MicroRNA-140 inhibits tumor progression in nasopharyngeal carcinoma by targeting CXCR4.

Recent evidence has indicated that miRNAs play important roles in carcinogenesis. The identification of dysregulated miRNAs and the target genes they regulate might enhance our understanding of the molecular mechanisms of nasopharyngeal carcinoma (NPC). microRNA-140 (miR-140) has been found to be down-regulated in cancer. However its role in nasopharyngeal carcinoma remains unclear. CXCR4 was predicted to be the target gene of miR-140. The current research was designed to delineate the mechanism of miR-140 in regulating NPC via targeting CXCR4. In this study, miR-140 was underexpressed in NPC tissues and cell lines compared with their normal controls and the biological function and direct target genes of miR-140 in NPC cells were investigated. Importantly, we demonstrate that the over expression of miR-140 significantly inhibits NPC cell proliferation and induces apoptosis. Additionally, CXCR4 was predicted the target gene of miR-140 and the luciferase reporter assay revealed that miR-140 was directly bound to the 3'-UTR of CXCR4. Furthermore, CXCR4 was inversely correlated with the expression of miR-140 in NPC cells. Taken together, our results suggest miR-140 suppresses tumor proliferation and induces apoptosis by inhibiting CXCR4, which might provide a new insight into the molecular mechanisms that regulate the development and progression of NPC, and it provides novel therapeutic targets for NPC.