去甲斑蝥酸钠对耐顺铂肺腺癌A549／DDP细胞逆转的分子机制

目的探讨去甲斑蝥酸钠（SNCTD）对耐顺铂人肺腺癌细胞系A549／DDP的逆转作用及可能分子机制。方法（1）采用CCK法筛选出SNCTD对A549／DDP的无毒浓度（即对细胞抑制率〈10％的药物浓度），并检测出顺铂及与无毒浓度SNCTD联合对耐药细胞株的半数抑制浓度（IC50）；（2）采用流式细胞仪分别检测1、2倍无毒浓度SNCTD对细胞内罗丹明123的蓄积情况；（3）采用逆转录-多聚酶链反应（RT—PCR）检测1、2倍无毒浓度SNCTD处理细胞48h后耐药相关基因mdr1mRNA、MRP1mRNA、GST—PimRNA表达，并检测药物处理72h后GST—PimRNA的表达。结果（1）SNCTD对A549／DDP的无毒浓度为5μg／ml，无毒浓度SNCTD与顺铂联合应用可使A549／DDP细胞对顺铂的IC50值下降为4．32μg／ml，逆转倍数为1．97倍；（2）无毒浓度SNCTD处理耐药细胞48h后细胞内罗丹明123荧光强度明显增强（P〈0．05）；（3）5、10μg／ml SNCTD处理耐药细胞株48h后mdr1 mRNA、MRP1 mRNA表达均明显减弱（P〈0．05），而且10μg／ml SNCTD处理组减弱强度亦明显大干5μg／mlSNCTD处理组（P〈0.05），呈现浓度依赖性；而GST—PimRNA表达并无明显变化（P〉0．05），72h后GST—PimRNA表达也未出现下降（P〉0．05）。结论SNCTD可以逆转A549／DDP细胞的耐药作用。其作用机制可能与下调耐药相关基因mdr1、MRP1的表达，影响膜蛋白外排泵功能有关。

The reverse effect of sodium norcantharidate on human lung adenocarcinoma cell line A549/DDP

Objective To investigate the reverse effect and mechanism of sodium norcantharidate （SNCTD） on human lung adenocarcinoma cell line A549/DDP. Methods The innoxious concentration （less than 10 percent of cell inhibition ratio） of SNCTD was screened by CKK assay and IC50 of cisplatin was measured; the drug-resistant A549/DDP cells were treated with innoxious concentration of SNCTD with cisplatin. The accumulation effect of Rh123 were assayed by flow cytometry after treated with 1 and 2 folds non-toxic concentration of SNCTD for 48h. PT-PCR were used to detect the expression of mdrl, MRP1, GST-Pi genes for the drug-resistant cell line treated with 1 and 2 folds of innoxious concentration of SNCTD for 48h. GST-Pi gene was detected after treated with the drug for 72h again. Results The non-toxic concentration of SNCTD was 5 p g/ml. SNCTD decreased drug resistance to cisplatin with the reversal fold of 1.97. The fluorescence intensity of Rh123 in the cells treated with 5 p g/ml SNCTD was significantly increased （P 〈 0.05）. The expressions of mdrl and MRP1 gene were decreased significantly in a concentration dependent manner （P〈 0.05）; while the expression of GST-Pi gene was not changed （P〉 0.05）. Conclusion SNCTD can reverse the resistance to cisplatin in A549/DDP cell line, which may be associated with down-regulating the expression of mdrl and MRP1 genes and inhibiting the efflux pump function of membrane proteins.