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 prognosis for maxillary squamous cell carcinoma (SCC) remains poor, despite advances in combination therapy. Combined treatment with anticancer drugs and radiation therapy is aimed at inducing apoptosis. As apoptosis is regulated by several proteins, we investigated the expression of p53, Bax and Bcl-2 in maxillary SCC before treatment and after preoperative chemoradiotherapy using an immunohistochemical approach. Furthermore, apoptotic cells were visualized using an in situ apoptosis detection kit and the apoptosis index (AI) was defined as the number of positive cancer cells per 1,000 cancer cells. Expression of p53 and Bcl-2 and the Al in 23 maxillary SCCs were not associated with tumor size, lymph node metastasis, clinical stage, frequency of recurrence or 5-year survival rate either before treatment or after preoperative chemoradiotherapy. Bax expression before treatment was not correlated with any clinicopathological factors before treatment. However, no patients in the Bax-positive group (11/22 cases) after preoperative chemoradiotherapy had recurrence of maxillary SCC and all were alive after 5 years, while the 5-year survival rate was 34.1% in Bax-negative patients. These results suggest that the appearance of the Bax protein after preoperative chemoradiotherapy is a significant prognostic marker for maxillary SCC.
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PMID:Appearance of bax protein after preoperative chemoradiotherapy is a prognostic factor in maxillary cancer. 1181 5

We have analyzed by immunocytochemistry the p53 and Bcl-2 proteins expression in 49 patients with B-ALL, T-ALL and AML at the time of initial diagnosis. The diagnosis was based on morphologic and cytochemical criteria and on immunophenotyping. To demonstrate the p53 protein expression, p53 specific mouse antihuman immunoreagent clone DO-1 that recognizes both wild and mutated p53 protein was used. To detect Bcl-2 a monoclonal antibody that recognizes the 26-kD Bcl-2 protein was applied. For evaluation of both proteins a sensitive Immunotech detection kit based on peroxidase labeled streptavidin biotin reagent was utilized. The patients were divided according to the presence or absence of both, nuclear p53 and cytoplasmic Bcl-2 proteins. A relative low frequency of p53 protein expression in B- and T-lineage acute lymphoblastic leukemia has been shown at diagnosis. In AML cases, the frequency of p53 expression was higher than that in ALL. Bcl-2 protein immunoreactivity has been found in the majority of acute leukemia patients. The marked heterogeneity in the percentage of p53 and Bcl-2 positive cells in individual patients was observed. Comparative analysis of the distinct acute leukemia subtypes according to the percentage of p53 and Bcl-2 positive cells showed no significant differences except for p53 protein positivity in relation between T-ALL and AML cases. The samples from healthy subjects used as a control exhibited very low proportion of positively stained cells and significantly differed from p53 as well as Bcl-2 positive cases. p53 and Bcl-2 positivity have not been significantly affected neither by age, sex nor WB C counts. Association between myeloid cells maturation and proportion of p53 and Bcl-2 positive cells was observed. Noteworthy was the inverse relation between the higher proportion of p53 positive cells and low Bcl-2 positivity in some cases of acute leukemia. Although our preliminary results need to be confirmed in a larger group of patients, immunocytochemical analysis of p53 and Bcl-2 proteins, indicators of cell alterations, may help to identify risk patients requiring intensive therapy.
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PMID:Expression of p53 and bcl-2 proteins in acute leukemias: an immunocytochemical study. 1194 43

Using a cultured human colon cancer cell line (Col 2), a structurally diverse group of chemopreventive agents was evaluated for their potential to induce apoptosis. As a result, 1,4-phenylenebis(methylene)selenocyanate (p-xylylselenocyanate; p-XSC) was found to be active in this process. p-XSC, a synthetic organoselenium compound, has been shown to inhibit tobacco-specific 4-(methylnitrosoamino)-(3-pyridyl)-1-butanone-induced tumorigenesis in A/J mouse lung, rat tongue carcinogenesis and colon cancer. Known chemopreventive mechanisms include inhibition of DNA methylation, inhibition of thymidine kinase and reduction of oxidative DNA damage. In order to assess apoptosis induction, the cells were exposed to various concentrations of test substances for 48 hours. Enrichment of mono- and oligonucleosomes in the cytoplasm was monitored as an indication of apoptosis using an ELISA kit. As a result, p-XSC caused dose-dependent enrichment of fragmented nucleosomes. In further studies, p-XSC was found to induce DNA laddering in a dose-dependent manner, while apoptotic cells accumulated in a time-dependent manner up to 96 hours. The apoptotic peaks after treatment of p-XSC were also found as confirmed by the flow cytometric analysis of cell cycle distribution. In an additional study, however, p-XSC-mediated apoptosis was not shown to be dependent on p53 expression. Taken together, these results suggest that induction of apoptosis is one possible mechanism for the cancer chemopreventive activity mediated by p-XSC.
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PMID:Induction of apoptosis by 1,4-phenylenebis(methylene)selenocyanate in cultured human colon cancer cells. 1201 40

p63 is a p53-homologous nuclear protein that appears to play a crucial role in regulation of stem cell commitment in squamous and other epithelia. In this study, p63 expression was examined in benign lung and in neoplasms of pulmonary origin. Eighty sections from routinely fixed and processed archival bronchoscopic biopsy or lobectomy specimens were pretreated with citric acid (pH 6.0) for antigen retrieval, then incubated overnight with anti-p63 monoclonal antibody 4A4. Slides were stained using a streptavidin-biotin kit and diaminobenzidine as chromagen, and were counterstained with hematoxylin. In normal lung, p63 intensely stained nuclei of bronchial reserve cells but did not stain ciliated cells, alveolar epithelial cells, or nonepithelial cells. The lower strata of squamous metaplastic bronchial epithelium stained positively. All squamous-cell carcinomas stained positively (n = 30). In some well-differentiated carcinomas, staining was found at the periphery of tumor nests but was negative in central zones showing squamous maturation. Poorly differentiated carcinomas showed very high proportions (80% to 100%) of p63-positive nuclei. All small-cell carcinomas were p63 negative (n = 9). Staining of bronchioloalveolar carcinomas (n = 7) and adenocarcinomas (n = 23) was variable: some tumors showed no detectable staining, others showed heterogeneously positive staining. Adenosquamous carcinomas (n = 5) displayed a unique basalar staining pattern. Carcinoid tumors were almost entirely negative (n = 5). We conclude that p63 is expressed in benign bronchial stem cells, in neoplastic cells with either squamous differentiation or squamous differentiating potential, and in a subpopulation of adenocarcinomas. p63 immunostaining may also aid in some histopathologic distinctions, such as in small biopsies where the differential diagnosis is poorly differentiated squamous carcinoma versus small-cell carcinoma. A stem cell biology-based classification system for squamous carcinomas is proposed.
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PMID:P63 in pulmonary epithelium, pulmonary squamous neoplasms, and other pulmonary tumors. 1237 18

Several techniques have been proposed for flow cytometric evaluation of intracellular antigens. This approach is particularly important for detection at the single cell level of proteins which correlate to tumour progression. Bcl-2 and p53 are two of the most relevant proteins. In the present study we have compared five different cell fixation-permeabilisation protocols and nine fluorochrome-conjugated (FITC or PE) monoclonal antibodies (mAb): four mAb directed against Bcl-2 and five against p53. For detection of Bcl-2 we have analysed three Bcl-2 positive cell lines (K562, Daudi and MCF-7), and peripheral blood samples obtained from nine healthy subjects. To distinguish internal positive (lymphocytes) and negative control cells (granulocytes), it was necessary to perform simultaneous detection of surface and intracellular antigens. For detection of p53 three cell lines, two p53 positive (Raji and CEM) and one p53 negative (HL-60), were analysed. Using these cells we have performed a combined analysis of the efficiency of monoclonal antibodies and sample preparation techniques. In conclusion, clones 124-FITC and Bcl-2/100-PE (Bcl-2), and clones BP53,12-FITC and G59-12-PE (p53) provided the highest specific fluorescence intensity of the respective markers independent of cell preparation protocols. Importantly, our results show that mAb background may depend on the specific fixation/permeabilisation kit and that mAb titration using negative and positive control cells is essential to determine the specificity and the sensitivity of the mAb used.
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PMID:Intracellular detection of Bcl-2 and p53 proteins by flow cytometry: comparison of monoclonal antibodies and sample preparation protocols. 1259 45

p63 proteins are p53 homologs that are postulated to regulate squamous stem cell commitment. An immunohistochemical survey of p63 expression in normal thyroid and in reactive, neoplastic, and inflammatory thyroid disorders was performed. Sections from routinely fixed and processed archival thyroidectomy specimens were pretreated with citric acid, pH 6.0, for antigen retrieval, then incubated overnight with anti-p63 monoclonal antibody 4A4. Slides were stained using a streptavidin-biotin kit and diaminobenzidine as a chromagen, and then were counterstained with hematoxylin. The results showed that p63 expression was negative in normal thyroid tissue, nodular goiters, and oncocytic follicular adenomas. Positivity was rare and weak in follicular adenomas. p63-positive foci were commonly found in Hashimoto's thyroiditis (1 or more foci in 78.8% of cases), but rare in Graves' disease. Twenty-seven of 33 papillary thyroid carcinomas (81.8%) displayed p63-positive foci. Staining was uncommon in follicular carcinomas and rare in medullary carcinomas. One case of insular carcinoma was p63-positive. All squamoid structures were p63-positive; p63-positive structures morphologically consistent with solid cell nests were also identified. Based on the results of this study, we conclude that p63 is commonly expressed in papillary thyroid carcinoma and in Hashimoto's thyroiditis. Given the debated association of papillary thyroid carcinoma with Hashimoto's thyroiditis, it is possible that p63 expression may be a potential pathobiologic link between the two disorders. The finding of p63 in benign squamoid nests supports a possible interrelationship between these structures and both Hashimoto's thyroiditis and papillary carcinoma. The high percentage of papillary carcinomas with p63-positive foci appears to distinguish papillary carcinoma from other neoplasms originating in the thyroid.
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PMID:Expression of p63 in papillary thyroid carcinoma and in Hashimoto's thyroiditis: a pathobiologic link? 1450 36

Tumour growth and its progression to a metastatic phenotype involves a serious of genetic events with abnormal activation of oncogenes or inactivation of tumour suppressor genes and others genes connected with proliferation, apoptosis and neovascularisation. The aims of the study were to determine the possible prognostic value of angiogenesis, proliferation index Ki67, p53 and bcl-2 proteins expression in patients with laryngeal cancer. The group of 151 patients with laryngeal cancer, surgically treated with minimum 5 years observation, was multi-variously analysed. Paraffin--embedded tissue sections from each case were stained with a monoclonal antibody raised against FVIII antigen, p53 and bcl-2 proteins and Ki67 proliferation antigen using a peroxidase labelled streptavidin--biotin kit in standard immunohistochemistry techniques. In univariate analysis: staging IV, tumour size T4, nodal metastasis N2 and N3, local and nodal recurrences, high expression of Ki67 and P53, high (over median) IA measured as number of microvessels with FVIII expression were significantly associated with shortened overall survival. Disease-free survival was related to: proliferation index Ki67, expression of P53 protein and angiogenesis measured as microvessels density with expression of FVIII antigen. In multivariate analysis the most important death risk factors for overall survival were: tumour size, nodal metastasis, local and nodal recurrences, P53 protein expression and IA measured as number of microvessels with FVIII expression. In multivariate analysis of disease-free survival only P53 protein expression, proliferative index Ki67 and expression of FVIII had independent prognostic value. Intensity of angiogenesis, proliferation index of Ki67 antigen and expression of P53 protein were independent predictors of patients with laryngeal cancer outcome. In contrary Bcl2 protein seems to be useless in these patients.
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PMID:[Survival of patients with laryngeal cancer and some prognostic factors]. 1452 74

Study of expression of p53 oncoprotein in several precancerous and cancer have been done, but only one literature is available regarding p53 expression in Oral Sub Mucous Fibrosis (OMSF), hence this study was taken up (i) to determine the expression of aberrant p53 in Oral Sub Mucous Fibrosis (OSMF) and Oral Squamous cell carcinoma (SCC) patients. (ii)To study correlation if any between p53 expression and degree of dysplasia in OSMF and SCC patients and (iii)To study correlation if any between p53 expression and habits in OSMF and SCC patients. Study Design consists of biopsy specimens of 38 cases of OSMF and 37 cases of Squamous cell carcinoma were subjected for staining by immunohistochemistry for p53 protein using LSAB visualization system kit. Clinical details along with habits were recorded and the data analyzed with t- test and chi- square test. Results of the study reveals 18 cases of OSMF and 26 cases of SCC were positive for p53 protein. Only 4 cases of SCC showed (++)grade and the rest all had (+)grade. Out of 75 patients, 65 had the habit of smoking and chewing, 4 patients history of habit was not known. Among patients with habits (65), 40 specimens were +ve for p53 stain and 2 out of 6 without history of habit, 2 out of 4 unknown history of habit took up p53 stain. To conclude study showed higher percentage of p53 positive cells in oral cancer cases when compared to oral sub mucous fibrosis cases. It suggests p53 expression may correlate with increase in dysplasia or malignant transformation. Both smoking and chewing habits had a significant role in p53 positive expression.
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PMID:p53 aberrations in oral sub mucous fibrosis and oral cancer detected by immunohistochemistry. 1532 87

The aim of this study was to find the correlation between serum p53 and carcinoma of the bladder and to investigate whether serum p53 protein can be used as a tumor marker for p53 gene alteration. The study included patients with carcinoma of the bladder and controls. Serum p53 protein estimation was done with an ELISA kit. There were 23 patients with superficial and 17 with invasive carcinoma. The median serum p53 was 31.5 U/ml in superficial and 41 U/ml in invasive cancer. This was significantly higher than the mean value (16.4 U/ml) of controls. Serum p53 rises in patients with carcinoma of the bladder and correlates with the grade of the disease . It can therefore be used as a tumor marker for bladder cancer.
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PMID:Serum p53 and bladder cancer: can serum p53 be used as a tumor marker? 1550

The NAD+-dependent protein deacetylase family, Sir2 (or sirtuins), is important for many cellular processes including gene silencing, regulation of p53, fatty acid metabolism, cell cycle regulation, and life span extension. Resveratrol, a polyphenol found in wines and thought to harbor major health benefits, was reported to be an activator of Sir2 enzymes in vivo and in vitro. In addition, resveratrol was shown to increase life span in three model organisms through a Sir2-dependent pathway. Here, we investigated the molecular basis for Sir2 activation by resveratrol. Among the three enzymes tested (yeast Sir2, human SIRT1, and human SIRT2), only SIRT1 exhibited significant enzyme activation ( approximately 8-fold) using the commercially available Fluor de Lys kit (BioMol). To examine the requirements for resveratrol activation of SIRT1, we synthesized three p53 acetylpeptide substrates either lacking a fluorophore or containing a 7-amino-4-methylcoumarin (p53-AMC) or rhodamine 110 (p53-R110). Although SIRT1 activation was independent of the acetylpeptide sequence, resveratrol activation was completely dependent on the presence of a covalently attached fluorophore. Substrate competition studies indicated that the fluorophore decreased the binding affinity of the peptide, and, in the presence of resveratrol, fluorophore-containing substrates bound more tightly to SIRT1. Using available crystal structures, a model of SIRT1 bound to p53-AMC peptide was constructed. Without resveratrol, the coumarin of p53-AMC peptide is solvent-exposed and makes no significant contacts with SIRT1. We propose that binding of resveratrol to SIRT1 promotes a conformational change that better accommodates the attached coumarin group.
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PMID:Mechanism of human SIRT1 activation by resveratrol. 1574 5


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