MicroRNA-665 Regulated Cell Proliferation, Migration and Apoptosis by Targeting Nemo-like Kinase in Non-small Cell Lung Cancer

Background: Many evidences proved important roles of microRNAs in the occurrence and development of non-small cell lung cancer (NSCLC). This work aimed to explore the effects and regulating mechanism of microRNA-665 (miR-665) in NSCLC. Methods: Here, quantitative real time PCR was used to evaluate the expression level of miR-665 in NSCLC tissues and several cell lines (H520, H1299, PC9, H358, and A549). Then, MTT, apoptosis assays and wound-healing assays were performed to study miR-665 functions on cell proliferation, apoptosis and migration. Based on bioinformatics analysis, nemo-like kinase (NLK) was predicted as a potential target of miR-665 and then a series of experiments were performed to explore miR-665 mechanism.Results: In NSCLC tissues and several cell lines, miR-665 was up-regulated and cell experiments displayed that it had abilities to promote cell proliferation and migration, and inhibit cell apoptosis. MiR-665 over-expression could reduce NLK mRNA and protein level by binding to 3′-untranslated region of NLK, which suggested that miR-665 could regulate NLK expression. Further analysis found that there was an inverse correlation f between miR-665 and NLK in NSCLC. Moreover, low-level NLK possessed same effects on cells as miR-665 over-expression, and its knockdown could partly recovery the miR-665-mediated cell proliferation, migration and anti-apoptosis, indicating that miR-665 might regulate biological behaviors of NSCLC cells via targeting NLK. Conclusion: MiR-665 probably promoted NSCLC occurrence and progression via targeting NLK, which might be a hopeful biomarker for NSCLC diagnosis or a target for treatment.