Perego P, Zunino F, Carenini N, Giuliani F, Spinelli S, Howell S B
Department of Experimental Oncology B, Istituto Nazionale per lo Studio e la Cura dei Tumori, 20133 Milan, Italy.
Mol Pharmacol. 1998 Jul;54(1):213-9. doi: 10.1124/mol.54.1.213.
The role of genes that affect response to radiation in determining sensitivity to platinum-containing compounds was studied using a panel of 23 strains of the yeast Schizosaccharomyces pombe. The radiation-hypersensitive mutants all had the same genetic background and most of them contained mutations that disabled either cell cycle checkpoints or DNA repair. The tested platinum compounds included cisplatin and two complexes containing diaminocyclohexane (oxaliplatin and tetraplatin), two ammine/cyclohexylamine complexes with different orientation of the leaving groups (JM216 and JM335) and a multinuclear platinum complex (BBR 3464). The cytotoxic effect of the selected platinum complexes was evaluated by using a microtiter growth inhibition assay with a 48 hr exposure to drug. The mutants fell into three groups with respect to sensitivity to cisplatin: four mutants (rad2, -7, -11, -15) exhibited minimal change in sensitivity; fifteen mutants (rad4-6, -8-10, -12-14, -16-17, -19-21, and -22) were 5.1-21.7-fold hypersensitive; only rad1 and -3 mutants, defective in checkpoints, and rad18, defective in repair, displayed a marked hypersensitivity. None of the mutants demonstrated appreciable change in sensitivity to JM216 presumably as a consequence of a lack of resistance of the wild-type strain, whereas a moderate increase in sensitivity to JM335 was observed for most of the mutants, and hypersensitivity to BBR3464 was observed only in rad1 and -3. No relevant changes in sensitivity to tetraplatin were observed. Most of the mutants, with the exception of rad2, -7, and -15, were hypersensitive to oxaliplatin. These findings demonstrate that specific mutations have disparate effects on the profile of sensitivity to different members of the same class of cytotoxic agents, which provides genetic evidence that different mechanisms are involved in differential cytotoxicity induced by Pt compounds. The results also demonstrate the utility of such a panel of mutants, constructed on the same genetic background, for detecting specific cellular response; presumably, this reflects the recognition or processing of specific DNA adducts. In conclusion, because the rad1 and rad3 gene products are determinants of cellular response to a large number of platinum-containing compounds, the present results support a critical role of genes involved in cell cycle control in cellular sensitivity to these agents.
利用一组23株粟酒裂殖酵母研究了影响辐射反应的基因在决定对含铂化合物敏感性方面的作用。辐射敏感突变体均具有相同的遗传背景，其中大多数含有使细胞周期检查点或DNA修复功能丧失的突变。所测试的铂化合物包括顺铂和两种含二氨基环己烷的配合物（奥沙利铂和四铂）、两种离去基团取向不同的氨/环己胺配合物（JM216和JM335）以及一种多核铂配合物（BBR 3464）。通过使用微量滴定生长抑制试验评估所选铂配合物的细胞毒性作用，药物暴露48小时。就对顺铂的敏感性而言，突变体分为三组：四个突变体（rad2、-7、-11、-15）的敏感性变化最小；十五个突变体（rad4-6、-8-10、-12-14、-16-17、-19-21和-22）的敏感性高5.1-21.7倍；只有检查点缺陷的rad1和-3突变体以及修复缺陷的rad18突变体表现出明显的高敏感性。由于野生型菌株缺乏抗性，没有突变体对JM216的敏感性表现出明显变化，而大多数突变体对JM335敏感性适度增加，仅rad1和-3对BBR3464表现出高敏感性。未观察到对四铂敏感性的相关变化。除rad2、-7和-15外，大多数突变体对奥沙利铂敏感。这些发现表明，特定突变对同一类细胞毒性药物不同成员的敏感性谱有不同影响，这提供了遗传证据，表明铂化合物诱导的差异细胞毒性涉及不同机制。结果还证明了在相同遗传背景下构建的这样一组突变体在检测特定细胞反应方面的实用性；据推测，这反映了对特定DNA加合物的识别或处理。总之，由于rad1和rad3基因产物是细胞对大量含铂化合物反应的决定因素, 目前的结果支持参与细胞周期控制的基因在细胞对这些药物的敏感性中起关键作用。
