Sequence- and region-specificity of oxaliplatin adducts in naked and cellular DNA
Sequence- and region-specificity of oxaliplatin adducts in naked and cellular DNA
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DOI：
10.1124/mol.54.5.770
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发表时间：
1998-11-01
影响因子：
3.6
通讯作者：
Juniewicz, P
中科院分区：
文献类型：
--
作者：
Woynarowski, JM;Chapman, WG;Juniewicz, P
奥沙利铂是一种临床抗癌药物，其药理特性不同于顺铂。我们的研究比较了奥沙利铂和顺铂分别在裸DNA和细胞内DNA中诱导的损伤的部位和区域特异性。用重复扩增法对裸猴病毒40(SV40DNA)中的奥沙利铂加合物进行了定位。奥沙利铂加合物与顺铂加合物的位置几乎相同，集中在G簇和GNG基序中，可能反映了链内的交联链。虽然特异性SV40片段的碱性琼脂糖凝胶电泳显示奥沙利铂形成了链间交联，但这种病变类型的水平很低。用聚合酶链式反应终止试验评估药物对人肿瘤细胞A2780细胞DNA不连续位点的损伤。200 mM奥沙利铂对人β-珠蛋白、c-myc、hprt基因和线粒体DNA的诱导作用分别与1300、1500、800和300个/10(6)碱基相似。顺铂在相同区域形成的皮损要多两到六倍。对于这两种药物，损伤频率似乎与核区药物结合基序的密度平行，而线粒体DNA受到的影响则不成比例地小。尽管对DNA损伤的诱导作用较弱，但奥沙利铂对A2780细胞的细胞毒作用强于顺铂。因为我们的发现清楚地表明，奥沙利铂形成的共价加合物具有与顺铂相似的序列和区域特异性，所以奥沙利铂加合物的其他性质、DNA结合以外的因素或两者共同决定了奥沙利铂作用机制的独特特征。
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 mu M induced similar to 1300, similar to 1500, similar to 800, and similar to 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.