title: Mechanism for generation of hydrogen peroxide and change of mitochondrial membrane potential during rotenone-induced apoptosis.
abstract: Rotenone, an inhibitor of NADH dehydrogenase complex, is a naturally occurring insecticide, which is capable of inducing apoptosis. Rotenone-induced apoptosis is considered to contribute to its anticancer effect and the etiology of Parkinson's disease (PD). We demonstrated that rotenone induced internucleosomal DNA fragmentation, DNA ladder formation, in human cultured cells, HL-60 (promyelocytic leukemia) and BJAB cells (B-cell lymphoma). Flow cytometry showed that rotenone induced H2O2 generation, followed by significant changes in the mitochondrial membrane potential (DeltaPsim). Caspase-3 activity increased in HL-60 cells in a time-dependent manner. These apoptotic events were delayed in HP100 cells, an H2O2-resistant clone of HL-60, confirming the involvement of H2O2 in apoptosis. Expression of anti-apoptotic protein, Bcl-2, in BJAB cells drastically inhibited DeltaPsim change and DNA ladder formation but not H2O2 generation, confirming the participation of mitochondrial dysfunction in apoptosis. NAD(P)H oxidase inhibitors prevented H2O2 generation and DNA ladder formation. These results suggest that rotenone induces O2(-)-derived H2O2 generation through inhibition of NADH dehydrogenase complex and/or activation of NAD(P)H oxidase, and H2O2 generation causes the disruption of mitochondrial membrane in rotenone-induced apoptosis.
authors.affiliation: Department of Environmental and Molecular Medicine, Mie University School of Medicine, 2-174 Edobashi, -Tsu-shi, Mie, 514-8507, Japan.
authors.forename: Saeko
authors.initials: S
authors.lastname: Tada-Oikawa
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hiraku
authors.forename: Michiko
authors.initials: M
authors.lastname: Kawanishi
authors.forename: Shosuke
authors.initials: S
authors.lastname: Kawanishi
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007306:Insecticides / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009245:NADH Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism; D019255:NADPH Oxidases / Q000096:biosynthesis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012402:Rotenone / Q000494:pharmacology*
chemical_list: D004273:DNA, Neoplasm; D007306:Insecticides; D019253:Proto-Oncogene Proteins c-bcl-2; D012402:Rotenone; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases; D009245:NADH Dehydrogenase