MiR-501-3p functions as a tumor suppressor in non-small cell lung cancer by downregulating RAP1A.

MicroRNA-501-3p (miR-501-3p) has been reported to play tumor-suppressive roles in different cancers; however, its expression pattern and biological function in non-small cell lung cancer (NSCLC) remain unknown. In this study, we noted downregulation of miR-501-3p in NSCLC tissues and cell lines. Functional assays showed that overexpression of miR-501-3p suppressed NSCLC cell proliferation, clonogenicity, migration, and invasion. Moreover, miR-501-3p overexpression attenuated in vivo tumor growth in a nude mouse model. In terms of the mechanism, RAP1A was identified as a novel target of miR-501-3p. Overexpression of RAP1A strongly attenuated the inhibitory effects of miR-501-3p on the capacity of NSCLC cells for proliferation and motility. In the clinical samples of NSCLC, miR-501-3p levels negatively correlated with RAP1A expression, which was upregulated in NSCLC. Collectively, these results indicate that miR-501-3p acts as a tumor suppressor in NSCLC by directly targeting RAP1A mRNA and may serve as a theranostic biomarker for patients with NSCLC.