miR-203 suppresses the proliferation and metastasis of hepatocellular carcinoma by targeting oncogene ADAM9 and oncogenic long non-coding RNA HULC.

MicroRNAs (miRNAs) have been integrated into tumorigenic programs by regulating genes at post-transcriptional level. Long non-coding RNAs (lncRNAs) are novel targets for miRNAs. Here, we reported that miR-203 down-regulation was closely linked to advanced clinical features and poor overall survival (OS) of patients with hepatocellular carcinoma. We also confirmed that miR-203 and oncogene ADAM9 (a disintegrin and metalloproteinase 9)/oncogenic long non-coding RNA HULC (highly up-regulated in liver cancer) were inversely expressed in hepatocellular carcinoma (HCC) tissues or cell lines. More intriguingly, up-regulation of miR-203 diminished the expression of ADAM9 and HULC in HCC cancer cells. Over-expression of miR-203 could markedly inhibit cell proliferation, invasion and induce cell apoptosis. Furthermore, we identified that miR-203 modulated ADAM9 and HULC in a novel post-transcriptional regulatory mechanism. Over-expression of HULC partly rescued the miR-203-mediated antitumor effects. These results suggested that miR-203 played tumor suppressive roles by downregulating ADAM9 and HULC and indicated its potential application in cancer treatment.