miR-206 inhibits cell proliferation, invasion, and migration by down-regulating PTP1B in hepatocellular carcinoma

Protein tyrosine phosphatase 1B (PTP1B) has been reported as an oncogene in hepatocellular carcinoma (HCC). However, how PTP1B is regulated in HCC remains unclear. MicroRNAs (miRNAs) are a class of small non-coding RNAs involved many biological processes including tumorigenesis. In this study, we investigated whether miRNA participated in the regulation of PTP1B in HCC. We found that miR-206, which was down-regulated during tumorigenesis, inhibited HCC cell proliferation and invasion. Overexpression of miR-206 inhibited proliferation, invasion, and migration of HCC cell lines HepG2 and Huh7. Mechanistically, we demonstrated that miR-206 directly targeted PTP1B by binding to the 3'-UTR of PTP1B mRNA as demonstrated by the luciferase reporter assay. Overexpression miR-206 inhibited PTP1B expression while miR-206 inhibition enhanced PTP1B expression in HepG2 and Huh7 cells. Functionally, the regulatory effect on cell proliferation/migration/invasion of miR-206 was reversed by PTP1B overexpression. Furthermore, tumor inoculation nude mice model was used to explore the function of miR-206 in vivo. Our results showed that overexpression of miR-206 drastically inhibited tumor development. In summary, our data suggest that miR-206 inhibits HCC development by targeting PTP1B.