Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Statins are a class of low molecular weight drugs that inhibit the rate-limiting enzyme of the mevalonate pathway 3-hydroxy-3-methylglutaryl-CoA reductase. Statins have been approved and effectively used to control hypercholesterolemia in clinical setting. Recent study showed statin's antitumor activity and suggested a potential role for prevention of human cancers. In this study, we did cell viability, DNA fragmentation, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assays to evaluate the action of statins on prostate cancer cells and used Western blotting and RhoA activation assay to investigate the underlying molecular mechanism of action. Our data showed that lovastatin and simvastatin effectively decreased cell viability in three prostate cancer cell lines (PC3, DU145, and LnCap) by inducing apoptosis and cell growth arrest at G(1) phase. Both lovastatin and simvastatin induced activation of caspase-8, caspase-3, and, to a lesser extent, caspase-9. Both statins suppressed expression of Rb, phosphorylated Rb, cyclin D1, cyclin D3, CDK4, and CDK6, but induced p21 and p27 expression in prostate cancer cells. Furthermore, lovastatin and simvastatin suppressed RhoA activation and c-JUN expression, but not cyclooxygenase-2 expression. Our data showed that the antitumor activity of statins is due to induction of apoptosis and cell growth arrest. The underlying molecular mechanism of statin's action is mediated through inactivation of RhoA, which in turn induces caspase enzymatic activity and/or G(1) cell cycle. Future studies should focus on examining statins and other apoptosis-inducing drugs (e.g., cyclooxygenase-2 inhibitors or curcumin) together to assess their efficacy in prevention of prostate cancer.
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PMID:Statin induces apoptosis and cell growth arrest in prostate cancer cells. 1819 14

Acetyl-keto-beta-boswellic acid (AKBA), a triterpenoid isolated from Boswellia carterri Birdw and Boswellia serrata, has been found to inhibit tumor cell growth and to induce apoptosis. The apoptotic effects and the mechanisms of action of AKBA were studied in LNCaP and PC-3 human prostate cancer cells. AKBA induced apoptosis in both cell lines at concentrations above 10 microg/mL. AKBA-induced apoptosis was correlated with the activation of caspase-3 and caspase-8 as well as with poly(ADP)ribose polymerase (PARP) cleavage. The activation of caspase-8 was correlated with increased levels of death receptor (DR) 5 but not of Fas or DR4. AKBA-induced apoptosis, caspase-8 activation, and PARP cleavage were inhibited by knocking down DR5 using a small hairpin RNA. AKBA treatment increased the levels of CAAT/enhancer binding protein homologous protein (CHOP) and activated a DR5 promoter reporter but did not activate a DR5 promoter reporter with the mutant CHOP binding site. These results suggest that AKBA induces apoptosis in prostate cancer cells through a DR5-mediated pathway, which probably involves the induced expression of CHOP.
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PMID:Acetyl-keto-beta-boswellic acid induces apoptosis through a death receptor 5-mediated pathway in prostate cancer cells. 1828 94

Androgen withdrawal induces the regression of human prostate cancers, but such cancers eventually become androgen-independent and metastasize. Thus, deciphering the mechanism of androgen withdrawal-induced apoptosis is critical to designing new therapies for prostate cancer. Previously, we showed that in the rat, castration-induced apoptosis is accompanied by a reduction in the expression of the apical caspase inhibitor FLICE-like inhibitory protein (FLIP). To test the functional role of FLIP in inhibiting prostate epithelial cell apoptosis, we employed the rat prostate epithelial cell line NRP-152, which differentiates to a secretory phenotype in a low-mitogen medium and then undergoes apoptosis following the addition of transforming growth factor beta1 (TGFbeta1), mimicking androgen withdrawal-induced apoptosis. FLIP levels decline with TGFbeta1 treatment, suggesting that apoptosis is mediated by caspase-8 and indeed the caspase inhibitor crmA blocks TGFbeta1-induced apoptosis. Small interfering RNA-mediated knockdown of FLIP recapitulates and enhances TGFbeta1-induced cell death. NRP-152 cells stably transfected with constitutively expressed FLIP were refractory to TGFbeta1-induced apoptosis. TGFbeta1-induced caspase-3 activity is proportional to the level of cell death and inversely proportional to the level of FLIP expression in various clones. Moreover, neither caspase-3 nor PARP is cleaved in clones expressing high levels of FLIP. Furthermore, insulin, which inhibits differentiation, increases FLIP and inhibits TGFbeta-induced death in a FLIP-dependent manner. Although neither Fas-Fc, sTNFRII-Fc, nor DR5-Fc blocked TGFbeta1-induced cell death, there is a significant increase in tumor necrosis factor mRNA following TGFbeta stimulation, suggesting both an unexpected role for tumor necrosis factor in this model system and the possibility that FLIP blocks another unknown caspase-dependent mediator of apoptosis.
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PMID:FLICE-like inhibitory protein blocks transforming growth factor beta 1-induced caspase activation and apoptosis in prostate epithelial cells. 1831 84

Thiosulfinates, a substance of Allium tuberosum L., is a known folk medicine that has been extensively used in diet to treat diseases. In the present study, we have evaluated the effect of thiosulfinates from Allium tumberosum L. on proliferation of metastasis (DU145) and primary malignant tumor (RC-58T/h/SA#4)-derived human prostate cancer cells. Thiosulfinates decrease viable cell numbers in a dose- and time-dependent manner and induce apoptosis. The apoptosis induced by thiosulfinates is associated with the activation of initiator caspase-8, and -9, and the effector caspase-3. Thiosulfinates stimulated Bid cleavage, indicating that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. Thiosulfinates decreased the expression of the anti-apoptotic protein Bcl-2, and increased the expression of the pro-apoptotic protein Bax. Thiosulfinates also increased the expression of AIF, a caspase-independent mitochondrial apoptosis factor, in RC-58T/h/#4 cells and induced DNA fragmentation and chromatin condensation. These results indicate that thiosulfinates from Allium tuberosum L. inhibit cell proliferation by inducing apoptosis in RC-58T/h/#4 cells which may be mediated via both caspase-dependent and caspase-independent pathways.
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PMID:Induction of apoptosis by thiosulfinates in primary human prostate cancer cells. 1836 Jul 14

Combined treatment with quercetin and TRAIL induced cytotoxicity and enhanced annexin V staining and poly (ADP-ribose) polymerase (PARP) cleavage in human prostate cancer cell lines DU-145 and PC-3. These indicators of apoptosis resulted from the activation of caspase-8, -9, and -3. Although the expression levels of FLIPs, cIAP1, cIAP2, and the Bcl-2 family were not changed in quercetin-treated cells, significant downregulation of survivin occurred. Knockdown survivin by siRNA significantly increased TRAIL-induced apoptosis. We hypothesized that quercetin-induced activation of MAPK (ERK, p38, JNK) is responsible for downregulation of survivin gene expression. To test this hypothesis, we selectively inhibited MAPK during treatment with quercetin. Our data demonstrated that inhibitor of ERK (PD98059), but not p38 MAPK (SB203580) or JNK (SP600125), significantly maintained the intracellular level of survivin during treatment with quercetin. Interestingly, PD98059 also prevented quercetin-induced deacetylation of histone H3. Data from survivin promoter activity assay suggest that the Sp1 transcription factor binds to the survivin promoter region and quercetin inhibits its binding activity through deacetylation of histone H3. Quercetin-induced activation of the ERK-MSK1 signal transduction pathway may be responsible for deacetylation of histone H3. Taken together, our findings suggest that quercetin enhances TRAIL induced apoptosis by inhibition of survivin expression, through ERK-MSK1-mediated deacetylation of H3.
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PMID:Quercetin augments TRAIL-induced apoptotic death: involvement of the ERK signal transduction pathway. 1837 72

Neochamaejasmin A ( 1), a biflavonoid isolated from the roots of a traditional Chinese medicine, Stellera chamaejasme L., was shown to inhibit cellular (3)H-thymidine incorporation (IC 50 12.5 microg/mL) and subsequent proliferation of human prostate cancer LNCaP cells. Treatment of LNCaP cells with low doses of 1 (< or =6.25 microg/mL) suppressed DNA-binding activities of the transcription factors NFkappaB and AP-1 to the promoter of cyclin D and also inhibited expression of the cell cycle regulatory proteins cyclin D, proliferating cell nuclear antigen, and nucleolin, thus arresting cells in G 1 phase of the cell cycle. A lengthy exposure with higher doses of 1 (> or =12.5 microg/mL) revealed the production of reactive oxygen species, dissipation of the mitochondrial membrane potential, up-regulation of cyclin-dependent kinase inhibitor p21, and induction of cell apoptosis. An aggregation of Fas-procaspase 8-procaspase 3 and p21-procaspase 3 proteins by coimmunoprecipitation, immunoblotting analysis, and MALDI-mass spectrometry indicated the involvement of Fas and p21 in 1-mediated cytotoxicity, and pretreatment of cells with antisense FasL oligonucleotides partially abolished apoptosis. Thus, 1 blocked cell cycle progression at the G 1 phase by activating the p21 protein and ultimately promoting the Fas-caspase 8-caspase 3 apoptotic machinery.
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PMID:Involvement of p21 and FasL in induction of cell cycle arrest and apoptosis by neochamaejasmin A in human prostate LNCaP cancer cells. 1838 Apr 77

Synthetic triterpenoids 2-cyano-3, 12-dioxooleana-1, 9-(11)-dien-28-oic acid (CDDO) and CDDO-Me (CDDO-methyl ester) have entered clinical trials for cancer. We determined that CDDO analogues at submicromolar concentrations induce apoptosis of cultured prostate cancer cell lines, LNCaP, ALVA31, Du145, PC3, and PPC1, with lethal dose 50% approximately 1 micromol/L for CDDO-Me and an imidazole analogue (CDDO-Im). These compounds induced apoptosis of prostate cancer cells as characterized by cleavage of caspase-3, caspase-7, caspase-8, caspase-9, caspase-10, BID, and poly(ADP)ribose polymerase and by dependence on caspase activity. Moreover, triterpenoid-induced cell death was abolished by caspase-8-targeting small interfering (si) RNA. To explore the mechanism(s) involved in caspase-8 activation, we examined cell surface expression of death receptor (DR)4 and DR5 after triterpenoid treatment. Cell surface DR4 and DR5 expression was significantly up-regulated by CDDO or CDDO-Im but not by CDDO-Me. DR4 and DR5 knockdown with siRNA significantly inhibited apoptosis induced by CDDO and CDDO-Im but had no effect on CDDO-Me-induced killing, suggesting that CDDO and CDDO-Im induce apoptosis by a different mechanism than CDDO-Me. In addition to activating the caspase-8-dependent extrinsic apoptosis pathway, we observed that Bcl-X(L) overexpression inhibited triterpenoid-mediated killing of prostate cancer cell line Du145, suggesting that the intrinsic pathway (via mitochondria) also participates in triterpenoid-mediated killing. In vivo antitumor activity of CDDO-Me was shown using a Du145 tumor xenograft model in nude rats. Altogether, these findings suggest CDDO and related synthetic triterpenoids should be further evaluated as potential novel therapeutics for hormone refractory prostate cancers.
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PMID:Apoptotic activity and mechanism of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic-acid and related synthetic triterpenoids in prostate cancer. 1841 62

It has been reported that Breast Cancer Susceptibility gene-1 & 2 (BRCA1 & 2 are potential molecular targets for chemoprevention by isoflavone genistein (4' 5, 7-trihydroxy isoflavone), in breast and prostate cancer cells. It is also known that BRCA1 has inhibitory activity on estrogen receptor-alpha and genistein's action on cells is mainly through modulation of estrogen receptor activity. The action of genistein with respect to BRCA1 status in ovarian cancer cells has not been reported so far. Therefore in this study, we analyzed the action of genistein on BRCA1 antisense blocked (AS4) and unblocked (NEO) BG-1 ovarian cancer cells. We found that genistein induced comparable cytotoxic effect in both AS4 and NEO cells, but through different pathways. We found that genistein induces caspase 8 dependent apoptotic pathway in NEO cells. Genistein inhibits estrogen receptor-alpha and activates BARD1 in BRCA1 blocked cells and induces estrogen receptor-beta and FAS in presence of BRCA1. It can be concluded that even though there is no difference in the extent of cell death or apoptosis, the molecular mechanism of action of genistein in inducing apoptosis is different in BRCA1 blocked and unblocked cells. This could partially explain the beneficial effects of genistein in both wild type and mutated BRCA1 estrogen receptor positive tumors.
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PMID:Genistein induces apoptosis in ovarian cancer cells via different molecular pathways depending on Breast Cancer Susceptibility gene-1 (BRCA1) status. 1851 88

One of the major obstacles in curing prostate cancer is the development of drug resistance. It is not only imperative to discover the molecular basis of resistance but also to find therapeutic agents that can disrupt the resistant pathways. Tumor necrosis factor TNF-related apoptosis-inducing ligand TRAIL-like ligands or agonist TRAIL-receptor monoclonal antibodies have entered phase I and II clinical trials with a very limited cytotoxic profile when used systemically in a variety of cancers. Therefore, TRAIL-receptor agonists are new proapoptotic pharmaceutical agents with great potential as new cancer therapeutic agents. Although many cancer cells undergo TRAIL-mediated apoptosis, some are resistant to TRAIL. Therefore, we have been investigating mechanisms to overcome TRAIL resistance in cancer cells so that TRAIL-associated compounds can be used effectively in clinical trials. Epigenetic inactivation of proapoptotic genes, or activation of survival signaling, can cause cross-resistance to several anti-tumor therapies and to immune cytotoxic lymphocytes. We hypothesize that 5-aza-2 deoxycytidine aza-dCR, decitabine may render TRAIL-resistant prostate cancer cells sensitive to caspase-8-mediated apoptosis and may, therefore, be therapeutically efficient. We evaluated the antiproliferative effects of decitabine on the following four prostate cancer cell lines: well-differentiated AR positive LnCaP p53(+), PTEN- and 22rv1 p53(+) and PTEN(+)]; poorly-differentiated AR negative PC3 p53-, PTEN- and DU145 p53 mutant, PTEN(+). Here, we provide evidence that treatment with sub-optimal concentrations of decitabine are additive to TRAIL effects in well-differentiated PCa cells whereas the same treatment shows synergistic effects in poorly-differentiated PCa cells through increased caspase-8 expression, down-modulation of Akt activation and through the expression of certain anti-apoptotic molecules including FLIP, PED/PEA-15, survivin and c-IAP-1. Our findings demonstrate that decitabine at relatively low concentrations restores caspase-8 expression and sensitises resistant PCa cells to TRAIL-induced apoptosis leading to important implications in novel therapeutic strategies targeting defective apoptosis pathways in advanced prostate tumors.
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PMID:Downmodulation of dimethyl transferase activity enhances tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in prostate cancer cells. 1863 60

Effective treatments for advanced prostate cancer are much needed. Toward this goal, we show apoptosis and impaired long-term survival of androgen-independent prostate cancer cells (PC3 and PC3 derivatives) co-treated with the cyclin-dependent kinase (CDK) inhibitor roscovitine and an AKT inhibitor (LY294002 or API-2). Apoptosis of PC3 cells by the drug combination required caspase-9 but not caspase-8 activity and thus is mitochondria-dependent. Roscovitine reduced amounts of the caspase inhibitor XIAP, and API-2 increased amounts of the BH3-only protein Bim. PC3 cells apoptosed when co-treated with API-2 and either cdk9 siRNA, dominant-negative cdk9, or the cdk9 inhibitor DRB; they did not apoptose when co-treated with API-2 and XIAP siRNA. Bax accumulated in mitochondria in response to API-2, whereas release of cytochrome c from mitochondria required both API-2 and roscovitine. We suggest that roscovitine elicits events that activate Bax once it translocates to mitochondria and that inactivation of cdk9 signals these events and the down-regulation of XIAP. Collectively, our data show apoptosis of prostate cancer cells by a drug combination and identify Bax activation as a basis of cooperation.
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PMID:Apoptosis of metastatic prostate cancer cells by a combination of cyclin-dependent kinase and AKT inhibitors. 1870 58


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