title: Rho-kinase inhibitor Y-27632 attenuates arsenic trioxide toxicity in H9c2 cardiomyoblastoma cells.
abstract: The purpose of this study is to examine the molecular mechanism underlying the toxicity of arsenic trioxide (ATO) in cardiac cells. H9c2 rat cardiomyoblastoma cells undergo apoptosis during exposure to the concentrations of ATO > 10 μM for 24 h. The process is accompanied by the activation of caspases and is suppressed by the pan-caspase inhibitor z-VAD. Since ATO-induced H9c2 cell death is suppressed by Rho-kinase (ROCK) inhibitor Y-27632, but not by any antioxidants tested, apoptosis by ATO seems to be initiated through a ROCK-dependent and reactive oxygen species-independent mechanism. During the execution of apoptosis by ATO, the induction of autophagy is also observed. Importantly, autophagy is accelerated in cells treated with ATO plus Y-27632, although Y-27632 alone does not induce autophagy. The cytoprotective effect of Y-27632 against ATO toxicity is abrogated by the co-administration of an autophagy inhibitor, 3-methyladenine, suggesting that autophagy contributes to the cytoprotection by Y-27632. Taken together, the data indicate that the activation of ROCK is required for apoptotic H9c2 cardiomyoblastoma cell death by ATO, and that the ROCK inhibition not only inhibits caspase-dependent apoptotic machinery, but also causes a rise in the cytoprotective autophagy processes during ATO exposure.
authors.affiliation: Section of Forensic Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
authors.forename: Marie
authors.initials: M
authors.lastname: Bessho
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Aki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Funakoshi
authors.forename: Kana
authors.initials: K
authors.lastname: Unuma
authors.forename: Kanako
authors.initials: K
authors.lastname: Noritake
authors.forename: Chizuru
authors.initials: C
authors.lastname: Kato
authors.forename: Koichi
authors.initials: K
authors.lastname: Uemura
mesh_terms: D000577:Amides / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000037:antagonists & inhibitors*; D001343:Autophagy / Q000187:drug effects; D015153:Blotting, Western; D002316:Cardiotonic Agents; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005822:Genetic Vectors; D010087:Oxides / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D011725:Pyridines / Q000494:pharmacology*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D014162:Transfection; D014746:Vimentin / Q000378:metabolism; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000577:Amides; D000975:Antioxidants; D001152:Arsenicals; D002316:Cardiotonic Agents; D004791:Enzyme Inhibitors; D010087:Oxides; D011725:Pyridines; D017382:Reactive Oxygen Species; D014746:Vimentin; C108830:Y 27632; D054460:rho-Associated Kinases; D020169:Caspases; D000077237:Arsenic Trioxide