MicroRNA-338-3p functions as a tumor suppressor in human nonsmallcell lung carcinoma and targets Ras-related protein 14

Abstract

microRNAs (miRNAs) have been demonstrated to be important gene regulators with critical roles in diverse biological processes, including tumorigenesis. Accumulating evidence suggests that miR338-3p exerts a tumor suppressor role and is downregulated in tumors, including gastric cancer and colorectal carcinoma. However, the role of miR338-3p in lung cancer, particularly nonsmallcell lung carcinoma (NSCLC), has remained elusive. In the present study, the expression levels of miR338-3p in NSCLC tissues were compared with those of matched normal tissues by use of polymerase chain reaction analysis. miR-338-3p was shown to be downregulated in NSCLC tissues, and the expression levels of miR3383p were significantly correlated with NSCLC cancer differentiation, pathological stage and lymphnode metastasis. Ectopic miR-338-3p expression significantly suppressed the in vitro proliferation and colony formation of NSCLC cells and enhanced apoptosis. Of note, ectopic miR338-3p expression significantly inhibited Rasrelated protein 14 (RAB14) mRNA and protein expression, and reduced luciferase reporter activity containing the RAB14 3'-untranslated region through the first binding site. These findings suggested that miR338-3p regulated the survival of NSCLC cells partially through the downregulation of RAB14. Therefore, targeting the miR338-3p/RAB14 interaction may serve as a novel therapeutic application to treat NSCLC patients.