Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dysfunction of the cadherin-catenin complex, a key component of adherens junctions, is thought to confer invasive potential to cells. The aim of this study is to examine the expression and function of the E-cadherin/catenin complex in gastric carcinoma cell lines. Expression of E-cadherin, alpha, beta and gamma-catenin and p120ctn, and of the adenomatous polyposis coli protein (APC), together with function of the cadherin-catenin complex was examined in a panel of gastric carcinoma cell lines, using immunocytochemistry, Western blotting and a cell-cell aggregation assay. Protein interactions were examined by sequential immunoprecipitation and immunoblotting with antibodies to E-cadherin, alpha, beta and gamma-catenin, p120ctn and APC. Abnormalities of E-cadherin, alpha- and beta-catenin expression, were associated with disturbance of E-cadherin-catenin complex composition, loss of membranous localization and loss of calcium-dependent aggregation in six gastric carcinoma cell lines. APC protein expression and interaction with beta-catenin was preserved in five cell lines. We demonstrate frequent abnormalities of expression and function of E-cadherin and catenins, and associated disturbance of E-cadherin-mediated intercellular adhesion in gastric carcinoma cell lines. These findings support the tumour suppressor role of the E-cadherin and its contribution to the development and progression of the neoplastic phenotype in gastric carcinoma.
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PMID:Abnormal expression and function of the E-cadherin-catenin complex in gastric carcinoma cell lines. 1040 33

p73 has been identified as a gene that encodes a protein with significant identity with the tumour suppressor p53. The main structural difference between p73 and p53 is the additional C-terminal region of p73. Six isoforms of p73 with differing C-terminal structures, alpha, beta, gamma, delta, epsilon and xi, have been reported. These variants differ in transcriptional activity on p53-responsive promoters. Here we report a possible mechanism of transcriptional activation by p73 splicing variants. C-terminal deletion mutants of p73 alpha showed a significantly higher level of transcriptional activity than wild-type p73 alpha, suggesting that the C-terminal structure of p73 alpha functions to repress the transcriptional activity of p73 alpha. The results of immunoprecipitation assays and two-hybrid assays in mammalian cells showed that the p73 variants interacted with each other, but not with p53. The transcriptional activity of p73 beta was reduced by co-expression with either p73 alpha or p73 epsilon, which bears an identical C-terminal structure to p73 alpha. Co-expression of the C-terminal portion of p73 alpha or p73 epsilon with p73 beta also resulted in reduced transcriptional activity. Moreover, we observed that the level of endogenous p21 protein induced by p73 beta was decreased by co-expression of full-length p73 epsilon or the C-terminal region of p73 alpha or p73 epsilon. These observations suggest that p73-mediated gene expression is regulated by the interactions of p73 splicing variants in the cell.
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PMID:Transcriptional activities of p73 splicing variants are regulated by inter-variant association. 1138 95

Retinoic acid (RA) and its natural and synthetic derivatives (retinoids) are important dietary factors which regulate cellular differentiation and growth, so that they are thought to be particularly effective at preventing the development of several tumours. They play this role as ligands of the RAR and RXR nuclear retinoic acid receptors, including the RA receptor isoforms alpha, beta, and gamma. These ligand-activated nuclear receptors induce the transcription of target genes by binding to RA-responsive elements in the promoter regions. Among these target genes, the RARbeta gene is of great interest, being able to encode a potential tumour suppressor. It should be emphasized that most breast carcinomas and breast cancer cell lines show loss or down-regulation of RARbeta receptor expression, whereas RARalpha and gamma, as well as retinoid X receptors, appear to be variably expressed in both normal and tumour cells. It is also interesting to note that basal and RA-induced RARbeta mRNA levels tend to increase with senescence of normal cells. This information provides further support for the hypothesis that genetic events involved in cellular senescence may also play a significant role in tumour suppression in humans. The aim of this review is to clarify whether expression of RARbeta could be modulated by chemopreventive intervention and may therefore serve as an intermediate biomarker in chemoprevention trials for some cancers.
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PMID:Nuclear retinoic acid receptor beta as a tool in chemoprevention trials. 1716 22