MiR‐490‐3p inhibits autophagy via targeting ATG7 in hepatocellular carcinoma

The miR‐490‐3p was transfected into HepG2 cells to explore the correlation between miR‐490‐3p and hepatocellular carcinoma cell proliferation, apoptosis, and autophagy and its downstream target gene ATG7. Then we could possibly provide a mechanism for the treatment of hepatocellular carcinoma. MiR‐490‐3p was screened out by fold change > 4 and P < 0.01 using gene microarray data. The expression level of miR‐490‐3p was tested by qRT‐PCR and the prognosis analysis was achieved by using TCGA data. The cell proliferation was tested via colony formation assay and CCK‐8 after the miR‐490‐3p mimics were transfected into HepG2 cells; the variations of cell cycle and apoptosis was examined by flow cytometry assay; the number of autophagosome was observed by electron microscopy and the changes of autophagy‐relative protein LC‐II and LC‐I as well as their ratio was tested by western blot. MiR‐490‐3p is low expressed in hepatocellular carcinoma cell lines and tissues. The results of TCGA showed that miR‐490‐3p high expression indicated better prognosis. After HepG2 cells were transfected with miR‐490‐3p mimics, cell viability was increased, cell proliferation was enhanced, cell cycle was blocked in G0/G1 phase, cell apoptosis rate was increased, the number of autophagosomes was reduced, autophagy‐associated protein LC‐II was decreased, and LC‐I was increased and their ratio was decreased. After 3‐MA was added, cell proliferation was declined, cell apoptosis rate was increased. Besides, the autophagy was inhibited by knocking down the ATG7, which promoted the cell apoptosis. MiR‐490‐3p could suppress cell proliferation, retard cell cycle and upgrade cell apoptosis by inhibiting autophagy in HCC cells via targeting ATG7. © 2018 IUBMB Life, 70(6):468–478, 2018