Interference of miR-107 with Atg12 is inhibited by HULC to promote metastasis of hepatocellular carcinoma.

Highly upregulated in liver cancer (HULC) had a significant predictive effect on tumor growth and metastasis of hepatocellular carcinoma (HCC); however, the mechanisms of HULC on HCC still need to be clarified. We attempted to determine the roles of HULC and miR-107 in autophagy and invasion of HCC. HULC siRNA reduced the level of autophagy. The impact of HULC siRNA on invasion can be reversed by activating autophagy in HCC cell lines. Further studies on HULC and autophagy were conducted. An interacting sequence between HULC and miR-107, as well as miR-107 and Atg12, was predicted by software. The relationship of each pair of molecules was confirmed by luciferase reporter assays. The negative impacts of miR-107 on autophagy and invasion were proved in HCC cell lines. The inhibitor of miR-107-promoted invasion can also be reversed by Atg12 siRNA. The changes of miR-107, Atg12, epithelial-mesenchymal transition, and autophagy in transplanted tumors of mouse models also confirmed the results in HCC cell lines. Finally, we find that HULC acts as an endogenous sponge, which abolishes the binding of miR-107 on the Atg12 3'-UTR and promotes autophagy and metastasis of HCC.