title: Doxorubicin-induced oxidative stress: The protective effect of nicorandil on HL-1 cardiomyocytes.
abstract: The primary cardiotoxic action of doxorubicin when used as antitumor drug is attributed to the generation of reactive oxygen species (ROS) therefore effective cardioprotection therapies are needed. In this sense, the antianginal drug nicorandil has been shown to be effective in cardioprotection from ischemic conditions but the underlying molecular mechanism to cope with doxorubicin-induced ROS is unclear. Our in vitro study using the HL-1 cardiomyocyte cell line derived from mouse atria reveals that the endogenous nitric oxide (NO) production was stimulated by nicorandil and arrested by NO synthase inhibition. Moreover, while the NO synthase activity was inhibited by doxorubicin-induced ROS, the NO synthase inhibition did not affect doxorubicin-induced ROS. The inhibition of NO synthase activity by doxorubicin was totally prevented by preincubation with nicorandil. Nicorandil also concentration-dependently (10 to 100 μM) decreased doxorubicin-induced ROS and the effect was antagonized by 5-hydroxydecanoate. The inhibition profile of doxorubicin-induced ROS by nicorandil was unaltered when an L-arginine derivative or a protein kinase G inhibitor was present. Preincubation with pinacidil mimicked the effect of nicorandil and the protection was eliminated by glibenclamide. Quantitative colocalization of fluorescence indicated that the mitochondrion was the target organelle of nicorandil and the observed response was a decrease in the mitochondrial inner membrane potential. Interference with H+ movement across the mitochondrial inner membrane, leading to depolarization, also protected from doxorubicin-induced ROS. The data indicate that activation of the mitochondrial ATP-sensitive K+ channel by nicorandil causing mitochondrial depolarization, without participation of the NO donor activity, was responsible for inhibition of the mitochondrial NADPH oxidase that is the main contributor to ROS production in cardiomyocytes. Impairment of the cytosolic Ca2+ signal induced by caffeine and the increase in lipid peroxidation, both of which are indicators of doxorubicin-induced oxidative stress, were also prevented by nicorandil.
authors.affiliation: Cardiología Clínica y Experimental, Laboratorios de Investigación Biomédica, Universidad de Murcia en Campus de El Palmar, Murcia, Spain.
authors.forename: Mari C
authors.initials: MC
authors.lastname: Asensio-López
authors.affiliation: Departamento de Bioquímica y Biología Molecular A, Universidad de Murcia en Campus de Espinardo, Murcia, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Soler
authors.affiliation: Cardiología Clínica y Experimental, Laboratorios de Investigación Biomédica, Universidad de Murcia en Campus de El Palmar, Murcia, Spain.|Servicio de Cardiología, Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain.
authors.forename: Domingo
authors.initials: D
authors.lastname: Pascual-Figal
authors.affiliation: Departamento de Bioquímica y Biología Molecular A, Universidad de Murcia en Campus de Espinardo, Murcia, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Fernández-Belda
authors.affiliation: Cardiología Clínica y Experimental, Laboratorios de Investigación Biomédica, Universidad de Murcia en Campus de El Palmar, Murcia, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Lax
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D004317:Doxorubicin / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism*; D020108:Nicorandil / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D020108:Nicorandil; D009569:Nitric Oxide; D004317:Doxorubicin; D019001:Nitric Oxide Synthase; D002118:Calcium