Kotoh S, Naito S, Yokomizo A, Kumazawa J, Asakuno K, Kohno K, Kuwano M
Department of Urology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Cancer Res. 1994 Jun 15;54(12):3248-52.
We established three cis-diamminedichloroplatinum(II) (cisplatin)-resistant cell lines, T24/DDP5, T24/DDP7, and T24/DDP10, by the stepwise exposure of T24 human bladder cancer cells to increasing concentrations of cisplatin. The resistance to cisplatin of T24/DDP5, T24/DDP7, and T24/DDP10 cells was 2.2-, 5.2-, and 8.4-fold that of the parental T24 cells, respectively. The cisplatin-resistant cell lines also showed an increased resistance to vincristine, although their sensitivities to Adriamycin and etoposide resembled that of T24. In contrast, the cisplatin-resistant cells developed a collateral sensitivity to (4s)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino)carbonyl oxy]dione hydrochloride trithydrate, a camptothecin derivative, and its active metabolite, 7-ethyl-10-hydroxy-camptothecin, that targets DNA topoisomerase I. Both a Northern blot analysis and an immunoblot analysis demonstrated increased cellular levels of DNA topoisomerase I mRNA in the resistant cell lines. However, the expression of DNA topoisomerase II in the three resistant cell lines did not differ significantly from that in the T24 cells. No significant differences in the glutathione S-transferase pi levels were observed, although the intracellular content of glutathione in the T24/DDP7 cells was slightly but significantly increased. In addition, the intracellular platinum concentration correlated negatively with the degree of cisplatin resistance and was found to be significantly decreased in T24/DDP10 at an external cisplatin concentration of 20 micrograms/ml. These results suggest that the increased levels of DNA topoisomerase I mRNA thus play an important role in cisplatin resistance and produce a collateral sensitivity to (4s)-4,11-diethyl-4-hydroxy-9[(4-piperidinopiperidino)carbonylo xy]dione hydrochloride trithydrate and 7-ethyl-10-hydroxycamptothecin in these cisplatin-resistant bladder cancer cell lines. In addition, the presence of decreased intracellular cisplatin accumulation may also contribute to the acquisition of resistance to cisplatin in these cell lines.
我们通过将T24人膀胱癌细胞逐步暴露于浓度递增的顺铂中，建立了三种顺二氯二氨铂（II）（顺铂）耐药细胞系，即T24/DDP5、T24/DDP7和T24/DDP10。T24/DDP5、T24/DDP7和T24/DDP10细胞对顺铂的耐药性分别是亲代T24细胞的2.2倍、5.2倍和8.4倍。顺铂耐药细胞系对长春新碱的耐药性也有所增加，尽管它们对阿霉素和依托泊苷的敏感性与T24细胞相似。相比之下，顺铂耐药细胞对一种喜树碱衍生物盐酸三乙醇胺（4s）-4,11-二乙基-4-羟基-9-[(4-哌啶基哌啶基)羰基氧基]二酮三水合物及其活性代谢物7-乙基-10-羟基喜树碱产生了旁系敏感性，后者靶向DNA拓扑异构酶I。Northern印迹分析和免疫印迹分析均表明，耐药细胞系中DNA拓扑异构酶I mRNA的细胞水平有所增加。然而，三种耐药细胞系中DNA拓扑异构酶II的表达与T24细胞相比无显著差异。尽管T24/DDP7细胞中谷胱甘肽的细胞内含量略有但显著增加，但谷胱甘肽S-转移酶pi水平未观察到显著差异。此外，细胞内铂浓度与顺铂耐药程度呈负相关，发现在外部顺铂浓度为20微克/毫升时，T24/DDP10细胞中的细胞内铂浓度显著降低。这些结果表明，DNA拓扑异构酶I mRNA水平的增加在顺铂耐药中起重要作用，并在这些顺铂耐药膀胱癌细胞系中对盐酸三乙醇胺（4s）-4,11-二乙基-4-羟基-9-[(4-哌啶基哌啶基)羰基氧基]二酮三水合物和7-乙基-10-羟基喜树碱产生旁系敏感性。此外，细胞内顺铂积累的减少也可能有助于这些细胞系获得对顺铂的耐药性。
