重组腺病毒介导MRP反义RNA逆转人肝癌细胞多药耐药表型的体外实验研究

Reversal of the multidrug resistance in human hepatocellular carcinoma cells by recombinant adenoviral delivery of the MRP antisense RNA in vitro

目的探讨重组腺病毒介导的多药耐药相关蛋白(MRP)反义RNA对阿霉素诱导的人肝癌耐药细胞株SMMC-7721/ADM多药耐药表型的体外逆转作用。方法应用自行构建的携带反义MRP的重组腺病毒(Ad-Asm rp),在体外转染人肝癌耐药细胞,测定转染后细胞对阿霉素(ADM)及柔红霉素(DNR)的半数致死量(IC50)并计算耐药倍数(RF值);在转染后不同时间点用流式细胞仪动态测定细胞对DNR摄取的变化及细胞膜表面P190表达、并用RT-PCR反映细胞MRP之mRNA水平的变化。结果携带MRP反义RNA的重组腺病毒转染后的人肝癌耐药细胞对ADM、DNR的IC50分别为0.487μg/m l、0.328μg/m l,RF值分别为97.4、109.3,RF值分别下降36.8和35.4。在转染后24 h,MRP mRNA水平开始下降并呈持续下降趋势(P<0.01),48 h后伴有P190蛋白表达的持续下降(P<0.01),二者趋势一致。转染后48 h,经流式细胞仪测得细胞内DNR浓度明显上升(P<0.01)。结论重组腺病毒介导的MRP反义RNA可有效封闭MRP基因表达,在体外实验中能增加人肝癌耐药细胞株对化疗药物的敏感性,对肝癌耐药细胞的MDR表型有较好的逆转作用。

Objective To investigate the effects of multidrug resistance-associated protein （MRP） antisense RNA mediated by recombinant adenoviruses on reversal of the multidrug resistance （MDR） in human drug-resistant hepatocellular carcinoma （HCC） cells. Methods HCC cells of the line SMMC-7721/ ADM were cultured in a 96-well-plate and transfected with recombinant adenovirus Ad-ASmrp containing antisense MRP. Another SMMC-7721/ADM cells were transfected with Ad-GFP or added with PBS were used as controls. The cells were collected from 3 wells everyday for 7 days to observe the absorbance so as to draw a growth curve. SMMC-7721/ADM cells were transfected with Ad-ASmrp and Ad-GFP, added with adriamycin （ADM） or daunorubicin （DNR） , and then cultured for 48 hours. The chemosensitivity of the cells to ADM and DNR was determined by MTT assay. The levels of MRP mRNA and its product P190 were measured by RT-PCR and flow cytometry （FCM） 24, 48, 72, 96, and 120 hours after respectively. The accumulation of DNR in these cells was analyzed by FCM simultaneously. Results The IC50 values of the cells transfected with Ad-Asmrp to ADM and DNR were 0.487 μg/ml and 0.328μ g/ml , and the factors of resistance （RF） decreased by 36.8 and 35.4 respectively （both P 〈 0.05 ）. Continuous decrease in levels of MRP mRNA and P190 was observed 24 h and 48h after transfection respectively （both P 〈 0.01 ）. The intracellular DNR accumulation was increased simultaneously in the Ad-Asmrp transfected cells （P 〈 0.01 ）. Conclusions MRP antisense RNA mediated by recombinant adenovirus increases chemosensitivity and partially reverses the MDR in HCC cells in vitro by inhibiting the expression of MRP gene.