MiR-372-3p promotes cell growth and metastasis by targeting FGF9 in lung squamous cell carcinoma

The aim of this study was to study the role of miR-372-3p in lung squamous cell carcinoma (LSCC) cell proliferation and invasion by suppressing FGF9. RT-PCR was used to determine miR-372-3p and FGF9 mRNA expression in tissues and cells. Western blot was used to determine FGF9 expression in tissues and NCI-H520 cell line. Dual luciferase reporter gene assay was conducted to confirm that FGF9 can be directly targeted by miR-372-3p. MTT, colony formation assays were conducted to investigate the effects of ectopic miR-372-3p and FGF9 expression on NCI-H520 cell growth. Flow cytometry was used to analyze the influence of miR-372-3p and FGF9 expression on cell cycle distribution and apoptosis. Transwell assay was also conducted to see the effects of miR-372-3p and FGF9 expression on NCI-H520 cell invasiveness. MiR-372-3p was found significantly overexpressed in both LSCC tissues and cell lines, whereas FGF9 mRNA was found underexpressed in LSCC tissues. MiR-372-3p directly bound to wild-type FGF9 mRNA 3'UTR, therefore led to the reduction in FGF9 expression. The upregulation of FGF9 or the downregulation of miR-372-3p substantially retarded LSCC cell growth, mitosis, and invasion. MiR-372-3p enhanced LSCC cell proliferation and invasion through inhibiting FGF9.