title: Dual silencing of Hsp27 and c-FLIP enhances doxazosin-induced apoptosis in PC-3 prostate cancer cells.
abstract: We evaluated effect of dual gene silencing of Hsp27 and c-FLIP in doxazosin-induced apoptosis of PC-3 cell. After transfection using Hsp27 and c-FLIP siRNA mixture (dual silencing), doxazosin treatment was done at the concentrations of 1, 10, and 25  μ M. We checked apoptosis of PC-3 cells with and TUNEL staining. We also checked interaction between Hsp27 and C-FLIP in the process of apoptosis inhibition. Spontaneous apoptotic index was 5% under single gene silencing of Hsp27 and c-FLIP and 7% under dual silencing of Hsp27 and c-FLIP. When doxazosin treatment was added, apoptotic indices increased in a dose-dependent manner (1, 10, and 25  μ M): nonsilencing 10, 27, and 52%; Hsp27-silencing: 14, 35, and 68%; c-FLIP silencing: 21, 46, and 78%; dual silencing: 38, 76, and 92%. While c-FLIP gene expression decreased in Hsp27- silenced cells, Hsp27 gene expression showed markedly decreased pattern in the cells of c-FLIP silencing. The knockout of c-FLIP and Hsp27 genes together enhances apoptosis even under 1  μ M, rather than low concentration, of doxazosin in PC-3 cells. This finding suggests a new strategy of multiple knockout of antiapoptotic and survival factors in the treatment of late-stage prostate cancer refractory to conventional therapy.
authors.affiliation: Eulji Medi-Bio Research Institute, Seoul 139-871, Republic of Korea.
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Hee-Ju
authors.initials: HJ
authors.lastname: Cho
authors.forename: Jeong-Man
authors.initials: JM
authors.lastname: Cho
authors.forename: Jung Yoon
authors.initials: JY
authors.lastname: Kang
authors.forename: Hyun-Won
authors.initials: HW
authors.lastname: Yang
authors.forename: Tag Keun
authors.initials: TK
authors.lastname: Yoo
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage; D017209:Apoptosis / Q000187:drug effects*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000235:genetics*; D045744:Cell Line, Tumor; D017292:Doxazosin / Q000008:administration & dosage*; D004357:Drug Synergism; D020868:Gene Silencing; D015316:Genetic Therapy / Q000379:methods; D055551:HSP27 Heat-Shock Proteins / Q000235:genetics*; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D055551:HSP27 Heat-Shock Proteins; D017292:Doxazosin