Generation of phosphorylated histone H2AX by benzene metabolites.
Benzene is a well known environmental carcinogen which causes myeloid leukemia. DNA damage induced by benzene metabolites such as hydroquinone (HQ) and p-benzoquinone (BQ) is one reason for the leukemogenesis. In this study, we showed that treatment with HQ and BQ quickly and clearly generated phosphorylated histone H2AX (gamma-H2AX) which has been recently considered an index of the production of double strand breaks (DSBs). HQ and BQ produced discrete foci of gamma-H2AX within the nucleus of HL-60 cells in a dose-dependent manner. gamma-H2AX appeared after the treatment with HQ and BQ for 2h, and increased time-dependently up to 4-8h. HQ and BQ increased intracellular oxidation, and an antioxidant, N-acetylcysteine, clearly inhibited the phosphorylation, suggesting that reactive oxygen species produced from HQ and BQ contributed to the generation. gamma-H2AX was sensitively detected after treatment with low concentrations of HQ and BQ, compared with the direct detection of DSBs by biased sinusoidal field gel electrophoresis and with the assessment of cytotoxicity based on cell survival. DSBs are the most serious form of DNA damage and are associated with genomic instability leading to myeloid leukemia. gamma-H2AX may be a useful tool for judging the genotoxicity of benzene metabolites sensitively.
Ishihama
Mio
M
Laboratory of Radiation Biology, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Shizuoka-shi 422-8526, Japan.
Toyooka
Tatsushi
T
Ibuki
Yuko
Y
D001554:Benzene / Q000378:metabolism; D016227:Benzoquinones / Q000008:administration & dosage / Q000633:toxicity*; D002470:Cell Survival / Q000187:drug effects; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004587:Electrophoresis, Agar Gel / Q000379:methods; D018922:HL-60 Cells; D006657:Histones / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D006873:Hydroquinones / Q000008:administration & dosage / Q000633:toxicity*; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism; D009153:Mutagens / Q000008:administration & dosage / Q000633:toxicity*; D010766:Phosphorylation / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D013997:Time Factors
D016227:Benzoquinones; C468783:H2AX protein, human; D006657:Histones; D006873:Hydroquinones; D009153:Mutagens; D017382:Reactive Oxygen Species; C004532:quinone; D001554:Benzene; C031927:hydroquinone