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 proto-oncogene product Ron is the receptor for macrophage stimulating protein, a scatter factor that stimulates cell proliferation, prevents apoptosis, and induces an invasive cell phenotype. We investigated the expression of Ron, Ki-67 (proliferation index), p53, and bcl-2 (proapoptotic and antiapoptotic proteins, respectively) in 50 renal tumors (19 clear cell carcinomas, 18 oncocytomas, 7 papillary cell carcinomas, 5 chromophobe cell carcinomas, and 1 carcinoma with sarcomatoid areas). In addition, we studied Ron in normal kidney and in the renal carcinoma cell line Caki-1. Immunostaining and Western blot showed Ron in normal kidney and in all oncocytomas but never in renal cell carcinomas or in Caki-1. In addition, Western blot showed that Ron was expressed in phosphorylated, i.e., active, form. Bcl-2 was strongly expressed in oncocytomas, whereas Ki-67 and p53 were much less expressed in oncocytomas than in carcinomas. These results indicate in Ron a marker that differentiates oncocytoma from the other renal epithelial tumors. We therefore think that Ron may prove to be a new tool for a sound and precise diagnosis of oncocytoma, a benign tumor that cannot always be distinguished from carcinomas at histologic examination. The overexpression of bcl-2, but not p53 in oncocytoma, suggests that the MSP/Ron system sustains the growth of oncocytoma by opposing apoptosis.
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PMID:The Ron proto-oncogene product is a phenotypic marker of renal oncocytoma. 1276 81

Bcl-2 antagonizes p53-induced apoptosis and may contribute to chemoresistance. In renal cell carcinoma (RCC), the role of bcl-2 is not well-defined, though its expression is reportedly low in primary tumors and lacks prognostic value. This study evaluates patterns of bcl-2 expression in high-risk (pT(3)) primary tumors and in matched patient metastases. Immunohistochemical analysis of bcl-2 was performed on 149 cases of conventional (clear cell) RCC (112 pT(3) primaries, 37 metastases). Paraffin-embedded tissues were obtained from nephrectomies and metastatic resections. Median follow up was 48 months in the entire cohort and 69 months in living patients. We evaluated associations between bcl-2 expression and tumor recurrence or patient survival with the Cox regression test, and used the t-test and Pearson correlation methods to evaluate bcl-2 expression in primary and metastatic cases. Bcl-2 expression was observed at a higher frequency in metastases (21/37 cases; 57%) compared to primary tumors (24/112 cases; 21%; P < 0.001). The percentage of cells stained was greater in metastases than primary tumors (P = 0.003). This finding was also noted when expression in metastatic cases was compared with matched primaries (P = 0.05). Bcl-2 expression did not predict disease-free (P = 0.30), disease-specific (P = 0.90), or overall (P = 0.51) survival. Most RCC primary tumors have low-to-absent levels of bcl-2 protein, whereas most RCC metastases display greater protein levels. Bcl-2 expression in primary tumors does not predict clinical outcome. However, expression of bcl-2 protein occurs at a high frequency in RCC metastases when compared to primary tumors. It may be reasonable to target RCC patients displaying altered bcl-2 levels for molecular therapies, such as anti-bcl2, should metastatic disease develop.
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PMID:Conventional (clear cell) renal carcinoma metastases have greater bcl-2 expression than high-risk primary tumors. 1281 Feb 3

A case of synchronous triple carcinomas arising in the kidney, bladder and prostate is reported. An 82-year-old man had gross hematuria. Urine cytology was positive and intravenous pyelography showed right hydronephrosis with a filling defect in the bladder. Computed tomography revealed a 4 cm mass in the bladder, enlarged prostate and 6 cm renal mass at the left kidney. Cystoscopy demonstrated a papillary broadbased tumor with some small satellite tumors in the bladder, and magnetic resonance imaging revealed muscle invasion of the bladder tumor. This patient underwent left radical nephrectomy and total cystoprostatectomy with ileal conduit urinary diversion as radical treatment. Histological diagnosis was renal cell carcinoma, transitional cell carcinoma of the bladder. Furthermore, well-differentiated adenocarcinoma was found incidentally in the prostate. Immunohistochemical staining with anti-p53 antibody for the three tumors showed positive staining only for the bladder cancer.
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PMID:[A case of synchronous triple primary carcinomas of the kidney, bladder and prostate]. 1282 53

TP53, a gene located on chromosome 17p13, encodes a nuclear protein (p53) involved in cell cycle regulation. This protein degrades in 20 minutes. However, the inactivated gene can produce a protein with a half-life 4-20 times longer than that of the wild type; it can be demonstrated by immunohistochemistry. Unfortunately, all the antibodies recognize both proteins, and the determination of a cutoff in the percentage of positive nuclei is required for the detection of cases with correlation of the TP53 mutation. In urologic tumors, p53 overexpression determination can be diagnostic help in low grade superficial bladder cancer, in cases of cystectomy and pN0, and in penile cancer without clinically involved lymph nodes. It does not seem useful in renal cell carcinoma or testicular germ cell tumors, and its utility is limited in prostate carcinoma.
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PMID:TP53 in urologic tumors. 1288 83

Papillary renal cell carcinomas are associated with chromosomal translocations involving the helix-loop-helix leucine-zipper region of the TFE3 gene on the X chromosome. These translocations lead to the expression of TFE3 chimeras of PRCC, RCC17, NonO and PSF (PTB-associated splicing factor). In this study, we explored the role of PSF-TFE3 fusion protein in mediating cell transformation. Unlike wild-type TFE3 or PSF, which are nuclear proteins, PSF-TFE3 is not a nuclear protein and is targeted to the endosomal compartment. Although PSF-TFE3 has no effect on the nuclear localization of wild-type PSF, it sequesters wild-type TFE3 as well as p53 in the extranuclear compartment leading to functionally null p53 and TFE3 cells. In UOK-145 papillary renal carcinoma cells, which endogenously express PSF-TFE3, siRNA complementary to the PSF-TFE3 fusion junction leads to a reduction in PSF-TFE3 and redistribution of endogenous TFE3 and p53 from the cytoplasmic compartment to the nucleus. Our results indicate that PSF-TFE3 acts through a novel mechanism, and exports TFE3, p53 and possibly other factors from the nucleus to the cytoplasm for degradation leading to the transformed phenotype. Thus, PSF-TFE3 is a promising target for the treatment for a subset of renal cell carcinomas.
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PMID:PSF-TFE3 oncoprotein in papillary renal cell carcinoma inactivates TFE3 and p53 through cytoplasmic sequestration. 1290 86

A metastatic renal cell carcinoma (RCC) tumor model xenograft that expresses the targetable, membrane-bound tumor-associated antigen carbonic anhydrase type 9 (CA IX) is described. The xenograft, established from a high-grade type-2 chromophil RCC (cRCC), has been serially transplanted in immune compromised mice, in which it grows orthotopically under the renal capsule, doubling its size every 9 weeks and sending metastases to the lung and liver at approximately 20 weeks. Tumors were capable of being imaged using a micro-PET (micro-positron emission tomograph) with an 18-fluorodeoxyglucose (18-FDG) tracer. Subsequent xenograft generations have conserved immunohistochemical and ultrastructural properties typical for malignant renal epithelium-derived neoplasia (vimentin+, CK-19+, CA IX+ with hypoxia-inducible factor (HIF)-1 alpha constitutive expression) and have demonstrated extensive proliferation, lack of apoptosis, severe genetic alterations, and molecular expression alterations; transforming growth factor beta 1 (TGF-beta 1), hepatocyte growth factor (HGF), proto-oncogene (c-met), matrix metalloproteinase (MMP)-1, and vascular endothelial growth factor (VEGF) C and D were overexpressed, whereas human epidermal growth factor receptor (HER)-2, MMP-2 and MMP-9, VEGF-R3, p53, and p27 were severely down-regulated, suggesting a proangiogenic environment, local invasiveness, and facilitated lymphatic metastasis. Altogether, LABAZ1 provides a relevant and flexible model to study the biology of cRCC, the role of CA IX in RCC tumorigenesis, progression, and metastasis, and a platform for testing new targeted therapeutic strategies.
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PMID:LABAZ1: A metastatic tumor model for renal cell carcinoma expressing the carbonic anhydrase type 9 tumor antigen. 1294 20

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

Previously, we reported that Bcl-2 was frequently expressed in renal cell carcinoma (RCC) specimens, but p53 mutation was a rare event. However, it was unclear whether Bcl-2 positivity was associated with the clinicopathological characteristics and prognosis in RCC. Therefore, we investigated the expression of Bcl-2 protein and its roles in 101 RCC specimens. In addition, the proliferation index (PI), apoptotic index (AI), caspase-3 and p53 expression were examined. The immunohistochemical method was applied for Bcl-2, caspase-3 and p53 protein expression. To investigate the proliferation activity and apoptosis of tumour cells, PI and AI were calculated based on Ki-67 and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL)-positive cells, respectively. Bcl-2 expression was detected in 72 out of 101 (71.3%) specimens. Bcl-2 positivity was inversely correlated with PI (P<0.0001) and AI (P=0.0074). Furthermore, Bcl-2 positivity was significantly correlated with better survival (P=0.0014), and was associated with lower stage (P=0.0301) and grade (P=0.0020). In RCC, frequent Bcl-2 expression was correlated with favourable character without higher PI and AI. Thus, Bcl-2 expression might be applied as a novel predictor of better prognosis in RCC patients.
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PMID:Impact of frequent Bcl-2 expression on better prognosis in renal cell carcinoma patients. 1471 Feb 30

HIF-1 (hypoxia-inducible factor-1), a heterodimeric transcription factor comprising HIF-1alpha and HIF-1beta subunits, serves as a key regulator of metabolic adaptation to hypoxia. HIF-1 activity largely increases during hypoxia by attenuating pVHL (von Hippel-Lindau protein)-dependent ubiquitination and subsequent 26 S-proteasomal degradation of HIF-1alpha. Besides HIF-1, the transcription factor and tumour suppressor p53 accumulates and is activated under conditions of prolonged/severe hypoxia. Recently, the interaction between p53 and HIF-1alpha was reported to evoke HIF-1alpha degradation. Destruction of HIF-1alpha by p53 was corroborated in the present study by using pVHL-deficient RCC4 (renal carcinoma) cells, supporting the notion of a pVHL-independent degradation process. In addition, low p53 expression repressed HIF-1 transactivation without affecting HIF-1alpha protein amount. Establishing that p53-evoked inhibition of HIF-1 reporter activity was relieved upon co-transfection of p300 suggested competition between p53 and HIF-1 for limiting amounts of the shared co-activator p300. This assumption was confirmed by showing competitive binding of in vitro transcription/translation-generated p53 and HIF-1alpha to the CH1 domain of p300 in vitro. We conclude that low p53 expression attenuates HIF-1 transactivation by competing for p300, whereas high p53 expression destroys the HIF-1alpha protein and thereby eliminates HIF-1 reporter activity. Thus once p53 becomes activated under conditions of severe hypoxia/anoxia, it contributes to terminating HIF-1 responses.
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PMID:p300 relieves p53-evoked transcriptional repression of hypoxia-inducible factor-1 (HIF-1). 1499 92

Renal cell carcinoma (RCC) rarely acquires mutations in p53 tumor suppressor gene, suggesting that p53 signaling in this tumor type might be repressed by some other mechanism. In fact, all four RCC-derived cell lines we tested maintained wild-type p53 but were not capable of transactivating p53-responsive reporters and endogenous p53-responsive genes. p53 protein in RCC showed normal response to genotoxic stress, including accumulation, nuclear translocation, and activation of specific DNA binding. Functional and expression analysis of Mdm2, MdmX, and Arf showed lack of involvement of these p53 regulators in the observed defect of p53 function in RCC. However, activation of p53-mediated transactivation could be achieved by extremely high levels of p53 attained by lentivirus vector-driven transduction, suggesting the involvement of a dominant inhibitor in repression of p53-dependent transactivation in RCC. Consistently, p53 inactivation prevailed in the hybrids of RCC cells with the cells possessing fully functional p53. Remarkably, cells of normal kidney epithelium also caused partial p53 repression in cell fusion experiments, suggesting that RCC-specific p53 repression may be based on an unknown dominant mechanism also acting in normal kidney tissue.
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PMID:p53 pathway in renal cell carcinoma is repressed by a dominant mechanism. 1502 29


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