title: Diphenyleneiodonium induces ROS-independent p53 expression and apoptosis in human RPE cells.
abstract: The diphenyleneiodonium (DPI) is widely used as an inhibitor of flavoenzymes, particularly NADPH oxidase. In this study, we investigated the effect of DPI on the apoptosis of human RPE cells. DPI treatment in ARPE-19 cells evoked a dose- and time-dependent growth inhibition, and also induced DNA fragmentation and protein content of the proapoptotic factor Bax. In addition, DPI significantly induced the expression and phosphorylation of p53, which induces proapoptotic genes in response to DNA damage or irreparable cell cycle arrest. ROS have been implicated as a key factor in the activation of p53 by many chemotherapeutic drugs. Recent data on the regulation of intracellular ROS by DPI are controversial. Therefore, we analyzed whether DPI could contribute to the generation of intracellular ROS. Although there was increase in ROS level from cells treated for 24h with DPI, it was not detectable at early time points, required to induce p53 expression. And DPI-induced p53 expression was not affected by the ROS scavenger NAC. We conclude that DPI induces the expression of p53 by ROS-independent mechanism in ARPE-19 cells, and renders cells sensitive to drug-induced apoptosis by induction of p53 expression.
authors.affiliation: Department of Anatomy and Cell Biology, Dong-A University School of Medicine, Busan 602-714, South Korea.
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Park
authors.forename: Ju Dong
authors.initials: JD
authors.lastname: Song
authors.forename: Kang Mi
authors.initials: KM
authors.lastname: Kim
authors.forename: Yeong Min
authors.initials: YM
authors.lastname: Park
authors.forename: Nam Deuk
authors.initials: ND
authors.lastname: Kim
authors.forename: Young Hyun
authors.initials: YH
authors.lastname: Yoo
authors.forename: Young Chul
authors.initials: YC
authors.lastname: Park
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis; D002478:Cells, Cultured; D053938:DNA Fragmentation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors; D009861:Onium Compounds / Q000494:pharmacology*; D010857:Pigment Epithelium of Eye / Q000187:drug effects* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D000098:Acetophenones; D000975:Antioxidants; D004791:Enzyme Inhibitors; D009861:Onium Compounds; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; C007517:diphenyleneiodonium; C056165:acetovanillone; D019255:NADPH Oxidases