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)

The carcinogenic and metastatic processes are thought to consist of a sequence of steps, and animal models featuring highly metastatic lesions are clearly necessary to allow analysis of the whole process of transformation from preneoplastic changes to high grade metastatic tumors, and to access effectiveness of therapeutic treatments of advanced cancers in vivo. The purpose of the present study was to establish a model and to screen for reported genetic alterations in induced lesions. In the present study, it was confirmed that lung metastasis of hepatocellular carcinomas (HCCs) induced in male F344 rats by N-nitrosomorpholine (NNM), given in the drinking water at a dose of 120 ppm for 24 weeks, was significantly enhanced by additional carcinogenic pretreatments and that a single i.p. injection of 100 mg/kg body weight N-diethylnitrosamine (DEN) alone was sufficient for that purpose. Molecular biological analyses of the induced lesions revealed point mutations in the p53 gene in 60.9% of HCCs, and elevated expression of mRNAs for p53, c-myc, c-fos, TGF-alpha, TGF-beta1, alpha-fetoprotein, GST-P, and GGT, and decreased mRNA expression of EGF and EGFR in HCCs when compared to controls. No obvious association of gene alterations with metastatic potential of primary tumors was found except for an increase in the incidence of p53 mutations. Since the process of metastasis is thought to be sequential and selective, further comparative analysis of metastatic and primary lesions should clarify the mechanisms involved in the multi-step process of metastasis.
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PMID:Highly metastatic hepatocellular carcinomas induced in male F344 rats treated with N-nitrosomorpholine in combination with other hepatocarcinogens show a high incidence of p53 gene mutations along with altered mRNA expression of tumor-related genes. 902 67

Although the relationship among different biologic markers of breast cancer has been shown to be important in predicting cancer behavior, expression of these markers can be an attribute of the population under study. Breast cancer is the most common malignancy among Egyptian women. We have studied a number of prognostic tumor markers in infiltrating ductal carcinoma in a group of Egyptian women and have correlated our results with traditional histologic parameters of behavior such as tumor nuclear grade and lymph node status. Seventy-five cases of infiltrating ductal breast cancer were evaluated from pathology archives. Formalin-fixed paraffin-embedded sections were immunohistochemically stained for PCNA, p53, c-erB-2, metallothionein, cathepsin-D, and GST-pi using specific antibodies and a standard avidin-biotin method. Most high-grade tumors were associated with higher PCNA expression and p53 abnormality. There was a significant difference between node-negative and node-positive tumors with regard to their metallothionein content; other markers, however, did not differ significantly between node-negative and node-positive tumors. PCNA expression, metallothionein expression, and p53 mutation appear to be markers of aggressive tumor behavior in Egyptian women with breast cancer.
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PMID:Immunohistochemical markers of tumor prognosis in breast cancer in Egypt. 916 36

We have discovered a novel function of the SV40 T antigen and the adenovirus E1A proteins: the ability to downregulate the endogenous expression of an important detoxification enzyme, glutathione S-transferase alpha (GST alpha). GST alpha mRNA is much less abundant in rat and human cells that express SV40 T antigen than in the parental cell lines. This GST alpha downregulation does not require expression of SV40 small t antigen or complex formation between large T antigen and p53, p300, or the pRb family of proteins. As might be predicted, cells that express SV40 T antigen are more sensitive than normal cells to alkylating drugs, which GST alpha is known to detoxify. Finally, GST alpha expression is also downregulated in cells that express the adenovirus E1A proteins. We propose that by downregulating GST alpha expression and inactivating p53 function, SV40 and adenovirus may contribute to the initiation of, or the progression toward, malignancy. Thus, in their quest to establish persistent infections, these viruses may inadvertently make the cellular environment more permissive for tumorigenesis.
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PMID:SV40 and adenovirus may act as cocarcinogens by downregulating glutathione S-transferase expression. 920 Dec 22

The A-G polymorphism at codon 104 in the glutathione S-transferase P1 (GSTP1) gene was examined in 138 male lung cancer patients and 297 healthy controls. The patients had significantly higher frequency of the GG genotype (15.9%) and a lower frequency of AA (38.4%) than the controls (9.1% and 51.5%, respectively). The level of hydrophobic DNA-adducts were determined in lung tissue from 70 current smokers. Patients with the GG genotype had a significantly higher adduct level than patients with AA (15.5 +/- 10.2 vs 7.9 +/- 5.1 per 10(8) nucleotides, P = 0.006). We also analyzed the deletion polymorphism in the GSTM1 gene in 135 male patients and 342 controls. The patients were stratified according to histology, smoking dose, age, adduct level and mutational types found in the tumors (Ki-ras and p53 genes). The results consistently indicated that the GSTM1 null genotype was associated with a slightly increased lung cancer risk. When the combined GST M1 and P1 genotypes were examined, patients with the combination null and AG or GG had significantly higher adduct levels than all other genotype combinations (P = 0.011). The distribution of combined genotypes was also significantly different in cases and controls, mainly due to increased frequency of the combination GSTM1 null and GSTP1 AG or GG among patients.
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PMID:Genotypes of glutathione transferase M1 and P1 and their significance for lung DNA adduct levels and cancer risk. 923 Feb 69

p53 is thought to function in the maintenance of genomic stability by modulating transcription and interacting with cellular proteins to influence the cell cycle, DNA repair and apoptosis. p53 mutations occur in >50% of human cancers, and cells which lack wild type p53 accumulate karyotypic abnormalities such as amplifications, deletions, inversions and translocations. We propose that p53 hinders these promiscuous recombinational events by interacting with cellular recombination and repair machinery. We recently reported that p53 can directly bind in vivo to human Rad51 (hRad51) protein and in vitro to its bacterial homologue RecA. We used GST-fusion and his-tagged protein systems to further investigate the physical interaction between p53 and hRad51, homologue of the yeast Rad51 protein that is involved in recombination and DNA double strand repair. The hRad51 binds to wild-type p53 and to a lesser extent, point mutants 135Y, 249S and 273H. This binding is not mediated by a DNA or RNA intermediate. Mapping studies using a panel of p53 deletion mutants indicate that hRad51 could bind to two regions of p53; one between amino acids 94 and 160 and a second between 264 and 315. Addition of anti-p53 antibody PAb421 (epitope 372-381 amino acids) inhibited the interaction with hRad51. In contrast, p53 interacts with the region between aa 125 and 220 of hRad51, which is highly conserved among Rad51 related proteins from bacteria to human. In Escherichia coli ecA protein, this region is required for homo-oligomerization, suggesting that p53 might disrupt the interaction between RecA and Rad51 subunits, thus inhibiting biochemical functions of Rad51 like proteins. These data are consistent with the hypothesis that p53 interaction with hRAD51 may influence DNA recombination and repair and that additional modifications of p53 by mutation and protein binding may affect this interaction.
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PMID:Interaction of p53 with the human Rad51 protein. 938 May 10

In contrast to intrinsic drug resistance, induced multidrug resistance in gastric cancer cells has not been well studied. Therefore, two doxorubicin-resistant cell lines, (SNU-1DOX, SNU-16DOX), were derived in vitro from gastric carcinoma cell lines (SNU-1, SNU-16) respectively, and their characteristics were investigated. These resistances were not associated with overexpression of mdrl, multidrug resistance associated protein 1 (MRP1), pi or liver class of glutathione S transferase (GST pi, GSTL), heat shock protein 70 (HSP70), p53 or transglutaminase C (TGC). Levels of p21WAF1 RNA and topoisomerase II protein were decreased in the SNU-16DOX, but not in SNU-1DOX. However, the subsequent enzyme activity of topoisomerase II in SNU-16DOX was not decreased, but rather increased in SNU-16DOX. Furthermore, both resistant cell lines showed lower uptake and higher efflux of doxorubicin and induced cross-resistance to etoposide and vincristine in addition to doxorubicin, indicating a multi-drug resistance phenotype. In summary, we report two gastric carcinoma cell lines exhibiting induced multidrug resistance phenotype and suggest that mdrl, MRP1, GST, TGC, HSP70 and p53 do not play important roles in induced drug resistance in these cell lines. The role of changes in topoisomerase II activity and/or protein is still inconclusive, and p21WAF1 is associated with induced multidrug resistance in the SNU-16DOX gastric carcinoma cell line.
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PMID:Characteristics of human gastric carcinoma cell lines with induced multidrug resistance. 941 98

Squamous cell carcinomas of the head and neck are a heterogeneous group of tumours with regard to anatomical site, natural history and response to various treatments. Assessment of the role of biomarkers as indicators of prognosis or response to treatment is thus complex. In the last decade, different biomarkers have been investigated in the search for objective and reproducible indicators of prognosis. In 69 squamous cell carcinomas of the oral cavity or oropharynx from patients treated with radical surgery alone, we determined cell kinetics, evaluated as in vitro 3H-thymidine labelling index (TLI), p53, bcl-2 and glutathione S-transferase pi (GST pi) expression, by using immunohistochemical methods. The biological variables were unrelated to one another or to established clinical and pathological prognostic factors. Univariate analysis showed that a low proliferative activity was associated to a significantly higher risk of death than that observed in patients with a high TLI, whereas p53, bcl-2 and GST pi expression did not provide prognostic information. Multivariate analysis showed that cell proliferation, gender and nodal status retained their clinical relevance. In the subset of node-negative patients, TLI and p53 expression were indicators of survival. Moreover, the combined analysis of TLI and p53 expression identified a subgroup of node-negative patients with slowly proliferating and highly p53-expressing tumours who died within 1 year of radical surgery. These results indicate that in patients with operable oral cavity and oropharyngeal cancer, biomarkers can provide important information on clinical outcome.
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PMID:Biological indicators of survival in patients treated by surgery for squamous cell carcinoma of the oral cavity and oropharynx. 950 24

Progression through the cell cycle is controlled by the induction of cyclins and the activation of cognate cyclin-dependent kinases. The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor lovastatin induces growth arrest and cell death in certain cancer cell types. We have pursued the mechanism of growth arrest in PC-3-M cells, a p53-null human prostate carcinoma cell line. Lovastatin treatment increased protein and mRNA levels of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1), increased binding of p21 with Cdk2, markedly inhibited cyclin E- and Cdk2-associated phosphorylation of histone H1 or GST-retinoblastoma protein, enhanced binding of the retinoblastoma protein to the transcription factor E2F-1 in vivo, and induced the activation of a p21 promoter reporter construct. By using p21 promoter deletion constructs, the lovastatin-responsive element was mapped to a region between -93 and -64 relative to the transcription start site. Promoter mutation analysis indicated that the lovastatin-responsive site coincided with the previously identified transforming growth factor-beta-responsive element. These data indicate that in human prostate carcinoma cells an inhibitor of the HMG-CoA reductase pathway can circumvent the loss of wild-type p53 function and induce critical downstream regulatory events leading to transcriptional activation of p21.
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PMID:Inhibition of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase pathway induces p53-independent transcriptional regulation of p21(WAF1/CIP1) in human prostate carcinoma cells. 955 23

We investigated the utility of examining biological markers to predict chemoresponse and survival. The subjects consisted of 39 unresectable gastric cancer patients treated with a combination of 5-fluorouracil and cis-platinum. The expression of p53, bcl-2, thymidylate synthase (TS), glutathione S-transferase pi (GST-pi), and vascular endothelial growth factor (VEGF) in the formalin-fixed biopsy samples of primary tumors before chemotherapy was examined immunohistochemically. The positive rate for VEGF, bcl-2, TS, p53, and GST-pi was 51, 10, 46, 38, and 69%, respectively. VEGF-positive cases showed a higher response rate than did negative cases (11 of 20 versus 2 of 19 cases; P = 0.0057). The cases that were negative for p53, TS, bcl-2, and GST-pi were more likely to respond to chemotherapy than the cases that were positive for these markers. The 10 cases having 4 or 5 favorable phenotypes (VEGF positive, p53 negative, bcl-2 negative, TS negative, and GST-pi negative) survived longer than the remaining 29 cases (P = 0.0069). Multivariate analysis revealed that the number of favorable phenotypes (> or = 4 versus < or = 3) had a greater impact on survival than performance status (0 versus 1 or 2), age (> 60 years versus < or = 60 years), macroscopic type (scirrhous versus nonscirrhous), histological type (intestinal versus diffuse), or tumor extent (locally advanced versus metastatic). Immunohistochemical examination of biological markers in biopsy samples may be useful in predicting the clinical outcome of unresectable gastric cancer patients treated with 5-fluorouracil and cis-platinum.
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PMID:Biological markers as a predictor for response and prognosis of unresectable gastric cancer patients treated with 5-fluorouracil and cis-platinum. 962 64

Previous reports have documented an attenuated p53 response to DNA damage in hepatocytes isolated from enzyme-altered foci (EAF). Here, we have studied this p53 response in vivo in rats with EAF. These animals received repeated doses of diethylnitrosamine (DEN) for 6 weeks and a challenging dose 24 h before death. Liver sections were then analysed using an immunohistological procedure for p53, or a double-staining procedure for p53 and glutathione-S-transferase pi (GST-P). In control rats or rats with EAF not given the challenging dose of DEN, there was no p53 staining. In control rats, only given the challenging dose of DEN, there was a centrilobular p53 nuclear staining that co-localized with TUNEL staining. In an experiment involving four rats with EAF 389 +/- 39 hepatocytes/mm2 of non-EAF tissue stained positively for p53, while the corresponding value for EAF tissue was 27.6 +/- 7.5. Thus, p53-positive cells were 14.6-fold more frequent in non-EAF than in EAF tissue. In many EAF no p53-positive cells were seen at all and 83% of the EAF demonstrated <20% of the number of p53-positive cells seen in non-EAF tissue. Very few EAF had as high a proportion of p53-positive cells as did the average non-EAF tissue. EAF >0.06 mm2 had significantly fewer p53-positive cells than smaller EAF. The ratio of p53 expression in non-EAF tissue and large EAF was 32.6. In a control experiment, four EAF-bearing rats were used as donors to prepare primary cultures of hepatocytes. After 24 h of exposure to DEN, many of the cultured cells became p53-positive. Among GST-P-negative hepatocytes, 12.8% were p53-positive, whereas only 0.25% of the GST-P-positive hepatocytes were p53-positive. Literature data suggest that the altered xenobiotic metabolism in EAF may give rise to a 3-4-fold difference in DNA damage between non-EAF and EAF tissues. It is concluded that GST-P-positive EAF hepatocytes have an attenuated p53 response to DNA damage. This attenuated response may facilitate clonal expansion of EAF under stress induced by DNA-damaging chemicals.
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PMID:Wild-type p53 expression in liver tissue and in enzyme-altered foci: an in vivo investigation on diethylnitrosamine-treated rats. 968 82


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