title: Sequence- and region-specificity of oxaliplatin adducts in naked and cellular DNA.
abstract: Oxaliplatin is a clinical anticancer drug with a pharmacological profile distinct from that of cisplatin. Our studies compared site- and region-specificity of lesions induced by oxaliplatin and cisplatin in naked and intracellular DNA, respectively. Oxaliplatin adducts in naked Simian virus 40 (SV40 DNA) were mapped by repetitive primer extension. The sites of oxaliplatin adducts were nearly identical to the sites of cisplatin adducts and were focused in G clusters and GNG motifs probably reflecting intrastrand cross-links. Although alkaline agarose electrophoresis of specific SV40 fragments showed that oxaliplatin formed interstrand cross-links, the levels of this lesion type were low. Drug-induced lesions in discrete loci of cellular DNA were assessed by the polymerase chain reaction stop assay in human tumor A2780 cells. Oxaliplatin at 200 microM induced approximately 1300, approximately 1500, approximately 800, and approximately 300 lesions/10(6) bp in the human beta-globin, c-myc, and HPRT genes and in mitochondrial DNA, respectively. Cisplatin formed two to six times more lesions in the same regions. For both drugs, lesion frequencies seem to parallel the density of drug-binding motifs in the nuclear regions, whereas mitochondrial DNA was disproportionately less affected. Despite less potent induction of DNA lesions, oxaliplatin was more cytotoxic than cisplatin against A2780 cells. Because our findings clearly demonstrate that oxaliplatin forms covalent adducts with a similar sequence- and region-specificity to that of cisplatin, other properties of oxaliplatin adducts, factors other than DNA binding, or both determine the unique features of the mechanism of action of oxaliplatin.
authors.affiliation: Cancer Therapy and Research Center, Institute for Drug Development, San Antonio, Texas 78245, USA. jmw1@saci.org
authors.forename: J M
authors.initials: JM
authors.lastname: Woynarowski
authors.forename: W G
authors.initials: WG
authors.lastname: Chapman
authors.forename: C
authors.initials: C
authors.lastname: Napier
authors.forename: M C
authors.initials: MC
authors.lastname: Herzig
authors.forename: P
authors.initials: P
authors.lastname: Juniewicz
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism* / Q000633:toxicity; D001483:Base Sequence; D002460:Cell Line; D002522:Chlorocebus aethiops; D002945:Cisplatin / Q000378:metabolism / Q000633:toxicity; D003432:Cross-Linking Reagents / Q000378:metabolism / Q000633:toxicity; D018736:DNA Adducts / Q000096:biosynthesis* / Q000378:metabolism; D004249:DNA Damage; D004272:DNA, Mitochondrial / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D009944:Organoplatinum Compounds / Q000378:metabolism* / Q000633:toxicity; D000077150:Oxaliplatin; D012680:Sensitivity and Specificity; D013539:Simian virus 40 / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D003432:Cross-Linking Reagents; D018736:DNA Adducts; D004272:DNA, Mitochondrial; D004279:DNA, Viral; D009944:Organoplatinum Compounds; C057270:cisplatin-DNA adduct; D000077150:Oxaliplatin; D002945:Cisplatin