ABSTRACT
Objective To investigate the effects of down-regulating Cyclin D1 expression on Mdm2 gene expression and proliferation of human hepatoma cells.Methods Cyclin D1-siRNA was transfected into the hu man hepatoma cell line Hep3B s with liposome.The experiment was divided into the blank control group,negative control siRNA (NC-siRNA) group and Cyclin D1-siRNA group.RT-PCR and Western blot were used to detect the expressions of Cyclin D1,Mdm2,Mdm4,P53 and P21.The cell cycle was measured by flow cytometer;the cellular activity was tested with MTT;the cell apoptosis was examined by TUNEL.Results Compared with the blank control group and NC-siRNA group,the expressions of P53 and P21 in the Cyclin D1-siRNA group were increased (P＜0.05),while the expressions of Cyclin D1,Mdm2 and Mdm4 were decreased (P＜0.01);there were no significant differences in the G1,S and G2 phases among 3 groups(P＞0.05);the cell vitality in the in the Cyclin D1-siRNA group was significantly weakened compared with the other two groups(P＜0.01),while the cell apoptosis was significantly enhanced(P＜0.01).Conclusion The down-regulation of Cyclin D1 gene expression could inhibit the expressions of Mdm2 and Mdm4,and up-regulates the expressions of P53 and P21.Down-regulating Cyclin D1 expression can inhibit the proliferation of liver cancer cells and promotes their apoptosis.