title: 1,2-Dichloropropane generates phosphorylated histone H2AX via cytochrome P450 2E1-mediated metabolism.
abstract: 1,2-Dichloropropane (1,2-DCP), a synthetic chlorinated solvent, was recently classified as carcinogenic. Genotoxic events are known as a crucial step in the initiation of cancer. However, studies on the genotoxicity of 1,2-DCP are very limited, particularly studies investigating the mechanism behind DNA damage by 1,2-DCP. In this study, we examined the genotoxicity of 1,2-DCP using phosphorylated histone H2AX (γ-H2AX), a sensitive DNA damage marker. 1,2-DCP showed dose- (1-10mM: 4h) and time-dependent (1-24h: 5mM) γ-H2AX generation in cultured human hepatocytes (WRL-68) and cholangiocytes (MMNK-1). Additionally, γ-H2AX generation was observed in the livers of mice inhalationally exposed to 1,2-DCP at concentrations of 100, 200, and 400 ppm. During an in vitro mechanistic investigation, we found that γ-H2AX generation by 1,2-DCP was clearly attenuated in the presence of disulfiram and 4-methylpyrazole, a specific cytochrome P450 2E1 (CYP2E1) inhibitor. Furthermore, we showed that 1,2-DCP increased the levels of intracellular reactive oxygen species (ROS), with the increase significantly inhibited by CYP2E1 inhibitors. These results suggested that ROS produced via the cytochrome P450 2E1 metabolic process of 1,2-DCP was a major causal factor for γ-H2AX generation by treatment with 1,2-DCP.
authors.affiliation: Industrial Toxicology and Health Effects Research Group, National Institute of Occupational Safety and Health, Japan. Electronic address: toyooka@h.jniosh.go.jp.
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Toyooka
authors.affiliation: Industrial Toxicology and Health Effects Research Group, National Institute of Occupational Safety and Health, Japan.
authors.forename: Yukie
authors.initials: Y
authors.lastname: Yanagiba
authors.affiliation: Industrial Toxicology and Health Effects Research Group, National Institute of Occupational Safety and Health, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Suda
authors.affiliation: Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ibuki
authors.affiliation: Industrial Toxicology and Health Effects Research Group, National Institute of Occupational Safety and Health, Japan.
authors.forename: Rui-Sheng
authors.initials: RS
authors.lastname: Wang
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism*; D065691:Cytochrome P-450 CYP2E1 Inhibitors / Q000494:pharmacology; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006657:Histones / Q000096:biosynthesis*; D006801:Humans; D019570:Inhalation Exposure; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D009153:Mutagens / Q000633:toxicity*; D010766:Phosphorylation; D011407:Propane / Q000031:analogs & derivatives* / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism; D013997:Time Factors
chemical_list: D019392:Cytochrome P-450 CYP2E1; D065691:Cytochrome P-450 CYP2E1 Inhibitors; D006657:Histones; D009153:Mutagens; D011407:Propane; D017382:Reactive Oxygen Species; C468783:H2AX protein, human; C004765:propylene dichloride; C475961:gamma-H2AX protein, mouse
keywords: 1,2-Dichloropropane; Cytochrome P450 2E1; Genotoxicity; Phosphorylated histone H2AX; Reactive oxygen species