DNA damage and mutations induced by arachidonic acid peroxidation.
Endogenous cellular oxidation of omega6-polyunsaturated fatty acids (PUFAs) has long been recognized as a contributing factor in the development of various cancers. The accrual of DNA damage as a result of reaction with free radical and electrophilic aldehyde products of lipid peroxidation is believed to be involved; however, the genotoxic and mutation-inducing potential of specific membrane PUFAs remains poorly defined. In the present study we have examined the ability of peroxidizing arachidonic acid (AA, 20:4omega6) to induce DNA strand breaks, base modifications, and mutations. The time-dependent induction of single-strand breaks and oxidative base modifications by AA in genomic DNA was quantified using denaturing glyoxal gel electrophoresis. Mutation spectra were determined in XP-G fibroblasts and a repair-proficient line corrected for this defect by c-DNA complementation (XP-G(+)). Mutation frequencies were elevated from approximately 5- to 30-fold over the background following reaction of DNA with AA for various times. The XPG gene product was found to be involved in the suppression of mutations after extended reaction of DNA with AA. Arachidonic acid-induced base substitutions were consistent with the presence of both oxidized and aldehyde base adducts in DNA. The frequency of multiple-base substitutions induced by AA was significantly reduced upon correction for the XPG defect (14% vs 2%, P = 0.0015). Evidence is also presented which suggests that the induced frequency of multiple mutations is lesion dependent. These results are compared to published data for mutations stimulated by alpha,beta-unsaturated aldehydes identified as products of lipid peroxidation.
Lim
Punnajit
P
Division of Molecular Biology, Beckman Research Institute of the City of Hope, 1450 East Duarte Road, Duarte, California 91010, USA.
Sadre-Bazzaz
Kianoush
K
Shurter
Jesse
J
Sarasin
Alain
A
Termini
John
J
D016718:Arachidonic Acid / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D001483:Base Sequence; D002460:Cell Line; D019457:Chromosome Breakage / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D004252:DNA Mutational Analysis; D004260:DNA Repair / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D005816:Genetic Complementation Test; D006801:Humans; D015227:Lipid Peroxidation / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010084:Oxidation-Reduction; D017384:Sequence Deletion / Q000235:genetics; D014983:Xeroderma Pigmentosum / Q000235:genetics / Q000378:metabolism / Q000473:pathology
D005609:Free Radicals; D016718:Arachidonic Acid; D004247:DNA