Risk assessment of hydroquinone: differential responses of cell growth and lethality correlated to hydroquinone concentration.
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.
Kim
Yang Jee
YJ
School of Public Health, Seoul National University, Seoul, Korea.
Woo
Hae Dong
HD
Kim
Byeong Mo
BM
Lee
Young Joon
YJ
Kang
Su Jin
SJ
Cho
Yoon Hee
YH
Chung
Hai Won
HW
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
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