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

Natural food products such as resveratrol have gained considerable attention as cancer chemopreventive agents. In the present study, we investigated the potential of resveratrol to overcome the resistance of tumour cells against TRAIL. While resveratrol enhanced TRAIL-induced apoptosis through G1 cell cycle arrest and survivin depletion, resveratrol failed to sensitise cells with high expression levels of Bcl-2 or FADD-DN. Interestingly, overexpression of Bcl-2 or FADD-DN did not interfere with resveratrol-mediated cell cycle arrest or survivin depletion, but blocked release of cytochrome c and Smac from mitochondria into the cytosol, enhanced caspase activation and apoptosis upon combined treatment with resveratrol and TRAIL indicating that overexpression of Bcl-2 or FADD-DN decoupled the effect of resveratrol on the cell cycle and apoptosis. Similarly, cell cycle arrest at G1 using the cell cycle specific inhibitor mimosine or downregulation of survivin expression by antisense oligonucleotides failed to enhance TRAIL-induced apoptosis in Bcl-2- or FADD-DN-transfected cells. Likewise, inhibition of caspase activity using the broad range caspase inhibitor zVAD.fmk did not interfere with resveratrol-mediated cell cycle arrest and survivin depletion, while blocking apoptosis upon combined treatment with resveratrol and TRAIL. Thus, resveratrol is a potent sensitiser for TRAIL in certain tumours. However, it may be ineffective in others, e.g. in tumours with enhanced Bcl-2 expression or defective death receptor signalling.
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PMID:Resveratrol-mediated sensitisation to TRAIL-induced apoptosis depends on death receptor and mitochondrial signalling. 1576 56

Indole-3-carbinol, found in Brassica species vegetables (such as cabbage, cauliflower, and brussels spouts), exhibits antitumor effects through poorly defined mechanisms. Because several genes that regulate apoptosis, proliferation, and metastasis are regulated by nuclear factor-kappaB (NF-kappaB), we postulated that indole-3-carbinol must mediate its activity through NF-kappaB modulation. We demonstrated that indole-3-carbinol suppressed constitutive NF-kappaB activation and activation induced by tumor necrosis factor (TNF), interleukin-1beta (IL-1beta), phorbol 12-myristate 13-acetate (PMA), lipopolysaccharide (LPS), and cigarette smoke; the suppression was not cell type specific, because activation was inhibited in myeloid, leukemia, and epithelial cells. This activation correlated with the sequential suppression of the IkappaBalpha kinase, IkappaBalpha phosphorylation, IkappaBalpha ubiquitination, IkappaBalpha degradation, p65 phosphorylation, p65 nuclear translocation, p65 acetylation, and NF-kappaB-dependent reporter gene expression. The NF-kappaB-regulated gene products cyclin D1, cyclooxygenase-2 (COX-2), matrix metalloproteinase-9 (MMP-9), survivin, inhibitor-of-apoptosis protein-1 (IAP1), IAP2, X chromosome-linked IAP (XIAP), Bcl-2, Bfl-1/A1, TNF receptor-associated factor-1 (TRAF1), and Fas-associated death domain protein-like interleukin-1beta-converting enzyme inhibitory protein (FLIP) were all down-regulated by indole-3-carbinol. This down-regulation led to the potentiation of apoptosis induced by cytokines and chemotherapeutic agents. Indole-3-carbinol suppressed constitutive NF-kappaB activation in mononuclear cells derived from bone marrow of acute myelogenous leukemia patients, and this correlated with inhibition of cell growth. Overall, our results indicated that indole-3-carbinol inhibits NF-kappaB and NF-kappaB-regulated gene expression and that this mechanism may provide the molecular basis for its ability to suppress tumorigenesis.
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PMID:Indole-3-carbinol suppresses NF-kappaB and IkappaBalpha kinase activation, causing inhibition of expression of NF-kappaB-regulated antiapoptotic and metastatic gene products and enhancement of apoptosis in myeloid and leukemia cells. 1581 58

The mitochondrial cell death pathway is known for its role in signaling apoptosis. Here, we describe a novel function for the mitochondrial cell death pathway in signaling initiation of differentiation in the developing lens. Most remarkably, we induced lens cell differentiation by short-term exposure of lens epithelial cells to the apoptogen staurosporine. Activation of apoptosis-related pathways induced lens epithelial cells to express differentiation-specific markers and to undergo morphogenetic changes that led to formation of the lens-like structures known as lentoids. The fact that multiple stages of differentiation are expressed at a single stage of development in the embryonic lens made it possible to precisely determine the timing of expression of proteins associated with the apoptotic pathway. We discovered that there was high expression in the lens equatorial epithelium (the region of the lens in which differentiation is initiated) of pro-apoptotic molecules such as Bax and Bcl-x(S) and release of cytochrome c from mitochondria. Furthermore, we found significant caspase-3-like activity in the equatorial epithelium, yet this activity was far lower than that associated with lens cell apoptosis. These apoptotic pathways are likely regulated by the concurrent expression of prosurvival molecules, including Bcl-2 and Bcl-x(L); phosphorylation of Bad; and high expression of inhibitor of apoptosis proteins chicken IAP1, IAP3, and survivin. This finding suggests that prosurvival pathways allow pro-apoptotic molecules to function as molecular switches in the differentiation process without tipping the balance toward apoptosis. We call this process apoptosis-related Bcl-2- and caspase-dependent (ABC) differentiation.
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PMID:The canonical intrinsic mitochondrial death pathway has a non-apoptotic role in signaling lens cell differentiation. 1582 55

Apoptosis, also known as programmed cell death, is regulated by a number of inhibitory or stimulatory factors. In addition to the pro- and anti-apoptotic Bcl-2 family proteins, there is also a family of inhibitors of apoptosis protein (IAP). Survivin, a member of this IAP family, is selectively upregulated in most tumours. The objective of the present study was, therefore, to investigate the protein and mRNA expression of survivin, as well as the methylation status of the CpG sites in exon 1 of the survivin gene for 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal-pouch squamous-cell carcinomas. Immunohistochemical analysis for protein expression, RT-PCR for mRNA expression, and a PCR-based methylation assay were performed on 26 samples of hamster buccal pouches. The total study population was assigned into either one experimental group (15-week DMBA treatment; n=13) or two control groups (untreated: n=6; mineral-oil treated n=7). Cytoplasmic staining of survivin protein and mRNA were detected in all of the hamster buccal-pouch tissue specimens treated with DMBA, whereas neither survivin protein nor survivin mRNA were noted for all of the untreated and mineral oil-treated hamster buccal-pouch tissue specimens. Furthermore, all the untreated and mineral-oil treated samples had a survivin-methylated allele, whereas the DMBA-treated cancerous tissues showed no evidence of survivin methylation. The results suggest that survivin may play an important role in DMBA-induced hamster buccal-pouch carcinomas, and that the gene expression may be modulated by an epigenetic mechanism.
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PMID:Survivin expression is regulated by an epigenetic mechanism for DMBA-induced hamster buccal-pouch squamous-cell carcinomas. 1584 53

1'-Acetoxychavicol acetate (ACA), extracted from rhizomes of the commonly used ethno-medicinal plant Languas galanga, has been found to suppress chemical- and virus-induced tumor initiation and promotion through a poorly understood mechanism. Because several genes that regulate cellular proliferation, carcinogenesis, metastasis, and survival are regulated by activation of the transcription factor NF-kappaB, we postulated that ACA might mediate its activity through modulation of NF-kappaB activation. For this report, we investigated the effect of ACA on NF-kappaB and NF-kappaB-regulated gene expression activated by various carcinogens. We found that ACA suppressed NF-kappaB activation induced by a wide variety of inflammatory and carcinogenic agents, including TNF, IL-1beta, PMA, LPS, H(2)O(2), doxorubicin, and cigarette smoke condensate. Suppression was not cell type specific, because both inducible and constitutive NF-kappaB activations were blocked by ACA. ACA did not interfere with the binding of NF-kappaB to the DNA, but, rather, inhibited IkappaBalpha kinase activation, IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, and subsequent p65 nuclear translocation. ACA also inhibited NF-kappaB-dependent reporter gene expression activated by TNF, TNFR1, TNFR-associated death domain protein, TNFR-associated factor-2, and IkappaBalpha kinase, but not that activated by p65. Consequently, ACA suppressed the expression of TNF-induced NF-kappaB-regulated proliferative (e.g., cyclin D1 and c-Myc), antiapoptotic (survivin, inhibitor of apoptosis protein-1 (IAP1), IAP2, X-chromosome-linked IAP, Bcl-2, Bcl-x(L), Bfl-1/A1, and FLIP), and metastatic (cyclooxygenase-2, ICAM-1, vascular endothelial growth factor, and matrix metalloprotease-9) gene products. ACA also enhanced the apoptosis induced by TNF and chemotherapeutic agents and suppressed invasion. Overall, our results indicate that ACA inhibits activation of NF-kappaB and NF-kappaB-regulated gene expression, which may explain the ability of ACA to enhance apoptosis and inhibit invasion.
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PMID:Identification of a novel blocker of I kappa B alpha kinase that enhances cellular apoptosis and inhibits cellular invasion through suppression of NF-kappa B-regulated gene products. 1590 86

Early stage laryngeal cancer can be effectively cured by radiotherapy or conservative laryngeal surgery. In the UK, radiotherapy is the preferred first line treatment. However, up to 25% of patients with T2 tumours will demonstrate locally persistent or recurrent disease at the original site, requiring salvage surgery to achieve a definitive cure. Patients experiencing treatment failure have a relatively poor prognosis. A retrospective analysis was conducted consisting of 124 patients with early stage (T1-T2, N0) laryngeal squamous cell carcinoma. In total, 62 patients who failed radiotherapy were matched for T stage, laryngeal subsite and smoking history to a group of 62 patients successfully cured by radiotherapy. Using immunohistochemistry the groups were compared for expression of apoptotic proteins: bcl-2, bcl-X(L), bax, bak and survivin. Radioresistant laryngeal cancer was associated with bcl-2 (P < 0.001) and bcl-X(L) (P = 0.005) expression and loss of bax expression (P = 0.012) in pretreatment biopsies. Bcl-2 has an accuracy of 71% in predicting radiotherapy outcome. The association between expression of bcl-2, bcl-X(L) and bax with radioresistant cancer suggests a potential mechanism by which cancer cells avoid the destructive effects of radiotherapy. Predicting radioresistance, using bcl-2, would allow the clinician to recommend conservative laryngeal surgery as an alternative first line treatment to radiotherapy.
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PMID:Bcl-2 expression predicts radiotherapy failure in laryngeal cancer. 1592 64

We found that bone morphogenetic protein (BMP) 7, a member of the BMP family, was strikingly up-regulated during the development of primary prostatic adenocarcinoma in the conditional Pten deletion mouse model. To determine the relevance of this finding to human prostate cancer, we examined the expression of BMPs and BMP receptors (BMPR) as well as the responsiveness to recombinant human BMP7 in a series of human prostate tumor cell lines. All prostatic cell lines tested expressed variable levels of BMP2, BMP4, and BMP7 and at least two of each type I and II BMPRs. In all cases, BMP7 induced Smad phosphorylation in a dose-dependent manner, with Smad5 activation clearly demonstrable. However, the biological responses to BMP7 were cell type specific. BPH-1, a cell line representing benign prostatic epithelial hyperplasia, was growth arrested at G1. In the bone metastasis-derived PC-3 prostate cancer cells, BMP7 induced epithelial-mesenchymal transdifferentiation with classic changes in morphology, motility, invasiveness, and molecular markers. Finally, BMP7 inhibited serum starvation-induced apoptosis in the LNCaP prostate cancer cell line and more remarkably in its bone metastatic variant C4-2B line. Each of the cell lines influenced by BMP7 was also responsive to BMP2 in a corresponding manner. The antiapoptotic activity of BMP7 in the LNCaP and C4-2B cell lines was not associated with a significant alteration in the levels of the proapoptotic protein Bax or the antiapoptotic proteins Bcl-2, Bcl-xl, and X-linked inhibitor of apoptosis. However, in C4-2B cells but not in LNCaP cells, a starvation-induced decrease in the level of survivin was counteracted by BMP7. Taken together, these findings suggest that BMPs are able to modulate the biological behavior of prostate tumor cells in diverse and cell type-specific manner and point to certain mechanisms by which these secreted signaling molecules may contribute to prostate cancer growth and metastasis.
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PMID:Diverse biological effect and Smad signaling of bone morphogenetic protein 7 in prostate tumor cells. 1599 52

In TNF-related apoptosis-inducing ligand (TRAIL)-resistant glioma cells, co-treatment with nontoxic doses of sodium butyrate and TRAIL resulted in a marked increase of TRAIL-induced apoptosis. This combined treatment was also cytotoxic to glioma cells overexpressing Bcl-2 or Bcl-xL, but not to normal human astrocytes, thus offering an attractive strategy for safely treating resistant gliomas. Cotreatment with sodium butyrate facilitated completion of proteolytic processing of procaspase-3 that was partially blocked by treatment with TRAIL alone. We also found that treatment with sodium butyrate significantly decreased the protein levels of survivin and X-linked inhibitor of apoptosis protein (XIAP), two major caspase inhibitors. Overexpression of survivin and XIAP attenuated sodium butyrate-stimulated TRAIL-induced apoptosis, suggesting its involvement in conferring TRAIL resistance to glioma cells. Furthermore, the kinase activities of Cdc2 and Cdk2 were significantly decreased following sodium butyrate treatment, accompanying downregulation of cyclin A and cyclin B, as well as upregulation of p21. Forced expression of Cdc2 plus cyclin B, but not Cdk2 plus cyclin A, attenuated sodium butyrate/TRAIL-induced apoptosis, overriding sodium butyrate-mediated downregulation of survivin and XIAP. Therefore, Cdc2-mediated downregulation of survivin and XIAP by sodium butyrate may contribute to the recovery of TRAIL sensitivity in glioma cells.
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PMID:Sodium butyrate sensitizes human glioma cells to TRAIL-mediated apoptosis through inhibition of Cdc2 and the subsequent downregulation of survivin and XIAP. 1600 42

Zerumbone found in subtropical ginger Zingiber zerumbet Smith exhibits antiproliferative and antiinflammatory activities but underlying molecular mechanisms are poorly understood. As several genes that regulate proliferation and apoptosis are regulated by nuclear factor (NF)-kappaB, we hypothesized that zerumbone mediates its activity through the modulation of NF-kappaB activation. We found that zerumbone suppressed NF-kappaB activation induced by tumor necrosis factor (TNF), okadaic acid, cigarette smoke condensate, phorbol myristate acetate, and H2O2 and that the suppression was not cell type specific. Interestingly, alpha-humulene, a structural analogue of zerumbone lacking the carbonyl group, was completely inactive. Besides being inducible, constitutively active NF-kappaB was also inhibited. NF-kappaB inhibition by zerumbone correlated with sequential suppression of the IkappaBalpha kinase activity, IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, p65 nuclear translocation, and p65 acylation. Zerumbone also inhibited the NF-kappaB-dependent reporter gene expression activated by TNF, TNFR1, TRADD, TRAF2, NIK, and IKK but not that activated by the p65 subunit of NF-kappaB. NF-kappaB-regulated gene products, such as cyclin D1, COX-2, MMP-9, ICAM-1, c-Myc, survivin, IAP1, IAP2, XIAP, Bcl-2, Bcl-xL, Bfl-1/A1, TRAF1 and FLIP, were all downregulated by zerumbone. This downregulation led to the potentiation of apoptosis induced by cytokines and chemotherapeutic agents. Zerumbone's inhibition of expression of these NF-kappaB-regulated genes also correlated with the suppression of TNF-induced invasion activity. Overall, our results indicated that zerumbone inhibits the activation of NF-kappaB and NF-kappaB-regulated gene expression induced by carcinogens and that this inhibition may provide a molecular basis for the prevention and treatment of cancer by zerumbone.
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PMID:Zerumbone abolishes NF-kappaB and IkappaBalpha kinase activation leading to suppression of antiapoptotic and metastatic gene expression, upregulation of apoptosis, and downregulation of invasion. 1600 45

Angiogenesis is one of essential components for the growth of neoplasms, including malignant gliomas. However, tumor vascularization is often poorly organized and marginally functional due to tumor structural abnormalities, inducing regional or temporal hypoxic conditions and nutritional shortages in tumor tissues. We investigated how during angiogenesis migrating endothelial cells survive in these hypoxic and reduced nutritional conditions. Human brain microvascular endothelial cells (HBMECs) underwent apoptosis and necrosis after serum withdrawal. This endothelial cell death was blocked by recombinant VEGF protein or the culture medium of U251 glioma cells exposed to hypoxia (H-CM). Hypoxic treatment increased vascular endothelial growth factor (VEGF) and tumor necrosis factor alpha (TNF-alpha) expression in U251 glioma cells. H-CM activated nuclear factor-kappaB (NFkappaB) protein and increased the gene expression of antiapoptotic factors including Bcl-2, Bcl-X(L), survivin and X-chromosome-linked inhibitor of apoptosis protein (XIAP) in endothelial cells. The survival activity of H-CM for endothelial cells was abolished by two kinds of VEGF inhibitors {Cyclopeptidic VEGF inhibitor and a VEGF receptor tyrosine kinase inhibitor (4-[(4'-chloro-2'-fluoro) phenylamino]-6, 7-dimethoxyquinazoline)} or NFkappaB inhibitors (ALLN and BAY 11-7082). These VEGF inhibitors did not block the activation of NFkappaB induced by H-CM in endothelial cells. On the contrary, TNF-alpha antagonist WP9QY enhanced the survival activity of H-CM for endothelial cells and blocked NFkappaB activation induced by H-CM under serum-starved conditions. Taken together, our data suggest that both the secretion of VEGF from glioma cells and activation of NFkappaB in endothelial cells induced by TNF-alpha are necessary for endothelial cell survival as they increase the expression of antiapoptotic genes in endothelial cells under conditions of serum starvation. These pathways may be one of the mechanisms by which angiogenesis is maintained in glioma tissues.
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PMID:Glioma cells under hypoxic conditions block the brain microvascular endothelial cell death induced by serum starvation. 1604 57


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