Objective To investigate the expression of circular RNA ( cirRNA ) hsa_ circ_0091579 in human hepatocellular carcinoma ( HCC) cell lines and its effect on the proliferation, migration, and invasion of HCC cells. Methods Human HCC cell lines SMMC - 7721, Huh - 7, MHCC - 97H, and HepG2 and normal human liver cell line HL - 7702 were cultured in vitro. RNA was extracted from cells and quantitative real - time PCR ( qRT - PCR) was used to measure the expression of hsa_circ_0091579 in HCC cell lines and normal human liver cell line. Small interfering RNA ( siRNA) was designed for the cyclic splicing site of hsa_circ_0091579, and HepG2 and Huh - 7 cells were transfected with hsa_circ_0091579 siRNA in vitro ; qRT - PCR was used to verify transfection efficiency. The experiment was divided into siRNA group ( transfected with hsa_circ_0091579 siRNA) and NC group ( transfected with negative control siRNA), and CCK - 8 assay, flow cytometry, wound healing assay, and Transwell assay were used to investigate the effect of hsa_circ_0091579 on cell proliferation, apoptosis, migration, and invasion in HepG2 and Huh - 7 cells. Dual luciferase reporter gene assay was used to verify the predicted target. The t - test was used for comparison of continuous data between the two groups. Results Compared with the normal human liver cell line HL - 7702, the HCC cell lines SMMC - 7721, Huh - 7, MHCC - 97H, and HepG2 had a significant increase in the expression level of hsa_circ_0091579 (t = 14 . 27, 36. 34, 26 . 70, and 36.16, all P < 0. 001). Compared with the NC group, hsa_circ_0091579 siRNA effectively silenced hsa_circ_0091579 in HepG2 and Huh - 7 cells ( t = 14. 22 and 27. 20, P = 0. 005 and 0. 001 ) . CCK - 8 assay and flow cytometry showed that compared with the NC group, the siRNA group had a significant reduction in the proliferative activity of HepG2 and Huh - 7 cells and a significant increase in apoptosis rate (all P < 0. 05 ) ; wound healing assay and Transwell assay showed that compared with the NC group, the siRNA group had significant reductions in the migration and invasion abilities of HepG2 and Huh -7 cells (t = 19. 63, 13. 61, 20. 75, and 18. 45, P = 0. 003, 0. 005, 0. 002, and 0. 003). Luciferase reporter assay showed that compared with the NC group, miR - 149, miR - 490 - 5p, and miR - 502 - 5 p significantly reduced the activity of wild - type luciferase plasmids ( t = 10. 01, 9. 13, and 61. 49, P = 0. 010, P = 0. 012, and P <0. 001). Conclusion Hsa_circ_0091579 is highly expressed in HCC cell lines and may play the role of oncogene by inhibiting miR - 149, miR - 490 - 5p, and miR - 502 - 5p. [ABSTRACT FROM AUTHOR]