Abstract: Objective To investigate the clinical implications of abnormal expression of miR-607 in hepatocellular carcinoma (HCC) and its influence on HCC cell proliferation and migration. Methods The expression of miR-607 in 45 pairs of HCC and adjacent tissues were detected with real- time PCR, and the correlation between miR-607 expression and clinicopathological features of the patients was analyzed. The effects of transfection with miR-607 mimics on proliferation, apoptosis, migration and invasion of two HCC cell lines (Huh-7 and HCCLM3) were evaluated using CCK-8 assay, flow cytometry, wound-healing assay and Transwell assay. A dual-luciferase reporter system was used to detect the direct binding between miR-607 and 3'-UTR of TRPC5 mRNA. Western blotting was used to measure the expressions of TRPC5, CCND1, MMP2 and phosphorylated Akt in the HCC cells. Results The expression of miR-607 was significantly decreased in HCC tissues (P=0.029) and HCC cell lines (P<0.05). In HCC patients, a low expression of miR-607 was associated with a larger tumor size (>5 cm, P=0.031), vascular invasion (P=0.027) and advanced TNM stages (III + IV, P=0.015). In the two HCC cell line, overexpression of miR-607 significantly inhibited cell proliferation, migration, and invasion and enhanced cell apoptosis (P<0.05). The results of dual-luciferase reporter assay confirmed that TRPC5 was a direct target of miR- 607 in HCC cells. Overexpression of miR-607 significantly inhibited the expressions of TRPC5, CCND1, and MMP2 and suppressed Akt phosphorylation in HCC cells (P<0.05). Conclusion A low expression of miR-607 in HCC is associated with poor clinicopathological phenotypes of HCC. Overexpression of miR-607 inhibits HCC growth and metastasis possibly by down- regulating TRPC5, which causes Akt signaling inactivation.

Key words: miR-607; hepatocellular carcinoma; TRPC5; Akt signal pathway; metastasis