title: The natural anticancer agent plumbagin induces potent cytotoxicity in MCF-7 human breast cancer cells by inhibiting a PI-5 kinase for ROS generation.
abstract: Drug-induced haploinsufficiency (DIH) in yeast has been considered a valuable tool for drug target identification. A plant metabolite, plumbagin, has potent anticancer activity via reactive oxygen species (ROS) generation. However, the detailed molecular targets of plumbagin for ROS generation are not understood. Here, using DIH and heterozygous deletion mutants of the fission yeast Schizosaccharomyces pombe, we identified 1, 4-phopshatidylinositol 5-kinase (PI5K) its3 as a new molecular target of plumbagin for ROS generation. Plumbagin showed potent anti-proliferative activity (GI(50); 10 µM) and induced cell elongation and septum formation in wild-type S. pombe. Furthermore, plumbagin dramatically increased the intracellular ROS level, and pretreatment with the ROS scavenger, N-acetyl cysteine (NAC), protected against growth inhibition by plumbagin, suggesting that ROS play a crucial role in the anti-proliferative activity in S. pombe. Interestingly, significant DIH was observed in an its3-deleted heterozygous mutant, in which ROS generation by plumbagin was higher than that in wild-type cells, implying that its3 contributes to ROS generation by plumbagin in this yeast. In MCF7 human breast cancer cells, plumbagin significantly decreased the level of a human ortholog, 1, 4-phopshatidylinositol 5-kinase (PI5K)-1B, of yeast its3, and knockdown of PI5K-1B using siPI5K-1B increased the ROS level and decreased cell viability. Taken together, these results clearly show that PI5K-1B plays a crucial role in ROS generation as a new molecular target of plumbagin. Moreover, drug target screening using DIH in S. pombe deletion mutants is a valuable tool for identifying molecular targets of anticancer agents.
authors.affiliation: S. pombe Research Team, Gene-to-Drug Division, Bioneer Corporation, Daejeon, Republic of Korea.
authors.forename: Ju-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Yeon
authors.forename: Hanna
authors.initials: H
authors.lastname: Kim
authors.forename: Whijae
authors.initials: W
authors.lastname: Roh
authors.forename: Jeiwook
authors.initials: J
authors.lastname: Chae
authors.forename: Han-Oh
authors.initials: HO
authors.lastname: Park
authors.forename: Dong-Myung
authors.initials: DM
authors.lastname: Kim
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology*; D016923:Cell Death / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D005260:Female; D055785:Gene Knockdown Techniques; D057895:Haploinsufficiency / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D061986:MCF-7 Cells; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009285:Naphthoquinones / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000166:cytology / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D009285:Naphthoquinones; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase; C014758:plumbagin