CircRNA has_circ_0078710 acts as the sponge of microRNA-31 involved in hepatocellular carcinoma progression

Circular RNAs (circRNAs) as new types of endogenous non-coding RNAs have been recently identified important roles in certain types of pathological responses, and in the occurrence and progression of a variety of human malignancies. In the present study, we aimed to evaluate the role of has_circ_0078710, which is back spliced by THBS2 gene in hepatocellular carcinoma (HCC). Expression levels of has_circ_0078710 were tested in both HCC tissue samples and cells using real-time qRT-PCR. Hascirc_0078710 was significantly unregulated in HCC tissues and cells. Moreover, HCC patients with high level of has_circ_0078710 had the advance stage (TNM III-IV). Finally, we constructed an interaction network among circRNA-miRNA-mRNA and we identified miR-31 as the has_circ_0078710-associatedmiRNA. Furthermore, overexpression of has in HCC could up-regulate HDAC and CDK2 levels by sponging miR-31, simultaneously mediating the expression of cell cycle components (cyclin A, cyclin D1, CDK4) and negative cell cycle regulator p21. In vitro and in vivo functional studies showed that overexpression of has in HepG2, SMMC-7721 cell lines significantly promoted cell proliferation, migration, invasion and tumor growth by inducing the cell cycle progression. In summary, we identified Hassirc_0078710 as a potential HCC biomarker.