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)

Bax is a homologue of Bcl-2 that promotes apoptosis. Bax protein levels were assessed by immunohistochemical methods in primary tumors derived from 119 women with metastatic breast cancer. These patients had received combination chemotherapy either with a once a month dosage schedule or in 4 weekly divided doses. The BAX immunostaining results were retrospectively compared with overall survival, time to tumor progression (TTP), and response, as well as several laboratory markers. Normal breast epithelium and in situ carcinomas immunostained positively for Bax. Marked reductions in Bax immunostaining were observed in 40 (34%) of 119 evaluable tumors. Reduced Bax correlated with shorter overall survival (median, 8.1 versus 15.7 months; P = 0.04), faster TTP (median, 2.0 versus 6.3 months; P = 0.009), and failure to respond (complete response, partial responses; 6% versus 42%, P = 0.01) in the subgroup of patients who received divided dose therapy. Reduced Bax immunostaining was not significant in the monthly dose group. When the two groups were combined, however, reduced Bax was significantly correlated in univariate analysis with failure to respond (21 versus 43% achieving complete response or partial response; P = 0.02), faster TTP (median, 3.7 versus 9.0 months; P = 0.02), and shorter survival (median, 10.7 versus 17.1 months; P = 0.04). Bax immunostaining was not significantly correlated with tumor histology, S-phase fraction, aneuploidy, p53 HER2, or cathepsin D, but was positively associated with Bcl-2 (P = 0.005). In multivariate analysis (Bax, tumor grade, and treatment group), reduced Bax was strongly associated with faster TTP (P approximately equal to 0.009) and shorter survival (P approximately equal to 0.001). Although highly preliminary, the finding suggest that loss of Bax immunostaining represents a novel prognostic indicator of poor response to chemotherapy and shorter survival in women with metastatic breast cancer, and raise the possibility that the subgroup of women with Bax-negative tumors may benefit from more aggressive therapy.
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PMID:Reduced expression of proapoptotic gene BAX is associated with poor response rates to combination chemotherapy and shorter survival in women with metastatic breast adenocarcinoma. 767 Dec 62

Overexpression of HER2 in estrogen receptor (ER)-positive human breast tumors has been associated with resistance to endocrine therapy. Here we investigated the effects of HER2 on expression of apoptotic pathways and modulation of tamoxifen-induced apoptosis in ER-positive MCF-7 breast cancer cells. We report that HER2 overexpression in MCF-7 cells is accompanied by up-regulation of antiapoptotic Bcl-2 and Bcl-XL proteins and suppression of tamoxifen-induced apoptosis. In addition, human tumor cell lines that are both ER positive and overexpress HER2 also express enhanced levels of Bcl-2 compared to cells that are either ER positive or overexpress HER2 alone. Our findings suggest that possible deregulation of antiapoptotic Bcl-2 and Bcl-XL may be associated with the enhanced survival of HER2-overexpressing and ER-positive breast cancer cells treated with antiestrogens.
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PMID:Overexpression of HER2 modulates bcl-2, bcl-XL, and tamoxifen-induced apoptosis in human MCF-7 breast cancer cells. 981 90

In patients with non-small cell lung cancer (NSCLC), tumor expression of P21-Ras, HER2, P53, and Bcl-2 has been reported as independent predictors of prognosis. However, the prognostic information carried by these proteins has usually been determined separately, and their potential interaction has not been taken into account. We conducted immunostaining for P21-Ras, HER2, P53 and Bcl-2 on 238 cases of NSCLC in a Korean population with 203 squamous cell carcinomas, and 35 adenocarcinomas. P21-Ras, HER2, P53 or Bcl-2 was expressed at high levels in 54.6, 42.0, 18.1 and 71.8% of the NSCLC studied, respectively. A total of 59 tumors (24.8%) expressed only one protein, while 70 (29.4%) expressed two, 59 (24.8) expressed three, and 17 tumors (7.1%) expressed all four proteins. Univariate analysis testing the association of marker expression with survival found Bcl-2 expression to be significantly associated with a poor prognosis, as well as the co-expression of Bcl-2 + HER2, Bcl-2 + HER2 + P53, and Bcl-2 + HER2 + P53 + P21-ras with an increasing hazard ratio. By multivariate analysis controlling for age, tumor stage and tumor type, only the combination of Bcl-2 + HER2 expression was an independent marker of poor prognosis (hazard ratio = 1.91, P = 0.003). Thus, a prospective analysis of the co-expression of Bcl-2 + HER2 in NSCLC patients may identify patients with a poor prognosis who may benefit from more aggressive therapy.
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PMID:The interactive effect of Ras, HER2, P53 and Bcl-2 expression in predicting the survival of non-small cell lung cancer patients. 1004 71

The molecular changes associated with the transition of melanoma cells from radial growth phase (RGP) to vertical growth phase [(VGP), metastatic phenotype] are not very well defined. We previously demonstrated that expression of the cell-surface adhesion molecule MCAM/MUC18 correlates directly with the metastatic potential of human melanoma cells. In addition, the progression of human melanoma towards the metastatic phenotype is associated with loss of expression of the tyrosine-kinase receptor c-KIT. In this review, I will summarize our recent studies demonstrating that the expression of both genes is regulated by the AP-2 transcription factor. Moreover, we have observed a loss of AP-2 expression in metastatic melanoma cells. Re-expression of AP-2 in the highly metastatic A375SM cells decreased their tumorigenicity and inhibited their metastatic potential in nude mice. MCAM/MUC18 mRNA and protein expression was significantly down-regulated while c-KIT expression was up-regulated in the AP-2-transfected cells. To further investigate the role of AP-2 in the progression of human melanoma, we attempted to inactivate AP-2 in primary cutaneous melanoma by using a dominant-negative AP-2, or the AP-2B gene. Expression of AP-2B in SB-2 cells augmented their tumorigenicity in nude mice, and upregulated MMP-2 expression and activity. As AP-2 also regulates other genes that are involved in the progression of human melanoma such as E-cadherin, p21/WAF-1, HER2/neu, Bcl-2, FAS/APO-1, IGF-R-1, VEGF and the thrombin receptor (PAR-1), we therefore propose that loss of AP-2 is a crucial event in the development of malignant melanoma. In addition, the transition of melanoma cells from RGP to VGP is also associated with over-expression of the transcription factors CREB and ATF-1. The notion that the balance between AP-2 and CREB/ATF-1 expression determines the progression of melanoma cells towards the metastatic phenotype will be discussed.
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PMID:Gene regulation in melanoma progression by the AP-2 transcription factor. 1131 Jul 95

One of the major challenges of early-stage breast cancer is to select the adjuvant therapy that ensures the most benefits and the least harm for the patient. The definition of accurate predictive factors is therefore of paramount importance. So far the choice of adjuvant therapy has been based on the number of affected lymph nodes and the hormone receptor status of the patient. This paper evaluates the use of other tumor-related markers as predictive factors for adjuvant therapy. These include HER2, p53 and Bcl-2, cathepsin B, p27, proliferating cell nuclear antigen (PCNA), cyclin D, Ki-67, and vascular endothelial growth factor (VEGF).
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PMID:Predictive factor for the response to adjuvant therapy with emphasis in breast cancer. 1173 86

Heregulins are a group of growth factors that play diverse and critical roles in the signaling network of the human epidermal growth factor receptor (HER or EGFR) superfamily. Our earlier studies have shown that recombinant heregulinbeta1 (HRG) induces apoptosis in SKBr3 breast cancer cells that overexpress HER2. Here we report molecular mechanisms of HRG-induced apoptosis. HRG treatment of SKBr3 cells for 72 h decreased the level of Bcl-2 protein. HRG treatment led to degradation of poly (ADP-ribose) polymerase (PARP) and activated both caspase-9 and caspase-7. No significant activation of caspase-3, -6, or -8 was detected. Expression of exogenous caspase-7 by adenovirus-caspase-7 (Ad-casp-7) in SKBr3 cells resulted in apoptosis, which mimicked the effect of HRG treatment. Expression of exogenous caspase-7 had no impact on Bcl-2 expression, but promoted PARP degradation. Two highly selective inhibitors of protein kinase C (PKC), GF109203X (GF) and Ro318425 (Ro), significantly enhanced HRG-induced apoptosis as determined by flow cytometric analysis and DNA fragmentation assay. Accordingly, the PKC inhibitor GF further decreased the level of Bcl-2 protein and further degraded PARP in HRG-treated cells. Assay of PKC activity indicated that HRG activated PKC in SKBr3 cells, predominantly affecting the PKCalpha isoform. To confirm which PKC isoform(s) mediated potentiation of HRG-induced apoptosis, the profile of PKC isoforms was measured in SKBr3 cells. Five PKC isoforms, PKCalpha, PKCiota, PKCzeta, PKClambda, and PKCdelta as well as their receptors (RACK1) were expressed in this cell line. Treatment with PKC inhibitors GF and Ro decreased protein levels of both PKCalpha and PKCdelta at 24 h. PKCalpha levels were still depressed at 72 h. GF and Ro had little effect on the expression of other PKC isoforms. An inhibitor of classical PKC isoforms (Go6976) enhanced HRG-induced apoptosis, whereas the PKCdelta selective inhibitor rottlerin did not. As PKCalpha was the only classical isoform expressed in SKBr3 cells, the effect of Go6976 on HRG-induced apoptosis largely related to inhibition of PKCalpha. Constitutive expression of wild-type PKCalpha attenuated the apoptosis produced by HRG and GF. Consequently, HRG-induced apoptosis in SKBr3 cells appeared to involve down-regulation of Bcl-2 protein, activation of caspase-9 and caspase-7, and degradation of PARP. Inhibition of PKC function enhanced HRG-induced apoptosis, leading to synergistic down-regulation of Bcl-2 expression. Impairment of the PKCalpha isoform alone was sufficient to potentiate HRG-induced apoptosis.
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PMID:Heregulin-induced apoptosis is mediated by down-regulation of Bcl-2 and activation of caspase-7 and is potentiated by impairment of protein kinase C alpha activity. 1178 40

This study assesses the potential value of the tumor markers p53, HER2, and Bcl-2 in predicting the clinical response to doxorubicin and paclitaxel as single agents in the treatment of metastatic breast cancer. The primary tumors of 114 patients in the European Organization for Research and Treatment of Cancer 10923 trial were assessed by immunohistochemistry using monoclonal antibodies; the results were correlated with clinical response to therapy. HER2 was positive in 24% of patients, p53 was positive in 25% of patients, and Bcl-2 was positive in 49% of patients. There was no correlation between the expression of any of the markers and the clinical response to either agent. Although methodologically limited, this study does not support the use of p53, HER2, or Bcl-2 to assist the selection of anthracycline versus taxane in metastatic breast cancer.
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PMID:A study of the value of p53, HER2, and Bcl-2 in the prediction of response to doxorubicin and paclitaxel as single agents in metastatic breast cancer: a companion study to EORTC 10923. 1189 48

In the multistep progressive pathogenesis of human breast cancer, comedo ductal carcinoma in situ (DCIS) represents a preinvasive precursor lesion for therapy resistant invasive cancer. Human tissue derived cell culture models exhibiting molecular similarities to clinical DCIS facilitate an important preclinical mechanistic approach for evaluation of preventive efficacy of natural and synthetic chemopreventive compounds. Natural phytochemicals present in fresh fruits, vegetables and grain products are likely to offer protection against cancer. The clinical efficacy of these natural phytochemicals, however, depends on extrapolation, and is therefore equivocal. The present study determined whether the natural soy isoflavone genistein (GEN) inhibited aberrant proliferation in 184-B5/HER cells (a model for human comedo DCIS) and identified possible mechanisms responsible for its efficacy. Human reduction mammoplasty derived HER-2/neu oncogene expressing preneoplastic 184-B5/HER cells represented the experimental system. Flow cytometry and cellular epifluorescence based assays were utilized to quantitate the alterations in cell cycle progression, cellular apoptosis, and in the status of cell cycle regulatory and apoptosis-associated gene product expression. The 184-B5/HER cells exhibited specific immunofluorescence to p185HER, p53, EGFR, but not to ERalpha, thus resembling comedo DCIS. Treatment of 184-B5/HER cells with GEN resulted in a dose-dependent decrease in the viable cell population, increase in the G0/G1:S + G2/M ratio and enhancement of sub G0/G1 (apoptotic population). Exposure to the maximum cytostatic 10 microM dose of GEN down-regulated HER-2/neu mediated signal transduction as evidenced by a 73.9% decrease (p=0.001) in p185HER specific, and a 89.8% decrease (p=0.001) in phosphotyrosine specific immunofluorescence. The increase in G0/G1:S + G2/M ratio in response to the treatment with 10 microM GEN was associated with a 85.5% decrease (p=0.001) in immunoreactivity to PCNA and a 128.6% increase (p=0.004) in immunoreactivity to the cyclin dependent kinase inhibitor p16INK4. The induction of apoptosis by GEN was associated with a 52.8% decrease (p=0.001) in the immunoreactivity to antiapoptotic Bcl-2 and with a 195.9% (p=0.001) increase in the immunoreactivity to proapoptotic Bax. Thus, preventive efficacy of GEN in HER-2/neu+/ER- 184-B5/HER cells may be due to its ability to down-regulate HER-2/neu mediated signal transduction, increase the expression of the cyclin dependent kinase inhibitor p16INK4, and induce Bcl-2 dependent apoptosis. These data provide evidence that GEN may be a potential chemopreventive lead compound for human comedo DCIS. The 184-B5/HER cells, may therefore, provide a high throughput mechanistic bioassay to identify new chemopreventive agents for human breast cancer.
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PMID:Soy isoflavone genistein modulates cell cycle progression and induces apoptosis in HER-2/neu oncogene expressing human breast epithelial cells. 1223 20

Biomarker analysis and evaluation in oncology is the product of a number of processes (including managerial, technical and interpretation steps) which need to be monitored and controlled to prevent and correct errors and guarantee a satisfactory level of quality. Several biomarkers have recently moved to clinical validation studies and successively to clinical practice without any definition of standard procedures and/or quality control (QC) schemes necessary to guarantee the reproducibility of the laboratory information. In Italy several national scientific societies and single researchers have activated -- often on a pilot level -- specific external quality assessment protocols, thereby potentially jeopardizing the clinical reality even further. In view of the seriousness of the problem, in 1998 the Italian Ministry of Health sponsored a National Survey Project to coordinate and standardize the procedures and to develop QC programs for the analysis of cancer biomarkers of potential clinical relevance. Twelve QC programs focused on biomarkers and concerning morphological, immunohistochemical, biochemical, molecular, and immunoenzymatic assays were coordinated and implemented. Specifically, external QC programs for the analytical phase of immunohistochemical p53, Bcl-2, c-erb-2/neu/HER2, and microvessel density determination, of morphological evaluation of tumor differentiation grade, and of molecular p53 analysis were activated for the first time within the project. Several hundreds of Italian laboratories took part in these QC programs, the results of which are available on the web site of the Network (www.cqlaboncologico.it). Financial support from the Italian Government and the National Research Council (CNR) will guarantee the pursuit of activities that will be extended to new biomarkers, to preanalytical phases of the assays, and to revision of the criteria of clinical usefulness for evaluating the cost/benefit ratio.
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PMID:Quality control for biomarker determination in oncology: the experience of the Italian Network for Quality Assessment of Tumor Biomarkers (INQAT). 1240 63

Inherited mutations of the BRCA1 gene predispose to breast, ovarian, and other cancers. The role of the BRCA1 gene in the maintenance of chromosomal integrity is linked to a number of biological properties of its protein product, including transcriptional regulation. In the present study, we have used suppression subtractive hybridisation (SSH) to identify genes induced by BRCA1 by comparing control MCF7 breast carcinoma cells (driver) with MCF7 cells ectopically expressing BRCA1 (tester) and generated a forward subtracted cDNA library. We screened 500 putative positive clones from this library. Two hundred and ten of these clones were positive by differential screening with forward and reverse subtracted probes and the 65 cDNA clones which showed more than fivefold increase were selected for sequencing analysis. We clustered 46 different genes that share high homology with sequences in the GenBank/EMBL databases. Among these, 30 were genes whose function had been previously identified while the remaining 16 clones were genes with unknown functions. Of particular interest, BRCA1 gene induces the expression of genes encoding DNA repair proteins RAD21 and MSH2, ERBB2/HER2 interacting protein ERBIN, meningioma-associated protein MAC30, and a candidate ovarian tumour-suppressor OVCA1. Northern and Western blot analyses confirmed that the expression of these five genes are up-regulated following BRCA1 overexpression in MCF7 and UBR60-bcl2 cells. This is the first study reporting a set of BRCA1-induced genes in breast carcinoma cells by the SSH technique. We suggest that some known genes identified in this study may provide new insights into the tumour-suppressor function of BRCA1.
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PMID:Identification of genes induced by BRCA1 in breast cancer cells. 1247 Jun 55


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