Hsa_circ_0091581 could act as a sponge of miR-526b in HCC cells. (a) Predicted miR-526b binding site and corresponding mutant sites in the hsa_circ_0091581 sequence (wt, wild-type; mut, mutant). (b) Relative luciferase activity in SMMC-7721 cells co-transfected with wt or mut luciferase reporters and miR-526b mimics or corresponding negative control. (c) Relative miR-526b expression in SMMC-7721 cells transfected with hsa_circ_0091581 siRNA. (d) Relative miR-526b expression in 46 pairs of HCC tissues and ANTs was detected using qRT-PCR. (e) Correlation between relative hsa_circ_0091581 expression and relative miR-526b expression analyzed with Spearman’s analysis. (g, f) CCK8 and colony formation proliferation assays of SMMC-7721 cells co-transfected with hsa_circ_0091581 siRNA and miR-526b inhibitor or corresponding negative controls. Results are presented as mean ± SD. *P < 0.05, **P < 0.01, ***P < 0.001.