Therapeutic effect of triple regulated adenovirus vector expressing mda7/IL24 on liver cancer in vitro / 肿瘤

ABSTRACT

Objective: To construct an E1 A-deleted 24-bp triple regulated replicative adenovirus vector SG600/interleukin24 (IL24), which was driven by both hTERT promoter and HRE promoter. The level of IL24 in liver cancer cells was determined and the replication capacity of SG600/ IL24 and its killing effects on liver cancer cells were observed. Methods: SG600-IL24 vector was constructed using DNA cloning and recombination techniques. The IL24 gene expression in liver cancer cell lines SMMC-7721 and BEL-7404 and normal cell line BJ was detected by ELISA assay. The replications of SG600/IL-24 in different cell lines were determined by evaluating TCID50 (50% tissue culture infectious dose) at 49 and 96 h. In vitro cell-killing effects of SG600/IL24 on the three liver cancer cell lines were analyzed by MTT assay and CPE (cytopathic effect) staining method at different MOI values. Results: IL24 was over-expressed in both SMMC-7721 and BEL-7404 cells but was weakly expressed in BJ cells. At 48 and 96 h post infection the replication of SG600/IL-24 were 794 and 7940 folds in SMMC-7721 cells; 622 and 7 810 folds in BEL-7404 cells; 20 and 200 folds in BJ cells. MTT assay showed that the MOI values of SG600/IL24 for killing 50% and 90% cells were 0.3 and 5 for SMMC-7721 cells; 3 and 20 for BEL-7404 cells; 50 and 150 for BJ cells. CPE staining demonstrated that SG600/IL24 had significant killing effects on both liver cancer cells SMMC-7721 and BEL-7404 but had no significant influence on BJ cells. The cell-killing capability of SG600/IL24 was superior than that of replicative adenovirus ZD55/IL24 and non replicative adenovirus Ad-IL24. Conclusion: After SMMC-7721 and BEL-7404 liver cancer cells are infected with SG600/1124 at high efficiency, the virus replication is active and the expression of IL24 increases greatly. SG600/IL24 has specific cell-killing effects on the two liver cancer cell lines but has no significant influence on normal cells. This study provides a basis for further investigating the effect of SG600/IL24 on liver cancer in vivo.