中文摘要：

目的：探讨RNA干扰技术（RNAi）对慢性粒细胞白血病急变细胞系K562／AO2细胞mdrl基因的抑制和耐药表型的逆转作用。方法：选择合成封闭mdr-1基因的小干扰序列（si-MDR1），以1个碱基突变的si—MDR1-mut为对照序列，在脂质体介导下转染至K562／AO2细胞系。RT—PCR和Western blot检测mdrl mRNA及p-gP蛋白水平，流式细胞术分析细胞内柔红霉素（daunorubiein，DNR）积累量，并以四甲基唑蓝快速比色法（MTT）反映K562／AO2对阿霉素、长春新碱、足叶乙甙药物敏感性的变化。结果：实验证实该序列能高效封闭K562／AO2细胞内mdr-1基因表达，增加细胞内化疗药物DNR积累量，增强K562／AO2细胞对阿霉素、长春新碱、足叶乙甙的敏感性。结论：RNAi可以通过抑制mdrl基因表达，逆转K562／AO2细胞耐药表型。

英文摘要：

Objective： To study the effect of RNA interference on expression of mdrl gene and multidrug resistance phenotype in chronic myeloid leukemia-blastic crisis K562/AO2 cells. Methods： MDRl-targeted small interfering RNA （si-MDR1） was selectively synthesized. Si-MDR1 with a single-base-pair mutation was used as control （si-MDRl-mut）. They were transferred into K562/AO2 cells mediated by liposome oligofectamine. The levels of mdrl mRNA and P-gp protein were detected by RTPCR and Western blotting, respectively. Daunorubicin （DNR） accumulation was analyzed by flow cytometry analysis. Sensitivities of K562/AO2 cells to adriamycin （ADM）, vincristine （VCR）, and etoposide （VP-16） were detected by MTT assay. Resalts： Mdrl-targeted small interfering RNA duplex effectively interfered with the expression of mdrl and inhibited P-gp protein expression in drug-resistant leukemia K562/AO2 cells, increased intracellular DNR accumulation, and enhanced chemosensitivity of K562/AO2 cells to ADM, VCR, and VP-16 . Conclusion： RNA interference reversed multidrug resistance phenotype of K562/AO2 cells via inhibition of mdr-1 gene expression.