miR-181a suppresses autophagy and sensitizes gastric cancer cells to cisplatin

• miR-181a inhibited autophagy in cisplatin-resistant cell line SGC7901/CDDP.
• ATG5 was a potential target of miR-181a.
• miR-181a sensitized SGC7901/CDDP cells to cisplatin in vivo and in vitro.

A number of chemotherapy drugs can induce autophagy. This inducible autophagy is a pro-survival mechanism and contributes to the development of acquired drug resistance. Emerging evidence indicates that miRNA regulates autophagy via targeting autophagy related genes and is involved in drug resistance. We previously demonstrated that miR-181a plays an important role in gastric cancer. The present study aimed to explore the effect of miR-181a on autophagy regulation and cisplatin resistance. We revealed that miR-181a is a novel negative regulator of autophagy in cisplatin-resistant cells SGC7901/CDDP. Then we indicated that ATG5 was a potential target of miR-181a. Furthermore, overexpression of miR-181a significantly enhanced the sensitivity of SGC7901/CDDP cells to cisplatin in vitro and reduced the volumes of gastric tumor xenografts in nude mice. Our finding provides evidence that miR-181a functions as a primary autophagy-related modulator and reverses cisplatin-resistance in GC cells.