title: 2,3,7,8-tetrachlorobenzo-p-dioxin inhibits proliferation of SK-N-SH human neuronal cells through decreased production of reactive oxygen species.
abstract: Oxidative stress has been known to be involved in the mechanism of toxic effects of various agents on many cellular systems. In this study we investigated the role of reactive oxygen species (ROS) in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced neuronal cell toxicity using SK-N-SH human neuroblastoma cells. TCDD inhibited proliferation of the cells in a dose-dependent manner, which was revealed by MTT staining, counting of cells stained with trypan blue and [3H]thymidine uptake assay. TCDD also suppressed the basal generation of ROS in a time- and concentration-dependent manner assessed by 2',7'-dichlorofluorescein fluorescence. In addition, TCDD induced a dose-dependent inhibition of lipid peroxidation, a biomarker of oxidative stress, whereas it significantly increased the level of glutathione (GSH), an intracellular free radical scavenger in the cells. Moreover, TCDD altered the activities of major antioxidant enzymes; increase in superoxide dismutase (SOD) and catalase, but decrease in glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Red). Pretreatment with L-buthionine-S,R-sulfoximine (BSO, 50 microM), an inhibitor of GSH synthesis, significantly prevented the TCDD-induced reduction in lipid peroxidation and cell proliferation. Interestingly, exogenous application of an oxidant, H2O2 (50 microM) markedly restored the inhibited cell proliferation induced by TCDD. Taken together, these results suggest that alteration of cellular redox balance may mediate the TCDD-induced inhibition of proliferation in human neuronal cells.
authors.affiliation: College of Pharmacy, Duksung Women's University, Seoul 132-714, South Korea.
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Lee
authors.forename: Da-Qing
authors.initials: DQ
authors.lastname: Jin
authors.forename: Seung Hee
authors.initials: SH
authors.lastname: Park
authors.forename: Soon Young
authors.initials: SY
authors.lastname: Han
authors.forename: Hyung Sik
authors.initials: HS
authors.lastname: Kim
authors.forename: Tae Cheon
authors.initials: TC
authors.lastname: Jeong
authors.forename: Keun
authors.initials: K
authors.lastname: Huh
authors.forename: Jung-Ae
authors.initials: JA
authors.lastname: Kim
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D016923:Cell Death; D002455:Cell Division; D004396:Coloring Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D015227:Lipid Peroxidation; D009474:Neurons / Q000378:metabolism; D010084:Oxidation-Reduction; D000072317:Polychlorinated Dibenzodioxins; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase / Q000378:metabolism; D013723:Teratogens; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors; D014343:Trypan Blue / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D000964:Antimetabolites, Antineoplastic; D004396:Coloring Agents; D000072317:Polychlorinated Dibenzodioxins; D017382:Reactive Oxygen Species; D013723:Teratogens; D013778:Tetrazolium Salts; D013844:Thiazoles; D019328:Buthionine Sulfoximine; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; C022616:thiazolyl blue; D005978:Glutathione; D014343:Trypan Blue