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)

DNA from archival Papanicolaou stained smears was successfully amplified using the polymerase chain reaction (PCR) to see if it could be used for retrospective genome studies such as detection of the presence of human papilloma virus (HPV) and changes in p53 gene expression. DNA was isolated and purified by treatment with proteinase K, phenol/chloroform, and isoamyl alcohol. Segments of the human beta actin and TGF beta 1 gene were amplified by PCR. Of all stains used in the preparation of Papanicolaou smears, only eosin was detectable as a greenish band in ethidium bromide treated DNA gels under ultraviolet illumination.
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PMID:PCR amplification of DNA from stained cytological smears. 768 6

Phorbol 12-myristate, 13-acetate (PMA) is a known protein kinase C activator (PKC); benzene, chloroform, and toluene have also been reported to be PKC activators. We examined the effects of these three solvents on the phosphorylation of p53 in treated cells. Hyperphosphorylated p53 was found when p53 was immunoprecipitated from rat liver epithelial cell extracts treated with any of the solvents or PMA. The solvents also resulted in hyper-phosphorylation of human p53 produced by transfection of Saos-2 cells with a eucaryotic expression vector. Increased phosphorylation of p53 induced by the solvents was also observed through in vitro assays. Hyperphosphorylation of p53 may be involved in tumor promotion by benzene, toluene and chloroform.
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PMID:Hyperphosphorylation of p53 induced by benzene, toluene, and chloroform. 807 68

DNA was extracted from unstained 5-microns sections of neutral buffered 10% formalin-fixed paraffin-embedded tissue by proteinase K digestion without detergents followed by boiling, proteinase K digestion with ionic detergents with and without phenol chloroform extraction and ethanol precipitation, sonication with proteinase K followed by boiling, or boiling alone. Serial 1:10 dilutions of the extracted DNA were subject to polymerase chain reaction (PCR) amplification of a 255-bp portion of the p53 gene. Digestion with proteinase K without ionic detergents followed by boiling (without phenol chloroform extraction) gave the best yield, enabling visualization of ethidium bromide-stained PCR product from a DNA dilution corresponding to 0.1 mm2 of tissue containing of the order of 10(3) nuclear profiles. Proteinase K digestion with detergents followed by phenol-chloroform extraction was no more effective than simple boiling. Although the success of PCR from preserved tissue will vary with the fixative and size of the amplified fragment, DNA extracted with this optimized method can be used for identification of viruses, loss of heterozygosity, and immunoglobulin gene rearrangements in paraffin-embedded tissue without radioisotopes.
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PMID:Comparison of methods for extracting DNA from formalin-fixed paraffin sections for nonisotopic PCR. 886 37

Meat cooked at high temperatures contains mutagens and carcinogens known as heterocyclic amines (HCA). Cooking temperature and time determine the amount of HCA produced. The present study examined the DNA of liver, colon, and stomach from rats fed a high level of HCA for 27 weeks. Male Sprague-Dawley rats were fed a high-fat AIN-76A-based diet containing 60% by weight cooked beef containing a high level of HCA, especially 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP, 72 ng/g cooked beef), the most abundant HCA in cooked meat products. At the end of 27 weeks the rats were terminated, and small portions of liver, colon, and stomach were quick-frozen in liquid nitrogen. The DNA was isolated from the thawed tissue by phenol-chloroform extraction, and the genomic DNA was analyzed for the presence of PhIP adducts by 32P-postla-beling analysis. The DNA was also used in polymerase chain reactions to amplify the rat p53 and Apc genes, then direct dye-terminator DNA sequencing was carried out. Results showed no PhIP adducts in any tissue. In addition, no signature p53 or Apc gene mutations were seen in colon or stomach DNA. These results indicate that the high level of HCA present in a diet of well-cooked meat does not cause 1) persistent PhIP adducts similar to those produced by feeding pure PhIP at high doses or 2) p53 and Apc gene mutations in nontumor tissue.
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PMID:Absence of PhIP adducts, p53 and Apc mutations, in rats fed a cooked beef diet containing a high level of heterocyclic amines. 963 95

The aim of this study was to evaluate the concordance between the presence of p53 mutations in breast carcinomas expressing the protein by immunohistochemistry. A series of 60 breast carcinomas was evaluated by immunohistochemistry using monoclonal antibodies against p53 protein (DO 7 and PAb 1801). Twenty cases classified as being positive for p53 according to the current approach (if 5% or more of neoplastic cells contained reaction product in the nucleus) were used for molecular studies. These cases were re-assessed semi-quantitatively using a scoring system based on intensity and percentage of stained cells. DNA was phenol-chloroform extracted from microdissected normal and tumour cells obtained from formalin-fixed, paraffin-embedded tissue sections. Mutations in the p53 gene were analysed by SSCP (single strand conformational polymorphism) with primers covering exons 2-3 to 11. Ten out of the 20 p53-positive cases presented mutations detected by SSCP analysis. Mutations have been found in several exons ranging from exon 4 to exon 10. We observed a positive relationship between the presence of mutations and immunohistochemical evaluation of p53 protein expression using a semiquantitative scoring system. All cases with more than 2/3 stained tumour cells and strong intensity of staining exhibited p53 mutations. At variance, no p53 mutations were found in cases with less than 1/3 stained tumour cells and moderate intensity of staining. Therefore, only the identification of positivity for p53 detected by immunohistochemistry did not always reflect the detection of p53 mutations in breast cancer, however the use of a semi-quantitative approach seems to be useful as an indicator of the presence of mutation.
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PMID:P53 in breast carcinomas: association between presence of mutation and immunohistochemical expression using a semiquantitative approach. 989 46

Alterations to p53 seem to be of prognostic significance in soft tissue sarcomas, but their significance for synovial sarcomas has not been studied. We analysed 34 synovial sarcomas in 19 patients for p53 alterations (p53 gene mutations + p53 immunopositivity) and examined this factor for its prognostic value in a group of 15 primary tumours. DNA was prepared from paraffin-embedded tumour material by a modified proteinase K/phenol/chloroform extraction. p53 gene mutations of exons 5-8 were analysed by the PCR-SSCP-sequencing method. p53 protein expression was evaluated by immunohistochemistry using the murine monoclonal antibody DO1. We found two missense mutations (5.9%) and ten p53 immunopositive cases (29.4%). Both tumours with p53 mutations showed p53 protein expression. There was no significant correlation between p53 alteration and histological subtype, age, sex, or tumour size. The 5-year survival rate was 24.1%. Overall survival was significantly reduced in patients having synovial sarcomas with p53 alterations (P<0.001). In the multivariate Cox's analysis, only p53 alterations (P=0.032) and tumour size (P=0.023) emerged as independent prognostic factors. We suggest that p53 alterations may be a useful prognostic indicator in synovial sarcomas, allowing rational clinical treatment and follow-up.
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PMID:Prognostic significance of p53 gene mutations and p53 protein expression in synovial sarcomas. 1052 4

The performance of the p53-/- transgenic (knockout) mouse model was evaluated through review of the data from 31 short-term carcinogenicity studies with 21 compounds tested as part of the International Life Sciences Institute's (ILSI) Alternatives to Carcinogenicity Testing (ACT) project, together with data from other studies which used comparable protocols. As expected based on the hypothesis for the model, a significant number (12/16 or 75%) of the genotoxic human and/or rodent carcinogens tested were positive and the positive control, p-cresidine, gave reproducible responses across laboratories (18/19 studies positive in bladder). An immunosuppressive human carcinogen, cyclosporin A, was positive for lymphomas but produced a similar response in wild type mice. Two hormones that are human tumorigens, diethylstilbestrol and 17beta-estradiol, gave positive and equivocal results, respectively, in the pituitary with p53-deficient mice showing a greater incidence of proliferative lesions than wild type. None of the 22 nongenotoxic rodent carcinogens that have been tested produced a positive response but 2 compounds in this category, chloroform and diethylhexylphthalate, were judged equivocal based on effects in liver and kidney respectively. Four genotoxic noncarcinogens and 6 nongenotoxic, noncarcinogens were also negative. In total (excluding compounds with equivocal results), 42 of 48 compounds or 88% gave results that were concordant with expectations. The technical lessons learned from the ILSI ACT-sponsored testing in the p53+/- model are discussed.
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PMID:P53+/- hemizygous knockout mouse: overview of available data. 1169 60

Human papillomaviruses (HPVs) are major pathogens associated with the development of cancer of the uterine cervix, the most common malignant tumour of women worldwide. Reliable diagnosis of HPV infection, particularly the 'high-risk' types (16/18), may facilitate early identification of 'high-risk' populations for developing cervical cancer and may augment the sensitivity and specificity of primary cervical cancer screening programmes by complementing the conventional Pap test. A simple paper smear method has been developed for dry collection, transport and storage of cervical smears/scrapes at room temperature for subsequent detection of HPV DNA by PCR assay. Imprint biopsies, blood and fine-needle aspirates were also collected by this method. The cervical scrapes or other body fluids were smeared (within 0.5-1 cm diameter) and dried on to sterile small slides made of Whatman 3MM filter paper, and stored individually at room temperature or at 4 degrees C. A small piece (2-3 mm) of the paper smear was punched or cut out with a sterile surgical blade, boiled in an eppendorf tube containing 50 microl of distilled water for 5 min and used directly for PCR amplification. The quality and quantity of DNA derived from paper smears and the results of PCR amplifications for HPV type 16, BRCA1 and p53 genes were identical to those obtained from the same samples following collection in PBS, storage (-70 degrees C) and phenol-chloroform-based DNA extraction. DNA was stable in the paper smears for up to a year, whether stored at room temperature or at 4 degrees C. This method is simple, rapid and cost-effective, and can be effectively employed for large-scale population screening, especially for regions where the specimens are to be transported from distant places to the laboratory.
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PMID:A simple 'paper smear' method for dry collection, transport and storage of cervical cytological specimens for rapid screening of HPV infection by PCR. 1820 98

There are a number of observations that suggest the dsRNA-activated protein kinase, PKR, may play an active role in formation and maintenance of leukemia, including nonrandom chromosomal deletions in acute leukemia as well as truncations and deletions of the PKR gene in some leukemia cell lines. However, there is little direct evidence from patient material that this is so. Here we show that full-length PKR is present but not active in 21 of 28 patient samples from B-cell chronic lymphocytic leukemia (B-CLL). PKR from these patients was unable to auto-activate or phosphorylate substrates but was able to bind dsRNA. Furthermore, the lack of PKR activation was not due to differing levels of the PKR activator, PACT nor of the PKR inhibitor, p58(IPK). We compared PKR status with clinical parameters and disease staging. No differences were found between the 2 groups in terms of staging (modified Rai or Binet), age, CD38 status, p53 status, 11q23 deletion status or CEP12 deletion status. However, there was a significant correlation between deletion in 13q14.3 and lack of PKR activity. We show that B-CLL cells appear to contain a soluble inhibitor of PKR, as lysates from cells lacking PKR activity were able to inhibit exogenous PKR in mixing experiments. Finally, we show suppression of PKR activity was still present following ultrafilitration through a 10,000 Da cutoff filter but was lost upon extraction with phenol/chloroform or by high salt washing. This data suggests loss of PKR activity may contribute to the formation and/or maintenance of CLL.
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PMID:Loss of PKR activity in chronic lymphocytic leukemia. 1496 69

Caesalpinia sappan L. (C. sappan) has been used in Oriental medicine as an antitumor agent. The present study shows the effects of the chloroform extract of C. sappan on cell death in head and neck cancer cell lines. The viability of HNSCC4 and HNSCC31 cells (head and neck cancer cell lines) was noticeably decreased compared to that of HaCaT cells (control group) in the presence of chloroform extract. No significant difference was observed in the viability of HNSCC4 and HNSCC31 cells when compared with HaCaT cells in the presence of n-butanol, methanol, and water extracts. Exposure to the chloroform extract of C. sappan resulted in an increase in the Sub-G1 phase of the cell cycle and condensation and shrinkage of nuclei in the HNSCC4 and HNSCC31 cells. The levels of p53 and p21WAF1/CIP1 were also increased in the HNSCC4 and HNSCC31 cells. The results suggest that the chloroform extract of C. sappan may increase cell death in the HNSCC4 and HNSCC31 cells, which is linked to increased cellular levels of p53 and p21WAF1/CIP1.
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PMID:Caesalpinia sappan induces cell death by increasing the expression of p53 and p21WAF1/CIP1 in head and neck cancer cells. 1604 58


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