Objective To investigate the effects of microRNA-18a(miR-18a) on migration and invasion of hepatocellular carcinoma(HCC) cells,and its possible mechanism associated with Dicer l. Methods HepG 2 and HepG 2.2.15 cells were transfected with miR-18 a inhibitor using Lipofectamine. Cell invasion was evaluated by transwell invasion assay,and cell migration was detected by transwell migration and wound-healing assays. Moreover,luciferase reporter assay was used to identify whether Dicer expression was regulated by miR-18 a. Real-time RT-PCR and western blot were performed to analyze Dicer 1 expression. In addition,a functional restoration assay was performed to investigate whether miR-18 a promotes HCC cell migration and invasion by directly targeting Dicer 1. Results miR-18 a inhibitor can suppress the migration and invasion of HCC cells. Furthermore,suppression of Dicer l expression by small interfering RNA essentially abolished the inhibition of cell migration and invasion induced by miR-18 a inhibitor,restorating these activities to levels similar to the parental HCC cells. Interestingly,suppression of miR-18 a in HCC cells resulted in enhanced expression of Dicer l. In addition,the results of a luciferase assay demonstrated targeted regulation of Dicer l by miR-18 a. Conclusion Our findings suggest that miR-18 a promotes migration and invasion of HCC cells by inhibiting Dicer l expression. Objective To investigate the effects of microRNA-18a (miR-18a) on migration and invasion of hepatocellular carcinoma (HCC) cells, and its possible mechanism associated with Dicer 1. Methods HepG 2 and HepG 2.2.15 cells were transfected with miR- 18 a inhibitor using Lipofectamine. Cell invasion was evaluated by transwell invasion assay, and cell migration was detected by transwell migration and wound-healing assays. Moreover, luciferase reporter assay was used to identify whether Dicer expression was regulated by miR- time RT-PCR and western blot were performed to analyze Dicer 1 expression. In addition, a functional restoration assay was performed to investigate whether miR-18 a promotes HCC cell migration and invasion by directly targeted Dicer 1. Results miR-18 a inhibitor can suppress the migration and invasion of HCC cells. Furthermore, suppression of Dicer l expression by small interfering RNA essentially abolished the inhibition of cell migration and invasion induced by miR-1 8 a inhibitor, restorating these activities to levels similar to the parental HCC cells. Interestingly, suppression of miR-18 a in HCC cells resulted in enhanced expression of Dicer 1. In addition, the results of a luciferase assay demonstrated targeted regulation of Dicer l by miR-18 a. Conclusion Our findings suggest that miR-18 a promotes migration and invasion of HCC cells by inhibiting Dicer l expression.