MiR-124 inhibits the migration and invasion of human hepatocellular carcinoma cells by suppressing integrin αV expression

Tumor metastasis is the major cause of cancer-related death especially in human hepatocellular carcinoma (HCC). Although microRNAs have been implicated in tumor development, the roles of miR-124 in HCC metastasis are still not well understood. We conducted functional analysis in this study to investigate miR-124. We observed that miR-124 significantly retarded the wound healing and migration of HCC SMMC-7721 and BEL-7404 cells. Further analysis indicated miR-124 directly targeting the transcriptional factor Sp1 which is an important transcription factor for the integrin alpha V subunit gene transcription. Co-transfection of miR-124 with the luciferase reporter containing Sp1 3' untranslated region (UTR) significantly suppressed the luciferase activities. While mutation of the binding site of miR-124 in Sp1 mRNA 3' UTR completely abrogated the suppression of miR-124. Overexpression of miR-124 resulted in robust downregulation of Sp1 and integrin aV expression at either mRNA or protein level. Ectopic expression of miR-124 in HCC dramatically repressed the wound healing and migration in vitro and tumor metastasis in mouse experiments. Our findings demonstrated that miR-124 played as an important role in regulation of integrin aV expression in HCC, and reintroduction of miR-124 might be an alternative therapeutic strategy for controlling integrin aV expression in HCC.