Potent antitumor activity of double-regulated oncolytic adenovirus-mediated ST13 for colorectal cancer.

Following targeted gene virotherapy, the suppression of tumorigenicity 13 (ST13) gene was inserted into the double-regulated oncolytic adenovirus SG500 to ensure more safety and potent antitumor activity against colorectal cancer in vitro and in vivo. We generated the ST13-expressing oncolytic adenovirus SG500-ST13, with which colorectal carcinoma cell lines SW620 and HCT116, and the lung fibroblast cell line WI38, were infected. Crystal violet staining was carried out to detect the cytopathic effect in cells, and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method was used to assay cell viability. The effect of apoptosis induced by SG500-ST13 was confirmed by Hoechst staining and the TdT-mediated dUTP-biotin nick-end labeling method. To further identify the antitumor effects of SG500-ST13 on HCT116 xenografts in Balb/c nude mice, the induction of cell death was assessed by hematoxylin-eosin staining. Immunohistochemical study was also carried out.