MiR-670-5p induces cell proliferation in hepatocellular carcinoma by targeting PROX1

MiRNAs, as oncogenes or as anti-oncogenes, play critically regulated roles in human cancers at posttranscriptional level. A number of dysregulated miRNAs has been observed in HCC. However, the expression and function of miR-670-5p have not been evaluated in HCC to date. In this study, we examined and confirmed the over-expression of miR-670-5p in HCC and in hepatoma-derived cells Hep3B. At least 60% of HCC tissues showed a greater than three-fold enhance in the expression of miR-670-5p compared with paired adjacent non-cancerous tissues. Knockdown studies for miR-670-5p showed that the expression of miR-670-5p promoted cellular proliferation. In tissues and cells with high expression of miR-670-5p, decreased expression of PROX1, a miR-670-5p predicated target, was detected. It confirmed that PROX1 expression was obviously affected by the expression of miR-670-5p. Furthermore, overexpression of PROX1 greatly inhibitted cellular proliferation. Therefore, it was inferred that miR-670-5p may play important roles in enhancing proliferation activity that is associated with HCC by modulating PROX1 expression at posttranscriptional level.