RESUMEN
BACKGROUND: MicroRNAs (miRNAs) emerge as important regulators involved in malignant progression in some tumors. MiR-181a has been found to function as a tumor suppressor in some tumors including non-small cell lung cancer (NSCLC). However, the functional role of miR-181a in NSCLC still needed to be investigated. METHODS: The expression of miR-181a were determined by qRT-PCR, the association between miR-181a and clinicopathological data were performed by chi-square test and survival analysis were evaluated by Kaplan-Meier curve and log rank test. Cell proliferation and invasion were assessed by CCK8, cell colony formation and transwell assays. Luciferase reporter assay demonstrated that CDK1 was a target of miR-181a. Western blot assay detected the relative protein expression. RESULTS: In the study, our results showed that miR-181a was significantly down-regulated in non-small cell lung cancer (NSCLC) tissues and cell lines. MiR-181 expression levels were significantly associated with histological grade, N status and TNM stage in the patients and lower miR-181a predicted a poor prognosis in NSCLC patients. Furthermore, upregulation of miR-181a significantly suppressed the NSCLC cell proliferation, colony formation, and cell invasion capacities. Moreover, upregulation of miR-181a inhibited CyclinB1 and CyclinD1 expression in NSCLC cells. Luciferase activity assay results demonstrated CDK1 was a direct target of miR-181a and miR-181a inhibited cell proliferation by regulating the mRNA and protein levels of CDK1 in NSCLC cells. CONCLUSION: These data suggested that miR-181a plays a tumor suppressor and may be a potential therapeutic target for NSCLC patients.