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)

The rate of tumor growth depends on the balance between proliferation and death of tumor cells. It is known that Bax, caspase-3, and p53 proteins are death-promoting factors, whereas Bcl-2 protein is a death antagonist. We immunohistochemically examined the expression of Bax and apoptosis-related proteins such as caspase-3, p53, and Bcl-2 in 76 patients with human esophageal squamous cell carcinoma (SCC) including dysplasia to determine the relationship of expression of each protein to tumor behavior and patients' prognosis. No significant relationships in immunopositivity were found among these proteins in SCCs. Cytoplasmic Bax expression was exhibited in 63 cases of SCCs (82.9%). The apoptotic index of caspase-3-positive lesions was significantly higher than that of caspase-3-negative lesions in both dysplasia and SCC (P =.016, P =.012). On the other hand, the apoptotic index (1.18%) was significantly correlated with Bax overexpression in dysplasia (P =.006), but not in SCC lesions (P =.129). The patients with Bax-positive SCCs were found to have a poor prognosis by the Kaplan-Meier method (P =.043). These findings suggested that Bax expressed in dysplasia may play a role as an apoptotic factor, but that it may be functionally inactive in some cancerous lesions and thus not contribute to suppression of the tumor progression in some cases of human esophageal SCCs.
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PMID:Expression of Bax and apoptosis-related proteins in human esophageal squamous cell carcinoma including dysplasia. 1150 32

Glioblastoma multiforme (WHO grade IV; GBM) is the most common primary brain tumor with a median survival of less than one year despite multimodal treatment regimens. However, a small subgroup of GBM patients has a better clinical outcome, with a small number of patients surviving several years. Apoptosis, a genetically determined program of cell suicide, may be induced as a consequence of critical DNA damage. However, due to defects in the signaling pathways, cancer cells may escape apoptosis, despite carrying irreversible DNA damage. In the present study, we have analyzed tumors of two age-matched, equally treated groups of GBM patients with different postoperative time to tumor progression (TTP), defined as 'short-term' for TTP of less than 6 months (n = 54), and 'long-term' for TTP of more than 12 months (n = 39) for alterations in apoptosis regulatory pathways: Mutations of the TP53 tumor suppressor gene and/or nuclear accumulation of its gene product p53, expression of Waf/p21, CD95 (Apo1/Fas), and Bcl-2. TP53 mutations were found in 12 out of 54 (22%) GBMs of short-term survivors and 8 out of 35 (23%) tumors of long-term survivors; the respective numbers for nuclear p53 protein accumulation were 12/53 (23%) and 10/37 (27%). Waf1/p21 expression was found in 13/53 (25%) tumors of short-term survivors and 9/35 (26%) GBMs of long-term survivors. The respective numbers for Bcl-2 expression were 25/42 (60%) and 22/36 (61%) and for CD95 (Apo1/Fas) expression 20/49 (41%) and 14/36 (39%) GBMs. The percentage of alterations in genes/proteins involved in the apoptotic pathway investigated here was virtually identical in the two groups of clinically different GBM patients. Thus, our data imply that none of these alterations investigated per se has a strong impact on the overall survival of GBM patients.
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PMID:TP53 gene mutations, nuclear p53 accumulation, expression of Waf/p21, Bcl-2, and CD95 (APO-1/Fas) proteins are not prognostic factors in de novo glioblastoma multiforme. 1151 57

Apoptosis is important for both tissue development and differentiation; its deregulation may contribute to tumourigenesis. In order to clarify the role of Bcl-2, an apoptosis-inhibiting protein, in pancreatic morphogenesis and tumour progression, its immunohistochemical expression was evaluated in 12 samples of fetal pancreas, in 10 samples of adult pancreas with ductal hyperplastic lesions, in 120 cases of primary pancreatic ductal adenocarcinoma, and in 43 synchronous metastatic lymph nodes. To evaluate the role of apoptosis in pancreatic cancer, p53 expression was also studied in tumour samples. Bcl-2 cytoplasmic acinar and ductal immunostaining was found in all fetal and adult tissue samples; ductal hyperplastic lesions were constantly negative. Thirty out of 120 (25%) tumours and 3 out of 43 (7%) lymph nodes expressed Bcl-2, whereas 67 out of 120 (56%) expressed nuclear p53. Well-differentiated tumours (G1) were more frequently Bcl-2-positive (p=0.002); furthermore, there was an inverse correlation between Bcl-2 and p53 expression in primary tumours (p=0.02). Neither Bcl-2 nor p53 influenced patients' prognosis, which was instead affected by N (p=0.02) and M (p<0.0001) status and stage of the disease (p=0.002). It is concluded that Bcl-2 regulates pancreatic morphogenesis and tissue homeostasis from early fetal to adult life and can be considered a phenotypic marker of normal exocrine pancreas. On the other hand, the lack of expression in preneoplastic lesions and the low positivity found in primary tumours and lymph node metastases suggest that Bcl-2 does not play a centralrole in pancreatic tumourigenesis and cancer progression.
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PMID:Bcl-2 expression in pancreas development and pancreatic cancer progression. 1152 52

pT1 G3 bladder carcinomas are heterogeneous with respect to tumor recurrence and progression. Whereas some urologists treat these carcinomas by repeated transurethral resections often followed by intravesical chemotherapy or BCG instillation, others recommend cystectomy after tumor recurrence or early cystectomy after the initial diagnosis. Our goal was to determine the prognostic value of p53, p21/WAF1, Bcl-2, Bax, Bak, and Ki-67 immunoreactivity in these tumors. There were 30 patients with a new histopathological diagnosis of pT1 G3 urothelial carcinoma based on a transurethral resection specimen. Representative sections of these specimens were examined for the above markers. All patients were followed up regularly and were classified as being tumor free or having tumor recurrence or progression. The mean follow-up period was 43 months (range: 8-102 months). Twenty-five patients underwent radical cystectomy and 7 of these (28%) suffered from tumor progression and died of bladder cancer. In 5 patients, surgery was limited to a transurethral resection and 4 of these patients developed superficial tumor recurrence. There was a significant difference in tumor-free survival between patients with p53-immunoreactive (mean: 30 months) and p53-negative tumors (mean: 82 months; p = 0.0341). Bcl-2 positivity was also associated with decreased tumor-free survival (p = 0.043). The other markers had no significant prognostic impact. We conclude that p53 and Bcl-2 immunoreactivity labels the most aggressive pT1 G3 bladder carcinomas.
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PMID:Prognostic value of p53, p21/WAF1, Bcl-2, Bax, Bak and Ki-67 immunoreactivity in pT1 G3 urothelial bladder carcinomas. 1155 64

Hypoxia is a common environmental stress. Particularly, the center of rapidly growing solid tumors is easily exposed to hypoxic conditions. Thus, tumor cell response to hypoxia plays an important role in tumor progression as well as tumor therapy. However, little is known about hypoxic effect on apoptotic cell death. To examine the effects of hypoxia on TRAIL-induced apoptosis, human lung carcinoma A549 cells were exposed to hypoxia and treated with TRAIL protein. Hypoxia significantly protected A549 cells from apoptosis induced by TRAIL. Western blotting analysis demonstrated that hypoxia increased expression of antiapoptotic proteins such as Bcl-2, Bcl-XL, and IAP family members. The increase of these antiapoptotic molecules is believed to play an hypoxia-mediated protective role in TRAIL-induced apoptosis. Our findings suggest that an increase of antiapoptotic proteins induced by hypoxia may regulate the therapeutic activity of TRAIL protein in cancer therapy.
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PMID:Hypoxia inhibition of apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). 1182 75

Pro- and anti-apoptotic members of the BCL-2 family play a central role in the implementation of apoptosis. Bax, a pro-apoptotic member of this family, has as such been considered as a potential tumor suppressor. Here, we have examined the expression of Bax in 55 patients with glioblastoma multiforme (GBM), the most common and aggressive form of brain tumors. We report on the existence of a new form of Bax, present in 24% of the patients, which we called Baxpsi. Baxpsi is a N-terminal truncated form of Bax which results from a partial deletion of the exon 1 of Bax gene. Baxpsi and the wild-type form, Baxalpha, are encoded by distinct mRNAs, both of which are present in normal tissues. Glial tumors express either Baxalpha or Baxpsi proteins, an apparent consequence of an exclusive transcription of the corresponding mRNAs. The latter feature could be partially linked to distinct methylation profiles of Bax gene in these tumors. The Baxpsi protein is preferentially localized to mitochondria and is a more powerful inducer of apoptosis than Baxalpha. Baxpsi tumors exhibit a slow proliferation in Swiss nude mice and this feature can be circumvented by the co-expression of the Bcl-2 transgene, the functional antagonist of Bax. More importantly, the expression of Baxpsi correlates with a longer survival in patients (18 months versus 10 months for Baxalpha patients). Thus, our results provide the first indication of a beneficial involvement of a variant of the pro-apoptotic protein Bax in tumor progression.
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PMID:The expression of a new variant of the pro-apoptotic molecule Bax, Baxpsi, is correlated with an increased survival of glioblastoma multiforme patients. 1191 83

Antiapoptotic oncoprotein Bcl-2 has extramitochondrial actions due to its localization on the endoplasmic reticulum (ER); however, the specific mechanisms of such actions remain unclear. Here we show that Bcl-2 overexpression in LNCaP prostate cancer epithelial cells results in downregulation of store-operated Ca(2+) current by decreasing the number of functional channels and inhibiting ER Ca(2+) uptake through a reduction in the expression of calreticulin and SERCA2b, two key proteins controlling ER Ca(2+) content. Furthermore, we demonstrate that Ca(2+) store depletion by itself is not sufficient to induce apoptosis in Bcl-2 overexpressing cells, and that sustained Ca(2+) entry via activated store-operated channels (SOCs) is required as well. Our data therefore suggest the pivotal role of SOCs in apoptosis and cancer progression.
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PMID:Bcl-2-dependent modulation of Ca(2+) homeostasis and store-operated channels in prostate cancer cells. 1208 75

Associated with the metastatic progression of epithelial tumors is the dynamic regulation of cadherins. Whereas E-cadherin is expressed in most epithelium and carcinomas, recent studies suggest that the up-regulation of other cadherin subtypes in carcinomas, such as N-cadherin, may function in cancer progression. We demonstrate that a signal transduction cascade links the N-cadherin.catenin adhesion complex to up-regulation of the anti-apoptotic protein Bcl-2. In suspension, aggregates of DU-145 cells, an E-cadherin expressing human prostate carcinoma line, survive loss of integrin-dependent adhesion by a different anti-apoptotic signaling pathway than the N-cadherin expressing lines PC3 and PC3N. N-cadherin intercellular adhesion mediates a 3.5-fold increase in Bcl-2 protein expression, whereas the level of the proapoptotic protein Bax remains constant. Only N-cadherin ligation in PC3 cells, which express both N-cadherin and E-cadherin, is sufficient to induce activation of Akt/protein kinase B. N-cadherin homophilic ligation initiates phosphatidylinositol 3-kinase-dependent activation of Akt resulting in Akt phosphorylation of Bad on serine 136. Following N-cadherin homophilic adhesion phosphatidylinositol 3-kinase was identified in immunoprecipitates of the N-cadherin.catenin complex. The recruitment of phosphatidylinositol 3-kinase to the adhesion complex is dependent on ligation of N-cadherin and an organized actin cytoskeleton because cytochalasin D blocks the recruitment. We propose that N-cadherin homophilic adhesion can initiate anti-apoptotic signaling, which enhances the Akt cell survival pathway in metastatic cancer.
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PMID:Signal transduction from N-cadherin increases Bcl-2. Regulation of the phosphatidylinositol 3-kinase/Akt pathway by homophilic adhesion and actin cytoskeletal organization. 1209 80

The main obstacle to improved survival of advanced prostate cancer is our failure to prevent its progression to its lethal and untreatable stage of androgen independence. New therapeutic strategies designed to prevent androgen-independent (AI) progression must be developed before significant impact on survival can be achieved. Characterization of changes in gene expression profiles after androgen ablation and during progression to androgen-independence suggest that the various therapies used to kill neoplastic cells may precipitate changes in gene expression that lead to the resistant phenotype. Castration-induced increases in antiapoptosis genes, Bcl-2 and clusterin, help create a resistant phenotype, while antisense oligonucleotides can inhibit these adaptive cell survival mechanisms and enhance both hormone and chemotherapy. Ongoing efforts are necessary to identify additional molecular pathways mediating AI progression and chemoresistance, since complexities of tumor heterogeneity and adaptability dictate that optimal control over tumor progression will require multi-target systemic therapies.
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PMID:Targeting anti-apoptotic genes upregulated by androgen withdrawal using antisense oligonucleotides to enhance androgen- and chemo-sensitivity in prostate cancer. 1209 75

Inactivation of p53 and expression of Bcl-2, frequently occurring during tumor progression, have different prognostic value: while inactivation of p53 is generally associated with unfavorable prognosis, expression of Bcl-2 often correlates with better clinical outcome and delays selection of metastatic variants of experimental tumors. To analyze the mechanisms underlying the "anti-progression" function of Bcl-2, we engineered tumor cell variants differing in their p53 status and Bcl-2 expression and compared their expansion in experimental tumors. Although neither p53 suppression nor Bcl-2-expression altered cell growth properties in vitro, both variants showed rapid accumulation in growing tumors in vivo, presumably due to their resistance to hypoxia. However, no expansion of p53-deficient variants occurred in the tumors formed by Bcl-2-overexpressing cells, indicating that p53 deficiency has no selective advantages in the Bcl-2-expressing environment. Importantly, expression of Bcl-2, unlike p53 suppression, did not lead to genomic instability as judged by the frequencies of gene amplification. Thus, acquisition of Bcl-2 expression is as advantageous for tumor cell growth in vivo as is p53 inactivation but does not affect genomic stability and creates the environment restrictive for the expansion of genetically unstable and potentially malignant p53-deficient cells, causing a delay in tumor progression and explaining the different prognostic value of Bcl-2 and p53.
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PMID:Apoptosis inhibitor as a suppressor of tumor progression: expression of Bcl-2 eliminates selective advantages for p53-deficient cells in the tumor. 1219 83


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