MicroRNA-133a inhibits cell proliferation, colony formation ability, migration and invasion by targeting matrix metallopeptidase 9 in hepatocellular carcinoma.

MicroRNA‑133a (miR‑133a) is downregulated in various types of human malignancy, including hepatocellular carcinoma (HCC), renal cell carcinoma, esophageal squamous cell carcinoma, bladder cancer, ileal carcinoid and rhabdomyosarcoma. The aim of the present study was to examine the effects of miR‑133a on HCC cell proliferation, colony formation, migration and invasion. miR‑133a was transfected into the HCC HepG2 and SMMC‑7721 cell lines and the expression levels of miR‑133a were determined; in addition, cell viability assays, colony formation assays, cell migration assays, cell invasion assays, western blot analyses and luciferase assays were performed in the HCC cell lines. The results demonstrated that miR‑133a significantly inhibited cell proliferation, colony formation, migration and invasion in HepG2 and SMMC‑7721 cells. To the best of our knowledge, the present study also provided the first evidence that miR‑133a directly downregulated the expression of matrix metallopeptidase 9 (MMP‑9) in the HCC cells. In conclusion, the results of the present study indicated that miR‑133a may have suppressed cell proliferation, colony formation, migration and invasion via the downregulation of MMP‑9 in HCC cell lines. Therefore, MMP‑9 may be used for the development of novel molecular markers and therapeutic approaches to inhibit hepatocellular carcinoma metastasis.