MiR-144 inhibits cell proliferation of renal cell carcinoma by targeting MTOR.

MicroRNAs (miRNAs) modulate the expression of tumorigenesis-related genes and play important roles in the development of various types of cancers. It has been reported that miR-144 is dysregulated and involved in multiple malignant tumors, but its role in renal cell carcinoma (RCC) remains elusive. In this study, we demonstrated miR-144 was significantly downregulated in human RCC. The decreased miR-144 correlated with tumor size and TNM stage. Moreover, overexpression of miR-144 in vitro suppressed RCC cell proliferation and G2 transition, which were reversed by inhibition of miR-144. Bioinformatic analysis predicted that mTOR was a potential target of miR-144, which was further confirmed by dual luciferase reporter assay. Additionally, the examination of clinical RCC specimens revealed that miR-144 was inversely related to mTOR. Furthermore, knocking down mTOR with siRNA had the same biological effects as those of miR-144 overexpression in RCC cells, including cell proliferation inhibition and S/G2 cell cycle arrest. In conclusion, our results indicate that miR-144 affects RCC progression by inhibiting mTOR expression, and targeting miR-144 may act as a novel strategy for RCC treatment.