Antitumor effect of the combined use of oncolytic adenovirus carrying interleukin-24 gene with docetaxel on prostate cancer DU145 cells

Abstract

Objective To investigate the anti-tumor effect of combining oncolytic adenovirus expressing human interleukin-24 gene (ZD55-IL-24) with docetaxel (DTX) on human prostate cancer DU145 cells. Methods The experiment was divided into 4 groups, ZD55-IL-24 (MOI=1.0) (multiplicity of infection, MOI)+ DTX (0.5 ng/ml) group, ZD55-IL-24 (MOI=5.0 ) group, DTX (1.0 ng/ml) group and phosphate buffer saline (PBS) control group. The viability of DU145 cells treated with DTX (0, 0.5, 1.0, 1.5, 2.0 ng/ml) alone and ZD55-IL-24 (0, 1.0, 5.0, 10.0, 20.0 MOI) alone 96 hours was assessed by methyl thiazol tetrazolium (MTT) assay. And the viability of DU145 cells of 4 groups with 96 hours treatment was assessed by MTT assay. The inhibination of cell proliferation of 4 groups DU145 cells was evaluated by crystal violet dye method. The migration ability of 4 groups DU145 was detected by Transwell migration assay. The cell apoptosis was determined by Hoechst-33342 staining. The expression of E1A, IL-24, proteins of cysteinyl aspartate-specific protease (Caspase) signal pathway and nuclear factor-κB (NF-κB) signal pathway were detected by Western blotting analysis. Results After treated 96 hours, the cell viability rate of DU145 cell of ZD55-IL-24 (MOI=1.0) + DTX (0.5 ng/ml) group (38.20±5.86)% was lower than ZD55-IL-24 (MOI=5.0) group (78.90±5.27)% (t=1.957, P=0.043) and DTX (1.0 ng/ml) group (56.30±7.86)% (t=2.090, P=0.035). The crystal violet dye method showed that the ZD55-IL-24 (MOI=1.0)+ DTX (0.5 ng/ml) group had better cytotoxic effects than ZD55-IL-24 (MOI=5.0) group and DTX (1.0 ng/ml) group. Hoechst-33342 staining showed that the percentage of apoptotic cells of ZD55-IL-24 (MOI=1.0)+ DTX (0.5 ng/ml) group (38.50±6.86)% was significantly higher than that in ZD55-IL-24 (MOI=5.0) group (22.40±2.30)% (t=2.633, P=0.029) and DTX (1.0 ng/ml) group (16.70±5.67)% (t=3.166, P=0.017) after 48 hours. Transwell migration assay showed that the number of migrating cells of ZD55-IL-24 (MOI=1.0)+ DTX (0.5 ng/ml) group (21.3±2.7) cells was less than that of ZD55-IL-24 (MOI=5.0) group (30.3±3.1) cells (t=2.404, P=0.037) and DTX (1.0 ng/ml) group (165.7±14.3) cells (t=3.540, P=0.012) after 48 hours’ treatment. Western blotting assay showed that ZD55-IL-24 (MOI=1.0)+ DTX (0.5 ng/ml) group expressed IL-24 and E1A. The replication of adenovirus ZD55-IL-24 in DU145 cells was not affected by DTX (1.0 ng/ml) obviously. The anti-tumor effect in DU145 cells of ZD55-IL-24 (MOI=1.0)+ DTX (0.5 ng/ml) group was related with expression of proteins in Caspase signal pathway and NF-κB signal pathway. Conclusion The combination of ZD55-IL-24 and DTX have better anti-tumor effect in DU145 cells and offer a novel approach for therapy of prostate cancer. Key words: Oncolytic adenovirus; Docetaxel; Prostate cancer