title: Role of oxyradicals in mutagenicity and DNA damage induced by crocidolite asbestos in mammalian cells.
abstract: Crocidolite, one of the most carcinogenic forms of asbestos, is mutagenic in cultured mammalian cells when assayed using a system that can detect multilocus deletions. In the present study, we examined the effect of buthionine sulfoximine (BSO) on mutation frequency and the formation of 8-hydroxydeoxyguanosine (8-OHdG) in human-hamster hybrid (A(L)) cells induced by crocidolite fibers in an attempt to determine the role of oxyradicals in mediating fiber mutagenesis. BSO, a competitive inhibitor of the enzyme gamma-glutamyl cysteine synthetase, depleted nonprotein sulfhydryls to <5% of control within 24 h at a nonmutagenic dose of 25 microM. In cells pretreated with BSO for 24 h, the mutation yield at the CD59 locus induced by a 4 microg/cm2 dose of crocidolite fibers was increased by more than 3-fold (P < 0.05). Using immunoperoxidase staining with a monoclonal antibody specific for 8-OHdG, we demonstrated that crocidolite fibers induced a dose-dependent increase in oxidative DNA damage in A(L) cells. Furthermore, addition of DMSO, a well-established hydroxyl radical (OH*) scavenger, dramatically suppressed 8-OHdG induction (P < 0.005). Our results definitely demonstrate that reactive oxygen species mediate fiber-induced DNA damage mutagenesis in A(L) cells in a concentration-dependent manner.
authors.affiliation: Center for Radiological Research, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
authors.forename: A
authors.initials: A
authors.lastname: Xu
authors.forename: L J
authors.initials: LJ
authors.lastname: Wu
authors.forename: R M
authors.initials: RM
authors.lastname: Santella
authors.forename: T K
authors.initials: TK
authors.lastname: Hei
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D001194:Asbestos / Q000633:toxicity*; D017638:Asbestos, Crocidolite / Q000633:toxicity*; D019328:Buthionine Sulfoximine / Q000633:toxicity*; D016466:CHO Cells; D002455:Cell Division; D006224:Cricetinae; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000032:analysis; D005609:Free Radicals / Q000378:metabolism; D006801:Humans; D006822:Hybrid Cells; D007124:Immunoenzyme Techniques; D007700:Kinetics; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D005609:Free Radicals; D009153:Mutagens; D013438:Sulfhydryl Compounds; D017638:Asbestos, Crocidolite; D001194:Asbestos; D019328:Buthionine Sulfoximine; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine