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)

Four new permanent cell lines (RCC-A, -B, -C, and -D) derived from different human renal cell carcinomas of the clear cell type were established in tissue culture. The cell lines displayed characteristic differences in cell size and shape, which allowed individual identification by phase contrast microscopy. Ultrastructurally, the cell lines exhibited varying amounts of cytoplasmatic glycogen and lipid. Immunohistochemistry revealed co-expression of vimentin and cytokeratin in all cell lines. The mean population doubling time ranged from 27 h (RCC-A) to 104 h (RCC-D). RCC-B and -C cells produced slowly growing tumours after heterotransplantation into nude mice, whereas RCC-A and RCC-D cells were non-tumorigenic. The modal chromosome number was either near-diploid (RCC-A, -B, and -C) or near triploid (RCC-D). Clonal abnormalities affecting the short arm of chromosome 3 were seen in all cell lines. Northern blot analysis revealed no expression of the proto-oncogenes c-fos, c-ros, and c-mos, whereas c-Ki-ras expression was observed in all cell lines. Expression of c-myc was observed in RCC-A, RCC-B, and RCC-D cells, whereas c-raf expression could be detected in RCC-B and RCC-D. Tumour suppressor gene p53 mRNA was observed in the cell line RCC-D.
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PMID:Cytomorphological, cytogenetic, and molecular biological characterization of four new human renal carcinoma cell lines of the clear cell type. 751 57

The combined efforts of a number of investigators have led to the identification of the VHL gene, which appears to function as a tumor suppressor gene and is implicated in both sporadic and familial forms of RCC. These findings should increase our understanding of the molecular biology of this malignancy; however, there is much work to be done. Identification of the mechanism of inactivation of the VHL gene, as well as the structure and function of the VHL gene product, ultimately may provide clinicians with greater understanding of this malignancy as well as with methods for earlier diagnosis. The role of other tumor suppressor genes, such as p53, is incompletely understood. It is hoped that the techniques that have been applied to the study of RCC also will result in advances in our knowledge of other urologic malignancies.
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PMID:Renal cell carcinoma. Molecular genetics and clinical implications. 779 82

In this study both the incidence and pattern of p53 over-expression in various histological subtypes of a series of 36 cases of renal cell Grawitz carcinoma, partially studied in a previous paper, were analyzed. This series consisted of these histologic subtypes: clear cell non papillary (18 cases), clear cell papillary (2 cases), granular cell (5 cases), mixed (clear and granular cell) (9 cases) and spindle cell (2 cases). At present, our aim was, firstly, to see which were the best technical conditions for detection of p53 in the available paraffin-embedded tumor specimens, using several antibodies, specific for various epitopes; secondly, to investigate if some relation might exist between this expression and the histological features of these tumors. Twenty-five per cent (9/36 cases) resulted p53 immunoreactive, the highest percentage being represented in the papillary clear and granular cell carcinomas; low expression was detected in 11 cases (30%) and no reactivity in 16 cases (44%). Neither technical or dilution modifications proved to transform these latter results; however, detection was maximal using the CM-1 polyclonal rabbit antiserum. Thus, in RCC, expression of p53, analyzed in the light of the cytogenetic characterization through a literature review, resulted at low frequency. This finding means that mutation of the p53 gene are not frequent in the neoplastic transformation in RCC. Nevertheless, in spite of the small number of cases and of the short follow-up period of this study, detection of p53 positivity in tumors with either high grade and stage or high proliferative activity could suggest that p53 mutations lead to tumors of a more aggressive type.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:p53 expression in human renal cell carcinoma: an immunohistochemical study and a literature outline of the cytogenetic characterization. 780 90

Significant research progress over the last few years has identified several major genetics contributors to RCC. A new classification of RCC validated by cytogenetic and molecular studies has been proposed including nonpapillary, papillary, chromophobe and oncocytic tumors. The cytogenetic analysis of patients with familial RCC, VHL disease and sporadic RCC have shown that WHL gene located on chromosome 3P 25 is a tumor suppressor gene. Other genes may be involved in the development of RCC, however with a less important incidence than VHL gene. Mutations of Rb and P53 genes can be associated with metastatic disease, mutations of the ras gene is rare whereas elevated level of myc oncogene are frequent but of little prognostic value. Controversial the role of ploidy and proliferation markers as independent prognostic factors.
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PMID:Molecular genetics of renal cell carcinoma. 939 88

An immunohistochemical study was conducted to examine the expression of p53 and bcl-2 proteins in RCC (renal cell carcinoma) with sarcomatoid change in order to determine whether abnormalities in those proteins are associated with an enhanced malignant potential of RCC. Paraffin-embedded tissues from 11 patients with RCC, in which sarcomatoid change was prominent, were stained using anti-p53, bcl-2 and Ki-67 antibodies. Immunoreactivities for these antibodies were compared between the sarcomatoid components and corresponding basic histologic (clear or papillary) components in individual cases. Measurement of the mean nuclear areas of each component was also performed using an image analyzer system. There was no substantial increase in immunoreactivity for p53 or bcl-2 proteins in sarcomatoid components as compared with basic components. In contrast, the percentage of Ki-67-positive cells and the mean nuclear area were significantly larger in sarcomatous components than in basic components. The expression of p53 and bcl-2 proteins was not likely to play a major role in the sarcomatoid change of RCC.
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PMID:Immunohistochemical expression of p53 and bcl-2 proteins is not associated with sarcomatoid change in renal cell carcinoma. 1042 17

Five-year overall survival after radical nephrectomy in pT3N0M0 renal cell carcinoma is 35-50%. In light of immunotherapy, which has shown some activity in advanced diseases with increasing efficacy in limited metastatic invasion, we decided to explore the theoretical advantage of adjuvant immunotherapy in radically resected stage pT3N0M0 renal cell carcinoma. We studied several factors including tumor size, nuclear grade, mean nuclear area and expression of p53 protein to find out which factor is concerned with disease progression. A total of 10 patients with pT3N0M0 RCC who received radical nephrectomy from February 1992 to April 1999 were randomly assigned to receive treatment with either interferon-alpha alone or interferon-alpha plus vinblastine. Eight patients with pT3N0M0 RCC who received only radical nephrectomy from January 1984 to February 1993 were analyzed and the results were compared with the first group. Six out of 10 (60%) patients in the adjuvant immunotherapy group are alive with no evidence of disease. Metastases were documented in 4 patients (40%) with a median interval to progression of 17.5 months. All of them died of tumor. In the surgery only group, 5 out of 8 patients (62.5%) are still alive with no evidence of disease. Two patients (25%) developed distant metastases and both of them died of tumor. The median progression interval was 11 months. There were no statistical differences in time to progression and survival rate between the two groups. In the univariate analysis using a log-rank test, the expression of p53 protein seemed to be associated with shorter survival (p = 0.0591). However, in the multivariate analysis using Cox's proportional hazard model, no parameter had significant independent prognostic value. We concluded that adjuvant immunotherapy did not improve the survival of patients with pT3N0M0 RCC. Furthermore, we failed to find significant prognostic factors in patients with pT3N0M0 RCC.
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PMID:The role of adjuvant immunotherapy after radical nephrectomy and prognostic factors in pT3N0M0 renal cell carcinoma. 1069 24

A recent analysis of gene expression in renal cell carcinoma cells led to the identification of mRNAs whose translation was dependent on the presence of the von Hippel-Lindau (VHL) tumor suppressor gene product, pVHL. Here, we investigate the finding that pVHL-expressing RCC cells (VHL(+)) exhibited elevated levels of polysome-associated p53 mRNA and increased p53 protein levels compared with VHL-defective (VHL(-)) cells. Our findings indicate that p53 translation is specifically heightened in VHL(+) cells, given that (i) p53 mRNA abundance in VHL(+) and VHL(-) cells was comparable, (ii) p53 degradation did not significantly influence p53 expression, and (iii) p53 synthesis was markedly induced in VHL(+) cells. Electrophoretic mobility shift and immunoprecipitation assays to detect endogenous and radiolabeled p53 transcripts revealed that the RNA-binding protein HuR, previously shown to regulate mRNA turnover and translation, was capable of binding to the 3' untranslated region of the p53 mRNA in a VHL-dependent fashion. Interestingly, while whole-cell levels of HuR in VHL(+) and VHL(-) cells were comparable, HuR was markedly more abundant in the cytoplasmic and polysome-associated fractions of VHL(+) cells. In keeping with earlier reports, the elevated cytoplasmic HuR in VHL(+) cells was likely due to the reduced AMP-activated kinase activity in these cells. Demonstration that HuR indeed contributed to the increased expression of p53 in VHL(+) cells was obtained through use of RNA interference, which effectively reduced HuR expression and in turn caused marked decreases in p53 translation and p53 abundance. Taken together, our findings support a role for pVHL in elevating p53 expression, implicate HuR in enhancing VHL-mediated p53 translation, and suggest that VHL-mediated p53 upregulation may contribute to pVHL's tumor suppressive functions in renal cell carcinoma.
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PMID:Influence of the RNA-binding protein HuR in pVHL-regulated p53 expression in renal carcinoma cells. 1451 80

Two cell lines that exemplify erythropoietin (EPO) receptor-positive tumors, human renal carcinoma cell lines RCC and the myelomonocytic leukemia cell line U937, were investigated for the apoptosis-modulatory potential of EPO. Cells cultured in the presence of EPO exhibited an elevated apoptotic response to cancer chemotherapeutic agents such as daunorubicin (Dauno) and vinblastine (VBL). Chemosensitization by EPO did not involve an increase in p53 activation, yet correlated with enhanced Bax/Bak-dependent mitochondrial membrane perturbation and caspase maturation. In vitro monotherapy with Dauno or VBL induced the degradation of IkappaBalpha, provoked the translocation of NF-kappaB p65/50 to the nucleus and stimulated the expression of an NF-kappaB-activatable reporter gene. All these signs of NF-kappaB activation were perturbed in the presence of EPO. Inhibition of JAK2, one of the receptor-proximal elements of EPO-mediated signal transduction, greatly diminished the EPO-mediated chemosensitization and NF-kappaB inhibition. EPO lost its death-facilitating effects in the presence of an NF-kappaB inhibitor, underscoring the cause-effect relationship between EPO-mediated chemosensitization and NF-kappaB inhibition. Altogether, these results suggest that, at least in a specific subset of tumors, EPO receptor agonists can prevent activation of the NF-kappaB pathway, thereby enhancing the propensity of EPO receptor-positive tumor cells to undergo apoptosis.
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PMID:Chemosensitization by erythropoietin through inhibition of the NF-kappaB rescue pathway. 1558 Feb 99

The ubiquitin-mediated degradation of hypoxia-inducible factor-alpha (HIF-alpha) by a von Hippel-Lindau tumor suppressor protein (pVHL) is mechanistically responsible for controlling gene expression due to oxygen availability. Germline mutations in the VHL gene cause dysregulation of HIF and induce an autosomal dominant cancer syndrome referred to as VHL disease. However, it is unclear whether HIF accumulation caused by VHL mutations is sufficient for tumorigenesis. Recently, we found that pVHL directly associates and positively regulates the tumor suppressor p53 by inhibiting Mdm2-mediated ubiquitination, and by subsequently recruiting p53-modifying enzymes. Moreover, VHL-deleted RCC cells showed attenuated apoptosis or abnormal cell-cycle arrest upon DNA damage, but became normal when pVHL was restored. Thus, pVHL appears to play a pivotal role in tumor suppression by participating actively as a component of p53 transactivation complex during DNA damage response.
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PMID:The positive regulation of p53 by the tumor suppressor VHL. 1696 13

The VHL (von Hippel-Lindau) tumour-suppressor gene is inactivated in VHL disease and in sporadic cases of CCRCC [clear-cell RCC (renal cell carcinoma)]. pVHL (VHL protein) functions as part of an E3 ubiquitin ligase complex that targets proteins for proteasomal degradation. The best-characterized substrate is HIF-alpha (hypoxia-inducible factor-alpha). Loss of pVHL and subsequent up-regulation of HIF target genes has been attributed to the highly vascular nature of these neoplasms. However, pVHL does not just function as the executioner of HIF-alpha. Additional functions of pVHL that may be important in preventing CCRCC tumorigenesis have been identified, including primary cilium maintenance, assembly of the extracellular matrix and roles in the stabilization of p53 and Jade-1 (gene for apoptosis and differentiation in epithelia). Current evidence indicates that pVHL probably requires additional co-operating signalling pathways for CCRCC initiation and tumorigenesis.
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PMID:Role of the VHL (von Hippel-Lindau) gene in renal cancer: a multifunctional tumour suppressor. 1848 84


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