Peroxyl radical mediated oxidative DNA base damage: implications for lipid peroxidation induced mutagenesis.
Endogenous DNA damage induced by lipid peroxidation is believed to play a critical role in carcinogenesis. Lipid peroxidation generates free radical intermediates (primarily peroxyl radicals, ROO(*)) and electrophilic aldehydes as the principal genotoxicants. Although detailed information is available on the role of aldehyde base adducts in mutagenesis and carcinogenesis, the contribution of peroxyl radical mediated DNA base damage is less well understood. In the present study we have mapped oxidative base damage induced by peroxyl radicals in the supF tRNA gene and correlated this information with peroxidation-induced mutations in several human fibroblast cell lines. Nearly identical patterns of oxidative base damage were obtained from reaction of DNA with either peroxidizing arachidonic acid (20:4omega6) or peroxyl radicals generated by thermolysis of ABIP in the presence of oxygen. Oxidative base damage primarily occurred at G and C. Transversions at GC base pairs in the supF gene were the major base substitution detected in all cell lines. Peroxyl radical induced tandem mutations were also observed. Many mutation hot spots coincided with sites of mapped oxidative lesions, although in some cases hot spots occurred adjacent to the damaged base. Evidence is presented for the involvement of 8-oxodG in the oxidation of DNA by ROO(*). These results are used to interpret some key features of previously published mutation spectra induced by lipid peroxidation in human cells.
Lim
Punnajit
P
Division of Molecular Biology and Biology, Beckman Research Institute of the City of Hope, 1450 East Duarte Road, Duarte, California 91010, USA.
Wuenschell
Gerald E
GE
Holland
Vanessa
V
Lee
Dong-Hyun
DH
Pfeifer
Gerd P
GP
Rodriguez
Henry
H
Termini
John
J
D016718:Arachidonic Acid / Q000633:toxicity; D001391:Azo Compounds / Q000633:toxicity; D001483:Base Sequence / Q000187:drug effects; D002461:Cell Line, Transformed; D004249:DNA Damage; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000378:metabolism*; D005609:Free Radicals / Q000633:toxicity; D008401:Gas Chromatography-Mass Spectrometry; D016153:Genes, Suppressor; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000633:toxicity; D015227:Lipid Peroxidation / Q000235:genetics*; D016296:Mutagenesis; D018384:Oxidative Stress; D010100:Oxygen / Q000633:toxicity; D010545:Peroxides / Q000633:toxicity*; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism
D001391:Azo Compounds; D004269:DNA, Bacterial; D005609:Free Radicals; D007093:Imidazoles; D010545:Peroxides; C430118:VA 061; C096275:supF tRNA; D016718:Arachidonic Acid; C049375:perhydroxyl radical; C024829:8-hydroxyguanine; D006147:Guanine; D012343:RNA, Transfer; D010100:Oxygen