title: Calcium and reactive oxygen species mediate staurosporine-induced mitochondrial dysfunction and apoptosis in PC12 cells.
abstract: The bacterial alkaloid staurosporine is widely employed as an inducer of apoptosis in many cell types including neurons. The intracellular cascades that mediate staurosporine-induced apoptosis are largely unknown. Exposure of cultured PC12 cells to staurosporine resulted in a rapid (min) and prolonged (1-6 hr) elevation of intracellular free calcium levels [Ca2+]i, accumulation of mitochondrial reactive oxygen species (ROS), and decreased mitochondrial 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction (1-4 hr). These early events were followed by membrane lipid peroxidation, loss of mitochondrial transmembrane potential, and nuclear apoptotic changes. Treatment of cells with serum or nerve growth factor within 1-2 hr of staurosporine exposure resulted in recovery of [Ca2+]i and ROS levels, and rescued the cells from apoptosis. The increased [Ca2+]i and ROS production were required for staurosporine-induced apoptosis because the intracellular calcium chelator BAPTA and uric acid (an agent that scavenges peroxynitrite) each protected cells against apoptosis. The caspase inhibitor zVAD-fmk and the anti-apoptotic gene product Bcl-2 prevented the sustained [Ca2+]i increase and ROS accumulation induced by staurosporine indicating that caspases act very early in the apoptotic process. Our data indicate that a [Ca2+]i increase is an early and critical event in staurosporine-induced apoptosis that engages a cell death pathway involving ROS production, oxidative stress, and mitochondrial dysfunction.
authors.affiliation: Sanders-Brown Research Center on Aging and Department of Anatomy and Neurobiology, University of Kentucky, Lexington 40536-0230, USA.
authors.forename: I
authors.initials: I
authors.lastname: Kruman
authors.forename: Q
authors.initials: Q
authors.lastname: Guo
authors.forename: M P
authors.initials: MP
authors.lastname: Mattson
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002614:Chelating Agents / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D016716:PC12 Cells; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D019311:Staurosporine / Q000494:pharmacology*
chemical_list: D002614:Chelating Agents; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D019311:Staurosporine; D002118:Calcium