Zhang X H, Zhang F Y, Ji X J, Li Z Y
Institute of Materia, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing.
Yao Xue Xue Bao. 1994;29(4):246-51.
A multidrug-resistant (mdr) clone of human cancer KB cells was isolated by stepwise selection on exposure to increasing doses of vincristine. The final clone, KBv200, obtained after ethylmethane sulfonate (EMS) mutagenesis showed 175-fold higher resistance to vincristine than did KB cells. The cells were also cross-resistant to taxol, colchicine and adriamycin. Cellular accumulation of vincristine in KBv200 was decreased to less than one-fifth of that in KB. To determine the presence of mdr 1 mRNA in KBv200 and KB, total cellular RNAs from each cell line were analyzed by means of slot blot hybridization. The result showed that the mdr 1 gene had been highly expressed in KBv200. In addition, verapamil, a calcium channel blockers, was shown to increase VCR accumulation in KBv200 and reverse the vincristine resistance. All these results demonstrate that the mechanism of KBv200 cell resistance to multiple drugs resulted from increased expression of mdr 1 gene and brought about over production of P-glycoprotein and increased the efflux of drugs.
通过逐步增加长春新碱剂量进行筛选，分离出了人癌KB细胞的多药耐药（mdr）克隆。经甲基磺酸乙酯（EMS）诱变后获得的最终克隆KBv200，对长春新碱的耐药性比KB细胞高175倍。这些细胞对紫杉醇、秋水仙碱和阿霉素也具有交叉耐药性。长春新碱在KBv200细胞中的蓄积量降至KB细胞中的五分之一以下。为了确定KBv200和KB细胞中mdr 1 mRNA的存在情况，通过狭缝印迹杂交分析了每个细胞系的总细胞RNA。结果表明，mdr 1基因在KBv200中高表达。此外，钙通道阻滞剂维拉帕米可增加KBv200中长春新碱的蓄积，并逆转其对长春新碱的耐药性。所有这些结果表明，KBv200细胞对多种药物的耐药机制是由于mdr 1基因表达增加，导致P-糖蛋白过度产生，药物外排增加。
