MicroRNA-195 suppresses the progression of lung adenocarcinoma by directly targeting apelin.

Background Apelin plays an important role in many types of tumors. We aimed to identify the effects of miR-195 on inhibiting apelin and clarify the regulating mechanism of miR-195-apelin in lung adenocarcinoma cells. Methods We detected the expression levels of apelin and miR-195 in lung adenocarcinoma tissues and lung cancer cell lines using Western blotting and quantitative reverse transcription PCR assay, respectively. Luciferase reporter assay was used to confirm the target gene of miR-195. The effects of miR-195 and apelin on the proliferation and cell cycle of lung adenocarcinoma cells were assessed by methyl thiazolyl tetrazolium and colony formation assays, and flow cytometry. Wound-healing and transwell invasion experiments were employed to examine cellular migration and invasion. A tumor xenograft model was then used to investigate the role of miR-195 on tumor growth in vivo. Results The expression level of apelin and miR-195 showed an inverse correlation in lung adenocarcinoma tissues and cell lines. Luciferase reporter assay suggested that miR-195 directly targets apelin messenger RNA. Overexpression of miR-195 significantly inhibited the proliferation, migration, and invasion of lung adenocarcinoma cells in vitro and suppressed tumor growth in vivo. Further analysis revealed that apelin is one of the functional target genes of miR-195, and the overexpression of apelin efficiently inhibits the promotion of cell proliferation and invasion mediated by miR-195 mimics in lung adenocarcinoma cells. Conclusions Our data constitute evidence that miR-195 inhibits lung adenocarcinoma cell proliferation and invasion though targeting apelin and provides novel insight into the mechanism underlying the development of lung adenocarcinoma.