miR-149 reverses cisplatin resistance of gastric cancer SGC7901/DDP cells by targeting FoxM1.

Drug resistance remains a major unresolved obstacle for gastric cancer (GC) treatment. Recently, increasing studies have showen that microRNAs (miRNAs) are involved in cancer chemotherapeutic resistance and can potentially be applied to reverse drug resistance in cancers. The relationship between miRNA-149 expression and cisplatin (DDP) resistance in GC cells is still unknown. Here, we detected miR-149 expression by using RT-PCR and found that expression of miR-149 was downregulated in SGC7901/DDP cells compared with SGC7901cells, indicating a role of miR-149 in determining cisplatin-resistance of GC cells. Then, SGC7901/DDP cells were tansfected with miR-149 mimics, MTT assay was performed to determine SGC7901/DDP cell viability, and showed that overexpression of miR-149 inhibited the cell viability after cisplatin treatment, suggesting that up-regulation of miR-149 enhanced SGC7901/DDP cell sensitivity to cisplatin. Furthermore, we confirmed that Forkhead box M1 (FoxM1) is a direct target of miR-149 in SGC7901/DDP cells by using luciferase reporter assay. Besides, we also demonstrated that miR-149 enhances SGC7901/DDP cell sensitivity to cisplatin by downregulating FoxM1 expression. In summary, our data provide new insights that miR-149 plays an important role in determining sensitivity of cisplatin-resistant GC cells by targeting FoxM1 and suggest that miR-149 could be a potential target for reversing drug resistance in GC.