Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The p51/p63 gene is a homologue of p53, the product of which acts as a transcriptional activator by binding to p53-responsive elements in the promoter regions of several p53 downstream genes. Recently, we identified four distinct mutations in the p51/p63 gene after screening >200 human tumors and cell lines. Because all of the detected p51/p63 mutations were missense mutations, the pathogenic effect of these mutations is difficult to determine without performing a functional analysis. In this study, we examined the transcriptional activity of tumor-derived p51/p63 missense mutations using a yeast-based assay and compared the data with that of artificial p51/p63 missense mutations at residues corresponding to the positions and substituted residues of p53 mutation "hotspots." Although most of the p51/p63 missense mutations at the p53 hotspot residues were unable to transactivate the promoters used in this study, the tumor-derived p51/p63 missense mutations retained their ability to transactivate the MDM2 and/or the BAX promoter but not the p21/WAF1 promoter. These results suggest that the p51/p63 mutation might be involved in an unknown tumor suppression pathway distinct from that of p53.
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PMID:Effects of p51/p63 missense mutations on transcriptional activities of p53 downstream gene promoters. 1060 33

The purpose of our study was to determine the expression of the pro-apoptotic BAX protein in relation to the mutational status of BAX and p53 (as transcriptional activator of the BAX gene) in benign and malignant thyroid tissue. In 47 patients with thyroid tumours (14 follicular and 3 papillary carcinomas, 14 adenomas and 16 goitres), the DNA was screened for mutations of BAX (exon 1-6) and p53 (exon 5-8) by single-strand conformation polymorphism polymerase chain reaction (SSCP-PCR). Furthermore, the protein expression of BAX, p53 and p21 (which is also increased transcriptionally by p53) was investigated by immunohistochemistry. Surprisingly, we observed elevated BAX levels in patients with thyroid carcinomas compared with patients with adenomas (unpaired t-test: p<0.05) or with goitres (p<0.02). This is in clear contrast to other carcinomas where BAX is frequently inactivated which correlates to a poor prognosis (Sturm et al. J. Clin. Oncol. 1999;17:1364-74.). There were no significant differences of the BAX levels between goitres or the adenomas. In the SSCP-PCR analysis, no BAX mutations were detectable. P53 mutation analysis by SSCP-PCR did not reveal any functional p53 mutations in the patients with carcinomas, adenomas or goitres. Nevertheless, patients with carcinomas showed an overexpression (preferentially cytoplasmic) of p53 protein compared with patients with benign tumours (p<0.05). The absence of p53 mutations suggests that the overexpressed p53 is wild type. This is in line with the expression profile of BAX and p21, which showed a higher protein expression in these p53 positive tumours (p<0.05 in the carcinomas compared with the non-malignant lesions). Consequently, the overexpressed p53 might be a correlate for dysregulation without loss of function. This, in turn, might be a reason for the good outcome of some patients with thyroid cancer.
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PMID:Bax expression in benign and malignant thyroid tumours: dysregulation of wild-type P53 is associated with a high Bax and P21 expression in thyroid carcinoma. 1135 Dec 99

Doxorubicin (DOX), an anticancer drug, causes a dose-dependent cardiotoxicity. Some evidence suggests that female children have an increased risk for DOX-mediated cardiac damage. To determine whether the iron chelator dexrazoxane (DXR) could reduce DOX-induced cardiotoxicity in the young, we injected day 10 neonate female and male rat pups with a single dose of saline or DOX, DXR, or DXR + DOX (20:1). We followed body weight gain with growth, measured cardiac hypertrophy after a 2-wk swim exercise program, markers of apoptosis (Bcl-2, BAX, BNIP1, caspase 3 activation), oxidative stress (heme oxygenase 1, protein carbonyl levels), the chaperone protein clusterin, and the transcriptional activator early growth response gene-1 (Egr-1) in hearts of nonexercised and exercised rats on neonate day 38. All DOX-alone and DXR + DOX-treated rats showed decreased weight gain, with female rats affected earlier than male rats. DXR-alone, DOX-alone, and DXR + DOX-treated rats had an increased heart weight-to-body weight (heart wt/body wt) ratio after the exercise program with female rats showing the largest increase in heart wt/body wt. Drug-treated females also showed increased cardiac apoptosis, as measured by the increased expression of the proapoptotic proteins BAX and BNIP1 and the appearance of caspase 3 activation products, and oxidative stress, as measured by increased heme oxygenase 1 expression, and reduced Egr-1 and clusterin expression when compared with the similarly treated male rats. We conclude that DXR preinjection did not reduce DOX-induced noncardiac and cardiac damage and that young female rats were more susceptible to DXR and DOX toxicities than age-matched male rats.
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PMID:Dexrazoxane does not protect against doxorubicin-induced damage in young rats. 1271 34

The SALL2 gene product and transcription factor p150 were first identified in a search for tumor suppressors targeted for inactivation by the oncogenic mouse polyoma virus. SALL2 has also been identified as a cellular quiescence factor, essential for cells to enter and remain in a state of growth arrest under conditions of serum deprivation. p150 is a transcriptional activator of p21(Cip1/Waf1) and BAX, sharing important growth arrest and proapoptotic properties with p53. It also acts as a repressor of c-myc. Restoration of SALL2 expression in cells derived from a human ovarian carcinoma (OVCA) suppresses growth of the cells in immunodeficient mice. Here we examine the pattern of p150 expression in the normal human ovary, in OVCA-derived cell lines and in primary ovarian carcinomas. Immunohistochemical staining showed that p150 is highly expressed in surface epithelial cells of the normal human ovary. Expression is exclusively from the P2 promoter governing the E1A splice variant of p150. The P2 promoter is CpG-rich and susceptible to methylation silencing. p150 expression was restored in OVCA cell lines following growth in the presence of 5-azacytidine. In a survey of 210 cases of OVCA, roughly 90% across major and minor histological types failed to show expression of the protein. Immunological and biochemical approaches were used to show hypermethylation of the SALL2 P2 promoter in OVCA-derived cell lines and in a majority of primary tumors. These results bring together molecular biological and clinical evidence in support of a role of SALL2 as a suppressor of ovarian cancers.
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PMID:Promoter methylation of the SALL2 tumor suppressor gene in ovarian cancers. 2327 47

Camalexin, the phytoalexin produced in the model plant Arabidopsis thaliana, possesses antiproliferative and cancer chemopreventive effects. We have demonstrated that the cytostatic/cytotoxic effects of camalexin on several prostate cancer (PCa) cells are due to oxidative stress. Lysosomes are vulnerable organelles to Reactive Oxygen Species (ROS)-induced injuries, with the potential to initiate and or facilitate apoptosis subsequent to release of proteases such as cathepsin D (CD) into the cytosol. We therefore hypothesized that camalexin reduces cell viability in PCa cells via alterations in expression and activity of CD. Cell viability was evaluated by MTS cell proliferation assay in LNCaP and ARCaP Epithelial (E) cells, and their respective aggressive sublines C4-2 and ARCaP Mesenchymal (M) cells, whereby the more aggressive PCa cells (C4-2 and ARCaPM) displayed greater sensitivity to camalexin treatments than the lesser aggressive cells (LNCaP and ARCaPE). Immunocytochemical analysis revealed CD relocalization from the lysosome to the cytosol subsequent to camalexin treatments, which was associated with increased protein expression of mature CD; p53, a transcriptional activator of CD; BAX, a downstream effector of CD, and cleaved PARP, a hallmark for apoptosis. Therefore, camalexin reduces cell viability via CD and may present as a novel therapeutic agent for treatment of metastatic prostate cancer cells.
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PMID:Camalexin-induced apoptosis in prostate cancer cells involves alterations of expression and activity of lysosomal protease cathepsin D. 2469 44