title: Differential effects of glutathione depletion and metallothionein induction on the induction of DNA single-strand breaks and cytotoxicity by tert-butyl hydroperoxide in cultured mammalian cells.
abstract: Induction of DNA single-strand breaks (ssb), their resealing and cytotoxicity by tert-butyl hydroperoxide (t-BuOOH) were investigated in cultured Chinese hamster V79 cells. The effect of the depletion of cellular glutathione (GSH), iron chelation and induction of metallothionein (MT) on these parameters was studied. t-BuOOH in a concentration range of 0.02-0.5 mM induced DNA ssb in a dose-dependent fashion. Strand breakage increased as a function of time up to 1 h. Divalent iron chelator o-phenanthroline suppressed markedly the induction of DNA ssb while the trivalent iron chelator desferrioxamine had no effect. GSH-depletion increased cytotoxicity of t-BuOOH. In contrast, the depletion of GSH did not affect the efficiency of formation of DNA ssb by t-BuOOH and the rate of resealing of the DNA damage. The induction of MT did not influence the efficiency of formation of DNA ssb by t-BuOOH. In summary, while GSH depletion and MT induction affected the formation of DNA ssb and cytotoxicity differently divalent iron was required for both. Therefore, appears likely that DNA breakage and cytotoxicity by t-BuOOH are caused by independent mechanisms.
authors.affiliation: Department of Environmental Toxicology, Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ochi
authors.forename: P A
authors.initials: PA
authors.lastname: Cerutti
mesh_terms: D000818:Animals; D019328:Buthionine Sulfoximine; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D004277:DNA, Single-Stranded / Q000187:drug effects*; D005978:Glutathione / Q000378:metabolism*; D007700:Kinetics; D008168:Lung; D008668:Metallothionein / Q000096:biosynthesis*; D008717:Methionine Sulfoximine / Q000031:analogs & derivatives / Q000494:pharmacology; D010545:Peroxides / Q000494:pharmacology*; D020122:tert-Butylhydroperoxide
chemical_list: D004277:DNA, Single-Stranded; D010545:Peroxides; D008717:Methionine Sulfoximine; D019328:Buthionine Sulfoximine; D008668:Metallothionein; D020122:tert-Butylhydroperoxide; D005978:Glutathione