Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genetic polymorphisms of the carcinogen-metabolizing enzymes cytochrome P450 (CYP), glutathione S-transferase (GST) M1 and N-acetyltransferase (NAT2) as well as p53 polymorphisms have been studied experimentally as susceptibility markers for hepatocellular carcinoma development in hepatocellular carcinoma cell lines and in mouse hepatocellular carcinomas. In addition, these susceptibility markers have been studied in hepatocellular carcinoma patients, in the context of coexisting alcohol consumption, smoking and/or HBV infection. To date, there is no clear evidence that susceptibility markers have an overall impact on hepatocarcinogenesis, but in subgroups of individuals, such as smokers, susceptibility markers are emerging indicators for hepatocellular carcinoma risk definition.
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PMID:Hepatocellular carcinoma: susceptibility markers. 1122 Jun 63

Experimental studies of complete mammalian genes and other genetic domains are impeded by the difficulty of introducing large DNA molecules into cells in culture. Previously we have shown that GST-Z2, a protein that contains three zinc fingers and a proline-rich multimerization domain from the polydactyl zinc finger protein RIP60 fused to glutathione S-transferase (GST), mediates DNA binding and looping in vitro. Atomic force microscopy showed that GST-Z2 is able to condense 130-150 kb bacterial artificial chromosomes (BACs) into protein-DNA complexes containing multiple DNA loops. Condensation of the DNA loops onto the Z2 protein-BAC DNA core complexes with cationic lipid resulted in particles that were readily transferred into multiple cell types in culture. Transfer of total genomic linear DNA containing amplified DHFR genes into DHFR(-) cells by GST-Z2 resulted in a 10-fold higher transformation rate than calcium phosphate co-precipitation. Chinese hamster ovarian cells transfected with a BAC containing the human TP53 gene locus expressed p53, showing native promoter elements are active after GST-Z2-mediated gene transfer. Because DNA condensation by GST-Z2 does not require the introduction of specific recognition sequences into the DNA substrate, condensation by the Z2 domain of RIP60 may be used in conjunction with a variety of other agents to provide a flexible and efficient non-viral platform for the delivery of large genes into mammalian cells.
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PMID:Condensation by DNA looping facilitates transfer of large DNA molecules into mammalian cells. 1132 83

In the present study we present evidence for the critical role of Sp1 in the mechanism of transactivation of the human cell cycle inhibitor p21(WAF1/Cip1) (p21) gene promoter by the tumor suppressor p53 protein. We found that the distal p53-binding site of the p21 promoter acts as an enhancer on the homologous or heterologous promoters in hepatoma HepG2 cells. In transfection experiments, p53 transactivated the p21 promoter in HaCaT cells that express Sp1 but have a mutated p53 form. In contrast, p53 could not transactivate the p21 promoter in the Drosophila embryo-derived Schneider's SL2 cells that lack endogenous Sp1 or related factors. Cotransfection of SL2 cells with p53 and Sp1 resulted in a synergistic transactivation of the p21 promoter. Synergistic transactivation was greatly decreased in SL2 cells and HaCaT cells by mutations in either the p53-binding site or in the -82/-77 Sp1-binding site indicating functional cooperation between Sp1 and p53 in the transactivation of the p21 promoter. Synergistic transactivation was also decreased by mutations in the transactivation domain of p53. Physical interactions between Sp1 and p53 proteins were established by glutathione S-transferase pull-down and coimmunoprecipitation assays. By using deletion mutants we found that the DNA binding domain of Sp1 is required for its physical interaction with p53. In conclusion, Sp1 must play a critical role in regulating important biological processes controlled by p53 via p21 gene activation such as DNA repair, cell growth, differentiation, and apoptosis.
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PMID:Sp1 plays a critical role in the transcriptional activation of the human cyclin-dependent kinase inhibitor p21(WAF1/Cip1) gene by the p53 tumor suppressor protein. 1138 95

Upon exposure of cells to hydrogen peroxide (H(2)O(2)) phosphorylation of p53 was rapidly induced in human fibroblast GM00637, and this phosphorylation occurred on serine 9, serine 15, serine 20, but not on serine 392. In addition, H(2)O(2)-induced phosphorylation of p53 was followed by induction of p21, suggesting functional activation of p53. Induction of phosphorylation of p53 on multiple serine residues by H(2)O(2) was caffeine-sensitive and blocked in ATM(-/-) cells. Polo-like kinase-3 (Plk3) activity was also activated upon H(2)O(2) treatment, and this activation was ATM-dependent. Recombinant His(6)-Plk3 phosphorylated glutathione S-transferase (GST)-p53 fusion protein but not GST alone. When phoshorylated in vitro by His(6)-Plk3, but not by the kinase-defective mutant His6-Plk3(K52R), GST-p53 was recognized by an antibody specifically to serine 20-phosphorylated p53, indicating that serine 20 is an in vitro target of Plk3. Also serine 20-phosphorylated p53 was coimmunoprecipitated with Plk3 in cells treated with H(2)O(2). Furthermore, although H(2)O(2) strongly induced serine 15 phosphorylation of p53, it failed to induce serine 20 phosphorylation in Plk3-dificient Daudi cells. Ectopic expression of a Plk3 dominant negative mutant, Plk3(K52R), in GM00637 cells suppressed H(2)O(2)-induced serine 20 phosphorylation. Taken together, our studies strongly suggest that the oxidative stress-induced activation of p53 is at least in part mediated by Plk3.
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PMID:Reactive oxygen species-induced phosphorylation of p53 on serine 20 is mediated in part by polo-like kinase-3. 1144 25

The p53 protein is the major tumor suppressor in mammals. The discovery of the p53 homologs p63 and p73 defined a family of p53 members with distinct roles in tumor suppression, differentiation, and development. Here, we describe the biochemical characterization of the core DNA-binding domain of a human isoform of p63, p63-delta, and particularly novel features in comparison with p53. In contrast to p53, the free p63 core domain did not show specific binding to p53 DNA consensus sites. However, glutathione S-transferase-fused and thus dimerized p63 and p53 core domains had similar affinity and specificity for the p53 consensus sites p21, gadd45, cyclin G, and bax. Furthermore, the fold of p63 core was remarkably stable compared with p53 as judged by differential scanning calorimetry (T(m) = 61 degrees C versus 44 degrees C for p53) and equilibrium unfolding ([urea](50%) = 5.2 m versus 3.1 m for p53). A homology model of p63 core highlights differences at a segment near the H1 helix hypothetically involved in the formation of the dimerization interface in p53, which might reduce cooperativity of p63 core DNA binding compared with p53. The model also shows differences in the electrostatic and hydrophobic potentials of the domains relevant to folding stability.
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PMID:High thermostability and lack of cooperative DNA binding distinguish the p63 core domain from the homologous tumor suppressor p53. 1147 76

Polo-like kinase 3 (Plk3, previously termed Prk) contributes to regulation of M phase of the cell cycle (Ouyang, B., Pan, H., Lu, L., Li, J., Stambrook, P., Li, B., and Dai, W. (1997) J. Biol. Chem. 272, 28646-28651). Plk3 physically interacts with Cdc25C and phosphorylates this protein phosphatase predominantly on serine 216 (Ouyang, B., Li, W., Pan, H., Meadows, J., Hoffmann, I., and Dai, W. (1999) Oncogene 18, 6029-6036), suggesting that the role of Plk3 in mitosis is mediated, at least in part, through direct regulation of Cdc25C. Here we show that ectopic expression of a kinase-active Plk3 (Plk3-A) induced apoptosis. In response to DNA damage, the kinase activity of Plk3 was rapidly increased in an ATM-dependent manner, whereas that of Plk1 was markedly inhibited. Recombinant Plk3 phosphorylated in vitro a glutathione S-transferase fusion protein containing p53, but not glutathione S-transferase alone. Recombinant Plk1 also phosphorylated p53 but on residues that differed from those targeted by Plk3. Co-immunoprecipitation and pull-down assays demonstrated that Plk3 physically interacted with p53 and that this interaction was enhanced upon DNA damage. In vitro kinase assays followed by immunoblotting showed that serine 20 of p53 was a target of Plk3. Furthermore, expression of a kinase-defective Plk3 mutant (Plk3(K52R)) resulted in significant reduction of p53 phosphorylation on serine 20, which was correlated with a decrease in the expression of p21 and with a concomitant increase in cell proliferation. These results strongly suggest that Plk3 functionally links DNA damage to cell cycle arrest and apoptosis via the p53 pathway.
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PMID:Plk3 functionally links DNA damage to cell cycle arrest and apoptosis at least in part via the p53 pathway. 1155 30

Drug-metabolizing enzymes are involved in the metabolic activation or detoxification of carcinogens. To evaluate animals developed as models for alternative carcinogenicity testing, we investigated whether or not a gene manipulation including the transgene of ras and the knocking out of a tumor suppressor gene such as p53 or XPA could alter the expression of representative drug-metabolizing enzymes directly or indirectly. Expression of several isoforms of cytochrome P450 (CYP) in the liver of rasH2, p53 (+/-), Tg.AC, and XPA (-/-) mice with or without treatment of prototype inducer. phenobarbital or 3-methylcholanthrene, was analyzed by Western immunoblotting in comparison with their parental strains of mice. In addition, the activities of 3 major phase II enzymes, UDP-glucronosyltransferase, sulfotransferase, and glutathione S-transferase, were compared between the gene-manipulated and the corresponding parental strains of mice. Results demonstrate that XPA gene knockout appeared to increase constitutive expression of CYP2B and CYP3A isoforms. Overexpression of human c-Ha-ras gene or p53 gene knockout appeared to increase constitutive UGT activity toward 4-nitrophenol. The content or activities of almost all other enzymes examined in the present study do not appear to be affected by the gene manipulation.
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PMID:Comparison of the levels of enzymes involved in drug metabolism between transgenic or gene-knockout and the parental mice. 1169 53

The glutathione S-transferase (GST) genes are involved in the metabolism of various carcinogens. Deletion polymorphisms in the GSTM1 and GSTT1 genes and an A-G polymorphism in the GSTP1 gene were investigated in relation to breast cancer risk in 500 breast cancer patients and 395 controls. The effects of the GST genotypes on the frequency and pattern of p53 mutations in 388 breast carcinomas were also studied. A suggestive trend of increasing risk of breast cancer with increasing number of G alleles of the GSTP1 was observed (P for trend, 0.11). The GSTM1 and GSTT1 polymorphisms did not show an association with breast cancer. No increase in risk was observed with a combination of genotypes. A statistically significant association was observed between the GSTT1 genotype and p53 mutation status of the tumors, with patients carrying the GSTT1 null genotype more frequently having mutations in the p53 gene compared with patients with a GSTT1 gene present (24.6% versus 12.4%; P = 0.019). There was also a suggestive trend for the GG genotype of the GSTP1 gene, but it was not statistically significant (P = 0.19). No association was observed with the type or location of mutations. We conclude that the GSTP1 and GSTT1 genes could play a role in carcinogenesis in the breast, possibly through increased frequency of mutations in tumor suppressor genes such as p53.
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PMID:GSTM1, GSTT1, and GSTP1 genotypes in relation to breast cancer risk and frequency of mutations in the p53 gene. 1170 Feb 65

Galectin-7 is normally expressed in all types of stratified epithelia, but is significantly down-regulated in squamous cell carcinomas. This protein was recently found to be highly inducible by p53 in a colon carcinoma cell line, DLD-1, and designated as PIG1 (for p53-induced gene 1). We studied transfectants of HeLa and DLD-1 cells ectopically expressing this protein and found that they were more susceptible to apoptosis than control transfectants. This was observed in apoptosis induced by mechanistically distinct stimuli, suggesting that galectin-7 acts on a common point in the apoptosis signaling pathways. Further analyses of actinomycin D-induced apoptosis demonstrated that galectin-7 expression causes enhanced caspase-3 activity and poly(ADP-ribose) polymerase cleavage, and the potentiation of apoptosis by galectin-7 was completely abrogated by a caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone. In addition, galectin-7 transfectants displayed accelerated mitochondrial cytochrome c release and up-regulated JNK activity upon apoptosis induction. Several lines of evidence indicate that the effect on apoptosis is not due to the lectin functioning extracellularly through interactions with cell surface glycoconjugates. In fact, this lectin is found to localize in nuclei and cytoplasm of the transfectants and the transformed keratinocyte line HaCaT. Therefore, galectin-7 is a pro-apoptotic protein that functions intracellularly upstream of JNK activation and cytochrome c release. DNA microarray analysis revealed genes that are differentially expressed between galectin-7 and control transfectants. Some of them are potentially contributory to this lectin's proapoptotic function and these include redox-related genes monoamine oxidase B, ryanodine receptor 2, and glutathione S-transferase Mu 3.
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PMID:Galectin-7 (PIG1) exhibits pro-apoptotic function through JNK activation and mitochondrial cytochrome c release. 1170 6

Prooxidant effect of chemotherapeutic agents is of significant interest in connection with activation of oxidative stress in cancer cells. Role of development of adaptive antioxidant response to the rise of resistance to cytotoxical effect of doxorubicin (DOX) has been studied in human erythroleukemia K562 cells. Growth of resistance to DOX caused enhancement of antioxidant enzymes (Cu, Zn-SOD, Mn-SOD, catalase) elevation of Mn-SOD activity being predominant. Additional increasing of antioxidant level was elevation of GSH maintenance and level of GST-related enzymes (glutathione peroxidase, glutathione S-transferase, glutathione reductase) in resistance K562/DOX cells. The enhancement of antioxidant system prevented activation of lipid peroxidation. Furthermore, the antioxidant growth caused decrease of level of proteintyrosine kinases, thioredoxin, thioredoxin reductase in contrary to elevation of glutaredoxin activity. Increasing of Bcl-2 and suppression of p53 levels was found to be caused by the change of redox state of K562DOX cells. The data support the suggestion that adaptive antioxidant response to prooxidant effect of DOX promotes the development of cellular drug resistance.
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PMID:[Role of the antioxidant system and redox-dependent regulation of transcription factors bcl-2 and p53 in forming resistance of human K562 erythroleukemia cells to doxorubicin]. 1178 3


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