Olivero O A, Semino C, Kassim A, Lopez-Larraza D M, Poirier M C
Laboratory of Cellular Carcinogenesis and Tumor Promotion, NIH, National Cancer Institute, Bethesda, MD 20892, USA.
Mutat Res. 1995 Apr;346(4):221-30. doi: 10.1016/0165-7992(95)90039-x.
Some chemical carcinogens localize preferentially in mitochondrial DNA (mtDNA) when compared with genomic DNA (gDNA). Here we compare the ability of cisplatin (cis-diamminedichloroplatinum[II]) to induce DNA adducts in both genomic and mtDNA of Chinese hamster ovary (CHO) cells in culture. Cytotoxicity was examined by cell survival 4, 8 and 24 h after exposure to 50 microM cisplatin. Cisplatin-DNA adducts were measured in DNA from nuclear and mitochondrial fractions by dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA), a sensitive competitive microtiter-based immunoassay utilizing antiserum elicited against cisplatin-modified DNA. An additional comparison of cisplatin-DNA binding in both compartments was performed by immunoelectron microscopy using the cisplatin-DNA antiserum and colloidal gold. DELFIA analysis of cisplatin-DNA adducts in gDNA and mtDNA showed a six-fold higher incorporation of drug into mtDNA as compared to gDNA. Morphometric studies of colloidal gold distribution in photomicrographs of CHO cells showed mtDNA to contain a four-fold higher concentration of cisplatin as compared to nuclear DNA. Therefore, both methods demonstrated a preferential binding of cisplatin to mtDNA versus gDNA.
与基因组DNA（gDNA）相比，一些化学致癌物优先定位于线粒体DNA（mtDNA）中。在此，我们比较了顺铂（顺二氨二氯铂[II]）在培养的中国仓鼠卵巢（CHO）细胞的基因组和mtDNA中诱导DNA加合物的能力。在暴露于50 microM顺铂后4、8和24小时，通过细胞存活情况检测细胞毒性。通过解离增强镧系荧光免疫分析（DELFIA）测量核和线粒体组分DNA中的顺铂-DNA加合物，这是一种基于微孔板的灵敏竞争免疫分析，利用针对顺铂修饰DNA产生的抗血清。使用顺铂-DNA抗血清和胶体金通过免疫电子显微镜对两个区室中的顺铂-DNA结合进行了额外比较。对gDNA和mtDNA中顺铂-DNA加合物的DELFIA分析显示，与gDNA相比，药物掺入mtDNA的量高六倍。对CHO细胞显微照片中胶体金分布的形态计量学研究表明，与核DNA相比，mtDNA中顺铂的浓度高四倍。因此，两种方法均表明顺铂与mtDNA的结合优于与gDNA的结合。
