Abstract: Objective To investigate the expression of Hsa-miR-4282 in hepatocellular carcinoma cell line SMMC-7721 and its effect on cell growth. Methods The expression of Hsa-miR-4282 in human normal liver epithelial cell line HL-7702，human hepatoma cell lines MHCC97-H and SMMC-7721，20 cases of primary liver cancer tissues and their corresponding adjacent tissues were detected by quantitative real-time PCR. The SMMC-7721 cells were transfected with Hsa-miR-4282 mimics（up-regulation group） or Hsa-miR-4282 inhibitor（down-regulation group） by transient transfection method，and negative control group were set in the up-regulated group and the down-regulated group，respectively.After transfection，the cell proliferation ability was detected by MTT assay，the cell clone formation ability was detected by plate cloning assay，and the apoptosis ability was detected by flow cytometry. Results The expres-sion of Hsa-miR-4282 in liver cancer tissues，liver cancer cells MHCC97-H and liver cancer cells SMMC-7721 were lower than that in adjacent tissues and normal liver cells HL-7702 （P<0.05）.The MTT assay showed that the OD value of liver cancer SMMC-7721 cells up-regulated by Hsa-miR-4282 was lower than that of the negative control group，but the OD value of liver cancer SMMC-7721 cells down-regulated by Hsa-miR-4282 was higher than that of the control group.Plate cloning experiments showed that the number of cell clones in the down-regulated group was higher than that in the negative control group ［（240±7） vs （191±10），P=0.005）］，while the number of cell clones in the up-regulated group was lower than that in the control group ［（146±10） vs （193±12），P=0.013）］.The results of flow cytometry showed that the apoptosis rate of Hsa-miR-4282 up-regulated group was higher than that of the control group ［（23.89±1.89）% vs （16.6±1.14）%，P=0.009）］，while the rate in Hsa-miR-4282 down-regulated group was lower than that of the control group ［（14.98±0.46）% vs （17.79±0.73）%，P=0.010］. Conclusions  Up-regulation of Hsa-miR-4282 can inhibit the proliferation of liver cancer SMMC-7721 cells and promote cell apoptosis，which may be related to the pathogenesis of liver cancer.

Key words: Primary liver cancer, Hsa-miR-4282, Liver cancer cell Line SMMC-7721, Proliferation, Apoptosis