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.

Based on thermodynamic principle, the critical relative humidity of electrolytes is closely related to their solubility. The authors explored the relationship theoretically and calculated critical relative humidity of 21 electrolytes from their solubility in the light of Raoult's law and extended Wilson model. The results indicate that the critical relative humidity values calculated by Raoult's law can not accord with the reported ones and there is a systematic error in the high concentration range; while these calculated by extended Wilson model are comparable to the reported ones.