Yu D S, Chang S Y, Ma C P
Department of Surgery, Tri-Service General Hospital, National Defence Medical Centre, Taipei, Taiwan, Republic of China.
Br J Urol. 1998 Feb;81(2):234-40. doi: 10.1046/j.1464-410x.1998.00518.x.
To characterize in vitro drug-induced multidrug resistance (MDR) in transitional cell carcinoma (TCC) cell lines, and to elucidate the possible mechanisms of acquired MDR and their modulation.
Two drug-resistant cell lines, TCC8702/A1000 (adriamycin 1000 ng/mL) and TCC8803/A200 (adriamycin 200 ng/mL), were established after long-term adriamycin treatment for at least 16 months. Their biological characteristics, including growth morphology, doubling time and cell cycle, were analysed. The drug-resistance pattern to various anticancer drugs was measured using a microplate cytotoxicity assay. The modulation of drug sensitivity by calcium-channel blockers and protein kinase C inhibitor was assessed among the different cancer cell lines.
Both MDR sublines had lower growth rates, lower saturation densities and higher nuclear/cytoplasmic ratios than the parent cell lines. DNA staining and cell cycle analysis revealed that both TCC8702/A1000 and TCC8803/A200 cells had a decreased S-phase fraction and the TCC8803/A200 cells a changed stem line; both sublines showed increased expression of membranous glycoprotein gp-170. The cytoplasmic content of glutathione and glucose-6-phosphate dehydrogenase were not related to the MDR development in the sublines. The drug-resistance index of TCC8702/A1000 to adriamycin was 121-fold higher than the native cell line and TCC8803/A200 was 189-fold higher. TCC8803/A200 also had a broader MDR to cisplatin, vinblastine and vincristine. Calcium-channel blockers (verapamil, quinidine) and protein kinase C inhibitors (tamoxifen) inhibited gp-170 activity and slowed the drug-efflux pump, with the acquired-MDR cells subsequently accumulating anticancer drugs. A calcium antagonist-based combination of modulators all presented synergistic cytotoxic enhancement of the anticancer drugs. Parent TCC cell lines had a poorer response to modulator treatment than their MDR sublines.
Different MDR mechanisms and subsequent modulator responses exist between native and acquired drug resistance in TCC cells. Acquired MDR seems strongly related to increased gp-170 expression and responds well to calcium antagonists. This phenomenon may be applicable in clinical conditions.
对移行细胞癌（TCC）细胞系中的体外药物诱导多药耐药（MDR）进行表征，并阐明获得性MDR的可能机制及其调节。
通过至少16个月的长期阿霉素处理建立了两个耐药细胞系，TCC8702/A1000（阿霉素1000 ng/mL）和TCC8803/A200（阿霉素200 ng/mL）。分析了它们的生物学特性，包括生长形态、倍增时间和细胞周期。使用微孔板细胞毒性试验测量对各种抗癌药物的耐药模式。评估了钙通道阻滞剂和蛋白激酶C抑制剂在不同癌细胞系中对药物敏感性的调节作用。
与亲代细胞系相比，两个MDR亚系的生长速率均较低，饱和密度较低，核/质比更高。DNA染色和细胞周期分析显示，TCC8702/A1000和TCC8803/A200细胞的S期比例均降低，且TCC8803/A200细胞的干细胞系发生改变；两个亚系均显示膜糖蛋白gp-170表达增加。谷胱甘肽和葡萄糖-6-磷酸脱氢酶的细胞质含量与亚系中的MDR发展无关。TCC8702/A1000对阿霉素的耐药指数比天然细胞系高121倍，TCC8803/A200高189倍。TCC8803/A200对顺铂、长春碱和长春新碱也具有更广泛的MDR。钙通道阻滞剂（维拉帕米、奎尼丁）和蛋白激酶C抑制剂（他莫昔芬）抑制gp-170活性并减缓药物外排泵，随后获得性MDR细胞积累抗癌药物。基于钙拮抗剂的调节剂组合均呈现出抗癌药物协同细胞毒性增强作用。亲代TCC细胞系对调节剂治疗的反应比其MDR亚系差。
TCC细胞中天然耐药和获得性耐药之间存在不同的MDR机制及随后的调节剂反应。获得性MDR似乎与gp-170表达增加密切相关，并且对钙拮抗剂反应良好。这种现象可能适用于临床情况。
