Abstract: Objective To determine whether miR- 424 affects cancer cell proliferation and autophagy through ATG14 in hepatocellular carcinoma (HCC) cells. Methods We detected miR-424-5p and ATG14 expression levels in surgical specimens of HCC and adjacent tissues and in different HCC cell lines (HepG2, SMMC-7721, Huh-7, MHCC97H, and HCCLM3) and normal human hepatocyte LO2 cells using qRT-PCR and Western blotting. In the cell transfection experiments, we observed the effects of miR-424-5p knockdown in Huh-7 cells and the effects of overexpression miR-424-5p and ATG14 in HCCLM3 cells on the proliferation, cell cycle, apoptosis and expression levels of autophagy-related proteins (LC3, Beclin1 and p62). Dual luciferase reporter assay was used to verify the possible interaction between miR-424-5p and ATG14. Results In HCC tissues and cells, ATG14 was highly expressed and miR- 424- 5p expression was downregulated. In HCC cells, overexpression of miR- 424-5p obviously suppressed cell proliferation and promoted cell apoptosis (P<0.05), while inhibiting miR-424-5p or overexpressing ATG14 significantly promoted cell proliferation and inhibited cell apoptosis (P<0.05). Dual luciferase reporter assay indicated that miR-424-5p inhibits HCC cells by targeting ATG14. In addition, inhibition of miR-424-5p and overexpression of ATG14 both enhanced the expressions of LC3-ΙΙ/LC3-Ι and Beclin1 and decreased p62 expression (P<0.05), but miR-424-5p overexpression reduced the expressions of LC3-ΙΙ/LC3-Ι and Beclin1 and increased p62 expression (P<0.05). Conclusion MiR-424 inhibits HCC cell autophagy and proliferation through regulating ATG14.

Key words: hepatocellular carcinoma; miR-424-5p; ATG14; autophagy; proliferation; apoptosis