Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There are at present disparate published results with regard to the relevance of the Bcl-2 gene family, levels of apoptosis, and cell proliferation in the development and progression of renal cell carcinoma (RCC). The present study analyses the inter-relationship between the expression of representatives of the anti-apoptotic (Bcl-2, Bcl-XL) or pro-apoptotic (Bax) Bcl-2 proteins, incidence of apoptosis, and mitosis in a selected small group of 22 graded RCCs that had paired normal renal tissue, or non-neoplastic tissue in the renal biopsy specimen. The cases were chosen to determine the feasibility of measuring these parameters as potential surrogate markers of progression or treatment failure of the cancers. The results showed that in approximately 50% of the RCCs, where Bcl-2 and/or Bcl-XL expression was high, apoptosis was not detected, and when expression of these proteins was low or not found, increased levels of apoptosis were seen. In most of the remaining 50% of samples, high levels of Bcl-XL but not Bcl-2 were negatively correlated with low levels of apoptosis (Bcl-XL: r = -0.437, P = 0.07 and Bcl-2: r = +0.560, P = 0.02). For the same group of samples, high Bax expression was found in association with apoptosis (r = +0.578, P = 0.02). A novel finding was an association between low expression of Bcl-2 and/or Bcl-XL in normal tissue and the level of expression of these proteins in the RCCs, an intrinsic variation that may be an individual patient factor. The results indicate that, in RCCs with increased expression of Bcl-2 and/or Bcl-XL, levels of apoptosis are minimal and these combined factors may assist in progression of the cancers and resistance to treatments.
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PMID:Apoptosis and expression of Bcl-2, Bcl-XL, and Bax in renal cell carcinomas. 1202 27

Previously, we showed that monensin, Na+ ionophore, potently inhibited the growth of acute myelogenous leukemia and lymphoma cells. Here, we demonstrate that monensin inhibited the proliferation of renal cell carcinoma cells with IC50 of about 2.5 micro M. Monensin induced a G1 or a G2-M phase arrest in these cells. When we examined the effects of this drug on ACHN cells, monensin decreased the levels of CDK2, CDK6, cdc2, cyclin A and cyclin B1 proteins. p21 and p27 proteins were increased by monensin. In addition, monensin markedly enhanced the binding of p21 with CDK2 and the binding of p27 with CDK6. Furthermore, the activities of CDK2- and CDK6-associated kinase were reduced in association with hypophosphorylation of Rb protein. Monensin also induced the apoptosis in several renal cell carcinoma cells. Apoptotic process of Caki-2 cells was associated with the changes of Bcl-2, Bcl-XL, caspase-9, caspase-3, caspase-7 proteins as well as mitochondria transmembrane potential (DeltaPsim) loss. Taken together, these results demonstrate for the first time that monensin inhibits the growth of renal cell carcinoma cells via cell cycle arrest or apoptosis.
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PMID:Monensin inhibits the growth of renal cell carcinoma cells via cell cycle arrest or apoptosis. 1263 79

It is now understood that the genetic plasticity of cancer cells can lead to alterations that confer selective growth advantages to the tumor, some of which play a role in immune escape. A number of mutations veiling tumor cells from host immune defenses have been well characterized but more recent studies suggest that a variety of tumors can also express products that are actually toxic for the immune effectors. A component of this tumor-induced T-cell death has been attributed to receptor-mediated apoptosis. Some tumors, however, synthesize soluble factors that mediate similar effects. In this regard, we previously showed that supernatants from explanted renal cell carcinoma (RCC) tumors sensitized normal T cells to activation induced cell death, and the responsible products had the features of gangliosides. We have also shown that renal tumor lines, including SK-RC-45, induce apoptosis of both Jurkat cells and normal T lymphocytes. Here, we used the ganglioside synthesis inhibitor PPPP to define the role of gangliosides in RCC cell line (SK-RC-45)-mediated T cell and Jurkat cell apoptosis and to elucidate the proapoptotic molecular events by which the glycosphingolipids produce their effects. The ganglioside-synthesizing SK-RC-45 line stimulated the TUNEL (terminal deoxynucleotidyl transferase-mediated nick end labeling) positivity of cocultured T cells by a mechanism that involved decreasing lymphocyte expression levels of Bcl-2 and Bcl-(XL), inducing cytochrome c release from their mitochondria and activating caspases 9 and 3. These proapoptotic events were partially or completely abrogated when tumor cells were pretreated with PPPP for 5 days before the SK-RC-45/T lymphocyte coincubation, a regimen that reduced tumor-associated ganglioside levels by 70-80%. Our results suggest that gangliosides may be key mediators of RCC-induced T-cell apoptosis and imply that they contribute to the T-cell dysfunction in the tumor microenvironment.
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PMID:Gangliosides expressed by the renal cell carcinoma cell line SK-RC-45 are involved in tumor-induced apoptosis of T cells. 1267 Sep 22

We investigated the in vitro effect of trichostatin (histone deacetylase inhibitor) on cell proliferation, cell cycle regulation and apoptosis in renal cell carcinoma cell lines. Trichostatin significantly inhibited the proliferation of all six cell lines examined in dose-dependent manner with IC50 of about 125-250 nM. Trichostatin (72-h incubation) induced a G1 phase arrest in ACHN, Caki-1, Caki-2 and Renca cell lines and a G2-M phase arrest in A498 cells. When we examined the effects of this drug on ACHN cells, trichostatin decreased the levels of CDK4, CDK6, cyclin D1 and cyclin A proteins. p27 protein was increased by trichostatin. In addition, trichostatin markedly enhanced the binding of p27 with CDK2 and CDK4. Furthermore, the activities of CDK2, CDK4- and CDK6-associated kinase were reduced and the lack of the CDK activity was paralleled by increased hypophosphorylation of Rb protein. Trichostatin also induced apoptosis in all the renal cell carcinoma cell lines. Apoptotic process of ACHN cells was associated with the changes of Bcl-2, caspase-9, caspase-3, caspase-7 proteins as well as mitochondria transmembrane potential (deltapsim) loss. Taken together, these results demonstrate that trichostatin inhibits the growth of renal cell carcinoma cells via cell cycle arrest or apoptosis.
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PMID:Trichostatin inhibits the growth of ACHN renal cell carcinoma cells via cell cycle arrest in association with p27, or apoptosis. 1268 81

At the present time, there is no reliable laboratory marker for the diagnosis and prognosis of clear cell renal cell carcinoma (RCC), while about 20% of small tumours detected by modern imaging techniques are benign and the clinical course is difficult to predict with considerable differences for the same stage and same grade. The molecular identification of clear cell RCC cells could satisfy these new requirements in the context of diagnosis of atypical or small renal tumours, allowing a more refined prognostic assessment, which is currently uncertain. Some of the antigens used for molecular diagnosis of clear cell RCC, such as cadherin-6, are present in the normal kidney, while others are newly formed antigens (TuM2PK, MN/CA9, CA12, calpain) or ectopic (PSMA, PSA, KLKI, cytokeratin 7 vimentin) or induce abnormal glycosylation (sialyl Lewis'X, galectins) indicating the malignant nature of the cells. The tumour's capacity for progression is related to dysregulations of the cycle (ras, Pax2, Tiam 1, waf/p21), division (tetracyclines, MIB1, PCNA, Nor Ag), apoptosis (bcl2, p53, CD95/Apo1), and the capacities for tissue invasion (proteases), disorganization (cadherin, catenins) or nidation (ICAM-1, CD44). Finally, chromosomal anomalies (mutations, translocations) also occur. MN/CA9, cadherin-6, vimentin, mucin 1 and DNA content are particularly useful for the diagnosis and/or prognosis of clear cell RCC. These markers can be analysed by extremely sensitive cytometric (flow cytometry, plate cytometry) or molecular methods (RT-PCR, in situ hybridization). These techniques lower the limit of detection of tumour cells in biological products (aspiration cytology, microbiopsy) and eventually in circulating blood. Proteomic and genomic methods (biochips) should considerably accelerate research in this field leading to the development of routine clinical applications.
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PMID:[Molecular and cytometric analysis of renal cell carcinoma cells. Concepts, techniques and prospects]. 1270 48

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

beta-Catenin and transcriptional factor TCF-4 (human T-cell factor-4) genes comprise the Wnt signal. The Wnt signal pathway plays an important role in malignant transformation. We hypothesize that the beta-catenin and TCF-4 gene and Wnt signal are important in the progression of renal cell carcinoma (RCC). To test this hypothesis, we investigated TCF-4 splicing isoforms, beta-catenin, and Wnt signal pathway (cyclin D1, c-myc, c-jun, and MMP7) in three RCC cell lines (A498, Caki-1, and Caki-2), 38 primary RCCs, and 29 normal kidney samples. We also analyzed the relationship between TCF-4 gene splicing isoforms, proliferation (proliferating cell nuclear antigen labeling index), and apoptosis [antiapoptotic factors (Bcl-2 and Bcl-x(L)), proapoptotic factors (Bak and Bax), and caspase-3] in RCC samples. In 38 RCC samples, four splicing isoforms of the TCF-4 gene were present in the region between exon 12 and exon 17. Thirty (79%) of 38 RCCs and all (100%) of the normal kidney samples showed mixed isoforms with both long and short reading frames in the COOH-terminal region, whereas the remaining 8 RCC samples showed only the long-form reading frame. Two COOH-terminal-binding protein sites were present only in the long-form reading frame. The eight RCCs that demonstrated only the long reading frame isoform showed early disease progression and poor prognosis. In these 8 RCC samples, down-regulation of cyclin D1, c-myc, c-jun, and MMP7 expression was observed at the mRNA level. In addition, a marked reduction of caspase-3 expression was also found at both the mRNA and the protein level. However, the beta-catenin gene was not overexpressed at the mRNA level and protein level, and mutation and deletion were not observed in exon 3. In these three renal cell lines, there was no significant difference in TCF-4 mRNA expression before and after 5-Aza-2'-deoxycytidine treatment, and there appeared to be no splicing isoforms in the region between exon 1 and exon 11. These findings suggest that alteration in beta-catenin is an infrequent event in RCC. In samples in which beta-catenin was not overexpressed, the target genes of Wnt signal were regulated through TCF-4 splicing isoforms. The imbalance between TCF-4 gene splicing isoforms with long and short reading frames is associated with RCC progression through the inhibition of the apoptotic pathway. We demonstrate for the first time that TCF-4 gene splicing isoforms and the Wnt signal pathway can induce progression of RCC by the inhibition of apoptosis and not by the induction of cell proliferation.
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PMID:The human T-cell factor-4 gene splicing isoforms, Wnt signal pathway, and apoptosis in renal cell carcinoma. 1279 77

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

The von Hippel-Lindau tumor suppressor protein (pVHL) suppresses tumor formation by binding the alpha subunits of hypoxia-inducible factors (HIFs) responsible for stimulating tumor angiogenesis and glycolysis, targeting them for ubiquitination and proteasomal destruction. Loss of pVHL leads to the development of sporadic renal cell carcinomas (RCCs). In the present study, we sought to determine whether engineered overexpression of pVHL in tumors other than RCC can inhibit tumor growth, either as a monotherapy, or in combination with antisense HIF-1alpha therapy. Intratumoral injection of subcutaneous EL-4 thymic lymphomas with an expression plasmid encoding pVHL resulted in the downregulation of HIF-1alpha and vascular endothelial growth factor (VEGF). There was a concomitant reduction in tumor angiogenesis and increased tumor cell apoptosis due in part to downregulation of Bcl-2 expression. VHL therapy resulted in the complete regression of small (0.1 cm diameter) tumors whereas, in contrast, large (0.4 cm diameter) EL-4 tumors were only slowed in their growth. Nevertheless, large tumors completely regressed in response to intratumoral injection of a combination of antisense HIF-1alpha and VHL plasmids. Combination therapy resulted in increased losses of HIF-1alpha, VEGF, and tumor blood vessels, and increased tumor cell apoptosis. These novel results suggest that synergistic therapies that simultaneously block the expression or function of HIF-1alpha, and enhance the expression or function of VHL may be beneficial in the treatment of cancer.
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PMID:Regression of solid tumors by engineered overexpression of von Hippel-Lindau tumor suppressor protein and antisense hypoxia-inducible factor-1alpha. 1459 81

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


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