Ye Xueshi, Liu Ting, Gong Yuping, Zheng Bohui, Meng Wentong, Leng Yamei
Department of Hematology, Hematology Research Laboratory, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan Province, China.
Leuk Res. 2009 Aug;33(8):1114-9. doi: 10.1016/j.leukres.2008.10.011. Epub 2008 Nov 26.
Multidrug-resistance (MDR) is a major hindrance to successful chemotherapy. The emergence of MDR is multi-factorial. Among them, the MDR1 gene/P-glycoprotein (P-gp) is a popular and important reason. In our study, an MDR1 single-factorial drug-resistant leukemia cell line K562/MDR1 was constructed via transferring full-length human MDR1 cDNA into drug-sensitive K562 cells. The short-hairpin RNA (shRNA) targeting MDR1 gene was transfected into K562/MDR1 cell lines by the replication-defective lentiviral vector derived from HIV-1. The efficiency of RNA interference (RNAi) to silence the MDR1 gene and reverse multidrug-resistance in the MDR1 single-factor drug-resistance cell line K562/MDR1 was evaluated. The multi-factor resistant cell line K562/A02, induced by doxorubicin exposure, was used as a control. After RNA interference, the expression of the MDR1 gene and P-gp in K562/MDR1 was markedly down-regulated and the drug sensitivity was restored as IC(50) values became similar to the K562 sensitive cell line. The expression of the MDR1 gene and P-gp in K562/A02 was markedly down-regulated too, and drug-resistance to anticancer drug is reduced to some extent but the IC(50) was significantly higher than that of the sensitive cell line. These results demonstrated that lentivirus-mediated RNAi could efficiently down-regulate the expression of MDR1 and Pgp, and successfully reverse a cell's resistance to chemotherapeutic. Due to only MDR1 resistance, the K562/MDR1 cell showed much high specificity and thus is a better cell model for MDR1/P-gp research.
多药耐药（MDR）是成功进行化疗的主要障碍。MDR的出现是多因素的。其中，MDR1基因/ P-糖蛋白（P-gp）是一个常见且重要的原因。在我们的研究中，通过将全长人MDR1 cDNA转入药物敏感的K562细胞中，构建了MDR1单因素耐药白血病细胞系K562 / MDR1。通过源自HIV-1的复制缺陷型慢病毒载体，将靶向MDR1基因的短发夹RNA（shRNA）转染到K562 / MDR1细胞系中。评估了RNA干扰（RNAi）沉默MDR1基因并逆转MDR1单因素耐药细胞系K562 / MDR1中的多药耐药性的效率。将由阿霉素暴露诱导的多因素耐药细胞系K562 / A02用作对照。RNA干扰后，K562 / MDR1中MDR1基因和P-gp的表达明显下调，药物敏感性得以恢复，因为IC（50）值变得与K562敏感细胞系相似。K562 / A02中MDR1基因和P-gp的表达也明显下调，对抗癌药物的耐药性在一定程度上降低，但IC（50）明显高于敏感细胞系。这些结果表明，慢病毒介导的RNAi可以有效下调MDR1和Pgp的表达，并成功逆转细胞对化疗的耐药性。由于仅存在MDR1耐药性，K562 / MDR1细胞具有很高的特异性，因此是用于MDR1 / P-gp研究的更好的细胞模型。
