Abstract: Objective To study the effects of oncolytic adenoviruses ZD55 harboring IL-24 gene （ZD55-IL-24） on the apoptosis of human melanoma cell line A375. Methods The oncolytic adenoviruses ZD55-IL-24 were verified by PCR. Then, the viruses were propagated, purified, and titrated by HEK293 cell plaque assay. A375 cells were cultured, divided into three groups transfected with ZD55-IL-24, ZD55 fused with enhanced green fluorescent protein （ZD55-EGFP）, and replication-deficient adenovirus ZD55 carrying IL-24 gene （AD-IL-24）， respectively. The multiplicity of infection was 0.1, 1, 10 and 100, respectively. Subsequently, the cytotoxity of these viruses and proliferation of A375 cells were determined by crystal violet staining and methyl thiazolyl tetrazolium （MTT） assay, respectively. The expressions of E1A and IL-24 protein were detected by Western blot in A375 cells. Results PCR verified that the adenoviruses ZD55-IL-24 contained IL-24 gene without wild adenovirus contamination. Crystal violet staining revealed that ZD55-IL-24 had an obvious cytotoxic effect on A375 cells, and MTT assay indicated that ZD55-IL-24 inhibited the proliferation of A375 cells in a time- and concentration-dependent manner. As shown by Western blot analysis, ZD55-IL-24 expressed IL-24 and E1A protein in A375 cells with a high efficiency. Conclusions The oncolytic adenoviruses ZD55-IL-24 can efficiently express IL-24 gene, inhibit the proliferation of, and induce the apoptosis in A375 cells.

Key words: Genes,IL-24