MiR-193a-3p is an Important Tumour Suppressor in Lung Cancer and Directly Targets KRAS.

MicroRNAs (miRNAs) have emerged as major regulators of tumour development and progression in non-small cell lung cancer (NSCLC). However, the role of miR-193a-3p in NSCLC is still unclear. Quantitative RT-PCR was used to detect miR-193a-3p expression levels in NSCLC tumour tissues. CCK8, EdU and cell migration assays were performed to analyse the biological functions of miR-193a-3p in NSCLC cells. Luciferase reporter assays were used to validate the bioinformatics-predicted target genes of miR-193a-3p. Western blotting and RNA/DNA interference carried out to evaluate the association between miR-193a-3p and KRAS. miR-193a-3p expression was decreased in the NSCLC tumour tissues. We investigated the biological effects of miR-193a-3p both in vivo and in vitro and found that enforced expression of miR-193a-3p inhibited tumour formation and suppressed cell proliferation and cell migration. KRAS was found to be a potential target of miR-193a-3p, and dual luciferase reporter assays showed that miR-193a-3p directly binds to the 3'-untranslated region (3'-UTR) of KRAS mRNA. In addition, we found that changing the expression of KRAS had the opposite results to those induced by miR-193a-3p in the NSCLC cells. Importantly, simultaneous overexpression of miR-193a-3p and KRAS could counteract the effects of both on cellular functions. These findings highlight an important role for miR-193a-3p as a tumour suppressor in NSCLC pathogenesis via the regulation of KRAS expression.