Antagonism of miRNA-21 Sensitizes Human Gastric Cancer Cells to Paclitaxel

The development of drug resistance has largely limited the clinical outcome of anti-cancer treatment. Recent work has highlighted the involvement of non-coding RNAs, microRNAs (miRNAs), in cancer development. The present study aimed to investigate the role of miR-21 in the development of drug resistance to paclitaxel in gastric cancer cells. Our study found that the expression of miR-21 upregulated in the paclitaxel resistant cell line SGC7901/paclitaxel compared to its parental line SGC7901. Moreover, over-expression of miR-21 significantly decreased antiproliferative effects and apoptosis induced by paclitaxel, while knockdown of miR-21 dramatically increased antiproliferative effects and apoptosis induction by paclitaxel. Moreover, our results demonstrated that miR-21 may modulate the sensitivity to PTX, at least in part, by regulating the expression of P-glycoprotein.