Salles B, Calsou P, Bouayadi K, Vinial H
Laboratoire de Pharmacologie et Toxicologie Fondamentales du Centre National de la Recherche Scientifique (CNRS), Toulouse, France.
Toxicology. 1994 Nov 11;93(2-3):235-47. doi: 10.1016/0300-483x(94)90081-7.
The mechanisms underlying cellular resistance to the antitumor drug cis-diamminedichloro-platinum(II) (CDDP) were studied in Escherichia coli K12. A bacterial strain (MC4100/DDP) was selected from the MC4100 wild-type strain after growth for four cycles in CDDP. MC4100/DDP bacteria showed a high level of resistance and exhibited various modifications including (1) a decrease in drug uptake and platinum/DNA binding which only partly contributed to resistance, (2) an increase in glutathione content not involved in the resistant phenotype, (3) an increase in DNA repair capacity. Resistance was unmodified by introducing a uvrA mutation which neutralizes the excision-repair pathway. In contrast, it was abolished by deletion of the recA gene which abolishes recombination and SOS repair but also by a mutation in the recA gene leading to RecA co-protease minus (no SOS induction). RecA protein was unchanged in MC4100/DDP but the expression of RecA-dependent gene(s) was required for CDDP resistance. The regulation of genes belonging to the SOS regulon was analysed in MC4100/DDP by monitoring the expression of sfiA and recA::lacZ gene fusions after UV irradiation. These gene fusions were derepressed faster and the optimal expression was obtained for a lower number of UV lesions in MC4100/DDP, suggesting a role of RecA co-protease activity in the mechanism of resistance to CDDP in this E. coli strain.
在大肠杆菌K12中研究了细胞对抗肿瘤药物顺二氨二氯铂（II）（CDDP）产生抗性的机制。在CDDP中生长四个周期后，从MC4100野生型菌株中筛选出一个细菌菌株（MC4100/DDP）。MC4100/DDP细菌表现出高水平的抗性，并呈现出多种变化，包括：（1）药物摄取和铂/DNA结合减少，这仅部分导致抗性；（2）谷胱甘肽含量增加，但与抗性表型无关；（3）DNA修复能力增强。引入uvrA突变使切除修复途径失活，抗性未改变。相反，recA基因缺失会消除重组和SOS修复，从而消除抗性，recA基因突变导致RecA共蛋白酶缺失（无SOS诱导）也会消除抗性。MC4100/DDP中的RecA蛋白未发生变化，但CDDP抗性需要RecA依赖性基因的表达。通过监测紫外线照射后sfiA和recA::lacZ基因融合体的表达，分析了MC4100/DDP中属于SOS调节子的基因调控。在MC4100/DDP中，这些基因融合体去阻遏更快，且在较少数量的紫外线损伤时就能获得最佳表达，这表明RecA共蛋白酶活性在该大肠杆菌菌株对CDDP的抗性机制中发挥作用。
