MicroRNA-224, negatively regulated by c-jun, inhibits growth and epithelial-to-mesenchymal transition phenotype via targeting ADAM17 in oral squamous cell carcinoma

Abnormal expression of miR-224 has been reported to promote cancer progression. However, the role of miR-224 is seldom reported in oral squamous cell carcinoma (OSCC). We reported that miR-224 expression was significantly down-regulated in OSCC tissues and cell lines. Restoration of miR-224 decreased OSCC cell growth and invasion. In addition, luciferase and Western blot assays revealed that ADAM17 protein was a downstream target of miR-224. The overexpression of ADAM17 dismissed miR-224's effect on cell growth and invasion. We concluded that miR-224 inhibited OSCC cell growth and invasion through regulating ADAM17 expression. Subsequently, we revealed that c-jun directly bind to miR-224 promoter and decreased miR-224 expression. Taken together, these findings demonstrated that miR-224 may function as a tumour-suppressive microRNA in OSCC and suggested that miR-224 may be a potential therapeutic target for OSCC patients.