northern European descent. We identified 20 BMD loci that reached genome-wide significance (GWS; P < 5 x 10(-8)), of which 13 map to regions not previously associated with this trait: 1p31.3 (GPR177), 2p21 (SPTBN1), 3p22 (CTNNB1), 4q21.1 (MEPE), 5q14 (MEF2C), 7p14 (STARD3NL), 7q21.3 (FLJ42280), 11p11.2 (LRP4, ARHGAP1, F2), 11p14.1 (DCDC5), 11p15 (SOX6), 16q24 (FOXL1), 17q21 (HDAC5) and 17q12 (CRHR1). The meta-analysis also confirmed at GWS level seven known BMD loci on 1p36 (ZBTB40), 6q25 (ESR1), 8q24 (TNFRSF11B), 11q13.4 (LRP5), 12q13 (SP7), 13q14 (TNFSF11) and 18q21 (TNFRSF11A). The many SNPs associated with BMD map to genes in signaling pathways with relevance to bone metabolism and highlight the complex genetic architecture that underlies osteoporosis and variation in BMD.

    Funded by: Arthritis Research UK; Canadian Institutes of Health Research; NHLBI NIH HHS: N01-HC-25195, N01HC25195, N02-HL-6-4278; NIA NIH HHS: R01 AR/AG41398; NIAMS NIH HHS: R01 AR 050066, R01 AR041398, R01 AR041398-18S1A1, R01 AR050066, R01 AR050066-04; Wellcome Trust

    Nature genetics 2009;41;11;1199-206

  • Overexpression of the novel oncogene SALL4 and activation of the Wnt/beta-catenin pathway in myelodysplastic syndromes.

    Shuai X, Zhou D, Shen T, Wu Y, Zhang J, Wang X and Li Q

    Department of Hematology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100730, PR China.

    Myelodysplastic syndromes (MDS) are a group of heterogeneous clonal stem cell diseases with a tendency to progress to leukemic transformation. The cytogenetic and molecular pathogenesis of MDS has not been well understood. SALL4, a newly identified oncogene, modulates stem cell pluripotency and self-renewal capability in embryonic development and also plays a role in leukemogenesis. Overexpression of SALL4 induces MDS-like features and subsequent leukemic progression in transgenic mice. Here, we examined SALL4 expression levels in bone marrow mononuclear cells from MDS patients, acute myeloid leukemia (AML) patients, and normal control subjects using a semiquantitative reverse transcription polymerase chain reaction. Higher levels of SALL4 expression were seen in MDS and AML samples than in control samples. The expression level of SALL4 positively correlated with those of MYC and CCND1, both of which are downstream target genes in the Wnt/beta-catenin pathway. We therefore propose that SALL4 plays a critical role in the pathogenesis of MDS by causing the aberrant activation of the Wnt/beta-catenin pathway.

    Cancer genetics and cytogenetics 2009;194;2;119-24

  • Beta-catenin regulates vitamin C biosynthesis and cell survival in murine liver.

    Nejak-Bowen KN, Zeng G, Tan X, Cieply B and Monga SP

    Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15216, USA.

    Because the Wnt/beta-catenin pathway plays multiple roles in liver pathobiology, it is critical to identify gene targets that mediate such diverse effects. Here we report a novel role of beta-catenin in controlling ascorbic acid biosynthesis in murine liver through regulation of expression of regucalcin or senescence marker protein 30 and L-gulonolactone oxidase. Reverse transcription-PCR, Western blotting, and immunohistochemistry demonstrate decreased regucalcin expression in beta-catenin-null livers and greater expression in beta-catenin overexpressing transgenic livers, HepG2 hepatoma cells (contain constitutively active beta-catenin), regenerating livers, and in hepatocellular cancer tissues that exhibit beta-catenin activation. Interestingly, coprecipitation and immunofluorescence studies also demonstrate an association of beta-catenin and regucalcin. Luciferase reporter and chromatin immunoprecipitation assays verified a functional TCF-4-binding site located between -163 and -157 (CTTTGCA) on the regucalcin promoter to be critical for regulation by beta-catenin. Significantly lower serum ascorbate levels were observed in beta-catenin knock-out mice secondary to decreased expression of regucalcin and also of L-gulonolactone oxidase, the penultimate and last (also rate-limiting) steps in the synthesis of ascorbic acid, respectively. These mice also show enhanced basal hepatocyte apoptosis. To test if ascorbate deficiency secondary to beta-catenin loss and regucalcin decrease was contributing to apoptosis, beta-catenin-null hepatocytes or regucalcin small interfering RNA-transfected HepG2 cells were cultured, which exhibited significant apoptosis that was alleviated by the addition of ascorbic acid. Thus, through regucalcin and L-gulonolactone oxidase expression, beta-catenin regulates vitamin C biosynthesis in murine liver, which in turn may be one of the mechanisms contributing to the role of beta-catenin in cell survival.

    Funded by: NCI NIH HHS: 1R01CA124414, R01 CA124414; NIDDK NIH HHS: 1R01DK62277, R01 DK062277

    The Journal of biological chemistry 2009;284;41;28115-27

  • Activation of beta-catenin signalling increases StarD7 gene expression in JEG-3 cells.

    Rena V, Angeletti S, Panzetta-Dutari G and Genti-Raimondi S

    Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Córdoba, Argentina.

    StarD7 gene encodes a protein that belongs to the StAR-related lipid transfer proteins involved in intracellular transport and metabolism of lipids. It has been previously documented that StarD7 has a wide-spread mRNA expression in trophoblastic tissues and several tumour cell lines with highest levels in both choriocarcinoma JEG-3 and JAR cells, hepatocellular carcinoma HepG2, and colorectal adenocarcinoma HT-29 cells. To understand the molecular mechanisms that regulate the expression of the human StarD7 gene, we have cloned and characterized the 5'-flanking region of the gene. Transient transfections of several 5'deleted StarD7-promoter-firefly luciferase constructs into JEG-3 cells indicated that the -312/+157 region contains the gene minimal promoter. In addition, sequence analysis of a 1.6kb gene fragment revealed the presence of a TATA-less promoter as well as multiple regulatory motifs, including one regulatory element corresponding to the T-cell factor 4 (TCF4) binding site. Inhibition of glycogen synthase kinase-3beta (GSK3beta), a component of Wnt/beta-catenin signalling, increased both StarD7 mRNA and protein expression as well as its promoter activity. Co-transfection experiments in JEG-3 cell line revealed that the StarD7 promoter is activated by TCF4 transcription factor and by its beta-catenin coactivator. Moreover, site-directed mutagenesis of the TCF4 site located -614/-608bp relative to the transcription start site markedly diminished StarD7 promoter activity. Chromatin immunoprecipitation analysis demonstrated that beta-catenin and TCF4 are bound in vivo to the StarD7 gene promoter in JEG-3 cells treated with lithium chloride. Collectively, these studies show that beta-catenin and TCF4 activate the human StarD7 gene interacting with its promoter region through Wnt/beta-catenin signalling.

    Placenta 2009;30;10;876-83

  • Chronic hypoxia activates the Akt and beta-catenin pathways in human macrophages.

    Deguchi JO, Yamazaki H, Aikawa E and Aikawa M

    Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.

    Objective: Macrophage activation contributes importantly to the pathogenesis of inflammatory diseases including atherosclerosis. Macrophages exist chronically under moderate hypoxia (2% to 5% O(2)) in inflamed tissues such as atherosclerotic plaques. However, macrophage phenotypes in such environments remain incompletely understood. This study tested the hypothesis that chronic moderate hypoxia induces macrophage activation and explored the underlying mechanisms.

    We cultured primary human macrophages derived from peripheral blood monocytes in moderate hypoxia (2% O(2) tension) or normoxia (21% O(2)) for 10 days. Moderate hypoxia did not affect macrophage differentiation assessed via expression levels of scavenger receptor A. Chronic moderate hypoxia, but not normoxia, activated Akt and inactivated GSK-3beta, a negative effector of Akt, thus allowing nuclear translocation of beta-catenin. 2% O(2) tension increased accumulation of hypoxia-inducible factors 1 alpha (HIF-1 alpha) transiently at 3 to 5 days. Hypoxia induced mRNA expression of the beta-catenin-associated genes: MMP-7, CD44, and c-Myc. RNAi of TCF7L2, a cofactor of beta-catenin, suppressed MMP-7 expression induced by hypoxia. Inhibition of Akt phosphorylation with LY294002 abolished hypoxia-induced GSK-3beta inactivation, beta-catenin activation, and MMP-7 expression. Macrophages under hypoxia were more resistant for oxLDL-induced apoptosis. Moreover, phospho-Akt colocalized with MMP-7 and CD44 expression in macrophages of human atherosclerotic plaques.

    Conclusions: Chronic moderate hypoxia induces macrophage activation via the Akt and beta-catenin pathways, providing new insight into the pathogenesis of inflammatory diseases.

    Funded by: NHLBI NIH HHS: HL66086

    Arteriosclerosis, thrombosis, and vascular biology 2009;29;10;1664-70

  • HMGA1 is induced by Wnt/beta-catenin pathway and maintains cell proliferation in gastric cancer.

    Akaboshi S, Watanabe S, Hino Y, Sekita Y, Xi Y, Araki K, Yamamura K, Oshima M, Ito T, Baba H and Nakao M

    Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan.

    The development of stomach cancer is closely associated with chronic inflammation, and the Wnt/beta-catenin signaling pathway is activated in most cases of this cancer. High-mobility group A (HMGA) proteins are oncogenic chromatin factors that are primarily expressed not only in undifferentiated tissues but also in various tumors. Here we report that HMGA1 is induced by the Wnt/beta-catenin pathway and maintains proliferation of gastric cancer cells. Specific knockdown of HMGA1 resulted in marked reduction of cell growth. The loss of beta-catenin or its downstream c-myc decreased HMGA1 expression, whereas Wnt3a treatment increased HMGA1 and c-myc transcripts. Furthermore, Wnt3a-induced expression of HMGA1 was inhibited by c-myc knockdown, suggesting that HMGA1 is a downstream target of the Wnt/beta-catenin pathway. Enhanced expression of HMGA1 coexisted with the nuclear accumulation of beta-catenin in about 30% of gastric cancer tissues. To visualize the expression of HMGA1 in vivo, transgenic mice expressing endogenous HMGA1 fused to enhanced green fluorescent protein were generated and then crossed with K19-Wnt1/C2mE mice, which develop gastric tumors through activation of both the Wnt and prostaglandin E2 pathways. Expression of HMGA1-enhanced green fluorescent protein was normally detected in the forestomach, along the upper border of the glandular stomach, but its expression was also up-regulated in cancerous glandular stomach. These data suggest that HMGA1 is involved in proliferation and gastric tumor formation via the Wnt/beta-catenin pathway.

    The American journal of pathology 2009;175;4;1675-85

  • Malignant progression of invasive tumour cells seen in hypoxia present an accumulation of beta-catenin in the nucleus at the tumour front.

    Demir R, Dimmler A, Naschberger E, Demir I, Papadopoulos T, Melling N, Sturzl M and Hohenberger W

    University of Erlangen, Department of Surgery, Krankenhausstrasse 12, D-91054 Erlangen, Germany. resit.demir@uk-erlangen.de

    Of all processes involved in tumour progression, local invasion and formation of metastases are the clinically most relevant but the scientifically least well understood at their molecular level. The loss of cell adhesion, then tumour cell migration with changes in the cytoskeleton, invasion and metastatic dissemination are the steps of the "metastatic cascade". The E-cadherin-catenin complex plays a key role in cell adhesion thus building the first step in malignant progression. In many epithelial cancers, E-cadherin is lost concomitantly with tumour progression. Thus beta-catenin dissociates in the cytoplasm and accumulates in the nucleus as a transcription factor. Recent experimental progress has identified that tumour hypoxia not only induces tumour angiogenesis, but also modulates malignant progression to initiate tumour invasion and metastasis. It was hypothesised that hypoxia within tumours causes dysfunction of the E-cadherin-catenin complex with an accumulation of beta-catenin in the nucleus and produces an invasive phenotype of tumour cells. For this purpose fertilized chicken eggs were incubated for ten days in normoxic conditions. Subsequently colon carcinoma cells (SW-480) were placed on the chorioallantoic membrane. During the following six days the eggs were incubated either in normoxic conditions or in stepwise decreasing hypoxic conditions. SW-480 colon carcinoma cells did not invade the epithelial layer in normoxic conditions. beta-catenin was membrane bound or in the cytoplasm. The nuclei were regularly omitted. In contrast, an invasion through the epithelial layer into the mesoderm was already seen after three days when incubated in hypoxic conditions. beta-catenin was membrane bound in non-invasive regions of the tumour nodule but there was an accumulation of beta-catenin in the nucleus in the invasive tumour front. Hypoxia seems to be responsible for accumulation of beta-catenin in the nucleus which is accompanied by a more invasive phenotype of tumour cells at the tumour front.

    Experimental and molecular pathology 2009;87;2;109-16

  • Aurora kinase A is a target of Wnt/beta-catenin involved in multiple myeloma disease progression.

    Dutta-Simmons J, Zhang Y, Gorgun G, Gatt M, Mani M, Hideshima T, Takada K, Carlson NE, Carrasco DE, Tai YT, Raje N, Letai AG, Anderson KC and Carrasco DR

    Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.

    Multiple myeloma (MM) is a cancer of plasma cells with complex molecular characteristics that evolves from monoclonal gammopathy of undetermined significance, a highly prevalent premalignant condition. MM is the second most frequent hematologic cancer in the United States, and it remains incurable, thereby highlighting the need for new therapeutic approaches, particularly those targeting common molecular pathways involved in disease progression and maintenance, shared across different MM subtypes. Here we report that Wnt/beta-catenin is one such pathway. We document the involvement of beta-catenin in cell-cycle regulation, proliferation, and invasion contributing to enhanced proliferative and metastatic properties of MM. The pleiotropic effects of beta-catenin in MM correlate with its transcriptional function, and we demonstrate regulation of a novel target gene, Aurora kinase A, implicating beta-catenin in G2/M regulation. beta-catenin and Aurora kinase A are present in most MM but not in normal plasma cells and are expressed in a pattern that parallels progression from monoclonal gammopathy of undetermined significance to MM. Our data provide evidence for a novel functional link between beta-catenin and Aurora kinase A, underscoring a critical role of these pathways in MM disease progression.

    Blood 2009;114;13;2699-708

  • Prognostic significance and molecular associations of 18q loss of heterozygosity: a cohort study of microsatellite stable colorectal cancers.

    Ogino S, Nosho K, Irahara N, Shima K, Baba Y, Kirkner GJ, Meyerhardt JA and Fuchs CS

    Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Brigham and Women's Hospital, Harvard Medical School, 44 Binney St, Room JF-215C, Boston, MA 02115 USA. shuji_ogino@dfci.harvard.edu

    Purpose: Loss of heterozygosity (LOH) at chromosome 18q frequently occurs late during colon cancer development and is inversely associated with microsatellite instability (MSI). 18q LOH has been reported to predict shorter survival in patients with colorectal cancer, whereas MSI-high status has been associated with superior prognosis. However, it is unclear whether 18q LOH in colorectal cancer has any prognostic implication independent of MSI status and other potential predictors of clinical outcome.

    Among 555 non-MSI-high colorectal cancers (stage I to IV) in two independent prospective cohort studies, we examined 18q LOH in relation to other molecular events and patient survival. Cox proportional hazard models computed hazard ratio of death, adjusted for clinical and tumoral characteristics, including KRAS, BRAF, PIK3CA, beta-catenin, p53, CpG island methylator phenotype, LINE-1 methylation, and John Cunningham (JC) virus T antigen.

    Results: In multivariate logistic regression, 18q LOH was independently associated with JC virus T antigen (odds ratio [OR] = 1.93; P = .0077), body mass index > or = 30 kg/m(2) (obesity; OR = 2.01; P = .014), high tumor grade (OR = 0.40; P = .018), KRAS mutation (OR = 0.66; P = .40), and LINE-1 hypomethylation (for a 30% decrease; OR = 1.92; P = .045). Five-year colorectal cancer-specific survival was 75% among patients with 18q LOH-positive tumors and 74% among those with 18q LOH-negative tumors (log-rank P = .80). Five-year overall survival was 70% among patients with 18q LOH-positive tumors and 68% among those with 18q LOH-negative tumors (log-rank P = .54). Multivariate analysis did not show prognostic significance of 18q LOH.

    Conclusion: In our large prospective study of patients with non-MSI-high colorectal cancer, 18q LOH or allelic imbalance was not associated with patient survival.

    Funded by: NCI NIH HHS: K07 CA097992, K07 CA122826, K07 CA97992, P01 CA055075, P01 CA087969, P01 CA55075, P01 CA87969, P50 CA127003

    Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2009;27;27;4591-8

  • The regulation of vascular endothelial growth factor-induced microvascular permeability requires Rac and reactive oxygen species.

    Monaghan-Benson E and Burridge K

    Department of Cell and Developmental Biology and Lineberger Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599-7295, USA. ebenson@med.unc.edu

    Vascular permeability is a complex process involving the coordinated regulation of multiple signaling pathways in the endothelial cell. It has long been documented that vascular endothelial growth factor (VEGF) greatly enhances microvascular permeability; however, the molecular mechanisms controlling VEGF-induced permeability remain unknown. Treatment of microvascular endothelial cells with VEGF led to an increase in reactive oxygen species (ROS) production. ROS are required for VEGF-induced permeability as treatment with the free radical scavenger, N-acetylcysteine, inhibited this effect. Additionally, treatment with VEGF caused ROS-dependent tyrosine phosphorylation of both vascular-endothelial (VE)-cadherin and beta-catenin. Rac1 was required for the VEGF-induced increase in permeability and adherens junction protein phosphorylation. Knockdown of Rac1 inhibited VEGF-induced ROS production consistent with Rac lying upstream of ROS in this pathway. Collectively, these data suggest that VEGF leads to a Rac-mediated generation of ROS, which, in turn, elevates the tyrosine phosphorylation of VE-cadherin and beta-catenin, ultimately regulating adherens junction integrity.

    Funded by: NCI NIH HHS: T32-CA-09156-34; NHLBI NIH HHS: HL045100, HL080166, P01 HL045100, P01 HL080166

    The Journal of biological chemistry 2009;284;38;25602-11

  • MicroRNA-122a functions as a novel tumor suppressor downstream of adenomatous polyposis coli in gastrointestinal cancers.

    Wang X, Lam EK, Zhang J, Jin H and Sung JJ

    Department of Biology and Chemistry, City University of Hong Kong, Hong Kong, China.

    Aberrant regulation of APC/beta-catenin signaling pathway is common in the pathogenesis of colorectal and other cancers. Targets regulated by APC/beta-catenin signaling pathway play crucial roles in cancer development. In the current study, we aimed to illustrate the influence of APC/beta-catenin signaling pathway on expression of microRNAs, one new group of players important to carcinogenesis. Restoration of APC function in colorectal cancer cells led to the deregulation of several cancer-related microRNAs, such as miR-122a which was recognized as the liver-specific microRNA. MiR-122a was down-regulated in gastrointestinal cancer cell lines as well as primary carcinoma tissues. Inhibition of miR-122a could reverse wild-type APC-induced growth inhibition of gastrointestinal cancer cells while miR-122a mimic inhibited cell growth. In summary, we identified some cancer-related microRNAs regulated by APC/beta-catenin signaling pathway. The down-regulation of miR-122a mediated by aberrant APC/beta-catenin signaling is important to the pathogenesis of gastrointestinal cancers.

    Biochemical and biophysical research communications 2009;387;2;376-80

  • Daxx positively modulates beta-catenin/TCF4-mediated transcriptional potential.

    Huang YS and Shih HM

    Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, ROC.

    Constitutive activation of the transcription factor TCF4 activity by mutated APC or beta-catenin contributes to cell neoplastic transformation. While numerous proteins were identified to activate TCF4-dependent activity via beta-catenin interaction, little is known about factors directly acting on TCF4. Here we report that Daxx binds to TCF4 and potentiates beta-catenin/TCF4-mediated transcriptional activation and target gene expression. Binding studies revealed that Daxx-TCF4 interaction is through the C-terminal domain of Daxx and TCF4 segment containing amino acid residue 269-327. Alteration of Daxx levels in cells by overexpression or RNA interference resulted in an increase or decrease of the beta-catenin/TCF4-dependent transactivation activity and target gene expression, respectively. Furthermore, TCF4-(269-327) segment acts as a dominantly negative mutant by blocking Daxx-TCF4 interaction and TCF4-mediated transactivation potential. Together, our results suggest that Daxx functions as a positive coregulator in modulating the beta-catenin/TCF4-dependent transcriptional potential via TCF4 interaction.

    Biochemical and biophysical research communications 2009;386;4;762-8

  • A lentivirus-mediated genetic screen identifies dihydrofolate reductase (DHFR) as a modulator of beta-catenin/GSK3 signaling.

    Klinghoffer RA, Frazier J, Annis J, Berndt JD, Roberts BS, Arthur WT, Lacson R, Zhang XD, Ferrer M, Moon RT and Cleary MA

    Rosetta Inpharmatics, LLC, Seattle, Washington, United States of America. richard_klinghoffer@merck.com

    The multi-protein beta-catenin destruction complex tightly regulates beta-catenin protein levels by shuttling beta-catenin to the proteasome. Glycogen synthase kinase 3beta (GSK3beta), a key serine/threonine kinase in the destruction complex, is responsible for several phosphorylation events that mark beta-catenin for ubiquitination and subsequent degradation. Because modulation of both beta-catenin and GSK3beta activity may have important implications for treating disease, a complete understanding of the mechanisms that regulate the beta-catenin/GSK3beta interaction is warranted. We screened an arrayed lentivirus library expressing small hairpin RNAs (shRNAs) targeting 5,201 human druggable genes for silencing events that activate a beta-catenin pathway reporter (BAR) in synergy with 6-bromoindirubin-3'oxime (BIO), a specific inhibitor of GSK3beta. Top screen hits included shRNAs targeting dihydrofolate reductase (DHFR), the target of the anti-inflammatory compound methotrexate. Exposure of cells to BIO plus methotrexate resulted in potent synergistic activation of BAR activity, reduction of beta-catenin phosphorylation at GSK3-specific sites, and accumulation of nuclear beta-catenin. Furthermore, the observed synergy correlated with inhibitory phosphorylation of GSK3beta and was neutralized upon inhibition of phosphatidyl inositol 3-kinase (PI3K). Linking these observations to inflammation, we also observed synergistic inhibition of lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines (TNFalpha, IL-6, and IL-12), and increased production of the anti-inflammatory cytokine IL-10 in peripheral blood mononuclear cells exposed to GSK3 inhibitors and methotrexate. Our data establish DHFR as a novel modulator of beta-catenin and GSK3 signaling and raise several implications for clinical use of combined methotrexate and GSK3 inhibitors as treatment for inflammatory disease.

    PloS one 2009;4;9;e6892

  • CD24 is a novel predictor for poor prognosis of hepatocellular carcinoma after surgery.

    Yang XR, Xu Y, Yu B, Zhou J, Li JC, Qiu SJ, Shi YH, Wang XY, Dai Z, Shi GM, Wu B, Wu LM, Yang GH, Zhang BH, Qin WX and Fan J

    Liver Cancer Institute, Zhong Shan Hospital and Shanghai Medical School, Fudan University, Key Laboratory for Carcinogenesis & Cancer Invasion, Chinese Ministry of Education, Shanghai, People's Republic of China.

    Purpose: To investigate the role of CD24 in tumor invasion and prognostic significance in hepatocellular carcinoma (HCC).

    CD24 expression was measured in stepwise metastatic HCC cell lines, tumor, peritumoral tissues, and normal liver tissues by quantitative real-time PCR and Western blot. The role of CD24 in HCC was investigated by CD24 depletion using small interfering RNA. Tumor tissue microarrays of 314 HCC patients who underwent resection between 1997 and 2000 were used to detect expression of CD24, beta-catenin, and proliferating cell nuclear antigen. Prognostic significance was assessed using Kaplan-Meier survival estimates and log-rank tests.

    Results: CD24 was overexpressed in the highly metastatic HCC cell line and in tumor tissues of patients with recurrent HCC. Depletion of CD24 caused a notable decrease in cell proliferation, migration, and invasiveness in vitro. Univariate and multivariate analyses revealed that CD24 was a significant predictor for overall survival and relapse-free survival. CD24 expression was correlated with poor prognosis independent of alpha-fetoprotein, tumor-node-metastasis stage, and Edmondson stage. High CD24 expression was significantly associated with cytoplasmic and nuclear accumulation of beta-catenin (P = 0.023), high tumor proliferative status (P = 0.018), and diffused intrahepatic recurrence and distant metastasis (P = 0.026). Adjuvant transcatheter arterial chemoembolization after surgery reduced the rate of early recurrence (<or=1 year) in CD24(+) HCC patients (P = 0.024) but had no significant effect in CD24(-) patients (P = 0.284).

    Conclusions: Overexpression of CD24 in HCC was associated with high invasiveness and metastatic potential, high tumor proliferation status, and activation of the Wnt/beta-catenin pathway. CD24 may be a novel predictor for poor prognosis of HCC patients after surgery.

    Clinical cancer research : an official journal of the American Association for Cancer Research 2009;15;17;5518-27

  • Beta-catenin mutation does not seem to have an effect on the tumorigenesis of pediatric rhabdomyosarcomas.

    Bouron-Dal Soglio D, Rougemont AL, Absi R, Giroux LM, Sanchez R, Barrette S and Fournet JC

    Departments of Pathology, CHU Sainte-Justine, 3175 chemin de la Côte Sainte-Catherine, Montréal, QC, Canada. dorothee.dal_soglio.hsj@ssss.gouv.qc.ca

    Involvement of the Wnt signal transduction pathway has been shown in different pediatric embryonal tumors, such as hepatoblastoma, nephroblastoma, pancreatoblastoma, and medulloblastoma. There are few data available on the status of beta-catenin in rhabdomyosarcoma (RMS), another pediatric embryonal tumor. The aims of this study were 1st to verify the status of the exon 3 of CTNNB1 and 2nd to assess the usefulness of beta-catenin immunostaining in a small series of 8 embryonal RMS, 3 alveolar RMS, and 1 sclerosing RMS (SRMS). Sequence analysis revealed no mutations in the exon 3 of CTNNB1 in all the tumors studied. All RMS showed a cytoplasmic beta-catenin staining with cytoplasmic membrane reinforcement and no nuclear delocalization. We conclude that there is no evidence of beta-catenin mutation in the genesis of rhabdomyosarcoma and that beta-catenin does not represent a useful immunomarker to help distinguish between embryonal RMS and alveolar RMS.

    Pediatric and developmental pathology : the official journal of the Society for Pediatric Pathology and the Paediatric Pathology Society 2009;12;5;371-3

  • Candidate gene approach evaluates association between innate immunity genes and breast cancer risk in Korean women.

    Lee JY, Park AK, Lee KM, Park SK, Han S, Han W, Noh DY, Yoo KY, Kim H, Chanock SJ, Rothman N and Kang D

    Department of Preventive Medicine, Seoul National University College of Medicine, 103 Daehak-Ro, Jongno-Gu, Seoul 110-799, Korea.

    Objectives: This study was conducted to investigate the role of common variation in innate immunity-related genes as susceptibility factors to breast cancer risk in Korean women.

    Methods: Total 1536 single-nucleotide polymorphisms (SNPs) in 203 genes were analyzed by Illumina GoldenGate assay in 209 cases and the same numbers of controls. Both SNP and gene-based tests were used to evaluate the association with breast cancer risk. The robustness of results was further evaluated with permutation method, false discovery rate and haplotype analyses.

    Results: Both SNP and gene-based analyses showed promising associations with breast cancer risk for 17 genes: OR10J3, FCER1A, NCF4, CNTNAP1, CTNNB1, KLKB1, ITGB2, ALOX12B, KLK2, IRAK3, KLK4, STAT6, NCF2, CCL1, C1QR1, MBP and NOS1. The most significant association with breast cancer risk was observed for the OR10J3 SNP (rs2494251, P-value = 1.2 x 10(-4)) and FCER1A SNP (rs7548864, P-value = 7.7 x 10(-4)). Gene-based permutation and false discovery rate P-values for OR10J3 SNP (rs2494251) with breast cancer risk were also significant (P = 4 x 10(-5) and 0.008, respectively). Haplotype analyses supported these findings that OR10J3 and FCER1A were most significantly associated with risk for breast cancer (P = 2 x 10(-4) and 0.004, respectively).

    Conclusion: This study suggests that common genetic variants in the OR10J3 and FCER1A be strongly associated with breast cancer risk among Korean women.

    Carcinogenesis 2009;30;9;1528-31

  • CTNNB1 (beta-catenin) mutation is rare in brain tumours but involved as a sporadic event in a brain metastasis.

    Lee CI, Hsu MY, Chou CH, Wang C, Lo YS, Loh JK, Howng SL and Hong YR

    Department of Medical Technology, Fooyin University, Kaohsiung, Taiwan, People's Republic of China.

    Background: The Wnt signaling pathway has been implicated in colon and other cancers. Nevertheless, few or no mutations of CTNNB1 (beta-catenin) have so far been described in brain cancer. We therefore examined the prevalence of constitutive activation of the Wnt signaling pathway in brain cancer specimens as well as cancer cell lines.

    Method: We used polymerase chain reaction PCR and direct sequencing methods to investigate whether mutations in the CTNNB1 phosphorylation sites S33, S37, S41 and T45 were present in 68 brain tumours, including meningioma, astrocytoma, pituitary adenoma, neuroblastoma, metastasis to the brain, and cell lines.

    Findings: CTNNB1 gene mutations were not found in either the original brain tumour specimens or the cell lines. However, a missense mutation of CTNNB1 was identified at residue 33, TCT (Ser) --> TGT (Cys) in a patient with lung metastasis to brain. In addition, in vitro functional assay showed that the S33C mutant of beta-catenin did affect transcriptional activity in a TCF-4-luciferase reporter construct.

    Conclusions: These results indicate that the mutation of exon 3 of the CTNNB1 gene in brain tumours may be a rare event and yet may be required for a small subset of human metastatic brain tumours.

    Acta neurochirurgica 2009;151;9;1107-11

  • Tyrosine-phosphorylation of the 12th armadillo-repeat of beta-catenin is associated with cadherin dysfunction in human cancer.

    Shomori K, Ochiai A, Akimoto S, Ino Y, Shudo K, Ito H and Hirohashi S

    Pathology Division, National Cancer Center Research Institute, 1-1 Tsukiji 5-chome, Chuo-ku, Tokyo, Japan.

    Tyrosine phosphorylation of beta-catenin, an intracytoplasmic cadherin-binding protein, causes disruption of the cadherin-mediated cell adhesion system in cancer cells. We identified that the c-erbB-2 protein activated by TGFalpha was capable of binding to the 12th armadillo repeat (arm12) of beta-catenin with increased phosphorylation-state level. We produced a monoclonal antibody, 4G7, which recognizes a phosphorylated-tyrosine residue (Tyr-654) located at arm12 of beta-catenin. Tyrosine phosphorylation of the arm12 was detected after stimulation with TGFalpha in TMK-1. Immunoprecipitation analyses using 4G7, anti-beta-catenin, alpha-catenin, the c-erbB-2 gene product and phosphotyrosine antibodies indicated that tyrosine phosphorylation of the arm12 was closely correlated with dissociation between E-cadherin/beta-catenin and alpha-catenin or the c-erbB-2 gene product, but not with dissociation between beta-catenin and E-cadherin. Immunocytochemical staining of TMK-1 cells using the 4G7 antibody revealed that tyrosine phosphorylation of the arm12 was localized at cell-cell contact sites of cancer cells transiently and only after TGFalpha treatment. Immunohistochemical localization of the 4G7 antibody was observed in cancer cells at the invasive front where they detached from cancer nests. These findings indicated that the tyrosine phosphorylation of arm12 is a key marker of cadherin dysfunction and the 4G7 antibody may be useful in screening for a beta-catenin phosphorylation ligand or tyrosine kinases.

    International journal of oncology 2009;35;3;517-24

  • Wnt/beta-catenin signaling promotes podocyte dysfunction and albuminuria.

    Dai C, Stolz DB, Kiss LP, Monga SP, Holzman LB and Liu Y

    Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.

    Podocyte dysfunction, one of the major causes of proteinuria, leads to glomerulosclerosis and end stage renal disease, but its underlying mechanism remains poorly understood. Here we show that Wnt/beta-catenin signaling plays a critical role in podocyte injury and proteinuria. Treatment with adriamycin induced Wnt and activated beta-catenin in mouse podocytes. Overexpression of Wnt1 in vivo activated glomerular beta-catenin and aggravated albuminuria and adriamycin-induced suppression of nephrin expression, whereas blockade of Wnt signaling with Dickkopf-1 ameliorated podocyte lesions. Podocyte-specific knockout of beta-catenin protected against development of albuminuria after injury. Moreover, pharmacologic activation of beta-catenin induced albuminuria in wild-type mice but not in beta-catenin-knockout littermates. In human proteinuric kidney diseases such as diabetic nephropathy and focal segmental glomerulosclerosis, we observed upregulation of Wnt1 and active beta-catenin in podocytes. Ectopic expression of either Wnt1 or stabilized beta-catenin in vitro induced the transcription factor Snail and suppressed nephrin expression, leading to podocyte dysfunction. These results suggest that targeting hyperactive Wnt/beta-catenin signaling may represent a novel therapeutic strategy for proteinuric kidney diseases.

    Funded by: NIDDK NIH HHS: DK061408, DK064005, DK071040, R01 DK061408, R01 DK064005, R01 DK071040

    Journal of the American Society of Nephrology : JASN 2009;20;9;1997-2008

  • The COP9 signalosome mediates beta-catenin degradation by deneddylation and blocks adenomatous polyposis coli destruction via USP15.

    Huang X, Langelotz C, Hetfeld-Pechoc BK, Schwenk W and Dubiel W

    Department of General, Visceral, Vascular and Thoracic Surgery, Charité - Universitätsmedizin Berlin, Germany.

    The Wnt/beta-catenin signalling pathway has important roles in normal cellular proliferation, development and angiogenesis. Many malignant transformations, including sporadic colorectal tumours, are caused by constitutive activation of the Wnt route due to mutations in the tumour suppressor protein adenomatous polyposis coli (APC) or the beta-catenin oncogene, ultimately resulting in reduced beta-catenin degradation by the ubiquitin (Ub) proteasome system (UPS). The COP9 signalosome (CSN) regulates the UPS by controlling cullin-RING Ub ligases (CRLs). We show here that the CSN and the beta-catenin destruction complex cooperate in targeting beta-catenin for degradation by the UPS. Together with the CRL that ubiquitinates beta-catenin, they form a supercomplex responsible for beta-catenin degradation. Wnt3A, glycogen synthase kinase 3beta inhibitors or mutation of CSN-mediated deneddylation induce the disassembly of the supercomplex and the accumulation of beta-catenin. Likewise, downregulation of the CSN in HeLa cells leads to retarded degradation of beta-catenin. Additionally, we found that the knockdown of the CSN causes accelerated proteolysis of APC, an essential component of the beta-catenin destruction complex, which is degraded by the UPS as beta-catenin. We show here that APC is stabilised by the Ub-specific protease 15 (USP15) associated with the CSN. This is demonstrated by over-expression of siRNA oligonucleotides against USP15 or by over-expression of an USP15 mutant, which is unable to degrade poly-Ub chains. Thus, the CSN controls the Wnt/beta-catenin signalling by assisting the assembly of beta-catenin-degrading supercomplexes by deneddylation and, simultaneously, by stabilising APC via CSN-associated USP15. The CSN regulates the balance between beta-catenin and APC. Disturbance of this balance can cause cancer by driving cell transformation, tumour angiogenesis and metastasis. A model is provided that proposes a role of CSN-mediated deneddylation in the formation of the beta-catenin-degrading supercomplex and the protection of complex-bound APC via CSN-associated USP15.

    Journal of molecular biology 2009;391;4;691-702

  • PR55 alpha, a regulatory subunit of PP2A, specifically regulates PP2A-mediated beta-catenin dephosphorylation.

    Zhang W, Yang J, Liu Y, Chen X, Yu T, Jia J and Liu C

    Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA.

    A central question in Wnt signaling is the regulation of beta-catenin phosphorylation and degradation. Multiple kinases, including CKI alpha and GSK3, are involved in beta-catenin phosphorylation. Protein phosphatases such as PP2A and PP1 have been implicated in the regulation of beta-catenin. However, which phosphatase dephosphorylates beta-catenin in vivo and how the specificity of beta-catenin dephosphorylation is regulated are not clear. In this study, we show that PP2A regulates beta-catenin phosphorylation and degradation in vivo. We demonstrate that PP2A is required for Wnt/beta-catenin signaling in Drosophila. Moreover, we have identified PR55 alpha as the regulatory subunit of PP2A that controls beta-catenin phosphorylation and degradation. PR55 alpha, but not the catalytic subunit, PP2Ac, directly interacts with beta-catenin. RNA interference knockdown of PR55 alpha elevates beta-catenin phosphorylation and decreases Wnt signaling, whereas overexpressing PR55 alpha enhances Wnt signaling. Taken together, our results suggest that PR55 alpha specifically regulates PP2A-mediated beta-catenin dephosphorylation and plays an essential role in Wnt signaling.

    Funded by: NCI NIH HHS: R21 CA112007, R21 CA112007-01; NIDDK NIH HHS: R01 DK071976, R01 DK071976-01A2, R01DK071976; NIGMS NIH HHS: R01GM079684

    The Journal of biological chemistry 2009;284;34;22649-56

  • The cytological, clinical, and pathological features of the cribriform-morular variant of papillary thyroid carcinoma and mutation analysis of CTNNB1 and BRAF genes.

    Jung CK, Choi YJ, Lee KY, Bae JS, Kim HJ, Yoon SK, Son YI, Chung JH and Oh YL

    Department of Hospital Pathology, Seoul St. Mary's Hospital, The Catholic University of Korea, Republic of Korea.

    Background: The cribriform-morular variant of papillary thyroid carcinoma (CMVPTC) is an unusual subtype of papillary thyroid carcinoma. The goal of this study was to determine the clinicopathological features of CMVPTC and whether the tumor can be diagnosed by fine-needle aspiration cytology.

    Methods: We retrospectively analyzed the clinical appearance and pathological findings in five patients with CMVPTC and sequenced exon 3 of CTNNB1 and exon 15 of BRAF in tumor tissue.

    Results: All patients were young women, 15-34 years of age at the time of the cancer diagnosis. Preoperative cytological examination showed scattered tall columnar cells, fascicular spindle cells, and cribriform and morular patterns in the fine-needle aspirates of the thyroid from the five patients. Grossly, all tumors were well-circumscribed, solid or cystic. Immunohistochemically, most tumor cells showed nuclear expression of thyroid transcription factor-1, estrogen and progesterone receptors, and p53; cytoplasmic expression of cytokeratins 7 and 19, vimentin, and bcl-2; and cytoplasmic and nuclear accumulation of beta-catenin and galectin-3. There was no expression of thyroglobulin, cytokeratin 5/6, or human mesothelial cell-1. However, among these markers, the morular cells showed only positive immunostaining for beta-catenin, galectin-3, p53, and bcl-2. A CTNNB1 mutation was identified in only one case and no BRAF mutation was found in any of the five cases.

    Conclusions: Taken together, these data suggest that CMVPTC can be diagnosed preoperatively, based on careful cytology examination, and shows unique immunohistochemical findings.

    Thyroid : official journal of the American Thyroid Association 2009;19;8;905-13

  • A gene marker panel covering the Wnt and the Ras-Raf-MEK-MAPK signalling pathways allows to detect gene mutations in 80% of early (UICC I) colon cancer stages in humans.

    Scholtka B, Schneider M, Melcher R, Katzenberger T, Friedrich D, Berghof-Jäger K, Scheppach W and Steinberg P

    Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany.

    Background: Very recently a gene marker panel that allows the mutational analysis of APC, CTNNB1, B-RAF and K-RAS was conceived. The aim of the present study was to use the 4-gene marker panel covering the Wnt and Ras-Raf-MEK-MAPK signalling pathways to determine the percentage of sporadic colorectal carcinomas (CRC) carrying at least one of the four above-mentioned genes in a mutated form alone and/or in combination with microsatellite instability (MSI) and to compare the sensitivity of the gene marker panel used in this study with that of gene marker panels previously reported in the scientific literature.

    Methods: CTNNB1 and B-RAF were screened by PCR-single-strand conformation polymorphism analysis and K-RAS gene mutations by restriction fragment length polymorphism analysis. For the mutational analysis of the APC gene mutation cluster region (codons 1243-1567) direct DNA sequencing was performed. The U.S. National Cancer Institute microsatellite panel (BAT25, BAT26, D2S123, D5S346 and D17S250) was used for MSI analysis.

    Results: It could be shown that about 80% of early stage CRC (UICC stages I and II) and over 90% of CRC in the UICC stage IV carried at least one mutated gene and/or showed MSI. No significant increase in the gene mutation frequencies could be determined when comparing tumours in the UICC stage I with those in UICC stage IV.

    Conclusions: When compared with previously published gene marker panels the 4-gene marker panel used in the present study shows an excellent performance, allowing to detect genetic alterations in 80-90% of human sporadic CRC samples analyzed.

    Cancer epidemiology 2009;33;2;123-9

  • Differential protein immunoexpression profiles in appendiceal mucinous neoplasms: a special reference to classification and predictive factors.

    Yoon SO, Kim BH, Lee HS, Kang GH, Kim WH, Kim YA, Kim JE and Chang MS

    Department of Pathology, Seoul National University Boramae Hospital, Seoul, Korea.

    Appendiceal mucinous neoplasms have been the focus of considerable debate in recent years. We histologically classified 70 appendiceal mucinous neoplasms into three categories: 32 mucinous adenoma, 23 mucinous neoplasm of uncertain malignant potential, and 15 mucinous adenocarcinomas. Immunohistochemistry was performed for 24 proteins in different functional categories, specifically, oncogenic proteins (bcl-2, beta-catenin, CEA, C-erbB2, c-kit, Cox-2, Cyclin D1, EGFR, Ki-67, NF-kappaB, VEGF), tumor suppressors (E-cadherin, FHIT, hMLH1, p53, p63, smad4), cell-cycle regulators (p21, p27, p16), and mucin proteins (MUC1, MUC2, MUC5AC, MUC6). Our data showed that 9 out of the 24 proteins were more frequently altered in the mucinous adenocarcinoma group than in the mucinous adenoma group (P<0.05), including beta-catenin (13% in mucinous adenoma vs 60% in mucinous adenocarcinoma), CyclinD1 (44 vs 87%), Ki-67 (high labeling index: 31 vs 67%), NF-kappaB (19 vs 60%), VEGF (16 vs 87%), E-cadherin (0 vs 47%), p53 (6 vs 40%), MUC2 (9 vs 67%), and MUC5AC (3 vs 40%). The distinct immunoexpression profile of mucinous neoplasm of uncertain malignant potential was placed between those of mucinous adenoma and mucinous adenocarcinoma (P<0.05). Moreover, the mucinous adenoma, mucinous neoplasm of uncertain malignant potential, and mucinous adenocarcinoma categories displayed differences in terms of the number of altered markers among the nine proteins (P<0.05; mean 1.4 vs 2.6 vs 5.5, respectively). In mucinous adenocarcinoma, the p53 status was related to disease-free survival and overall survival of patients (P<0.05, both). NF-kappaB status and the number of altered protein markers made statistically marginal impacts on disease-free survival; also beta-catenin loss, on overall survival of patients. In conclusion, protein immunoexpression profiles may facilitate the classification of appendiceal mucinous neoplasms. In our study, the three tumor categories of mucinous adenoma, mucinous neoplasm of uncertain malignant potential, and mucinous adenocarcinoma exhibited distinct immunoexpression profiles. Five and more altered protein markers, p53 overexpression, NF-kappaB positivity, and beta-catenin loss were predictive factors of adverse clinical outcomes in appendiceal mucinous adenocarcinomas.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2009;22;8;1102-12

  • Expression of E-cadherin, beta-catenin and topoisomerase IIalpha in leiomyosarcomas.

    Gogou PN, Batistatou A, Pakos EE, Apostolikas N, Stefanou D and Tsekeris PG

    Department of Radiotherapy, University of Ioannina, Medical School, Ioannnina, Greece.

    Introduction: The expression of E-cadherin, beta-catenin and topoisomerase II has been associated with clinical outcome of several cancers including sarcomas. We aimed to evaluate the expression of these markers in leiomyosarcomas (LMS).

    Paraffin blocks of 19 primary, nonmetastatic LMS were analysed immunohistochemically for the expression of the above-mentioned markers with a cutoff level for positivity of 20% of cell staining.

    Results: Expression of E-cadherin was negative in all LMS. Nuclear expression of beta-catenin was also negative in all cases, while positive cytoplasmic beta-catenin expression was observed in approximately half of the patients. The majority of LMS had expression of topoisomerase IIalpha, although only in 10 patients was this expression in more than 20% of tumour cells. From the analysed factors, tumour size was statistically significantly correlated with relapse-free survival.

    Conclusions: Further evidence with larger series is required in order to determine the implication of these markers in LMS.

    Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico 2009;11;8;548-51

  • Mutational analysis of TP53, PTEN, PIK3CA and CTNNB1/beta-catenin genes in human herpesvirus 8-associated primary effusion lymphoma.

    Boulanger E, Marchio A, Hong SS and Pineau P

    Department of Clinical Immunology, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, Paris, France. emmaboul@ioc.fiocruz.br

    Human herpesvirus 8 (HHV-8)-associated primary effusion lymphoma is a rare non-Hodgkin's lymphoma often associated with Epstein-Barr virus (EBV) infection. Mutations in TP53, PTEN, PIK3CA, CTNNB1/beta-catenin genes and deletion of CDKN2A-ARF (p14(ARF)-p16(NK4a I) ) locus were investigated in sixteen primary primary effusion lymphoma tumors and seven primary effusion lymphoma cell lines using PCR and sequencing. TP53 mutations were detected in one primary primary effusion lymphoma tumor (6.2%) and two primary effusion lymphoma cell lines (28.6%). BC-3 and BCP-1 cell lines showed PTEN gene mutations, associated with a loss of PTEN protein expression in both cases. No mutations were detected in PIK3CA and CTNNB1/beta-catenin hotspot sequences. Only BC-3 contained a homozygous deletion of CDKN2A-ARF locus. Although detected at a higher frequency in primary effusion lymphoma cell lines than in primary primary effusion lymphoma tumors, TP53 and/or PTEN mutations, as well as deletion of CDKN2A-ARF locus are uncommon in primary effusion lymphoma, and are found to correlate with the EBV-negative status of primary effusion lymphoma tumors.

    Haematologica 2009;94;8;1170-4

  • Selective inhibition of prostaglandin E2 receptors EP2 and EP4 induces apoptosis of human endometriotic cells through suppression of ERK1/2, AKT, NFkappaB, and beta-catenin pathways and activation of intrinsic apoptotic mechanisms.

    Banu SK, Lee J, Speights VO, Starzinski-Powitz A and Arosh JA

    Reproductive Endocrinology and Cell Signaling Laboratory, Department of Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843, USA.

    Endometriosis is a benign chronic gynecological disease of reproductive-age women characterized by the presence of functional endometrial tissues outside the uterine cavity. It is an estrogen-dependent disease. Current treatment modalities to inhibit biosynthesis and actions of estrogen compromise menstruation, pregnancy, and the reproductive health of women and fail to prevent reoccurrence of disease. There is a critical need to identify new specific signaling modules for non-estrogen-targeted therapies for endometriosis. In our previous study, we reported that selective inhibition of cyclooxygenase-2 prevented survival, migration, and invasion of human endometriotic epithelial and stromal cells, which was due to decreased prostaglandin E(2) (PGE(2)) production. In this study, we determined mechanisms through which PGE(2) promoted survival of human endometriotic cells. Results of the present study indicate that 1) PGE(2) promotes survival of human endometriotic cells through EP2 and EP4 receptors by activating ERK1/2, AKT, nuclear factor-kappaB, and beta-catenin signaling pathways; 2) selective inhibition of EP2 and EP4 suppresses these cell survival pathways and augments interactions between proapoptotic proteins (Bax and Bad) and antiapoptotic proteins (Bcl-2/Bcl-XL), facilitates the release of cytochrome c, and thus activates caspase-3/poly (ADP-ribose) polymerase-mediated intrinsic apoptotic pathways; and 3) these PGE(2) signaling components are more abundantly expressed in ectopic endometriosis tissues compared with eutopic endometrial tissues during the menstrual cycle in women. These novel findings may provide an important molecular framework for further evaluation of selective inhibition of EP2 and EP4 as potential therapy, including nonestrogen target, to expand the spectrum of currently available treatment options for endometriosis in women.

    Molecular endocrinology (Baltimore, Md.) 2009;23;8;1291-305

  • Requirement of cell cycle and apoptosis regulator 1 for target gene activation by Wnt and beta-catenin and for anchorage-independent growth of human colon carcinoma cells.

    Ou CY, Kim JH, Yang CK and Stallcup MR

    Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California 90089, USA.

    Aberrant Wnt signaling promotes oncogenesis by increasing cellular levels of beta-catenin, which associates with DNA-bound transcription factors and activates Wnt target genes. However, the molecular mechanism by which beta-catenin mediates gene expression is still poorly understood. Here, we show that cell cycle and apoptosis regulator 1 (CCAR1), which was recently shown to function as a transcriptional coactivator for nuclear receptors, also interacts with beta-catenin and enhances the ability of beta-catenin to activate expression of transiently transfected reporter genes. Furthermore, association of CCAR1 with the promoter of an endogenous Wnt/beta-catenin target gene in a colon cancer cell line depends on the presence of beta-catenin. Depletion of CCAR1 inhibits expression of several Wnt/beta-catenin target genes and suppresses anchorage-independent growth of the colon cancer cell line. Thus, CCAR1 is a novel component of Wnt/beta-catenin signaling that plays an important role in transcriptional regulation by beta-catenin and that, therefore, may represent a novel target for therapeutic intervention in cancers involving aberrantly activated Wnt/beta-catenin signaling.

    Funded by: NCI NIH HHS: T32CA009320; NIDDK NIH HHS: DK43093

    The Journal of biological chemistry 2009;284;31;20629-37

  • Activity of the beta-catenin phosphodestruction complex at cell-cell contacts is enhanced by cadherin-based adhesion.

    Maher MT, Flozak AS, Stocker AM, Chenn A and Gottardi CJ

    Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.

    It is well established that cadherin protein levels impact canonical Wnt signaling through binding and sequestering beta-catenin (beta-cat) from T-cell factor family transcription factors. Whether changes in intercellular adhesion can affect beta-cat signaling and the mechanism through which this occurs has remained unresolved. We show that axin, APC2, GSK-3beta and N-terminally phosphorylated forms of beta-cat can localize to cell-cell contacts in a complex that is molecularly distinct from the cadherin-catenin adhesive complex. Nonetheless, cadherins can promote the N-terminal phosphorylation of beta-cat, and cell-cell adhesion increases the turnover of cytosolic beta-cat. Together, these data suggest that cadherin-based cell-cell adhesion limits Wnt signals by promoting the activity of a junction-localized beta-cat phosphodestruction complex, which may be relevant to tissue morphogenesis and cell fate decisions during development.

    Funded by: NIGMS NIH HHS: GM076561, R01 GM076561-04, T32 GM08061; NINDS NIH HHS: R01 NS047191

    The Journal of cell biology 2009;186;2;219-28

  • Endosomal adaptor proteins APPL1 and APPL2 are novel activators of beta-catenin/TCF-mediated transcription.

    Rashid S, Pilecka I, Torun A, Olchowik M, Bielinska B and Miaczynska M

    Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland.

    Canonical Wnt signaling regulates many aspects of cellular physiology and tissue homeostasis during development and in adult organisms. In molecular terms, stimulation by Wnt ligands leads to the stabilization of beta-catenin, its translocation to the nucleus, and stimulation of TCF (T-cell factor)-dependent transcription of target genes. This process is controlled at various stages by a number of regulatory proteins, including transcriptional activators and repressors. Here we demonstrate that the endosomal proteins APPL1 and APPL2 are novel activators of beta-catenin/TCF-mediated transcription. APPL proteins are multifunctional adaptors and effectors of the small GTPase Rab5, which localize to a subpopulation of early endosomes but are also capable of nucleocytoplasmic shuttling. Overexpression of APPL1 or APPL2 protein stimulates the activity of beta-catenin/TCF-dependent reporter construct, whereas silencing of APPL1 reduces it. Both APPL proteins interact directly with Reptin, a transcriptional repressor binding to beta-catenin and HDAC1 (histone deacetylase 1), and this interaction was mapped to the pleckstrin homology domain of APPL1. Moreover, APPL proteins are present in an endogenous complex containing Reptin, beta-catenin, HDAC1, and HDAC2. Overexpression of either APPL protein relieves Reptin-dependent transcriptional repression and correlates with the reduced amounts of HDACs and beta-catenin associated with Reptin as well as with the lower levels of Reptin and HDAC1 on the promoters of beta-catenin target genes. We propose that APPL proteins exert their stimulatory effects on beta-catenin/TCF-dependent transcription by decreasing the activity of a Reptin-containing repressive complex.

    Funded by: Howard Hughes Medical Institute; Wellcome Trust: 076469, 076469/Z/05/Z

    The Journal of biological chemistry 2009;284;27;18115-28

  • A colorectal cancer expression profile that includes transforming growth factor beta inhibitor BAMBI predicts metastatic potential.

    Fritzmann J, Morkel M, Besser D, Budczies J, Kosel F, Brembeck FH, Stein U, Fichtner I, Schlag PM and Birchmeier W

    Max Delbrueck Center for Molecular Medicine, Berlin, Germany.

    Much is known about the genes and mutations that cause colorectal cancer (CRC), yet only a few have been associated with CRC metastasis. We performed expression-profiling experiments to identify genetic markers of risk and to elucidate the molecular mechanisms of CRC metastasis.

    Methods: We compared gene expression patterns between metastatic and nonmetastatic stage-matched human colorectal carcinomas by microarray analysis. Correlations between BAMBI and metastasis-free survival were examined by quantitative real-time polymerase chain reaction (PCR) using an independent set of human colon carcinomas. Human colon cancer cell lines were analyzed for BAMBI regulation, cell motility, and experimental metastasis.

    Results: We established a signature of 115 genes that differentiated metastatic from nonmetastatic primary tumors. Among these, the transforming growth factor (TGF) beta inhibitor BAMBI was highly expressed in approximately half of metastatic primary tumors and metastases but not in nonmetastatic tumors. BAMBI is a target of canonical Wnt signaling that involves the beta-catenin coactivator BCL9-2. We observed an inverse correlation between level of BAMBI expression and metastasis-free survival time of patients. BAMBI inhibits TGF-beta signaling and increases migration in colon cancer cells. In mice, overexpression of BAMBI caused colon cancer cells to form tumors that metastasized more frequently to liver and lymph nodes than control cancer cells.

    Conclusions: BAMBI regulates CRC metastasis by connecting the Wnt/beta-catenin and TGF-beta-signaling pathways. The metastatic expression signature we describe, along with BAMBI levels, can be used in prognosis. Developmental signaling pathways appear to act in hierarchies and cooperate in tumor cell migration, invasion, and metastasis.

    Gastroenterology 2009;137;1;165-75

  • Beta-catenin expression in pediatric fibroblastic and myofibroblastic lesions: a study of 100 cases.

    Thway K, Gibson S, Ramsay A and Sebire NJ

    Department of Histopathology, Royal Marsden Hospital, London, United Kingdom. khin.thway@rmh.nhs.uk

    Nuclear immunoreactivity for beta-catenin is a useful adjunct for diagnosis of adult desmoid-type fibromatoses, many of which exhibit mutations within the APC/beta-catenin (Wnt) pathway. Pediatric fibromatoses represent a heterogeneous group of lesions that are diagnostically challenging, especially on biopsy. We studied beta-catenin expression in a variety of pediatric fibroblastic and myofibroblastic lesions. Immunohistochemical nuclear expression of beta-catenin was assessed in 100 tumors. High-level expression of beta-catenin was found in 42% of usual-type or deep fibromatoses (21 of 50). Such expression was not seen in any of the other lesions, including fibrous hamartoma of infancy (0 of 18), juvenile hyaline fibromatosis (0 of 7), infantile digital fibromatosis (0 of 6), myofibromatosis (0 of 5), lipofibromatosis (0 of 4), calcifying aponeurotic fibroma (0 of 3), palmar-plantar fibromatosis (0 of 2), fibromatosis colli (0 of 1), or torticollis (0 of 1). High-level beta-catenin staining is seen in deep "adult-type" fibromatoses occurring in children, although to a lesser frequency than in adult fibromatoses. This indicates that a subset of deep fibromatoses in childhood shares similar mechanisms of tumorigenesis with those in adults. beta-catenin is not expressed in other common pediatric fibroblastic and myofibroblastic lesions, and the Wnt pathway does not appear to play a role in their pathogenesis.

    Pediatric and developmental pathology : the official journal of the Society for Pediatric Pathology and the Paediatric Pathology Society 2009;12;4;292-6

  • Beta-catenin expression is altered in dysplastic and nondysplastic aberrant crypt foci of human colon.

    Mi B, Wang X, Bai Y, Gong W, Wang X, Geng Y, Wang J, Zhang H and Jiang B

    Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China.

    Purpose: Aberrant crypt foci (ACF) of the colon are possible precursors of adenoma and cancer. beta-catenin alterations are early events in human colorectal carcinogenesis. beta-catenin expression is altered in colorectal cancer, adenoma, and ACF with dysplasia. Here, we describe the expression of beta-catenin in ACF, especially nondysplastic ACF.

    Methods: Rectal chromoscopy with 4% indigo carmine was performed on 418 subjects and 146 biopsy specimens, including 10 dysplastic ACF, 106 nondysplastic ACF, and 30 normal colonic mucosal controls taken under endoscopy. The expression and subcellular distribution of beta-catenin were assessed by immunohistochemistry.

    Results: beta-catenin expression was altered in 1 of 30 (3.3%) normal mucosa, 30 of 106 (28.3%) nondysplastic ACF, and 10 of 10 (100%) dysplastic ACF (P<0.001). Notably, most cells with altered beta-catenin expression in nondysplastic ACF were limited to the bottom of the crypt, where stem cells are located.

    Conclusions: Both dysplastic and nondysplastic ACF have altered beta-catenin expression and play a role in colon tumorigenesis.

    Applied immunohistochemistry & molecular morphology : AIMM 2009;17;4;294-300

  • Collagen type I may influence the expression of E-cadherin and beta-catenin in carcinoma ex-pleomorphic adenoma.

    Araújo VC, Demasi AP, Furuse C, Altemani A, Alves VA, Freitas LL and Araújo NS

    Department of Oral Pathology, São Leopoldo Mandic Research Center, Campinas, São Paulo, Brazil.

    Carcinoma ex-pleomorphic adenoma (CXPA) is an aggressive salivary gland malignancy, usually derived from a long-standing or a recurrent benign tumor, the pleomorphic adenoma (PA). In the context of dynamic reciprocity, changes in the composition and structure of extracellular matrix proteins and cell surface receptors have been frequently associated with dysfunctional adhesion and invasive behavior of tumor cells. It is not fully understood if these changes are involved in the conversion of PA to CXPA. In this study, different progression stages of CXPA were investigated regarding the expression of the major extracellular matrix proteins, collagen type I, and of E-cadherin and beta-catenin, the components of adherens junctions. By immunohistochemical analysis, we have demonstrated that direct contact of tumor cells with fibrillar type I collagen, particularly near the invasive front and in invasive areas prevailing small nests of CXPA cells, could be associated with reduced expression of the E-cadherin and beta-catenin adhesion molecules and with invasive behavior of epithelial, but not of CXPA with myoepithelial component. Our results also suggested that this association could depend on the organization of collagen molecules, being prevented by high-order polymeric structures. These findings could implicate the local microenvironment in the transition from the premalignant PA to invasive CXPA.

    Applied immunohistochemistry & molecular morphology : AIMM / official publication of the Society for Applied Immunohistochemistry 2009;17;4;312-8

  • Expression of beta-catenin and its mechanism of delocalization in intestinal-type early gastric cancer based on mucin expression.

    Lee SH, Kang HJ, Shin DH, Cho DY, Song JM, Lee HC, Kim GH, Song GA, Sol MY, Kim JY, Choi KU, Lee CH, Huh GY and Park do Y

    Department of Pathology, Pusan National University School of Medicine, Busan, Republic of Korea.

    The biological characteristics of intestinal-type early gastric cancers (ICs) differ based on mucin phenotypes. Beta-catenin delocalization is a predictive marker of aggressive biological behavior (submucosal invasion and lymph node metastasis) of ICs. The presumptive causative genetic alterations leading to delocalization of beta-catenin in ICs are still controversial, and there are only a few reports regarding beta-catenin expression in gastric cancer based on mucin phenotypes. Therefore, in the current study, the expression and mechanisms of delocalization of beta-catenin were elucidated on the basis of mucin phenotypes in 109 cases of ICs. There was increased cytoplasmic and nuclear beta-catenin expression (delocalization) in ICs with a predominant intestinal mucin phenotype (ICIP; 46.3% [25/54 cases]) compared to ICs with a predominant gastric mucin phenotype (ICGP; 20% [11/55 cases]). There were no beta-catenin or APC mutations in ICs. APC promoter hypermethylation was present in 49 of 105 (46.7%) cases of ICs. There was a significant relationship between APC promoter hypermethylation and beta-catenin delocalization in ICs, especially in ICIPs. There was no relationship between beta-catenin delocalization and APC gene loss of heterozygosity in ICs. In conclusion, we showed that beta-catenin delocalization was more evident in ICIPs, and APC promoter hypermethylation might play a role in delocalization of beta-catenin, especially in ICIPs.

    Histology and histopathology 2009;24;7;831-8

  • Expression of Notch-1 and alteration of the E-cadherin/beta-catenin cell adhesion complex are observed in primary cutaneous neuroendocrine carcinoma (Merkel cell carcinoma).

    Panelos J, Batistatou A, Paglierani M, Zioga A, Maio V, Santi R, Pimpinelli N, De Giorgi V, Santucci M and Massi D

    Department of Human Pathology and Oncology, University of Florence, Florence, Italy.

    Increasing evidence indicates that Notch signaling contributes to physiological processes, including development and differentiation, as well as tumorigenesis, either as a tumor promoter or suppressor, depending on cellular context, expression levels and cross talk with other signaling systems. Recent studies reported absent or minimal Notch-1 expression in neuroendocrine tumors of the lung and gastrointestinal tract, suggesting a tumor-suppressor function of Notch-1. Merkel cell carcinoma is a rare and highly aggressive primary cutaneous neuroendocrine carcinoma. Because no information is available on Notch-1 expression in this tumor, we have investigated a series of 31 Merkel cell carcinoma for Notch-1 immunoreactivity. Immunoreactivities for E-cadherin and beta-catenin were also analyzed. All but 1 Merkel cell carcinoma (30 of 31) retained cytoplasmic and membrane Notch-1 expression in more than 50% of cells. beta-Catenin displayed a prevalent membrane-associated staining in 30 of 31 cases, and 22 cases showed more than 50% of immunoreactive cells whereas nuclear beta-catenin was seen only in 2 of 31 cases. E-cadherin membranous expression was remarkably low, as only 1 of 26 cases was found positive in more than 50% of cells. In contrast with neuroendocrine tumors in other tissues, evident Notch-1 expression was found in Merkel cell carcinoma. This finding does not support a tumor-suppressor function of Notch-1 in Merkel cell carcinoma. Downregulation of E-cadherin and diffuse membranous beta-catenin expression suggest a dysregulation of the E-cadherin/beta-catenin complex in Merkel cell carcinoma. This may contribute to local invasion and distant metastasis.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2009;22;7;959-68

  • Investigation of BRAF and CTNNB1 activating mutations in adrenocortical tumors.

    Masi G, Lavezzo E, Iacobone M, Favia G, Palù G and Barzon L

    Department of Histology, Microbiology, and Medical Biotechnologies, University of Padua, Padua, Italy.

    Background: Activating mutations of the BRAF oncogene play a central role in the development of various cancer types, but their role in human adrenocortical tumors is unknown. At variance, activating mutations of another oncogene, CTNNB1, which encodes beta-catenin, have been shown to be common events in both benign and malignant adrenocortical tumors.

    Aim: To investigate the prevalence of BRAF and CTNNB1 activating mutations in sporadic adrenocortical tumors.

    Tissue samples from 15 adrenocortical carcinomas and 41 adrenocortical adenomas were investigated for the presence of BRAF and CTNNB1 activating mutations by PCR amplification and direct sequencing.

    Results: An advanced invasive non-functioning adrenocortical carcinoma carried a somatic heterozygous BRAF V600E mutation, while 4 functioning and 4 non-functioning adenomas and 3 functioning carcinomas carried different CTNNB1 activating mutations.

    Conclusions: Activating BRAF somatic mutations may be occasionally found in advanced adrenocortical carcinomas, while CTNNB1 activating mutations are early and common events in adrenal tumorigenesis.

    Journal of endocrinological investigation 2009;32;7;597-600

  • Quercetin inhibit human SW480 colon cancer growth in association with inhibition of cyclin D1 and survivin expression through Wnt/beta-catenin signaling pathway.

    Shan BE, Wang MX and Li RQ

    The Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, China. baoenshan@yahoo.com.cn

    Aim: The Wnt signaling pathway plays a pivotal role in cellular developmental processes and human carcinogenesis. The aim of this study was to investigate the effects of quercetin on the growth of the colon carcinoma cell line and the regulation effect of quercetin on the Wnt/beta-catenin signaling pathway.

    Methods: MTT assay was used to determine the reduction of cell viability of quercetin on SW480 cells and clone 26 cells. The apoptotic rate and cell-cycle analysis after treatment with quercetin was determined by flow cytometry. Effects of quercetin on mRNA expression of cyclin D(1) and survivin were detected by semiquantitative RT-PCR. After treatment with quercetin, the protein expression of cyclin D(1) and survivin in SW480 cells was analyzed by Western blot analysis. We built a Wnt/beta-catenin signaling pathway reporter gene model. The regulation effect of quercetin on the Wnt/beta-catenin signaling transcription was investigated by using this reporter gene model.

    Results: Quercetin reduced cell viability in a dose- and time-dependent manner in SW480 and clone 26 cells. The percentages of SW480 cells and clone 26 cells at G(2)/M phase were increased significantly after treatment with 40 approximately 80 micromol/L quercetin for 48 hours. Quercetin induced the apoptosis of SW480 cells in a dose-dependent manner at the concentration of 20, 40, 60, anf 80 micromol/L. However, quercetin only induced the apoptosis of clone 26 cells at the concentration of 80 micromol/L. Quercetin downregulated transcriptional activity of beta-catenin/Tcf in SW480 cells transiently transfected with the TCF-4 reporter gene. Within 24 hours of treatment, a 160-mumol/L concentration of quercetin reduced beta-catenin/Tcf transcriptional activity by about 18-fold. Cyclin D(1) and the survivin gene were downregulated markedly by quercetin in a dose-dependent manner at both the transcription and protein expression levels.

    Conclusion: The results indicate that the molecular mechanism underlying the antitumor effect of quercetin in SW480 colon cancer cells is related to the inhibition of expression of cyclin D(1) and survivin as well as the Wnt/beta-catenin signaling pathway. Therefore, the Wnt/beta-catenin signaling pathway could be qualified as one of the promising targets for innovative treatment strategies of colorectal cancer.

    Cancer investigation 2009;27;6;604-12

  • Target gene activation of the Wnt signaling pathway in nuclear beta-catenin accumulating cells of adamantinomatous craniopharyngiomas.

    Hölsken A, Kreutzer J, Hofmann BM, Hans V, Oppel F, Buchfelder M, Fahlbusch R, Blümcke I and Buslei R

    Departments of Neuropathology Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany.

    Activating beta-catenin (CTNNB1) mutations can be identified in the majority of adamantinomatous craniopharyngiomas (adaCP), suggesting an aberrant Wnt signaling pathway in this histopathologically peculiar tumor entity. However, there is no proven evidence that nuclear translocation of beta-catenin is associated with CTNNB1 mutations and target gene activation. We performed a laser-microdissection-based study comparing beta-catenin accumulating vs. non-accumulating tumor cells. Mutational analysis and gene expression profiling using real-time polymerase chain reaction were conducted in adamantinomatous and papillary tumor specimens. Target gene activation, that is, over-expression of Axin2 could be detected in adaCP, especially in tumor cells with nuclear beta-catenin accumulation. In addition, increased expression of BMP4 was identified in the accumulating cell population, which supports the hypothesis of an oral ectodermal origin. Interestingly, accumulating and non-accumulating tumor cell populations carried CTNNB1 mutations within exon 3. We extended the analysis, therefore, towards genetic regions encoding for membrane linkage and active/passive nuclear transport mechanisms (exon 4 and exon 8-13), but could not detect any alteration. This is the first report demonstrating an association between nuclear beta-catenin accumulation and target gene activation in adaCP. The results confirm the Wnt signaling pathway as molecular basis of the distinct and challenging clinical and morphological phenotype of adaCP.

    Brain pathology (Zurich, Switzerland) 2009;19;3;357-64

  • Positive reciprocal regulation of ubiquitin C-terminal hydrolase L1 and beta-catenin/TCF signaling.

    Bheda A, Yue W, Gullapalli A, Whitehurst C, Liu R, Pagano JS and Shackelford J

    Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.

    Deubiquitinating enzymes (DUBs) are involved in the regulation of distinct critical cellular processes. Ubiquitin C-terminal Hydrolase L1 (UCH L1) has been linked to several neurological diseases as well as human cancer, but the physiological targets and the regulation of UCH L1 expression in vivo have been largely unexplored. Here we demonstrate that UCH L1 up-regulates beta-catenin/TCF signaling: UCH L1 forms endogenous complexes with beta-catenin, stabilizes it and up-regulates beta-catenin/TCF-dependent transcription. We also show that, reciprocally, beta-catenin/TCF signaling up-regulates expression of endogenous UCH L1 mRNA and protein. Moreover, using ChIP assay and direct mutagenesis we identify two TCF4-binding sites on the uch l1 promoter that are involved in this regulation. Since the expression and deubiquitinating activity of UCH L1 are required for its own basic promoter activity, we propose that UCH L1 up-regulates its expression by activation of the oncogenic beta-catenin/TCF signaling in transformed cells.

    Funded by: NCI NIH HHS: 2-P01-CA19014-26, P01 CA019014, T32 CA009156; NIAID NIH HHS: R03 AI085545

    PloS one 2009;4;6;e5955

  • The Wnt receptor FZD1 mediates chemoresistance in neuroblastoma through activation of the Wnt/beta-catenin pathway.

    Flahaut M, Meier R, Coulon A, Nardou KA, Niggli FK, Martinet D, Beckmann JS, Joseph JM, Mühlethaler-Mottet A and Gross N

    Department of Paediatrics, University Hospital CHUV, Lausanne, Switzerland. Marjorie.Flahaut@chuv.ch

    The development of chemoresistance represents a major obstacle in the successful treatment of cancers such as neuroblastoma (NB), a particularly aggressive childhood solid tumour. The mechanisms underlying the chemoresistant phenotype in NB were addressed by gene expression profiling of two doxorubicin (DoxR)-resistant vs sensitive parental cell lines. Not surprisingly, the MDR1 gene was included in the identified upregulated genes, although the highest overexpressed transcript in both cell lines was the frizzled-1 Wnt receptor (FZD1) gene, an essential component of the Wnt/beta-catenin pathway. FZD1 upregulation in resistant variants was shown to mediate sustained activation of the Wnt/beta-catenin pathway as revealed by nuclear beta-catenin translocation and target genes transactivation. Interestingly, specific micro-adapted short hairpin RNA (shRNAmir)-mediated FZD1 silencing induced parallel strong decrease in the expression of MDR1, another beta-catenin target gene, revealing a complex, Wnt/beta-catenin-mediated implication of FZD1 in chemoresistance. The significant restoration of drug sensitivity in FZD1-silenced cells confirmed the FZD1-associated chemoresistance. RNA samples from 21 patient tumours (diagnosis and postchemotherapy), showed a highly significant FZD1 and/or MDR1 overexpression after treatment, underlining a role for FZD1-mediated Wnt/beta-catenin pathway in clinical chemoresistance. Our data represent the first implication of the Wnt/beta-catenin pathway in NB chemoresistance and identify potential new targets to treat aggressive and resistant NB.

    Oncogene 2009;28;23;2245-56

  • Regulation of mammary stem/progenitor cells by PTEN/Akt/beta-catenin signaling.

    Korkaya H, Paulson A, Charafe-Jauffret E, Ginestier C, Brown M, Dutcher J, Clouthier SG and Wicha MS

    Comprehensive Cancer Center, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA. hkorkaya@med.umich.edu

    Recent evidence suggests that many malignancies, including breast cancer, are driven by a cellular subcomponent that displays stem cell-like properties. The protein phosphatase and tensin homolog (PTEN) is inactivated in a wide range of human cancers, an alteration that is associated with a poor prognosis. Because PTEN has been reported to play a role in the maintenance of embryonic and tissue-specific stem cells, we investigated the role of the PTEN/Akt pathway in the regulation of normal and malignant mammary stem/progenitor cell populations. We demonstrate that activation of this pathway, via PTEN knockdown, enriches for normal and malignant human mammary stem/progenitor cells in vitro and in vivo. Knockdown of PTEN in normal human mammary epithelial cells enriches for the stem/progenitor cell compartment, generating atypical hyperplastic lesions in humanized NOD/SCID mice. Akt-driven stem/progenitor cell enrichment is mediated by activation of the Wnt/beta-catenin pathway through the phosphorylation of GSK3-beta. In contrast to chemotherapy, the Akt inhibitor perifosine is able to target the tumorigenic cell population in breast tumor xenografts. These studies demonstrate an important role for the PTEN/PI3-K/Akt/beta-catenin pathway in the regulation of normal and malignant stem/progenitor cell populations and suggest that agents that inhibit this pathway are able to effectively target tumorigenic breast cancer cells.

    Funded by: NCI NIH HHS: 5 P30 CA46592, CA101860, CA129765, R01 CA101860, R01 CA129765

    PLoS biology 2009;7;6;e1000121

  • Blocking beta-catenin binding to the ZBP1 promoter represses ZBP1 expression, leading to increased proliferation and migration of metastatic breast-cancer cells.

    Gu W, Pan F and Singer RH

    Department of Anatomy and Structural Biology, Albert Einstein College of Medicine 1300 Morris Park Avenue, Bronx, NY 10461, USA. wgu@aecom.yu.edu

    ZBP1 (zipcode-binding protein 1, also known as IMP-1) is an mRNA regulator, functioning in mRNA localization, stability and translational control. ZBP1 is actively expressed during embryogenesis and tumorigenesis, but its expression is repressed in metastatic breast-cancer cell lines and tumors. In this article, we show that downregulation of ZBP1 expression results from its promoter methylation, an epigenetic process that remodels the chromatin structure and frequently represses gene activity. Demethylation of the ZBP1 promoter in metastatic cells reactivated ZBP1 expression, owing to restoration of the interaction of the ZBP1 promoter with beta-catenin. Loss of ZBP1 function not only increased growth ability of metastatic cells, but also promoted cell migration. We identified a number of mRNAs that were selectively associated with ZBP1 in breast-cancer cells. Many of these are involved in cell motility and in cell-cycle regulation, and displayed altered expression patterns in the absence of ZBP1. These data suggest that repression of ZBP1 deregulates its associated mRNAs, leading to the phenotypic changes of breast cancers.

    Funded by: NCI NIH HHS: CA83208; NIAMS NIH HHS: AR41480; NIGMS NIH HHS: R01 GM084364-15A1

    Journal of cell science 2009;122;Pt 11;1895-905

  • Up-regulation of C-terminal tensin-like molecule promotes the tumorigenicity of colon cancer through beta-catenin.

    Liao YC, Chen NT, Shih YP, Dong Y and Lo SH

    Center for Tissue Regeneration and Repair, Department of Biochemistry and Molecular Medicine, University of California-Davis, Sacramento, California 95817, USA.

    C-terminal tensin-like (cten) is a focal adhesion molecule belonging to the tensin family. Previous studies have suggested that cten may function as a prostate-specific tumor suppressor. Here, we show that although cten is expressed at a very low level in normal colon, its expression is significantly up-regulated in colon cancer. Furthermore, a high population of cten is found in the nucleus, where it interacts with beta-catenin, a critical player in the canonical Wnt pathway. This interaction may contribute to the role of cten in enhancing the colony formation, anchorage-independent growth, and invasiveness of colon cancer cells. Our studies have identified cten as a novel nuclear partner of beta-catenin, showed an oncogenic activity of cten in colon cancers, and revealed cten as a potential biomarker and target for colon cancers.

    Funded by: NCI NIH HHS: CA102537, R01 CA102537-05

    Cancer research 2009;69;11;4563-6

  • Aberrant activation of hedgehog signaling pathway contributes to endometrial carcinogenesis through beta-catenin.

    Liao X, Siu MK, Au CW, Chan QK, Chan HY, Wong ES, Ip PP, Ngan HY and Cheung AN

    Department of Pathology, Queen Mary Hospital, the University of Hong Kong, Hong Kong, China.

    The hedgehog and Wnt signaling pathways play important roles in human cancers with possible interaction. This study aimed at analysis and correlation of the expression of Gli1, a transcriptional factor and target gene of hedgehog signaling pathway, with clinicopathological parameters and expression of beta-catenin, an important member of the Wnt pathway, in normal, hyperplastic and malignant endometrium. Immunohistochemical study on 15 normal endometrium, 14 simple and complex hyperplasia without atypia, 37 atypical complex hyperplasia and 80 endometrial cancers showed significant Gli1 overexpression and beta-catenin nuclear immunoreactivity in endometrial cancers and atypical endometrial hyperplasia when compared with normal endometrium (P<0.05). Overexpression of Gli1 in endometrial cancers correlated with well-differentiated histological grade (P<0.001), non-myometrial invasion (P=0.004) and superficial myometrial invasion (P=0.041). beta-Catenin nuclear immunoreactivity was also associated with well-differentiated histology (P=0.013). Gli1 overexpression positively correlated with beta-catenin nuclear immunoreactivity in atypical complex hyperplasia (P=0.013) and endometrial carcinoma (P=0.017). Similar Gli1 and beta-catenin protein expression pattern was observed in normal and endometrial cancer cell lines by western blotting. We further showed a complex formation between Gli1 and beta-catenin protein in endometrial cancer cell lines in an immunoprecipitation study. Ectopic overexpression of Gli1 into endometrial cancer cells led to reduced expression of beta-catenin in cell cytoplasm and increased expression of beta-catenin in the nuclei. In summary, overexpression of Gli1 was an early event in endometrial carcinogenesis. Aberrant activation of hedgehog pathway may play important roles in endometrial cancer through beta-catenin nuclear accumulation.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2009;22;6;839-47

  • [Correlation of genetic polymorphisms of beta-catenin to hepatitis B virus-related hepatocellular carcinoma].

    Lai J, Gao ZL, Yang L, Chen W, Zhou X and Ke WM

    Department of Infection Diseases, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510630, P.R. China.

    Wnt signaling pathway plays an important role in the carcinogenesis of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). beta-catenin protein is a pivotal regulator in the pathway. Genetic mutation has been observed in the codons 32-45 at exon 3 of beta-catenin gene in HCC tissues. This study was to investigate the correlation of genetic polymorphisms of beta-catenin to HBV-related HCC.

    Methods: We conducted epidemiologic and genetic investigation in 162 patients with HBV-related HCC. According to matching requirements, patients with or without family history of HCC were paired with a ratio of 1:1. Exon 3 of beta-catenin gene was detected by polymerase chain reaction (PCR) and DNA sequencing. Single nucleotide polymorphism (SNP) rs28931588, rs28931589, codons 31-46 sequences and genetic investigation were analyzed.

    Results: Among the 162 HCC patients, 16 (9.88%) had family history of HCC; 12 patients with family history of HCC and 12 without family history were matched. The 24 patients all showed G on rs28931588 and rs28931589. Three patients showed mutation in codons 32-46 and had genetic polymorphisms. Definite mutational regularity or characteristic mutational site was not observed.

    Conclusion: SNP rs28931588, rs28931589 and codons 31-46 sequences may not be the genetic markers in HBV-related HCC.

    Ai zheng = Aizheng = Chinese journal of cancer 2009;28;6;607-11

  • E-cadherin, beta-catenin, and ZEB1 in malignant progression of cancer.

    Schmalhofer O, Brabletz S and Brabletz T

    Department of Visceral Surgery, University of Freiburg, Hugstetter Strasse 55, 79106, Freiburg, Germany.

    The embryonic program 'epithelial-mesenchymal transition' (EMT) is activated during tumor invasion in disseminating cancer cells. Characteristic to these cells is a loss of E-cadherin expression, which can be mediated by EMT-inducing transcriptional repressors, e.g. ZEB1. Consequences of a loss of E-cadherin are an impairment of cell-cell adhesion, which allows detachment of cells, and nuclear localization of beta-catenin. In addition to an accumulation of cancer stem cells, nuclear beta-catenin induces a gene expression pattern favoring tumor invasion, and mounting evidence indicates multiple reciprocal interactions of E-cadherin and beta-catenin with EMT-inducing transcriptional repressors to stabilize an invasive mesenchymal phenotype of epithelial tumor cells.

    Cancer metastasis reviews 2009;28;1-2;151-66

  • Expression of P-aPKC-iota, E-cadherin, and beta-catenin related to invasion and metastasis in hepatocellular carcinoma.

    Du GS, Wang JM, Lu JX, Li Q, Ma CQ, Du JT and Zou SQ

    Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.

    Objectives: Atypical protein kinase C iota (aPKC-iota) and its associated intracellular molecules, E-cadherin and beta-catenin, are important for cell polarization in tumorigenesis and progression. Expression of aPKC-iota, P-aPKC-iota (activated aPKC-iota), E-cadherin, and beta-catenin in hepatocellular carcinoma (HCC) was measured, and correlation with clinicopathological characteristics of HCC was analyzed.

    Methods: Paraffin-embedded tumor tissue was obtained from patients with HCC after resection without preoperative radiotherapy or chemotherapy. Gene expression was detected by polymerase chain reaction (PCR), and protein expression was detected by immunohistochemistry and Western blot analysis. Expressions of aPKC-iota, P-aPKC-iota, E-cadherin, and beta-catenin were analyzed with relation to the clinicopathological data.

    Results: The gene and protein expression of aPKC-iota are obviously higher in HCC tissues than that in peritumoral tissues and normal tissues by semiquantitative PCR and immunohistochemistry methods. Accumulation of aPKC-iota in HCC cytoplasm and nucleolus inhibited the later formation of belt-like adherens junctions (AJs) and/or tight junctions (TJs) in cell-cell contact. E-cadherin was reduced and accumulation of cytoplasm beta-catenin was increased in HCC. The expression of aPKC-iota was closely related to pathological differentiation, tumor size, invasion, and metastasis of HCC.

    Conclusion: Accumulation of cytoplasm aPKC-iota may reflect pathological differentiation, invasion, and metastasis potential of HCC. In this regard, our study on HCC revealed the potential usefulness of aPKC-iota, E-cadherin, and beta-catenin as a prognostic marker, closely related to pathological differentiation, invasion, metastasis, and prognosis of HCC.

    Annals of surgical oncology 2009;16;6;1578-86

  • Interaction between HSP60 and beta-catenin promotes metastasis.

    Tsai YP, Yang MH, Huang CH, Chang SY, Chen PM, Liu CJ, Teng SC and Wu KJ

    Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.

    Heat shock protein 60 (HSP60) plays an essential role in assisting many newly synthesized proteins to reach their native forms. Increased HSP60 expression is observed in different types of human cancers with metastasis (e.g. pancreatic cancer and large bowel carcinoma). However, the role of HSP60 in metastasis remains little known. Aberrant activation of beta-catenin plays a key role in tumorigenesis and metastasis. Here, we show that overexpression of HSP60 induces metastatic phenotypes in vitro and in vivo. HSP60 interacts with beta-catenin, increases beta-catenin protein levels through the apical domain and enhances its transcriptional activity. Short-interference RNA-mediated repression of beta-catenin reverts metastatic activity caused by HSP60 overexpression. Proteosomal activity is not required for the induction of beta-catenin by HSP60. Coexpression of HSP60 and nuclear beta-catenin predicts a worse prognosis of metastatic head and neck cancer patients. These results implicate a novel role of HSP60 in metastasis.

    Carcinogenesis 2009;30;6;1049-57

  • Overexpression of beta-catenin is responsible for the development of portal hypertension during liver cirrhosis.

    Hong JJ, Pan FY, Qian Y, Cheng LC, Zhang HX, Xue B and Li CJ

    The Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.

    beta-catenin functions as both a structural protein and a transcriptional activator. In this study, we examined the expression of beta-catenin in human cirrhotic livers, and administered adenoviruses carrying the beta-catenin or DeltaTCF4 genes to cirrhotic rats to investigate the role of beta-catenin in the development of liver cirrhosis development. beta-catenin expression was associated with liver cirrhosis development in cirrhotic human and rat liver. beta-catenin adenovirus was capable of accelerating cirrhosis progress but this progression was unaffected by administration of DeltaTCF4 adenovirus. beta-catenin was mainly located in the intercellular regions between liver cells and was highly concentrated in the hepatic sinusoid wall, where alpha-smooth muscle actin (SMA) was also mainly distributed. The binding of beta-catenin to alpha-SMA was also increased in cirrhotic liver. Portal vein blood pressure was significantly increased in the group administered beta-catenin adenovirus, but not in that receiving DeltaTCF4 adenovirus. These results suggest that high concentrations of beta-catenin at the hepatic intercellular membrane and the hepatic sinusoid wall contribute to hepatic hyperpiesia in liver cirrhosis patients. beta-catenin functions as a structural molecule, but not as a signaling molecule, during liver cirrhosis development.

    Anatomical record (Hoboken, N.J. : 2007) 2009;292;6;818-26

  • Requirement of the Akt/beta-catenin pathway for uterine carcinosarcoma genesis, modulating E-cadherin expression through the transactivation of slug.

    Saegusa M, Hashimura M, Kuwata T and Okayasu I

    Department of Pathology, Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan. msaegusa@med.kitasato-u.ac.jp

    Uterine carcinosarcomas (UCSs) are considered to represent true examples of the epithelial-mesenchymal transition. Akt plays a key role in the induction of epithelial-mesenchymal transition, but little is known about its involvement in tumorigenesis. Here we examined the functional roles of the Akt/beta-catenin pathway in UCSs. In clinical samples, phospho-Akt (pAkt) expression was found to be significantly increased in mesenchymal compared with epithelial components, exhibiting both positive and negative correlations with nuclear beta-catenin and E-cadherin, respectively. Expression levels of the transcription factor Slug were also significantly up-regulated in the mesenchymal components and strongly correlated with both pAkt and nuclear beta-catenin. In endometrial cancer cell lines, active Akt induced the stabilization of nuclear beta-catenin through the phosphorylation of GSK-3beta, and this, in turn, led to the transactivation of Slug, which was mediated by nuclear beta-catenin. Moreover, Slug overexpression itself caused repression of E-cadherin, with subtle changes in cell morphology. In addition, knockdown of the retinoblastoma gene product (Rb) up-regulated pAkt and repressed E-cadherin, consistent with the in vivo finding of significantly decreased Rb expression in mesenchymal components. These findings suggest that changes in the Akt/beta-catenin pathway, as well as alterations in Rb expression, may be essential for both the establishment and maintenance of phenotypic characteristics of UCSs, playing key roles in the regulation of E-cadherin through the transactivation of the Slug gene.

    The American journal of pathology 2009;174;6;2107-15

  • NKX2-5 regulates the expression of beta-catenin and GATA4 in ventricular myocytes.

    Riazi AM, Takeuchi JK, Hornberger LK, Zaidi SH, Amini F, Coles J, Bruneau BG and Van Arsdell GS

    Labatt Family Heart Centre, Hospital for Sick Children, Toronto, Ontario, Canada. ali.riazi@sickkids.ca

    Background: The molecular pathway that controls cardiogenesis is temporally and spatially regulated by master transcriptional regulators such as NKX2-5, Isl1, MEF2C, GATA4, and beta-catenin. The interplay between these factors and their downstream targets are not completely understood. Here, we studied regulation of beta-catenin and GATA4 by NKX2-5 in human fetal cardiac myocytes.

    Using antisense inhibition we disrupted the expression of NKX2-5 and studied changes in expression of cardiac-associated genes. Down-regulation of NKX2-5 resulted in increased beta-catenin while GATA4 was decreased. We demonstrated that this regulation was conferred by binding of NKX2-5 to specific elements (NKEs) in the promoter region of the beta-catenin and GATA4 genes. Using promoter-luciferase reporter assay combined with mutational analysis of the NKEs we demonstrated that the identified NKX2-5 binding sites were essential for the suppression of beta-catenin, and upregulation of GATA4 by NKX2-5.

    Conclusions: This study suggests that NKX2-5 modulates the beta-catenin and GATA4 transcriptional activities in developing human cardiac myocytes.

    PloS one 2009;4;5;e5698

  • Activation of Wnt/beta-catenin signalling pathway induces chemoresistance to interferon-alpha/5-fluorouracil combination therapy for hepatocellular carcinoma.

    Noda T, Nagano H, Takemasa I, Yoshioka S, Murakami M, Wada H, Kobayashi S, Marubashi S, Takeda Y, Dono K, Umeshita K, Matsuura N, Matsubara K, Doki Y, Mori M and Monden M

    Department of Surgery, Graduate School of Medicine and Health Science, Osaka University, Osaka, Japan.

    Type I IFN receptor type 2 (IFNAR2) expression correlates significantly with clinical response to interferon (IFN)-alpha/5-fluorouracil (5-FU) combination therapy for hepatocellular carcinoma (HCC). However, some IFNAR2-positive patients show no response to the therapy. This result suggests the possibility of other factors, which would be responsible for resistance to IFN-alpha/5-FU therapy. The aim of this study was to examine the mechanism of anti-proliferative effects of IFN-alpha/5-FU therapy and search for a biological marker of chemoresistance to such therapy. Gene expression profiling and molecular network analysis were used in the analysis of non-responders and responders with IFNAR2-positive HCC. The Wnt/beta-catenin signalling pathway contributed to resistance to IFN-alpha/5-FU therapy. Immunohistochemical analysis showed positive epithelial cell adhesion molecule (Ep-CAM) expression, the target molecule of Wnt/beta-catenin signalling, only in non-responders. In vitro studies showed that activation of Wnt/beta-catenin signalling by glycogen synthesis kinase-3 inhibitor (6-bromoindirubin-3'-oxime (BIO)) induced chemoresistance to IFN-alpha/5-FU. BrdU-based cell proliferation ELISA and cell cycle analysis showed that concurrent addition of BIO and IFN-alpha/5-FU significantly to hepatoma cell cultures reduced the inhibitory effects of the latter two on DNA synthesis and accumulation of cells in the S-phase. The results indicate that activation of Wnt/beta-catenin signalling pathway induces chemoresistance to IFN-alpha/5-FU therapy and suggest that Ep-CAM is a potentially useful marker for resistance to such therapy, especially in IFNAR2-positive cases.

    British journal of cancer 2009;100;10;1647-58

  • The intratumoral distribution of nuclear beta-catenin is a prognostic marker in colon cancer.

    Horst D, Reu S, Kriegl L, Engel J, Kirchner T and Jung A

    Pathologisches Institut der Ludwig-Maximilians-Universität, Munich, Germany. david.horst@med.uni-muenchen.de

    Background: Most colon cancers harbor mutations of APC or beta-catenin, both of which may lead to nuclear beta-catenin accumulation in the tumor cells and constitutively activated expression of its target genes. In many colon cancers, however, nuclear beta-catenin accumulation is heterogeneous throughout the tumor and often confined to the tumor margin. Herein, the authors investigated whether the intratumoral distribution of nuclear beta-catenin can serve as a prognostic marker for survival and tumor progression of stage IIA colon cancer patients.

    Methods: In total, 142 patients with primarily resected, moderately differentiated stage IIA colon cancer were included in this study. The patterning of nuclear beta-catenin expression was evaluated on immunohistochemically stained whole tissue sections of the tumors and was correlated with cancer-specific survival and disease-free survival using univariate and multivariate statistical analyses.

    Results: Four distinct patterns of nuclear beta-catenin expression were identified, and 2 main categories comprising tumors with or without intratumoral regulation of nuclear beta-catenin were distinguished. Moreover, the results demonstrated that the patterning, and especially the regulation or absence of regulation of nuclear beta-catenin expression, was a strong predictive marker of patient survival and tumor progression.

    Conclusions: The current results indicated that the distribution of nuclear beta-catenin expression can be used as a good prognostic marker in patients with stage IIA colon cancer. Thus, the evaluation of nuclear beta-catenin may help to identify patients who will have a shorter than average survival and patients with a greater risk of disease progression who may be considered for adjuvant therapeutic modalities and intensified clinical aftercare in the future.

    Cancer 2009;115;10;2063-70

  • TCF/beta-catenin plays an important role in HCCR-1 oncogene expression.

    Cho GW, Kim MH, Kim SH, Ha SA, Kim HK, Kim S and Kim JW

    Department of Neurology, College of Medicine, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul, 133-791, Korea. gwcho7@hanyang.ac.kr

    Background: Oncogene HCCR-1 functions as a negative regulator of the p53 and contributes to tumorigenesis of various human tissues. However, it is unknown how HCCR-1 contributes to the cellular and biochemical mechanisms of human tumorigenesis.

    Results: In this study, we showed how the expression of HCCR-1 is modulated. The luciferase activity assay indicated that the HCCR-1 5'-flanking region at positions -166 to +30 plays an important role in HCCR-1 promoter activity. Computational analysis of this region identified two consensus sequences for the T-cell factor (TCF) located at -26 to -4 (Tcf1) and -136 to -114 (Tcf2). Mutation at the Tcf1 site led to a dramatic decrease in promoter activity. Mobility shift assays (EMSA) revealed that nuclear proteins bind to the Tcf1 site, but not to the Tcf2 site. LiCl, Wnt signal activator by GSK-3beta inhibition, significantly increased reporter activities in wild-type Tcf1-containing constructs, but were without effect in mutant Tcf1-containing constructs in HEK/293 cells. In addition, endogenous HCCR-1 expression was also increased by treatment with GSK-3beta inhibitor, LiCl or AR-A014418 in HEK/293 and K562 cells. Finally, we also observed that the transcription factor, TCF, and its cofactor, beta-catenin, bound to the Tcf1 site.

    Conclusion: These findings suggest that the Tcf1 site on the HCCR-1 promoter is a major element regulating HCCR-1 expression and abnormal stimulation of this site may induce various human cancers.

    BMC molecular biology 2009;10;42

  • Beta-catenin mediates soft tissue contracture in clubfoot.

    Poon R, Li C and Alman BA

    Division of Orthopaedic Surgery, Program in Developmental and Stem Cell Biology, Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G1X8, Canada.

    The contracted tissues from clubfeet resemble tissues from other fibroproliferative disorders such as palmar fibromatosis. Beta-catenin-mediated signaling is a crucial pathway controlling the fibroproliferative response in many fibroproliferative disorders. To determine if beta-catenin signaling plays a role in clubfoot, contracted and less contracted tissues from clubfeet were studied using Western analysis to determine the protein level of beta-catenin. Primary cell cultures were established from these tissues, and they were treated with either lithium to increase beta-catenin or Dickkopf-1 to inhibit beta-catenin. RNA was extracted from the cells and analyzed to determine how beta-catenin regulates expression of Type III collagen, an extracellular matrix protein upregulated in contracted clubfoot tissue. There was a more than twofold increase in beta-catenin protein in the contracted tissues. Treatment with either lithium or Dickkopf-1 showed Type III collagen RNA expression positively correlated with the protein level of beta-catenin. These data support the concept that beta-catenin-mediated signaling plays an important role regulating contracture in clubfeet. Because pharmacologic agents are under development to block this signaling pathway, such drugs could be used in cases of severe stiffness to improve range of motion or to decrease the need for radical surgical approaches.

    Clinical orthopaedics and related research 2009;467;5;1180-5

  • Beta-catenin status in paediatric medulloblastomas: correlation of immunohistochemical expression with mutational status, genetic profiles, and clinical characteristics.

    Fattet S, Haberler C, Legoix P, Varlet P, Lellouch-Tubiana A, Lair S, Manie E, Raquin MA, Bours D, Carpentier S, Barillot E, Grill J, Doz F, Puget S, Janoueix-Lerosey I and Delattre O

    INSERM U830, Laboratoire de Génétique et Biologie des Cancers, 75248 Paris Cedex 05, France.

    Medulloblastoma is the most frequent malignant paediatric brain tumour. The activation of the Wnt/beta-catenin pathway occurs in 10-15% of medulloblastomas and has been recently described as a marker for favourable patient outcome. We report a series of 72 paediatric medulloblastomas evaluated for beta-catenin protein expression, CTNNB1 mutations, and comparative genomic hybridization. Gene expression profiles were also available in a subset of 40 cases. Immunostaining of beta-catenin showed extensive nuclear staining (>50% of the tumour cells) in six cases and focal nuclear staining (<10% of cells) in three cases. The other cases either exhibited a signal strictly limited to the cytoplasm (58 cases) or were negative (five cases). CTNNB1 mutations were detected in all beta-catenin extensively nucleopositive cases. The expression profiles of these cases documented strong activation of the Wnt/beta-catenin pathway. Remarkably, five out of these six tumours showed a complete loss of chromosome 6. In contrast, cases with focal nuclear beta-catenin staining, as well as tumours with negative or cytoplasmic staining, never demonstrated CTNNB1 mutation, Wnt/beta-catenin pathway activation or chromosome 6 loss. Patients with extensive nuclear staining were significantly older at diagnosis and were in continuous complete remission after a mean follow-up of 75.7 months (range 27.5-121.2 months) from diagnosis. All three patients with focal nuclear staining of beta-catenin died within 36 months from diagnosis. Altogether, these data confirm and extend previous observations that CTNNB1-mutated tumours represent a distinct molecular subgroup of medulloblastomas with favourable outcome, indicating that therapy de-escalation should be considered. International consensus on the definition criteria of this distinct medulloblastoma subgroup should be achieved.

    The Journal of pathology 2009;218;1;86-94

  • Elevated expression of DKK1 is associated with cytoplasmic/nuclear beta-catenin accumulation and poor prognosis in hepatocellular carcinomas.

    Yu B, Yang X, Xu Y, Yao G, Shu H, Lin B, Hood L, Wang H, Yang S, Gu J, Fan J and Qin W

    Shanghai Medical College, Fudan University, Shanghai, China.

    To assess the value of Dickkopf-1 (DKK1) for predicting clinical outcome of human hepatocellular carcinoma (HCC) in patients with HCC.

    Methods: Expression of DKK1 and beta-catenin was investigated in HCC cell lines using qRT-PCR, Western blotting and immunofluorescence. Tissue microarrays representing 314 HCC patients were used to determine the expression patterns of DKK1 and beta-catenin by immunohistochemistry, and prognostic significance was assessed by using Kaplan-Meier survival estimates and log-rank tests.

    Results: The expression level of DKK1 was associated with the staining pattern of beta-catenin in HCC cell lines, and DKK1 overexpression correlated with beta-catenin cytoplasmic/nuclear accumulation in clinical HCC samples (P=0.011, correlation coefficient=0.144). High DKK1 expression predicted unfavorable prognosis in HCC patients, especially in early stage patients and those with normal AFP levels. In multivariate analyses, DKK1 was an independent predictor for overall survival (OS) (P=0.002) and disease-free survival (DFS) (P=0.002) of HCC patients. Furthermore, the HCC patients with high DKK1 expression and cytoplasmic/nuclear beta-catenin accumulation had very poor prognosis.

    Conclusions: Elevated expression of DKK1 is a critical event in patients with HCC that indicates poor clinical outcome. DKK1, alone or combined with beta-catenin, is a novel prognostic predictor for HCC patients.

    Journal of hepatology 2009;50;5;948-57

  • Enhanced interaction between focal adhesion and adherens junction proteins: involvement in sphingosine 1-phosphate-induced endothelial barrier enhancement.

    Sun X, Shikata Y, Wang L, Ohmori K, Watanabe N, Wada J, Shikata K, Birukov KG, Makino H, Jacobson JR, Dudek SM and Garcia JG

    Department of Medicine, Division of Biological Sciences, The University of Chicago, 5841 Maryland Ave., Chicago, IL 60637-1470, USA.

    Sphingosine 1-phosphate (S1P) is an important vascular barrier regulatory agonist which enhances the junctional integrity of human lung endothelial cell monolayers. We have now demonstrated that S1P induced cortical actin ring formation and redistribution of focal adhesion kinase (FAK) and paxillin to the cell periphery suggesting the critical role of cell-cell adhesion in endothelial barrier enhancement. Co-immunoprecipitation studies revealed increased association of VE-cadherin with FAK and paxillin in S1P-challenged human pulmonary artery endothelial cell (HPAEC) monolayers. Furthermore, S1P-induced enhancement of VE-cadherin interaction with alpha-catenin and beta-catenin was associated with the increased formation of FAK-beta-catenin protein complexes. Depletion of beta-catenin (siRNA) resulted in loss of S1P-mediated VE-cadherin association with FAK and paxillin rearrangement. Furthermore, transendothelial electrical resistance (an index of barrier function) demonstrated that beta-catenin siRNA significantly attenuated S1P-induced barrier enhancement. These results demonstrate a mechanism of S1P-induced endothelial barrier enhancement via beta-catenin-linked adherens junction and focal adhesion interaction.

    Funded by: NHLBI NIH HHS: HL075349, HL076259, HL077134, HL088144, HL58064, K08 HL077134, P01 HL058064, R01 HL075349, R01 HL076259, R01 HL088144, R56 HL088144; NIGMS NIH HHS: GM07019, T32 GM007019, T32 GM007019-32

    Microvascular research 2009;77;3;304-13

  • Epstein-Barr virus-encoded latent membrane protein 1 activates beta-catenin signaling in B lymphocytes.

    Tomita M, Dewan MZ, Yamamoto N, Kikuchi A and Mori N

    Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.

    The Epstein-Barr virus-encoded latent membrane protein 1 is considered the Epstein-Barr virus oncogene based on its importance in Epstein-Barr virus-induced B-lymphocyte transformation. Beta-catenin is a potential oncogene, and its accumulation has been implicated in a variety of human cancers. Here, we found that beta-catenin protein was highly expressed in Epstein-Barr virus-immortalized B-cell lines compared with peripheral blood mononuclear cells from healthy donors. Beta-catenin expression in Epstein-Barr virus-immortalized B-cell line decreased following treatment with LY294002, an inhibitor of phosphatidylinositol 3-kinase. Treatment with LY294002 or knockdown of beta-catenin by small interfering RNA reduced the growth of Epstein-Barr virus-immortalized B-cell line. Transient transfection of latent membrane protein 1 expression plasmid increased beta-catenin protein expression and beta-catenin-dependent transcription. Latent membrane protein 1 deletions mutants lacking the carboxyl-terminal activating region 1 domain failed to enhance beta-catenin protein expression and beta-catenin-dependent transcriptional activity. They also failed to increase phosphorylated AKT expression. Dominant-negative AKT suppressed latent membrane protein 1-induced beta-catenin-dependent transcriptional activity. These results suggest that latent membrane protein 1 activates beta-catenin through the phosphatidylinositol 3-kinase/AKT signaling pathway. Activation of the beta-catenin pathway by Epstein-Barr virus may contribute to the lymphoproliferation characteristic of Epstein-Barr virus-infected B-cells.

    Cancer science 2009;100;5;807-12

  • Mutational analysis of WTX gene in Wnt/ beta-catenin pathway in gastric, colorectal, and hepatocellular carcinomas.

    Yoo NJ, Kim S and Lee SH

    Department of Pathology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, Korea.

    A recent study of Wilms' tumors discovered a new X chromosome gene, Wilms' tumor gene on the X chromosome (WTX), which was found to harbor small deletions and point mutations. WTX protein negatively regulates Wnt/ beta-catenin signaling, and is considered a tumor-suppressor gene. One of the questions about the WTX gene is whether the genetic alterations of the WTX gene are specific to only Wilms' tumors. To see whether somatic point mutations of WTX occur in other malignancies, we analyzed the WTX gene for the detection of mutations in 141 cancer tissues by a single-strand conformation polymorphism assay. The cancer tissues consisted of 47 gastric adenocarcinomas, 47 colorectal adenocarcinomas, and 47 hepatocellular carcinomas. Overall, we detected one WTX mutation in the colorectal carcinomas (1/47; 2.1%), but there was no WTX mutation in other cancers analyzed. The detected mutation was a missense mutation (c. 1117G > A (p.Ala373Thr)). Although the WTX mutation is common in Wilms' tumors, our data indicate that it is rare in colorectal, gastric, and hepatocellular carcinomas. The data also suggest that deregulation of Wnt/ beta-catenin signaling by WTX gene mutation may be a rare event in the pathogenesis of colorectal, gastric, and hepatocellular carcinomas.

    Digestive diseases and sciences 2009;54;5;1011-4

  • Mutations in exon 3 of the CTNNB1 gene (beta-catenin gene) in cutaneous adnexal tumors.

    Kazakov DV, Sima R, Vanecek T, Kutzner H, Palmedo G, Kacerovska D, Grossmann P and Michal M

    Sikl's Department of Pathology, Charles University Medical Faculty Hospital, Pilsen, Czech Republic. kazakov@medima.cz

    Previous studies suggested that mutant beta-catenin gene cells in cutaneous adnexal tumors with matrical differentiation contribute to their tumorigenesis. Except for pilomatricoma and pilomatrical carcinoma, only a handful of other cutaneous adnexal tumor types have been studied. DNA was extracted from 86 lesions including 17 proliferating tricholemmal and trichilemmal tumors, 15 trichoblastomas, 7 trichoadenomas, 4 pilomatricomas, 1 pilomatrical carcinoma, 4 basal cell carcinomas (BCCs) with shadow cells, 2 trichofolliculomas, 3 BCCs with sebaceous differentiation, 9 sebaceous adenomas, 6 sebaceomas, 14 sebaceous carcinomas (both ocular and extraocular forms), 2 gigantic horns, and 2 apocrine mixed tumors with shadow cells and subjected to polymerase chain reaction with newly designed primers encompassing glycogen synthase kinase-3beta phosphorylation sites of the CTNNB1 gene. Also, 3 craniopharyngiomas were studied. Sequenced polymerase chain reaction products for possible beta-catenin gene mutations showed a total of 8 alterations. These included 5 different point mutations, 3 of them identified in 2 different tumors: S23N (cribriform trichoblastoma), D32Y (pilomatricoma and craniopharyngioma), G34R (pilomatrical carcinoma and craniopharyngioma), S37F (2 BCCs with shadow cell differentiation), and G34V (craniopharyngioma). This study broadens the list of cutaneous adnexal tumors harboring CTNNB1 mutations and extends the listing of the mutations occurring in these neoplasms.

    The American Journal of dermatopathology 2009;31;3;248-55

  • Wnt-5a-CKI{alpha} signaling promotes {beta}-catenin/E-cadherin complex formation and intercellular adhesion in human breast epithelial cells.

    Medrek C, Landberg G, Andersson T and Leandersson K

    Cell and Experimental Pathology and Center for Molecular Pathology, Department of Laboratory Medicine, Lund University, Universitetssjukhuset-Malmö Allmänna Sjukhus, 20502 Malmö, Sweden.

    Wnt-5a is a non-transforming Wnt protein that is implicated in cell polarity, adhesion, and motility. We have previously shown that low expression of Wnt-5a is a predictor of shorter disease-free survival in human breast cancer. Here, we investigated whether beta-catenin/E-cadherin-mediated cell-cell adhesion was affected by loss of Wnt-5a in breast carcinomas, thereby promoting a metastatic behavior of the tumor. We show that Wnt-5a stimulation of human breast epithelial cells leads to an increased Ca(2+)-dependent cell-cell adhesion. Furthermore, Wnt-5a/casein kinase Ialpha (CKIalpha)-specific Ser-45 phosphorylation of beta-catenin is associated with an increased complex formation of beta-catenin/E-cadherin. Mutation of Ser-45 decreases the beta-catenin/E-cadherin association. Also, the inhibitory effect of Wnt-5a on breast epithelial cell invasion is reduced upon mutation of beta-catenin-Ser-45. The Wnt-5a-CKIalpha-induced Ser-45 phosphorylation does not lead to degradation of beta-catenin. Finally we show that human breast cancers lacking Wnt-5a protein have a significantly lower level of membrane-associated beta-catenin. Down-regulation of Wnt-5a expression and subsequent reduction of membrane-associated beta-catenin in invasive breast cancer, can therefore contribute to a decreased cell-cell adhesion and increased motility resulting in a higher probability for metastatic disease.

    The Journal of biological chemistry 2009;284;16;10968-79

  • Genetic mutations associated with cigarette smoking in pancreatic cancer.

    Blackford A, Parmigiani G, Kensler TW, Wolfgang C, Jones S, Zhang X, Parsons DW, Lin JC, Leary RJ, Eshleman JR, Goggins M, Jaffee EM, Iacobuzio-Donahue CA, Maitra A, Klein A, Cameron JL, Olino K, Schulick R, Winter J, Vogelstein B, Velculescu VE, Kinzler KW and Hruban RH

    Department of Oncology, The Sol Goldman Pancreatic Cancer Research Center, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21231, USA.

    Cigarette smoking doubles the risk of pancreatic cancer, and smoking accounts for 20% to 25% of pancreatic cancers. The recent sequencing of the pancreatic cancer genome provides an unprecedented opportunity to identify mutational patterns associated with smoking. We previously sequenced >750 million bp DNA from 23,219 transcripts in 24 adenocarcinomas of the pancreas (discovery screen). In this previous study, the 39 genes that were mutated more than once in the discovery screen were sequenced in an additional 90 adenocarcinomas of the pancreas (validation screen). Here, we compared the somatic mutations in the cancers obtained from individuals who ever smoked cigarettes (n = 64) to the somatic mutations in the cancers obtained from individuals who never smoked cigarettes (n = 50). When adjusted for age and gender, analyses of the discovery screen revealed significantly more nonsynonymous mutations in the carcinomas obtained from ever smokers (mean, 53.1 mutations per tumor; SD, 27.9) than in the carcinomas obtained from never smokers (mean, 38.5; SD, 11.1; P = 0.04). The difference between smokers and nonsmokers was not driven by mutations in known driver genes in pancreatic cancer (KRAS, TP53, CDKN2A/p16, and SMAD4), but instead was predominantly observed in genes mutated at lower frequency. No differences were observed in mutations in carcinomas from the head versus tail of the gland. Pancreatic carcinomas from cigarette smokers harbor more mutations than do carcinomas from never smokers. The types and patterns of these mutations provide insight into the mechanisms by which cigarette smoking causes pancreatic cancer.

    Funded by: NCI NIH HHS: CA62924, P50 CA062924, P50 CA062924-08S30011, P50 CA062924-090011, P50 CA062924-160011, R01 CA039416, R37 CA043460

    Cancer research 2009;69;8;3681-8

  • Genetic associations of 115 polymorphisms with cancers of the upper aerodigestive tract across 10 European countries: the ARCAGE project.

    Canova C, Hashibe M, Simonato L, Nelis M, Metspalu A, Lagiou P, Trichopoulos D, Ahrens W, Pigeot I, Merletti F, Richiardi L, Talamini R, Barzan L, Macfarlane GJ, Macfarlane TV, Holcátová I, Bencko V, Benhamou S, Bouchardy C, Kjaerheim K, Lowry R, Agudo A, Castellsagué X, Conway DI, McKinney PA, Znaor A, McCartan BE, Healy CM, Marron M and Brennan P

    Department of Environmental Medicine and Public Health, University of Padova, Padova, Italy.

    Cancers of the upper aerodigestive tract (UADT) include malignant tumors of the oral cavity, pharynx, larynx, and esophagus and account for 6.4% of all new cancers in Europe. In the context of a multicenter case-control study conducted in 14 centers within 10 European countries and comprising 1,511 cases and 1,457 controls (ARCAGE study), 115 single nucleotide polymorphisms (SNP) from 62 a priori-selected genes were studied in relation to UADT cancer. We found 11 SNPs that were statistically associated with UADT cancers overall (5.75 expected). Considering the possibility of false-positive results, we focused on SNPs in CYP2A6, MDM2, tumor necrosis factor (TNF), and gene amplified in squamous cell carcinoma 1 (GASC1), for which low P values for trend (P trend<0.01) were observed in the main effects analyses of UADT cancer overall or by subsite. The rare variant of CYP2A6 -47A>C (rs28399433), a phase I metabolism gene, was associated with reduced UADT cancer risk (P trend=0.01). Three SNPs in the MDM2 gene, involved in cell cycle control, were associated with UADT cancer. MDM2 IVS5+1285A>G (rs3730536) showed a strong codominant effect (P trend=0.007). The rare variants of two SNPs in the TNF gene were associated with a decreased risk; for TNF IVS1+123G>A (rs1800610), the P trend was 0.007. Variants in two SNPs of GASC1 were found to be strongly associated with increased UADT cancer risk (for both, P trend=0.008). This study is the largest genetic epidemiologic study on UADT cancers in Europe. Our analysis points to potentially relevant genes in various pathways.

    Cancer research 2009;69;7;2956-65

  • Caveolin-1-mediated suppression of cyclooxygenase-2 via a beta-catenin-Tcf/Lef-dependent transcriptional mechanism reduced prostaglandin E2 production and survivin expression.

    Rodriguez DA, Tapia JC, Fernandez JG, Torres VA, Muñoz N, Galleguillos D, Leyton L and Quest AF

    Fondo de Investigación Avanzada en Areas Prioritarias, Center for Molecular Studies of the Cell, Departmento de Cirugía, Hospital Clínico, Universidad de Chile, Santiago, Chile.

    Augmented expression of cyclooxygenase-2 (COX-2) and enhanced production of prostaglandin E(2) (PGE(2)) are associated with increased tumor cell survival and malignancy. Caveolin-1 is a scaffold protein that has been proposed to function as a tumor suppressor in human cancer cells, although mechanisms underlying this ability remain controversial. Intriguingly, the possibility that caveolin-1 regulates the expression of COX-2 has not been explored. Here we show that augmented caveolin-1 expression in cells with low basal levels of this protein, such as human colon cancer (HT29, DLD-1), breast cancer (ZR75), and embryonic kidney (HEK293T) cells reduced COX-2 mRNA and protein levels and beta-catenin-Tcf/Lef and COX-2 gene reporter activity, as well as the production of PGE(2) and cell proliferation. Moreover, COX-2 overexpression or PGE(2) supplementation increased levels of the inhibitor of apoptosis protein survivin by a transcriptional mechanism, as determined by PCR analysis, survivin gene reporter assays and Western blotting. Furthermore, addition of PGE(2) to the medium prevented effects attributed to caveolin-1-mediated inhibition of beta-catenin-Tcf/Lef-dependent transcription. Finally, PGE(2) reduced the coimmunoprecipitation of caveolin-1 with beta-catenin and their colocalization at the plasma membrane. Thus, by reducing COX-2 expression, caveolin-1 interrupts a feedback amplification loop involving PGE(2)-induced signaling events linked to beta-catenin/Tcf/Lef-dependent transcription of tumor survival genes including cox-2 itself and survivin.

    Molecular biology of the cell 2009;20;8;2297-310

  • Downregulation of Wnt2 and beta-catenin by siRNA suppresses malignant glioma cell growth.

    Pu P, Zhang Z, Kang C, Jiang R, Jia Z, Wang G and Jiang H

    Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, People's Republic of China. pupeiyu33@hotmail.com

    Increasing evidence suggests that aberrant activation of Wnt signaling is involved in tumor development and progression. Our earlier study on gene expression profile in human gliomas by microarray found that some members of Wnt family were overexpressed. To further investigate the involvement of Wnt signaling in gliomas, the expression of core components of Wnt signaling cascade in 45 astrocytic glioma specimens with different tumor grades was examined by reverse transcription-PCR and immunohistochemistry. Wnt2, Wnt5a, frizzled2 and beta-catenin were overexpressed in gliomas. Knockdown of Wnt2 and its key mediator beta-catenin in the canonical Wnt pathway by siRNA in human U251 glioma cells inhibited cell proliferation and invasive ability, and induced apoptotic cell death. Furthermore, treating the nude mice carrying established subcutaneous U251 gliomas with siRNA targeting Wnt2 and beta-catenin intratumorally also delayed the tumor growth. In both in vitro and in vivo studies, downregulation of Wnt2 and beta-catenin was associated with the decrease of PI3K/p-AKT expression, indicating the interplay between Wnt/beta-catenin and PI3K/AKT signaling cascades. In conclusion, the canonical Wnt pathway is of critical importance in the gliomagenesis and intervention of this pathway may provide a new therapeutic approach for malignant gliomas.

    Cancer gene therapy 2009;16;4;351-61

  • E-cadherin, b-catenin and topoisomerase II expression in rhabdomyosarcomas.

    Gogou PN, Batistatou A, Pakos EE, Apostolikas N, Stefanou D and Tsekeris PG

    Journal of B.U.ON. : official journal of the Balkan Union of Oncology 2009;14;2;323-4

  • Expression of tight and adherens junction proteins in ulcerative colitis associated colorectal carcinoma: upregulation of claudin-1, claudin-3, claudin-4, and beta-catenin.

    Mees ST, Mennigen R, Spieker T, Rijcken E, Senninger N, Haier J and Bruewer M

    Department of General and Visceral Surgery, University Hospital of Muenster, 48149 Muenster, Germany.

    Background: Tight junction (TJ) proteins play a critical role in cellular adhesion, glandular differentiation, and cellular proliferation. The function of these proteins is compromised in a number of intestinal diseases, including ulcerative colitis that has an increased incidence for colorectal carcinoma (CAC). The aim of this study was to determine the expression of TJ proteins, claudin-1-4, occludin, ZO-1, and the adherens junction (AJ) protein beta-catenin in CAC.

    Methods: Sixteen colectomy specimens with CAC, adjoining intraepithelial neoplasia, and normal mucosa were studied by immunofluorescence. A semiquantitative evaluation of all investigated proteins was performed by scoring the staining intensity, and the TJ and AJ protein expression in neoplastic cells was compared to normal and intraepithelial neoplastic colonic mucosa.

    Results: Using an intensity scoring system, mucosa of crypts and surfaces of CAC exhibited significantly elevated expression levels of claudin-1, claudin-3, claudin-4, and beta-catenin compared to intraepithelial neoplasia and normal mucosa (p<0.05). These data were confirmed by a comparative score. The expression of claudin-2, occludin, and ZO-1 showed no differences between the groups.

    Conclusion: TJ proteins claudin-1, claudin-3, claudin-4, and the AJ protein beta-catenin are overexpressed in CAC. This suggests that these proteins may become potential markers and targets in CAC.

    International journal of colorectal disease 2009;24;4;361-8

  • Pitx2, a beta-catenin-regulated transcription factor, regulates the differentiation of outer root sheath cells cultured in vitro.

    Sohn KC, Shi G, Jang S, Choi DK, Lee Y, Yoon TJ, Park H, Hwang C, Kim HJ, Seo YJ, Lee JH, Park JK and Kim CD

    Department of Dermatology and Research Institute for Medical Sciences, School of Medicine, Chungnam National University, 55 Munhwa-ro, Daejeon 301-747, Republic of Korea.

    Background: Beta-catenin exerts its crucial role in hair follicle development and hair growth cycle. Although the importance of Wnt/beta-catenin is well recognized, the downstream effectors of beta-catenin have not been clearly elucidated yet.

    Objective: The aim of this study is to identify the beta-catenin-regulated genes in cultured human hair outer root sheath (ORS) cells.

    Methods: We transduced ORS cells with adenovirus harboring the expression cassette for constitutive active form of beta-catenin, then performed cDNA microarray.

    Results: Overexpression of beta-catenin led to the upregulation of hair cell differentiation markers such as keratin 16 and 17. In addition, the expression of Pitx2, a bicoid-type homeodomain transcription factor, was also increased by overexpression of beta-catenin in ORS cells cultured in vitro. To investigate the potential role of Pitx2, we made the recombinant adenovirus expressing Pitx2, then transduced into the cultured ORS cells. Interestingly, Pitx2 induced the expression of keratin 16 and 17, indicating that Pitx2 activates ORS cells towards the follicular differentiation pathway preferentially.

    Conclusion: Our results implicate the potential importance of Pitx2 as a beta-catenin downstream modulator in hair growth control.

    Journal of dermatological science 2009;54;1;6-11

  • Wnt signaling in Alzheimer's disease: up or down, that is the question.

    Boonen RA, van Tijn P and Zivkovic D

    Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences & University Medical Centre Utrecht, Utrecht, The Netherlands.

    Alzheimer's disease (AD) is a progressive neurodegenerative disorder, neuropathologically characterized by amyloid-beta (Abeta) plaques and hyperphosphorylated tau accumulation. AD occurs sporadically (SAD), or is caused by hereditary missense mutations in the amyloid precursor protein (APP) or presenilin-1 and -2 (PSEN1 and PSEN2) genes, leading to early-onset familial AD (FAD). Accumulating evidence points towards a role for altered Wnt/beta-catenin-dependent signaling in the etiology of both forms of AD. Presenilins are involved in modulating beta-catenin stability; therefore FAD-linked PSEN-mediated effects can deregulate the Wnt pathway. Genetic variations in the low-density lipoprotein receptor-related protein 6 and apolipoprotein E in AD have been associated with reduced Wnt signaling. In addition, tau phosphorylation is mediated by glycogen synthase kinase-3 (GSK-3), a key antagonist of the Wnt pathway. In this review, we discuss Wnt/beta-catenin signaling in both SAD and FAD, and recapitulate which of its aberrant functions may be critical for (F)AD pathogenesis. We discuss the intriguing possibility that Abeta toxicity may downregulate the Wnt/beta-catenin pathway, thereby upregulating GSK-3 and consequent tau hyperphosphorylation, linking Abeta and tangle pathology. The currently available evidence implies that disruption of tightly regulated Wnt signaling may constitute a key pathological event in AD. In this context, drug targets aimed at rescuing Wnt signaling may prove to be a constructive therapeutic strategy for AD.

    Ageing research reviews 2009;8;2;71-82

  • Disrupted in schizophrenia 1 regulates neuronal progenitor proliferation via modulation of GSK3beta/beta-catenin signaling.

    Mao Y, Ge X, Frank CL, Madison JM, Koehler AN, Doud MK, Tassa C, Berry EM, Soda T, Singh KK, Biechele T, Petryshen TL, Moon RT, Haggarty SJ and Tsai LH

    Howard Hughes Medical Institute, Cambridge, MA 02139, USA.

    The Disrupted in Schizophrenia 1 (DISC1) gene is disrupted by a balanced chromosomal translocation (1; 11) (q42; q14.3) in a Scottish family with a high incidence of major depression, schizophrenia, and bipolar disorder. Subsequent studies provided indications that DISC1 plays a role in brain development. Here, we demonstrate that suppression of DISC1 expression reduces neural progenitor proliferation, leading to premature cell cycle exit and differentiation. Several lines of evidence suggest that DISC1 mediates this function by regulating GSK3beta. First, DISC1 inhibits GSK3beta activity through direct physical interaction, which reduces beta-catenin phosphorylation and stabilizes beta-catenin. Importantly, expression of stabilized beta-catenin overrides the impairment of progenitor proliferation caused by DISC1 loss of function. Furthermore, GSK3 inhibitors normalize progenitor proliferation and behavioral defects caused by DISC1 loss of function. Together, these results implicate DISC1 in GSK3beta/beta-catenin signaling pathways and provide a framework for understanding how alterations in this pathway may contribute to the etiology of psychiatric disorders.

    Funded by: Howard Hughes Medical Institute; NIGMS NIH HHS: T32 GM007753; NINDS NIH HHS: NS37007, R01 NS037007, R01 NS037007-09

    Cell 2009;136;6;1017-31

  • H-Ras is degraded by Wnt/beta-catenin signaling via beta-TrCP-mediated polyubiquitylation.

    Kim SE, Yoon JY, Jeong WJ, Jeon SH, Park Y, Yoon JB, Park YN, Kim H and Choi KY

    National Research Laboratory of Molecular Complex Control and Department of Biotechnology, BK21 project for Medical Science, Yonsei University, Seoul 120-749, Korea.

    Ras is an important proto-protein that is regulated primarily by GDP/GTP exchange. Here, we report a novel regulatory mechanism whereby turnover of both endogenous and overexpressed H-Ras protein is controlled by beta-TrCP-mediated ubiquitylation, proteasomal degradation and the Wnt/beta-catenin signaling pathway. The interaction of H-Ras with the WD40 domain of beta-TrCP targeted H-Ras for polyubiquitylation and degradation. This process was stimulated by Axin or adenomatous polyposis coli (Apc), and was inhibited by Wnt3a. Ras-mediated cellular transformation was also inhibited by the expression of beta-TrCP and/or Axin. In vivo regulation of Ras stability by Wnt/beta-catenin signaling was determined via measurements of the status of Ras in the intestines of mice stimulated with recombinant Wnt3a by intravenous tail vein injection. The regulation of Ras stability by Wnt/beta-catenin signaling provides a mechanical basis for crosstalk between the Wnt/beta-catenin and the Ras-ERK pathways involved in transformation.

    Journal of cell science 2009;122;Pt 6;842-8

  • Identification of zinc-finger BED domain-containing 3 (Zbed3) as a novel Axin-interacting protein that activates Wnt/beta-catenin signaling.

    Chen T, Li M, Ding Y, Zhang LS, Xi Y, Pan WJ, Tao DL, Wang JY and Li L

    State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.

    Axin, a key modulator of the Wnt/beta-catenin pathway, acts as a scaffold protein in phosphorylating and degrading cytoplasmic beta-catenin. Canonical Wnt proteins appear to stabilize beta-catenin by inducing the interaction of LRP5/6 with Axin. This interaction requires the phosphorylation of the Ser or Thr residues in the PPPP(S/T)PX(T/S) motifs at the intracellular domain of LRP5/6. In this work, we identified a novel Axin-interacting protein, zinc-finger BED domain-containing 3 (Zbed3), by yeast two-hybrid screening. The interaction was confirmed in co-immunoprecipitation experiment in mammalian cells and in vitro pulldown assays. Moreover, we found Zbed3 also contains a PPPPSPT motif, which is crucial to its binding to Axin. The Ser and Thr residues in the motif appear to be also phosphorylated by glycogen synthase kinase 3beta (GSK3beta) and the CKI family kinases, as GSK3beta and CKIepsilon could enhance the interaction of Zbed3 with Axin. Mutation of the Ser (SA) or Thr (TA) residue to Ala in the motif markedly impaired its ability to interact with Axin. Expressing Zbed3, but not these mutants, led to inhibition of GSK3beta-mediated beta-catenin phosphorylation, cytoplasmic beta-catenin accumulation, and activation of lymphoid enhancer binding factor-1-dependent reporter gene transcription. Furthermore, knockdown of Zbed3 with RNA interference attenuated Wnt-induced beta-catenin accumulation, lymphoid enhancer binding factor-1-dependent luciferase reporter activity, and the Wnt target gene expression. These results together indicate that Zbed3 is a novel Axin-binding protein that is involved in Wnt/beta-catenin signaling modulation.

    The Journal of biological chemistry 2009;284;11;6683-9

  • The Bcl-w promoter is activated by beta-catenin/TCF4 in human colorectal carcinoma cells.

    Lapham A, Adams JE, Paterson A, Lee M, Brimmell M and Packham G

    Cancer Research UK Clinical Centre, Cancer Sciences Division, University of Southampton School of Medicine, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK.

    The antiapoptotic BCL-2 family protein BCL-W is often overexpressed in colorectal carcinoma (CRC) where it correlates with advanced stage and expression of p53. In this work we have analysed the Bcl-w promoter to identify potential regulators of BCL-W expression in CRC cells. The Bcl-w promoter was highly active in cell lines derived from CRC as well as other cancer types. Although expression of p53 and BCL-W correlate in CRC, overexpression of wild type or mutant p53 did not significantly alter Bcl-w promoter activity, and deletion of endogenous p53 did not alter the expression of Bcl-w RNA in HCT116 cells. Promoter deletion analysis lead to the identification of a potential binding site for TCF/LEF factors, obligate binding partners for beta-catenin, a downstream target of the WNT signalling pathway. TCF4 and beta-catenin interacted with the Bcl-w promoter in intact HCT116 cells and mutation of this site significantly decreased promoter activity. The activity of the Bcl-w promoter was increased or decreased, respectively, by overexpression of beta-catenin or dominant negative TCF4. beta-catenin is activated in the majority of CRC and these results suggest that BCL-W may function as a downstream effector of inappropriate WNT/beta-catenin signalling.

    Funded by: Cancer Research UK

    Gene 2009;432;1-2;112-7

  • Stabilized beta-catenin in thymic epithelial cells blocks thymus development and function.

    Zuklys S, Gill J, Keller MP, Hauri-Hohl M, Zhanybekova S, Balciunaite G, Na KJ, Jeker LT, Hafen K, Tsukamoto N, Amagai T, Taketo MM, Krenger W and Holländer GA

    Department of Clinical-Biological Sciences, Laboratory of Pediatric Immunology, University of Basel, and Basel University Children's Hospital, Basel, Switzerland.

    Thymic T cell development is dependent on a specialized epithelial microenvironment mainly composed of cortical and medullary thymic epithelial cells (TECs). The molecular programs governing the differentiation and maintenance of TECs remain largely unknown. Wnt signaling is central to the development and maintenance of several organ systems but a specific role of this pathway for thymus organogenesis has not yet been ascertained. In this report, we demonstrate that activation of the canonical Wnt signaling pathway by a stabilizing mutation of beta-catenin targeted exclusively to TECs changes the initial commitment of endodermal epithelia to a thymic cell fate. Consequently, the formation of a correctly composed and organized thymic microenvironment is prevented, thymic immigration of hematopoietic precursors is restricted, and intrathymic T cell differentiation is arrested at a very early developmental stage causing severe immunodeficiency. These results suggest that a precise regulation of canonical Wnt signaling in thymic epithelia is essential for normal thymus development and function.

    Funded by: PHS HHS: R0I-A1057477-01

    Journal of immunology (Baltimore, Md. : 1950) 2009;182;5;2997-3007

  • Beta-catenin induces beta-TrCP-mediated PER2 degradation altering circadian clock gene expression in intestinal mucosa of ApcMin/+ mice.

    Yang X, Wood PA, Ansell CM, Ohmori M, Oh EY, Xiong Y, Berger FG, Peña MM and Hrushesky WJ

    Medical Chronobiology Laboratory, Dorn Research Institute, WJB Dorn Veterans Affairs Medical Center, University of South Carolina, Columbia, SC, USA.

    Proliferation of intestinal epithelial cells is rhythmic throughout the day. This temporal organization occurs through the interaction between the endogenous peripheral circadian clock and pathways controlling cell cycle progression. Per2, a core clock gene with tumour suppresser function, is critical to clock function and to the regulation of cellular proliferation. Circadian disruption, which increases colon cancer incidence, may do so by deregulating clock controlled epithelial cell proliferation. Increased expression of beta-catenin is a contributing cause of most familial and spontaneous human colon cancer and the cause of multiple intestinal neoplasia of the Apc(Min/+) mouse. Here we report that increased beta-catenin destabilizes PER2 clock protein by inducing beta-TrCP, an F-box protein of SCF ubiquitin E3 ligase. In the intestinal mucosa of the Apc(Min/)(+) mouse, the decrease in PER2 protein levels is associated with altered circadian rhythms of clock genes, Per1 and Per2, and clock controlled genes, Dbp and Wee1. These findings suggest that disruption of the peripheral intestinal circadian clock may be intimately involved in beta-catenin induced intestinal epithelial neoplastic transformation in both mouse and man.

    Journal of biochemistry 2009;145;3;289-97

  • Beta-catenin overexpression in Dupuytren's disease is unrelated to disease recurrence.

    Degreef I, De Smet L, Sciot R, Cassiman JJ and Tejpar S

    Orthopaedic Surgery Department, Hand Unit, University Hospitals Leuven, Pellenberg Campus, Weligerveld 1, 3212, Pellenberg, Belgium. ilse.degreef@uz.kuleuven.ac.be

    Recurrence of Dupuytren's contracture is common yet unpredictable, compromising surgical outcome. The alpha-smooth muscle actin-containing myofibroblast is the active contractile cellular component. Based on recent reports on beta-catenin accumulation in Dupuytren's disease, we investigated a possible relation with disease recurrence. We divided a collection of 143 nodules into those from patients with recurrent or nonrecurrent nodules and with a minimal 3-year followup. We randomly selected 12 and 11 samples of each group, respectively. We looked at Dupuytren's diathesis, immunohistologic staining for beta-catenin and alpha-smooth muscle actin, and Luck's histologic stages (zones). The expression of selected Wnt genes was examined with TaqMan PCR in separate histologic zones. All samples showed cytoplasmic and nuclear beta-catenin accumulation in myofibroblasts in involutional zones. The risk score of Abe et al. and Dupuytren's diathesis were greater in the recurrent group. Greater Wnt5a expression in the beta-catenin-accumulating involutional zone was seen. We conclude intracellular beta-catenin accumulation, possibly regulated by upstream Wnt signaling pathway activation and confined in myofibroblasts in the involutional zone of Dupuytren's diathesis, is unrelated to disease recurrence. Clinical parameters for Dupuytren's diathesis remain the best way to predict recurrence risk.

    Clinical orthopaedics and related research 2009;467;3;838-45

  • GnRH-regulated expression of Jun and JUN target genes in gonadotropes requires a functional interaction between TCF/LEF family members and beta-catenin.

    Salisbury TB, Binder AK, Grammer JC and Nilson JH

    School of Molecular Biosciences, 639 Fulmer Hall, Washington State University 99164-4660, USA.

    GnRH regulates gonadotrope function through a complex transcriptional network that includes three members of the immediate early gene family: Egr1, Jun, and Atf3. These DNA-binding proteins act alone or in pairs to confer hormonal responsiveness to Cga, Lhb, Fshb, and Gnrhr. Herein we suggest that the transcriptional response of Jun requires a functional interaction between the T-cell factor (TCF)/lymphoid enhancer factor (LEF) family of DNA-binding proteins and beta-catenin (officially CTNNB1), a coactivator of TCF/LEF. Supporting data include demonstration that GnRH increases activity of TOPflash, a TCF/LEF-dependent luciferase reporter, in LbetaT2 cells, a gonadotrope-derived cell line. Additional cotransfection experiments indicate that a dominant-negative form of TCF7L2 (TCFDN) that binds DNA, but not beta-catenin, blocks GnRH induction of TOPflash. Overexpression of AXIN, an inhibitor of beta-catenin, also reduces GnRH stimulation of TOPflash. Transduction of LbetaT2 cells with TCFDN adenoviruses diminishes GnRH stimulation of Jun mRNA without altering expression of Egr1 and Atf3, two other immediate early genes that confer GnRH responsiveness. Reduction of beta-catenin in LbetaT2 cells, through stable expression of short hairpin RNA, also selectively compromises GnRH regulation of Jun expression and levels of JUN protein. Finally, overexpression of TCFDN attenuates GnRH regulation of Cga promoter activity, a known downstream target of JUN. Together, these results indicate that GnRH regulation of Jun transcription requires a functional interaction between TCF/LEF and beta-catenin and that alteration of either impacts expression of JUN downstream targets such as Cga.

    Funded by: NICHD NIH HHS: R01 HD055776

    Molecular endocrinology (Baltimore, Md.) 2009;23;3;402-11

  • Protease activated receptor-1, PAR1, promotes placenta trophoblast invasion and beta-catenin stabilization.

    Grisaru-Granovsky S, Maoz M, Barzilay O, Yin YJ, Prus D and Bar-Shavit R

    Department of Oncology, Hadassah-University Medical Center, Jerusalem, Israel.

    Despite extensive efforts toward elucidation of the molecular pathway controlling cytotrophoblast (CTB) invasion to the uterine decidua, it remains poorly defined. There are striking similarities between tumor cell invasion and cytotrophoblast implantation to the deciduas whereby the role of Protease Activated Receptors (PARs) and wnt signaling is well recognized. We examine here consequences of modulation of PAR1 and PAR2 expression and function on CTB invasion and beta-catenin stabilization. Toward this end, we utilized a model system of extravillous trophoblast (EVT) organ culture and various placenta cell lines (e.g., JAR and HTR-8/Svneo). Activation of PAR1 induces EVT invasion while hPar1-SiRNA and PAR1 antagonist SCH79797--effectively inhibited it. In parallel, the Wnt inhibitor Dickkopf-1 (Dkk1) similarly inhibited it. Nuclear localization of beta-catenin is seen only after PAR1 activation, and is markedly reduced following the application of hPar1-SiRNA construct and PAR1 antagonist in CTBs. In contrast, PAR2 elicited a low cytoplasmic beta-catenin level as also proliferation and invasion. In the non-activated CTBs in-comparison, beta-catenin appeared limited to the membrane pools. Concomitantly, a temporal regulated pattern of Wnt-4, 5a, 7b, 10a, 10b expression is seen along PAR1 appearance. Enforced expression of Wnt antagonists, Secreted Frizzled Related Proteins; SFRP2 & 5; into HTR-8/Svneo, resulted with a markedly reduced nuclear beta-catenin levels, similar to the effect obtained by hPar1-SiRNA treatment. Identification of PAR1 downstream target/s may nonetheless contribute to the formation of a future platform system for eliciting a firm placenta-uterus interactions and to the definition of late pregnancy outcomes.

    Journal of cellular physiology 2009;218;3;512-21

  • Unique phenotype of hepatocellular cancers with exon-3 mutations in beta-catenin gene.

    Cieply B, Zeng G, Proverbs-Singh T, Geller DA and Monga SP

    Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA.

    Unlabelled: Wnt/beta-catenin signaling plays an important role in liver development and regeneration. Its aberrant activation, however, is observed in a subset of primary hepatocellular cancers (HCCs). In the current study, we compare and contrast the tumor characteristics of HCC in the presence or absence of mutations in the beta-catenin gene (CTNNB1). Frozen HCCs (n = 32), including five fibrolamellar (FL) variants, and control livers (n = 3) from Health Sciences Tissue Bank and Department of Surgery at the University of Pittsburgh Medical Center, were examined for mutations in CTNNB1, protein levels of beta-catenin, tyrosine-654-phosphorylated-beta-catenin (Y654-beta-catenin), and glutamine synthetase (GS). Missense mutations in the exon-3 of CTNNB1were identified in 9/32 HCCs. Total beta-catenin levels were higher than controls in most tumors; however, GS was exclusively increased in HCCs with mutations. Phenotypically, greater percentages of mutated HCCs showed macrovascular and microvascular invasion. Also, the tumor size was greater than double in mutated HCCs. High levels of total beta-catenin protein were observed in multinodular tumors independent of beta-catenin mutations. In addition, significant cases with mutations showed absence of cirrhosis. Finally, the highest levels of Y654-beta-catenin were exclusively observed in fibrolamellar (FL)-HCC cases.

    Conclusion: Thus, HCCs that harbor missense mutations in exon-3 of CTNNB1 exhibit, histologically, a more aggressive phenotype. Also, CTNNB1 mutations might lead to HCC in the absence of cirrhosis. Finally, FL-HCC cases display a unique up-regulation of tyrosine-phosphorylated-beta-catenin, suggesting robust receptor tyrosine kinase signaling in this tumor type.

    Funded by: NCI NIH HHS: 1R01CA124414, R01 CA124414-02; NIDDK NIH HHS: 1R01DK62277

    Hepatology (Baltimore, Md.) 2009;49;3;821-31

  • Canonical WNT signalling determines lineage specificity in Wilms tumour.

    Fukuzawa R, Anaka MR, Weeks RJ, Morison IM and Reeve AE

    Cancer Genetics Laboratory, Department of Biochemistry, University of Otago, Dunedin, New Zealand. ryuji.fukuzawa@otago.ac.nz

    Wilms tumours (WTs) have two distinct types of histology with or without ectopic mesenchymal elements, suggesting that WTs arise from either the mesenchymal or epithelial nephrogenic lineages. Regardless of the presence or absence of CTNNB1 mutations, nuclear accumulation of beta-catenin is often observed in WTs with ectopic mesenchymal elements. Here, we addressed the relationship between the WNT-signalling pathway and lineage in WTs by examining CTNNB1 and WT1 mutations, nuclear accumulation of beta-catenin, tumour histology and gene expression profiles. In addition, we screened for mutations in WTX, which has been proposed to be a negative regulator of the canonical WNT-signalling pathway. Unsupervised clustering analysis identified two classes of tumours: mesenchymal lineage WNT-dependent tumours, and epithelial lineage WNT-independent tumours. In contrast to the mesenchymal lineage specificity of CTNNB1 mutations, WTX mutations were surprisingly observed in both lineages. WTX-mutant WTs with ectopic mesenchymal elements had nuclear accumulation of beta-catenin, upregulation of WNT target genes and an association with CTNNB1 mutations in exon 7 or 8. However, epithelial lineage WTs with WTX mutations had no indications of active WNT signalling, suggesting that the involvement of WTX in the WNT-signalling pathway may be lineage dependent, and that WTX may have an alternative function to its role in the canonical WNT-signalling pathway.

    Oncogene 2009;28;8;1063-75

  • The aurora kinase A regulates GSK-3beta in gastric cancer cells.

    Dar AA, Belkhiri A and El-Rifai W

    Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.

    Aurora kinase A (AURKA) is located at 20q13, a region that is frequently amplified in gastric cancer. In this study, we have investigated the role of AURKA in regulating glycogen synthase kinase (GSK)-3beta and beta-catenin/TCF complex in gastric cancer cells. Our results demonstrate a significant increase in the phosphorylation of GSK-3beta at Ser 9 following the overexpression of AURKA in AGS cells. The immunoprecipitation with antibodies specific for AURKA and GSK-3beta indicated that the two proteins coexist in the same protein complex. The recombinant human AURKA protein phosphorylated the GSK-3beta protein at Ser 9 in a concentration-dependent manner, in vitro. The phosphorylation of beta-catenin (Ser33/37/Thr41) by GSK-3beta is known to target beta-catenin towards degradation. In line with our findings, the increase in phospho-GSK-3beta level was accompanied by a significant decrease in beta-catenin phosphorylation (Ser33/37/Thr41) and accumulation of beta-catenin protein. The knockdown of AURKA reversed the phosphorylation of GSK-3beta and the beta-catenin protein levels. The immunofluorescence analysis demonstrated colocalization of AURKA and GSK-3beta proteins and a significant increase in the nuclear beta-catenin levels in cells overexpressing AURKA. The beta-catenin/TCF transcription activity was measured using the pTopFlash and its mutant pFopFlash luciferase reporter vectors. Indeed, AURKA overexpression led to a significant increase in the pTopFlash reporter activity, whereas kinase dead AURKA mutant (D274A) had no effect. Consistent with these findings, we detected a significant mRNA up-regulation of several direct targets of the beta-catenin/TCF transcription complex (cyclin D1, c-MYC, c-MYC-binding protein, CLDN1, FGF18 and vascular endothelial growth factor), and a two-fold increase in the proliferation rate in AURKA overexpressing cells. We conclude that the AURKA/GSK-3beta interaction is important in regulating beta-catenin, underscoring a novel oncogenic potential for AURKA in gastric tumorigenesis.

    Funded by: NCI NIH HHS: CA95103, P50 CA095103, P50 CA095103-07, R01 CA131225, R01 CA131225-01A2

    Oncogene 2009;28;6;866-75

  • Targeting PKC: a novel role for beta-catenin in ER stress and apoptotic signaling.

    Raab MS, Breitkreutz I, Tonon G, Zhang J, Hayden PJ, Nguyen T, Fruehauf JH, Lin BK, Chauhan D, Hideshima T, Munshi NC, Anderson KC and Podar K

    LeBow Institute for Myeloma Therapeutics and Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA. marc_raab@dfci.harvard.edu

    Targeting protein kinase C (PKC) isoforms by the small molecule inhibitor enzastaurin has shown promising preclinical activity in a wide range of tumor cells. We further delineated its mechanism of action in multiple myeloma (MM) cells and found a novel role of beta-catenin in regulating growth and survival of tumor cells. Specifically, inhibition of PKC leads to rapid accumulation of beta-catenin by preventing the phosphorylation required for its proteasomal degradation. Microarray analysis and small-interfering RNA (siRNA)-mediated gene silencing in MM cells revealed that accumulated beta-catenin activates early endoplasmic reticulum stress signaling via eIF2alpha, C/EBP-homologous protein (CHOP), and p21, leading to immediate growth inhibition. Furthermore, accumulated beta-catenin contributes to enzastaurin-induced cell death. Sequential knockdown of beta-catenin, c-Jun, and p73, as well as overexpression of beta-catenin or p73 confirmed that accumulated beta-catenin triggers c-Jun-dependent induction of p73, thereby conferring MM cell apoptosis. Our data reveal a novel role of beta-catenin in endoplasmic reticulum (ER) stress-mediated growth inhibition and a new proapoptotic mechanism triggered by beta-catenin on inhibition of PKC isoforms. Moreover, we identify p73 as a potential novel therapeutic target in MM. Based on these and previous data, enzastaurin is currently under clinical investigation in a variety of hematologic malignancies, including MM.

    Funded by: NCI NIH HHS: P01 CA078378, P01 CA78378, P50 CA100707, R01 CA050947, R01 CA50947

    Blood 2009;113;7;1513-21

  • Dynamic complexes of A-type lamins and emerin influence adipogenic capacity of the cell via nucleocytoplasmic distribution of beta-catenin.

    Tilgner K, Wojciechowicz K, Jahoda C, Hutchison C and Markiewicz E

    The School of Biological and Biomedical Sciences, The University of Durham, Durham, UK.

    It is well documented that adipogenic differentiation of the cell is associated with downregulation of Wnt/beta-catenin signalling. Using preadipocytes and dermal fibroblasts, we have found that activation of the adipogenic program was associated with marked changes in the expression of nuclear beta-catenin-interacting partners, emerin and lamins A/C, to influence expression and activation of peroxisome proliferators-activated receptors gamma (PPARgamma). In addition, silencing of protein expression with siRNA revealed that beta-catenin and emerin influenced each other's levels of expression and the onset of adipogenesis, suggesting that changes in the expression of nuclear lamina proteins were intimately linked to the stability of beta-catenin. By contrast, dermal fibroblasts, which are emerin null, demonstrated increased nuclear accumulation of stable beta-catenin and constant lamin expression. This was also associated with an unusual adipogenic capacity of the cells, with adipogenesis occurring in the presence of activated beta-catenin but declining upon silencing of the protein expression with siRNA. We propose that the process of adipogenesis is affected by a dynamic link between complexes of emerin and lamins A/C at the nuclear envelope and nucleocytoplasmic distribution of beta-catenin, to influence cellular plasticity and differentiation.

    Funded by: Biotechnology and Biological Sciences Research Council; Medical Research Council: G0500501, MC_U105960384

    Journal of cell science 2009;122;Pt 3;401-13

  • Aberrant beta-catenin expression and adenomatous polyposis coli gene mutation in ameloblastoma and odontogenic carcinoma.

    Siriwardena BS, Kudo Y, Ogawa I, Tilakaratne WM and Takata T

    Department of Oral Maxillofacial Pathobiology, Division of Frontier Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553, Japan.

    The Wnt pathway is involved in carcinogenesis and three regulatory genes of the Wnt pathway, APC (adenomatous polyposis coli), beta-catenin and Axin are frequently mutated in some primary human cancers. This study was conducted to clarify the relation of beta-catenin accumulation and the mutation of the CTNNB1 (beta-catenin) gene with the mutation of APC gene in the process of development of odontogenic tumors including ameloblastoma and odontogenic carcinoma (OC). beta-Catenin accumulation was examined by immunohistochemistry in formalin-fixed, paraffin-embedded samples of six ameloblastomas and eight OCs. We also performed a mutation analysis of CTNNB1 and APC to examine the cause of beta-catenin accumulation. All ameloblastoma cases and six out of eight (75%) OC cases exhibited beta-catenin accumulation in the nucleus. CTNNB1 mutation was only found in one OC case, whereas three of six (50%) ameloblastoma cases and two out of eight (25%) OC cases had APC mutations within the mutational cluster region. Our findings suggest that aberrant beta-catenin expression and APC missense mutation may play an important role for the pathogenesis of epithelial odontogenic tumors.

    Oral oncology 2009;45;2;103-8

  • Aberrant nuclear beta-catenin expression in the spindle or corded cells in so-called corded and hyalinized endometrioid carcinomas. Another critical role of the unique morphological feature.

    Wani Y, Saegusa M and Notohara K

    Department of Pathology, Kurashiki Central Hospital, Japan. yw7144@kchnet.or.jp

    Corded and hyalinized endometrioid carcinoma (CHEC), showing spindle and/or corded (SPICO) cells often in the background of hyalinized stroma, is a rare variant of uterine endometrioid carcinomas. The aim of our study was to explore the status of cell-adhesion molecules (beta-catenin, E-cadherin) in CHECs and to survey whether immunostains for beta-catenin and p53 can help to distinguish CHECs from their morphological mimics: malignant mixed mullerian tumors (MMMTs) and uterine tumors resembling ovarian sex-cord tumors (UTROSCTs). Immunohistochemistry was performed and scored for each element as follows: 0: negative, 1+: <10% positive cells, 2+: 10-30%, 3+: >30%. The SPICO patterns were classified as spindle/fusiform; 3, corded; 1, and both; 2. SPICO components consisted of <10%: 4, 10-30%: 1, >30%: 1. Five contained squamous components. In SPICO elements of all CHECs, nuclear beta-catenin expression (score: 1+; 1, 2+; 2, 3+; 3) and complete loss of membranous expression of E-cadherin was observed. In contrast, comparable components (sarcomatous ones for eight MMMTs or sex-cord-like ones for six UTROSCTs) showed no nuclear positivity for beta-catenin. p53 expression was observed in SPICO (64.7%), sarcomatous (87.5%), and sex-cord-like (50%) components, and sarcomatous areas of most MMMTs notably showed diffuse and intense staining. Sequence analysis of PCR amplification products of exon 3 of the beta-catenin gene revealed mutation in all cases, except two lacking SPICO components represented on microdissected areas. Our results suggest that alterations in beta-catenin/E-cadherin complex play a critical role in SPICO features. Immunostain for beta-catenin and p53 is a promising approach for distinguishing CHECs from MMMTs and UTROSCTs.

    Histology and histopathology 2009;24;2;149-55

  • Changes in immunoexpression of E-cadherin and beta-catenin in oral squamous cell carcinoma with and without nodal metastasis.

    Lopes FF, da Costa Miguel MC, Pereira AL, da Cruz MC, de Almeida Freitas R, Pinto LP and de Souza LB

    Dentistry School, Federal University of Maranhão, São Luiz, Maranhão, Brazil.

    The aim of this study is to analyze the immunohistochemical expression of E-cadherin and beta-catenin in oral squamous cell carcinoma to better understand the biological behavior of this lesion. The sample consisted of 15 cases of the tongue and 15 of the lower lip. The pattern and intensity of the labeling and the analysis of the percentage of tumor cells immunopositive in membrane for E-cadherin and beta-catenin were related to the anatomic location of the lesion, the presence or absence of nodal metastasis, and the histological gradation of malignancy in the tumor invasion front. The presence or absence of cytoplasmic and nuclear labeling was also recorded. The membrane expression for E-cadherin and beta-catenin predominately displayed a heterogeneous pattern in the carcinomas studied. No significant difference was observed between the expression pattern and the quantity of cells immunopositive for E-cadherin and beta-catenin and the anatomic location of the lesion or the presence or absence of nodal metastasis. However, a statistically significant difference was found between the reduced expressio\n of these proteins and the high malignancy score. The reduced immunoexpression of these proteins in the membrane may be related to the high degree of cell indifferentiation in cases of oral squamous cell carcinoma with high scores.

    Annals of diagnostic pathology 2009;13;1;22-9

  • Expression and tissue localization of beta-catenin, alpha-actinin and chondroitin sulfate proteoglycan 6 is modulated during rat and human left ventricular hypertrophy.

    Ridinger H, Rutenberg C, Lutz D, Buness A, Petersen I, Amann K and Maercker C

    RZPD German Resource Center for Genome Research, 69120 Heidelberg, Germany.

    Left ventricular hypertrophy (LVH) correlates with chronic renal failure and is one of the most important causes of cardiac mortality. The understanding of the molecular complexity of the disease will help to find biomarkers that open new perspectives about early diagnosis and therapy. This work describes the identification of mediators during pathogenesis relevant for structural remodeling processes of cardiac tissue in uremic LVH. An established rat model of chronic renal failure allowed whole-genome transcriptome analyses as well as the investigation of differential expressed proteins in uremic LVH. The localization of potential biomarkers encoded by candidate genes was done by immunohistochemical analyses of cardiac tissue of the animal model as well as cardiac sections of LVH diseased patients. In addition, the induction of human cardiac fibroblasts (HCF) and human umbilical vein endothelial cells (HUVEC) with the LVH mediator angiotensin II enabled us to investigate uremic LVH progression in vitro. These results point to alterations of myocardial intercellular and cell-matrix contacts in hypertrophic cardiac tissue. Obviously, structural changes of the extracellular matrix are significantly modulated by beta-catenin associated signaling pathways. Interestingly, intracellular translocation of beta-catenin, alpha-actinin and chondroitin sulfate proteoglycan 6 (CSPG6/SMC3) was observed in the animal model and in LVH patients. Our results show that the parallel investigation of rat and human cardiac tissue as well as human cellular models in vitro represents a promising strategy to identify reliable biomarkers of LVH.

    Experimental and molecular pathology 2009;86;1;23-31

  • PCDH24-induced contact inhibition involves downregulation of beta-catenin signaling.

    Ose R, Yanagawa T, Ikeda S, Ohara O and Koga H

    Laboratory of Medical Genomics, Department of Human Genome Research, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan.

    Elevated expression of the protocadherin LKC (PCDH24) in HCT116 colon carcinoma cells has been shown to induce contact inhibition, thereby completely abolishing tumor formation in vivo (Carcinogenesis, 2002; 23(7):1139-1148). To clarify the molecular mechanism behind this effect, we performed 2-DE/MS and DNA microarray analyses in order to compare protein and gene expression patterns of parental HCT116 and PCDH24-expressing HTC116 derivative cells. The data revealed drastic changes in phenotypic markers between parental and PCDH24-expressing cells. We found that in PCDH24-expressing cells beta-catenin, a major player in TCF/lef signaling, is retained in a submembranous location. beta-catenin retention coincided with a subsequent decrease in downstream targets of beta-catenin such as CD44, PLAUR, Myc, cyclin D1 and Met. From these findings we propose a novel model for the suppression of beta-catenin signaling by PCDH24 that leads to contact inhibition.

    Molecular oncology 2009;3;1;54-66

  • Activated Wnt/beta-catenin signaling in melanoma is associated with decreased proliferation in patient tumors and a murine melanoma model.

    Chien AJ, Moore EC, Lonsdorf AS, Kulikauskas RM, Rothberg BG, Berger AJ, Major MB, Hwang ST, Rimm DL and Moon RT

    Institute for Stem Cell and Regenerative Medicine, Department of Medicine, Division of Dermatology, University of Washington School of Medicine, Seattle, WA 98195, USA.

    This study demonstrates that in malignant melanoma, elevated levels of nuclear beta-catenin in both primary tumors and metastases correlate with reduced expression of a marker of proliferation and with improved survival, in contrast to colorectal cancer. The reduction in proliferation observed in vivo is recapitulated in B16 murine melanoma cells and in human melanoma cell lines cultured in vitro with either WNT3A or small-molecule activators of beta-catenin signaling. Consistent with these results, B16 melanoma cells expressing WNT3A also exhibit decreased tumor size and decreased metastasis when implanted into mice. Genome-wide transcriptional profiling reveals that WNT3A up-regulates genes implicated in melanocyte differentiation, several of which are down-regulated with melanoma progression. These findings suggest that WNT3A can mediate transcriptional changes in melanoma cells in a manner reminiscent of the known role of Wnt/beta-catenin signaling in normal melanocyte development, thereby altering melanoma cell fate to one that may be less proliferative and potentially less aggressive. Our results may explain the observed loss of nuclear beta-catenin with melanoma progression in human tumors, which could reflect a dysregulation of cellular differentiation through a loss of homeostatic Wnt/beta-catenin signaling.

    Funded by: Howard Hughes Medical Institute; Intramural NIH HHS

    Proceedings of the National Academy of Sciences of the United States of America 2009;106;4;1193-8

  • Large-scale structural analysis of the classical human protein tyrosine phosphatome.

    Barr AJ, Ugochukwu E, Lee WH, King ON, Filippakopoulos P, Alfano I, Savitsky P, Burgess-Brown NA, Müller S and Knapp S

    University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK. alastair.barr@sgc.ox.ac.uk

    Protein tyrosine phosphatases (PTPs) play a critical role in regulating cellular functions by selectively dephosphorylating their substrates. Here we present 22 human PTP crystal structures that, together with prior structural knowledge, enable a comprehensive analysis of the classical PTP family. Despite their largely conserved fold, surface properties of PTPs are strikingly diverse. A potential secondary substrate-binding pocket is frequently found in phosphatases, and this has implications for both substrate recognition and development of selective inhibitors. Structural comparison identified four diverse catalytic loop (WPD) conformations and suggested a mechanism for loop closure. Enzymatic assays revealed vast differences in PTP catalytic activity and identified PTPD1, PTPD2, and HDPTP as catalytically inert protein phosphatases. We propose a "head-to-toe" dimerization model for RPTPgamma/zeta that is distinct from the "inhibitory wedge" model and that provides a molecular basis for inhibitory regulation. This phosphatome resource gives an expanded insight into intrafamily PTP diversity, catalytic activity, substrate recognition, and autoregulatory self-association.

    Funded by: Wellcome Trust

    Cell 2009;136;2;352-63

  • Dkk3, downregulated in cervical cancer, functions as a negative regulator of beta-catenin.

    Lee EJ, Jo M, Rho SB, Park K, Yoo YN, Park J, Chae M, Zhang W and Lee JH

    Molecular Therapy Research Center, Sungkyunkwan University, School of Medicine, Seoul 135-710, Korea.

    The Wnt/beta-catenin signaling pathway is activated during the malignant transformation of keratinocytes that originate from the human uterine cervix. Dkk1, 2 and 4 have been shown to modulate the Wnt-induced stabilization of the beta-catenin signaling pathway. However, the function of Dkk3 in this pathway is unknown. Comparison of the Dkk3 gene expression profiles in cervical cancer and normal cervical tissue by cDNA microarray and subsequent real-time PCR revealed that the Dkk3 gene is frequently downregulated in the cancer. Methylation studies showed that the promoter of Dkk3 was methylated in cervical cancer cell lines and 22 (31.4%) of 70 cervical cancer tissue specimens. This promoter methylation was associated with reduced expression of Dkk3 mRNA in the paired normal and tumor tissue samples. Further, the reintroduction of Dkk3 into HeLa cervical cancer cells resulted in reduced colony formation and retarded cell growth. The forced expression of Dkk3 markedly attenuated beta-catenin-responsive luciferase activity in a dose-dependent manner and decreased the beta-catenin levels. By utilizing a yeast two-hybrid screen, betaTrCP, a negative regulator of beta-catenin was identified as a novel Dkk3-interacting partner. Coexpression with betaTrCP synergistically enhanced the inhibitory function of Dkk3 on beta-catenin. The stable expression of Dkk3 blocks the nuclear translocation of beta-catenin, resulting in downregulation of its downstream targets (VEGF and cylcin D), whereas knockdown of Dkk3 abrogates this blocking. We conclude from our finding that Dkk3 is a negative regulator of beta-catenin and its downregulation contribute to an activation of the beta-catenin signaling pathway.

    International journal of cancer 2009;124;2;287-97

  • Pre-TCR-induced beta-catenin facilitates traversal through beta-selection.

    Xu M, Sharma A, Wiest DL and Sen JM

    Lymphocyte Development Unit, Laboratory of Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.

    Pre-TCR induced signals regulate development of the alphabeta TCR lineage cells at the beta-selection checkpoint. We have previously shown that conditional deletion of beta-catenin, a central mediator of Wnt-beta-catenin-T cell factor signaling pathway, impairs traversal through the beta-selection checkpoint. We now provide a molecular basis for the impairment. We demonstrate that pre-TCR signals specifically stabilize beta-catenin in CD4-CD8- double negative thymocytes during beta-selection. Pre-TCR induced Erk activity was required to stabilize beta-catenin. Enforced expression of stabilized beta-catenin was sufficient to mediate aspects of beta-selection including sustained expression of early growth response (Egr) genes. Consistently, deletion of beta-catenin reduced induction of Egr gene expression by the pre-TCR signal and blocked efficient beta-selection. Thus, we demonstrate that pre-TCR induced beta-catenin sustains expression of Egr genes that facilitate traversal through the beta-selection checkpoint.

    Funded by: Intramural NIH HHS: Z01 AG000768-04

    Journal of immunology (Baltimore, Md. : 1950) 2009;182;2;751-8

  • Sustained expression of pre-TCR induced beta-catenin in post-beta-selection thymocytes blocks T cell development.

    Xu M, Sharma A, Hossain MZ, Wiest DL and Sen JM

    Lymphocyte Development Unit, Laboratory of Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.

    Pre-TCR and IL-7R signals regulate beta-selection of thymocytes and then must be down-regulated for further development. However, the molecular events that control down-regulation remain unknown. We and others have previously shown that beta-catenin in cooperation with TCF regulates beta-selection. In this paper, we demonstrate that beta-catenin expression is stringently regulated by intrathymic signals, it is expressed at the highest levels in the pre-TCR signaled thymocytes, and is down-regulated in post-beta-selection thymocytes. Pre-TCR-induced beta-catenin regulates initial stages of pre-TCR signaling including expression of early growth response (Egr) genes but must be down-regulated to express RORgammat, which is essential for maturation to the CD4+CD8+ double positive (DP) stage. Sustained expression of beta-catenin results in the generation of IL-7R-, Egr-, and TGFbeta-expressing pre-DP thymocytes that are blocked in development. These data are consistent with a model in which post-beta-selection, pre-TCR-induced beta-catenin expression must return to background levels for efficient transition to the DP stage.

    Funded by: Intramural NIH HHS: Z01 AG000768-04

    Journal of immunology (Baltimore, Md. : 1950) 2009;182;2;759-65

  • Epithelial cell alpha3beta1 integrin links beta-catenin and Smad signaling to promote myofibroblast formation and pulmonary fibrosis.

    Kim KK, Wei Y, Szekeres C, Kugler MC, Wolters PJ, Hill ML, Frank JA, Brumwell AN, Wheeler SE, Kreidberg JA and Chapman HA

    Pulmonary and Critical Care Division, Department of Medicine, and Cardiovascular Research Institute, UCSF, San Francisco, CA 94143, USA.

    Pulmonary fibrosis, in particular idiopathic pulmonary fibrosis (IPF), results from aberrant wound healing and scarification. One population of fibroblasts involved in the fibrotic process is thought to originate from lung epithelial cells via epithelial-mesenchymal transition (EMT). Indeed, alveolar epithelial cells (AECs) undergo EMT in vivo during experimental fibrosis and ex vivo in response to TGF-beta1. As the ECM critically regulates AEC responses to TGF-beta1, we explored the role of the prominent epithelial integrin alpha3beta1 in experimental fibrosis by generating mice with lung epithelial cell-specific loss of alpha3 integrin expression. These mice had a normal acute response to bleomycin injury, but they exhibited markedly decreased accumulation of lung myofibroblasts and type I collagen and did not progress to fibrosis. Signaling through beta-catenin has been implicated in EMT; we found that in primary AECs, alpha3 integrin was required for beta-catenin phosphorylation at tyrosine residue 654 (Y654), formation of the pY654-beta-catenin/pSmad2 complex, and initiation of EMT, both in vitro and in vivo during the fibrotic phase following bleomycin injury. Finally, analysis of lung tissue from IPF patients revealed the presence of pY654-beta-catenin/pSmad2 complexes and showed accumulation of pY654-beta-catenin in myofibroblasts. These findings demonstrate epithelial integrin-dependent profibrotic crosstalk between beta-catenin and Smad signaling and support the hypothesis that EMT is an important contributor to pathologic fibrosis.

    Funded by: NHLBI NIH HHS: HL88440, K08 HL085290, K08 HL085290-04, K08HL085290, R01 HL044712, R01 HL088440, R01 HL44712, R56 HL088440

    The Journal of clinical investigation 2009;119;1;213-24

  • Expression and clinical significance of Wnt-1 and beta-catenin in nasopharyngeal carcinoma.

    Wang FL, Guo X, Yuan TZ, Cao SM, Rao HL, Hou JH, Shao Q, Li NW and Hong MH

    State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, PR China.

    As signaling molecule and key component of Wnt/beta-catenin signaling pathway respectively, Wnt-1 and beta-catenin are abnormally expressed in several malignancies and correlate with poor prognosis. This study was to investigate the expression and clinical significance of Wnt-1 and beta-catenin in nasopharyngeal carcinoma (NPC).

    Methods: The expression of Wnt-1 and beta-catenin in 111 specimens of NPC was detected by SP immunohistochemistry. Their correlations to relapse-free survival (RFS), metastasis-free survival (MFS) and progression-free survival (PFS) were analyzed.

    Results: The high expression of beta-catenin was observed in 64 (57.7%) of the 111 cases. Its high expression rate was significantly higher in advanced NPC than in early stage NPC (63.1% vs. 40.7%, p = 0.041). The RFS, MFS and PFS were lower in high beta-catenin expression group than in low beta-catenin expression group (p < 0.05). Cox regression analysis demonstrated that beta-catenin was related to poor prognosis of NPC patients. The high expression of Wnt-1 was observed in 68 (61.3%) of the 111 cases, but its expression had no effect on RFS, MFS and PFS (p > 0.05).

    Conclusions: Wnt/beta-catenin signaling pathway may be activated abnormally in some NPC patients. beta-catenin may be a prognostic factor of NPC.

    Ai zheng = Aizheng = Chinese journal of cancer 2009;28;1;72-5

  • Expression and significance of adenomatous polyposis coli, beta-catenin, E-cadherin and cyclin D1 in esophageal squamous cell carcinoma assessed by tissue microarray.

    Peng H, Zhong XY, Liu KP and Li SM

    Department of Pathology, Medical School, Jinan University, Guangzhou, Guangdong, PR China.

    The genesis of esophageal squamous cell carcinoma(ESCC)is a multifactor and multistage process, in which Wnt signaling transduction pathway plays an important role in tumorigenesis and tumor progression. This study was to investigate the roles of four proteins in the Wnt pathway in tumorigenesis of ESCC, and their significances in the early diagnosis of ESCC.

    Methods: The expression of adenomatous polyposis coli (APC), beta-catenin, E-cadherin and cyclinD1 was detected by immunohistochemistry using tissue microarrays consisting of 199 specimens of ESCC, 164 specimens of normal mucosa, 34 specimens of basal cell hyperplasia and 30 specimens of dysplasia adjacent to cancer tissues.

    Results: The positive rates of APC and E-cadherin in ESCC were lower than those in the normal group (69.6% vs. 98.0%, p < 0.01; 19.6% vs. 96.3%, p < 0.01). The abnormal expression rates of beta-catenin and cyclin D1 in ESCC were higher than those in the normal group (65.5% vs. 1.2%,p < 0.01; 70.9% vs. 0.8%, p < 0.01). In accordance with the following order, normal epithelia --> basal cell hyperplasia --> dysplasia --> ESCC, hypoexpression of APC proteins occurred in ESCC, abnormalities of beta-catenin and E-cadherin started to appear in dysplasia, and overexpression of Cyclin D1 emerged from basal cell hyperplasia. From well to poorly differentiated ESCC, the expression of APC, E-cadherin and cyclin D1 were gradually reduced, while beta-catenin was increased. The expression of beta-catenin was not correlated with APC (r = -0.10, p > 0.05), was negatively correlated with E-cadherin (r = -0.31,p < 0.01) and positively correlated with cyclin D1(r = 0.49, p < 0.01).

    Conclusion: APC, E-cadherin, beta-catenin and cyclin D1 may play important roles in tumorigenesis of ESCC. Therefore, detection of E-cadherin, beta-catenin and cyclin D1 proteins may be helpful for the early diagnosis of ESCC.

    Ai zheng = Aizheng = Chinese journal of cancer 2009;28;1;38-41

  • Identification of WNT/beta-CATENIN signaling pathway components in human cumulus cells.

    Wang HX, Tekpetey FR and Kidder GM

    Department of Physiology and Pharmacology, The University of Western Ontario, London, ON, Canada N6A 5C1.

    Signaling via the conserved WNT/beta-CATENIN pathway controls diverse developmental processes. To explore its potential role in the ovary, we investigated the expression of WNTs, frizzled (FZD) receptors and other pathway components in human cumulus cells obtained from oocytes collected for in vitro fertilization. Proteins were detected in cultured cells using immunofluorescence microscopy. Protein-protein interactions were analyzed by means of immunoprecipitation. WNT2, FZD2, FZD3 and FZD9 were identified but WNT1, WNT4 and FZD4 were not detected. WNT2 is co-expressed with FZD2, FZD3 and FZD9. Co-immunoprecipitation using WNT2 antibody demonstrated that WNT2 interacts with both FZD3 and FZD9, but only FZD9 antibody precipitated WNT2. We also identified DVL (disheveled), AXIN, GSK-3beta (glycogen synthase kinase-3beta) and beta-CATENIN. beta-CATENIN is concentrated in the plasma membranes. DVL co-localizes with FZD9 and AXIN in the membranes, but GSK-3beta has little co-localization with AXIN and beta-CATENIN. Interestingly, beta-CATENIN is highly co-localized with FZD9 and AXIN. CDH1 (E-cadherin) was also detected in the plasma membranes and cytoplasm, co-localized with beta-CATENIN, and CDH1 antibody precipitated beta-CATENIN. The results suggest that WNT2 could act through its receptor FZD9 to regulate the beta-CATENIN pathway in cumulus cells, recruiting beta-CATENIN into plasma membranes and promoting the formation of adherens junctions involving CDH1.

    Molecular human reproduction 2009;15;1;11-7

  • PCAF acetylates {beta}-catenin and improves its stability.

    Ge X, Jin Q, Zhang F, Yan T and Zhai Q

    Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, and Graduate School of the Chinese Academy of Sciences, Shanghai, China.

    beta-Catenin plays an important role in development and tumorigenesis. However, the effect of a key acetyltransferase p300/CBP-associated factor (PCAF) on beta-catenin signaling is largely unknown. In this study, we found PCAF could increase the beta-catenin transcriptional activity, induce its nuclear translocation, and up-regulate its protein level by inhibiting its ubiquitination and improving its stability. Further studies showed that PCAF directly binds to and acetylates beta-catenin. The key ubiquitination sites Lys-19 and Lys-49 of beta-catenin were shown as the critical residues for PCAF-induced acetylation and stabilization. Knockdown of PCAF in colon cancer cells markedly reduced the protein level, transcriptional activity, and acetylation level of beta-catenin; promoted cell differentiation; inhibited cell migration; and repressed xenografted tumorigenesis and tumor growth in nude mice. All these data demonstrate that PCAF acetylates beta-catenin and regulates its stability, and they raise the prospect that therapies targeting PCAF may be of clinical use in beta-catenin-driven diseases, such as colon cancer.

    Molecular biology of the cell 2009;20;1;419-27

  • RET/PTC1-driven neoplastic transformation and proinvasive phenotype of human thyrocytes involve Met induction and beta-catenin nuclear translocation.

    Cassinelli G, Favini E, Degl'Innocenti D, Salvi A, De Petro G, Pierotti MA, Zunino F, Borrello MG and Lanzi C

    Department of Experimental Oncology and Laboratories, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

    Activation of the RET gene by chromosomal rearrangements generating RET/PTC oncogenes is a frequent, early, and causative event in papillary thyroid carcinoma (PTC). We have previously shown that, in human primary thyrocytes, RET/PTC1 induces a transcriptional program including the MET proto-oncogene. In PTCs, beta-catenin is frequently mislocated to the cytoplasm nucleus. We investigated the interplay between Ret/ptc1 signaling and Met in regulating the proinvasive phenotype and beta-catenin localization in cellular models of human PTC. Here, we show that Met protein is expressed and is constitutively active in human thyrocytes exogenously expressing RET/PTC1 as well as a mutant (Y451F) devoid of the main Ret/ptc1 multidocking site. Both in transformed thyrocytes and in the human PTC cell line TPC-1, Ret/ptc1-Y451-dependent signaling and Met cooperated to promote a proinvasive phenotype. Accordingly, gene/functional silencing of either RET/PTC1 or MET abrogated early branching morphogenesis in TPC-1 cells. The same effect was obtained by blocking the common downstream effector Akt. Y451 of Ret/ptc1 was required to promote proliferation and nuclear translocation of beta-catenin, suggesting that these oncogene-driven effects are Met-independent. Pharmacologic inhibition of Ret/ptc1 and Met tyrosine kinases by the multitarget small molecule RPI-1 blocked cell proliferation and invasive ability and dislocated beta-catenin from the nucleus. Altogether, these results support that Ret/ptc1 cross talks with Met at transcriptional and signaling levels and promotes beta-catenin transcriptional activity to drive thyrocyte neoplastic transformation. Such molecular network, promoting disease initiation and acquisition of a proinvasive phenotype, highlights new options to design multitarget therapeutic strategies for PTCs.

    Neoplasia (New York, N.Y.) 2009;11;1;10-21

  • Analysis of APC, alpha-, beta-catenins, and N-cadherin protein expression in aggressive fibromatosis (desmoid tumor).

    Ferenc T, Wroński JW, Kopczyński J, Kulig A, Sidor M, Stalińska L, Dziki A and Sygut J

    Department of Biology and Genetics, Medical University, Pl. Hallera 1, 90-647 Lodz, Poland. biolgen@achilles.wam.lodz.pl

    The aims of this study were to analyze the cadherin/catenin adhesion complex in cells from abdominal and extra-abdominal aggressive fibromatosis tumors, and to estimate the correlation between the expression of the tested proteins and the clinical data of the desmoid patients. Immunohistochemistry was used to examine the expression of the cadherin/catenin adhesion complex: APC protein, alpha-, beta-catenin, and N-cadherin in archival material derived from 15 cases of extra-abdominal desmoid tumor (E-AD) and 20 cases of abdominal (AD) desmoid tumor. The tested proteins demonstrated cytoplasmic (c) staining. Furthermore, nuclear (n) or cytoplasmic and nuclear (c+n) staining was observed for beta-catenin. The mean values of the percentage of positive cells for the tested proteins between E-AD vs. AD did not demonstrate any statistically significant difference except for alpha-catenin. In the E-AD group, in both cases of recurrent tumors, no alpha-catenin expression was observed but the expression of this protein was detected in primary tumors. In the groups investigated, no statistically significant correlation was found between alpha-catenin, beta-catenin (c), (n) and (c+n) expression, and tumor size (p>0.1). The results regarding beta-catenin expression obtained in our study confirm the previous findings that nuclear accumulation of this protein plays a crucial role in the pathogenesis of aggressive fibromatosis.

    Pathology, research and practice 2009;205;5;311-24

  • Analysis of candidate genes in occurrence and growth of colorectal adenomas.

    Olschwang S, Vernerey D, Cottet V, Pariente A, Nalet B, Lafon J, Faivre J, Laurent-Puig P, Bonithon-Kopp C and Bonaiti-Pellié C

    Centre de Recherche en Cancérologie de Marseille, INSERM U891, 13009 Marseille, France.

    Predisposition to sporadic colorectal tumours is influenced by genes with minor phenotypic effects. A case-control study was set up on 295 patients treated for a large adenoma matched with polyp-free individuals on gender, age, and geographic origin in a 1 : 2 proportion. A second group of 302 patients treated for a small adenoma was also characterized to distinguish effects on adenoma occurrence and growth. We focussed the study on 38 single nucleotide polymorphisms (SNPs) encompassing 14 genes involved in colorectal carcinogenesis. Effect of SNPs was tested using unconditional logistic regression. Comparisons were made for haplotypes within a given gene and for biologically relevant genes combinations using the combination test. The APC p.Glu1317Gly variant appeared to influence the adenoma growth (P = .04, exact test) but not its occurrence. This result needs to be replicated and genome-wide association studies may be necessary to fully identify low-penetrance alleles involved in early stages of colorectal tumorigenesis.

    Journal of oncology 2009;2009;306786

  • Cadherin-bound beta-catenin feeds into the Wnt pathway upon adherens junctions dissociation: evidence for an intersection between beta-catenin pools.

    Kam Y and Quaranta V

    Cancer Biology Department, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.

    Beta-catenin is an essential component of two cellular systems: cadherin-based adherens junctions (AJ) and the Wnt signaling pathway. A functional or physical connection between these beta-catenin pools has been suggested in previous studies, but not conclusively demonstrated to date. To further examine this intersection, we treated A431 cell colonies with lysophosphatidic acid (LPA), which forces rapid and synchronized dissociation of AJ. A combination of immunostaining, time-lapse microscopy using photoactivatable-GFP-tagged beta-catenin, and image analyses indicate that the cadherin-bound pool of beta-catenin, internalized together with E-cadherin, accumulates at the perinuclear endocytic recycling compartment (ERC) upon AJ dissociation, and can be translocated into the cell nucleus upon Wnt pathway activation. These results suggest that the ERC may be a site of residence for beta-catenin destined to enter the nucleus, and that dissociation of AJ may influence beta-catenin levels in the ERC, effectively affecting beta-catenin substrate levels available downstream for the Wnt pathway. This intersection provides a mechanism for integrating cell-cell adhesion with Wnt signaling and could be critical in developmental and cancer processes that rely on beta-catenin-dependent gene expression.

    Funded by: NIGMS NIH HHS: R01 GM067221

    PloS one 2009;4;2;e4580

  • Dickkopf-1 enhances migration of HEK293 cell by beta-catenin/E-cadherin degradation.

    Kuang HB, Miao CL, Guo WX, Peng S, Cao YJ and Duan EK

    State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P.R. China.

    Migration is an important process during cellular activity and embryo development. We recently showed that Dickkopf-1(Dkk-1), an antagonist of Wnt/ beta-catenin signaling pathway, could promote trophoblast cell invasion during murine placentation. However, mechanism of Dkk-1 action on cell migration was not clear. The objective of this study was to further evaluate the effect of Dkk-1 on cell migration and to identify the underlining mechanisms. Functional assays with stable Dkk-1 transfected HEK293 cells revealed that Dkk-1 expression increased cell migration by decreasing cell-cell adhesion, not cell-matrix adhesion. Treatment with LiCl and Genistein (widely used inhibitor of glycogen synthase kinase-3 and tyrosine protein kinase, respectively.) could inhibit the migration effect of Dkk-1, and significantly increased the membrane localization of beta-catenin and E-cadherin in HEK293 cells transfected with Dkk-1. Further data showed that HEK293 cells transfected with Dkk-1 have significantly decreased accumulation of both beta-catenin and E-cadherin at the cell membrane. Together, our data suggest that Dkk-1 stimulates the release of beta-catenin from cell membrane and facilitates cell migration which accompanies degradation of beta-catenin/E-cadherin.

    Frontiers in bioscience (Landmark edition) 2009;14;2212-20

  • Expression of Notch1, Jagged1 and beta-catenin and their clinicopathological significance in hepatocellular carcinoma.

    Wang M, Xue L, Cao Q, Lin Y, Ding Y, Yang P and Che L

    Department of Pathology, The first Affiliated Hospital, SUN YAT-SEN UNIVERSITY, Guang Zhou City, Guang Dong Province, China.

    The Notch/Jagged signaling pathway is important for cellular differentiation and proliferation. Notch1/Jagged1 can either suppress or promote tumors depending on the cell type and context. beta-catenin, one of the mediators of the Wnt signalling pathway, represents a key element in one of the most important pathways of carcinogenesis. The aim of this study was to examine the expression of Notch1/Jagged1 and beta-catenin in hepatocellular carcinoma and to assign clinicopathological correlations. Immunohistochemical detection of Notch1/Jagged1 and beta-catenin was performed in tissue microarrays including 339 Hepatocellular carcinomas, 174 adjacent non-tumor livers and 94 normal livers. The results showed that the rate of expression was 66%, 98% and 97% for Notch1 and 36%, 85% and 92% for Jagged1 respectively in hepatocellular carcinoma, adjacent non-tumor liver and normal liver. Decreased expression of Notch1/Jagged1 was correlated significantly with Edmondson-Steiner grade. However, nuclear beta-catenin was expressed in 37% of hepatocellular carcinoma tissue, which was significantly higher than its non-tumor counterparts. Increased nuclear beta-catenin expression was correlated with HBs-Ag status and Edmondson-Steiner grade. Moreover, The positive expression of Notch1 was parallel with Jagged1 expression (r =0.235, p=0.000) and reduced Notch1 expression was associated with increased beta-catenin expression in hepatocellular carcinoma (r =-0.125, p =0.023). In conclusion, Notch1/Jagged1 were frequently low expressed in hepatocellular carcinoma and correlated with the high expression of beta-catenin suggesting that downregulation of Notch1/Jagged1 signaling may sustain tumor progression.

    Neoplasma 2009;56;6;533-41

  • Immunohistochemical analyses of beta-catenin and cyclin D1 expression in giant cell tumor of bone (GCTB): a possible role of Wnt pathway in GCTB tumorigenesis.

    Matsubayashi S, Nakashima M, Kumagai K, Egashira M, Naruke Y, Kondo H, Hayashi T and Shindo H

    Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.

    Giant cell tumor of bone (GCTB) is a benign neoplasm but occasionally shows local recurrence, and histologically consists of osteoclast-like giant cells (GC) and stromal mononuclear cells (SC), which are capable of proliferation and osteoblastic differentiation. Activation of Wnt signaling can induce osteoblast differentiation and osteoclastgenesis during bone resorption process. This study analyzed the profiles of beta-catenin and cyclin D1 expression in GCTB to elucidate an involvement of Wnt pathway in tumorigenesis. We performed immunohistochemistry for beta-catenin, cyclin D1, and Ki-67 in 16 GCTB tumors, including 5 recurrent cases that were surgically resected. All 16 cases of GCTB displayed beta-catenin, cyclin D1, and Ki-67 expression. Immunoreactivity for beta-catenin was observed in nuclei of SC and GC. Cyclin D1 immunoreactivity was found mainly in nuclei of GC, while Ki-67 immunoreactivity was restricted to nuclei of SC. The nuclear beta-catenin labeling index (LI) in both SC (60.6 vs. 41.8%, p=0.074) and GC (41.7 vs. 20.1%, p=0.095) was higher in recurrent tumors than in primary tumors in all the 4 cases. However, Ki-67 LI in SC (18.8 vs. 19.9%, p=0.851) and cyclin D1 LI in GC (55.4 vs. 70.1%, p=0.225) were not higher in recurrent tumors than in primary tumors. Our results suggested activation of Wnt/ beta-catenin pathway in GCTB tumorigenesis. Since cyclin D1 in GC was never associated with the expression of the well-known proliferative marker Ki-67, cyclin D1 expression might play a role in GC formation instead of promoting cell proliferation during GCTB tumorigenesis. Importantly, it was suggested that the nuclear beta-catenin staining level might be associated with tumor recurrence in GCTB.

    Pathology, research and practice 2009;205;9;626-33

  • Post-transcriptional regulation of cadherin-11 expression by GSK-3 and beta-catenin in prostate and breast cancer cells.

    Farina AK, Bong YS, Feltes CM and Byers SW

    Departments of Oncology and Biochemistry, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, DC, United States of America.

    Background: The cell-cell adhesion molecule cadherin-11 is important in embryogenesis and bone morphogenesis, invasion of cancer cells, lymphangiogenesis, homing of cancer cells to bone, and rheumatoid arthritis. However, very little is known about the regulation of cadherin-11 expression.

    Here we show that cell density and GSK-3beta regulate cadherin-11 levels in cancer cells. Inactivation of GSK3beta with lithium chloride or the GSK3 inhibitor BIO and GSK3beta knockdown with siRNA repressed cadherin-11 mRNA and protein levels. RNA Polymerase II chromatin immunoprecipitation experiments showed that inhibition of GSK3 does not affect cadherin-11 gene transcription. Although the cadherin-11 3'UTR contains putative microRNA target sites and is regulated by Dicer, its stability is not regulated by GSK3 inhibition or density. Our data show that GSK3beta regulates cadherin-11 expression in two ways: first a beta-catenin-independent regulation of cadherin-11 steady state mRNA levels, and second a beta-catenin-dependent effect on cadherin-11 3'UTR stability and protein translation.

    Conclusions: Cadherin-11 mRNA and protein levels are regulated by the activity of GSK3beta and a significant degree of this regulation is exerted by the GSK3 target, beta-catenin, at the level of the cadherin-11 3'UTR.

    Funded by: NCI NIH HHS: P30 CA051008

    PloS one 2009;4;3;e4797

  • Short hairpin RNA targeting beta-catenin suppresses cell proliferation and induces apoptosis in human gastric carcinoma cells.

    Jiang H, Xia J, Kang J, Ding Y and Wu W

    Department of Gastrointestinal Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China.

    Objective: Aberrant activation of Wnt/beta-catenin signaling is involved in various cancers, including human gastric cancer. Here we investigate the role of Wnt/beta-catenin signaling in regulating gastric cancer cell apoptosis.

    Expression of beta-catenin was investigated after transfection with beta-catenin short hairpin RNA (shRNA) in gastric cancer cells by Western blotting and immunofluorescence analysis. beta-catenin/T-cell factor transcriptional activity was also investigated by using a luciferase reporter assay. Next, the effects of beta-catenin shRNA on cell proliferation and apoptosis were evaluated by the 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide assay and flow cytometric analysis. To investigate the precise mechanism of these effects, a comprehensive analysis was performed using a cDNA microarray.

    Results: shRNA targeting beta-catenin resulted in a significant decrease in beta-catenin expression, and its nuclear localization and cell proliferation. Meanwhile, increased cell apoptosis was confirmed. The comprehensive analysis showed that shRNA targeting beta-catenin upregulated 26 apoptosis-related genes (including PERP, TRAF3, PDCD2, TNFRSF25, AKT2 and YWHAZ) and downregulated 48 apoptosis-related genes (including MALT1, IRAK1, TNFAIP3, PPP1R13L, TRIP and YWHAB) in gastric cancer cells. Pathway analysis suggested that the nuclear factor-kappaB pathway was involved in beta-catenin knockdown-induced apoptosis.

    Conclusions: Attenuation of beta-catenin by shRNA resulted in suppressed cell proliferation and apparent apoptosis, suggesting that beta-catenin may be a target for therapy of gastric cancer.

    Scandinavian journal of gastroenterology 2009;44;12;1452-62

  • Type-1 Collagen differentially alters beta-catenin accumulation in primary Dupuytren's Disease cord and adjacent palmar fascia cells.

    Vi L, Njarlangattil A, Wu Y, Gan BS and O'Gorman DB

    Cell and Molecular Biology Laboratory, Hand and Upper Limb Centre, Lawson Health Research Institute, London, Canada. lvi@uwo.ca

    Background: Dupuytren's Disease (DD) is a debilitating contractile fibrosis of the palmar fascia characterised by excess collagen deposition, contractile myofibroblast development, increased transforming growth factor-beta levels and beta-catenin accumulation. The aim of this study was to determine if a collagen-enriched environment, similar to in vivo conditions, altered beta-catenin accumulation by primary DD cells in the presence or absence of transforming growth factor-beta.

    Methods: Primary DD and patient matched, phenotypically normal palmar fascia (PF) cells were cultured in the presence or absence of type-1 collagen and transforming growth factor-beta1. beta-catenin and alpha-smooth muscle actin levels were assessed by western immunoblotting and immunofluorescence microscopy.

    Results: DD cells display a rapid depletion of cellular beta-catenin not evident in patient-matched PF cells. This effect was not evident in either cell type when cultured in the absence of type-1 collagen. Exogenous addition of transforming growth factor-beta1 to DD cells in collagen culture negates the loss of beta-catenin accumulation. Transforming growth factor-beta1-induced alpha-smooth muscle actin, a marker of myofibroblast differentiation, is attenuated by the inclusion of type-1 collagen in cultures of DD and PF cells.

    Conclusion: Our findings implicate type-1 collagen as a previously unrecognized regulator of beta-catenin accumulation and a modifier of TGF-beta1 signaling specifically in primary DD cells. These data have implications for current treatment modalities as well as the design of in vitro models for research into the molecular mechanisms of DD.

    Funded by: Canadian Institutes of Health Research: 84247

    BMC musculoskeletal disorders 2009;10;72

  • Constitutive activation of the Wnt canonical pathway in mantle cell lymphoma.

    Gelebart P, Anand M, Armanious H, Peters AC, Dien Bard J, Amin HM and Lai R

    Department of Laboratory Medicine and Pathology, Cross Cancer Institute and University of Alberta, Edmonton, AB.

    Aberrations of the Wnt canonical pathway (WCP) are known to contribute to the pathogenesis of various types of cancer. We hypothesize that these defects may exist in mantle cell lymphoma (MCL). Both the upstream and downstream aspects of WCP were examined in MCL cell lines and tumors. Using WCP-specific oligonucleotide arrays, we found that MCL highly and consistently expressed Wnt3 and Wnt10. beta-catenin, a transcriptional factor that is a downstream target of WCP, is localized to the nucleus and transcriptionally active in all 3 MCL cell lines examined. By immunohistochemistry, 33 (52%) of 64 MCL tumors showed nuclear localization of beta-catenin, which significantly correlated with the expression of the phosphorylated/inactive form of GSK3beta (p-GSK3beta; P = .011, Fisher). GSK3beta inactivation is directly linked to WCP stimulation, since addition of recombinant sFRP proteins (a naturally occurring decoy for the Wnt receptors) resulted in a significant decrease in p-GSK3beta. Down-regulation of DvL-2 (an upstream signaling protein in WCP) by siRNA or selective inhibition of beta-catenin using quercetin significantly decreased cell growth in MCL cell lines. To conclude, WCP is constitutively activated in a subset of MCL and it appears to promote tumorigenesis in MCL.

    Funded by: NCI NIH HHS: CA114395, K08 CA114395

    Blood 2008;112;13;5171-9

  • Hepatic stem-like phenotype and interplay of Wnt/beta-catenin and Myc signaling in aggressive childhood liver cancer.

    Cairo S, Armengol C, De Reyniès A, Wei Y, Thomas E, Renard CA, Goga A, Balakrishnan A, Semeraro M, Gresh L, Pontoglio M, Strick-Marchand H, Levillayer F, Nouet Y, Rickman D, Gauthier F, Branchereau S, Brugières L, Laithier V, Bouvier R, Boman F, Basso G, Michiels JF, Hofman P, Arbez-Gindre F, Jouan H, Rousselet-Chapeau MC, Berrebi D, Marcellin L, Plenat F, Zachar D, Joubert M, Selves J, Pasquier D, Bioulac-Sage P, Grotzer M, Childs M, Fabre M and Buendia MA

    Oncogenesis and Molecular Virology Unit, Institut Pasteur, Paris Cedex 15, France.

    Hepatoblastoma, the most common pediatric liver cancer, is tightly linked to excessive Wnt/beta-catenin signaling. Here, we used microarray analysis to identify two tumor subclasses resembling distinct phases of liver development and a discriminating 16-gene signature. beta-catenin activated different transcriptional programs in the two tumor types, with distinctive expression of hepatic stem/progenitor markers in immature tumors. This highly proliferating subclass was typified by gains of chromosomes 8q and 2p and upregulated Myc signaling. Myc-induced hepatoblastoma-like tumors in mice strikingly resembled the human immature subtype, and Myc downregulation in hepatoblastoma cells impaired tumorigenesis in vivo. Remarkably, the 16-gene signature discriminated invasive and metastatic hepatoblastomas and predicted prognosis with high accuracy.

    Cancer cell 2008;14;6;471-84

  • APC is essential for targeting phosphorylated beta-catenin to the SCFbeta-TrCP ubiquitin ligase.

    Su Y, Fu C, Ishikawa S, Stella A, Kojima M, Shitoh K, Schreiber EM, Day BW and Liu B

    Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15213, USA.

    Ubiquitin-dependent proteolysis is an important mechanism that suppresses the beta-catenin transcription factor in cells without Wnt stimulation. A critical step in this regulatory pathway is to create a SCF(beta-TrCP) E3 ubiquitin ligase binding site for beta-catenin. Here we show that the SCF(beta-TrCP) binding site created by phosphorylation of beta-catenin is highly vulnerable to protein phosphatase 2A (PP2A) and must be protected by the adenomatous polyposis coli (APC) tumor suppressor protein. Specifically, phosphorylated beta-catenin associated with the wild-type APC protein is recruited to the SCF(beta-TrCP) complex, ubiquitin conjugated, and degraded. A mutation in APC that deprives this protective function exposes the N-terminal phosphorylated serine/threonine residues of beta-catenin to PP2A. Dephosphorylation at these residues by PP2A eliminates the SCF(beta-TrCP) recognition site and blocks beta-catenin ubiquitin conjugation. Thus, by acting to protect the E3 ligase binding site, APC ensures the ubiquitin conjugation of phosphorylated beta-catenin.

    Funded by: NCI NIH HHS: CA113831, CA81357

    Molecular cell 2008;32;5;652-61

  • CTLA-4 is a direct target of Wnt/beta-catenin signaling and is expressed in human melanoma tumors.

    Shah KV, Chien AJ, Yee C and Moon RT

    Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA.

    Our goal was to identify genes regulated by Wnt/beta-catenin signaling in melanoma cells, as this pathway has been implicated in melanocyte development and in melanoma biology. We therefore undertook transcriptional profiling of UACC 1273 human melanoma cells following treatment with recombinant Wnt-3a and found that cytotoxic T-lymphocyte antigen-4 (CTLA-4) was the most highly induced gene. We observed CTLA-4 expression in human epidermal melanocytes and in patient-derived primary melanoma tumors and found that Wnt/beta-catenin signaling elevates CTLA-4 expression in two cultured melanoma cell lines. CTLA-4 is likely a direct target of Wnt/beta-catenin signaling, as the beta-catenin responsiveness of a 1.7 kb region of the CTLA-4 promoter requires a T-cell factor-1/lymphoid enhancing factor-1 consensus site present at -114 to -119 bp from the transcriptional start site. These findings are the initial demonstration that CTLA-4 is a direct target of Wnt/beta-catenin signaling and the first report of its expression in primary melanoma tumors and melanocytes. Given the described role of CTLA-4 in inhibiting the immune response, these findings may shed light on the role of Wnt/beta catenin signaling in melanoma and on the mechanism of action of human anti-CTLA-4 antibody, currently in phase III clinical trials for the treatment of melanoma.

    Funded by: Howard Hughes Medical Institute; NCI NIH HHS: R21 CA091540, R21 CA091540-02

    The Journal of investigative dermatology 2008;128;12;2870-9

  • E-cadherin and beta-catenin mRNA levels throughout colon cancer progression.

    Truant SC, Gouyer VP, Leteurtre EA, Zerimech F, Huet GM and Pruvot FR

    Department of Digestive Surgery and Transplantation, University Hospitals, Lille, France. steph_truant@yahoo.fr

    Background: Although E-cadherin and beta-catenin are key regulators in tumor invasion and proliferation, few studies have been undertaken on the expression of these genes at the messenger ribonucleic acid (mRNA) level in relation to the progression of colon cancer.

    In this study, tissue samples from colectomy (n = 37) or hepatectomy (n = 23) were collected in both tumor and adjacent normal tissues. Real-time quantitative reverse transcriptase-polymerase chain reaction was used to quantify E-cadherin and beta-catenin mRNAs in reference to 18S RNA.

    Results: E-cadherin and beta-catenin levels in colon carcinomas were not statistically different compared with adjacent normal mucosa and were not correlated with tumor, nodes, and metastases (TNM) stage. Conversely, E-cadherin and beta-catenin levels were significantly higher in liver metastases than in adjacent normal tissue. Interestingly, we found that E-cadherin level in liver metastases was correlated to the TNM stage of the related primary tumor: a higher E-cadherin level was found for State I-II TNM. In addition, a high expression of E-cadherin in liver metastases was associated with a lower occurrence of extra-hepatic metastases after resection of liver metastases.

    Conclusion: Taken together, these data show that E-cadherin and beta-catenin expressions are regulated throughout colon cancer progression.

    The Journal of surgical research 2008;150;2;212-8

  • E-cadherin core fucosylation regulates nuclear beta-catenin accumulation in lung cancer cells.

    Hu P, Shi B, Geng F, Zhang C, Wu W and Wu XZ

    Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, 138 Yi Xue Yuan Road, Shanghai, 200032, China.

    E-cadherin expressed highly in 95C and lowly in 95D lung cancer cells which were from the same patient, but core-fucosylated E-cadherin highly expressed in 95D cells. Therefore, Fut8 and Fut8-RNAi constructs were transfected into 95C and 95D cells, respectively. In Fut8-transfectants, reduction of nuclear beta-catenin was noted when E-cadherin was core-fucosylated, while accumulation of nuclear beta-catenin was observed in Fut8-RNAi transfectants. In E-cadherin-negative MDA-MB-231 cells either Fut8 or Fut8-RNAi transfection couldn't affect nuclear beta-catenin. However, cotransfection of E-cadherin with Fut8 caused nuclear beta-catenin reduction. Furthermore, enhanced binding of E-cadheirn with beta-catenin as well as alpha-catenin were observed in Fut8-transfectants, and reduction of tyrosine 654 phosphorylation on beta-catenin and its transcriptional activity were also noted at the same time. Overall, the current results suggested that core-fucosylated E-cadherin regulated nuclear beta-catenin accumulation in lung cancer cells.

    Glycoconjugate journal 2008;25;9;843-50

  • Oxidative stress, telomere length and biomarkers of physical aging in a cohort aged 79 years from the 1932 Scottish Mental Survey.

    Starr JM, Shiels PG, Harris SE, Pattie A, Pearce MS, Relton CL and Deary IJ

    MRC Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Royal Victoria Hospital, Edinburgh EH4 2DN, UK. jstarr@staffmail.ed.ac.uk

    Telomere shortening is a biomarker of cellular senescence and is associated with a wide range of age-related disease. Oxidative stress is also associated with physiological aging and several age-related diseases. Non-human studies suggest that variants in oxidative stress genes may contribute to both telomere shortening and biological aging. We sought to test whether oxidative stress-related gene polymorphisms contribute to variance in both telomere length and physical biomarkers of aging in humans. Telomere lengths were calculated for 190 (82 men, 108 women) participants aged 79 years and associations with 384 SNPs, from 141 oxidative stress genes, identified 9 significant SNPS, of which those from 5 genes (GSTZ1, MSRA, NDUFA3, NDUFA8, VIM) had robust associations with physical aging biomarkers, respiratory function or grip strength. Replication of associations in a sample of 318 (120 males, 198 females) participants aged 50 years confirmed significant associations for two of the five SNPs (MSRA rs4841322, p=0.008; NDUFA8 rs6822, p=0.048) on telomere length. These data indicate that oxidative stress genes may be involved in pathways that lead to both telomere shortening and physiological aging in humans. Oxidative stress may explain, at least in part, associations between telomere shortening and physiological aging.

    Funded by: Biotechnology and Biological Sciences Research Council: S18386; Chief Scientist Office: CZB/4/505, ETM/55; Medical Research Council; Wellcome Trust

    Mechanisms of ageing and development 2008;129;12;745-51

  • Polymorphism in the IL18 gene and epithelial ovarian cancer in non-Hispanic white women.

    Palmieri RT, Wilson MA, Iversen ES, Clyde MA, Calingaert B, Moorman PG, Poole C, Anderson AR, Anderson S, Anton-Culver H, Beesley J, Hogdall E, Brewster W, Carney ME, Chen X, Chenevix-Trench G, Chang-Claude J, Cunningham JM, Dicioccio RA, Doherty JA, Easton DF, Edlund CK, Gayther SA, Gentry-Maharaj A, Goode EL, Goodman MT, Kjaer SK, Hogdall CK, Hopkins MP, Jenison EL, Blaakaer J, Lurie G, McGuire V, Menon U, Moysich KB, Ness RB, Pearce CL, Pharoah PD, Pike MC, Ramus SJ, Rossing MA, Song H, Terada KY, Vandenberg D, Vierkant RA, Wang-Gohrke S, Webb PM, Whittemore AS, Wu AH, Ziogas A, Berchuck A, Schildkraut JM, Ovarian Cancer Association Consortium, Australian Cancer Study (Ovarian Cancer Group) and Australian Ovarian Cancer Study Group

    Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.

    Over 22,000 cases of ovarian cancer were diagnosed in 2007 in the United States, but only a fraction of them can be attributed to mutations in highly penetrant genes such as BRCA1. To determine whether low-penetrance genetic variants contribute to ovarian cancer risk, we genotyped 1,536 single nucleotide polymorphisms (SNP) in several candidate gene pathways in 848 epithelial ovarian cancer cases and 798 controls in the North Carolina Ovarian Cancer Study (NCO) using a customized Illumina array. The inflammation gene interleukin-18 (IL18) showed the strongest evidence for association with epithelial ovarian cancer in a gene-by-gene analysis (P = 0.002) with a <25% chance of being a false-positive finding (q value = 0.240). Using a multivariate model search algorithm over 11 IL18 tagging SNPs, we found that the association was best modeled by rs1834481. Further, this SNP uniquely tagged a significantly associated IL18 haplotype and there was an increased risk of epithelial ovarian cancer per rs1834481 allele (odds ratio, 1.24; 95% confidence interval, 1.06-1.45). In a replication stage, 12 independent studies from the Ovarian Cancer Association Consortium (OCAC) genotyped rs1834481 in an additional 5,877 cases and 7,791 controls. The fixed effects estimate per rs1834481 allele was null (odds ratio, 0.99; 95% confidence interval, 0.94-1.05) when data from the 12 OCAC studies were combined. The effect estimate remained unchanged with the addition of the initial North Carolina Ovarian Cancer Study data. This analysis shows the importance of consortia, like the OCAC, in either confirming or refuting the validity of putative findings in studies with smaller sample sizes. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3567-72).

    Funded by: Cancer Research UK: 10118, A10119; Department of Health; NCI NIH HHS: 1-R01-CA122443, 1-R01-CA76016, CA-58860, CA14089, CA16056, CA17054, CA61132, CA63464, CA71766, K07 CA092044, N01 CN025403, N01 PC067010, N01-CN-25403, N01-CN-67001, P01 CA017054, P30 CA014089, P30 CA016056, R01 CA058598, R01 CA058860, R01 CA063464, R01 CA076016, R01 CA076016-06A1, R01 CA076016-07, R01 CA076016-08, R01 CA076016-09, R01 CA076016-10, R01 CA095023, R01 CA112523, R01 CA122443, R01-CA-58598, R01CA095023, R01CA112523, R03 CA113148, R03-CA113148, T32 CA009330, T32 CA009330-26, U01 CA058860, U01 CA063464; PHS HHS: 01 GB 9401, 050E8709

    Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology 2008;17;12;3567-72

  • Identification of beta-catenin as a novel substrate of Polo-like kinase 1.

    Arai T, Haze K, Iimura-Morita Y, Machida T, Iida M, Tanaka K and Komatani H

    Tsukuba Research Institute, Banyu Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan.

    Polo-like kinase 1 (Plk1) is a serine/threonine kinase that plays an important role in M phase progression by regulating various downstream substrates via phosphorylation. Here, we identified beta-catenin as a novel substrate of Plk1 and determined that Ser-718 is a phosphorylation site for Plk1 by using a phospho-specific antibody that cross-reacts with Plk1-dependent phosphorylation sites. Ser-718 of beta-catenin was directly phosphorylated by recombinant Plk1 in vitro, with the phosphorylation signal in cells increasing with overexpression of Plk1 and decreasing when endogenous Plk1 was depleted by small interfering RNA. The phosphorylation at Ser-718 was correlated with the cell cycle-dependent expression of Plk1 which reached a maximum in M phase. We also confirmed that there is a physical interaction between beta-catenin and Plk1 using coimmunoprecipitation and a GST pull-down assay. These results demonstrate that beta-catenin is a physiological substrate of Plk1 in cells, which may provide a novel insight into the role of beta-catenin in M phase.

    Cell cycle (Georgetown, Tex.) 2008;7;22;3556-63

  • Arsenic trioxide and 2-methoxyestradiol reduce beta-catenin accumulation after proteasome inhibition and enhance the sensitivity of myeloma cells to Bortezomib.

    Zhou L, Hou J, Fu W, Wang D, Yuan Z and Jiang H

    Department of Hematology, the Second Affiliated Hospital to the Second Military Medical University, 415 Fengyang Road, Shanghai 200003, China.

    Beta-catenin, the key protein in canonical Wingless/int (Wnt) pathway, degrades via ubiquitin-proteasome pathway. Recently, it proved important roles in the proliferation of myeloma cells. But little is known about whether cytoplasmic beta-catenin content is associated with myeloma cell's sensitivity to Bortezomib. We examined the constitutive expression of beta-catenin in five myeloma cell lines and primary cells from patients. Meanwhile, the effect of Bortezomib combined with arsenic trioxide (As(2)O(3))/2-methoxyestradiol (2ME2) on beta-catenin accumulation, myeloma cells' survival, apoptosis and their sensitivity to Bortezomib were also investigated. Our study proved that beta-catenin protein levels are negatively associated with myeloma cells' sensitivity to Bortezomib. As(2)O(3)/2ME2 can reduce cytoplasmic beta-catenin accumulation after proteasome inhibition and enhance myeloma cells' sensitivity to Bortezomib. This will preliminarily help to optimize the new therapeutic regimens for MM treatment in the future.

    Leukemia research 2008;32;11;1674-83

  • Clinical significance of levels of molecular biological markers in zones of invasive front-line of colorectal cancer.

    Delektorskaya VV, Golovkov DA and Kushlinskii NE

    N. N. Blokhin Cancer Research Center, Russian Academy of Medical Sciences, Moscow.

    The role of expression of markers (beta-catenin, matrix metalloproteinase 9, collagen IV, and laminin) in primary colorectal adenocarcinomas and their metastases in the liver and lymph nodes of patients with colorectal cancer was studied. High level of matrix metalloproteinase 9 expression in zones of invasive growth of colorectal cancer was associated with high accumulation of beta-catenin in cancer cell nuclei in the peripheral zones of 30% studied tumors. The presence of nuclear beta-catenin and high content of matrix metalloproteinase 9 in the tumor were associated with abnormal accumulation of laminin in the cytoplasm and with the absence of basal membranes containing collagen IV. These changes were characteristic of colorectal cancer with high invasive metastatic potential. It was found that beta-catenin, matrix metalloproteinase 9, laminin, and collagen IV were important markers for prediction of the clinical course of colorectal cancer. The expression of proteins associated with risk of metastases in the liver was coordinated and most pronounced in zone of invasive front-line of tumors.

    Bulletin of experimental biology and medicine 2008;146;5;616-9

  • Exploration of the APC/beta-catenin (WNT) pathway and a histologic classification system for pulmonary artery intimal sarcoma. A study of 18 cases.

    Gaumann A, Bode-Lesniewska B, Zimmermann DR, Fanburg-Smith JC, Kirkpatrick CJ, Hofstädter F, Woenckhaus M, Stoehr R, Obermann EC, Dietmaier W and Hartmann A

    Institute of Pathology, University of Regensburg, Franz-Josef Strauss Allee 11, D-93042, Regensburg, Germany. andreas.gaumann@klinik.uni-regensburg.de

    APC, a tumor suppressor gene in the Wnt pathway, stabilizes beta-catenin and controls cell growth. Mutation of APC or beta-catenin leads to nuclear accumulation of beta-catenin and transcription of cyclin D1/cyclin A. Pulmonary artery sarcoma (PAS) were studied by morphologic, immunohistochemical, and molecular genetic methods of the Wnt pathway. Eighteen cases were included: mean age 52 years, primary intraluminal location with typical clinical presentation. PAS were classified as epithelioid (n = 4) or malignant fibrous histiocytoma (MFH; spindled/pleomorphic, n = 4), myxofibrosarcoma (n = 8), and one each hemangiopericytoma-like or malignant inflammatory myofibroblastic tumor-like. The tumor cells demonstrated vimentin, focal actins, and rare focal desmin positivity. All but one were grade 2 or 3 by FNCLCC grading. Alteration in chromosome 5q21 (APC) was found in 4/14 PAS by LOH, mostly epithelioid-type; an MFH-type case demonstrated microsatellite instability (MSI) and nuclear beta-catenin. Cyclin D1 was expressed in seven tumors, all myxofibrosarcoma-type. No mutations were detected in APC or beta-catenin. In summary, PAS are predominantly intermediate grade myxofibrosarcoma in middle-aged males, and fatal in two-thirds of patients. Despite myofibroblastic phenotype, APC/beta-catenin pathway changes are rare. Cyclin D1, only expressed in the myxofibrosarcoma-type, is likely transcribed via factors other than beta-catenin.

    Virchows Archiv : an international journal of pathology 2008;453;5;473-84

  • FHL2 mediates dexamethasone-induced mesenchymal cell differentiation into osteoblasts by activating Wnt/beta-catenin signaling-dependent Runx2 expression.

    Hamidouche Z, Haÿ E, Vaudin P, Charbord P, Schüle R, Marie PJ and Fromigué O

    INSERM U606, Hopital Lariboisiere, 2 rue Ambroise Pare, 75475 Paris cedex 10, France.

    The differentiation of bone marrow mesenchymal stem cells (MSCs) into osteoblasts is a crucial step in bone formation. However, the mechanisms involved in the early stages of osteogenic differentiation are not well understood. In this study, we identified FHL2, a member of the LIM-only subclass of the LIM protein superfamily, that is up-regulated during early osteoblast differentiation induced by dexamethasone in murine and human MSCs. Gain-of-function studies showed that FHL2 promotes the expression of the osteoblast transcription factor Runx2, alkaline phosphatase, type I collagen, as well as in vitro extracellular matrix mineralization in murine and human mesenchymal cells. Knocking down FHL2 using sh-RNA reduces basal and dexamethasone-induced osteoblast marker gene expression in MSCs. We demonstrate that FHL2 interacts with beta-catenin, a key player involved in bone formation induced by Wnt signaling. FHL2-beta-catenin interaction potentiates beta-catenin nuclear translocation and TCF/LEF transcription, resulting in increased Runx2 and alkaline phosphatase expression, which was inhibited by the Wnt inhibitor DKK1. Reduction of Runx2 transcriptional activity using a mutant Runx2 results in inhibition of FHL2-induced alkaline phosphatase expression in MSCs. These findings reveal that FHL2 acts as an endogenous activator of mesenchymal cell differentiation into osteoblasts and mediates osteogenic differentiation induced by dexamethasone in MSCs through activation of Wnt/beta-catenin signaling- dependent Runx2 expression.

    FASEB journal : official publication of the Federation of American Societies for Experimental Biology 2008;22;11;3813-22

  • Integrin-linked kinase cytoplasmic and nuclear expression in laryngeal carcinomas.

    Goulioumis AK, Bravou V, Varakis J, Goumas P and Papadaki H

    Department of Anatomy, School of Medicine, University of Patras, Patras, 26500, Greece.

    Integrin-linked kinase (ILK) has been implicated in the development and progression of several human malignancies. Previous in vitro studies also implicate ILK in the activation of Akt and beta-catenin as well as in the regulation of E-cadherin expression. However, the role of ILK in human laryngeal cancer and its possible in vivo downstream effectors in the disease are currently unknown. We examined by immunohistochemistry the protein expression of ILK, phosphorylated-Akt (p-Akt), E-cadherin, and beta-catenin in 97 invasive squamous laryngeal carcinomas. Increased cytoplasmic and nuclear expression of ILK and p-Akt decreased membranous expression of E-cadherin and nuclear accumulation of beta-catenin was found in 87.6%, 85.6%, 71.1%, and 43.3% of cases, respectively. Our results suggest that ILK expression may be implicated in human laryngeal carcinoma and its localization in the nucleus possibly proposes novel nuclear functions of this molecule. In addition, enhanced ILK expression correlates with activation of Akt but not with downregulation of E-cadherin and activation of beta-catenin. Finally, in our material while activated Akt seems to characterize well-differentiated tumors, loss of E-cadherin and activation of beta-catenin correlated with high grade carcinomas.

    Virchows Archiv : an international journal of pathology 2008;453;5;511-9

  • Molecular analysis of the beta-catenin gene in patients with the Mayer-Rokitansky-Küster-Hauser syndrome.

    Drummond JB, Rezende CF, Peixoto FC, Carvalho JS, Reis FM and De Marco L

    Department of Pharmacology, Federal University of Minas Gerais, Belo Horizonte, 30310-360, Brazil. jubeaudette@hotmail.com

    Purpose: To study the beta-catenin gene in a group of Mayer-Rokitansky-Küster-Hauser patients.

    Methods: Twelve patients with the Mayer-Rokitansky-Küster-Hauser syndrome were included in this study. DNA was extracted from peripheral blood and the region codifying beta-catenin GSK-3beta phosphorylation sites on exon 3 was amplified. PCR products were purified and directly sequenced.

    Results: No mutations were found in the GSK-3beta phosphorylation sites on exon 3 of beta-catenin gene in this group of patients with the MRKH syndrome.

    Conclusions: beta-catenin gene mutations are an unlikely cause of the MRKH syndrome.

    Journal of assisted reproduction and genetics 2008;25;11-12;511-4

  • Positive KL-6 mucin expression combined with decreased membranous beta-catenin expression indicates worse prognosis in colorectal carcinoma.

    Zhang W, Tang W, Inagaki Y, Qiu M, Xu HL, Li X, Sugawara Y, Nagawa H, Nakata M and Kokudo N

    Minimally Invasive Surgery Center, Changzheng Hospital, Second Military Medical University, Shanghai, P.R. China.

    Interaction of MUC1 with beta-catenin plays a significant role in tumor progression and invasion. However, the clinical significance of coexpression of MUC1 and subcellular beta-catenin expression in colorectal carcinoma remains unclear. The present study evaluated the clinicopathological significance of their combined expression for predicting prognosis. Seventy-seven colorectal carcinomas were subjected to immunohistochemical staining with anti-MUC1 KL-6 mucin and anti-beta-catenin monoclonal antibody. Positive KL-6 mucin expression was correlated with decreased membranous beta-catenin expression (P=0.022), while no correlation was found between positive KL-6 expression and nuclear beta-catenin expression (P=0.142). Preservation of membranous beta-catenin expression was detected in 35 cases (45.5%) and decreased membranous beta-catenin expression was found in 42 cases (54.5%). Negative KL-6 expression was detected in 31 cases (41.3%) and positive expression was seen in 46 cases (59.7%). Combined positive KL-6 expression and decreased membranous beta-catenin expression was found in 30 patients (39.0%), whose survival was significantly worse than that of patients with other expression patterns for these two molecules (53.3 vs. 84.4%, P=0.005). Multivariate analysis showed that this combination was as an independent predictor of survival. We concluded that the combined pattern of positive KL-6 expression and decreased membranous beta-catenin expression by colorectal carcinoma is a useful biomarker for distinguishing a subgroup of patients with a worse prognosis.

    Oncology reports 2008;20;5;1013-9

  • Prevalence of mutations in APC, CTNNB1, and BRAF in Tunisian patients with sporadic colorectal cancer.

    Bougatef K, Ouerhani S, Moussa A, Kourda N, Coulet F, Colas C, Lahely YB, Najjar T, Ben Jilani S, Benammar-Elgaaied A, Soubrier F and Marrakchi R

    Laboratory of Human Genetics, Immunology, and Pathology, Faculty of Sciences-Tunis, University of Tunis, Campus Universitaire, El Manar I, Tunis 2092, Tunisia. karim.bougatef@fst.rnu.tn

    Sporadic colorectal tumorigenesis is caused by alterations in the Wnt (APC, CTNNB1) and Ras pathways. Our objective was to analyze the occurrence of these genetic alterations in relation to tumor and patient characteristics. The prevalence of somatic alteration in the hot-spot regions of the APC, BRAF, and CTNNB1 genes was investigated in 48 unselected and unrelated Tunisian patients with sporadic colorectal cancer, and the association between the molecular features at these genes in relation to tumor and patient characteristics (age at diagnosis, sex, tumor localization, stage, and differentiation) was analyzed. Loss of heterozygosity was observed at the APC locus in 52% of the analyzed tumors. 6 novel mutations were detected by polymerase chain reaction sequencing in the mutation cluster region of the APC gene. No mutations were observed in the CTNNB1 gene in any tumor, but 8% of tumors harbored mutation in the BRAF gene. Clinicopathological analyses showed an association between APC point mutations and the earliest occurrence of sporadic colorectal cancer. The findings confirm the heterogeneity of APC gene alteration and also reveal a particular profile of this pathology among Tunisian patients that confirms the epidemiological data for this country.

    Cancer genetics and cytogenetics 2008;187;1;12-8

  • Snail and Slug promote epithelial-mesenchymal transition through beta-catenin-T-cell factor-4-dependent expression of transforming growth factor-beta3.

    Medici D, Hay ED and Olsen BR

    Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.

    Members of the Snail family of transcription factors have been shown to induce epithelial-mesenchymal transition (EMT), a fundamental mechanism of embryogenesis and progressive disease. Here, we show that Snail and Slug promote formation of beta-catenin-T-cell factor (TCF)-4 transcription complexes that bind to the promoter of the TGF-beta3 gene to increase its transcription. Subsequent transforming growth factor (TGF)-beta3 signaling increases LEF-1 gene expression causing formation of beta-catenin-lymphoid enhancer factor (LEF)-1 complexes that initiate EMT. TGF-beta1 or TGF-beta2 stimulates this signaling mechanism by up-regulating synthesis of Snail and Slug. TGF-beta1- and TGF-beta2-induced EMT were found to be TGF-beta3 dependent, establishing essential roles for multiple TGF-beta isoforms. Finally, we determined that beta-catenin-LEF-1 complexes can promote EMT without upstream signaling pathways. These findings provide evidence for a unified signaling mechanism driven by convergence of multiple TGF-beta and TCF signaling molecules that confers loss of cell-cell adhesion and acquisition of the mesenchymal phenotype.

    Funded by: NIAMS NIH HHS: P01 AR048564, P01-AR048564; NIDCR NIH HHS: R01-DE11142

    Molecular biology of the cell 2008;19;11;4875-87

  • Specific mutations in the beta-catenin gene (CTNNB1) correlate with local recurrence in sporadic desmoid tumors.

    Lazar AJ, Tuvin D, Hajibashi S, Habeeb S, Bolshakov S, Mayordomo-Aranda E, Warneke CL, Lopez-Terrada D, Pollock RE and Lev D

    Sarcoma Research Center, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030-4001, USA.

    Desmoid fibromatosis is a rare, nonmetastatic neoplasm marked by local invasiveness and relentless recurrence. Molecular determinants of desmoid recurrence remain obscure. beta-Catenin deregulation has been commonly identified in sporadic desmoids although the incidence of CTNNB1 (the gene encoding beta-catenin) mutations is uncertain. Consequently, we evaluated the prevalence of CTNNB1 mutations in a large cohort of sporadic desmoids and examined whether mutation type was relevant to desmoid outcome. Desmoid specimens (195 tumors from 160 patients, 1985 to 2005) and control dermal scars were assembled into a clinical data-linked tissue microarray. CTNNB1 genotyping was performed on a 138-sporadic desmoid subset. Immunohistochemical scoring was performed per standard criteria and data were analyzed using Kaplan-Meier and other indicated methods. CTNNB1 mutations were observed in 117 of 138 (85%) of desmoids. Three discrete mutations in two codons of CTNNB1 exon 3 were identified: 41A (59%), 45F (33%), and 45P (8%, excluded from further analysis because of rarity). Five-year recurrence-free survival was significantly poorer in 45F-mutated desmoids (23%, P < 0.0001) versus either 41A (57%) or nonmutated tumors (65%). Nuclear beta-catenin expression was observed in 98% of specimens and intensity was inversely correlated with incidence of desmoid recurrence (P < 0.01). In conclusion, CTNNB1 mutations are highly common in desmoid tumors. Furthermore, patients harboring CTNNB1 (45F) mutations are at particular risk for recurrence and therefore may especially benefit from adjuvant therapeutic approaches.

    The American journal of pathology 2008;173;5;1518-27

  • Overall expression of beta-catenin outperforms its nuclear accumulation in predicting outcomes of colorectal cancers.

    Wanitsuwan W, Kanngurn S, Boonpipattanapong T, Sangthong R and Sangkhathat S

    Department of Surgery, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, 90110 Thailand.

    Aim: To examine the expression of beta-catenin in colorectal cancer and look for association with other clinico-pathological parameters.

    Methods: Tumor samples from 163 cases of colorectal cancer (CRC) who had undergone primary colectomy between May, 1998 and November, 2002 with complete follow-up data for either 5 years or until death were recruited for a beta-catenin immunohistochemical study. The percentage of immunoreacted tumor cells was defined as overall staining density (OSD) and percentage of cells having nuclear localization was counted as nuclear staining density (NSD). Univariate exploration used log-rank test and multivariate survival analysis used Cox's hazard regression model.

    Results: Beta-catenin immunoreactivity was detected in 161 samples (98.8%), of which 131 cases had nuclear staining. High OSD (> or = 75%), detected in 123 cases (75.5%), was significantly associated with earlier clinical staging (P < 0.01), lower nodal status (P = 0.02), non-metastatic status (P < 0.01) and better differentiation (P = 0.02). Multivariate analysis found that high OSD was independently associated with better survival [Cox's hazard ratio 0.51, 95% confidence interval (CI) 0.31-0.83]. Although high NSD (> or = 75%) was correlated with high pre-operative serum CEA (P = 0.03), well differentiation (P < 0.01), and increased staining intensity (P < 0.01), the parameter was not significantly associated with survival.

    Conclusion: Unlike previous reports, the study did not find a predictive value of nuclear beta-catenin in CRC. Instead, the overall expression of beta-catenin in CRC showed an association with better differentiation and earlier staging. Moreover, the parameter also independently predicted superior survival.

    World journal of gastroenterology 2008;14;39;6052-9

  • Polycystin-1 C-terminal tail associates with beta-catenin and inhibits canonical Wnt signaling.

    Lal M, Song X, Pluznick JL, Di Giovanni V, Merrick DM, Rosenblum ND, Chauvet V, Gottardi CJ, Pei Y and Caplan MJ

    Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA.

    Polycystin-1 (PC1), the product of the PKD1 gene mutated in the majority of autosomal dominant polycystic kidney disease (ADPKD) cases, undergoes a cleavage resulting in the intracellular release of its C-terminal tail (CTT). Here, we demonstrate that the PC1 CTT co-localizes with and binds to beta-catenin in the nucleus. This interaction requires a nuclear localization motif present in the PC1 CTT as well as the N-terminal portion of beta-catenin. The PC1 CTT inhibits the ability of both beta-catenin and Wnt ligands to activate T-cell factor (TCF)-dependent gene transcription, a major effector of the canonical Wnt signaling pathway. The PC1 CTT may produce this effect by reducing the apparent affinity of the interaction between beta-catenin and the TCF protein. DNA microarray analysis reveals that the canonical Wnt signaling pathway is activated in ADPKD patient cysts. Our results suggest a novel mechanism through which PC1 cleavage may impact upon Wnt-dependent signaling and thereby modulate both developmental processes and cystogenesis.

    Funded by: NIDDK NIH HHS: DK57328; NIGMS NIH HHS: R01 GM076561, R01 GM076561-03

    Human molecular genetics 2008;17;20;3105-17

  • Mutated in colorectal cancer, a putative tumor suppressor for serrated colorectal cancer, selectively represses beta-catenin-dependent transcription.

    Fukuyama R, Niculaita R, Ng KP, Obusez E, Sanchez J, Kalady M, Aung PP, Casey G and Sizemore N

    Department of Cancer Biology, Cleveland Clinic, Cleveland, OH 44195, USA.

    Mutated in colorectal cancer (MCC) was originally identified as a candidate gene for familial adenomatous polyposis (FAP) but further study identified adenomatous polyposis coli (APC) as responsible for FAP and the physiologic/pathologic roles of MCC remained poorly understood. Recently, MCC promoter methylation was discovered as a frequent early event in a distinct subset of precursor lesions and colorectal cancer (CRC) associated with the serrated CRC pathway. Here we provide the first evidence of the biological significance of MCC loss in CRC and the molecular pathways involved. We show MCC expression is dramatically decreased in many CRC cell lines and the distinct subset of sporadic CRC characterized by the CpG island methylator phenotype and BRAF(V600E) mutation due to promoter methylation as reported previously. Importantly, we find MCC interacts with beta-catenin and that reexpression of MCC in CRC cells specifically inhibits Wnt signaling, beta-catenin/T-cell factor/lymphoid-enhancer factor-dependent transcription and cellular proliferation even in the presence of oncogenic mutant APC. We also show that MCC is localized in the nucleus and identify two functional nuclear localization signals. Taken together, MCC is a nuclear, beta-catenin-interacting protein that can act as a potential tumor suppressor in the serrated CRC pathway by inhibiting Wnt/beta-catenin signal transduction.

    Funded by: NCI NIH HHS: CA 100748, R01 CA100748, R01 CA100748-04

    Oncogene 2008;27;46;6044-55

  • Reduced expression of E-cadherin/catenin complex in hepatocellular carcinomas.

    Zhai B, Yan HX, Liu SQ, Chen L, Wu MC and Wang HY

    Department of Ultrasonic Intervention, Second Military Medical University, Shanghai 200438, China.

    Aim: To examine the immunoreactivity of E-cadherin and four subtypes of catenin family in human hepatocellular carcinomas (HCCs) and to investigate the correlation between expression of E-cadherin/catenin complex and clinicopathologic parameters of HCC patients.

    Methods: An immunohistochemical study for E-cadherin and catenins was performed on 97 formalin-fixed, paraffin-embedded specimens of HCC.

    Results: Reduced expression of E-cadherin, alpha-, beta-, gamma-catenin and p120 was observed in 69%, 76%, 63%, 71% and 73%, respectively. Both expressions of E-cadherin and catenin components were significantly correlated with tumor grade (P = 0.000). It showed significant difference between expression of catenin members and tumor stage (P = 0.003, P = 0.017, P = 0.007 and P = 0.000, respectively). The reduced expression of E-cadherin in HCCs was significantly correlated with intrahepatic metastasis (IM) and capsular invasion (P = 0.008, P = 0.03, respectively). A close correlation was also observed between the expression of catenins and the tumor size (P = 0.002, P = 0.034, P = 0.016 and P = 0.000, respectively). In addition, the expression of each catenin was found correlated with IM (P = 0.012, P = 0.049, P = 0.026 and P = 0.014, respectively). No statistically significant difference was observed between the expression level of E-cadherin/catenin complex and lymph node permission, vascular invasion and satellite nodules. Interestingly, only expression of p120 showed correlation with AFP value (P = 0.035). The expression of E-cadherin was consistent with alpha-, beta-, gamma-catenin and p120 expression (P = 0.000). Finally, the abnormal expression of E-cadherin/catenin complex was significantly associated with patients' survival (P = 0.0253, P = 0.0052, P = 0.003, P = 0.0105 and P = 0.0016, respectively). Nevertheless, no component of E-cadherin/catenin complex was the independent prognostic factor of HCC patients.

    Conclusion: Down-regulated expressions of E-cadherin, catenins and p120 occur frequently in HCCs and contribute to the progression and development of tumor. It may be more exact and valuable to detect the co-expression of E-cadherin/catenin complex than to explore one of them in predicting tumor invasion, metastasis and patient's survival.

    World journal of gastroenterology 2008;14;37;5665-73

  • Glycogen synthase kinase-3beta regulates DeltaNp63 gene transcription through the beta-catenin signaling pathway.

    Chu WK, Dai PM, Li HL and Chen JK

    Department of Physiology, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan.

    Overexpression of DeltaNp63 has been observed in a number of human cancers, suggesting a role for DeltaNp63 in carcinogenesis. In the present study, we show that inhibition of glycogen synthase kinase-3beta (GSK-3beta) by lithium chloride (LiCl) elicited a stimulatory effect on DeltaNp63 promoter activity in HEK 293T cells. Exposure to LiCl induced DeltaNp63 promoter activation as well as DeltaNp63 protein expression in the cells. The effect of GSK-3beta on DeltaNp63 expression was further confirmed by the use of two highly specific GSK-3beta inhibitors, SB216763 and SB415286. Further study showed the presence of a putative beta-catenin responsive element (beta-catenin-RE) in the DeltaNp63 promoter region, and the stimulation of DeltaNp63 promoter activity by GSK-3beta inhibitor is markedly abolished by mutation or deletion of the putative beta-catenin-RE. Data are also presented to show that beta-catenin acts together with Lef-1 to influence DeltaNp63 promoter activity and protein expression.

    Journal of cellular biochemistry 2008;105;2;447-53

  • Regulation of Wnt/beta-catenin pathway by cPLA2alpha and PPARdelta.

    Han C, Lim K, Xu L, Li G and Wu T

    Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA. changhan@pitt.edu

    Cytosolic phospholipase A(2)alpha (cPLA(2)alpha) is a rate-limiting key enzyme that releases arachidonic acid (AA) from membrane phospholipid for the production of biologically active lipid mediators including prostaglandins, leukotrienes and platelet-activating factor. cPLA(2)alpha is translocated to nuclear envelope in response to intracellular calcium increase and the enzyme is also present inside the cell nucleus; however, the biological function of cPLA(2)alpha in the nucleus remains unknown. Here we show a novel role of cPLA(2)alpha for activation of peroxisome proliferator-activated receptor-delta (PPARdelta) and beta-catenin in the nuclei. Overexpression of cPLA(2)alpha in human cholangiocarcinoma cells induced the binding of PPARdelta to beta-catenin and increased their association with the TCF/LEF response element. These effects are inhibited by the cPLA(2)alpha siRNA and inhibitors as well as by siRNA knockdown of PPARdelta. Overexpression of PPARdelta or treatment with the selective PPARdelta ligand, GW501516, also increased beta-catenin binding to TCF/LEF response element and increased its reporter activity. Addition of AA and GW501516 to nuclear extracts induced a comparable degree of beta-catenin binding to TCF/LEF response element. Furthermore, cPLA(2)alpha protein is present in the PPARdelta and beta-catenin binding complex. Thus the close proximity between cPLA(2)alpha and PPARdelta provides a unique advantage for their efficient functional coupling in the nucleus, where AA produced by cPLA(2)alpha becomes immediately available for PPARdelta binding and subsequent beta-catenin activation. These results depict a novel interaction linking cPLA(2)alpha, PPARdelta and Wnt/beta-catenin signaling pathways and provide insight for further understanding the roles of these key molecules in human cells and diseases.

    Funded by: NCI NIH HHS: R01 CA102325, R01 CA102325-04, R01 CA106280

    Journal of cellular biochemistry 2008;105;2;534-45

  • The role of beta-catenin in chronic myeloproliferative disorders.

    Jauregui MP, Sanchez SR, Ewton AA, Rice L, Perkins SL, Dunphy CH and Chang CC

    Pathology, The Methodist Hospital and The Methodist Hospital Research Institute, Houston, TX 77030, USA.

    The goal of the current study is to evaluate the role of beta-catenin in chronic myeloproliferative disorders. Expression of beta-catenin was analyzed by immunohistochemistry in formalin-fixed decalcified bone marrow biopsy specimens from 52 chronic myeloproliferative disorder cases and 6 nonchronic myeloproliferative disorder bone marrows as controls. The frequency of moderate to strong beta-catenin staining of megakaryocytes was significantly higher in polycythemia vera cases and in essential thrombocythemia cases than in chronic myelogenous leukemia cases (polycythemia vera versus chronic myelogenous leukemia, P = .002345, Fisher exact; and essential thrombocythemia versus chronic myelogenous leukemia, P = .002288), chronic idiopathic myelofibrosis cases (polycythemia vera versus chronic idiopathic myelofibrosis, P = .006707 and essential thrombocythemia versus chronic idiopathic myelofibrosis, P = .006932) or control cases (polycythemia vera versus control, P = .010489 and essential thrombocythemia versus control, P = .0113120). The erythroid and myeloid lineages showed absent to weak beta-catenin staining in most cases. In conclusion, these results indicate that the Wnt/beta-catenin signaling pathway may have a role in megakaryocytopoiesis in polycythemia vera and essential thrombocythemia. In addition, beta-catenin may be a useful marker for differentiating polycythemia vera and essential thrombocythemia from other types of chronic myeloproliferative disorders.

    Human pathology 2008;39;10;1454-8

  • beta-catenin gene mutation in invasive ductal breast cancer.

    Kizildag S, Zengel B, Vardar E and Sakizli M

    Medical Biology and Genetics Department, Dokuz Eylul University, Faculty of Medicine, Izmir, Turkey. sefa.kizildag@deu.edu.tr

    Purpose: Aberrant accumulation of beta-catenin plays an important role in a variety of human neoplasms. In this study we analyzed the somatic mutations of the beta-catenin gene and the immunohistochemical localization of beta-catenin and cyclin D1 in invasive ductal breast cancer.

    We investigated 65 human invasive ductal breast cancer samples for somatic mutations in the exons 3, 4, 5 and 6 of beta-catenin gene (N-terminal region) by the combined use of polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP) and sequencing. Sample tissues were also analyzed using beta-catenin and cyclin D1 immunocytochemistry staining.

    Results: No beta-catenin mutation was detected in any of the tumor samples. Accumulation of aberrant beta-catenin protein in cellular compartments in the same breast cancer samples was confirmed with a related experiment by immunocytochemical methods.

    Conclusion: Our results suggest that genetic defects in beta-catenin is not common in invasive ductal breast cancers, whereas mutations in other components of the Wnt signaling pathway should be considered.

    Journal of B.U.ON. : official journal of the Balkan Union of Oncology 2008;13;4;533-6

  • Jade-1 inhibits Wnt signalling by ubiquitylating beta-catenin and mediates Wnt pathway inhibition by pVHL.

    Chitalia VC, Foy RL, Bachschmid MM, Zeng L, Panchenko MV, Zhou MI, Bharti A, Seldin DC, Lecker SH, Dominguez I and Cohen HT

    Renal Section, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA.

    The von Hippel-Lindau protein pVHL suppresses renal tumorigenesis in part by promoting the degradation of hypoxia-inducible HIF-alpha transcription factors; additional mechanisms have been proposed. pVHL also stabilizes the plant homeodomain protein Jade-1, which is a candidate renal tumour suppressor that may correlate with renal cancer risk. Here we show that Jade-1 binds the oncoprotein beta-catenin in Wnt-responsive fashion. Moreover, Jade-1 destabilizes wild-type beta-catenin but not a cancer-causing form of beta-catenin. Whereas the well-established beta-catenin E3 ubiquitin ligase component beta-TrCP ubiquitylates only phosphorylated beta-catenin, Jade-1 ubiquitylates both phosphorylated and non-phosphorylated beta-catenin and therefore regulates canonical Wnt signalling in both Wnt-off and Wnt-on phases. Thus, the different characteristics of beta-TrCP and Jade-1 may ensure optimal Wnt pathway regulation. Furthermore, pVHL downregulates beta-catenin in a Jade-1-dependent manner and inhibits Wnt signalling, supporting a role for Jade-1 and Wnt signalling in renal tumorigenesis. The pVHL tumour suppressor and the Wnt tumorigenesis pathway are therefore directly linked through Jade-1.

    Funded by: NCI NIH HHS: R01 CA071796, R01 CA071796-11, R01 CA079830, R01 CA079830-08, R01 CA71796, R01 CA79830; NIDDK NIH HHS: R01 DK067569, R01 DK067569-05, R01 DK67569, T32 DK007053-32, T32 DK07053

    Nature cell biology 2008;10;10;1208-16

  • Mutational analysis of Wnt signaling molecules in ameloblastoma with aberrant nuclear expression of beta-catenin.

    Tanahashi J, Daa T, Yada N, Kashima K, Kondoh Y and Yokoyama S

    Department of Pathology, Faculty of Medicine, Oita University, Yufu-shi, Japan.

    Background: To clarify the genetic background of ameloblastoma, expression of beta-catenin, and mutational status of genes involved in Wnt signaling pathway were investigated.

    Methods: We analyzed beta-catenin and cyclin D1 in 18 cases of ameloblastoma by immunohistochemical staining, and searched for mutations in CTNNB1 (gene for beta-catenin), APC, AXIN1, and AXIN2 by polymerase chain reaction (PCR) and direct sequencing method.

    Result: We detected membranous and occasionally cytoplasmic expression of beta-catenin in 16 of 18 cases (89%), and nuclear expression of beta-catenin principally in the peripheral columnar cells in 11 of 18 cases (61%). In nine of the 18 cases (50%), we detected the expression of cyclin D1 principally in the peripheral columnar cells. However, there was no correlation between nuclear expressions of beta-catenin and cyclin D1. No missense mutations were found in CTNNB1, APC, AXIN1, and AXIN2 in all cases except for silent mutation and already-known single nucleotide polymorphism.

    Conclusion: Mutations in CTNNB1, APC, AXIN1, and AXIN2 are not implicated in nuclear accumulation of beta-catenin, and that the expression of cyclin D1 is accelerated independently of beta-catenin in ameloblastomas. Other Wnt signaling members or alternative pathways involved in the degradation of beta-catenin should be subject of further investigation.

    Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology 2008;37;9;565-70

  • Pathway-based evaluation of 380 candidate genes and lung cancer susceptibility suggests the importance of the cell cycle pathway.

    Hosgood HD, Menashe I, Shen M, Yeager M, Yuenger J, Rajaraman P, He X, Chatterjee N, Caporaso NE, Zhu Y, Chanock SJ, Zheng T and Lan Q

    Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. hosgoodd@mail.nih.gov

    Common genetic variation may play an important role in altering lung cancer risk. We conducted a pathway-based candidate gene evaluation to identify genetic variations that may be associated with lung cancer in a population-based case-control study in Xuan Wei, China (122 cases and 111 controls). A total of 1260 single-nucleotide polymorphisms (SNPs) in 380 candidate genes for lung cancer were successfully genotyped and assigned to one of 10 pathways based on gene ontology. Logistic regression was used to assess the marginal effect of each SNP on lung cancer susceptibility. The minP test was used to identify statistically significant associations at the gene level. Important pathways were identified using a test of proportions and the rank truncated product methods. The cell cycle pathway was found as the most important pathway (P = 0.044) with four genes significantly associated with lung cancer (PLA2G6 minP = 0.001, CCNA2 minP = 0.006, GSK3 beta minP = 0.007 and EGF minP = 0.013), after adjusting for multiple comparisons. Interestingly, most cell cycle genes that were associated with lung cancer in this analysis were concentrated in the AKT signaling pathway, which is essential for regulation of cell cycle progression and cellular survival, and may be important in lung cancer etiology in Xuan Wei. These results should be viewed as exploratory until they are replicated in a larger study.

    Funded by: Intramural NIH HHS; NCI NIH HHS: TU2 CA105666

    Carcinogenesis 2008;29;10;1938-43

  • Relation among p130Cas, E-cadherin and beta-catenin expression, clinicopathologic significance and prognosis in human hepatocellular carcinoma.

    Guo C, Liu QG, Yang W, Zhang ZL and Yao YM

    Department of Hepatobiliary Surgery, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China. guocheng121@hotmail.com.

    Background: p130Cas (p130Crk-associated substance) is a junction protein that is important to the adhesion between cytoskeleton and extracellular matrix. Also, the adhesion molecules E-cadherin and beta-catenin play important roles in the invasiveness of carcinoma. This study was undertaken to investigate the effects of p130Cas, E-cadherin and beta-catenin on the invasion, metastasis and prognosis of hepatocellular carcinoma (HCC).

    Methods: Immunohistochemistry was used to evaluate the expression of p130Cas, E-cadherin, and beta-catenin in 40 patients with HCC. All patients were followed up postoperatively, and the relationship between expression and clinicopathological prognostic parameters was analyzed.

    Results: The positive expression rates of p130Cas and E-cadherin in HCC tissue (n=40) were 62.50% and 55.00%, but in normal liver tissue 10%, and 100%, respectively (P<0.05). The abnormal expression rate of beta-catenin in HCC tissue was 70%, while in normal liver tissue it was 13.33% (P<0.05). The positive rate of p130Cas was correlated with lymph node invasion, pathological stage, TNM stage, and a worse prognosis, but not with gender, age, HBV infection, hepatic cirrhosis, alpha-fetoprotein (AFP) level before operation, and tumor diameter. Similarly, the expression of E-cadherin and beta-catenin was correlated with lymph node invasion, pathological stage, TNM stage, and worse prognosis, but not with gender, age, HBV infection, hepatic cirrhosis, AFP level before operation, and tumor size. Correlations were found between p130Cas and abnormal E-cadherin/beta-catenin expression (P<0.001 and <0.05, respectively).

    Conclusions: In HCC, there is a negative correlation between the positive expression of p130Cas and the normal expression of the adhesion molecules E-cadherin/beta-catenin, and p130Cas plays important roles in the invasion, metastasis and prognosis of HCC. p130Cas may be involved in alterating the structure and function of E-cadherin/beta-catenin, by regulating tyrosine phosphorylation via the p130Cas-Src signal pathway.

    Hepatobiliary & pancreatic diseases international : HBPD INT 2008;7;5;490-6

  • Wnt/beta-catenin and 3',5'-cyclic adenosine 5'-monophosphate/protein kinase A signaling pathways alterations and somatic beta-catenin gene mutations in the progression of adrenocortical tumors.

    Gaujoux S, Tissier F, Groussin L, Libé R, Ragazzon B, Launay P, Audebourg A, Dousset B, Bertagna X and Bertherat J

    Service des Maladies Endocriniennes et Métaboliques, Hôpital Cochin, 75014 Paris, France.

    Background: The Wnt/beta-catenin and cAMP signaling pathways play an important role in adrenal cortex tumorigenesis. Somatic activating mutations of the beta-catenin gene (CTNNB1) are the most frequent genetic defects identified both in adrenocortical adenomas (ACAs) and adrenocortical cancers (ACCs). PRKAR1A mutations leading to cAMP pathway dysregulation are observed in primary pigmented nodular adrenocortical diseases (PPNADs) and some sporadic ACAs.

    Objective: The objective of the investigation was to study Wnt/beta-catenin dysregulation in adrenocortical tumors (ACTs) with cAMP pathway genetic alteration and search for secondary CTNNB1 somatic mutations in heterogeneous tumors.

    Nine PPNADs, including five with macronodules, three ACAs with PRKAR1A somatic mutations, and one heterogeneous tumor with ACC developed within an ACA, were studied by immunohistochemistry and DNA sequencing.

    Results: beta-Catenin accumulation was observed in all PPNADs, ACAs with PRKAR1A mutations, and the ACC component of the heterogeneous tumor. CTNNB1 somatic activating mutations were found in the macronodule of two of the five macronodular PPNADs, in one ACA with a PRKAR1A somatic mutation, and in the malignant part of the heterogeneous ACT.

    Conclusions: The Wnt/beta-catenin pathway is activated in PPNADs and ACAs with PRKAR1A mutations, suggesting a cross talk between the cAMP and Wnt/beta-catenin pathways in ACT development. In addition, the occurrence as an additional hit of a CTNNB1 somatic mutation is associated with larger or more aggressive ACTs. This underlines the importance of the Wnt/beta-catenin pathway in adrenal cortex tumorigenesis and the importance of genetic accumulation in the progression of ACTs.

    The Journal of clinical endocrinology and metabolism 2008;93;10;4135-40

  • Slit-2 induces a tumor-suppressive effect by regulating beta-catenin in breast cancer cells.

    Prasad A, Paruchuri V, Preet A, Latif F and Ganju RK

    Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA. abailugu@bidmc.harvard.edu

    SLIT-2 is considered as a candidate tumor suppressor gene, because it is frequently inactivated in various cancers due to hypermethylation of its promoter region and allelic loss. However, the exact mechanism of its tumor-suppressive effect has not been elucidated. Here, we observed that Slit-2-overexpressing breast cancer cells exhibited decreased proliferation and migration capabilities compared with control cells under in vitro conditions. These results were confirmed in vivo in mouse model systems. Mice injected with MCF-7/Slit-2 cells showed a 60-70% reduction in tumor size compared with mice injected with MCF-7/VC cells both in the absence and presence of estrogen. Upon further elucidation, we observed that Slit-2 mediates the tumor-suppressive effect via a coordinated regulation of the beta-catenin and PI3K signaling pathways and by enhancing beta-catenin/E-cadherin-mediated cell-cell adhesion. Our study for the first time reveals that Slit-2-overexpressing breast cancer cells exhibit tumor suppressor capabilities through the novel mechanism of beta-catenin modulation.

    Funded by: NCI NIH HHS: CA109527

    The Journal of biological chemistry 2008;283;39;26624-33

  • Silencing mediator for retinoid and thyroid hormone receptor and nuclear receptor corepressor attenuate transcriptional activation by the beta-catenin-TCF4 complex.

    Song LN and Gelmann EP

    Department of Medicine, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York 10032, USA.

    beta-Catenin is a multifunctional mediator of cellular signaling and an oncogene. Nuclear beta-catenin, when complexed with members of the T-cell factor (TCF)/leukocyte enhancer factor family of DNA-binding proteins, mediates transcriptional activation important for embryonic development and adult cell homeostasis. Deregulation of intracellular levels of beta-catenin is an early event in the development of a variety of cancers. We observed that the proteins silencing mediator for retinoid and thyroid hormone receptor (SMRT) and the nuclear receptor corepressor (NCoR) are negative regulators of transcription induced by the beta-catenin-TCF4 complex. Overexpression of SMRT and NCoR attenuated the transcription of beta-catenin-TCF4-specific reporter gene and of CCND1, an endogenous beta-catenin target gene. Knockdown of endogenous SMRT or NCoR by short interfering RNA augmented the beta-catenin-TCF4-mediated reporter gene expression. Glutathione S-transferase pulldown experiments showed there was a direct physical association of SMRT and NCoR with both beta-catenin and TCF4. DNA-protein interaction studies revealed that the interactions between either SMRT or NCoR and beta-catenin or TCF4 occurred at the promoter regions of CCND1 and other target genes. These findings demonstrate an important role for corepressors SMRT and NCoR in the regulation of beta-catenin-TCF4-mediated gene transcription.

    Funded by: NCI NIH HHS: CA96854

    The Journal of biological chemistry 2008;283;38;25988-99

  • O-GlcNAc-glycosylation of beta-catenin regulates its nuclear localization and transcriptional activity.

    Sayat R, Leber B, Grubac V, Wiltshire L and Persad S

    Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada L8N 3Z5.

    Beta-catenin plays a role in intracellular adhesion and regulating gene expression. The latter role is associated with its oncogenic properties. Phosphorylation of beta-catenin controls its intracellular expression but mechanism/s that regulates the nuclear localization of beta-catenin is unknown. We demonstrate that O-GlcNAc glycosylation (O-GlcNAcylation) of beta-catenin negatively regulates its levels in the nucleus. We show that normal prostate cells (PNT1A) have significantly higher amounts of O-GlcNAcylated beta-catenin compared to prostate cancer (CaP) cells. The total nuclear levels of beta-catenin are higher in the CaP cells than PNT1A but only a minimal fraction of the nuclear beta-catenin in the CaP cells are O-GlcNAcylated. Increasing the levels of O-GlcNAcylated beta-catenin in the CaP cells with PUGNAc (O- (2-acetamido-2-deoxy-d-gluco-pyranosylidene) amino-N-phenylcarbamate) treatment is associated with a progressive decrease in the levels of beta-catenin in the nucleus. TOPFlash reporter assay and mRNA expressions of beta-catenin's target genes indicate that O-GlcNAcylation of beta-catenin results in a decrease in its transcriptional activity. We define a novel modification of beta-catenin that regulates its nuclear localization and transcriptional function.

    Experimental cell research 2008;314;15;2774-87

  • RUNX3 attenuates beta-catenin/T cell factors in intestinal tumorigenesis.

    Ito K, Lim AC, Salto-Tellez M, Motoda L, Osato M, Chuang LS, Lee CW, Voon DC, Koo JK, Wang H, Fukamachi H and Ito Y

    Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore 138673.

    In intestinal epithelial cells, inactivation of APC, a key regulator of the Wnt pathway, activates beta-catenin to initiate tumorigenesis. However, other alterations may be involved in intestinal tumorigenesis. Here we found that RUNX3, a gastric tumor suppressor, forms a ternary complex with beta-catenin/TCF4 and attenuates Wnt signaling activity. A significant fraction of human sporadic colorectal adenomas and Runx3(+/-) mouse intestinal adenomas showed inactivation of RUNX3 without apparent beta-catenin accumulation, indicating that RUNX3 inactivation independently induces intestinal adenomas. In human colon cancers, RUNX3 is frequently inactivated with concomitant beta-catenin accumulation, suggesting that adenomas induced by inactivation of RUNX3 may progress to malignancy. Taken together, these data demonstrate that RUNX3 functions as a tumor suppressor by attenuating Wnt signaling.

    Cancer cell 2008;14;3;226-37

  • Clinical relevance of mutations in the Wilms tumor suppressor 1 gene WT1 and the cadherin-associated protein beta1 gene CTNNB1 for patients with Wilms tumors: results of long-term surveillance of 71 patients from International Society of Pediatric Oncology Study 9/Society for Pediatric Oncology.

    Royer-Pokora B, Weirich A, Schumacher V, Uschkereit C, Beier M, Leuschner I, Graf N, Autschbach F, Schneider D and von Harrach M

    Institute of Human Genetics and Anthropology, Heinrich-Heine University of Duesseldorf, Duesseldorf, Germany. royer@uni-duesseldorf.de

    Background: Mutations in the Wilms tumor (WT) suppressor 1 gene (WT1) and the cadherin-associated protein beta1 gene (CTNNB1) are found predominantly in stromal type WT, defining a genetic subgroup. The clinical relevance of these mutations remains to be determined.

    Methods: A long-term follow-up study was performed for 71 patients (International Society of Pediatric Oncology Study 9/Society for Pediatric Oncology; n = 77 tumors) with known molecular genetic status. Eight patients had bilateral disease, including 2 patients with a WT in both kidneys and 5 patients with a WT in 1 kidney and nephrogenic rests (NRs) in the other kidney. The response to preoperative chemotherapy, relapses, metastases, metachronous tumor development, and deaths were evaluated with a median follow-up of 12 years and 4 months.

    Results: Nineteen patients (n = 24 tumors) had WT1 mutations, and 16 were constitutional mutations. Three patients with germline mutations had second tumor events: Two patients developed a WT in the kidney with NRs 3 years and 11 years after the first tumor; and 1 patient developed second tumors after 2 years, 1 in the kidney with a previous WT and 1 in the kidney with a previous NR. Eighteen of the WT1 mutant tumors were analyzed for CTNNB1 mutations, and all had mutations. A poor volumetric response (progression and <50% reduction) was observed in all patients who had tumors with a WT1 mutation and in 23 of 52 nonmutant tumors.

    Conclusions: Patients with WT1 germline mutations had an increased risk for bilateral disease and second tumor events. Therefore, the authors concluded that tumor surveillance until adulthood should be considered. Although tumors with both WT1 and CTNNB1 mutations had a poor volumetric response, there was no significant difference in overall survival in this cohort of patients with and without WT1 mutations.

    Cancer 2008;113;5;1080-9

  • Nuclear targeting of beta-catenin and p120ctn during thrombin-induced endothelial barrier dysfunction.

    Beckers CM, García-Vallejo JJ, van Hinsbergh VW and van Nieuw Amerongen GP

    Department for Physiology, VU University Medical Center, Institute for Cardiovascular Research, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.

    Aims: Cytosolic and nuclear localization of beta-catenin was observed in leaky vessels and in tumours. Several lines of evidence indicate that nuclear beta-catenin facilitates angiogenesis. We hypothesized that nuclear beta-catenin liberated from endothelial junctional complexes marks the transition from hyperpermeability to angiogenesis. The aim of this study was, therefore, to investigate the fate of beta-catenin and the related catenin p120catenin (p120ctn), during disruption of the endothelial barrier function in human umbilical vein endothelial cells (ECs).

    The hyperpermeability-inducer thrombin caused a Rho kinase-dependent redistribution of beta-catenin from the membrane to the cytosol as evidenced by the western blot analysis of membrane and cytosol fractions and by immunohistochemistry. Glycogen synthase kinase 3beta, which phosphorylates cytosolic beta-catenin and thereby facilitates its proteasomal degradation, was inhibited by thrombin. The analysis of nuclear extracts demonstrated a thrombin-induced nuclear accumulation of beta-catenin as well as p120ctn. Thrombin stimulation activated beta-catenin-mediated transcriptional activity as evidenced by reporter assays. Finally, real-time-PCR revealed increased mRNA levels of several beta-catenin target genes.

    Conclusion: Thrombin induced a cytosolic stabilization of membrane-liberated beta-catenin, which, together with p120ctn, subsequently translocated to the nucleus where it induces several beta-catenin target genes. This supports the suggestion that membrane-liberated beta-catenin and p120ctn contribute to angiogenic responses of ECs following episodes of vascular leakage.

    Cardiovascular research 2008;79;4;679-88

  • [The specific features of the expression of E-cadherin and beta-catenin in adenomyosis].

    Gorbacheva IuV, Romadanova IuA, Solomakhina MA, Popova OP and Voloshchuk IN

    The expression of E-cadherin and beta-catenin in the eutopic and ectopic endometrium was studied in 40 patients with adenomyosis and 12 without this condition, by using an immunohistochemical test and enzyme immunoassay. There was increased expression of E-cadherin and beta-catenin in the eutopic and ectopic endometrium in adenomyosis. The cytoplasmic expression of beta-catenin was also revealed in the smooth muscle cells surrounding the foci of adenomyosis. The E-cadherin concentration measured by enzyme immunoassay was significantly higher in the endometrium and myometrium of patients with adenomyosis than in the controls. There was a higher expression of this protein with a longer duration of the disease. Thus, the formation of ectopic foci in adenomyosis may be argued to be unassociated with the decreased adhesion of epithelial cells. On the contrary, the authors documented the enhanced adhesion of epithelial cells in the ectopic foci, which was likely to be adaptive due to the altered microcirculation.

    Arkhiv patologii 2008;70;5;12-6

  • Beta-catenin expression and mutation in adult and pediatric Wilms' tumors.

    Su MC, Huang WC and Lien HC

    Department of Pathology, Min-Sheng General Hospital, Taoyuan, Taiwan.

    Wilms' tumor is the most common pediatric renal neoplasm, but its occurrence in adults is very rare. In contrast to pediatric Wilms' tumor (PWT), very little is known about the pathogenesis of adult Wilms' tumor (AWT). Despite there currently being no morphological difference between AWT and PWT, a cytogenetic study has suggested that the pathogenesis of AWT might be different from that of PWT. Although dysregulation of the Wnt pathway has been implicated in PWT, its role in AWT has never been investigated. To investigate the role of dysregulation of the Wnt pathway in AWT, tumor samples from 4 AWTs and 19 PWTs were surveyed for subcellular localization of beta-catenin by immunohistochemistry and potential mutation of the beta-catenin gene by sequencing. Nuclear translocation of beta-catenin was found in one out of four cases of AWT, but none of them carried mutation of the beta-catenin gene. By comparison, nuclear translocation for beta-catenin and mutation of the beta-catenin gene were present in 53% (10/19) and 15.8% (3/19) of PWTs, respectively. Of the three mutations identified, we found a novel mutation combining a silent mutation (TCT to TCC, Ser37Ser) and an in-frame six-base-pair deletion (del GGTGCC, del Gly38Ala39). This report suggests that dysregulation of the Wnt pathway might also play a role in the pathogenesis of AWT.

    APMIS : acta pathologica, microbiologica, et immunologica Scandinavica 2008;116;9;771-8

  • Detection of somatic beta-catenin mutations in primary pigmented nodular adrenocortical disease (PPNAD).

    Tadjine M, Lampron A, Ouadi L, Horvath A, Stratakis CA and Bourdeau I

    Division of Endocrinology, Department of Medicine, Centre hospitalier de l'Université de Montréal (CHUM) Hôtel-Dieu, Montreal, QC, Canada.

    Background: Primary pigmented nodular adrenocortical disease (PPNAD) leads to Cushing syndrome (CS) and is often associated with Carney complex (CNC). Genetic alterations of the type 1-alpha regulatory subunit of cAMP-dependent protein kinase A (PRKAR1A) and phosphodiesterase 11A4 (PDE11A) genes have been found in PPNAD. Recent studies have demonstrated that beta-catenin mutations are frequent in adrenocortical adenomas and carcinomas and that the Wnt-signalling pathway is involved in PPNAD tumorigenesis. We hypothesized that adrenocortical adenomas that form in the context of PPNAD may harbour beta-catenin mutations.

    Methods: We studied 18 patients with CS secondary to PPNAD who were screened for germline PRKAR1A and PDE11A mutations. Tumor DNA was extracted from pigmented adrenocortical adenoma and nodular adrenal hyperplasia. Mutation analysis of exons 3 and 5 of beta-catenin was performed using polymerase chain reaction and direct sequencing. Sections from formalin-fixed, paraffin-embedded tumour samples were studied by immunohistochemistry with an antibody against beta-catenin.

    Results: Nine patients were carrying germline PRKAR1A mutations and one patient had a PDE11A mutation. We found somatic beta-catenin mutations in 2 of 18 patients (11%). In both cases, the mutations occurred in relatively large adenomas that had formed in the background of PPNAD. Tumor DNA analysis revealed a heterozygous ACC-to-GCC missense mutation in codon 41 (T41A) and a TCT-to-CCT missense mutation in codon 45 (S45P) of exon 3 of the beta-catenin gene that was confirmed at the cDNA level. There were no alterations in the DNA of PPNAD-adjacent tissues and lymphocytes from the patients, indicating somatic events. Immunohistochemistry showed nuclear accumulation of beta-catenin in more than 90% of cells in adenomatous tissue whereas no nuclear immunoreactivity was detected in adjacent PPNAD nodular cells. Nuclear translocation of beta-catenin protein in the PPNAD adenoma suggests activation of the Wnt-beta-catenin pathway in PPNAD.

    Conclusions: We report, for the first time, beta-catenin mutations in adenomas associated with PPNAD, further implicating Wnt-beta-catenin signalling in tumorigenesis linked to bilateral adrenal hyperplasias.

    Funded by: NICHD NIH HHS: ZIA HD000642-13

    Clinical endocrinology 2008;69;3;367-73

  • Smad7 stabilizes beta-catenin binding to E-cadherin complex and promotes cell-cell adhesion.

    Tang Y, Liu Z, Zhao L, Clemens TL and Cao X

    Department of Pathology, University of Alabama at Birmingham, 1670 University Boulevard, Birmingham, AL 35294, USA.

    Beta-catenin functions both as an adherens junction adhesion protein and as an essential mediator of the canonical Wnt signaling pathway. Wnts stabilize beta-catenin and promote its accumulation in the nucleus, where it regulates transcription of the target genes. Here we show that Smad7 promotes cell-cell adhesion by stabilizing beta-catenin and consequently increases the beta-catenin-E-cadherin complex level at the plasma membrane. A Smad7-Axin interaction disassociates GSK-3beta and beta-catenin from Axin, as well as inhibits the recruitment of Smurf2, an E3 ligase, to beta-catenin, thus protecting beta-catenin from phosphorylation and degradation. Smad7 increases the stabilized beta-catenin to form a complex with E-cadherin and stabilizes the E-cadherin-beta-catenin complex. Thereby, rather than being translocated to the nucleus for regulating the target gene transcription, Smad7-stabilized-beta-catenin is shunted to the E-cadherin complex to modulate cell-cell adhesion.

    Funded by: NIDDK NIH HHS: DK 57501

    The Journal of biological chemistry 2008;283;35;23956-63

  • Prognostic significance of BMP and activin membrane-bound inhibitor in colorectal cancer.

    Togo N, Ohwada S, Sakurai S, Toya H, Sakamoto I, Yamada T, Nakano T, Muroya K, Takeyoshi I, Nakajima T, Sekiya T, Yamazumi Y, Nakamura T and Akiyama T

    Department of Surgery, Graduate School of Medicine, Gunma University, 3-39-22 Showa-Machi, Maebashi, Gunma, Japan.

    Aim: To investigate the clinical significance of BMP and activin membrane-bound inhibitor (BAMBI) which is a pseudoreceptor of transforming growth factor-beta (TGF-beta) type I receptors and acts as a negative regulator of TGF-beta signaling and expression aberrantly elevated in colorectal cancers (CRCs). We studied BAMBI expression in CRCs.

    Methods: We studied BAMBI expression in 183 surgically resected CRCs by immunochemical and immunoblotting analyses using a generated monoclonal anti-BAMBI antibody. Commercially available anti-beta-catenin and anti-p53 antibodies were also applied for immunochemical analyses as a comparison control.

    Results: Immunohistochemical analysis revealed that BAMBI expression was observed in 148 (80.8%), and strong BAMBI expression was observed in 46% of the CRCs. Strong BAMBI expression was positively correlated with histological type, depth of invasion, lymph node metastases, and tumor node metastasis (TNM) stage (P < 0.05). Clear associations were found between BAMBI and beta-catenin (P = 0.035) and p53 (P = 0.049) expression. In curatively resected CRC, 5-year recurrence-free survival was 51.9% (P = 0.037) for strong BAMBI expression compared to 79.8% for weak BAMBI expression. In the Cox's multivariate analysis, lymph node metastases (RR 6.685; P < 0.001) and depth of invasion (RR 14.0; P = 0.013) were significant indicators for recurrence, and strong BAMBI expression (RR 2.26; P = 0.057) tended to be significant.

    Conclusion: BAMBI was linked to a potentially aggressive tumor phenotype and predicted tumor recurrence and cancer-related death in CRC. BAMBI expression might be applicable in the routine clinical setting of CRC.

    World journal of gastroenterology 2008;14;31;4880-8

  • Localized decrease of beta-catenin contributes to the differentiation of human embryonic stem cells.

    Lam H, Patel S, Wong J, Chu J, Lau A, Li A and Li S

    Department of Bioengineering, University of California, Berkeley, B108A Stanley Hall, Berkeley, CA 94720-1762, USA.

    Human embryonic stem cells (hESC) are pluripotent, and can be directed to differentiate into different cell types for therapeutic applications. To expand hESCs, it is desirable to maintain hESC growth without differentiation. As hESC colonies grow, differentiated cells are often found at the periphery of the colonies, but the underlying mechanism is not well understood. Here, we utilized micropatterning techniques to pattern circular islands or strips of matrix proteins, and examined the spatial pattern of hESC renewal and differentiation. We found that micropatterned matrix restricted hESC differentiation at colony periphery but allowed hESC growth into multiple layers in the central region, which decreased hESC proliferation and induced hESC differentiation. In undifferentiated hESCs, beta-catenin primarily localized at cell-cell junctions but not in the nucleus. The amount of beta-catenin in differentiating hESCs at the periphery of colonies or in multiple layers decreased significantly at cell-cell junctions. Consistently, knocking down beta-catenin decreased Oct-4 expression in hESCs. These results indicate that localized decrease of beta-catenin contributes to the spatial pattern of differentiation in hESC colonies.

    Biochemical and biophysical research communications 2008;372;4;601-6

  • Alterations in beta-catenin expression and localization in prostate cancer.

    Whitaker HC, Girling J, Warren AY, Leung H, Mills IG and Neal DE

    Uro-Oncology Research Group, Cancer Research UK Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge, UK. hayley.whitaker@cancer.org.uk

    Background: Wnt signaling is thought to be important in prostate cancer, in part because proteins such as beta-catenin can also affect androgen receptor signaling. beta-Catenin forms a cell adhesion complex with E-cadherin raising the possibility that loss of expression or a change in beta-catenin distribution in the cell could also alter downstream signaling, decreased inter-cellular adhesion and the promotion of metastasis. A number of studies have reported the altered expression and/or localization of beta-catenin as a biomarker in prostate cancer.

    Methods: Tissue microarrays comprised of BPH and low, moderate and high-grade prostate cancer (n=77) were assessed for beta-catenin expression and distribution using immunohistochemistry. Staining was also performed on a tissue microarray containing tissue from patients before and after hormone manipulation. The effects of fixation and different antibodies was assessed on fixed LNCaP cell pellets and small prostate tissue microarrays.

    Results: We have observed increased beta-catenin expression in only high Gleason score (>7) prostate cancer. A nuclear re-distribution of beta-catenin has previously been reported. We noted nuclear beta-catenin in benign prostatic hyperplasia and a gradual loss in nuclear distribution with increasing Gleason grade. We found no evidence for an alteration in beta-catenin expression or re-distribution with hormone ablation. Altered fixation, antibodies and antibody concentration did affect the intensity and specificity of staining.

    Conclusions: A loss of nuclear beta-catenin is the most consistent feature in prostate cancer rather than absolute levels of expression. We also suggest that variation in immunohistochemical protocols may explain variations in the reported literature.

    Funded by: Cancer Research UK; Medical Research Council: G0500966

    The Prostate 2008;68;11;1196-205

  • OPG is regulated by beta-catenin and mediates resistance to TRAIL-induced apoptosis in colon cancer.

    De Toni EN, Thieme SE, Herbst A, Behrens A, Stieber P, Jung A, Blum H, Göke B and Kolligs FT

    Department of Medicine II, University of Munich, Munich, Germany.

    Purpose: Resistance to apoptosis is a hallmark of cancer and correlates with aggressiveness of tumors and poor prognosis. The Wnt/beta-catenin pathway plays a pivotal role in the genesis of colorectal cancer by mechanisms not fully elucidated yet. Previous studies have linked regulation of osteoprotegerin (OPG) in bone to Wnt/beta-catenin signaling. As OPG also serves as a decoy receptor for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), we hypothesized that OPG might play a role in mediating resistance to apoptosis in colorectal cancer cells.

    Expression analysis and functional studies in human colorectal cancer cell lines and determination of expression in primary tumors and sera from patients with colorectal cancer.

    Results: We found production of OPG in colorectal cancer cells to be regulated by beta-catenin/Tcf-4. Addition of exogenous OPG to colorectal cancer cells caused resistance to TRAIL. Similarly, accumulation of OPG in medium of cultivated cells caused resistance to TRAIL, and this could be reverted by removal of OPG. Furthermore, OPG levels were significantly increased in serum of patients with advanced disease.

    Conclusions: We conclude that the Wnt/beta-catenin pathway contributes to carcinogenesis and cancer cell survival by driving expression of OPG. Expression of the survival factor OPG might provide colorectal cancer cells with an essential growth advantage and contribute to cell invasion and metastasis. Inhibition of OPG expression might offer a new therapeutic approach for the treatment of patients with colorectal tumors overexpressing OPG and make these tumors sensitive to TRAIL-induced apoptosis.

    Clinical cancer research : an official journal of the American Association for Cancer Research 2008;14;15;4713-8

  • Beta-catenin in the race to fracture repair: in it to Wnt.

    Silkstone D, Hong H and Alman BA

    University of Toronto, Toronto, ON, Canada.

    The Wnt/beta-catenin pathway regulates multiple biological events during embryonic development, including bone formation. Fracture repair recapitulates some of the processes of normal bone development, such as the formation of bone from a cartilaginous template, and many cell-signaling pathways that underlie bone development are activated during the repair process. The Wnt/beta-catenin signaling pathway is activated during fracture repair, and dysregulation of this pathway alters the normal bone-healing response. In early pluripotent mesenchymal stem cells, Wnt/beta-catenin signaling needs to be precisely regulated to facilitate the differentiation of osteoblasts; by contrast, beta-catenin is not needed for chondrocyte differentiation. Once mesenchymal stem cells are committed to the osteoblast lineage, activation of Wnt/beta-catenin signaling enhances bone formation. This activity suggests that the Wnt/beta-catenin pathway is a therapeutic target during bone repair. Indeed, treatments that activate Wnt/beta-catenin signaling, such as lithium, increase bone density and also enhance healing.

    Nature clinical practice. Rheumatology 2008;4;8;413-9

  • Clinicopathological and molecular analysis of endometrial carcinoma associated with tamoxifen.

    Turbiner J, Moreno-Bueno G, Dahiya S, Sánchez-Estevez C, Hardisson D, Prat J, Oliva E and Palacios J

    Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA. jturbiner@partners.org

    Use of tamoxifen for treatment and prevention of breast cancer is becoming increasingly common. Tamoxifen has been associated with increased risk of endometrial carcinoma, although the exact mechanism of action is unknown. The aim of our study was to seek a possible correlation between endometrial carcinoma, tamoxifen exposure and MSI, PTEN, beta-catenin and K-ras abnormalities. A group of 18 patients with endometrial carcinoma following treatment with tamoxifen were selected. A control group included 15 patients with endometrial carcinoma and associated ovarian hyperthecosis and one patient with endometrial carcinoma and adult granulosa cell tumor of the ovary, chosen because both conditions are associated with increased production of estrogen and increased risk of endometrial carcinoma development. The second control group included 27 randomly selected consecutive patients with endometrial carcinoma without identifiable associated conditions. Immunostaining for beta-catenin was performed on all cases; DNA was extracted and amplified by PCR with primers for beta-catenin, K-ras and PTEN genes. BAT-25 and BAT-26 were analyzed to assess for MSI. There were 16 endometrioid endometrial carcinomas, one mixed carcinoma and one clear cell carcinoma among patients in the tamoxifen group. All patients with ovarian hyperthecosis and adult granulosa cell tumor had endometrioid endometrial carcinoma. In the random control group, there were 26 endometrioid endometrial carcinomas and one carcinosarcoma. Immunohistochemical and mutational analysis for beta-catenin showed abnormalities in 4/11 (36%) and 3/10 (30%) informative cases in the tamoxifen group; 7/16 (44%) and 4/15 (27%) informative cases, respectively in the ovarian hyperthecosis group and 1/27 random control cases (4%) (P<0.05). Patients with tamoxifen exposure had more K-ras mutations and fewer PTEN mutations and MSI as opposed to controls, but the results were not statistically significant. In conclusion, there was a direct relationship between tamoxifen exposure and overexpression of beta-catenin oncoprotein, which is known to play a major role in the pathogenesis of estrogen-driven, type I endometrial adenocarcinoma.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2008;21;8;925-36

  • Duplication of paternal IGF2 or loss of maternal IGF2 imprinting occurs in half of Wilms tumors with various structural WT1 abnormalities.

    Haruta M, Arai Y, Sugawara W, Watanabe N, Honda S, Ohshima J, Soejima H, Nakadate H, Okita H, Hata J, Fukuzawa M and Kaneko Y

    Department of Cancer Diagnosis, Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Saitama, Japan.

    The WT1 gene essential for the embryonic kidney development is mutated in 15-25% of Wilms tumors (WTs). To clarify whether genetic subtypes of WT1 abnormalities are correlated with IGF2 or CTNNB1 alterations or clinicopathological characteristics, we performed comprehensive WT1, IGF2, and CTNNB1 analyses of 36 WTs with WT1 abnormalities using single nucleotide polymorphism arrays, and methylation analysis of the IGF2-H19 differentially methylated region. The tumors were classified into three subtypes based on WT1 abnormalities: 13 with WT1 deletion, 12 with WT1 mutation, and 11 with both deletion and mutation. IGF2 alterations were found in 50% (18/36), paternal uniparental disomy (UPD) of 11p13-11p15 in 13 tumors, UPD limited to 11p15 in 3, and loss of IGF2 imprinting in 2. Quantitative RT-PCR analysis showed that tumors with IGF2 alteration had higher levels of IGF2 mRNA than tumors without IGF2 alteration (P = 0.02). WT1 mRNA levels were very low in six of eight WTs with WT1 deletion, whereas four of eight WTs with WT1 mutation or both deletion and mutation showed higher levels of WT1 mRNA than fetal kidneys. WTs with WT1 mutations occurred in younger patients (P < 0.01), and WTs with mutations or both deletion and mutation (12/23) were more frequent in syndromic patients than WTs (1/13) with the deletion (P = 0.02). WTs with WT1 mutations or both deletion and mutation had the triphasic histological-type (15/23; P = 0.03) and CTNNB1 mutation (17/23; P = 0.03) more frequently than WTs with the deletion (2/13 and 4/13). Thus, three WT1 subtypes were correlated with certain genetic and clinicopathological characteristics.

    Genes, chromosomes & cancer 2008;47;8;712-27

  • Feedback regulation between zipcode binding protein 1 and beta-catenin mRNAs in breast cancer cells.

    Gu W, Wells AL, Pan F and Singer RH

    Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA. wgu@aecom.yu.edu

    ZBP1 (zipcode binding protein 1) is an RNA-binding protein involved in many posttranscriptional processes, such as RNA localization, RNA stability, and translational control. ZBP1 is abundantly expressed in embryonic development, but its expression is silenced in most adult tissues. Reactivation of the ZBP1 gene has been reported in various human tumors. In this study, we identified a detailed molecular mechanism of ZBP1 transactivation in breast cancer cells. We show that beta-catenin, a protein that functions in both cell adhesion and transcription, specifically binds to the ZBP1 promoter via a conserved beta-catenin/TCF4 response element and activates its gene expression. ZBP1 activation is also closely correlated with nuclear translocation of beta-catenin in human breast tumors. We further demonstrate feedback regulation by finding that ZBP1 physically associates with beta-catenin mRNA in vivo and increases its stability. These experiments suggest that in breast cancer cells, the expression of ZBP1 and the expression of beta-catenin are coordinately regulated. beta-Catenin mediates the transcription of the ZBP1 gene, while ZBP1 promotes the stability of beta-catenin mRNA.

    Funded by: NCI NIH HHS: CA83208; NIAMS NIH HHS: AR41480

    Molecular and cellular biology 2008;28;16;4963-74

  • Matrix metalloproteinases 2 and 9, E-cadherin, and beta-catenin expression in endometriosis, low-grade endometrial carcinoma and non-neoplastic eutopic endometrium.

    Shaco-Levy R, Sharabi S, Benharroch D, Piura B and Sion-Vardy N

    Department of Pathology, Soroka University Medical Center and Faculty of Health Sciences, Beer-Sheva, Israel. rsl@bgu.ac.il

    Objectives: Endometriosis and endometrial endometrioid carcinoma are both capable of invasion and metastasis, but their biological behavior is strikingly different. Matrix metalloproteinases (MMPs) and changes in adhesion molecules have a role in the pathogenesis of various physiological and pathological processes, as well as in the development of endometriosis and endometrioid endometrial carcinoma. We hypothesized that endometriosis, being a benign process, will show different MMPs and adhesion molecules expressions, compared to endometrioid endometrial carcinoma, a disease with potential of malignant behavior.

    We performed an immunohistochemical study to investigate expression of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), E-cadherin and beta-catenin in endometriosis, low-grade endometrial endometrioid carcinoma, and eutopic proliferative endometrium. Endometriotic tissues (n=15), low-grade endometrial endometrioid carcinomas (n=15), and unremarkable proliferative endometrium from women without endometriosis or carcinoma (n=10) were examined.

    Results: Endometriotic tissues showed statistically significantly stronger staining for MMP-9 and reduced beta-catenin expression when compared with proliferative endometrium. Endometrial endometrioid carcinoma showed decreased E-cadherin expression in comparison with proliferative endometrium. MMP-2 and MMP-9, and E-cadherin expressions were significantly higher and beta-catenin expression was significantly lower in endometriosis as compared to endometrioid carcinoma.

    Conclusions: We suggest that increased MMPs and altered beta-catenin may play a role in the pathogenesis of endometriosis. Decreased E-cadherin may be important in the development of endometrial endometrioid carcinoma. The changes in MMPs, E-cadherin and beta-catenin differ in endometriosis from those in endometrioid carcinoma, an interesting finding in view of the fact that both these diseases are capable of invasion and metastasis, but have different biological behavior.

    European journal of obstetrics, gynecology, and reproductive biology 2008;139;2;226-32

  • Hypoxia-inducible factor-1alpha obstructs a Wnt signaling pathway by inhibiting the hARD1-mediated activation of beta-catenin.

    Lim JH, Chun YS and Park JW

    Department of Pharmacology, Seoul National University College of Medicine, Chongno-gu, Seoul, Korea.

    Although a splice variant of mouse mARD1s was found to acetylate and destabilize hypoxia-inducible factor-1alpha (HIF-1alpha), human hARD1 has no such activities. Nonetheless, hARD1 has been reported to bind directly with HIF-1alpha. Here, we addressed the functional significance of the hARD1-HIF-1alpha interaction. Because hARD1 acetylates and activates beta-catenin, we examined whether HIF-1alpha regulates the hARD1-mediated activation of Wnt signaling. It was found that HIF-1alpha binds hARD1 through the oxygen-dependent degradation domain and, in so doing, dissociates hARD1 from beta-catenin, which prevents beta-catenin acetylation. In LiCl-stimulated HEK293 or cancer cell lines with active Wnt signaling, beta-catenin acetylation and activity were suppressed in hypoxia, and these suppressions were mediated by HIF-1alpha. Moreover, HIF-1alpha disruption of hARD1/beta-catenin repressed TCF4 activity, resulting in c-Myc suppression and p21(cip1) induction. In addition, we confirmed that the HIF-1alpha NH(2) terminal inactivates TCF4 by directly binding beta-catenin. In conclusion, HIF-1alpha was found to inactivate the Wnt signaling by binding to hARD1 or beta-catenin, which may contribute to the hypoxia-induced growth arrest of tumor cells.

    Cancer research 2008;68;13;5177-84

  • Inhibition of fibroblast growth factor 19 reduces tumor growth by modulating beta-catenin signaling.

    Pai R, Dunlap D, Qing J, Mohtashemi I, Hotzel K and French DM

    Department of Pathology, Genentech Incorporated, South San Francisco, California 94080, USA. rpai@gene.com

    Fibroblast growth factors (FGF) play important roles in development, angiogenesis, and cancer. FGF19 uniquely binds to FGF receptor 4 (FGFR4). Our previous study has shown that FGF19 transgenic tumors have an activated Wnt-pathway phenotype. Wnt signaling is implicated in initiating or promoting FGF signaling in various cell types and organs. In this study, we examined whether FGF19 or inhibition of FGF19 affects the beta-catenin signaling pathway using human colon cancer cell lines (HCT116, Colo201). Our results show that FGF19 increases tyrosine phosphorylation of beta-catenin and causes loss of beta-catenin-E-cadherin binding. FGF19 increases p-GSK3beta and active beta-catenin levels and anti-FGF19 antibody (1A6) treatment abrogates this effect of FGF19. Anti-FGF19 antibody treatment increases S33/S37/T41 phosphorylation and ubiquitination of beta-catenin. Ion-trap mass spectrometric analysis confirmed that 1A6 increases phosphorylation of beta-catenin in the NH(2) terminus. Using HCT116-paired beta-catenin knockout cells, we show that FGF19 induces TCF/LEF reporter activity in parental (WT/Delta45) and in WT/--but not in mutant (-/Delta45) cells, and that inhibition of endogenous FGF19 reduces this reporter activity, indicating that wild-type beta-catenin is accessible for modulation. FGFR4 knockdown using inducible short hairpin RNA significantly reduces the colony-forming ability in vitro and tumor growth in vivo. Although cleaved caspase-3 immunoreactivity remains unchanged, the number of ki67-positive nuclei is reduced in FGFR4 knockdown tumor xenograft tissues. Consistent with the reduced beta-catenin activation, Taqman analyses show that FGF19/FGFR4 inhibition reduced beta-catenin target gene (cyclin D1, CD44, c-jun, Cox-2, UPAR) expression. These findings highlight that FGF19/FGFR4 cross-talk with beta-catenin and that pathway intervention reduces tumor growth.

    Cancer research 2008;68;13;5086-95

  • The beta-catenin pathway is activated in focal nodular hyperplasia but not in cirrhotic FNH-like nodules.

    Rebouissou S, Couchy G, Libbrecht L, Balabaud C, Imbeaud S, Auffray C, Roskams T, Bioulac-Sage P and Zucman-Rossi J

    Inserm, U674, Génomique fonctionnelle des tumeurs solides, 27 rue Juliette Dodu, Paris F-75010, France.

    Focal nodular hyperplasias (FNHs) are benign liver lesions considered to be a hyperplastic response to increased blood flow in normal liver. In contrast, FNH-like lesions/nodules occur in cirrhotic liver but share similar histopathological features. We conducted a transcriptome analysis to identify biological pathways deregulated in FNH.

    Methods: Gene expression profiles obtained in FNH and normal livers were compared. Differentially-expressed genes were validated using quantitative-RT-PCR in 70 benign liver tumors including FNH-like lesions.

    Results: Among the deregulated genes in FNHs, 19 displayed physiological restricted distribution in the normal liver. All six perivenous genes were up-regulated in FNH, whereas 13 periportal genes were down-regulated. Almost all these genes are known to be regulated by beta-catenin. Glutamine synthetase was markedly overexpressed in anastomosed areas usually centered on visible veins. Moreover, activated hypophosphorylated beta-catenin protein accumulated in FNH in the absence of activating mutations. These results suggest the zonated activation of the beta-catenin pathway in FNH, whereas the other benign hepatocellular tumors, including FNH-like lesions, demonstrated an entirely different pattern of beta-catenin expression.

    Conclusions: In FNH, increased activation of the beta-catenin pathway was found restricted to enlarged perivenous areas. FNH-like nodules may have a different pathogenetic origin.

    Journal of hepatology 2008;49;1;61-71

  • Beta-catenin mutations do not contribute to cardiac fibroma pathogenesis.

    Miller DV, Wang H, Wang H, Fealey ME and Tazelaar HD

    Division of Anatomic Pathology, 200 First Street SW, Mayo Clinic, Rochester, MN 55905, USA. miller.dylan@mayo.edu

    Cardiac fibromas are the 2nd most common benign cardiac tumor occurring in children and bear a striking morphologic resemblance to soft tissue or desmoid fibromatosis. Since activating mutations in beta-catenin are common in desmoid fibromatosis as well as other spindle cell proliferations, the aim of our study was to determine if such mutations could be identified in cardiac fibroma. Nine cardiac fibromas from patients with surgical resection were examined for beta-catenin mutations by immunoperoxidase staining for beta-catenin protein and DNA sequencing of a region in exon 3 of the beta-catenin gene, where relatively conserved mutations have been described in desmoid fibromatosis. The mean age of the patients was 7.6 years (range: 10 weeks to 27 years), and 6 of the patients were male. No nuclear staining for beta-catenin was seen in the fibroma cells by immunoperoxidase methods. The beta-catenin exon 3 sequence data showed no mutations in any of the 9 tumors. We conclude that despite their morphologic similarity, cardiac fibroma and desmoid fibromatosis do not share this common molecular pathway of neoplastic growth.

    Pediatric and developmental pathology : the official journal of the Society for Pediatric Pathology and the Paediatric Pathology Society 2008;11;4;291-4

  • Concomitant activation of Wnt pathway and loss of mismatch repair function in human melanoma.

    Castiglia D, Bernardini S, Alvino E, Pagani E, De Luca N, Falcinelli S, Pacchiarotti A, Bonmassar E, Zambruno G and D'Atri S

    Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata-IRCCS, Rome, Italy. d.castiglia@idi.it

    Constitutive activation of the Wnt pathway plays a key role in the development of colorectal cancer and has also been implicated in the pathogenesis of other malignancies. Deregulation of Wnt signaling mainly occurs through genetic alterations of APC, the beta-catenin gene (CTNNB1), AXIN1 and AXIN2, leading to stabilization of beta-catenin. Physiologically, AXIN2 is transcriptionally induced on Wnt signaling activation and acts as a negative feedback regulator of the pathway. In colorectal cancer, mutations in CTNNB1 and AXIN2 occur preferentially in tumors with inactivation of the mismatch repair (MMR) genes MSH2, MLH1, or PMS2. In this study, the expression of beta-catenin and AXIN2, and the mutational status of CTNNB1, APC, and AXIN2 were evaluated in two MMR-deficient (PR-Mel and MR-Mel) and seven MMR-proficient human melanoma cell lines. Only PR-Mel and MR-Mel cells showed nuclear accumulation of beta-catenin and expression of the AXIN2 gene, and hence, constitutive activation of Wnt signaling. Mutational analysis identified a somatic heterozygous missense mutation in CTNNB1 exon three and a germline heterozygous deletion within AXIN2 exon seven in PR-Mel cells, and a somatic biallelic deletion within APC in MR-Mel cells. Deregulation of Wnt signaling and a defective MMR system were also present in the original tumor of PR and MR patients. Thus, we describe additional melanomas with mutations in CTNNB1 and APC, identify for the first time a germline AXIN2 mutation in a melanoma patient and suggest that inactivation of the MMR system and deregulation of the Wnt/beta-catenin signaling pathway cooperate to promote melanoma development and/or progression.

    Genes, chromosomes & cancer 2008;47;7;614-24

  • Direct interaction of tumor suppressor CEACAM1 with beta catenin: identification of key residues in the long cytoplasmic domain.

    Jin L, Li Y, Chen CJ, Sherman MA, Le K and Shively JE

    Division of Immunology, Beckman Research Institute of the City of Hope, 1450 E. Duarte Rd., Duarte, CA 91010, USA.

    CEACAM1-4L (carcinoembryonic antigen cell adhesion molecule 1, with 4 extracellular Ig-like domains and a long, 71 amino acid cytoplasmic domain) is expressed in epithelial cells and activated T-cells, but is down-regulated in most epithelial cell cancers and T-cell leukemias. A highly conserved sequence within the cytoplasmic domain has ca 50% sequence homology with Tcf-3 and -4, transcription factors that bind beta-catenin, and to a lesser extent (32% homology), with E-cadherin that also binds beta-catenin. We show by quantitative yeast two-hybrid, BIAcore, GST-pull down, and confocal analyses that this domain directly interacts with beta-catenin, and that H-469 and K-470 are key residues that interact with the armadillo repeats of beta-catenin. Jurkat cells transfected with CEACAM1-4L have 2-fold less activity in the TOPFLASH reporter assay, and in MCF7 breast cancer cells that fail to express CEACAM1, transfection with CEACAM1 and growth in Ca2+ media causes redistribution of beta-catenin from the cytoplasm to the cell membrane, demonstrating a functional role for the long cytoplasmic domain of CEACAM1 in regulation of beta-catenin activity.

    Funded by: NCI NIH HHS: CA 84202, R01 CA084202-08

    Experimental biology and medicine (Maywood, N.J.) 2008;233;7;849-59

  • Wnt3a and Dkk1 regulate distinct internalization pathways of LRP6 to tune the activation of beta-catenin signaling.

    Yamamoto H, Sakane H, Yamamoto H, Michiue T and Kikuchi A

    Department of Biochemistry, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.

    Wnt and Dickkopf (Dkk) regulate the stabilization of beta-catenin antagonistically in the Wnt signaling pathway; however, the molecular mechanism is not clear. In this study, we found that Wnt3a acts in parallel to induce the caveolin-dependent internalization of low-density-lipoprotein receptor-related protein 6 (LRP6), as well as the phosphorylation of LRP6 and the recruitment of Axin to LRP6 on the cell surface membrane. The phosphorylation and internalization of LRP6 occurred independently of one another, and both were necessary for the accumulation of beta-catenin. In contrast, Dkk1, which inhibits Wnt3a-dependent stabilization of beta-catenin, induced the internalization of LRP6 with clathrin. Knockdown of clathrin suppressed the Dkk1-dependent inhibition of the Wnt3a response. Furthermore, Dkk1 reduced the distribution of LRP6 in the lipid raft fraction where caveolin is associated. These results indicate that Wnt3a and Dkk1 shunt LRP6 to distinct internalization pathways in order to activate and inhibit the beta-catenin signaling, respectively.

    Developmental cell 2008;15;1;37-48

  • Chibby cooperates with 14-3-3 to regulate beta-catenin subcellular distribution and signaling activity.

    Li FQ, Mofunanya A, Harris K and Takemaru K

    Department of Pharmacological Sciences and 2Graduate Program in Genetics, State University of New York at Stony Brook, Stony Brook, NY 11794, USA. li@pharm.stonybrook.edu

    beta-Catenin functions in both cell-cell adhesion and as a transcriptional coactivator in the canonical Wnt pathway. Nuclear accumulation of beta-catenin is the hallmark of active Wnt signaling and is frequently observed in human cancers. Although beta-catenin shuttles in and out of the nucleus, the molecular mechanisms underlying its translocation remain poorly understood. Chibby (Cby) is an evolutionarily conserved molecule that inhibits beta-catenin-mediated transcriptional activation. Here, we identified 14-3-3epsilon and 14-3-3zeta as Cby-binding partners using affinity purification/mass spectrometry. 14-3-3 proteins specifically recognize serine 20 within the 14-3-3-binding motif of Cby when phosphorylated by Akt kinase. Notably, 14-3-3 binding results in sequestration of Cby into the cytoplasm. Moreover, Cby and 14-3-3 form a stable tripartite complex with beta-catenin, causing beta-catenin to partition into the cytoplasm. Our results therefore suggest a novel paradigm through which Cby acts in concert with 14-3-3 proteins to facilitate nuclear export of beta-catenin, thereby antagonizing beta-catenin signaling.

    Funded by: NIDDK NIH HHS: R01 DK073191

    The Journal of cell biology 2008;181;7;1141-54

  • Nuclear beta-catenin expression as a prognostic factor in advanced colorectal carcinoma.

    Elzagheid A, Buhmeida A, Korkeila E, Collan Y, Syrjanen K and Pyrhonen S

    Department of Pathology, University of Turku, Kiinamyllynkatu 10, FIN-20520, Turku, Finland. adibel@utu.fi

    Aim: To investigate the changing pattern of beta-catenin expression and its prognostic value in advanced colorectal cancer (CRC).

    Methods: Archival tumor samples were analyzed for beta-catenin using immunohistochemistry (IHC) in 95 patients with advanced CRC.

    Results: Membranous beta-catenin expression was found in the normal colorectal epithelium. Almost 100% of CRC cases showed membranous and cytoplasmic expression, and 55 (58%) cases showed nuclear expression. In univariate (Kaplan-Meier) survival analysis, only the nuclear index (NI) was a significant predictor of disease free survival (DFS) (P = 0.023; n = 35), with a NI above the median associated with longer DFS (34.2 mo) than those with a NI below the median (15.5 mo) (P = 0.045, ANOVA). The other indices were not significant predictors of DFS, and none of the three tested indices (for membranous, cytoplasmic, or nuclear expression) predicted disease-specific survival (DSS). However, when dichotomized as positive or negative nuclear expression, the former was a significant predictor of more favorable DFS (P = 0.041) and DSS (P = 0.046).

    Conclusion: Nuclear beta-catenin expression provides additional information in predicting patient outcome in advanced CRC.

    World journal of gastroenterology 2008;14;24;3866-71

  • The molecular mechanism governing the oncogenic potential of SOX2 in breast cancer.

    Chen Y, Shi L, Zhang L, Li R, Liang J, Yu W, Sun L, Yang X, Wang Y, Zhang Y and Shang Y

    Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China.

    SOX genes encode a family of high-mobility group transcription factors that play critical roles in organogenesis. The functional specificity of different SOX proteins and the tissue specificity of a particular SOX factor are largely determined by the differential partnership of SOX transcription factors with other transcription regulators, many of which have not yet been discovered. Virtually all members of the SOX family have been found to be deregulated in a wide variety of tumors. However, little is known about the cellular and molecular behaviors involved in the oncogenic potential of SOX proteins. Using cell culture experiments, tissue analysis, molecular profiling, and animal studies, we report here that SOX2 promotes cell proliferation and tumorigenesis by facilitating the G(1)/S transition and through its transcription regulation of the CCND1 gene in breast cancer cells. In addition, we identified beta-catenin as the transcription partner for SOX2 and demonstrated that SOX2 and beta-catenin act in synergy in the transcription regulation of CCND1 in breast cancer cells. Our experiments not only determined a role for SOX2 in mammary tumorigenesis but also revealed another activity of the multifunctional protein, beta-catenin.

    The Journal of biological chemistry 2008;283;26;17969-78

  • Ser-249 TP53 and CTNNB1 mutations in circulating free DNA of Egyptian patients with hepatocellular carcinoma versus chronic liver diseases.

    Hosny G, Farahat N, Tayel H and Hainaut P

    Department of Environmental Studies, Environmental Health and Molecular Carcinogenesis Division, Institute of Graduate Studies and Research, University of Alexandria, PO Box 832, El-Shatby, Alexandria, Egypt. gihan_hosny@yahoo.com

    Circulating free DNA (CFDNA) has been shown to be a good source of liver tissue-derived DNA in African and Asian patients with chronic liver disease or HCC. In Egypt, HCC is a frequent carcinoma and mostly occur in the context of chronic infection by HCV, a widespread infection in the Egyptian population. Here we have examined the presence of mutations in TP53 at codon 249 (Ser-249, considered as a hallmark of mutagenesis by aflatoxin) and in CTNNB1 (gene encoding beta-catenin) in CFDNA of patients with HCC or chronic liver disease, from Alexandria, Egypt. The DNA concentrations were significantly higher in HCC patients compared to HBV and HCV carriers without cancer, and to sero-negative individuals. Ser-249 TP53 mutations were determined using PCR-restriction digestion (RFLP) in CFDNA of 255 subjects, and confirmed by sequencing. Ser-249 was found in CFDNA of 12 subjects (4.8%), with the highest prevalence in subjects with chronic liver disease and infection by HBV (6/36; 16.7%) Mutations in CTNNB1 were examined using PCR combined to DHPLC and followed by sequencing. No mutations were found in CTNNB1 neither in CFDNA or in tumour tissue. In parallel, studies on DNA extracted from 20 HCC biopsies showed the presence of ser-249 mutation in two cases (10%). These results indicate that mutagenesis by aflatoxin may play a role in hepatocarcinogenesis in Egypt, and CFDNA may serve as a convenient source of material in monitoring the effects of aflatoxin exposure and viral infections in chronic liver disease and cancer.

    Cancer letters 2008;264;2;201-8

  • Stabilizing mutation of CTNNB1/beta-catenin and protein accumulation analyzed in a large series of parathyroid tumors of Swedish patients.

    Björklund P, Lindberg D, Akerström G and Westin G

    Department of Surgical Sciences, Endocrine Unit, Uppsala University, Uppsala University Hospital, SE-751 85 Uppsala, Sweden. peyman.bjorklund@surgsci.uu.se

    Background: Aberrant accumulation of beta-catenin plays an important role in a variety of human neoplasms. We recently reported accumulation of beta-catenin in parathyroid adenomas from patients with primary hyperparathyroidism (pHPT). In CTNNB1 exon 3, we detected a stabilizing mutation (S37A) in 3 out of 20 analyzed adenomas. The aim of the present study was to determine the frequency and zygosity of mutations in CTNNB1 exon 3, and beta-catenin accumulation in a large series of parathyroid adenomas of Swedish patients.

    Results: The mutation S37A (TCT > GCT) was detected by direct DNA sequencing of PCR fragments in 6 out of 104 sporadic parathyroid adenomas (5.8%). Taking our previous study into account, a total of 9 out of 124 (7.3%) adenomas displayed the same mutation. The mutations were homozygous by DNA sequencing, restriction enzyme cleavage, and gene copy number determination using the GeneChip 500 K Mapping Array Set. All tumors analyzed by immunohistochemistry, including those with mutation, displayed aberrant beta-catenin accumulation. Western blotting revealed a slightly higher expression level of beta-catenin and nonphosphorylated active beta-catenin in tumors with mutation compared to those without. Presence of the mutation was not related to distinct clinical characteristics.

    Conclusion: Aberrant accumulation of beta-catenin is very common in parathyroid tumors, and is caused by stabilizing homozygous mutation in 7.3% of Swedish pHPT patients.

    Molecular cancer 2008;7;53

  • Nuclear GSK-3beta inhibits the canonical Wnt signalling pathway in a beta-catenin phosphorylation-independent manner.

    Caspi M, Zilberberg A, Eldar-Finkelman H and Rosin-Arbesfeld R

    Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.

    Beta-catenin is the central signalling molecule of the canonical Wnt pathway, where it activates target genes in a complex with lymphoid enhancer factor/T-cell factor transcription factors in the nucleus. The regulation of beta-catenin activity is thought to occur via a cytoplasmatic multiprotein complex that includes the serine/threonine kinase glycogen synthase kinase-3beta (GSK-3beta) that phosphorylates beta-catenin, marking it for degradation by the proteasome. Here, we provide evidence showing that GSK-3beta has a nuclear function in downregulating the activity of beta-catenin. Using colorectal cell lines that express a mutant form of beta-catenin, which cannot be phosphorylated by GSK-3beta and ectopically expressed mutant beta-catenin protein, we show that nuclear GSK-3beta functions in a mechanism that does not involve beta-catenin phosphorylation to reduce the levels of Wnt signalling. We show that GSK-3beta enters the nucleus, forms a complex with beta-catenin and lowers the levels of beta-catenin/TCF-dependent transcription in a mechanism that involves GSK-3beta-Axin binding.

    Oncogene 2008;27;25;3546-55

  • Reciprocal negative regulation between S100A7/psoriasin and beta-catenin signaling plays an important role in tumor progression of squamous cell carcinoma of oral cavity.

    Zhou G, Xie TX, Zhao M, Jasser SA, Younes MN, Sano D, Lin J, Kupferman ME, Santillan AA, Patel V, Gutkind JS, Ei-Naggar AK, Emberley ED, Watson PH, Matsuzawa SI, Reed JC and Myers JN

    Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030-4009, USA.

    Overexpression of S100A7 (psoriasin), a small calcium-binding protein, has been associated with the development of psoriasis and carcinomas in different types of epithelia, but its precise functions are still unknown. Using human tissue specimens, cultured cell lines, and a mouse model, we found that S100A7 is highly expressed in preinvasive, well-differentiated and early staged human squamous cell carcinoma of the oral cavity (SCCOC), but little or no expression was found in poorly differentiated, later-staged invasive tumors. Interestingly, our results showed that S100A7 inhibits both SCCOC cell proliferation in vitro and tumor growth/invasion in vivo. Furthermore, we demonstrated that S100A7 is associated with the beta-catenin complex, and inhibits beta-catenin signaling by targeting beta-catenin degradation via a noncanonical mechanism that is independent of GSK3beta-mediated phosphorylation. More importantly, our results also indicated that beta-catenin signaling negatively regulates S100A7 expression. Thus, this reciprocal negative regulation between S100A7 and beta-catenin signaling implies their important roles in tumor development and progression. Despite its high levels of expression in early stage SCCOC tumorigenesis, S100A7 actually inhibits SCCOC tumor growth/invasion as well as tumor progression. Downregulation of S100A7 in later stages of tumorigenesis increases beta-catenin signaling, leading to promotion of tumor growth and tumor progression.

    Funded by: NCI NIH HHS: CA16672, CA69381, P30 CA016672; NIDCR NIH HHS: R01DE01461301

    Oncogene 2008;27;25;3527-38

  • Plasma membrane recruitment of dephosphorylated beta-catenin upon activation of the Wnt pathway.

    Hendriksen J, Jansen M, Brown CM, van der Velde H, van Ham M, Galjart N, Offerhaus GJ, Fagotto F and Fornerod M

    Department of Tumor Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.

    The standard model of Wnt signaling specifies that after receipt of a Wnt ligand at the membranous receptor complex, downstream mediators inhibit a cytoplasmic destruction complex, allowing beta-catenin to accumulate in the cytosol and nucleus and co-activate Wnt target genes. Unexpectedly, shortly after Wnt treatment, we detected the dephosphorylated form of beta-catenin at the plasma membrane, where it displayed a discontinuous punctate labeling. This pool of beta-catenin could only be detected in E-cadherin(-/-) cells, because in E-cadherin(+/+) cells Wnt-induced, membranous beta-catenin was concealed by a constitutive junctional pool. Wnt-signaling-dependent dephosphorylated beta-catenin colocalized at the plasma membrane with two members of the destruction complex -- APC and axin -- and the activated Wnt co-receptor LRP6. beta-catenin induced through the Wnt receptor complex was significantly more competent transcriptionally than overexpressed beta-catenin, both in cultured cells and in early Xenopus embryos. Our data reveal a new step in the processing of the Wnt signal and suggest regulation of signaling output beyond the level of protein accumulation.

    Journal of cell science 2008;121;11;1793-802

  • alpha-Catenin overrides Src-dependent activation of beta-catenin oncogenic signaling.

    Inge LJ, Rajasekaran SA, Wolle D, Barwe SP, Ryazantsev S, Ewing CM, Isaacs WB and Rajasekaran AK

    Nemours Center for Childhood Cancer Research, Alfred I. DuPont Hospital for Children, 1701 Rockland Road, Wilmington, DE 19803, USA.

    Loss of alpha-catenin is one of the characteristics of prostate cancer. The catenins (alpha and beta) associated with E-cadherin play a critical role in the regulation of cell-cell adhesion. Tyrosine phosphorylation of beta-catenin dissociates it from E-cadherin and facilitates its entry into the nucleus, where beta-catenin acts as a transcriptional activator inducing genes involved in cell proliferation. Thus, beta-catenin regulates cell-cell adhesion and cell proliferation. Mechanisms controlling the balance between these functions of beta-catenin invariably are altered in cancer. Although a wealth of information is available about beta-catenin deregulation during oncogenesis, much less is known about how or whether alpha-catenin regulates beta-catenin functions. In this study, we show that alpha-catenin acts as a switch regulating the cell-cell adhesion and proliferation functions of beta-catenin. In alpha-catenin-null prostate cancer cells, reexpression of alpha-catenin increased cell-cell adhesion and decreased beta-catenin transcriptional activity, cyclin D1 levels, and cell proliferation. Further, Src-mediated tyrosine phosphorylation of beta-catenin is a major mechanism for decreased beta-catenin interaction with E-cadherin in alpha-catenin-null cells. alpha-Catenin attenuated the effect of Src phosphorylation by increasing beta-catenin association with E-cadherin. We also show that alpha-catenin increases the sensitivity of prostate cancer cells to a Src inhibitor in suppressing cell proliferation. This study reveals for the first time that alpha-catenin is a key regulator of beta-catenin transcriptional activity and that the status of alpha-catenin expression in tumor tissues might have prognostic value for Src targeted therapy.

    Funded by: NIDDK NIH HHS: DK 56216, R01 DK056216, R01 DK056216-06, R01 DK056216-07, R01 DK056216-08; NIGMS NIH HHS: F31 GM068985, F31-GM068985

    Molecular cancer therapeutics 2008;7;6;1386-97

  • Beta-catenin signalling in mesenchymal islet-derived precursor cells.

    Ikonomou L, Geras-Raaka E, Raaka BM and Gershengorn MC

    Clinical Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-8029, USA.

    Objectives: Previously, we characterized human islet-derived precursor cells (hIPCs) as mesenchymal stem cells that migrate out from islets in vitro and can differentiate into functional islet-like structures following proliferative expansion. Here, we investigate the role of beta-catenin signalling in derivation and proliferation of hIPCs.

    Localization of beta-catenin was performed using confocal microscopy. Expression levels of beta-catenin target genes were measured by quantitative real-time polymerase chain reaction. Loss-of-function studies were performed using specific short interfering RNAs.

    Results: Immunostaining of islet outgrowths revealed translocation of beta-catenin from plasma membranes in intact islets to the nucleus in cells migrating out. There were no nuclear beta-catenin-positive cells in intact islets whereas between 35% and 70% of cells in established hIPC cultures exhibited nuclear beta-catenin. Transcripts for beta-catenin target genes were increased in hIPCs compared to those in islets. Beta-catenin translocated to the cell membrane when hIPCs formed epithelial cell clusters. In proliferating hIPCs, there was a strong correlation between markers of proliferation and nuclear beta-catenin. Treatment of hIPCs with the glycogen synthase kinase-3beta inhibitor (2'Z,3'E)-6-Bromoindirubin-3'-oxime increased intracellular beta-catenin but reduced nuclear beta-catenin, and was associated with reduced cell proliferation. Finally, knockdown of beta-catenin decreased beta-catenin target gene expression and hIPC proliferation.

    Conclusions: These results support a functional role for beta-catenin during proliferation of hIPCs and suggest that activated beta-catenin signalling may also be important during hIPC derivation from islets.

    Cell proliferation 2008;41;3;474-91

  • CHD8 is an ATP-dependent chromatin remodeling factor that regulates beta-catenin target genes.

    Thompson BA, Tremblay V, Lin G and Bochar DA

    Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA.

    ATP-dependent chromatin remodeling by the CHD family of proteins plays an important role in the regulation of gene transcription. Here we report that full-length CHD8 interacts directly with beta-catenin and that CHD8 is also recruited specifically to the promoter regions of several beta-catenin-responsive genes. Our results indicate that CHD8 negatively regulates beta-catenin-targeted gene expression, since short hairpin RNA against CHD8 results in the activation of several beta-catenin target genes. This regulation is also conserved through evolution; RNA interference against kismet, the apparent Drosophila ortholog of CHD8, results in a similar activation of beta-catenin target genes. We also report the first demonstration of chromatin remodeling activity for a member of the CHD6-9 family of proteins, suggesting that CHD8 functions in transcription through the ATP-dependent modulation of chromatin structure.

    Funded by: NCI NIH HHS: 5 P30 CA46592, P30 CA046592; NIGMS NIH HHS: T32 GM007315

    Molecular and cellular biology 2008;28;12;3894-904

  • DACT3 is an epigenetic regulator of Wnt/beta-catenin signaling in colorectal cancer and is a therapeutic target of histone modifications.

    Jiang X, Tan J, Li J, Kivimäe S, Yang X, Zhuang L, Lee PL, Chan MT, Stanton LW, Liu ET, Cheyette BN and Yu Q

    Cancer Biology and Pharmacology, Genome Institute of Singapore, A*STAR (Agency for Science, Technology and Research), Biopolis, 138672 Singapore.

    Genetic and epigenetic defects in Wnt/beta-catenin signaling play important roles in colorectal cancer progression. Here we identify DACT3, a member of the DACT (Dpr/Frodo) gene family, as a negative regulator of Wnt/beta-catenin signaling that is transcriptionally repressed in colorectal cancer. Unlike other Wnt signaling inhibitors that are silenced by DNA methylation, DACT3 repression is associated with bivalent histone modifications. Remarkably, DACT3 expression can be robustly derepressed by a pharmacological combination that simultaneously targets both histone methylation and deacetylation, leading to strong inhibition of Dishevelled (Dvl)-mediated Wnt/beta-catenin signaling and massive apoptosis of colorectal cancer cells. Our study identifies DACT3 as an important regulator of Wnt/beta-catenin signaling in colorectal cancer and suggests a potential strategy for therapeutic control of Wnt/beta-catenin signaling in colorectal cancer.

    Funded by: NICHD NIH HHS: 1R01 HD055300, R01 HD055300, R01 HD055300-01; NIMH NIH HHS: K08 MH001750, K08 MH001750-05, K08 MH01750

    Cancer cell 2008;13;6;529-41

  • Diagnostic use of nuclear beta-catenin expression for the assessment of endometrial stromal tumors.

    Jung CK, Jung JH, Lee A, Lee YS, Choi YJ, Yoon SK and Lee KY

    Department of Hospital Pathology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

    Alterations in beta-catenin degradation cause it to accumulate to immunohistochemically detectable levels in the nuclei of tumor cells. Although it has been shown that nuclear beta-catenin immunostaining is useful for the diagnosis of some mesenchymal tumors, there is little known about beta-catenin expression in endometrial stromal tumors. In this study, nuclear beta-catenin immunoreactivity was evaluated in normal endometrium and endometrial mesenchymal tumors and then compared with that of CD10. The endometrial mesenchymal tumors evaluated included endometrial stromal nodules (n=2), low-grade endometrial stromal sarcomas (n=12), undifferentiated endometrial sarcomas (n=8) and uterine cellular leiomyomata (n=9). In addition, direct DNA sequencing of beta-catenin exon 3 was conducted in 15 endometrial stromal tumors. Normal endometrial stromal cells showed strong cytoplasmic reactivity for CD10 but no detectable reactivity for beta-catenin. Nuclear beta-catenin immunoreactivity was detected in 11 low-grade endometrial stromal sarcomas (92%) and 6 undifferentiated endometrial sarcomas (75%). Ten low-grade endometrial stromal sarcomas (83%) and six undifferentiated endometrial sarcomas (75%) were positive for CD10. Eight low-grade endometrial stromal sarcomas (67%) exhibited diffuse, strong nuclear immunoreactivity with beta-catenin, whereas only four cases (33%) expressed diffuse, strong immunoreactivity with CD10. All nine cases of uterine cellular leiomyomata were completely negative for both CD10 and beta-catenin. beta-catenin mutations were rare in endometrial stromal tumors. Taken together, these results indicate that nuclear beta-catenin immunostaining can serve as a sensitive immunohistochemical marker for the diagnosis of endometrial stromal tumors and is useful for differentiating low-grade endometrial stromal sarcomas from uterine cellular leiomyomata.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2008;21;6;756-63

  • Regulation of Wnt signaling by the nuclear pore complex.

    Shitashige M, Satow R, Honda K, Ono M, Hirohashi S and Yamada T

    Chemotherapy Division and Cancer Proteomics Project, National Cancer Center Research Institute, Tokyo, Japan.

    The function of beta-catenin as a transcriptional coactivator of T-cell factor-4 (TCF-4) is crucial for colorectal carcinogenesis. However, beta-catenin has no nuclear localization signal, and the mechanisms by which beta-catenin is imported into the nucleus and forms a complex with the TCF-4 nuclear protein are poorly understood.

    Methods: Proteins of 2 colorectal cancer cell lines, HCT-116 and DLD1, were immunoprecipitated with anti-TCF-4 antibody and analyzed directly by nanoflow liquid chromatography and mass spectrometry. The functional significance of nuclear pore complex (NPC) proteins in Wnt signaling was evaluated by in vitro and in vivo sumoylation, luciferase reporter, and colony formation assays.

    Results: TCF-4 interacted with a large variety of NPC proteins including ras-related nuclear protein (Ran), Ran binding protein-2 (RanBP2), and Ran GTPase-activating protein-1 (RanGAP1). The NPC protein RanBP2 functioned as the small ubiquitin-related modifier (SUMO) E3 ligase of TCF-4, and sumoylation of TCF-4 enhanced the interaction between TCF-4 and beta-catenin. The overexpression of NPC proteins increased the nuclear import of the TCF-4 and beta-catenin proteins and enhanced the transcriptional activity. NPC proteins increased the growth of colorectal cancer cells, whereas sentrin-specific protease-2 inhibited it.

    Conclusions: Through a comprehensive proteomics approach, we revealed that NPC functions as a novel regulator of Wnt signaling and is possibly involved in colorectal carcinogenesis. A new drug targeting the interactions of TCF-4 with NPC proteins as well as their sumoylation activity might be effective for suppressing aberrant Wnt signaling and the proliferation of colorectal cancer cells.

    Gastroenterology 2008;134;7;1961-71, 1971.e1-4

  • Upregulation of beta-catenin levels in superior frontal cortex of chronic alcoholics.

    Al-Housseini AM, Sivanandam TM, Bradbury EL, Tannenberg RK, Dodd PR and Gu Q

    Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.

    Background: Chronic and excessive alcohol misuse results in neuroadaptive changes in the brain. The complex nature of behavioral, psychological, emotional, and neuropathological characteristics associated with alcoholism is likely a reflection of the network of proteins that are affected by alcohol-induced gene expression patterns in specific brain regions. At the molecular level, however, knowledge remains limited regarding alterations in protein expression levels affected by chronic alcohol abuse. Thus, novel techniques that allow a comprehensive assessment of this complexity will enable the simultaneous assessment of changes across a group of proteins in the relevant neural circuitry.

    Methods: A proteomics analysis was performed using antibody microarrays to determine differential protein levels in superior frontal cortices between chronic alcoholics and age- and gender-matched control subjects. Seventeen proteins related to the catenin signaling pathway were analyzed, including alpha-, beta-, and delta-catenins, their upstream activators cadherin-3 (type I cadherin) and cadherin-5 (type II cadherin), and 5 cytoplasmic regulators c-Src, CK1 epsilon, GSK-3beta, PP2A-C alpha, and APC, as well as the nuclear complex partner of beta-catenin CBP and 2 downstream genes Myc and cyclin D1. ILK, G(alpha1), G(beta1), and G(beta2), which are activity regulators of GSK-3beta, were also analyzed.

    Results: Both alpha- and beta-catenin showed significantly increased levels, while delta-catenin did not change significantly, in chronic alcoholics. In addition, the level of the beta-catenin downstream gene product Myc was significantly increased. Average levels of the catenin regulators c-Src, CK1 epsilon, and APC were also increased in chronic alcoholics, but the changes were not statistically significant.

    Conclusion: Chronic and excessive alcohol consumption leads to an upregulation of alpha- and beta-catenin levels, which in turn increase downstream gene expressions such as Myc that is controlled by beta-catenin signaling. This study showed that the beta-catenin signal transduction pathway was upregulated by chronic alcohol abuse, and prompts further investigation of mechanisms underlying the upregulation of alpha- and beta-catenins in alcoholism, which may have considerable pathogenic and therapeutic relevance.

    Funded by: NIAAA NIH HHS: AA12404

    Alcoholism, clinical and experimental research 2008;32;6;1080-90

  • Wilms tumor genetics: mutations in WT1, WTX, and CTNNB1 account for only about one-third of tumors.

    Ruteshouser EC, Robinson SM and Huff V

    Department of Cancer Genetics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA. crutesho@mdanderosn.org

    Wilms tumor is genetically heterogeneous, and until recently only one Wilms tumor gene was known, WT1 at 11p13. However, WT1 is altered in only approximately 20% of Wilms tumors. Recently a novel gene, WTX at Xq11.1, was reported to be mutated in Wilms tumors. No overlap between tumors with mutations in WTX and WT1 was noted, suggesting that WT1 and WTX mutations could account for the genetic basis of roughly half of Wilms tumors. To assess the frequency of WTX mutations and their relationship to WT1 mutations in a larger (n = 125) panel of Wilms tumors which had been thoroughly assessed for mutations in WT1, we conducted a complete mutational analysis of WTX that included sequencing of the entire coding region and quantitative PCR to identify deletions of the WTX gene. Twenty-three (18.4%) tumors carried a total of 24 WTX mutations, a lower WTX mutation frequency than that previously observed. Surprisingly, we observed an equivalent frequency of WTX mutations in tumors with mutations in either or both WT1 and CTNNB1 (20.0%) and tumors with no mutation in either WT1 or CTNNB1 (17.5%). WTX has been reported to play a role in the WNT/beta-catenin signaling pathway, and, interestingly, WTX deletion/truncation mutations appeared to be rare in tumors carrying exon 3 mutations of CTNNB1, encoding beta-catenin. Our findings indicate that WT1 and WTX mutations occur with similar frequency, that they partially overlap in Wilms tumors, and that mutations in WT1, WTX, and CTNNB1 underlie the genetic basis of about one-third of Wilms tumors.

    Funded by: NCI NIH HHS: CA16672, CA34936; NIDDK NIH HHS: DK69599

    Genes, chromosomes & cancer 2008;47;6;461-70

  • HDAC6 is required for epidermal growth factor-induced beta-catenin nuclear localization.

    Li Y, Zhang X, Polakiewicz RD, Yao TP and Comb MJ

    Cell Signaling Technology, Danvers, Massachusetts 01923, USA.

    Nuclear translocation of beta-catenin is a hallmark of Wnt signaling and is associated with various cancers. In addition to the canonical Wnt pathway activated by Wnt ligands, growth factors such as epidermal growth factor (EGF) also induce beta-catenin dissociation from the adherens junction complex, translocation into the nucleus, and activation of target genes such as c-myc. Here we report that EGF-induced beta-catenin nuclear localization and activation of c-myc are dependent on the deacetylase HDAC6. We show that EGF induces HDAC6 translocation to the caveolae membrane and association with beta-catenin. HDAC6 deacetylates beta-catenin at lysine 49, a site frequently mutated in anaplastic thyroid cancer, and inhibits beta-catenin phosphorylation at serine 45. HDAC6 inactivation blocks EGF-induced beta-catenin nuclear localization and decreases c-Myc expression, leading to inhibition of tumor cell proliferation. These results suggest that EGF-induced nuclear localization of beta-catenin is regulated by HDAC6-dependent deacetylation and provide a new mechanism by which HDAC inhibitors prevent tumor growth.

    Funded by: NINDS NIH HHS: R01 NS054022, R01 NS054022-03

    The Journal of biological chemistry 2008;283;19;12686-90

  • Beta-catenin mediates alteration in cell proliferation, motility and invasion of prostate cancer cells by differential expression of E-cadherin and protein kinase D1.

    Syed V, Mak P, Du C and Balaji KC

    Division of Urology, Department of Surgery, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.

    We have previously demonstrated that Protein Kinase D1 (PKD1) interacts with E-cadherin and is associated with altered cell aggregation and motility in prostate cancer (PC). Because both PKD1 and E-cadherin are known to be dysregulated in PC, in this study we investigated the functional consequences of combined dysregulation of PKD1 and E-cadherin using a panel of human PC cell lines. Gain and loss of function studies were carried out by either transfecting PC cells with full-length E-cadherin and/or PKD1 cDNA or by protein silencing by siRNAs, respectively. We studied major malignant phenotypic characteristics including cell proliferation, motility, and invasion at the cellular level, which were corroborated with appropriate changes in representative molecular markers. Down regulation or ectopic expression of either E-cadherin or PKD1 significantly increased or decreased cell proliferation, motility, and invasion, respectively, and combined down regulation cumulatively influenced the effects. Loss of PKD1 or E-cadherin expression was associated with increased expression of the pro-survival molecular markers survivin, beta-catenin, cyclin-D, and c-myc, whereas overexpression of PKD1 and/or E-cadherin resulted in an increase of caspases. The inhibitory effect of PKD1 and E-cadherin on cell proliferation was rescued by coexpression with beta-catenin, suggesting that beta-catenin mediates the effect of proliferation by PKD1 and E-cadherin. This study establishes the functional significance of combined dysregulation of PKD1 and E-cadherin in PC and that their effect on cell growth is mediated by beta-catenin.

    Funded by: NCI NIH HHS: R03 CA121351-02

    Journal of cellular biochemistry 2008;104;1;82-95

  • N-glycosylation affects the adhesive function of E-Cadherin through modifying the composition of adherens junctions (AJs) in human breast carcinoma cell line MDA-MB-435.

    Zhao H, Liang Y, Xu Z, Wang L, Zhou F, Li Z, Jin J, Yang Y, Fang Z, Hu Y, Zhang L, Su J and Zha X

    Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, 138 Yi Xue Yuan Road, Shanghai 200032, PR China.

    E-cadherin mediates calcium-dependent cell-cell adhesion between epithelial cells. The ectodomain of human E-cadherin contains four potential N-glycosylation sites at Asn residues 554, 566, 618, and 633. In this study, the role of N-glycosylation in E-cadherin-mediated cell-cell adhesion was investigated by site-directed mutagenesis. In MDA-MB-435 cells, all four potential N-glycosylation sites of human E-cadherin were N-glycosylated. Removal of N-glycan at Asn-633 dramatically affected E-cadherin stability. In contrast, mutant E-cadherin lacking the other three N-glycans showed similar protein stability in comparison with wild-type E-cadherin. Moreover, N-glycans at Asn-554 and Asn-566 were found to affect E-cadherin-mediated calcium-dependent cell-cell adhesion, and removal of either of the two N-glycans caused a significant decrease in calcium-dependent cell-cell adhesion accompanied with elevated cell migration. Analysis of the composition of adherens junctions (AJs) revealed that removal of N-glycans on E-cadherin resulted in elevated tyrosine phosphorylation level of beta-catenin and reduced beta- and alpha-catenins at AJs. These findings demonstrate that N-glycosylation may affect the adhesive function of E-cadherin through modifying the composition of AJs.

    Journal of cellular biochemistry 2008;104;1;162-75

  • Cell-type-specific function of BCL9 involves a transcriptional activation domain that synergizes with beta-catenin.

    Sustmann C, Flach H, Ebert H, Eastman Q and Grosschedl R

    Max Planck Institute of Immunobiology, Department of Cellular and Molecular Immunology, 79108 Freiburg, Germany. grosschedl@immunbio.mpg.de.

    Transcriptional regulation by the canonical Wnt pathway involves the stabilization and nuclear accumulation of beta-catenin, which assembles with LEF1/TCF transcription factors and cofactors to activate Wnt target genes. Recently, the nuclear beta-catenin complex has been shown to contain BCL9, which interacts with beta-catenin and recruits Pygopus as a transcriptional coactivator. However, the presumed general functions of Pygopus and BCL9, which has been proposed to act as a scaffolding protein for Pygopus, have been challenged by the rather specific and modest developmental defects of targeted inactivations of both the Pygo1 and the Pygo2 genes. Here, we analyze the function of BCL9 in transcriptional activation by beta-catenin. We find that BCL9 acts in a cell-type-specific manner and, in part, independent of Pygopus. We show that BCL9 itself contains a transcriptional activation domain in the C terminus, which functionally synergizes in lymphoid cells with the C-terminal transactivation domain of beta-catenin. Finally, we identify amino acids in the transactivation domain of beta-catenin that are important for its function and association with the histone acetyltransferases CBP/p300 and TRRAP/GCN5. Thus, BCL9 may serve to modulate and diversify the transcriptional responses to Wnt signaling in a cell-type-specific manner.

    Molecular and cellular biology 2008;28;10;3526-37

  • Characterization of bipotential epidermal progenitors derived from human sebaceous gland: contrasting roles of c-Myc and beta-catenin.

    Lo Celso C, Berta MA, Braun KM, Frye M, Lyle S, Zouboulis CC and Watt FM

    Massachusetts General Hospital, Center for Regenerative Medicine, Boston, Massachusetts, USA.

    The current belief is that the epidermal sebaceous gland (SG) is maintained by unipotent stem cells that are replenished by multipotent stem cells in the hair follicle (HF) bulge. However, sebocytes can be induced by c-Myc (Myc) activation in interfollicular epidermis (IFE), suggesting the existence of bipotential stem cells. We found that every SZ95 immortalized human sebocyte that underwent clonal growth in culture generated progeny that differentiated into both sebocytes and cells expressing involucrin and cornifin, markers of IFE and HF inner root sheath differentiation. The ability to generate involucrin positive cells was also observed in a new human sebocyte line, Seb-E6E7. SZ95 xenografts differentiated into SG and IFE but not HF. SZ95 cells that expressed involucrin had reduced Myc levels; however, this did not correlate with increased expression of the Myc repressor Blimp1, and Blimp1 expression did not distinguish cells undergoing SG, IFE, or HF differentiation in vivo. Overexpression of Myc stimulated sebocyte differentiation, whereas overexpression of beta-catenin stimulated involucrin and cornifin expression. In transgenic mice simultaneous activation of Myc and beta-catenin revealed mutual antagonism: Myc blocked ectopic HF formation and beta-catenin reduced SG differentiation. Overexpression of the Myc target gene Indian hedgehog did not promote sebocyte differentiation in culture and cyclopamine treatment, while reducing proliferation, did not block Myc induced sebocyte differentiation in vivo. Our studies provide evidence for a bipotential epidermal stem cell population in an in vitro model of human epidermal lineage selection and highlight the importance of Myc as a regulator of sebocyte differentiation.

    Funded by: Cancer Research UK; Medical Research Council: G0500502; NCI NIH HHS: CA-118916

    Stem cells (Dayton, Ohio) 2008;26;5;1241-52

  • Ethanol may suppress Wnt/beta-catenin signaling on human bone marrow stroma cells: a preliminary study.

    Yeh CH, Chang JK, Wang YH, Ho ML and Wang GJ

    Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.

    Ethanol and glucocorticoids are risk factors associated with osteonecrosis. Previous reports suggest ethanol and glucocorticoids induce adipogenesis, decrease osteogenesis in bone marrow stroma cells, and produce intracellular lipid deposits resulting in death of osteocytes. The Wnt/beta-catenin signal pathway is involved in the regulation of homeostasis of bone and we presume glucocorticoids and ethanol may induce osteonecrosis in humans through a similar mechanism as in rodents. We hypothesized (1) ethanol, like glucocorticoids, decreases osteogenesis and increases adipogenesis through the Wnt/beta-catenin signaling pathway in human bone marrow stromal cells; and (2) ethanol decreases intranuclear translocation of beta-catenin. We found both dexamethasone and ethanol decrease the gene and protein expression of osteogenesis and increase that of adipogenesis through Wnt signaling-related genes by semiquantitative and quantitative polymerase chain reaction and Western blot. Ethanol hampered intranuclear translocation of beta-catenin by immunofluorescence analysis. The data suggest the Wnt/beta-catenin signaling pathway may be associated with ethanol-induced osteonecrosis.

    Clinical orthopaedics and related research 2008;466;5;1047-53

  • Evaluation of beta-catenin activating mutations in chronic myeloid leukemia.

    Chomel JC, Villalva C, Sorel N, Chazelas F, Guilhot F and Turhan AG

    Leukemia research 2008;32;5;838-9

  • KIT regulates tyrosine phosphorylation and nuclear localization of beta-catenin in mast cell leukemia.

    Kajiguchi T, Lee S, Lee MJ, Trepel JB and Neckers L

    Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1107, United States.

    Gain-of-function mutations in the proto-oncogene c-kit that induce constitutive kinase activity of its product, KIT protein, are characteristic of human mast cell disease and are believed to play a central role in mast cell leukemia oncogenesis, proliferation and survival. Nuclear overexpression of the Wnt effector beta-catenin and deregulated beta-catenin nuclear signaling can promote malignant transformation in solid tumors and hematologic malignancies. However, a role for beta-catenin in mast cell leukemia has not been described. Nuclear accumulation of beta-catenin is upregulated by its tyrosine phosphorylation, a process that can be exacerbated by deregulated expression of oncogenic tyrosine kinases. Here, we investigated the relationship between activated KIT and beta-catenin signaling in mast cell leukemia. Beta-catenin was tyrosine-phosphorylated in cells with KIT activated by either gain-of-function mutation or incubation with the KIT ligand stem cell factor. Beta-catenin tyrosine phosphorylation depended on KIT activity but not on PI3K-AKT activation. Tyrosine phosphorylation of beta-catenin was associated with its nuclear localization and enhanced transcription of target genes c-myc and cyclin D1. Endogenous KIT and beta-catenin were found to associate in mast cell leukemia cells, and in vitro kinase assay demonstrated that active KIT phosphorylates tyrosine residues of beta-catenin directly. Aberrant beta-catenin-driven transcription caused by deregulated KIT may represent a significant new target for treatment of mast cell leukemia.

    Funded by: NCI NIH HHS: Z01 SC010074-12, Z99 CA999999

    Leukemia research 2008;32;5;761-70

  • PTPRK negatively regulates transcriptional activity of wild type and mutated oncogenic beta-catenin and affects membrane distribution of beta-catenin/E-cadherin complexes in cancer cells.

    Novellino L, De Filippo A, Deho P, Perrone F, Pilotti S, Parmiani G and Castelli C

    Unit of Immunotherapy of Human Tumors, Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

    Previous reports showed that receptor-type protein-tyrosine phosphatase PTPRK co-localizes with beta-catenin at adherens junctions, and in vitro experiments suggested that beta-catenin could be substrate of PTPRK-mediated phosphatase activity. beta-catenin is a molecule endowed with a dual function being involved both in cell adhesion and in Wnt signaling pathway. Here we provide evidence for the role of PTPRK in negatively regulating the beta-catenin transcriptional activity by modulating its intracellular and membrane distribution. Expression of PTPRK protein in HEK293 cells and in PTPRK-null melanoma cell lines, one of which harbors a mutated oncogenic beta-catenin, impairs nuclear accumulation of wild type and oncogenic forms of beta-catenin, limits cytosolic levels of tyrosine-phosphorylated beta-catenin, and leads to re-localization of E-cadherin/beta-catenin complexes in ordered membrane phase along cell-cell contacts. This re-modulation of beta-catenin cellular distribution results in the inhibition of cyclin D1 and c-myc protein expression, whose genes are targets of beta-catenin. Tumor cells upon re-expression of PTPRK have a reduced proliferative and migration capacity. Moreover we show that PTPRK is also active in negatively regulating the transactivating function of beta-catenin in normal melanocytes as confirmed by experiments with silenced PTPRK by specific siRNA. Our data show that PTPRK influences transactivating activity of beta-catenin in non-tumoral and neoplastic cells by regulating the balance between signaling and adhesive beta-catenin, thus providing biochemical basis for the hypothesis of PTPRK as a tumor suppressor gene.

    Cellular signalling 2008;20;5;872-83

  • Reduced membranous beta-catenin protein expression is associated with metastasis and poor prognosis in squamous cell carcinoma of the esophagus.

    Hsu PK, Li AF, Wang YC, Hsieh CC, Huang MH, Hsu WH and Hsu HS

    Division of Thoracic Surgery, Department of Surgery, Taipei Veterans General Hospital, National Yang-Ming University, School of Medicine, Taipei, Taiwan.

    Objectives: The aim of this study was to evaluate, by immunohistochemical analysis, the protein expression of beta-catenin and p53 in resected esophageal squamous cell carcinoma specimens. The clinical relevance and prognostic significance of the expression of these proteins were also analyzed.

    Methods: Immunohistochemistry was performed on paraffin-embedded tissue specimens from 68 resected esophageal squamous cell carcinoma tumor specimens to detect the expression of beta-catenin and p53. The correlation between the results of immunoexpression and the clinicopathologic parameters and patient survival was processed statistically.

    Results: Reduced membranous beta-catenin expression was noted in 43 (63.2%) of 68 tumor specimens. Increased expression of p53 was observed in 43 (63.2%) of 68 specimens. Reduced membranous beta-catenin protein expression was associated with the presence of distant metastasis (P = .006). Patients with reduced membranous beta-catenin expression had a worse prognosis than patients with normal membranous beta-catenin expression (P = .005). Patients with combined increased p53 and reduced membranous beta-catenin protein expression had the worst prognosis (P = .012). In a multivariate survival analysis, reduced membranous beta-catenin expression and nodal involvement were independent prognostic factors (P = .004 and .019, respectively).

    Conclusions: Immunohistochemical analysis revealed that reduced membranous beta-catenin protein expression was associated with the presence of distant metastasis and a poor prognosis in patients with esophageal squamous cell carcinoma. Combined increased p53 and reduced membranous beta-catenin protein expression indicated a very poor prognosis in patients with esophageal squamous cell carcinoma. Further investigation is needed to understand the roles of beta-catenin and p53 in the tumorigenesis and metastasis of esophageal squamous cell carcinoma.

    The Journal of thoracic and cardiovascular surgery 2008;135;5;1029-35

  • Cutaneous cancer stem cell maintenance is dependent on beta-catenin signalling.

    Malanchi I, Peinado H, Kassen D, Hussenet T, Metzger D, Chambon P, Huber M, Hohl D, Cano A, Birchmeier W and Huelsken J

    Ecole Polytechnique Fédérale de Lausanne/ISREC (Swiss Institute for Experimental Cancer Research) and National Center of Competence in Research Molecular Oncology, Chemin des Boveresses 155, 1066 Epalinges, Switzerland.

    Continuous turnover of epithelia is ensured by the extensive self-renewal capacity of tissue-specific stem cells. Similarly, epithelial tumour maintenance relies on cancer stem cells (CSCs), which co-opt stem cell properties. For most tumours, the cellular origin of these CSCs and regulatory pathways essential for sustaining stemness have not been identified. In murine skin, follicular morphogenesis is driven by bulge stem cells that specifically express CD34. Here we identify a population of cells in early epidermal tumours characterized by phenotypic and functional similarities to normal bulge skin stem cells. This population contains CSCs, which are the only cells with tumour initiation properties. Transplants derived from these CSCs preserve the hierarchical organization of the primary tumour. We describe beta-catenin signalling as being essential in sustaining the CSC phenotype. Ablation of the beta-catenin gene results in the loss of CSCs and complete tumour regression. In addition, we provide evidence for the involvement of increased beta-catenin signalling in malignant human squamous cell carcinomas. Because Wnt/beta-catenin signalling is not essential for normal epidermal homeostasis, such a mechanistic difference may thus be targeted to eliminate CSCs and consequently eradicate squamous cell carcinomas.

    Nature 2008;452;7187;650-3

  • A cryptic frizzled module in cell surface collagen 18 inhibits Wnt/beta-catenin signaling.

    Quélard D, Lavergne E, Hendaoui I, Elamaa H, Tiirola U, Heljasvaara R, Pihlajaniemi T, Clément B and Musso O

    INSERM, U620, University of Rennes-1, Rennes, France.

    Collagens contain cryptic polypeptide modules that regulate major cell functions, such as cell proliferation or death. Collagen XVIII (C18) exists as three amino terminal end variants with specific amino terminal polypeptide modules. We investigated the function of the variant 3 of C18 (V3C18) containing a frizzled module (FZC18), which carries structural identity with the extracellular cysteine-rich domain of the frizzled receptors. We show that V3C18 is a cell surface heparan sulfate proteoglycan, its topology being mediated by the FZC18 module. V3C18 mRNA was expressed at low levels in 21 normal adult human tissues. Its expression was up-regulated in fibrogenesis and in small well-differentiated liver tumors, but decreased in advanced human liver cancers. Low FZC18 immunostaining in liver cancer nodules correlated with markers of high Wnt/beta-catenin activity. V3C18 (M(r) = 170 kD) was proteolytically processed into a cell surface FZC18-containing 50 kD glycoprotein precursor that bound Wnt3a in vitro through FZC18 and suppressed Wnt3a-induced stabilization of beta-catenin. Ectopic expression of either FZC18 (35 kD) or its 50 kD precursor inhibited Wnt/beta-catenin signaling in colorectal and liver cancer cell lines, thus downregulating major cell cycle checkpoint gatekeepers cyclin D1 and c-myc and reducing tumor cell growth. By contrast, full-length V3C18 was unable to inhibit Wnt signaling. In summary, we identified a cell-surface signaling pathway whereby FZC18 inhibits Wnt/beta-catenin signaling. The signal, encrypted within cell-surface C18, is released by enzymatic processing as an active frizzled cysteine-rich domain (CRD) that reduces cancer cell growth. Thus, extracellular matrix controls Wnt signaling through a collagen-embedded CRD behaving as a cell-surface sensor of proteolysis, conveying feedback cues to control cancer cell fate.

    PloS one 2008;3;4;e1878

  • Disturbed expression of E-cadherin, beta-catenin and tight junction proteins in colon carcinoma is unrelated to growth pattern and genetic polymorphisms.

    Hahn-Strömberg V, Edvardsson H, Bodin L and Franzén L

    Dept. of Clinical Medicine, Orebro University, Orebro, Orebro, Sweden. victoria.hahn-stromberg@orebroll.se

    Adhesion proteins are responsible for the structural integrity of epithelial tissue and in tumors this integrity is often lost, resulting in a disorganization of the tissue. In the present study the complexity of the invasive front of colon carcinomas was correlated with cell adhesion protein expression and with polymorphisms in their genes. A complexity index was constructed from 32 colon carcinomas using computer-assisted morphometry estimating fractal dimension and tumor cell clusters followed by tree analysis. Immunohistochemical staining of beta-catenin, E-cadherin, occludin and claudin 2 was used for assessment of protein expression. Genetic screening of tissue from the tumor invasion front with laser microdissection was performed using SSCP and DNA sequencing. Adhesion protein distribution was significantly disturbed in most carcinomas. A single mutation in the gene of beta-catenin was found but there was no correlation between protein expression and genetic polymorphism. Nor was there any correlation between the complexity of the invasive border and protein distribution or genetic alterations. The results indicate that the complexity of colon carcinoma invasion is not dependent on genetic derangements in the genes of adhesion proteins or the protein distribution. Rather, aberrations in the function of other proteins related to the adhesive proteins could be responsible.

    APMIS : acta pathologica, microbiologica, et immunologica Scandinavica 2008;116;4;253-62

  • Modulation of beta-catenin and E-cadherin interaction by Vpu increases human immunodeficiency virus type 1 particle release.

    Salim A and Ratner L

    Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA.

    Vpu (viral protein U) is a 17-kDa human immunodeficiency virus type 1 (HIV-1) accessory protein that enhances the release of particles from the surfaces of infected cells. Vpu recruits beta-transducin repeat-containing protein (beta-TrCP) and mediates proteasomal degradation of CD4. By sequestering beta-TrCP away from other cellular substrates, Vpu leads to the stabilization of beta-TrCP substrates such as beta-catenin, IkappaBalpha, ATF4, and Cdc25A, but not of other substrates such as Emi1. This study shows that in addition to stabilizing beta-catenin, Vpu leads to the depression of both total and beta-catenin-associated E-cadherin levels through beta-TrCP-dependent stabilization of the transcriptional repressor Snail. We showed that both downregulation of overall E-cadherin levels and dissociation of E-cadherin from beta-catenin result in enhanced viral release. By contrast, the overexpression of E-cadherin or the prevention of the dissociation of E-cadherin from beta-catenin results in depressed levels of virus release. Since E-cadherin is expressed only in dendritic cells and macrophages, and not in T cells, our data suggest that the HIV-1 vpu gene may have evolved to counteract different restrictions to assembly in different cells.

    Funded by: NIAID NIH HHS: AI24745, R01 AI024745

    Journal of virology 2008;82;8;3932-8

  • Peroxisome proliferator-activated receptor gamma (PPARgamma) suppresses colonic epithelial cell turnover and colon carcinogenesis through inhibition of the beta-catenin/T cell factor (TCF) pathway.

    Fujisawa T, Nakajima A, Fujisawa N, Takahashi H, Ikeda I, Tomimoto A, Yonemitsu K, Nakajima N, Kudo C, Wada K, Kubota N, Terauchi Y, Kadowaki T, Nakagama H and Blumberg RS

    Division of Gastroenterology, Yokohama City University School of Medicine, Kanazawa-ku, Yokohama, Japan.

    Peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor superfamily member, plays a major role in lipid metabolism and insulin sensitivity. We investigated the role of PPARgamma in colonic epithelial cell turnover and carcinogenesis in colon because PPARgamma is strongly expressed in colonic epithelium. Administration of PPARgamma agonists suppressed epithelial cell turnover in mice. Expression level of beta-catenin protein, a key molecule in carcinogenesis, was increased in mouse colon treated with PPARgamma ligands. A direct interaction between beta-catenin and PPARgamma in cultured cell lines and colonic epithelium in mice was observed. Ligand-activated PPARgamma ligand directly interacts with beta-catenin, retaining it in the cytosol and reducing beta-catenin/T cell factor (TCF) transcriptional activity that is functionally important on aberrant crypt foci (ACF) formation. PPARgamma hetero-deficiency promoted the induction of ACF, but had no effect on the incidence of colonic polyps. These results indicate that PPARgamma regulates colonic epithelial cell turnover via direct interactions with beta-catenin, resulting in inhibition of beta-catenin-mediated transcriptional pathways that are involved in promoting cell proliferation. Our findings suggest that PPARgamma plays a role as a physiological regulator of colonic epithelial cell turnover and consequently predisposition to the development of colon cancer in early stage.

    Funded by: NIDDK NIH HHS: DK44319, DK51362, DK53056

    Journal of pharmacological sciences 2008;106;4;627-38

  • Utility of thin-layer preparations in endometrial cytology: immunocytochemical expression of PTEN, beta-catenin and p53 for benign endometrial lesions.

    Norimatsu Y, Miyamoto T, Kobayashi TK, Oda T, Moriya T, Yanoh K, Miyake Y and Ohno E

    Department of Pathology, Kurashiki Central Hospital, Kurashiki, Japan.

    This article focuses on the characteristic features of morphology and molecular biology of PTEN, beta-catenin, and p53 immunocytochemistry in normal endometrium (proliferative, secretory, and atrophic) and endometrial glandular and stromal breakdown (EGBD) using thin-layer specimens. During a 6-month period, 120 endometrial samples were collected directly using the Uterobrush and a thin-layer specimen was prepared. Immunocytochemical expression of PTEN, beta-catenin, and p53 were investigated using 30 cases each of proliferative endometrium (PE), secretory endometrium (SE), atrophic endometrium (AE), and EGBD.PTEN expression of normal endometrial glandular epithelial cells changes with the hormonal status; PE produce very high expression, SE creates attenuation or disappearance of PTEN expression and AE diminished more in comparison with SE. PTEN expression of EGBD showed a tendency towards attenuation compared with PE, but showed high expression in comparison with SE and AE. As for the immunoreactivity of beta-catenin, in all phases (PE, SE, AE, and EGBD), it was observed in the cytoplasm of glandular epithelial cells, but not nuclei, and showed strong membranous staining. As for the p53 immunoreactivity, p53 positivity was not observed in the glandular epithelial cells in all phases (PE, SE, AE, and EGBD) with the exception of some metaplastic cells. The presence of p53 immunoreactivity of a weak, low ratio in metaplastic cells was unexpected. In the current study, the expression manner of PTEN, beta-catenin, and p53 immunocytochemistry was observed in the normal endometrium (PE, SE, and AE) and EGBD.

    Diagnostic cytopathology 2008;36;4;216-23

  • Mutations in components of the Wnt signaling pathway in gastric cancer.

    Pan KF, Liu WG, Zhang L, You WC and Lu YY

    Department of Cancer Epidemiology, Peking University School of Oncology and Beijing Cancer Hospital & Institute, Beijing, China.

    Aim: To explore the contribution of AXIN1, AXIN2 and beta-catenin, components of Wnt signaling pathway, to the carcinogenesis of gastric cancer (GC), we examined AXIN1, AXIN2 exon7 and CTNNB1 (encoding beta-catenin) exon3 mutations in 70 GCs.

    Methods: The presence of mutations was identified by polymerase chain reaction (PCR)-based denaturing high-performance liquid chromatography and direct DNA sequencing. Beta-catenin expression was detected by immunohistochemical analysis.

    Results: Among the 70 GCs, 5 (7.1%) had mutations in one or two of these three components. A frameshift mutation (1 bp deletion) in exon7 of AXIN2 was found in one case. Four cases, including the case with a mutation in AXIN2, had frameshift mutations and missense mutations in AXIN1. Five single nucleotide polymorphisms (SNPs), 334 C>T, 874 C>T, 1396 G>A, 1690 C>T and 1942 T>G, were identified in AXIN1. A frameshift mutation (27 bp deletion) spanning exon3 of CTNNB1 was observed in one case. All four cases with mutations in AXIN1 and AXIN2 showed nuclear beta-catenin expression.

    Conclusion: These data indicate that the mutations in AXIN1 and AXIN2 may contribute to gastric carcino-genesis.

    World journal of gastroenterology : WJG 2008;14;10;1570-4

  • Differential effect of NF-kappaB activity on beta-catenin/Tcf pathway in various cancer cells.

    Cho HH, Song JS, Yu JM, Yu SS, Choi SJ, Kim DH and Jung JS

    Department of Physiology, School of Medicine, Pusan National University, Suh-Gu, Pusan, Republic of Korea.

    beta-Catenin/Tcf and NF-kappaB pathways play an important role in biological functions. We determined the underlying mechanisms of differential interaction between two pathways in various human cancer cell lines. NF-kappaB positively regulated beta-catenin/Tcf pathways in human glioblastoma, whereas it has an opposite effect on beta-catenin/Tcf pathways in colon, liver, and breast cancer cells. Expression of lucine zipper tumor suppressor 2 (lzts2) was positively regulated by NF-kappaB activity in colon, liver, and breast cancer cells, whereas negatively regulated in glioma cells. Downregulation of lzts2 increased the beta-catenin/Tcf promoter activity and inhibited NF-kappaB-induced modulation of the nuclear translocation of beta-catenin. These data indicate that the differential crosstalk between beta-catenin/Tcf and NF-kappaB pathway in various cancer cells is resulted from the differences in the regulation of NF-kappaB-induced lzts2 expression.

    FEBS letters 2008;582;5;616-22

  • A novel RET kinase-beta-catenin signaling pathway contributes to tumorigenesis in thyroid carcinoma.

    Gujral TS, van Veelen W, Richardson DS, Myers SM, Meens JA, Acton DS, Duñach M, Elliott BE, Höppener JW and Mulligan LM

    Division of Cancer Biology and Genetics, Cancer Research Institute, Queen's University, Kingston, Ontario, Canada.

    The RET receptor tyrosine kinase has essential roles in cell survival, differentiation, and proliferation. Oncogenic activation of RET causes the cancer syndrome multiple endocrine neoplasia type 2 (MEN 2) and is a frequent event in sporadic thyroid carcinomas. However, the molecular mechanisms underlying RET's potent transforming and mitogenic signals are still not clear. Here, we show that nuclear localization of beta-catenin is frequent in both thyroid tumors and their metastases from MEN 2 patients, suggesting a novel mechanism of RET-mediated function through the beta-catenin signaling pathway. We show that RET binds to, and tyrosine phosphorylates, beta-catenin and show that the interaction between RET and beta-catenin can be direct and independent of cytoplasmic kinases, such as SRC. As a result of RET-mediated tyrosine phosphorylation, beta-catenin escapes cytosolic down-regulation by the adenomatous polyposis coli/Axin/glycogen synthase kinase-3 complex and accumulates in the nucleus, where it can stimulate beta-catenin-specific transcriptional programs in a RET-dependent fashion. We show that down-regulation of beta-catenin activity decreases RET-mediated cell proliferation, colony formation, and tumor growth in nude mice. Together, our data show that a beta-catenin-RET kinase pathway is a critical contributor to the development and metastasis of human thyroid carcinoma.

    Cancer research 2008;68;5;1338-46

  • Active beta-catenin signaling is an inhibitory pathway for human immunodeficiency virus replication in peripheral blood mononuclear cells.

    Kumar A, Zloza A, Moon RT, Watts J, Tenorio AR and Al-Harthi L

    Rush University Medical Center, Department of Immunology/Microbiology, 1735 W. Harrison Street, 614 Cohn, Chicago, IL 60612, USA.

    The Wnt/beta-catenin pathway is involved in cell functions governing development and disease. In modeling postentry restriction of human immunodeficiency virus (HIV) replication in astrocytes, we reported that part of this natural resistance to productive replication of HIV in astrocytes involved expression of proteins of the Wnt/beta-catenin signaling pathway. We determined here whether induction of beta-catenin signaling in peripheral blood mononuclear cells (PBMCs) can modulate HIV replication. Given that lithium is an inducer of beta-catenin signaling, we used it as a tool to determine the impact of beta-catenin signaling on HIV replication in PBMCs. We demonstrated that lithium inhibited the replication of T-tropic and primary isolates of HIV by >90% and did so in noncytotoxic/noncytostatic concentrations and in a beta-catenin-dependent manner. Specifically, inhibiting beta-catenin signaling by transfection of dominant-negative mutant constructs to either T-cell factor 4, the downstream effector of Wnt signaling, or beta-catenin, the central mediator of this pathway, abrogated the ability of lithium to inhibit HIV replication. Moreover, when Wnt/beta-catenin signaling was inhibited, the level of HIV replication was enhanced by fourfold. To confirm the in vivo relevance of the beta-catenin pathway in repressing HIV replication, we evaluated HIV-positive antiretroviral therapy-naive patients who were on lithium therapy. These patients demonstrated a reduction in viral load, which increased as the dose of lithium was reduced. Collectively, these data indicate that beta-catenin signaling is an intrinsic molecular pathway restricting HIV replication in PBMCs.

    Journal of virology 2008;82;6;2813-20

  • Crossregulation of beta-catenin/Tcf pathway by NF-kappaB is mediated by lzts2 in human adipose tissue-derived mesenchymal stem cells.

    Hyun Hwa Cho, Hye Joon Joo, Ji Sun Song, Yong Chan Bae and Jin Sup Jung

    Department of Physiology, School of Medicine, Pusan National University, Pusan (602-739), Korea.

    beta-catenin/Tcf and NF-kappaB signaling pathways play an important role in biological functions and crosstalk between these pathways has been reported. We found that the modulation of NF-kappaB activity showed a direct correlation with beta-catein/Tcf pathway in human adipose tissue (hASCs) and bone marrow (hBMSCs)-derived mesenchymal stem cells. Expression of lzts2, which inhibits nuclear translocation of beta-catenin and its transactivation activity, was regulated by NF-kappaB activity. Downregulation of lzts2 by RNA interference increased the nuclear translocation of beta-catenin and NF-kappaB activity in hASCs. NF-kappaB activation by the downregulation of lzts2 was accompanied by the increase of beta-TrCP1 expression and the decrease of IkappaB level. Downregulation of lzts2 increased the proliferation of hASCs and hBMSC, and blocked the NF-kappaB inhibitor-induced inhibitory effect on their proliferation and Tcf promoter activation. These findings provide the first evidence that the reciprocal crosstalk between beta-catenin/Tcf pathway and NF-kappaB signaling in hMSCs is mediated through the regulation of lzts2 expression.

    Biochimica et biophysica acta 2008;1783;3;419-28

  • Crystal structure of a full-length beta-catenin.

    Xing Y, Takemaru K, Liu J, Berndt JD, Zheng JJ, Moon RT and Xu W

    Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98195, USA.

    beta-catenin plays essential roles in cell adhesion and Wnt signaling, while deregulation of beta-catenin is associated with multiple diseases including cancers. Here, we report the crystal structures of full-length zebrafish beta-catenin and a human beta-catenin fragment that contains both the armadillo repeat and the C-terminal domains. Our structures reveal that the N-terminal region of the C-terminal domain, a key component of the C-terminal transactivation domain, forms a long alpha helix that packs on the C-terminal end of the armadillo repeat domain, and thus forms part of the beta-catenin superhelical core. The existence of this helix redefines our view of interactions of beta-catenin with some of its critical partners, including ICAT and Chibby, which may form extensive interactions with this C-terminal domain alpha helix. Our crystallographic and NMR studies also suggest that the unstructured N-terminal and C-terminal tails interact with the ordered armadillo repeat domain in a dynamic and variable manner.

    Funded by: Howard Hughes Medical Institute; NCI NIH HHS: CA 90351, R01 CA090351; NIGMS NIH HHS: R01 GM081492-02

    Structure (London, England : 1993) 2008;16;3;478-87

  • Frequent beta-catenin nuclear labeling in sessile serrated polyps of the colorectum with neoplastic potential.

    Wu JM, Montgomery EA and Iacobuzio-Donahue CA

    Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.

    We obtained 22 sessile serrated adenomas (SSAs) and 19 hyperplastic polyps (HPs) and performed immunolabeling for cytokeratins (CKs) 7 and 20, CDX2, beta-catenin, and p53 to determine the role of these markers in aiding distinction of lesions with neoplastic potential. Patients with SSAs more frequently had a prior or coexistent tubular adenoma (P = .004) that was right-sided (P = .00001) and larger (P = .03). No difference in CK7, CK20, or p53 labeling was found after correction for colonic location. However, CDX2 labeling was significantly lower in SSAs (P = .02) and was predominantly confined to the crypt bases, whereas it was diffusely positive in HPs (P < .001). Surprisingly, aberrant nuclear labeling for beta-catenin was found in 9 (41%) of the SSAs but in none of the HPs (P < .002). We propose that beta-catenin and/or CDX2 immunolabeling may have diagnostic usefulness in the evaluation of serrated polyps. These findings also suggest that Wnt signaling has a role in SSA development.

    Funded by: NCI NIH HHS: CA106610

    American journal of clinical pathology 2008;129;3;416-23

  • Frequent nuclear expression of beta-catenin protein but rare beta-catenin mutation in pulmonary sclerosing haemangioma.

    Chiang PM, Yuan RH, Hsu HC, Mao TL, Hu RH, Lai PL and Jeng YM

    Department of Pathology, National Taiwan University Hospital, and College of Medicine, National Taiwan University, Taipei, Taiwan.

    Background: Pulmonary sclerosing haemangioma (PSH) is an uncommon tumour that is composed of glandular/papillary lining cells and polygonal cells. The biological behaviour of this tumour has been investigated; however, the molecular pathogenesis of PSH remains unknown.

    Aims: To characterise the role of the Wnt/beta-catenin pathway in the genesis of PSH.

    Methods: 37 PSH samples were investigated immunohistochemically for detection of the beta-catenin protein and direct sequencing of exon 3 of the beta-catenin gene.

    Results: Nuclear expression of beta-catenin was found in the lining component of 23 tumours (62%) and in the polygonal component of 11 tumours (30%). The expression of beta-catenin was stronger in the lining component, but weaker in the polygonal component. Interestingly, all the tumours with expression of beta-catenin in the polygonal component also expressed beta-catenin in the lining component. However, mutation of exon 3 of the beta-catenin gene was detected in only one tumour that expressed nuclear beta-catenin in lining and polygonal components.

    Conclusions: The Wnt/beta-catenin pathway is involved in the genesis of PSH, but mutation of exon 3 of the beta-catenin gene rarely contributes to the activation of the Wnt/beta-catenin pathway in PSH.

    Journal of clinical pathology 2008;61;3;268-71

  • Somatic FGF9 mutations in colorectal and endometrial carcinomas associated with membranous beta-catenin.

    Abdel-Rahman WM, Kalinina J, Shoman S, Eissa S, Ollikainen M, Elomaa O, Eliseenkova AV, Bützow R, Mohammadi M and Peltomäki P

    Department of Medical Genetics, University of Helsinki, Helsinki, Finland. Wael.Abdel-Rahman@helsinki.fi

    We previously described striking molecular features including high frequency of membranous beta-catenin in subsets of familial colon cancers with as yet unknown predisposition. We hypothesized that such tumors might carry mutations in Wnt/beta-catenin target genes. Fibroblast growth factor 9 (FGF9) was an attractive target, as it maps to a common area of loss of heterozygosity (LOH) in colorectal carcinomas on 13q12.11. Here, we report, for the first time, the occurrence of FGF9 mutations in human cancers. We found a total of six distinct FGF9 mutations including one frameshift, four missense, and one nonsense, in 10 (six colorectal and four endometrial) out of 203 tumors and cell lines. The frameshift mutation was detected in five different tumors. Mapping of these mutations onto the crystal structure of FGF9 predicted that they should all lead to loss of function albeit through variable mechanisms. The p.R173K mutation should diminish ligand affinity for heparin/heparan sulfate, the p.V192M, p.D203G, and p.L188YfsX18 (FGF9(Delta205-208)) mutations should negatively impact ligand's interaction with receptor, while p.G84E and p.E142X (FGF9(Delta142-208)) mutations should interfere with ligand folding. Consistent with these structural predictions, the p.V192M, p.D203G, and p.L188YfsX18 (FGF9(Delta205-208)) mutations impaired the ability of ligand to activate mitogen-activated protein kinase (MAPK) cascade in cultured cells expressing FGF receptors. LOH was observed in seven out of nine FGF9 mutant tumors, supporting the predicted loss of function. Interestingly, eight out of 10 (80%) of the FGF9 mutant tumors showed normal membranous beta-catenin expression and the absence of mutation in the beta-catenin gene (CTNNB1). These data suggest that FGF9 plays a role in colorectal and endometrial carcinogenesis.

    Funded by: NIDCR NIH HHS: DE13686

    Human mutation 2008;29;3;390-7

  • Deregulated Wnt/beta-catenin program in high-risk neuroblastomas without MYCN amplification.

    Liu X, Mazanek P, Dam V, Wang Q, Zhao H, Guo R, Jagannathan J, Cnaan A, Maris JM and Hogarty MD

    Division of Oncology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104-4318, USA.

    Neuroblastoma (NB) is a frequently lethal tumor of childhood. MYCN amplification accounts for the aggressive phenotype in a subset while the majority have no consistently identified molecular aberration but frequently express MYC at high levels. We hypothesized that activated Wnt/beta-catenin (CTNNB1) signaling might account for this as MYC is a beta-catenin transcriptional target and multiple embryonal and neural crest malignancies have oncogenic alterations in this pathway. NB cell lines without MYCN amplification express higher levels of MYC and beta-catenin (with aberrant nuclear localization) than MYCN-amplified cell lines. Evidence for aberrant beta-catenin-TCF transcriptional activity was demonstrated using expression profiles from 73 primary NBs. Findings included increased WNT ligands (WNT1, WNT6, WNT7A, WNT10B), DVL1 and TCF7 expression in high-risk NBs without MYCN amplification, consistent with canonical beta-catenin signaling. More directly, Patterns of Gene Expression and Gene Set Enrichment Analyses demonstrated beta-catenin target genes (for example, MYC, PPARD, NRCAM, CD44, TCF7) as coordinately upregulated in high-risk NBs without MYCN amplification in comparison to high-risk MYCN-amplified or intermediate-risk NBs, supporting pathway activation in this subset. Thus, high-risk NBs without MYCN amplification may deregulate MYC and other oncogenic genes via altered beta-catenin signaling providing a potential candidate pathway for therapeutic inhibition.

    Funded by: NCI NIH HHS: P01-CA97323

    Oncogene 2008;27;10;1478-88

  • Correlation between beta-catenin mutations and expression of Wnt-signaling target genes in hepatocellular carcinoma.

    Austinat M, Dunsch R, Wittekind C, Tannapfel A, Gebhardt R and Gaunitz F

    Institute for Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, 04103 Leipzig, Germany. Austinat_M@klinik.uni-wuerzburg.de

    Aberrant Wnt-signaling caused by mutants of beta-catenin, a key regulator of the canonical Wnt-signaling pathway, is frequently detected in cancer. Only recently, it was suggested that in hepatocellular carcinoma (HCC) the expression of the target gene glutamine synthetase (GS) is a highly reliable marker for the identification of beta-catenin mutations. In order to prove this hypothesis, 52 samples from human hepatocellular carcinomas were analysed for the activation of beta-catenin and the expression of GS. In total, 45 samples stained positive for cytoplasmic/nuclear beta-catenin. A strong correlation between expression of GS and activated beta-catenin (100% of nuclear and 84% of cytosolic) was found. However, among 35 GS positive tumors that were analysed for beta-catenin mutations no mutations were detected in 25 GS-positive carcinomas although 24 out of the 25 carcinomas exhibited at least abnormal expression of beta-catenin. Since the mutational analysis identified 9 different point mutations of the beta-catenin gene including the rare mutation H36P and the yet unknown mutation P44A it was asked whether these mutations may differently effect beta-catenin target genes. Therefore, expression plasmids for different mutations were constructed and cotransfected with the TOP-flash luciferase reporter and a reporter carrying the GS-5'-enhancer. The experiments confirmed that there are differences between different beta-catenin target sequences and different beta-catenin mutations. In addition, the failure that the endogenous expression of GS in GS-negative cells was not induced by the transient transfection experiment indicated that the effect of beta-catenin on the GS-5'-enhancer is only one aspect of gene activation induced by beta-catenin.

    Molecular cancer 2008;7;21

  • Compartmentalization in membrane rafts defines a pool of N-cadherin associated with catenins and not engaged in cell-cell junctions in melanoma cells.

    Rossier-Pansier L, Baruthio F, Rüegg C and Mariotti A

    Division of Experimental Oncology, Centre Pluridisciplinaire d'Oncologie, Lausanne Cancer Center and Swiss Institute for Experimental Cancer Research, CH-1066 Epalinges s/Lausanne, Switzerland.

    Melanoma progression is associated with changes in adhesion receptor expression, in particular upregulation of N-cadherin which promotes melanoma cell survival and invasion. Plasma membrane lipid rafts contribute to the compartmentalization of signaling complexes thereby regulating their function, but how they may affect the properties of adhesion molecules remains elusive. In this study, we addressed the question whether lipid rafts in melanoma cells may contribute to the compartmentalization of N-cadherin. We show that a fraction of N-cadherin in a complex with catenins is associated with cholesterol/sphingolipid-rich membrane microdomains in aggressive melanoma cells in vitro and experimental melanomas in vivo. Partitioning of N-cadherin in membrane rafts is not modulated by growth factors and signaling pathways relevant to melanoma progression, is not necessary for cell-cell junctions' establishment or maintenance, and is not affected by cell-cell junctions' and actin cytoskeleton disruption. These results reveal that two independent pools of N-cadherin exist on melanoma cell surface: one pool is independent of lipid rafts and is engaged in cell-cell junctions, while a second pool is localized in membrane rafts and does not participate in cell-cell adhesions. Targeting to membrane rafts may represent a previously unrecognized mechanism regulating N-cadherin function in melanoma cells.

    Journal of cellular biochemistry 2008;103;3;957-71

  • [Abnormalities of chromosome 8, APC and beta-catenin genes in aggressive fibromatosis].

    Yang JL, Wang J, Zhou XY and Zhu XZ

    Department of Pathology, Cancer Hospital, Fudan University, Shanghai 200032, China.

    Objective: To explore the role of abnormalities of chromosome 8, APC and beta-catenin genes in tumorigenesis of aggressive fibromatosis.

    Methods: Trisomy 8 was detected by interphase fluorescence in situ hybridization (FISH). The APC gene and beta-catenin gene mutations were detected by denaturing high performance liquid chromatography (DHPLC) and direct sequence analysis after the PCR transition.

    Results: The rate of trisomy 8 in recurrent tumors (62.5%, 5/8) was significantly higher than that in the primary tumors (8.3%, 1/12). Somatic substitution of APC gene was found in 18 of 69 (26.1%) aggressive fibrometases. Somatic transition of beta-catenin gene was detected in 13 of 69 (18.8%) and mutation at codon 41 in exon 3 involving threonine residues implicated in the degradation of beta-catenin. The abnormal expression of beta-catenin had no significant correlation with the mutation of APC or beta-catenin gene. The group with positively expressed beta-catenin protein showed a significant higher c-myc protein expression than those without (P = 0.001). The Ki-67 index was extremely low in all the lesions. The apoptosis index (AI) of the groups with positively expressed c-myc and cyclin D1 showed significantly lower AI than those without.

    Conclusion: Trisomy 8 may serve as a useful predictor of recurrence in aggressive fibromatosis. There are somatic mutations of the APC and beta-catenin genes in the aggressive fibromatosis, and there are abnormalities in the Wnt signaling pathway. These abnormalities may result in the aberrances of cell proliferation and apoptosis, which are likely to be import factors in the tumorigenesis.

    Zhonghua zhong liu za zhi [Chinese journal of oncology] 2008;30;2;116-20

  • [Effect of arsenic trioxide combined with bortezomib on proliferation, apoptosis and beta-catenin level in myeloma cell lines].

    Zhou LL, Fu WJ, Yuan ZG, Wang DX and Hou J

    Department of Hematology, Shanghai Changzheng Hospital, Shanghai 200003, China.

    The aim of this study was to investigate the effect of arsenic trioxide (As(2)O(3)) combined with bortezomib on the proliferation, apoptosis and beta-catenin level in myeloma cell lines. Myeloma cell lines RPMI8226, CZ-1 and NCI-H929 were treated with As(2)O(3) and bortezomib alone or in combination for 48 hours. Trypan blue dye exclusion and modified MTT were used to assess the cell viability. Flow cytometry with Annexin V-FITC and PI staining was used to detect the apoptosis rate. The beta-catenin level was analyzed by Western blot. The results showed that IC(50) of bortezomib to RPMI8226, CZ-1 and NCI-H929 were 46.9, 20.7 and 6.8 nmol/L, respectively. After the combination treatment with bortezomib (5 nmol/L) and As(2)O(3) (1 micromol/L), the cell viability of RPMI8226, CZ-1 and NCI-H929 decreased from 88.99%, 72.23%, 51.06% to 54.01%, 39.59%, 25.00%(p<0.05), the apoptosis rate increased from 11.1+/-0.1%, 26.8+/-1.7%, 46.8+/-5.5% to 36.1+/-2.2%, 60.4+/-3.8%, 76+/-5.6% (p<0.01) respectively. The Q value of two groups lies between enhancement and significant enhancement (1.198 - 3.75). Besides, beta-catenin levels in tested cell lines were decreased to 24.15%, 31.85%, 33.72% of their basic constitutions respectively (p<0.05). It is concluded that combination treatment of As(2)O(3) and bortezomib can enhance the proliferation inhibition and apoptosis induction of bortezomib to myeloma cell lines, reduce beta-catenin level, and increase the sensitivity of myeloma cell lines to bortezomib.

    Zhongguo shi yan xue ye xue za zhi 2008;16;1;84-8

  • Establishment of immortalized multipotent hematopoietic progenitor cell lines by retroviral-mediated gene transfer of beta-catenin.

    Templin C, Kotlarz D, Rathinam C, Rudolph C, Schätzlein S, Ramireddy K, Rudolph KL, Schlegelberger B, Klein C and Drexler H

    Department of Cardiology and Angiology, Hannover Medical School, Hannover, Germany. templin.christian@mh-hannover.de

    Objective: Hematopoietic stem cells (HSCs) are characterized by their ability to give rise to all mature blood lineages and to renew themselves. In the present study, we show that beta-catenin plays an essential role in the immortalization of hematopoietic progenitor cells (HPCs).

    Cellular, molecular, and cytogenetic properties of the immortalized HPCs were determined using flow cytometry (immunophenotyping), microscopy (telomere length, spectral karyotyping), telomere repeat amplification protocol assay (telomerase activity), real-time polymerase chain reaction (expression studies), and in vitro and in vivo differentiation assays.

    Results: Retroviral-mediated overexpression of human beta-catenin in lin(-)- and lin(-)Sca-1+c-kit+ hematopoietic cells led to generation of novel, murine interleukin-3-, and stem cell factor-dependent hematopoietic multipotent progenitor cell lines (DK1mix and DK2mix) with stable surface antigen expression of the stem cell markers Sca-1 and c-kit (>92%) in long-term culture. Further, immunophenotypic characterization revealed a CD244+CD150(-)CD48(-) phenotype of DKmix cells, which is consistent with the expression profile of multipotential hematopoietic progenitors. Upon exposure to selective hematopoietic cytokines in vitro, and upon transplantation into irradiated congenic recipients, DKmix cells generated progenies of lymphoid and myeloid lineages. Continuous in vitro proliferation and expansion of DKmix cells were associated with stabilized telomere length and consistent telomerase activity. Interestingly, constitutive expression of beta-catenin was not required for sustained long-term viability and proliferation of immortalized DKmix cells.

    Conclusion: In summary, our findings define beta-catenin as an important regulator in HPC self-renewal and function. Further, our results distinguish the importance of beta-catenin in the immortalization process of HPCs, from its dispensable role in their maintenance.

    Experimental hematology 2008;36;2;204-15

  • TBL1-TBLR1 and beta-catenin recruit each other to Wnt target-gene promoter for transcription activation and oncogenesis.

    Li J and Wang CY

    Laboratory of Molecular Signalling, Division of Oral Biology and Medicine, UCLA School of Dentistry, Los Angeles, CA 90095, USA.

    Aberrant Wnt signalling promotes oncogenesis by increasing the nuclear accumulation of beta-catenin to activate downstream target genes. However, the mechanism of beta-catenin recruitment to the Wnt target-gene promoter, a critical step for removing the co-repressor complex, is largely unknown. Here, we report that transducin beta-like protein 1 (TBL1) and its highly related family member TBLR1 were required for Wnt-beta-catenin-mediated transcription. Wnt signalling induced the interaction between beta-catenin and TBL1-TBLR1, as well as their binding to Wnt target genes. Importantly, the recruitment of TBL1-TBLR1 and beta-catenin to Wnt target-gene promoters was mutually dependent on each other. Furthermore, the depletion of TBL1-TBLR1 significantly inhibited Wnt-beta-catenin-induced gene expression and oncogenic growth in vitro and in vivo. Our results unravel two new components required for nuclear beta-catenin function, and have important implications in developing new strategies for inhibiting Wnt-beta-catenin-mediated tumorigenesis.

    Nature cell biology 2008;10;2;160-9

  • Wnt/beta-catenin inhibits dental pulp stem cell differentiation.

    Scheller EL, Chang J and Wang CY

    Laboratory of Molecular Signaling, Department of Biologic and Materials Sciences, School of Dentistry, The University of Michigan, Ann Arbor, MI 48109, USA.

    Dental pulp stem cells (DPSCs) are a unique precursor population isolated from postnatal human dental pulp and have the ability to regenerate a reparative dentin-like complex. Canonical Wnt signaling plays a critical role in tooth development and stem cell self-renewal through beta-catenin. In this study, the regulation of odontoblast-like differentiation of DPSCs by canonical Wnt signaling was examined. DPSCs were stably transduced with canonical Wnt-1 or the active form of beta-catenin, with retrovirus-mediated infection. Northern blot analysis found that Wnt-1 strongly induced the expression of matricellular protein osteopontin, and modestly enhanced the expression of type I collagen in DPSCs. Unexpectedly, Wnt-1 inhibited alkaline phosphatase (ALP) activity and the formation of mineralized nodules in DPSCs. Moreover, over-expression of beta-catenin was also sufficient to suppress the differentiation and mineralization of DPSCs. In conclusion, our results suggest that canonical Wnt signaling negatively regulates the odontoblast-like differentiation of DPSCs.

    Funded by: NIDCR NIH HHS: F30 DE019577, F30 DE019577-01, R01 DE016513, R01DE 016513, T32 DE007057, T32DE 007057

    Journal of dental research 2008;87;2;126-30

  • Ajuba negatively regulates the Wnt signaling pathway by promoting GSK-3beta-mediated phosphorylation of beta-catenin.

    Haraguchi K, Ohsugi M, Abe Y, Semba K, Akiyama T and Yamamoto T

    Division of Oncology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.

    The Wnt signaling pathway is essential for embryonic development and carcinogenesis. Upon Wnt stimulation, beta-catenin is stabilized and associates with T-cell factor or lymphoid enhancing factor, thereby activating transcription of target genes. In the absence of Wnt stimulation, the level of beta-catenin is reduced via glycogen synthase kinase (GSK)-3beta-mediated phosphorylation and subsequent proteasome-dependent degradation. Here, we report the identification of Ajuba as a negative regulator of the Wnt signaling pathway. Ajuba is a member of LIM domain-containing proteins that contribute to cell fate determination and regulate cell proliferation and differentiation. We found that enforced expression of Ajuba destabilized beta-catenin and suppressed target gene expression. Ajuba promoted GSK-3beta-mediated phosphorylation of beta-catenin by reinforcing the association between beta-catenin and GSK-3beta. Furthermore, Wnt stimulation induced both accumulation of beta-catenin and destabilization of Ajuba. Our findings suggest that Ajuba is important for regulation of the Wnt signaling pathway.

    Oncogene 2008;27;3;274-84

  • beta-Catenin is a Nek2 substrate involved in centrosome separation.

    Bahmanyar S, Kaplan DD, Deluca JG, Giddings TH, O'Toole ET, Winey M, Salmon ED, Casey PJ, Nelson WJ and Barth AI

    Department of Biological Sciences, Stanford University, Stanford, California 94305, USA.

    beta-Catenin plays important roles in cell adhesion and gene transcription, and has been shown recently to be essential for the establishment of a bipolar mitotic spindle. Here we show that beta-catenin is a component of interphase centrosomes and that stabilization of beta-catenin, mimicking mutations found in cancers, induces centrosome splitting. Centrosomes are held together by a dynamic linker regulated by Nek2 kinase and its substrates C-Nap1 (centrosomal Nek2-associated protein 1) and Rootletin. We show that beta-catenin binds to and is phosphorylated by Nek2, and is in a complex with Rootletin. In interphase, beta-catenin colocalizes with Rootletin between C-Nap1 puncta at the proximal end of centrioles, and this localization is dependent on C-Nap1 and Rootletin. In mitosis, when Nek2 activity increases, beta-catenin localizes to centrosomes at spindle poles independent of Rootletin. Increased Nek2 activity disrupts the interaction of Rootletin with centrosomes and results in binding of beta-catenin to Rootletin-independent sites on centrosomes, an event that is required for centrosome separation. These results identify beta-catenin as a component of the intercentrosomal linker and define a new function for beta-catenin as a key regulator of mitotic centrosome separation.

    Funded by: NCI NIH HHS: CA100869, R01 CA100869; NIGMS NIH HHS: GM074746, GM078270, R01 GM074746, R01 GM078270, T32 GM007276, T32GM07276-27

    Genes & development 2008;22;1;91-105

  • Overexpression of E-cadherin and beta-catenin proteins in metastatic prostate cancer cells in bone.

    Saha B, Arase A, Imam SS, Tsao-Wei D, Naritoku WY, Groshen S, Jones LW and Imam SA

    Gene Therapy Program, Huntington Medical Research Institutes, Pasadena, California 91101, USA.

    Background: The expression of E-cadherin in the intercellular adhesion of metastatic prostate cancer cells in bone, which is the most prevalent site of metastatic growth, remains elusive.

    Methods: The aim of the study was to compare the concurrent membranous expression of E-cadherin and beta-catenin proteins, the state which is known to be associated with the cellular adhesion function of E-cadherin, in prostate biopsy tissue specimens by immunohistochemical staining method. The expression patterns of E-cadherin or beta-catenin were classified as homogeneous (most cells exhibiting positively), heterogeneous (a few scattered patches of cells with positivity) or negative.

    Results: Benign prostate hyperplasia cells exhibited homogeneous expression of both E-cadherin and beta-catenin in 9 of 11 (82%), whereas the primary prostate cancer cells were homogeneously positive for both proteins only in 4 of 22 (18%) of the cases. The results are similar to those reported in literature. However, in contrast to the primary cancer, a significantly increased frequency of the metastatic prostate cancer cells in bone exhibited homogeneous expression of E-cadherin and beta-catenin in 12 of 17 (71%) of the cases. A statistically significant association was observed between the overexpression of both proteins and the metastatic prostate cancer cells in bone (Fisher's exact P < 0.001).

    Conclusions: The result of the study demonstrated for the first time that the membranous overexpression of E-cadherin and beta-catenin are significantly associated with the metastatic prostate cancer cells in bone and that the high frequency of expression suggest their involvement in the intercellular adhesion of the metastatic cells in bone.

    The Prostate 2008;68;1;78-84

  • Desmoid tumor: a disease opportune for molecular insights.

    Kotiligam D, Lazar AJ, Pollock RE and Lev D

    Department of Cancer Biology and Sarcoma Research Centre, UT-MD Anderson Cancer Center, Houston, Texas, USA.

    Desmoid tumors are monoclonal proliferations that fall within a broad histologic spectrum of fibrous mesenchymal tumors that ranges from benign proliferations of scar tissue to high-grade fibrosarcomas. These low-grade tumors are extremely infiltrative locally, but lack the ability to metastasize systemically. While they are only rarely a direct cause of mortality, using current therapeutic modalities, these tumors have a high rate of local recurrence that can result in significant treatment related morbidity. Sporadic desmoids are usually associated with somatic mutations in codons 41 or 45 of exon 3 of beta-catenin (CTNNB1). Desmoid tumors occurring in the background of familial adenomatous polyposis (FAP) usually contain inactivating germline mutations in the adenomatous polyposis coli (APC) gene. CTNNB1 and APC are part of the Wnt signaling pathway and mutations in either gene result in stabilization of the beta-catenin protein and allow nuclear translocation and binding of beta-catenin to the T-cell factor/lymphoid enhancer factor (TCF/Lef) family of transcription factors, resulting in activation of target genes which may underlie desmoid tumor biology and clinical behavior. In an era of molecularly targeted therapeutics there is a real need to better grasp the molecular mechanisms behind desmoid tumorigenesis and progression. This knowledge will eventually result in the development of patient and tumor tailored therapies and assist in the control and eradication of this disease.

    Histology and histopathology 2008;23;1;117-26

  • Downregulation of Dkk3 activates beta-catenin/TCF-4 signaling in lung cancer.

    Yue W, Sun Q, Dacic S, Landreneau RJ, Siegfried JM, Yu J and Zhang L

    Department of Pharmacology.

    Although the oncogenic role of the Wnt/beta-catenin pathway is well defined, it remains unclear how this pathway is aberrantly activated in lung cancer. We found that Dickkopf (Dkk)-3, a member of Dkk family of Wnt antagonists, is frequently inactivated in lung cancer and plays a role in suppressing lung cancer cell growth through inhibition of beta-catenin/T-cell factor (TCF)-4 signaling. Dkk3 is the only Dkk family member abundantly expressed in normal lung, but silenced by promoter hypermethylation in a large fraction of lung cancer cell lines and lung tumors. Downregulation of Dkk3 was correlated with tumor progression and expression of nuclear beta-catenin in lung tumors. Ectopic expression of Dkk3 in lung cancer cells with Dkk3 hypermethylation induced apoptosis and inhibited TCF-4 activity as well as nuclear accumulation of beta-catenin and expression of TCF-4 targets c-Myc and cyclin D1. Furthermore, small interference RNA knock down of Dkk3 in cells lacking Dkk3 hypermethylation was sufficient to promote cell proliferation, beta-catenin nuclear translocation and expression of c-Myc. These observations suggested that epigenetic inactivation of Dkk3 activates the Wnt/beta-catenin pathway, thereby promoting the growth of lung cancer cells.

    Funded by: NCI NIH HHS: CA106348, CA121105, CA90440, P50 CA090440, R01 CA106348

    Carcinogenesis 2008;29;1;84-92

  • Sporadic childhood hepatoblastomas show activation of beta-catenin, mismatch repair defects and p53 mutations.

    Curia MC, Zuckermann M, De Lellis L, Catalano T, Lattanzio R, Aceto G, Veschi S, Cama A, Otte JB, Piantelli M, Mariani-Costantini R, Cetta F and Battista P

    Department of Oncology, University of Chieti-Pescara, Chieti, Italy. mc.curia@unich.it

    Hepatoblastoma, a rare embryonic tumor that may arise sporadically or in the context of hereditary syndromes (familial adenomatous polyposis and Beckwith-Wiedemann's) is the most frequent liver cancer of childhood. Deregulation of the APC/beta-catenin pathway occurs in a consistent fraction of hepatoblastomas, with mutations in the APC and beta-catenin genes implicated in familial adenomatous polyposis-associated and sporadic hepatoblastomas, respectively. Alterations in other cancer-related molecular pathways have not been reported. We investigated a series of 21 sporadic paraffin-embedded hepatoblastoma cases for mutations in the p53 (exons 5-8) and beta-catenin (exon 3) genes, loss of heterozygosity at APC, microsatellite instability and immunohistochemical expression of beta-catenin and of the two main mismatch repair proteins, MLH1 and MSH2. No loss of heterozygosity at APC was detected. We found mutations in beta-catenin and p53 in 4/21 (19%) and 5/21 (24%) cases respectively, beta-catenin protein accumulation in 14/21 cases (67%), microsatellite instability in 17/21 cases (81%), of which eight resulted positive for high-level of microsatellite instability (in four cases associated with loss of MLH1/MSH2 immunostaining). No correlations between involved molecular pathway(s) and hepatoblastoma histotype(s) emerged. This study confirms that beta-catenin deregulation is involved in sporadic hepatoblastoma and also suggests that mismatch repair defects and p53 mutations contribute to this rare liver cancer. Sporadic hepatoblastoma appears to be molecularly and phenotypically heterogeneous and may reflect different pathways of liver carcinogenesis.

    Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2008;21;1;7-14

  • The PDZ protein erbin modulates beta-catenin-dependent transcription.

    Ress A and Moelling K

    Institute of Medical Virology, University of Zurich, Zurich, Switzerland. angelika.ress@gmx.net

    Erbin is a member of the leucine-rich repeat and PDZ domain family that can regulate proliferation, differentiation and cell adhesion. As a binding partner of the receptor tyrosine kinase ErbB2, erbin targets this receptor to the basolateral membrane of polarized epithelial cells. In addition, erbin is known to inhibit the Ras-mediated activation of the mitogen-activated protein kinase pathway. Recently we identified the proto-oncoprotein beta-catenin as a ligand of the PDZ domain of erbin. Here we demonstrate that erbin acts as a negative regulator of the beta-catenin/T-cell-factor-dependent gene expression. In contrast, a mutant of erbin with a deletion of the N-terminal leucine-rich repeat allows the PDZ domain of erbin to increase the beta-catenin/T-cell-factor-dependent transcription. This mutant localizes to the nucleus and mimics a putative splice variant found in keratinocytes. Thus, erbin has the potential to act as an inhibitor as well as an activator of the beta-catenin-regulated gene expression.

    European surgical research. Europaische chirurgische Forschung. Recherches chirurgicales europeennes 2008;41;3;284-9

  • Effects of hepatitis B virus X protein (HBx) on cell-growth inhibition in a CCL13-HBx stable cell line.

    Kuo CY, Wang JC, Wu CC, Hsu SL and Hwang GY

    Department of Life Science, Tunghai University, Taichung, Taiwan.

    Objective: The known function of hepatitis B virus X protein (HBx) is to determine the fate of cells by modulating various signaling pathways. In our previous study, we demonstrated that HBx inhibits tumor formation in nude mice injected with CCL13-HBx stable cell lines; however, the mechanism underlying this inhibition is unclear.

    Methods: To investigate the possible mechanisms underlying HBx involvement in CCL13-HBx cells, gene profiles were initially analyzed by DNA microarray technology and subsequently confirmed by performing semiquantitative RT-PCR and Western blotting. Furthermore, the phenomenon of cell death via apoptosis was detected via DNA fragmentation, TUNEL staining, caspase-3 activity assay, and propidium iodide (PI) staining.

    Results: The results indicated that HBx induction downregulated Wnt-3 and beta-catenin that are involved in cell proliferation. Moreover, HBx induction repressed cell growth and downregulated the expressions of cyclin D1, CDK4, cyclin E, CDK2, and cyclin B1. Furthermore, HBx induction triggered cell death via apoptosis, as determined by DNA fragmentation, TUNEL staining, caspase-3 activity assay, and PI staining.

    Conclusion: Most importantly, our results indicated that HBx induction in the CCL13-HBx stable cell line downregulated Wnt-3/beta-catenin expression and suppressed cell growth by repressing cell proliferation or triggering cell apoptosis.

    Intervirology 2008;51;1;26-32

  • Frequent epigenetic inactivation of SFRP genes in hepatocellular carcinoma.

    Takagi H, Sasaki S, Suzuki H, Toyota M, Maruyama R, Nojima M, Yamamoto H, Omata M, Tokino T, Imai K and Shinomura Y

    First Department of Internal Medicine, Sapporo Medical University, S1, W16, Chuo-Ku, Sapporo 060-8543, Japan.

    Background: Activation of the Wnt signaling pathway is frequently observed in hepatocellular carcinoma (HCC), though mutation of three of its components, CTNNB1, AXIN1, and AXIN2, is observed substantially less often.

    Methods: We examined the relationship between Wnt signaling and epigenetic alteration of secreted frizzled-related protein (SFRP) genes in HCC.

    Results: We frequently detected the active form of beta-catenin and accumulation of nuclear beta-catenin in liver cancer cell lines. We detected methylation of SFRP family genes in liver cancer cell lines (SFRP1, 9/12, 75%; SFRP2, 7/12, 58%; SFRP4, 3/12, 25%; SFRP5, 7/12, 58%) and primary HCCs (SFRP1, 9/19, 47%; SFRP2, 12/19, 63%; SFRP5, 8/19, 42%), though methylation of SFRP4 was not found in primary HCCs. SFRP methylation also was detected in hepatitis B or C virus-associated chronic hepatitis (SFRP1, 6/37, 16%; SFRP2, 14/37, 38%; SFRP5, 5/37, 14%) and liver cirrhosis (SFRP1, 10/28, 36%; SFRP2, 9/28, 32%; SFRP5, 3/28, 11%), suggesting that methylation of these genes is an early event in liver carcinogenesis. Ectopic expression of SFRPs downregulated T-cell factor/lymphocyte enhancer factor (TCF/LEF) transcriptional activity in liver cancer cells, while overexpression of a beta-catenin mutant and depletion of SFRP1 using siRNA synergistically upregulated TCF/LEF transcriptional activity.

    Conclusions: Our results confirm the frequent methylation and silencing of Wnt antagonist genes in HCC, and suggest that their loss of function contributes to activation of Wnt signaling during hepatocarcinogenesis.

    Journal of gastroenterology 2008;43;5;378-89

  • HBx inhibits the growth of CCL13-HBX-stable cells via the GSK-3beta/beta-catenin cascade.

    Kuo CY, Wu CC, Hsu SL and Hwang GY

    Department of Life Science, Tunghai University, Taichung, Taiwan.

    Objective: The hepatitis B virus X protein (HBx) plays critical roles in cell survival via modulation of signaling pathways. In our previous studies, we reported that HBx inhibited the growth of CCL13-HBx-stable cells (Chang-HBx cells) in vitro and tumor formation in vivo in CCL13-HBx-cell-injected nude mice; however, this inhibition mechanism is unclear.

    Methods: To investigate the role of HBx in Wnt-3/beta-catenin signaling pathways, we focused on the key molecules GSK-3beta and beta-catenin, and analyzed by Western blotting and immunofluorescence staining.

    Results: Results indicated that following HBx induction, GSK-3beta activity was up-regulated, the expression and accumulation of beta-catenin in the nucleus were decreased, and cell proliferation was suppressed. Inhibition of GSK-3beta activity by pharmacological inhibitors rescued the expression and accumulation of beta-catenin in the nucleus and facilitated cell proliferation and growth following HBx induction. The localization of beta-catenin, which is involved in cell proliferation, and mediated by GSK-3beta activation was also demonstrated.

    Conclusion: Our findings suggest that HBx negatively regulated proliferation of CCL13-HBx-stable cells via the GSK-3beta/beta-catenin cascade.

    Intervirology 2008;51;2;130-6

  • Immunoexpression of beta-catenin--E-cadherin complex in primary serous ovarian tumors.

    Stawerski P, Wagrowska-Danilewicz M, Stasikowska O, Gottwald L and Danilewicz M

    Department of Nephropathology, Medical University of Lódź. paulost@plusnet.pl

    Ovarian cancer takes a fourth place as cause of death from all cancers and a first place from gynecologic malignancies in Poland. Up to now, relatively little is known about immunohistochemical markers accepted as prognostic indicators for ovarian cancers. Recent investigations took a note of prognostic significance of catenin-cadherin adhesion complex and Ki-67 proliferation protein in serous ovarian cancers. The aim of the study was to evaluate the immunoexpression of beta-catenin and E-cadherin in metastatic and nonmetastatic serous ovarian tumors, as well as to find possible relationships between this immunoexpression and tumor proliferation activity. The analysis comprised of 66 women diagnosed and treated for epithelial ovarian tumors. On immunohistochemical examinations it was found a significantly lower immunoexpression of beta-catenin and E-cadherin in invasive serous ovarian cancers than in cystadenomas. Additionally, in metastatic group the immunoexpression of both beta-catenin and E-cadherin was significantly decreased as compared with patients without metastases. Moreover, the significant inverse correlations have been shown between immunoexpression of Ki-67 and beta-catenin as well as Ki-67 and E-cadherin. In conclusion, our data suggest that decreased immunoexpression of beta-catenin and E-cadherin in serous ovarian tumors may be helpful in identifying the cases of higher metastatic potential and infiltration ability.

    Polish journal of pathology : official journal of the Polish Society of Pathologists 2008;59;1;27-32

  • P-cadherin and beta-catenin are useful prognostic markers in breast cancer patients; beta-catenin interacts with heat shock protein Hsp27.

    Fanelli MA, Montt-Guevara M, Diblasi AM, Gago FE, Tello O, Cuello-Carrión FD, Callegari E, Bausero MA and Ciocca DR

    Oncology Laboratory, Institute of Experimental Medicine and Biology of Cuyo, Regional Center for Scientific and Technological Research, National Research Council (CONICET), Mendoza, Argentina. mfanelli@lab.cricyt.edu.ar

    The cadherin-catenin proteins have in common with heat shock proteins (HSP) the capacity to bind/interact proteins of other classes. Moreover, there are common molecular pathways that connect the HSP response and the cadherin-catenin protein system. In the present study, we have explored whether in breast cancer the HSP might interact functionally with the cadherin-catenin cell adhesion system. Beta-catenin was immunoprecipitated from breast cancer biopsy samples, and the protein complexes isolated in this way were probed with antibodies against HSP family members. We are thus the first to demonstrate a specific interaction between beta-catenin and Hsp27. However, beta-catenin did not bind Hsp60, Hsp70, Hsp90, gp96, or the endoplasmic reticulum stress response protein CHOP. To confirm the finding of Hsp27-beta-catenin interaction, the 27-kDa immunoprecipitated band was excised from one-dimensional polyacrylamide gel electrophoresis gels and submitted to liquid chromatography-tandem mass spectrometry with electrospray ionization, confirming a role for Hsp27. In addition, beta-catenin interacted with other proteins including heat shock transcription factor 1, P-cadherin, and caveolin-1. In human breast cancer biopsy samples, beta-catenin was coexpressed in the same tumor areas and in the same tumor cells that expressed Hsp27. However, this coexpression was strong when beta-catenin was present in the cytoplasm of the tumor cells and not when beta-catenin was expressed at the cell surface only. Furthermore, murine breast cancer cells transfected with hsp25 showed a redistribution of beta-catenin from the cell membrane to the cytoplasm. When the prognostic significance of cadherin-catenin expression was examined by immunohistochemistry in breast cancer patients (n = 215, follow-up = >10 years), we found that the disease-free survival and overall survival were significantly shorter for patients expressing P-cadherin and for patients showing expression of beta-catenin in the cytoplasm only (not at the cell surface). The interactions of beta-catenin with Hsp27 and with HSF1 may explain some of the molecular pathways that influence tumor cell survival and the clinical significance in the prognosis of the breast cancer patients.

    Cell stress & chaperones 2008;13;2;207-20

  • ShRNA-mediated gene silencing of beta-catenin inhibits growth of human colon cancer cells.

    Huang WS, Wang JP, Wang T, Fang JY, Lan P and Ma JP

    Surgery Department, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.

    Aim: To observe the gene silencing mediated by the specific shRNA targeted against beta-catenin and its effect on cell proliferation and cycle distribution in the human colon cancer cell line Colo205.

    Methods: Two shRNA plasmid vectors against beta-catenin were constructed and transfected into Colo205 cells with Lipofectamine2000. The down-regulations of beta-catenin, c-myc and cyclinD1 expressions were detected by RT-PCR and western blot analysis. The cell proliferation inhibitions were determined by MTT assay and soft agar colony formation assay. The effect of these two beta-catenin shRNAs on cell cycle distribution and apoptosis was examined by flow cytometry.

    Results: These two shRNA vectors targeted against beta-catenin efficiently suppressed the expression of beta-catenin and its down stream genes, c-myc and cyclinD1. The expression inhibition rates were around 40%-50% either at the mRNA or at the protein level. The shRNA-mediated gene silencing of beta-catenin resulted in significant inhibition of cell growth both on the culture plates and in the soft agar. Moreover, the cancer cells showed significant G0/G1 arrest and increased apoptosis at 72 h post transfection due to gene silencing.

    Conclusion: These specific shRNAs targeted against beta-catenin could have a gene silencing effect and block the WNT signaling pathway. They could inhibit cell growth, increase apoptosis, and induce cell cycle arrest in Colo205 cells. ShRNA interference against beta-catenin is of potential value in gene therapy of colon cancer.

    World journal of gastroenterology : WJG 2007;13;48;6581-7

  • The tumor suppressor Fhit acts as a repressor of beta-catenin transcriptional activity.

    Weiske J, Albring KF and Huber O

    Department of Laboratory Medicine and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany.

    The Fra3B locus on chromosome 3p14.2 targeting the fragile histidine triad (Fhit) gene represents one of the most common fragile sites of the human genome and is associated with early preneoplastic and malignant disorders in multiple human tumors. Fhit was classified as a tumor suppressor; however, the molecular mechanisms of its function are not well established. Here, we report that Fhit associates with the lymphoid enhancer-binding factor 1/T cell factor/beta-catenin complex by directly binding to beta-catenin, a major player in the canonical Wnt pathway that is deregulated in numerous forms of human cancer. In binding to the beta-catenin C-terminal domain, Fhit represses transcription of target genes such as cyclin D1, axin2, MMP-14, and survivin. Knockdown of Fhit reversed this effect, whereas this reversal was not detectable when beta-catenin was knocked down simultaneously. The Fhit enzymatic activity as a diadenosine-polyphosphate hydrolase is not required for the down-regulation of beta-catenin-mediated transcription as examined with an enzymatic inactive Fhit-H96N protein. ChIPs revealed recruitment of Fhit/beta-catenin complexes to target gene promoters. In soft agar assays Fhit and beta-catenin are involved in regulation of anchorage-independent growth. These observations assign to the tumor suppressor Fhit an unexpected role in the regulation of beta-catenin-mediated gene transcription.

    Proceedings of the National Academy of Sciences of the United States of America 2007;104;51;20344-9

  • A novel role of Rac1 GTPase in JCV T-antigen-mediated beta-catenin stabilization.

    Bhattacharyya R, Noch EK and Khalili K

    Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, PA 19122, USA.

    Wnt signaling follows canonical and non-canonical pathways to regulate a variety of processes during cellular homeostasis and development. The large T-antigen (T-Ag) of the human neurotropic JC virus, has been shown to modulate the Wnt-signaling pathway via interaction with beta-catenin, one of the most important components of the canonical Wnt pathway. Here, we have identified an alternative non-canonical pathway that allows T-Ag to recruit Rac1 for stabilizing beta-catenin by inhibiting its ubiquitin-dependent proteasomal degradation. We demonstrate that inhibition of Rac1 by its dominant negative mutant, RacN17, abrogates T-Ag-mediated stabilization of beta-catenin yet exhibits no impact on the transcriptional activity of beta-catenin. Results from immunocytochemistry revealed that together with T-Ag, a pool of beta-catenin appears at the cell surface, particularly at the membrane ruffles where active Rac1 is positioned. Interestingly, cooperativity between T-Ag and beta-catenin leads to activation of Rac1, which in turn, stimulates its association with beta-catenin. These observations unravel the interplay between beta-catenin and Rac1 that is initiated by T-Ag and results in stabilization of beta-catenin and its presence in cell membrane ruffles.

    Oncogene 2007;26;55;7628-36

  • Confluence induced threonine41/serine45 phospho-beta-catenin dephosphorylation via ceramide-mediated activation of PP1cgamma.

    Marchesini N, Jones JA and Hannun YA

    Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 175 Ashley Ave., POB 250509, Charleston, SC 29425, USA.

    It was previously observed that cell confluence induced up-regulation of neutral sphingomyelinase 2 (nSMase2) and increased ceramide levels [Marchesini N., Osta W., Bielawski J., Luberto C., Obeid L.M. and Hannun Y.A. (2004) J. Biol. Chem., 279, 25101-11]. In this study, we show that, in MCF7 cells, confluence induces the dephosphorylation of phosphorylated-beta-catenin at threonine41/serine45. The effect of confluence on beta-catenin dephosphorylation was prevented by down regulation of nSMase2 using siRNA; reciprocally, exogenous addition of short or very long chain ceramides induced dephosphorylation of beta-catenin. The serine/threonine protein phosphatase inhibitors calyculin A and okadaic acid prevented beta-catenin dephosphorylation during confluence. The specific phosphatase involved was determined by studies using siRNA against the major serine/threonine phosphatases, and the results showed that a specific siRNA against PP1cgamma prevented dephosphorylation of beta-catenin. Moreover, exogenous ceramides and confluence were found to induce the translocation of PP1cgamma to the plasma membrane. All together these results establish: A) a specific intracellular pathway involving the activation of PP1 to mediate the effects of confluence-induced beta-catenin dephosphorylation and B) PP1 as a lipid-regulated protein phosphatase downstream of nSMase2/ceramide. Finally, evidence is provided for a role for this pathway in regulating cell motility during confluence.

    Funded by: NCI NIH HHS: CA87584, R01 CA087584; NIGMS NIH HHS: GM 43825, R01 GM043825, R37 GM043825, R37 GM043825-18

    Biochimica et biophysica acta 2007;1771;12;1418-28

  • Expression of Wnt5a and its downstream effector beta-catenin in uveal melanoma.

    Zuidervaart W, Pavey S, van Nieuwpoort FA, Packer L, Out C, Maat W, Jager MJ, Gruis NA and Hayward NK

    Department of Ophthalmology, Skin Research Lab, Leiden University Medical Centre, Leiden, The Netherlands. w.zuidervaart@lumc.nl

    Upregulation of the Wnt5a pathway has been reported in some cutaneous melanomas but its role in uveal melanoma has not been assessed. We thus sought to determine whether activation of the Wnt-signalling pathway occurred in uveal melanoma through upregulation of some of the key downstream effectors, and whether expression of these components was associated with tumour characteristics and clinical outcome. Expression of Wnt5a, MMP7, and beta-catenin was determined in 40 primary uveal melanomas by immunohistochemistry and correlated with patient prognosis. The proportion of cells immunoreactive for Wnt5a, MMP7, and beta-catenin was higher in tumours from patients with shorter survival and this difference was statistically significant for Wnt5a (P<0.01) and beta-catenin (P=0.02). These data show for the first time activation of the Wnt/beta-catenin-signalling pathway in uveal melanoma and suggest that components of this pathway might be useful prognostic markers as well as attractive therapeutic targets to treat this disease.

    Melanoma research 2007;17;6;380-6

  • FLT3 regulates beta-catenin tyrosine phosphorylation, nuclear localization, and transcriptional activity in acute myeloid leukemia cells.

    Kajiguchi T, Chung EJ, Lee S, Stine A, Kiyoi H, Naoe T, Levis MJ, Neckers L and Trepel JB

    Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. tomokaji@med.nagoya-u.ac.jp

    Deregulated accumulation of nuclear beta-catenin enhances transcription of beta-catenin target genes and promotes malignant transformation. Recently, acute myeloid leukemia (AML) cells with activating mutations of FMS-like tyrosine kinase-3 (FLT3) were reported to display elevated beta-catenin-dependent nuclear signaling. Tyrosine phosphorylation of beta-catenin has been shown to promote its nuclear localization. Here, we examined the causal relationship between FLT3 activity and beta-catenin nuclear localization. Compared to cells with wild-type FLT3 (FLT3-WT), cells with the FLT3 internal tandem duplication (FLT3-ITD) and tyrosine kinase domain mutation (FLT3-TKD) had elevated levels of tyrosine-phosphorylated beta-catenin. Although beta-catenin was localized mainly in the cytoplasm in FLT3-WT cells, it was primarily nuclear in FLT3-ITD cells. Treatment with FLT3 kinase inhibitors or FLT3 silencing with RNAi decreased beta-catenin tyrosine phosphorylation and nuclear localization. Conversely, treatment of FLT3-WT cells with FLT3 ligand increased tyrosine phosphorylation and nuclear accumulation of beta-catenin. Endogenous beta-catenin co-immunoprecipitated with endogenous activated FLT3, and recombinant activated FLT3 directly phosphorylated recombinant beta-catenin. Finally, FLT3 inhibitor decreased tyrosine phosphorylation of beta-catenin in leukemia cells obtained from FLT3-ITD-positive AML patients. These data demonstrate that FLT3 activation induces beta-catenin tyrosine phosphorylation and nuclear localization, and thus suggest a mechanism for the association of FLT3 activation and beta-catenin oncogeneic signaling in AML.

    Leukemia 2007;21;12;2476-84

  • Green tea polyphenol and epigallocatechin gallate induce apoptosis and inhibit invasion in human breast cancer cells.

    Thangapazham RL, Passi N and Maheshwari RK

    Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.

    Currently, there is no effective therapy for estrogen independent breast cancer. MDA-MB-231 is an estrogen receptor negative highly invasive human breast cancer cell line and has been used as a relevant model system to evaluate drugs with chemopreventive potential against highly invasive breast cancer phenotypes. Epidemiological studies though inconclusive have shown that consumption of Green Tea Polyphenols (GTP) reduces the incidence and progression of breast cancer. Green tea is an important source of antioxidants that may be useful for chemoprevention of cancer. Recently published preclinical study from our lab suggested that GTP and EGCG treatment inhibit proliferation and induce apoptosis of MDA-MB-231. In this study, we have evaluated apoptotic and anti-invasive activity of green tea polyphenols (GTP) and its principal constituent Epigallocatechin gallate (EGCG) in MDA-MB-231 human breast cancer cell line. In in vitro human breast cancer model, EGCG and GTP induced apoptosis and significantly decreased invasion of breast cancer cells. Western blotting of MDA-MB-231 cell lysates from EGCG and GTP treated and untreated control revealed an increase in bax, reduction in bcl2 and PARP cleavage. Quantitative fluorescence labeling resulted in a 24-28% reduction in invasion through matrigel by EGCG and 15-23% reduction by GTP in a dose dependent manner. Focussed microarray analysis and reverse transcriptase polymerase chain reaction and zymogram analysis revealed inhibition of MMP-9 expression by polyphenol treatment. Furthermore, AKT was found to be inhibited both at the RNA and protein level by polyphenol treatment. Moreover EGCG and GTP decreased AKT phosphorylation as found out by Western blotting for Phospho-AKT (Ser-473). beta-catenin level was found to be decreased both in cytoplasm and nucleus. For the first time we report the connection of beta-catenin and AKT modulation by GTP and EGCG as a possible mechanism for the induction of apoptosis in human breast cancer cells and also inhibition in their invasive capacity.

    Cancer biology & therapy 2007;6;12;1938-43

  • Nuclear beta-catenin staining and absence of steatosis are indicators of hepatocellular adenomas with an increased risk of malignancy.

    Van der Borght S, Libbrecht L, Katoonizadeh A, Aerts R, Nevens F, Verslype C and Roskams TA

    Histopathology 2007;51;6;855-6

  • An LRP5 receptor with internal deletion in hyperparathyroid tumors with implications for deregulated WNT/beta-catenin signaling.

    Björklund P, Akerström G and Westin G

    Department of Surgical Sciences, Uppsala University, Endocrine Unit, Uppsala University Hospital, Uppsala, Sweden.

    Background: Hyperparathyroidism (HPT) is a common endocrine disorder with incompletely understood etiology, characterized by enlarged hyperactive parathyroid glands and increased serum concentrations of parathyroid hormone and ionized calcium. We have recently reported activation of the Wnt signaling pathway by accumulation of beta-catenin in all analyzed parathyroid tumors from patients with primary HPT (pHPT) and in hyperplastic parathyroid glands from patients with uremia secondary to HPT (sHPT). Mechanisms that may account for this activation have not been identified, except for a few cases of beta-catenin (CTNNB1) stabilizing mutation in pHPT tumors.

    Reverse transcription PCR and Western blot analysis showed expression of an aberrantly spliced internally truncated WNT coreceptor low-density lipoprotein receptor-related protein 5 (LRP5) in 32 out of 37 pHPT tumors (86%) and 20 out of 20 sHPT tumors (100%). Stabilizing mutation of CTNNB1 and expression of the internally truncated LRP5 receptor was mutually exclusive. Expression of the truncated LRP5 receptor was required to maintain the nonphosphorylated active beta-catenin level, transcription activity of beta-catenin, MYC expression, parathyroid cell growth in vitro, and parathyroid tumor growth in a xenograft severe combined immunodeficiency (SCID) mouse model. WNT3 ligand and the internally truncated LRP5 receptor strongly activated transcription, and the internally truncated LRP5 receptor was insensitive to inhibition by DKK1.

    Conclusions: The internally truncated LRP5 receptor is strongly implicated in deregulated activation of the WNT/beta-catenin signaling pathway in hyperparathyroid tumors, and presents a potential target for therapeutic intervention.

    PLoS medicine 2007;4;11;e328

  • Activation of hepatic stem cell marker EpCAM by Wnt-beta-catenin signaling in hepatocellular carcinoma.

    Yamashita T, Budhu A, Forgues M and Wang XW

    Liver Carcinogenesis Section, Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892-4255, USA.

    The heterogeneous nature of hepatocellular carcinoma (HCC) and the lack of appropriate biomarkers have hampered patient prognosis and treatment stratification. Using a gene expression profiling approach, we recently identified a novel prognostic HCC subtype that resembles hepatic progenitor cells with the activation of stem cell markers and Wnt-beta-catenin signaling, based on EpCAM (epithelial cell adhesion molecule, a hepatic stem cell marker) expression. In this study, we investigated whether the activation of the Wnt-beta-catenin pathway regulates EpCAM expression. We found that nuclear accumulation of beta-catenin induced, whereas the degradation of beta-catenin or inhibition of Tcf/beta-catenin complex formation reduced EpCAM gene expression in cultured normal human hepatocytes and HCC cell lines. We identified two Tcf binding elements in the EpCAM promoter that specifically bound to Tcf-4 in an electrophoretic mobility shift assay. EpCAM promoter luciferase activity was down-regulated by the degradation of beta-catenin or inhibition of Tcf/beta-catenin complex formation. Furthermore, we found that EpCAM-positive HCC is much more sensitive to Tcf/beta-catenin binding inhibitors than EpCAM-negative HCC in vitro. Taken together, our data indicate that EpCAM is a Wnt-beta-catenin signaling target gene and may be used to facilitate HCC prognosis by enabling effective stratification of patients with predicted pharmacologic responses to Wnt-beta-catenin signaling antagonists.

    Funded by: Intramural NIH HHS

    Cancer research 2007;67;22;10831-9

  • KCl cotransporter-3 down-regulates E-cadherin/beta-catenin complex to promote epithelial-mesenchymal transition.

    Hsu YM, Chen YF, Chou CY, Tang MJ, Chen JH, Wilkins RJ, Ellory JC and Shen MR

    Institute of Basic Medical Sciences, Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.

    The potassium chloride cotransporter (KCC) is a major determinant of osmotic homeostasis and plays an emerging role in tumor biology. Here, we investigate if KCC is involved in the regulation of epithelial-mesenchymal transition (EMT), a critical cellular event of malignancy. E-cadherin and beta-catenin colocalize in the cell-cell junctions, which becomes more obvious in a time-dependent manner by blockade of KCC activity in cervical cancer SiHa and CaSki cells. Real-time reverse transcription-PCR on the samples collected from the laser microdissection indicates that KCC3 is the most abundant KCC isoform in cervical carcinoma. The characteristics of EMT appear in KCC3-overexpressed, but not in KCC1- or KCC4-overexpressed cervical cancer cells, including the elongated cell shape, increased scattering, down-regulated epithelial markers (E-cadherin and beta-catenin), and up-regulated mesenchymal marker (vimentin). Some cellular functions are enhanced by KCC3 overexpression, such as increased invasiveness and proliferation, and weakened cell-cell association. KCC3 overexpression decreases mRNA level of E-cadherin. The promoter activity assays of various regulatory sequences confirm that KCC3 expression is a potent negative regulator for human E-cadherin gene expression. The proteosome inhibitor restores the decreased protein abundance of beta-catenin by KCC3 overexpression. In the surgical specimens of cervical carcinoma, the decreased E-cadherin amount was accompanied by the increased KCC3 abundance. Vimentin begins to appear at the invasive front and becomes significantly expressed in the tumor nest. In conclusion, KCC3 down-regulates E-cadherin/beta-catenin complex formation by inhibiting transcription of E-cadherin gene and accelerating proteosome-dependent degradation of beta-catenin protein. The disruption of E-cadherin/beta-catenin complex formation promotes EMT, thereby stimulating tumor progression.

    Cancer research 2007;67;22;11064-73

  • beta-Catenin signaling in biological control and cancer.

    Gavert N and Ben-Ze'ev A

    Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel.

    A coordinated integration of cell-cell adhesion and the control of gene expression is essential for the development of multicellular, differentiated organisms. beta-Catenin fulfils important regulatory functions in both cell-cell adhesion by linking cadherin adhesion receptors to the cytoskeleton, and also as a key element in the Wnt signaling pathway where it acts as cotranscriptional activator of target genes in the cell nucleus. Wnt signaling is involved in numerous aspects of embryonic development and in the control of tissue self-renewal in a variety of adult tissues. Hyperactivation of Wnt signaling, mostly by affecting beta-catenin functions, is a hallmark of colon cancer and of many other human cancers. In this prospect, we discuss studies pointing to the molecular mechanisms that govern the integration between cell-cell adhesion and gene expression, as reflected in the switches between these two functions of beta-catenin in colon cancer cells.

    Journal of cellular biochemistry 2007;102;4;820-8

  • Beta-catenin signaling promotes proliferation of progenitor cells in the adult mouse subventricular zone.

    Adachi K, Mirzadeh Z, Sakaguchi M, Yamashita T, Nikolcheva T, Gotoh Y, Peltz G, Gong L, Kawase T, Alvarez-Buylla A, Okano H and Sawamoto K

    Department of Physiology, Keio University School of Medicine, Tokyo, Japan.

    The subventricular zone (SVZ) is the largest germinal zone in the mature rodent brain, and it continuously produces young neurons that migrate to the olfactory bulb. Neural stem cells in this region generate migratory neuroblasts via highly proliferative transit-amplifying cells. The Wnt/beta-catenin signaling pathway partially regulates the proliferation and neuronal differentiation of neural progenitor cells in the embryonic brain. Here, we studied the role of beta-catenin signaling in the adult mouse SVZ. beta-Catenin-dependent expression of a destabilized form of green fluorescent protein was detected in progenitor cells in the adult SVZ of Axin2-d2EGFP reporter mice. Retrovirus-mediated expression of a stabilized beta-catenin promoted the proliferation of Mash1+ cells and inhibited their differentiation into neuroblasts. Conversely, the expression of Dkk1, an inhibitor of Wnt signaling, reduced the proliferation of Mash1+ cells. In addition, an inhibitor of GSK3 beta promoted the proliferation of Mash1+ cells and increased the number of new neurons in the olfactory bulb 14 days later. These results suggest that beta-catenin signaling plays a role in the proliferation of progenitor cells in the SVZ of the adult mouse brain.

    Funded by: NICHD NIH HHS: HD32116; NIDDK NIH HHS: P30 DK063720

    Stem cells (Dayton, Ohio) 2007;25;11;2827-36

  • E-cadherin is required for caveolin-1-mediated down-regulation of the inhibitor of apoptosis protein survivin via reduced beta-catenin-Tcf/Lef-dependent transcription.

    Torres VA, Tapia JC, Rodriguez DA, Lladser A, Arredondo C, Leyton L and Quest AF

    FONDAP Center for Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Av. Independencia 1027, Santiago, Chile.

    Caveolin-1 reportedly acts as a tumor suppressor and promotes events associated with tumor progression, including metastasis. The molecular mechanisms underlying such radical differences in function are not understood. Recently, we showed that caveolin-1 inhibits expression of the inhibitor of apoptosis protein survivin via a transcriptional mechanism involving the beta-catenin-Tcf/Lef pathway. Surprisingly, while caveolin-1 expression decreased survivin mRNA and protein levels in HT29(ATCC) human colon cancer cells, this was not the case in metastatic HT29(US) cells. Survivin down-regulation was paralleled by coimmunoprecipitation and colocalization of caveolin-1 with beta-catenin in HT29(ATCC) but not HT29(US) cells. Unlike HT29(ATCC) cells, HT29(US) cells expressed small amounts of E-cadherin that accumulated in intracellular patches rather than at the cell surface. Re-expression of E-cadherin in HT29(US) cells restored the ability of caveolin-1 to down-regulate beta-catenin-Tcf/Lef-dependent transcription and survivin expression, as seen in HT29(ATCC) cells. In addition, coimmunoprecipitation and colocalization between caveolin-1 and beta-catenin increased upon E-cadherin expression in HT29(US) cells. In human embryonic kidney HEK293T and HT29(US) cells, caveolin-1 and E-cadherin cooperated in suppressing beta-catenin-Tcf/Lef-dependent transcription as well as survivin expression. Finally, mouse melanoma B16-F10 cells, another metastatic cell model with low endogenous caveolin-1 and E-cadherin levels, were characterized. In these cells, caveolin-1-mediated down-regulation of survivin in the presence of E-cadherin coincided with increased apoptosis. Thus, the absence of E-cadherin severely compromises the ability of caveolin-1 to develop activities potentially relevant to its role as a tumor suppressor.

    Molecular and cellular biology 2007;27;21;7703-17

  • Functional interaction of DNA topoisomerase IIalpha with the beta-catenin and T-cell factor-4 complex.

    Huang L, Shitashige M, Satow R, Honda K, Ono M, Yun J, Tomida A, Tsuruo T, Hirohashi S and Yamada T

    Chemotherapy Division and Cancer Proteomics Project, National Cancer Center Research Institute, Tokyo, Japan.

    The Wnt signaling pathway is activated constitutively in the majority of colorectal cancers as a result of mutation in either the adenomatous polyposis coli or the CTNNB1 gene, and blockage of the pathway has been considered feasible as molecular therapy against colorectal cancer. DNA topoisomerase IIalpha (Topo IIalpha) is a component of the beta-catenin/T-cell factor-4 (TCF-4) nuclear complex. We examined the functional significance of Topo IIalpha in Wnt signaling.

    Methods: The physical and functional interaction between Topo IIalpha and the beta-catenin/TCF-4 nuclear complex was evaluated by immunoprecipitation, immunofluorescence microscopy, 2-hybrid assay, and luciferase reporter assay.

    Results: Amino acids 951-1301 of Topo IIalpha were necessary for binding to beta-catenin. Over expression of Topo IIalpha enhanced the TCF/lymphoid enhancer factor transcriptional activity in a dose-dependent manner, and knockdown of Topo IIalpha by RNA interference conversely attenuated the transcriptional activity. The Topo II inhibitors, merbarone and etoposide, suppressed the beta-catenin-mediated TCF/lymphoid enhancer factor transcriptional activity. The catalytic activity of Topo II was augmented by overexpression of beta-catenin as measured by the decatenation of kinetoplast DNA. Topo IIalpha was highly expressed and colocalized with beta-catenin in tumor cells of patients with familial adenomatous polyposis syndrome and patients with sporadic colorectal cancer.

    Conclusions: Topo IIalpha interacts with beta-catenin as a novel transcriptional co-activator. A new drug targeting the interaction of Topo IIalpha with beta-catenin as well as its catalytic activity might be more effective for suppressing aberrant Wnt signaling and proliferation of colorectal cancer cells than the current Topo II inhibitors.

    Gastroenterology 2007;133;5;1569-78

  • Genetically distinct and clinically relevant classification of hepatocellular carcinoma: putative therapeutic targets.

    Katoh H, Ojima H, Kokubu A, Saito S, Kondo T, Kosuge T, Hosoda F, Imoto I, Inazawa J, Hirohashi S and Shibata T

    Cancer Genomics Project, National Cancer Center Research Institute, Tokyo, Japan; Pathology Division, National Cancer Center Research Institute, Tokyo, Japan.

    The biological aggressiveness of hepatocellular carcinoma (HCC) and the lack of optimal therapeutic strategies have rendered the disease a major challenge. Highly heterogeneous genetic alteration profiles of HCC have made it difficult to identify effective tailor-made molecular therapeutic targets. Therefore, classification of HCC into genetically homogeneous subclasses would be of great worth to develop novel therapeutic strategies.

    Methods: We clarified genome-scale chromosomal copy number alteration profiles and mutational statuses of p53 and beta-catenin in 87 HCC tumors. We investigated the possibility that HCC might be classifiable into a number of homogeneous subclasses based solely on their genetic alteration profiles. We also explored putative molecular therapeutic targets specific for each HCC subgroup.

    Results: Unsupervised hierarchical cluster analysis based on chromosomal alteration profiles suggested that HCCs with heterogeneous genetic backgrounds are divisible into homogeneous subclasses that are highly associated with a range of clinicopathologic features of the tumors and moreover with clinical outcomes of the patients (P < .05). These genetically homogeneous subclasses could be characterized distinctively by pathognomonic chromosomal amplifications (eg, c-Myc-induced HCC, 6p/1q-amplified HCC, and 17q-amplified HCC). An in vitro experiment raised a possibility that Rapamycin would significantly inhibit the proliferative activities of HCCs with 17q amplification.

    Conclusions: HCC is composed of several genetically homogeneous subclasses, each of which harbors characteristic genetic alterations that can be putative tailor-made molecular therapeutic targets for HCCs with specific genetic backgrounds. Our results offer an opportunity for developing novel individualized therapeutic modalities for distinctive genome types of HCC.

    Gastroenterology 2007;133;5;1475-86

  • Sox17 and Sox4 differentially regulate beta-catenin/T-cell factor activity and proliferation of colon carcinoma cells.

    Sinner D, Kordich JJ, Spence JR, Opoka R, Rankin S, Lin SC, Jonatan D, Zorn AM and Wells JM

    Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229-3039, USA.

    The canonical Wnt pathway is necessary for gut epithelial cell proliferation, and aberrant activation of this pathway causes intestinal neoplasia. We report a novel mechanism by which the Sox family of transcription factors regulate the canonical Wnt signaling pathway. We found that some Sox proteins antagonize while others enhance beta-catenin/T-cell factor (TCF) activity. Sox17, which is expressed in the normal gut epithelium but exhibits reduced expression in intestinal neoplasia, is antagonistic to Wnt signaling. When overexpressed in SW480 colon carcinoma cells, Sox17 represses beta-catenin/TCF activity in a dose-dependent manner and inhibits proliferation. Sox17 and Sox4 are expressed in mutually exclusive domains in normal and neoplastic gut tissues, and gain- and loss-of-function studies demonstrate that Sox4 enhances beta-catenin/TCF activity and the proliferation of SW480 cells. In addition to binding beta-catenin, both Sox17 and Sox4 physically interact with TCF/lymphoid enhancer factor (LEF) family members via their respective high-mobility-group box domains. Results from gain- and loss-of-function experiments suggest that the interaction of Sox proteins with beta-catenin and TCF/LEF proteins regulates the stability of beta-catenin and TCF/LEF. In particular, Sox17 promotes the degradation of both beta-catenin and TCF proteins via a noncanonical, glycogen synthase kinase 3beta-independent mechanism that can be blocked by proteasome inhibitors. In contrast, Sox4 may function to stabilize beta-catenin protein. These findings indicate that Sox proteins can act as both antagonists and agonists of beta-catenin/TCF activity, and this mechanism may regulate Wnt signaling responses in many developmental and disease contexts.

    Funded by: NICHD NIH HHS: HD42572, R01 HD042572-04, R01 HD042572-05, T32 HD07463; NIGMS NIH HHS: GM072915

    Molecular and cellular biology 2007;27;22;7802-15

  • Down-regulation of MUC1 in cancer cells inhibits cell migration by promoting E-cadherin/catenin complex formation.

    Yuan Z, Wong S, Borrelli A and Chung MA

    Department of Surgery, Rhode Island Hospital, Brown University, 2 Dudley Street, Suite 470, Providence, RI 02905, USA.

    MUC1, a tumor associated glycoprotein, is over-expressed in most cancers and can promote proliferation and metastasis. The objective of this research was to study the role of MUC1 in cancer metastasis and its potential mechanism. Pancreatic (PANC1) and breast (MCF-7) cancer cells with stable 'knockdown' of MUC1 expression were created using RNA interference. beta-Catenin and E-cadherin protein expression were upregulated in PANC1 and MCF-7 cells with decreased MUC1 expression. Downregulation of MUC1 expression also induced beta-catenin relocation from the nucleus to the cytoplasm, increased E-cadherin/beta-catenin complex formation and E-cadherin membrane localization in PANC1 cells. PANC1 cells with 'knockdown' MUC1 expression had decreased in vitro cell invasion. This study suggested that MUC1 may affect cancer cell migration by increasing E-cadherin/beta-catenin complex formation and restoring E-cadherin membrane localization.

    Biochemical and biophysical research communications 2007;362;3;740-6

  • The significance of beta-catenin, E-cadherin, and P-cadherin expressions in neoplastic progression of colorectal mucosa: an immunohistochemical study.

    Savas B, Ensari A, Percinel S, Kuzu I, Kuzu MA, Bektas M, Cetinkaya H and Kursun N

    Ankara University Medical Faculty, Ankara, Turkey.

    The purpose of the current study was to investigate the role of beta-catenin, E-cadherin and P-cadherin in colorectal carcinogenesis using tissue array method.

    Core tissue biopsies were taken from paraffin-embedded tissue blocks of 167 cases including 26 normal mucosae (NM), 99 colorectal polyps (10 hyperplastic polyps (HP), 8 traditional serrated (TSA), 17 tubular (TA), 37 tubulovillous (TVA), and 27 villous adenomas (VA)), 14 adenomas with intramucosal carcinoma (ACA), and 28 colorectal cancers (CCA). Immunohistochemistry was performed using antibodies to beta-catenin, E-cadherin, and P-cadherin. Distribution of positivity was assessed using percentage expression while an arbitrary grading scale was used for staining intensity.

    Results: beta-catenin expression was cytoplasmic, membranous, and nuclear. Both E-cadherin and P-cadherin expressions were confined to cytoplasmic-membranous compartments. Membranous expression of beta-catenin significantly decreased in CCA (p < 0.01). Nuclear beta-catenin expression significantly increased in close correlation with neoplastic sequence reaching its highest expression in ACA and CCA (p < 0.001). Polyps with intraepithelial neoplasia (IEN) showed significantly higher nuclear beta-catenin expression in parallel with increasing grades of IEN (p < 0.001). E-cadherin and P-cadherin expression increased in polyps, whereas a significant decrease in their expression was observed in CCA (p < 0.001) while E-cadherin expression significantly increased in CCA compared to NM (p < 0.001), no such difference was observed in P-cadherin expression.

    Conclusions: Nuclear beta-catenin expression correlating with the grade of IEN in polyps and carcinomas supports its role in colorectal carcinogenesis. E-cadherin and P-cadherin expressions in adenomas suggest that these molecules might have role in adenoma formation though not necessarily be involved in neoplastic progression.

    Acta gastro-enterologica Belgica 2007;70;4;339-44

  • Epstein-Barr virus, beta-catenin, and E-cadherin in gastric carcinomas.

    Jung IM, Chung JK, Kim YA, Kim JE, Heo SC, Ahn YJ, Hwang KT, Kim BG, Lee KL, Kim CW, Kim WH and Chang MS

    Department of Surgery, Seoul National University Boramae Hospital, Seoul, Korea.

    Activated beta-catenin is suggested to inhibit NF-kappaB activation, and we previously demonstrated that NF-kappaB nuclear positivity was more frequent in Epstein-Barr virus (EBV)-infected gastric carcinomas. It is controversial that beta-catenin and E-cadherin are prognostic markers in gastric carcinomas. To define a relationship between beta-catenin and EBV, and the prognostic value of beta-catenin and E-cadherin, we analyzed in situ hybridization for EBV-encoded small RNAs, beta-catenin, and E-cadherin immunohistochemistry, and clinicopathological features in 111 gastric carcinomas. EBV infection was detected in seven carcinomas (6.3%); none of seven showed beta-catenin nuclear accumulation, and five out of seven revealed beta-catenin membranous loss or cytoplasmic expression. Eighty cases (72.1%) showed beta-catenin alteration; i.e., loss of membrane staining in 65 (58.6 %), cytoplasmic expression in 35 (31.5%), and nuclear accumulation in 15 (13.5%). E-cadherin alteration was observed in 34 cases (30.6%) and correlated with beta-catenin alteration. On multivariate analysis, the combined immunoexpression group of beta-catenin nuclear accumulation/ E-cadherin alteration and the advanced TNM cancer stage group showed poor patient's survival (p<0.05). In conclusion, beta-catenin activation through nuclear accumulation hardly occurred in EBV-infected gastric carcinomas. The combined immunoexpression pattern of beta-catenin and E-cadherin can be used as a prognostic marker in gastric carcinomas.

    Journal of Korean medical science 2007;22;5;855-61

  • [Expression and exon 3 mutation of beta-catenin in human hepatocellular carcinoma].

    Jiao Y, Ban KC, Cao J, Yue HY, Luo Y and Su JJ

    Department of Pharmacology, Guangxi Medical University, Nanning, Guangxi, 530021, P. R. China.

    South Guangxi is an area with high incidence of hepatocellular carcinoma (HCC), and with severe contamination of dietary aflatoxin B1 (AFB1). The activation of beta-Catenin is involved in many cancers. AFB1 may play a key role in hepatocarcinogenesis. This study was to explore the expression and mutation of beta-Catenin in HCC patients from the area with high exposure level of AFB1.

    Methods: The expression of beta-Catenin in 52 specimens of HCC and para-HCC tissues, and 18 specimens of non-cancerous liver tissues from South Guangxi were detected by direct sequencing, reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot.

    Results: No mutation in exon 3 of beta-Catenin gene was found in HCC tissues. The mRNA level of beta-Catenin was significantly higher in HCC tissues than in para-HCC tissues and non-cancerous tissues (0.42+/-0.24 vs. 0.20+/-0.16 and 0.23+/-0.12, P<0.01). The positive rate of beta-Catenin was significantly higher in HCC tissues than in para-HCC tissues (55.8% vs. 36.5%, P<0.05). The expression of beta-Catenin mRNA showed no significant correlation to clinicopathologic parameters of HCC (all P>0.05), while the expression of beta-Catenin protein was significantly correlated to metastasis, relapse, portal vein embolus, and clinical stage (all P<0.05).

    Conclusion: Beta-catenin is overexpressed in HCC, but its overexpression has no correlation to gene mutation at GSK-3beta phosphorylation sites in exon 3.

    Ai zheng = Aizheng = Chinese journal of cancer 2007;26;10;1085-9

  • [Expression of beta-Catenin Gene in CML and its relationship with bcr/abl].

    Li ZJ, Qiu LG, Li X, Mai YJ, Wang GR, Yu Z, Wang YF, Li CH and Li Q

    State Key Laboratory of Experimental Hematology, Institute of Hematology, Blood Disease Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Tianjin 300020, China.

    This study was aimed to quantitatively detect the expression level of beta-catenin and bcr/abl in different phases of chronic myeloid leukemia (CML) and to analyze their potential relationship and significance in the progression of CML. First, the total RNA isolated from BMMNC of patients with CML and donors was reversely transcribed into cDNA. The real-time quantitative PCR method was used to analyze the expression level of beta-catenin and bcr/abl. The expression level of beta-catenin and bcr/abl in different phases of CML was compared and the correlation was analyzed between the two genes. The results showed that the beta-catenin gene in BMMNC of blast crisis of CML patients was expressed significantly higher than that in chronic phase (p < 0.001) and accelerated phase (p = 0.016) of CML patients and in normal donors (p = 0.004). The expression of bcr/abl in blast crisis of CML was statistically higher than that in chronic phase of CML (p = 0.001). The expression levels of beta-catenin and bcr/abl were correlated with each other in CML patients (r = 0.620, p < 0.001). It is concluded that the beta-catenin gene in blast crisis of CML patients express higher than that in chronic phase and accelerated phase of CML, and its expression level is correlated with the level of bcr/abl expression. The increased expression of beta-catenin may be account partly for the blast crisis of CML.

    Zhongguo shi yan xue ye xue za zhi 2007;15;5;931-5

  • [Expression of beta-Catenin in Leukemic Cell Lines].

    Mai YJ, Qiu LG, Li ZJ, Li X, Wang GR, Yu Z, Xu Y, Wang YF and Li Q

    State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Tianjin 300020, China

    This study was aimed to investigate the expression of beta-catenin in leukemic cell lines and its relationship with pathogenesis of leukemia, semi-quantitative RT-PCR and Western blot were performed to detect the expression of beta-catenin in a panel of 15 human hematopoietic cell lines (U937, KG1a, Jurkat, K562, Namalwa, HEL, HUT78, Raji, Daudi, CEM, LCL-H, HL-60, NB4, J6-1, Ramos). Immunocytochemistry was performed in some of these cell lines to detect the location of beta-catenin. The results showed that the beta-catenin gene was widely expressed in most leukemic cell lines in various degree, the high expression of beta-catenin was found is U937, KG1a, Jurkat, K562 and Namalwa cells, middle expression of beta-catenin was observed in HEL, HUT78, Raji, Daudi and CEM cells, lower expression of beta-catenin was observed in LCL-H, HL-60, NB4, J6-1 and Ramos cells. The expression level of beta-catenin protein was identical to the expression level of beta-catenin mRNA. The expression of beta-catenin could be found in nuclei of all cells mentioned above, but their levels were different between them. Abundant beta-catenin also could be observed in nuclei of some leukemic cells by immunocytochemistry. It is concluded that overexpression of beta-catenin in leukemia cells, as a key mediator of Wnt signaling transduction pathway, indicates that the Wnt signaling transduction pathway may be aberrantly activated in leukemia.

    Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 2007;15;5;919-22

  • Inositol pentakisphosphate mediates Wnt/beta-catenin signaling.

    Gao Y and Wang HY

    Department of Physiology and Biophysics, Diabetes and Metabolic Disease Research Center, School of Medicine, Health Sciences Center, State University of New York, Stony Brook, New York 11794-8661, USA.

    Wnt3a stimulates lymphoid enhancer factor/T-cell factor protein-sensitive transcription, i.e. the canonical pathway, in mouse F9 embryonal tetratocarcinoma cells expressing rat Frizzled-1. We explored the potential roles for inositol polyphosphates as mediators of Wnt signaling in the canonical path-way. Wnt3a triggers G-protein-linked phosphatidylinositol signaling, transiently generating inositol polyphosphates, especially inositol pentakisphosphate (IP(5)) accumulation. Knock-down of Galpha(q) abolishes, whereas expression of the Q209L constitutively active mutant of Galpha(q) mimics, the effects of Wnt3a on IP(5) generation and downstream signaling. Phospholipase Cbeta-1 and Cbeta-3 mediate the G protein signal to the level of phosphatidylinositol signaling. Knock-down and inhibitor studies of the enzymes responsible for generating IP(5) reveal inositol 1,4,5-trisphosphate 3-kinase and inositol polyphosphate multikinase as key mediators in the production of IP(5). Wnt3a stimulation of the canonical pathway requires accumulation of IP(5), which acts to inhibit the activity of glycogen synthase kinase-3beta, whereas stimulating casein kinase 2. Blockade of Wnt3a stimulation of IP(5) generation blocks beta-catenin accumulation, activation of lymphoid enhancer factor/T-cell factor protein-sensitive transcription, and promotion of primitive endoderm formation in response to Wnt3a. Phosphatidylinositol signaling mediates Wnt3a action in the canonical pathway, acting to generate inositol pentakisphosphate, a key second messenger of Wnt3a.

    Funded by: NIGMS NIH HHS: GM 069375

    The Journal of biological chemistry 2007;282;36;26490-502

  • Detection of beta-catenin mutations in paraffin-embedded sporadic desmoid-type fibromatosis by mutation-specific restriction enzyme digestion (MSRED): an ancillary diagnostic tool.

    Amary MF, Pauwels P, Meulemans E, Roemen GM, Islam L, Idowu B, Bousdras K, Diss TC, O'Donnell P and Flanagan AM

    Department of Histopathology, Santa Casa School of Medical Sciences, Sao Paulo, Brazil.

    Desmoid-type fibromatosis is a locally aggressive deep soft tissue tumor. Some cases are associated with adenosis polyposis coli germline mutations whereas others harbor somatic beta-catenin point mutations mainly in exon 3, codons 41 and 45. These mutations result in stabilization of beta-catenin, and activation of the Wnt signaling pathway. The aim of this study was to determine the specificity and sensitivity of these 3 most common beta-catenin mutations in the diagnosis of desmoid-type fibromatosis using paraffin-embedded material. The results were compared with nuclear expression of beta-catenin. Mutation-specific restriction enzyme digestion methodology was employed to detect the 3 mutations. One hundred and thirty-three cases were analyzed, including 76 desmoid-type, and 18 superficial fibromatosis, in addition to a further 39 fibromatosis mimics. A restriction site was present for analysis of the codon 41 mutation. Mismatch primers were designed for the codon 45 mutations. Mutations were detected in 66 cases (87%) of 76 desmoid-type fibromatosis (71 extra-abdominal). Of these, 34 (45%) were in codon 45 (TCT>TTT), 27 (35%) in codon 41 (ACC>GCC), and 5 (7%) in codon 45 (TCT>CCT). No mutations were detected in the other lesions studied. All desmoid-type fibromatosis cases and 72% of the mimics tested showed nuclear positivity for beta-catenin indicating immunohistochemistry is a sensitive but not a specific test for desmoid-type fibromatosis. In contrast, to date, beta-catenin mutations have not been detected in any lesions which mimic desmoid-type fibromatosis. Mutation-specific restriction enzyme digestion, a simple and efficient means of detecting the common beta-catenin mutations in desmoid-type fibromatosis, complements light microscopy in reaching a diagnosis.

    The American journal of surgical pathology 2007;31;9;1299-309

  • Downregulation of beta-catenin and transdifferentiation of human osteoblasts to adipocytes under estrogen deficiency.

    Foo C, Frey S, Yang HH, Zellweger R and Filgueira L

    School of Anatomy and Human Biology, The University of Western Australia, Perth, Australia.

    Postmenopausal osteoporosis, caused by estrogen deficiency, is characterized by the structural deterioration of bone accompanied by an increase in bone marrow adipocytes. Transgenic animal models have shown that there is a reciprocal relationship between osteoblastogenesis and adipogenesis in vivo. The present study investigated whether the estrogen and the canonical Wnt signaling pathways are linked together and regulate the phenotype and function, differentiation and proliferation of human osteoblasts using an in vitro estrogen-deficiency model.

    Methods: Human osteoblasts (hFOB 1.19) and fulvestrant, an estrogen receptor blocker, were used to mimic estrogen deficiency in vitro. Osteogenic and adipogenic differentiation was measured by using specific stains and microscopy, as well as by measuring the expression of bone cell-specific markers with reverse transcription polymerase chain reaction. Expression of estrogen receptor-alpha (ERalpha) and beta-catenin was detected in Western blots and by immunoprecipitation.

    Results: The cells expressed the 46-kDa and the 77-kDa ERalpha isoforms and beta-catenin. Fulvestrant reduced expression of ERalpha and beta-catenin. beta-Catenin was co-immunoprecipitated with ERalpha, indicating that these two proteins form a new signaling complex and transcription factor. In addition, it induced intracellular lipid droplet accumulation and downregulation of bone cell markers, indicating adipocyte differentiation.

    Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology 2007;23;9;535-40

  • [Expression and clinical significance of beta-catenin in multiple myeloma].

    Li J, Zhang DB, Luo SK, Zhao Y, Huang BH and Gu JL

    Department of Hematology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510080, PR China. luliyuan@tom.com

    beta-catenin is the pivotal regulator in Wnt pathway and in charge of cellular adhesion and signal conduction. Overexpression of beta-catenin has been observed in various human tumors. This study was to investigate the expression and clinical significance of beta-catenin in multiple myeloma (MM).

    Methods: Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect mRNA and protein expression of beta-catenin in bone marrow samples from 12 newly diagnosed MM patients, 14 relapsed/refractory MM patients, and 11 healthy donors. The clinical data and treatment outcomes of the MM patient were also analyzed.

    Results: The positive rate and the expression level of beta-catenin mRNA were significantly lower in healthy donors than in newly diagnosed patients and relapsed/refractory patients (27.3% vs. 75.0% and 100%, P=5.01e(-4); 0.35+/-0.17 vs. 0.72+/-0.11 and 0.85+/-0.16, P=5.88e(-5)); the mRNA level of beta-catenin was significantly lower in newly diagnosed patients than in relapsed/refractory patients (P=0.045). beta-catenin protein was not detected in healthy donors; while the positive rate and the expression level of beta-catenin protein were significantly lower in newly diagnosed patients than in relapsed/refractory patients (50.0% vs. 85.7%, 0.32+/-0.11 vs. 0.21+/-0.08, P=0.039). In the 10 newly diagnosed MM patients with evaluable treatment outcomes, the positive rate of beta-catenin protein was significant lower in the 7 patients without response than in the 3 patients showed response (14.3% vs. 100%, P=0.033). The positive rate of beta-catenin protein was significant higher in the 16 Durie/Salmon stage III patients than in the 10 stage II patients (87.5% vs. 40.0%, P=0.026), and significant higher in ISS stage III patients than in stage I and II patients (100% vs. 45.5% and 33.3%, P=0.006, P=0.032). The protein level of beta-catenin was positively correlated to serum levels of beta2-MG (r=0.688, P=0.002) and lactate dehydrogenase (LDH) (r=0.502, P=0.034).

    Conclusion: The expression of beta-catenin is related with treatment outcome, Durin-Salmon stage and ISS stage of MM, and is positively correlated to serum levels of LDH and beta2-MG.

    Ai zheng = Aizheng = Chinese journal of cancer 2007;26;9;1010-4

  • [Expression and significance of APC, beta-catenin, C-myc, and Cyclin D1 proteins in colorectal carcinoma].

    Dai WB, Ren ZP, Chen WL, DU J, Shi Z and Tang DY

    Department of Pathology, People's Hospital of Liuzhou City, Liuzhou, Guangxi, 545001, PR China. daiwenbin1973@sina.com

    The abnormal oncogenes and antioncogenes in Wnt signaling transduction pathway activate downstream specific target genes, and may play important roles in tumorigenesis and tumor progression. This study was to examine the expression of adenomatous polyposis coli (APC), beta-catenin, C-myc, and Cyclin D1 in different colorectal tissues, and investigate their possible roles in the carcinogenesis of colorectal carcinoma.

    Methods: The expression of APC, beta-catenin, C-myc, and Cyclin D1 in 30 specimens of normal colorectal mucosa, 30 specimens of colorectal adenoma, 10 specimens of colorectal adenoma with malignancy, and 50 specimens of colorectal carcinoma was examined by immunohistochemistry. The expression of beta-catenin on cell membrane was regarded as normal, and its expression in cytoplasm and nuclei was defined as ectopic expression.

    Results: The positive rate of APC was significantly lower in colorectal carcinoma and colorectal adenoma with malignancy than in colorectal adenoma and normal colorectal mucosa (44.0% and 40.0% vs. 86.7% and 100.0%, P<0.01). The ectopic expression rate of beta-catenin was significantly higher in colorectal carcinoma, colorectal adenoma with malignancy, and colorectal adenoma than in normal colorectal mucosa (62.0%, 50.0%, and 30.0% vs. 0%, P<0.01), and significantly higher in colorectal carcinoma than in colorectal adenoma (P<0.01). The positive rate of C-myc was significantly higher in colorectal carcinoma, colorectal adenoma with malignancy, and colorectal adenoma than in normal colorectal mucosa (56.0%, 60.0%, and 46.7% vs. 0%, P<0.01). The positive rate of Cyclin D1 was significantly higher in colorectal carcinoma, colorectal adenoma with malignancy, and colorectal adenoma than in normal colorectal mucosa (66.0%, 60.0%, and 30.0% vs. 0%,P<0.01), and significantly higher in colorectal carcinoma than in colorectal adenoma (P<0.01). The ectopic expression of beta-catenin was positively correlated to the expression of C-myc and Cyclin D1 (r=0.63,P<0.01; r=0.57, P<0.01), and negatively correlated to the expression of APC (r=-0.39, P<0.05).

    Conclusion: The reduced expression of APC, ectopic expression of beta-catenin, overexpression of C-myc and Cyclin D1 exist in colorectal carcinoma, which may play important roles in the carcinogenesis of colorectal carcinoma.

    Ai zheng = Aizheng = Chinese journal of cancer 2007;26;9;963-6

  • HER-2/neu transcriptionally activates Jab1 expression via the AKT/beta-catenin pathway in breast cancer cells.

    Hsu MC, Chang HC and Hung WC

    College of Medicine, Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.

    Jab1 is a co-activator of activating protein-1 (AP-1) transcription factor and the fifth subunit of the constitutive photomorphogenesis 9 (COP9) signalosome, which has been shown to mediate nuclear exportation and ubiquitin-dependent degradation of the tumor suppressor p27(Kip1). Jab1 is overexpressed in several types of human cancer. However, de-regulation of Jab1 gene expression in cancer cells is largely unclear. In this study, we reported that expression of Jab1 was stimulated by HER-2/neu oncogene via transcriptional activation. Promoter deletion and mutation analysis indicated that HER-2/neu stimulated Jab1 via the T cell factor (TCF) binding site located at the -380/-368 region of the human Jab1 promoter. DNA affinity precipitation assay and chromatin immunoprecipitation assay verified that binding of beta-catenin and TCF-4 to this consensus site was increased by HER-2/neu. In addition, dominant-negative mutant of TCF significantly attenuated the stimulatory effect of HER-2/neu. We also demonstrated that HER-2/neu increased beta-catenin/TCF-mediated Jab1 expression via the AKT signaling pathway because chemical inhibitor or dominant-negative mutant of AKT effectively attenuated the stimulatory action of HER-2/neu. IGF-I, which is a well-known AKT activator, also up-regulated the expression of Jab1 in NIH/3T3 and MCF-7 cells. Knockdown of Jab1 by small interfering RNA (siRNA) preferentially inhibited proliferation of HER-2/neu-overexpressing breast cancer cells. Taken together, our results suggest that HER-2/neu transcriptionally activates Jab1 expression to promote proliferation of breast cancer cells.

    Endocrine-related cancer 2007;14;3;655-67

  • Interaction of MUC1 with beta-catenin modulates the Wnt target gene cyclinD1 in H. pylori-induced gastric cancer.

    Udhayakumar G, Jayanthi V, Devaraj N and Devaraj H

    Department of Zoology, Unit of Biochemistry, University of Madras, Guindy Campus, Chennai, India.

    Beta-catenin can function as an oncogene when it is translocated to the nucleus, binds to T-cell factor (TCF) or lymphoid enhance factor and transactivate its target gene. The mechanism responsible for the activation of Wnt signaling pathway in the Cytotoxin-associated antigen A (CagA) Helicobacter pylori (H. pylori)-infected gastric carcinoma has not been elucidated. We hypothesize that whether interaction of MUC1 with beta-catenin modulates the Wnt signaling and its target gene cyclinD1 in CagA H. pylori-infected gastric carcinoma. The result demonstrate that binding of MUC1 CT with Protein Kinase C delta (PKC delta), tyrosine phosphorylation of MUC1 CT, and CagA are strongly associated with the interaction of MUC1 with beta-catenin in CagA H. pylori-infected gastric carcinoma. A statistically significant difference (chi(2) = 24.49; P < 0.001) was found when the binding of MUC1 CT and beta-catenin was compared to subcellular localization of beta-catenin. We also observed significant statistical correlation (chi(2) = 14.885; P < 0.001) between the cyclinD1 overexpression and the subcellular localization of beta-catenin. The overexpression of cyclinD1 was significantly higher (chi(2) = 13.785; P < 0.002) in advanced gastric carcinoma with CagA H. pylori infection. In addition cyclinD1 overexpression was significantly higher (chi(2) = 37.267; P < 0.001) with the interaction of MUC1 CT with beta-catenin in advanced gastric cancer. These findings indicate that MUC1 CT plays a role in the intracellular signaling through its interaction with beta-catenin and upregulate the Wnt target gene cyclinD1 in CagA H. pylori-infected gastric carcinoma.

    Molecular carcinogenesis 2007;46;9;807-17

  • Sequential WT1 and CTNNB1 mutations and alterations of beta-catenin localisation in intralobar nephrogenic rests and associated Wilms tumours: two case studies.

    Fukuzawa R, Heathcott RW, More HE and Reeve AE

    Cancer Genetics Laboratory, Department of Biochemistry, University of Otago, Dunedin, New Zealand. ryuji.fukuzawa@stonebow.otago.ac.nz

    Background: Intralobar nephrogenic rests (ILNRs) are precursor lesions for Wilms tumours and are associated with WT1 gene mutations. ILNR-associated Wilms tumours have a co-clustering of WT1 and beta-catenin (CTNNB1) mutations and unique histological features characterised by a stromal-predominant histology.

    Aim: To determine the order in which WT1 and CTNNB1 mutations occur to understand the ILNR-Wilms tumour sequence.

    Methods: Of nine Wilms tumours with WT1 and CTNNB1 mutations, three ILNRs lesions in two Wilms tumours were available for analysis of WT1 and CTNNB1 mutations using microdissection. Immunohistochemistry was also performed to investigate how the mutations in beta-catenin alter the localisation in Wilms tumour development.

    Results: WT1 mutations were present in the ILNRs, however CTNNB1 mutations were absent. Immunohistochemistry for WT1 confirmed inactivation of WT1 in both ILNRs and Wilms tumours. Both the ILNRs and the associated Wilms tumours had similar immunostaining patterns for beta-catenin in the blastemal and epithelial components. Although rhabdomyoblasts were not included in ILNRs, the associated Wilms tumours showed rhabdomyogenic differentiation with a positive beta-catenin nuclear staining.

    Conclusions: The results suggest that CTNNB1 mutation is a later event in Wilms tumourigenesis. CTNNB1 mutations might be associated with rhabdomyogenesis.

    Journal of clinical pathology 2007;60;9;1013-6

  • E-cadherin and beta-catenin expression in Epstein-Barr virus-associated gastric carcinoma and their prognostic significance.

    Koriyama C, Akiba S, Itoh T, Sueyoshi K, Minakami Y, Corvalan A, Yonezawa S and Eizuru Y

    Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan. akiba@m.kufm.kagoshima-u.ac.jp

    Aim: To examine the role of E-cadherin and beta-catenin in carcinogenesis and to assess their prognostic implication in Epstein-Barr virus-associated gastric carcinomas (EBV-GCs).

    Methods: We compared the frequency of E-cadherin and beta-catenin expression in 59 EBV-GCs and 120 non-EBV-GCs, and examined the association between patients' prognosis and the expressions of these proteins.

    Results: Neither the cellular-membranous nor the cytoplasmic E-cadherin expression showed any difference between EBV-GCs and non-EBV-GCs. On the other hand, loss of membranous expression of beta-catenin occurred more frequently in non-EBV-GCs than EBV-GCs [odds ratio = 0.41; 95% confidence interval (CI), 0.19-0.90]. Furthermore, the nuclear and/or cytoplosmic expression of beta-catenin was seen more frequently in EBV-GCs than non-EBV-GCs (odds ratio = 2.23; 95% CI, 0.97-5.09), and was observed in a larger proportion of carcinoma cells of EBV-GCs than non-EBV-GCs (P = 0.024). Survival analysis for non-EBV-GC revealed that lymph node metastasis was significantly associated with poor prognosis (P < 0.001). Among EBV-GCs, the depth of invasion (P = 0.005), lymph node metastasis (P = 0.004) and an intestinal type by Lauren classification (hazard ratio = 9.47; 95% CI, 2.67-33.6) were significantly associated with poor prognosis. On the other hand, nuclear and/or cytoplasmic expression of beta-catenin was associated with a better prognosis in patients with EBV-GC (hazard ratio = 0.32; 95% CI, 0.11-0.93).

    Conclusion: We observed more frequent preservation of beta-catenin in cell membrane and accumulation in nuclei and/or cytoplasm in EBV-GCs than in non-EBV-GCs. Factors involved in the prognosis of EBV-GCs and non-EBV-GCs are different in the two conditions.

    World journal of gastroenterology 2007;13;29;3925-31

  • TGF-beta modulates beta-Catenin stability and signaling in mesenchymal proliferations.

    Amini Nik S, Ebrahim RP, Van Dam K, Cassiman JJ and Tejpar S

    Department of Human Genetics, Catholic University of Leuven, Herestraat 49, Leuven, Belgium.

    Here for the first time we showed, despite the oncogenic mutations in beta-Catenin, that TGF-beta is a modulator of beta-Catenin levels in tumoral fibroblasts as well as non-tumoral fibroblasts. The results show that the TGF-beta pathway is active in desmoids cells and in in situ tumors. A dose dependent increase in beta-Catenin protein levels was observed after TGF-beta treatment in combination with an increased repression of GSK-3beta both in normal and tumoral fibroblasts. TGF-beta stimulation also led to an altered -- up to 5 fold -- transcriptional activity of beta-Catenin responsive promoters, such as IGFBP6 as well as increase of TOPflash activity. TGF-beta stimulation increased cell proliferation and BrdU incorporation 2.5 times. Taken together, we propose that TGF-beta is a modulator of beta-Catenin levels in tumoral fibroblasts and non-tumoral fibroblasts, despite the oncogenic mutations already present in this gene in tumoral fibroblasts of desmoid tumors. This modulation of beta-Catenin levels by TGF-beta may be involved in determining the tumoral phenotype of the cells.

    Experimental cell research 2007;313;13;2887-95

  • [The expression of beta-catenin and its significance in leukemia cells].

    Mai YJ, Qiu LG, Li ZJ, Yu Z, Li CH, Wang YF, Wang GR and Li Q

    State Key Laboratory of Experimental Hematology, Institute of Hematology, Blood Diseases Hospital, CAMS & PUMC, Tianjin, China.

    Objective: To investigate the expression of beta-catenin in patients with leukemia and explore its significance in leukemias.

    Methods: RT-PCR was used to detect the expression of beta-catenin in bone marrow mononuclear cells (BMMNCs) from patients with leukemia. Immunocytochemistry was in some of patients to detect the distribution of beta-catenin at the same time. The clinical significance of beta-catenin was analyzed in combination with patients' clinical information.

    Results: Expression of beta-catenin was statistically higher in acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) samples than in normal donors (P = 0.001 and 0.016 respectively) and chronic phase chronic myeloid leukemia (CML) patients (P = 0.001 and P = 0.008 respectively), while there was no statistic difference between AML and ALL patients (P = 0.58). In addition, beta-catenin expression in chronic phase CML patients was like that in normal donors (P = 0.49), but increased significantly in blast crisis and accelerated phase. Immunocytochemical analysis revealed that BMMNCs from normal donors expressed beta-catenin on the plasma membrane and cytoplasma, while those from acute leukemia expressed beta-catenin to varying degrees in the nucleus as well. The expression of beta-catenin gene statistically showed the highest level in M5 (n = 15) and the lowest level in M3 (n = 18). No clinical features, such as, age, initial WBC count, therapy response rate, blast cell numbers or cytogenetic risk was found to be correlated with the expression of beta-catenin excepting for CD34+ positive rate (P = 0.004) in AML.

    Conclusion: As a key mediator of Wnt signal transduction way, overexpression of beta-catenin in leukemia cells indicates that it might be aberrantly activated in acute leukemia, accelerated or blastic phase of CML.

    Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 2007;28;8;541-4

  • A microtiter assay for quantifying protein-protein interactions associated with cell-cell adhesion.

    Graham NA, Pope MD, Rimchala T, Huang BK and Asthagiri AR

    Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA.

    Cell-cell adhesions are a hallmark of epithelial tissues, and the disruption of these contacts plays a critical role in both the early and late stages of oncogenesis. The interaction between the transmembrane protein E-cadherin and the intracellular protein beta-catenin plays a crucial role in the formation and maintenance of epithelial cell-cell contacts and is known to be downregulated in many cancers. The authors have developed a protein complex enzyme-linked immunosorbent assay (ELISA) that can quantify the amount of beta-catenin bound to E-cadherin in unpurified whole-cell lysates with a Z' factor of 0.74. The quantitative nature of the E-cadherin:beta-catenin ELISA represents a dramatic improvement over the low-throughput assays currently used to characterize endogenous E-cadherin:beta-catenin complexes. In addition, the protein complex ELISA format is compatible with standard sandwich ELISAs for parallel measurements of total levels of endogenous E-cadherin and beta-catenin. In 2 case studies closely related to cancer cell biology, the authors use the protein complex ELISA and traditional sandwich ELISAs to provide a detailed, quantitative picture of the molecular changes occurring within adherens junctions in vivo. Because the E-cadherin: beta-catenin protein complex plays a crucial role in oncogenesis, this protein complex ELISA may prove to be a valuable quantitative prognostic marker of tumor progression.

    Journal of biomolecular screening 2007;12;5;683-93

  • Regulation of FOXO3a/beta-catenin/GSK-3beta signaling by 3,3'-diindolylmethane contributes to inhibition of cell proliferation and induction of apoptosis in prostate cancer cells.

    Li Y, Wang Z, Kong D, Murthy S, Dou QP, Sheng S, Reddy GP and Sarkar FH

    Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.

    Previous studies from our laboratory have shown anti-proliferative and pro-apoptotic effects of 3,3'-diindolylmethane (DIM) through regulation of Akt and androgen receptor (AR) in prostate cancer cells. However, the mechanism by which DIM regulates Akt and AR signaling pathways has not been fully investigated. It has been known that FOXO3a and glycogen synthase kinase-3beta (GSK-3beta), two targets of activated Akt, interact with beta-catenin, regulating cell proliferation and apoptotic cell death. More importantly, FOXO3a, GSK-3beta, and beta-catenin are all AR coregulators and regulate the activity of AR, mediating the development and progression of prostate cancers. Here, we investigated the molecular effects of B-DIM, a formulated DIM with higher bioavailability, on Akt/FOXO3a/GSK-3beta/beta-catenin/AR signaling in hormone-sensitive LNCaP and hormone-insensitive C4-2B prostate cancer cells. We found that B-DIM significantly inhibited the phosphorylation of Akt and FOXO3a and increased the phosphorylation of beta-catenin, leading to the inhibition of cell growth and induction of apoptosis. We also found that B-DIM significantly inhibited beta-catenin nuclear translocation. By electrophoretic mobility shift and chromatin immunoprecipitation assays, we found that B-DIM inhibited FOXO3a binding to the promoter of AR and promoted FOXO3a binding to the p27(KIP1) promoter, resulting in the alteration of AR and p27(KIP1) expression, the inhibition of cell proliferation, and the induction of apoptosis in both androgen-sensitive and -insensitive prostate cancer cells. These results suggest that B-DIM-induced cell growth inhibition and apoptosis induction are partly mediated through the regulation of Akt/FOXO3a/GSK-3beta/beta-catenin/AR signaling. Therefore, B-DIM could be a promising non-toxic agent for possible treatment of hormone-sensitive but most importantly hormone-refractory prostate cancers.

    Funded by: NCI NIH HHS: 5R01CA108535

    The Journal of biological chemistry 2007;282;29;21542-50

  • Fascin, a novel target of beta-catenin-TCF signaling, is expressed at the invasive front of human colon cancer.

    Vignjevic D, Schoumacher M, Gavert N, Janssen KP, Jih G, Laé M, Louvard D, Ben-Ze'ev A and Robine S

    UMR 144 Centre National de la Recherche Scientifique and Department of Pathology, Institut Curie, 25 rue d'Ulm, 75248 Paris Cedex 05, France. danijela.vignjevic@curie.fr

    Cancer cells become metastatic by acquiring a motile and invasive phenotype. This step requires remodeling of the actin cytoskeleton and the expression of exploratory, sensory organelles known as filopodia. Aberrant beta-catenin-TCF target gene activation plays a major role in colorectal cancer development. We identified fascin1, a key component of filopodia, as a target of beta-catenin-TCF signaling in colorectal cancer cells. Fascin1 mRNA and protein expression were increased in primary cancers in a stage-dependent manner. Fascin1 was exclusively localized at the invasive front of tumors also displaying nuclear beta-catenin. Forced expression of fascin1 in colorectal cancer cells increased their migration and invasion in cell cultures and caused cell dissemination and metastasis in vivo, whereas suppression of fascin1 expression by small interfering RNA reduces cell invasion. Although expression of fascin1 in primary tumors correlated with the presence of metastases, fascin1 was not expressed in metastases. Our studies show that fascin1 expression is tightly regulated during development of colon cancer metastases and is a novel target of beta-catenin-TCF signaling. We propose that transient up-regulation of fascin1 in colorectal cancer promotes the acquisition of migratory and invasive phenotypes that lead to metastasis. Moreover, the expression of fascin1 is down-regulated when tumor cells reach their metastatic destination where migration ceases and proliferation is enhanced. Although metastasis to vital organs is often the cause of mortality, only limited success has been attained in developing effective therapeutics against metastatic disease. We propose that genes involved in cell migration and invasion, such as fascin1, could serve as novel targets for metastasis prevention.

    Cancer research 2007;67;14;6844-53

  • Enteroendocrine precursors differentiate independently of Wnt and form serotonin expressing adenomas in response to active beta-catenin.

    Wang Y, Giel-Moloney M, Rindi G and Leiter AB

    Division of Gastroenterology, GRASP Digestive Disease Center, Tufts-New England Medical Center, Boston, MA 02111, USA.

    Wnt signaling is required for the maintenance of intestinal stem cells and self-renewal of the intestinal epithelium. Intestinal cancers are frequently associated with mutations that activate the Wnt pathway. The role of Wnt signaling on differentiation of lineage-specific precursors in the intestine is not well characterized. Here, we show that specification of enteroendocrine but not Paneth cells occurs independently of Wnt signals by conditional deletion of beta-catenin in immature cells expressing the transcription factor, neurogenin 3. In addition, we determined whether neurogenin 3-expressing cells respond to abnormal Wnt signaling. Activation of the Wnt pathway by conditionally deleting exon 3 of the beta-catenin gene at an early stage of enteroendocrine cell differentiation induced small-intestinal adenomas expressing serotonin, a feature not previously described in other tumors induced by Wnt in mice. In contrast, excision of exon 3 of beta-catenin at a later stage of enteroendocrine differentiation did not produce tumors. These results provide direct evidence that some intestinal lineages are specified independently of the Wnt pathway and may lead to a better understanding of the spectrum of neuroendocrine differentiation frequently seen in human gastrointestinal cancer.

    Funded by: NIDDK NIH HHS: DK43673, DK52870, DK67166, P30 DK034928, P30-DK34928, R01 DK043673, R01 DK067166, T32 DK007542, T32-DK007542

    Proceedings of the National Academy of Sciences of the United States of America 2007;104;27;11328-33

  • A genetic association analysis of cognitive ability and cognitive ageing using 325 markers for 109 genes associated with oxidative stress or cognition.

    Harris SE, Fox H, Wright AF, Hayward C, Starr JM, Whalley LJ and Deary IJ

    Department of Psychology, University of Edinburgh, Edinburgh, UK. Sarah.Harris@hgu.mrc.ac.uk <Sarah.Harris@hgu.mrc.ac.uk&gt;

    Background: Non-pathological cognitive ageing is a distressing condition affecting an increasing number of people in our 'ageing society'. Oxidative stress is hypothesised to have a major role in cellular ageing, including brain ageing.

    Results: Associations between cognitive ageing and 325 single nucleotide polymorphisms (SNPs), located in 109 genes implicated in oxidative stress and/or cognition, were examined in a unique cohort of relatively healthy older people, on whom we have cognitive ability scores at ages 11 and 79 years (LBC1921). SNPs showing a significant positive association were then genotyped in a second cohort for whom we have cognitive ability scores at the ages of 11 and 64 years (ABC1936). An intronic SNP in the APP gene (rs2830102) was significantly associated with cognitive ageing in both LBC1921 and a combined LBC1921/ABC1936 analysis (p < 0.01), but not in ABC1936 alone.

    Conclusion: This study suggests a possible role for APP in normal cognitive ageing, in addition to its role in Alzheimer's disease.

    Funded by: Medical Research Council: MC_U127561128

    BMC genetics 2007;8;43

  • Beta-catenin expression enhances IL-7 receptor signaling in thymocytes during positive selection.

    Yu Q, Xu M and Sen JM

    Lymphocyte Development Unit, Laboratory of Immunology, National Institute on Aging, National Institutes of Health, Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.

    Differentiation of CD4+CD8+ double-positive thymocytes into CD8+ single-positive (SP) thymocytes is regulated by TCR and cytokine receptor signals. Previously, we have shown that expression of stabilized beta-catenin, the major transcriptional cofactor of T cell factor, results in increase in both CD4SP and CD8SP thymocytes with a preferential effect on CD8SP thymocytes. In this report, using mice expressing stabilized beta-catenin and mice with T cell specific deletion of beta-catenin, we show that beta-catenin expression augments IL-7Ralpha-chain expression and down-regulates suppressor of cytokine signaling-1 expression in thymocytes undergoing positive selection. Consequently, beta-catenin expression augments IL-7R signaling in thymocytes during positive selection and promotes the development of CD8SP thymocytes.

    Funded by: Intramural NIH HHS: Z01 AG000768-04

    Journal of immunology (Baltimore, Md. : 1950) 2007;179;1;126-31

  • Correlation of beta-catenin localization with cyclooxygenase-2 expression and CpG island methylator phenotype (CIMP) in colorectal cancer.

    Kawasaki T, Nosho K, Ohnishi M, Suemoto Y, Kirkner GJ, Dehari R, Meyerhardt JA, Fuchs CS and Ogino S

    Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.

    The WNT/beta-catenin (CTNNB1) pathway is commonly activated in the carcinogenic process. Cross-talks between the WNT and cyclooxygenase-2 (COX-2 or PTGS2)/prostaglandin pathways have been suggested. The relationship between beta-catenin activation and microsatellite instability (MSI) in colorectal cancer has been controversial. The CpG island methylator phenotype (CIMP or CIMP-high) with widespread promoter methylation is a distinct epigenetic phenotype in colorectal cancer, which is associated with MSI-high. However, no study has examined the relationship between beta-catenin activation and CIMP status. Using 832 population-based colorectal cancer specimens, we assessed beta-catenin localization by immunohistochemistry. We quantified DNA methylation in eight CIMP-specific promoters [CACNA1G, CDKN2A(p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1] by real-time polymerase chain reaction (MethyLight). MSI-high, CIMP-high, and BRAF mutation were associated inversely with cytoplasmic and nuclear beta-catenin expressions (i.e., beta-catenin activation) and associated positively with membrane expression. The inverse relation between beta-catenin activation and CIMP was independent of MSI. COX-2 overexpression correlated with cytoplasmic beta-catenin expression (even after tumors were stratified by CIMP status), but did not correlate significantly with nuclear or membrane expression. In conclusion, beta-catenin activation is inversely associated with CIMP-high independent of MSI status. Cytoplasmic beta-catenin is associated with COX-2 overexpression, supporting the role of cytoplasmic beta-catenin in stabilizing PTGS2 (COX-2) mRNA.

    Funded by: NCI NIH HHS: P01 CA055075, P01 CA087969, P01 CA55075, P01 CA87969

    Neoplasia (New York, N.Y.) 2007;9;7;569-77

  • Expression of E-cadherin, beta-catenin and p120ctn in the pulmonary sclerosing hemangioma.

    Dai SD, Zhang XW, Qi FJ, Xu HT and Wang EH

    Department of Pathology, College of Basic Medical Sciences, China Medical University, Shenyang 110001, China.

    Background: The major two types of cells in pulmonary sclerosing hemangiomas (PSH) may be not equally maturity, but this viewpoint needs more evidences.

    Aim: To determine E-cadherin, beta-catenin and p120(ctn) expression phenotype in cuboidal and polygonal cells, which are the two major cell types in pulmonary sclerosing hemangiomas.

    Methods: Specimens were obtained from 25 patients with PSH and 8 patients with pulmonary inflammatory pseudotumors. The expression levels of E-cadherin, beta-catenin and p120(ctn) were detected using a streptavidin peroxidase (SP) immunohistochemical method.

    Results: E-cadherin, beta-catenin and p120(ctn) were expressed strongly on the cuboidal cell membranes, while beta-catenin was also expressed the cuboid cytoplams in 25 PSH patients. However, in the polygonal cell membranes, the expression levels of these molecules were decreased, and mainly cytoplamic. Specifically, E-cadherin, beta-catenin and p120(ctn) were expressed in both the cytoplasm and on the cell membranes in the intracavitary lining cells of the hemorrhagic regions. The expression phenotype in proliferating type II pneumocytes in the eight pulmonary inflammatory pseudotumors was similar to that in the cuboidal cells in PSH patients.

    Conclusion: The cuboidal cells, resembling inflammatory proliferative type II pneumocytes, display several characteristics of epithelial cells, including normal expression of E-cadherin and catenin. Comparatively, polygonal cells are not as mature as cuboidal cells and lack of expression of E-cadherin and catenin.

    Lung cancer (Amsterdam, Netherlands) 2007;57;1;54-9