ABSTRACT
Objective To study the effects of cleavage of Bcl-2 by two DNAzymes on apoptosis of human hepatoma cell line (HepZ1).Methods Two “10-23” DNAzymes(DzT and DzTi) targeting Bcl-2 mRNA and their analogues(DzT' and DzTi') were synthesized and used to cleave Bcl-2 mRNA in vitro and in BEL-7402 cells.The RT-PCR was performed to assess the cleaving efficiency.Expression of Bcl-2 protein was determined by immunofluorescent method.Cell apoptosis was detected by flow cytometry.Results The unmodified Enzymes DzT,and its modified form DzTi,which had an added 3'-inverted thymidine,could effectively cleave Bcl-2 mRNA in vitro.After transfected into BEL-7402 cells,DzTi exhibited more powerful cleaving ability than DzT,significantly down-regulated the level of Bcl-2 protein(P ＜0.01) and inhibited the cell growth(P ＜0.05).The results of flow cytometry suggested that the apoptosis rate of DzT and DzTi significantly increased,appeared apoptotic peak.Cell cycle was delayed in DzT and DzTi group,proportion of cells in G0/G1 increased,S phase cells decreased.Conclusion The synthesized DNAzymes could effectively cleave Bcl-2 mRNA,decrease the level of Bcl-2 protein and induce hepatoma cells apoptosis.