Fig. 5: In vitro and in vivo functional analysis of miR-126/PLK-4 axis in HCC.

a, b Western blotting analysis of PLK-4 expression in HCC cells after transfected with PLK-4 plasmid or PLK-4 siRNA. c Knockdown of PLK-4 dramatically inhibited the cell colony formation ability. d Overexpression of PLK-4 promoted cell growth in Hep-3B cells as evaluated by EDU assay. Scale bars, 50 μm. e, f The expression levels of PLK-4 after transfected with PLK-4 siRNA, miR-126 mimic, and miR-126 mimic&PLK-4. g, h PLK-4 knockdown suppressed cell proliferation, while overexpression of PLK-4 abolished the suppressive effect of miR-126 on cell proliferation rate in liver cancer cells, as determined by the MTT assays. i Decreased PLK-4 inhibited cell invasion, while overexpression of PLK-4 abolished the suppressive effect of miR-126 on cell invasion ability in HCC cells. Scale bars, 50 μm. j The rate of cell apoptosis was much higher after transfection with PLK-4 siRNA or miR-126 mimics, but was attenued in the group of co-transfected with miR-126 mimics and PLK-4 plasmid. k, l The in vivo effect of PLK-4 was evaluated in xenograft mouse models bearing tumors originating from SMMC-7721 cells; n = 6 per group. Mean ± SD, *P < 0.05, **P < 0.01, unpaired Student’s t test or one-way ANNOVA followed by multiple t test