Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:B0FTZ7 (catenin)
 18,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Loss of membranous expression of beta-catenin is associated with tumor progression in cutaneous melanoma and rarely caused by exon 3 mutations. 1195 Sep 21

Neuroendocrine tumors (NETs) of the gastrointestinal tract comprise a heterogeneous group of neoplasms arising from the diffuse neuroendocrine system. These tumors strongly differ from each other on the basis of different pathogenetic, clinical, functional, histological, and prognostic patterns. Previous studies have shown that abnormal and reduced expression of the E-cadherin/catenin complex in several human cancers is associated with tumor dedifferentiation, advanced clinical stages, and poor survival rate. We assessed correlations between the expression of E-cadherin and catenins, Ki-67, and the following clinicopathological factors: age, embryological site of origin, size, histological growth pattern, the depth of penetration into the intestinal wall, and the presence of metastasis. In this study, reduction of membranous E-cadherin expression to a variable degree was detected in more than two-thirds (42 of 51) of gastrointestinal NETs (19 foregut, 8 midgut, and 24 hindgut) belonging to the complete neuroendocrine neoplastic spectrum [18 well-differentiated NETs, 22 well-differentiated neuroendocrine carcinomas (NECs), and 11 poorly differentiated NECs]. The reduction of E-cadherin expression was concomitant with the reduction of alpha-catenin (44 of 51) and beta-catenin (35 of 51) expression. Our immunohistochemical analysis demonstrated significant differences of percentage of membranous positive cells of E-cadherin, alpha-catenin, or beta-catenin between normal tissues and well-differentiated NETs (P=0.0038, P=0.004, and P=0.0329, respectively), well-differentiated NECs (P<0.001, P<0.001, and P<0.001, respectively) and poorly differentiated NECs (P=0.0002, P<0.0002, and P=0.0002, respectively). Among the gastrointestinal NETs, there were significantly more positive cells of E-cadherin, alpha-catenin, or beta-catenin in well-differentiated NETs than well-differentiated NECs (P=0.0006, P=0.0065, and P=0.0001, respectively) or poorly differentiated NECs (P=0.0053, P=0.0041, and P<0.001, respectively). MIB-1 labeling index generally showed a low proliferative activity in well-differentiated NETs (0.49+/-0.37) and well-differentiated NECs (0.662+/-0.66). A high proliferation rate was observed in poorly differentiated NECs (41.518+/-16.59). MIB-1 labeling index was significantly higher in poorly differentiated NECs than well-differentiated NETs and well-differentiated NECs (P<0.0001 and P<0.0001, respectively). E-cadherin, alpha-catenin, and beta-catenin expression were correlated significantly with transmural tumor invasion (P<0.0001, P=0.0001, and P<0.0001, respectively) and with size (P=0.0013, P=0.0001, and P<0.0001, respectively). These results indicate that the alteration in the E-cadherin/catenin expression may be involved in the growth and progression of gastrointestinal NETs.
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PMID:Alterations of E-cadherin, alpha-catenin and beta-catenin expression in neuroendocrine tumors of the gastrointestinal tract. 1196 44

Src has been implicated in the development and progression of human colon cancer. Because the capacity for tumor cells to dissociate from the primary tumor is a critical step in the development of metastases, the effect of a naturally occurring, activated Src-531 on intercellular adhesion was examined. Homotypic adhesion was assessed using dissociation assays on Src-transformed rat fibroblasts and human colon cancer cell lines. The data indicate that both rodent and human cells expressing the mutant Src protein display up to 7-fold less homotypic adhesion than do wild-type cells (P < 0.01). Experiments demonstrated that cadherin was phosphorylated in cells transfected with activated Src and that cadherin/catenin complexes were disrupted as a result. Experiments using dominant negative (DN) Src or an Src-specific inhibitor (PD 180970), demonstrated that adhesion was restored when Src activity was inhibited in Src-531 transfectants, confirming that Src is a causal factor in the decreased homotypic adhesion observed. In addition, DN Ras, DN focal adhesion kinase (FAK), but not Stat3beta, restored intercellular adhesion, which suggested that Ras and FAK may be downstream effectors of Src-mediated homotypic adhesion. Collectively, these data support a role for Src, Ras, and FAK in the regulation of intercellular adhesion, which may in turn regulate metastatic potential of human colon cancer cells.
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PMID:Increased Src activity disrupts cadherin/catenin-mediated homotypic adhesion in human colon cancer and transformed rodent cells. 1198 Jun 66

Abnormal expression of the alphaE-catenin protein, a component of the E-cadherin/catenin cell adhesion complex, is frequently observed in human cancer cells. An inverse correlation between alphaE-catenin expression and tumor malignancy can be of prognostic value. Mutations of the alphaE-catenin gene, CTNNA1, were described in several human cancer cell lines and were found to result in aberrant cell adhesion. We have developed a polymerase chain reaction/single-strand conformation polymorphism-based method for mutation analysis of this gene in human tumor DNA. This approach enabled us to identify several polymorphisms in a set of desmoid tumors, demonstrating that this method is suitable for alphaE-catenin mutational analysis. On the basis of our genomic characterization data, we found that the previously reported alternative splicing of the alphaE-catenin gene actually generates a frame-shift, resulting in a truncated alphaE-catenin protein. This finding is unlike the other alpha-catenin family members alphaN-catenin and vinculin, which show in-frame alternative inserts. Furthermore, real-time quantitative reverse transcriptase-PCR analysis did not reveal relevant expression levels of this alternatively spliced alphaE-catenin variant neither in any human tissue or cell line tested, nor at any mouse developmental stage tested. Thus, contrary to previous notions, alternative splicing with in-frame insertion nearby the C-terminal end of the protein is not a general feature for all members of the alpha-catenin/vinculin family.
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PMID:The human alphaE-catenin gene CTNNA1: mutational analysis and rare occurrence of a truncated splice variant. 1199 91

Among the hallmarks of cancer are defective cell-cell and cell-matrix adhesion. Alterations in cadherin-catenin complexes likely have a major contributing role in cell-adhesion defects in carcinomas arising in many different tissues. E-cadherin, the prototypic member of the cadherin transmembrane protein family, regulates cell adhesion by interacting with E-cadherin molecules on opposing cell surfaces. E-cadherin's function in cell adhesion is also critically dependent on its ability to interact through its cytoplasmic domain with catenin proteins. A diverse collection of defects alter cadherin-catenin function in cancer cells, including loss-of-function mutations and defects in the expression of E-cadherin and certain catenins, such as alpha-catenin. Although there is much evidence that beta-catenin is deregulated in cancer as a result of inactivating mutations in the APC and AXIN tumor-suppressor proteins and gain-of-function mutations in beta-catenin itself, the principal consequences of beta-catenin deregulation in cancer appear to be largely distinct from the effects attributable to inactivation of E-cadherin or alpha-catenin. In this review, we highlight some of the specific genetic and epigenetic defects responsible for altered cadherin and catenin function in cancer, as well as potential contributions of cadherin-catenin alterations to the cancer process.
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PMID:Cadherin and catenin alterations in human cancer. 1200 86

Inflammatory breast carcinoma (IBC) is characterized by florid tumor emboli within lymphovascular spaces termed lymphovascular invasion (LVI). Using a human-scid model of IBC (MARY-X), we have demonstrated using retrovirally-mediated dominant-negative E-cadherin mutant approaches (H-2K(d)-E-cad), that the tumor cell embolus (IBC spheroid) forms on the basis of an intact and overexpressed E-cadherin/alpha, beta-catenin axis which mediates tumor cell-tumor cell adhesion analogous to the embryonic blastocyst and accounts for the compactness of the embolus. The tumor cell embolus (IBC spheroid), in contrast, fails to bind the surrounding vascular endothelial cells both in vitro and in vivo because of markedly decreased sialyl-Lewis X/A carbohydrate ligand-binding epitopes on its overexpressed MUC1 which are necessary for binding endothelial cell E-selectin. This tumor cell-endothelial cell aversion further contributes to the compactness of the IBC spheroid and its passivity in metastasis dissemination. This passivity is manifested by a dramatic increase in metastatic pulmonary emboli following palpation of the primary tumor. In assessing this passivity of metastatic dissemination, we compared the effects of palpation on MARY-X with the effects of palpation on a derived dominant-negative E-cadherin mutant (H-2K(d)-E-cad), as well as other well known human tumoral xenografts exhibiting no (MCF-7, T47D), low (MDA-MB-231, MDA-MB-468) or high (C8161, M24(met)) levels of spontaneous metastasis but no LVI. Palpation of each xenograft similarly increased intratumoral pressure by 200% (10-->30 mmHg) but dramatically increased the numbers and sizes of pulmonary metastases 10-100-fold (P<0.001) only in MARY-X. The mechanism of this effect was through an immediate post-palpation release of circulating tumor emboli detected 2-3 min after palpation (P<0.01) by human cytokeratin 19 RT-PCR of extracted RNA from 300 microl of murine blood. Although circulating human tumor cell-derived growth factors (IGF-I, IGF-II, TGF-alpha and TGF-beta) and angiogenic factors (VEGF and bFGF) were detected by ELISA in murine serum of MARY-X, palpation did not further increase the circulating levels of these factors (P>0.1). Our findings support the cooperative role of E-cadherin and sialyl-Lewis X/A-deficient MUC1 in the passive dissemination of tumor emboli in IBC.
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PMID:Cooperative role of E-cadherin and sialyl-Lewis X/A-deficient MUC1 in the passive dissemination of tumor emboli in inflammatory breast carcinoma. 1203 65

The cadherin-catenin complex has been recognized as an important factor associated with tumor metastasis. However, the clinical significance of the expression of adhesion molecules in lymph nodes with metastasis remains unclear. The aim of this study was to investigate the clinical significance of the re-expression of the cadherin-catenin complex in metastatic lymph nodes in patients with advanced gastric cancer. Immunohistochemical expression of E-cadherin, alpha- and beta-catenin were analyzed in 96 primary gastric cancers with serosal invasion and in 79 lymph nodes with metastasis. The expression levels of these adhesion molecules in primary tumors and lymph nodes with metastasis were compared. Ninety-four out of 96 primary tumors (98%) showed reduced expression of adhesion molecules. Out of 79 cases with lymph node metastasis, increased expression of one or more adhesion molecules in metastatic foci as compared with primary tumors was detected in 52 cases (66%). Re-expression of adhesion molecules in metastatic lymph nodes was detected in a more advanced stage. The overall 5-year survival rate of the 52 patients who had lymph nodes with metastasis with re-expression of adhesion molecules (8%) was significantly poorer than that of the 27 who had lymph nodes with metastasis without re-expression of adhesion molecules (33%, P = 0.0012). The re-expression of the cadherin-catenin complex in lymph nodes with metastasis may play an important role in the growth of cancer cells in metastatic foci. A comparison of the expression patterns of adhesion molecules between the primary tumor and metastatic lymph nodes may provide new prognostic information for patients with advanced gastric cancer.
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PMID:Re-expression of the cadherin-catenin complex in lymph nodes with metastasis in advanced gastric cancer: the relationship with patient survival. 1207 32

E-cadherin and its associated cytoplasmic proteins including alpha-, beta-, and gamma-catenin play a pivotal role in the maintenance of normal tissue architecture and the suppression of cancer invasion. The purpose of this study was to evaluate the expression of E-cadherin and alpha-, beta-, and gamma-catenin in a larger sample of early gastric cancer, and to examine the relation between these expressions and various clinicopathologic variables. The expression of E-cadherin and alpha-, beta-, and gamma-catenin was investigated using immunohistochemical technique with formalin-fixed, paraffin-embedded tissue specimens obtained from 108 patients who underwent surgery for early gastric cancer. In the gastric mucosa of noncancerous areas, epithelial cells showed equally strong membranous expression of E-cadherin and alpha-, beta-, and gamma-catenin proteins at the cell-cell boundaries. Reduced expression of E-cadherin and alpha-, beta-, and gamma-catenin was demonstrated in 43.5%, 39.8%, 42.6%, and 50% of cancer tissues, respectively. Whereas 34 tumors (31.5%) displayed preserved expression of all four E-cadherin-catenin complex components, 21 tumors (19.4%) displayed reduced expression of all components of this complex. Reduced expression of E-cadherin and alpha- and gamma-catenin occurred more frequently in diffuse than in intestinal types of cancer, and decreased expression of E-cadherin and alpha-, beta-, and gamma-catenin correlated with poor differentiation. The expression of E-cadherin and beta- and gamma-catenin did not correlate with the patient's age, gender, tumor size, location, macroscopic type, depth of invasion, or lymph node metastasis. Only reduced expression of alpha-catenin correlated with lymph node metastasis. Reduced expression of all four E-cadherin-catenin complex components correlated with poorly differentiated and diffuse-type cancers, but not with the patient's age, gender, tumor size, location, macroscopic type, depth of invasion, or lymph node metastasis. These results suggest that dysfunction of the E-cadherin-catenin complex occurs in an early stage of carcinogenesis, playing a crucial role in disruption of tissue architecture and loss of differentiation in early gastric cancer.
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PMID:Expression of e-cadherin and catenins in early gastric cancer. 1208 Feb 24

Two effects of the citrus methoxyflavone tangeretin on cell-cell interactions are biologically relevant. Firstly, tangeretin upregulates the function of the E-cadherin/catenin complex in human MCF-7/6 breast carcinoma cells. This leads to firm cell-cell adhesion and inhibition of invasion in vitro. Secondly, tangeretin downregulates the interleukin-2 receptor on T-lymphocytes and natural killer cells. This leads to a decrease in the cytotoxic competence of these immunocytes against cancer cells. The second effect can become important when high doses of tangeretin are combined with adjuvant tamoxifen treatment for breast cancer. Experiments with nude mice bearing MCF-7/6 tumors showed that tangeretin given orally at high doses, abrogated the therapeutic suppression of tumor growth exerted by tamoxifen. No evidence for a tumor promoting effect of tangeretin by itself was found in these experiments. Tangeretin may be an interesting molecule for application in cases where immunosuppression could be clinically beneficial.
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PMID:The citrus methoxyflavone tangeretin affects human cell-cell interactions. 1208 57

B -Catenin is closely associated with carcinoma invasion/metastasis and poor survival. Recent studies have demonstrated that abnormal expression of B -catenin, especially its nuclear accumulation, also plays an important role in wingless/Wnt signaling pathway. In this study, we evaluated immunohistochemically the nuclear localization of B -catenin in a total of 93 human-endocrine-related tumors including 1 medullary carcinoma (thyroid gland), 12 parathyroid tumors, 22 carcinoid tumors (digestive tract and liver), 7 islet cell tumors, 26 adrenocortical tumors, 13 neuroblastoma (adrenal gland), and 12 pheochromocytoma (adrenal gland), and also studied genetic alterations of the B -catenin gene. Nuclear accumulation of B -catenin was frequently detected in 8 of 22 (36%) carcinoid tumors and 2 of 7 (29%) islet cell tumors. No genetic alteration in exon 3 of the B -catenin gene encoding serine/threonine rich domain, which was phosphorylated by GSK-3 B, was detected in any groups of the endocrine tumors. However, nuclear accumulation of B -catenin in carcinoid tumors was significantly correlated with the proliferative marker Ki-67 (MIB-1) labeling index (p <0.001). Our findings suggest that nuclear transfer and accumulation of the B -catenin may contribute in the tumorigenesis of carcinoid tumor as an oncoprotein.
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PMID:Nuclear Accumulation of B-Catenin in Human Endocrine Tumors: Association with Ki-67 (MIB-1) Proliferative Activity. 1211 96


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