Objective:To construct eukaryotic expression plasmid pEGFP-N1-WWOX and transiently express it in SMMC-7721 cells.Methods:Total mRNA was extracted from normal human liver tissue.RT-PCR was used to amplify the aimed segments WWOX cDNA which was then digested with HindIII and BamHI and inserted into a eukaryotic expression plasmid pEGFP-N1 to construct pEGFP-N1-WWOX.The constructed plasmid was transfected into SMMC-7721 cells by lipofectamine 2000-mediated transfer method.The expression of WWOX in transfected SMMC-7721 cells was detected 24,36 and 48 h post-transfection with fluorescence microscope and the expression level of WWOX mRNA in transfected SMMC-7721 cells was assay by using RT-PCR.The change of WWOX expression and cell proliferation rates were detected by immunocyto-chemistry and MTT methods respectively.Results:The results showed pEGFP-N1-WWOX was successfully constructed and expressed transiently in SMMC-7721 cells.At 48th hour post-transfection,the number of positive cells was increased significantly and much brighter green fluorescence could be detected,while no green fluorescence was detected in the control group.In SMMC-7721 cells transfected with pEGFP-N1-WWOX a high level of porcine WWOX was detected.WWOX ex-pressed by transfected cells could significantly inhibit the proliferation of SMMC-7721 cells.Conclusion:pEGFP-N1-WWOX was expressed successfully in SMMC-7721 cells,which suggested that might be used as a new therapeutic method for liver cancer. Objective: To construct eukaryotic expression plasmid pEGFP-N1-WWOX and transiently express it in SMMC-7721 cells. Methods: Total mRNA was extracted from normal human liver tissue. RT-PCR was used to amplify the aimed segments WWOX cDNA which was then digested with HindIII and BamHI and inserted into an eukaryotic expression plasmid pEGFP-N1 to construct pEGFP-N1-WWOX. The constructed plasmid was transfected into SMMC-7721 cells by lipofectamine 2000-mediated transfer method. The expression of WWOX in transfected SMMC-7721 cells was detected 24, 36 and 48 h post-transfection with fluorescence microscope and the expression level of WWOX mRNA in transfected SMMC-7721 cells was assayed by using RT-PCR. The change of WWOX expression and cell proliferation rates were detected by immunocyto-chemistry and MTT methods respectively. Results: The results showed pEGFP-N1-WWOX was successfully constructed and expressed transiently in SMMC-7721 cells. At 48th hour post-transfection, the number of positive cells w as compared with pEGFP-N1-WWOX a high level of porcine WWOX was detected. WWOX ex-pressed by transfected cells could significantly inhibit the proliferation of SMMC-7721 cells. Conflusion: pEGFP-N1-WWOX was expressed successfully in SMMC-7721 cells, which suggested that might be used as a new therapeutic method for liver cancer.