title: Risk assessment of hydroquinone: differential responses of cell growth and lethality correlated to hydroquinone concentration.
abstract: Hydroquinone (HQ) is a major metabolite of benzene and has been used as an antioxidant, a stabilizer, a photographic reducer, and an ingredient in skin lighteners. In this study, the effects of low (5 microM) and high (50 microM) concentrations of HQ were investigated on cell growth and lethality in Jurkat cells. Intracellular reactive oxygen species (ROS) levels were increased with both HQ concentrations. Fifty micromolar HQ markedly increased phosphorylation of ERK and activation of caspase-9/-3, followed by PARP cleavage. The addition of ERK inhibitor PD98059 or N-acetylcysteine (NAC) abolished HQ-induced apoptosis. Five micromolar HQ activated ERK protein, but not JNK or p38. However, S-phase recruitment was decreased by preincubation with NAC, but not PD98059. Thus, high levels of ROS contributed to HQ-induced apoptosis via ERK signaling and the caspase pathway, whereas low quantities of ROS resulted in S-phase recruitment in the cell-cycle distribution.
authors.affiliation: School of Public Health, Seoul National University, Seoul, Korea.
authors.forename: Yang Jee
authors.initials: YJ
authors.lastname: Kim
authors.forename: Hae Dong
authors.initials: HD
authors.lastname: Woo
authors.forename: Byeong Mo
authors.initials: BM
authors.lastname: Kim
authors.forename: Young Joon
authors.initials: YJ
authors.lastname: Lee
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Kang
authors.forename: Yoon Hee
authors.initials: YH
authors.lastname: Cho
authors.forename: Hai Won
authors.initials: HW
authors.lastname: Chung
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005419:Flavonoids; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D006873:Hydroquinones / Q000008:administration & dosage* / Q000633:toxicity*; D019169:Jurkat Cells
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D006873:Hydroquinones; D048049:Extracellular Signal-Regulated MAP Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; C031927:hydroquinone