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)

Prognosis of primary melanoma is presently based on morphological parameters, mainly tumor thickness. However, more reliable prognostic markers are needed that allow a better stratification of patients, especially with regard to therapeutic options. Here, a retrospective study was performed on patients with primary superficial-spreading melanoma (SSM, n=44) or nodular melanoma (n=16) of 1.5-4 mm thickness. Thirty patients had survived the follow-up of 10 years, whereas the other 30 patients developed metastases. Tumor sections were analyzed by immunohistochemistry for the expression of regulators of the cell cycle (p21; retinoblastoma protein (pRb)), of the intrinsic or extrinsic proapoptotic pathways (p53; murine double minute gene 2 protein; tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-R1/DR4; TRAIL-R2/DR5) and of Bcl-2-related proteins (Bcl-2, Mcl-1, Bax, Bak, Bok), which regulate the common mitochondrial apoptotic pathway. In SSM, decrease of Bax and Bak was significantly correlated with a poor prognosis: high Bax was associated with 10-year survival rates of 68%, whereas low Bax resulted in only 26% survival, and high Bak was associated with 10-year survival rates of 62%, whereas low Bak resulted in only 10% survival. Regulators of apoptosis may therefore candidate for independent prognostic markers for primary melanomas. The study underlines the particular role of the mitochondrial apoptosis pathway and of proapoptotic Bcl-2-related proteins for melanoma progression.
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PMID:Loss of proapoptotic Bcl-2-related multidomain proteins in primary melanomas is associated with poor prognosis. 1670 69

TNF-related apoptosis-inducing ligand (TRAIL) is a promising cancer therapy that preferentially induces apoptosis in cancer cells. However, many neoplasms are resistant to TRAIL by mechanisms that are poorly understood. Here we demonstrated that human prostate cancer cells, but not normal prostate cells, are dramatically sensitized to TRAIL-induced apoptosis and caspase activation by quercetin. Quercetin, a ubiquitous bioactive plant flavonoid, has been shown to inhibit the proliferation of cancer cells. We have shown that quercetin can potentiate TRAIL-induced apoptotic death. Human prostate adenocarcinoma DU-145 and LNCaP cells were treated with various concentrations of TRAIL (10-200 ng/ml) and/or quercetin (10-200 microM) for 4 h. Quercetin, which caused no cytotoxicity by itself, promoted TRAIL-induced apoptosis. The TRAIL-mediated activation of caspase, and PARP (poly(ADP-ribose) polymerase) cleavage were both enhanced by quercetin. Western blot analysis showed that combined treatment with TRAIL and quercetin did not change the levels of TRAIL receptors (death receptors DR4 and DR5, and DcR2 (decoy receptor 2)) or anti-apoptotic proteins (FLICE-inhibitory protein (FLIP), inhibitor of apoptosis (IAP), and Bcl-2). However, quercetin promoted the dephosphorylation of Akt. Quercetin-induced potent inhibition of Akt phosphorylation. Taken together, the present studies suggest that quercetin enhances TRAIL-induced cytotoxicity by activating caspases and inhibiting phosphorylation of Akt.
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PMID:TRAIL apoptosis is enhanced by quercetin through Akt dephosphorylation. 1703 54

We established TRAIL-resistant MDA-231/TR cells from MDA-231 parent cells to understand the mechanism of TRAIL resistance in breast cancer cells. The selected TRAIL-resistant cells were cross-resistant to TNF-alpha/cycloheximide but remained sensitive to DNA-damage drugs such as oxaliplatin and etoposide. The expression levels of death receptors (DR4 and DR5), FADD, cIAP1, cIAP2, and Bcl-2 family were not changed in TRAIL-treated both cells. Significant down-regulation of XIAP and cFLIP was occurred after TRAIL treatment in MDA-231 cells whereas their levels were sustained in MDA-231/TR cells. TRAIL-mediated activation of ERK and JNK were also observed in parent MDA-231 cells but not in MDA-231/TR cells. However, TRAIL-resistant cells showed constitutive activation state after treatment with TRAIL. Pretreatment with PD98059 or transfection of MKK1-DN (dominant negative) expression vector attenuated TRAIL resistance in MDA-231/TR cells. Our findings provide the evidence that the sustained expression level of cFLIP(L) and XIAP protein and constitutive ERK activation may lead to acquired TRAIL resistance in breast cancer cells.
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PMID:Acquired TRAIL resistance in human breast cancer cells are caused by the sustained cFLIP(L) and XIAP protein levels and ERK activation. 1709 66

In general, oral squamous cell carcinoma (OSCC) cells are relatively resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis during culture in vitro. Here, we studied the role of phosphatidylinositol 3-kinase (PI 3-K)/Akt in survival and apoptosis of these cells. The PI 3-K inhibitors wortmannin and LY294002 markedly suppressed phosphorylation of Akt and accelerated TRAIL-mediated apoptosis in OSCC cells. Addition of TRAIL to PI 3-K inhibitor-treated cells resulted in caspase-8 activation and loss of mitochondrial membrane potential. Furthermore, inhibitors of caspase-3, -8 and -9 reduced the accelerative effect of PI 3-K inhibitors on TRAIL-mediated apoptosis. These results suggest that the pro-apoptotic effect of PI 3-K inhibitors on TRAIL-mediated apoptosis may contribute to both the extrinsic and intrinsic pathways. Although PI 3-K inhibitors did not affect expression of the TRAIL receptors DR4 and DR5, we observed a marked reduction in expression of cellular FLICE-inhibitory protein (c-FLIP), Bcl-2, cellular inhibitor of apoptosis protein-1 (cIAP-1) and X-linked IAP (XIAP), whereas Bax was up-regulated and no significant difference was observed in expression of Bcl-xL, Bak or cIAP-2. Therefore, the PI 3-K/Akt signaling pathway provides partial regulation of TRAIL-mediated apoptosis in OSCC cells via modulation of c-FLIP, Bcl-2, Bax, cIAP-1 and XIAP expression. These results suggest that PI 3-K inhibitors may represent a novel strategy for overcoming resistance to TRAIL-mediated apoptosis in OSCC cells.
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PMID:Enhanced susceptibility to tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in oral squamous cell carcinoma cells treated with phosphatidylinositol 3-kinase inhibitors. 1739 18

Resveratrol, a polyphenol found in numerous plant species, including mulberries, peanuts and grapes, has shown to possess chemopreventive properties against several cancers, and cardiovascular diseases. Recently, resveratrol has been shown to have positive effects on age longevity, lipid levels and a preventative quality against certain cancers and viral infections. Resveratrol induces apoptosis by up-regulating the expression of Bax, Bak, PUMA, Noxa, Bim, p53, TRAIL, TRAIL-R1/DR4 and TRAIL-R2/DR5 and simultaneously down-regulating the expression of Bcl-2, Bcl-XL, Mcl-1 and survivin. Resveratrol causes growth arrest at G1 and G1/S phases of cell cycle by inducing the expression of CDK inhibitors p21/WAF1/CIP1 and p27/KIP1. Resveratrol has also been shown to reduce inflammation via inhibition of prostaglandin production, cyclooxygenase-2 activity, and nuclear factor-kappaB activity. Modulation of cell signaling pathway by resveratrol explains its diverse bioactivities related with human health. Resveratrol also potentiates the apoptotic effects of cytokines, chemotherapeutic agents and gamma-radiation. Pharmacokinetic and pharmacodynamic studies demonstrated that the main target organs of resveratrol are liver and kidney, and it is metabolized by hydroxylation, glucuronidation, sulfation and hydrogenation. As a chemoprevention agent, resveratrol has been shown to inhibit tumor initiation, promotion, and progression. There is growing evidence that resveratrol can prevent or delay the onset of various cancers, heart diseases, ischemic and chemically induced injuries, pathological inflammation and viral infections. This review summarizes the molecular mechanisms of resveratrol and its clinical benefits for human diseases.
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PMID:Chemoprevention by resveratrol: molecular mechanisms and therapeutic potential. 1756 14

A triterpenediol (TPD) comprising of isomeric mixture of 3alpha, 24-dihydroxyurs-12-ene and 3alpha, 24-dihydroxyolean-12-ene from Boswellia serrata induces apoptosis in cancer cells. An attempt was made in this study to investigate the mechanism of cell death by TPD in human leukemia HL-60 cells. It inhibited cell proliferation with IC50 approximately 12 microg/ml and produced apoptosis as measured by various biological end points e.g. increased sub-G0 DNA fraction, DNA ladder formation, enhanced AnnexinV-FITC binding of the cells. Further, initial events involved massive reactive oxygen species (ROS) and nitric oxide (NO) formation, which were significantly inhibited by their respective inhibitors. Persistent high levels of NO and ROS caused Bcl-2 cleavage and translocation of Bax to mitochondria, which lead to loss of mitochondrial membrane potential (Deltapsim) and release of cytochrome c, AIF, Smac/DIABLO to the cytosol. These events were associated with decreased expression of survivin and ICAD with attendant activation of caspases leading to PARP cleavage. Furthermore, TPD up regulated the expression of cell death receptors DR4 and TNF-R1 level, leading to caspase-8 activation. These studies thus demonstrate that TPD produces oxidative stress in cancer cells that triggers self-demise by ROS and NO regulated activation of both the intrinsic and extrinsic signaling cascades.
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PMID:A triterpenediol from Boswellia serrata induces apoptosis through both the intrinsic and extrinsic apoptotic pathways in human leukemia HL-60 cells. 1763 81

Although resveratrol, an active ingredient derived from grapes and red wine, possesses chemopreventive properties against several cancers, the molecular mechanisms by which it inhibits cell growth and induces apoptosis have not been clearly understood. Here, we examined the molecular mechanisms of resveratrol and its interactive effects with TRAIL on apoptosis in prostate cancer PC-3 and DU-145 cells. Resveratrol inhibited cell viability and colony formation, and induced apoptosis in prostate cancer cells. Resveratrol downregulated the expression of Bcl-2, Bcl-X(L) and survivin and upregulated the expression of Bax, Bak, PUMA, Noxa, and Bim, and death receptors (TRAIL-R1/DR4 and TRAIL-R2/DR5). Treatment of prostate cancer cells with resveratrol resulted in generation of reactive oxygen species (ROS), translocation of Bax to mitochondria and subsequent drop in mitochondrial membrane potential, release of mitochondrial proteins (cytochrome c, Smac/DIABLO, and AIF) to cytosol, activation of effector caspase-3 and caspase-9, and induction of apoptosis. Resveratrol-induced ROS production, caspase-3 activity and apoptosis were inhibited by N-acetylcysteine. Bax was a major proapoptotic gene mediating the effects of resveratrol as Bax siRNA inhibited resveratrol-induced apoptosis. Resveratrol enhanced the apoptosis-inducing potential of TRAIL, and these effects were inhibited by either dominant negative FADD or caspase-8 siRNA. The combination of resveratrol and TRAIL enhanced the mitochondrial dysfunctions during apoptosis. These properties of resveratrol strongly suggest that it could be used either alone or in combination with TRAIL for the prevention and/or treatment of prostate cancer.
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PMID:Molecular mechanisms of resveratrol (3,4,5-trihydroxy-trans-stilbene) and its interaction with TNF-related apoptosis inducing ligand (TRAIL) in androgen-insensitive prostate cancer cells. 1763 62

TRAIL ligand induces selectively apoptosis in tumor cells by binding to two death receptors (DR4 and DR5) and holds promise as a potential therapeutic agent against cancer. While it has been known for long time that TRAIL receptors are commonly expressed in wide variety of normal tissues, it is not well understood why TRAIL kills tumor cells but leaves normal cells unharmed. The prototypic oncogene c-Myc promotes the cell cycle and simultaneously primes activation of the Bcl-2 family controlled mitochondria apoptosis pathway. A striking reflection of the c-Myc-dependent apoptotic sensitization is the dramatic c-Myc-induced vulnerability of cells to TRAIL and other death receptor ligands. Here we summarize the recent findings regarding the death mechanisms of TRAIL/TRAIL receptor system and the connection of c-Myc to the mitochondrial apoptosis pathway, focusing on our work that couples c-Myc via Bak to the TRAIL death receptor pathway. Finally, we present a mitochondria-priming model to explain how c-Myc-Bak interaction amplifies the TRAIL-induced caspase 8-Bid pathway to induce full-blown apoptosis. We discuss the implications of these findings for understanding the selective cytotoxicity of TRAIL and for the therapeutic exploitation of the death receptor pathway.
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PMID:c-Myc blazing a trail of death: coupling of the mitochondrial and death receptor apoptosis pathways by c-Myc. 1791 84

The major aim of this study was to develop novel therapeutic approaches to potentiate and reactivate apoptosis induced by TNF-Related Apoptosis Inducing Ligand (TRAIL) in malignant glioma. Analysis of five glioma cell lines (U87, U251, U373, MZ-54 and MZ-18) indicated that only two of the cell lines were sensitive to apoptosis induced by TRAIL alone. TRAIL resistance was not correlated to expression levels of the death receptors DR4 and DR5 or the decoy receptors DcR1 and DcR2, suggesting that it was mediated by inactivation of TRAIL-induced downstream signalling. Activation of the BH3 only protein Bid and subsequent activation of the mitochondrial apoptosis pathway are known to play a pivotal role in TRAIL-induced apoptosis. Since this process is blocked by overexpression of anti-apoptotic Bcl-2 family members, we analyzed the therapeutic potential of BH3 mimetics in potentiating TRAIL-induced apoptosis. Treatment with TRAIL in combination with the specific Bcl-2 inhibitor HA14-1 and the Bcl-2/Bcl-xL inhibitor BH3I-2' potently enhanced apoptosis in TRAIL-sensitive U87 cells in a dose-dependent fashion. TRAIL-induced apoptosis was significantly reactivated by HA14-1 and BH3I-2' in one (U343) and two (MZ-54 and MZ-18) of three investigated TRAIL-insensitive cell lines, respectively. Knockdown of the anti-apoptotic Bcl-2 family member Mcl-1 by RNA interference had no additional effect on apoptosis induced by TRAIL and HA14-1 in U87 and U343 cells. Our data indicate that Bcl-2 and Bcl-xL play fundamental roles in TRAIL resistance of malignant glioma and suggest that using TRAIL or agonistic TRAIL receptor antibodies in combination with BH3 mimetics may represent a promising approach to reactivate apoptosis in therapy-resistant high grade gliomas.
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PMID:Pharmacological inhibition of Bcl-2 family members reactivates TRAIL-induced apoptosis in malignant glioma. 1792 59

The tumor suppressor protein p53 restricts proliferation in response to DNA damage or the deregulation of mitogenic oncogenes, by leading to the induction of various cell cycle checkpoints, apoptosis or cellular senescence. Consequently, p53 mutations increase cell proliferation and survival and in some settings promote genomic instability and resistance to certain anti-cancer drugs. It is very important to identify chemotherapeutic agents that activate in a p53-independent manner for the development of treatments for p53-deficient tumors. Pectenotoxin-2 (PTX-2), isolated from marine sponges has been reported to display significant cytotoxicity to p53-deficient cancer cell lines. In this study, we compared the anti-cancer activity of PTX-2 in order to further test the status of p53 using two well-known hepatocarcinoma cell lines, p53-deficient Hep3B and p53-wild-type HepG2. MTT assay indicated that Hep3B cells were highly susceptible, whereas HepG2 cells were more resistant to this compound which was connected with the induction of apoptotic cell death in p53-deficient Hep3B cells, though not in HepG2 cells. The apoptosis induced by PTX-2 in Hep3B cells was associated with the down-regulation of anti-apoptotic Bcl-2 members (Bcl-2 and Bcl-xL) and IAP family proteins, the up-regulation of pro-apoptotic Bax protein and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-receptor 1/receptor 2 (DR4/DR5) and mitochondrial dysfunction. PTX-2 activated caspases (caspase-3, -8 and -9) and the blockade of caspase-3 activity by the caspase-3 inhibitor prevented the PTX-2-induced apoptosis in Hep3B cells. Additionally, the transcription factor early growth response-1 (Egr-1) gene was transcriptionally activated and the levels of non-steroidal anti-inflammatory drugs (NSAID)-activated gene-1 (NAG-1) protein were also elevated in PTX-2-treated Hep3B cells. Although further studies are needed to prove that an increased expression of Egr-1 by PTX-2 directly leads to NAG-1 induction and then apoptosis induction in p53-deficient Hep3B cells, the results of this study suggest that PTX-2 may be a good candidate for the development of a potential anti-tumorigenic agent in p53-deficient tumors.
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PMID:Induction of apoptosis by pectenotoxin-2 is mediated with the induction of DR4/DR5, Egr-1 and NAG-1, activation of caspases and modulation of the Bcl-2 family in p53-deficient Hep3B hepatocellular carcinoma cells. 1820 2


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