MiR-431 suppresses proliferation and metastasis of lung cancer via down-regulating DDX5

We aimed to detect the role and function of microRNA-431 (miR-431) in lung cancer, and to investigate the underlying mechanism in regulating the development of lung cancer.

Quantitative Real-time polymerase chain reaction (qRT-PCR) was utilized to measure the relative expression level of miR-431 in lung cancer tissues and cell lines. Cell counting kit-8 (CCK-8) and colony formation assays were employed to measure the proliferative ability of lung cancer cells. Meanwhile, transwell assay was recruited to detect the invasive and migratory abilities of lung cancer cells. Furthermore, dual-luciferase reporter gene assay was designed to verify the target gene of miR-431. Western blot assay was used to gauge the protein level of DDX5 (DEAD box polypeptide 5).

MiR-431 expression was significantly lower in 122 lung cancer tissue samples or cell lines compared to the adjacent normal tissues or lung bronchial epithelial cell line, respectively. Over-expression of miR-431 significantly inhibited proliferation, invasion and migration of A549 cells. Down-regulation of miR-431 accelerated cell growth and metastasis of H1650 cells. DDX5 was proved to be a direct target for miR-431 in lung cancer.

MiR-431 expression decreased in lung cancer tissues and cells. MiR-431 suppressed proliferation, invasion and migration of lung cancer cells via inhibiting the expression of DDX5. Our study might provide a novel target for the biological therapy of lung cancer.