Lai S L, Hwang J, Perng R P, Whang-Peng J
Institute of Clinical Medicine, National Yang-Ming University, Taiwan, Taipei, Republic of China.
Oncol Res. 1995;7(1):31-8.
To obtain cisplatin (CDDP)-resistant cells possessing the clinically induced resistance phenotype, H-460 nonsmall cell lung cancer cells (NSCLC) were pulse treated with 20, 60, 80 microM CDDP for 1 h every week, respectively. Twelve months later, three CDDP-resistant cell lines (H-460/CDDP20, H-460/CDDP60, H-460/CDDP80) were obtained that exhibit different levels of CDDP resistance (6- to 22-fold), and the possible mechanisms of resistance were studied. These resistant cells were cross-resistant to carboplatin and melphalan, but not to adriamycin or 5-fluorouracil. CDDP resistance in these cell lines appeared to be stable even after 6 months of growth in cisplatin-free medium. There was no evidence of drug accumulation differences between parental and resistant cells. Although both intracellular glutathione (GSH) content and glutathione S-transferase (GST) activity increased 1.5- to 2.5-fold in the resistant cells, only a minimal reversal of drug resistance was observed after buthionine sulfoximine (BSO) treatment, which depleted intracellular GSH levels. An enhancement of DNA repair activity was found in the resistant cell lines and played the major role in the cisplatin resistance phenotype. Using H-460/CDDP80 cells as a model, addition of a nontoxic concentration of pentoxifylline (PTX) significantly enhanced CDDP-induced cytotoxicity in a synergistic manner. Furthermore, more prominent reversal of CDDP resistance could be achieved when the resistant cells were pretreated with BSO, followed by PTX and CDDP combined treatment. This provides a rationale for combination therapy in refractory lung cancer using CDDP and two resistance modulators.
为获得具有临床诱导耐药表型的顺铂（CDDP）耐药细胞，分别每周用20、60、80微摩尔/升的CDDP对H-460非小细胞肺癌细胞（NSCLC）进行1小时的脉冲处理。十二个月后，获得了三种CDDP耐药细胞系（H-460/CDDP20、H-460/CDDP60、H-460/CDDP80），它们表现出不同程度的CDDP耐药性（6至22倍），并对耐药的可能机制进行了研究。这些耐药细胞对卡铂和美法仑具有交叉耐药性，但对阿霉素或5-氟尿嘧啶不耐药。即使在无顺铂培养基中生长6个月后，这些细胞系中的CDDP耐药性似乎仍然稳定。亲本细胞和耐药细胞之间没有药物蓄积差异的证据。尽管耐药细胞中细胞内谷胱甘肽（GSH）含量和谷胱甘肽S-转移酶（GST）活性均增加了1.5至2.5倍，但在使用丁硫氨酸亚砜胺（BSO）处理耗尽细胞内GSH水平后，仅观察到耐药性的最小逆转。在耐药细胞系中发现DNA修复活性增强，并且在顺铂耐药表型中起主要作用。以H-460/CDDP80细胞为模型，添加无毒浓度的己酮可可碱（PTX）以协同方式显著增强了CDDP诱导的细胞毒性。此外，当耐药细胞先用BSO预处理，然后进行PTX和CDDP联合处理时，可以实现更显著的CDDP耐药逆转。这为使用CDDP和两种耐药调节剂联合治疗难治性肺癌提供了理论依据。
