Targeting of pertechnetate imaging of HepG2 hepatocellular carcinoma through the transduction of the survivin promoter controls the sodium iodide symporter

Currently, the intratumoral (i.t.) injection of adenovirus-mediated cancer gene therapy has been reported in numerous investigations. However, the intravenous (i.v.) injection of adenovirus is more suited for disseminated tumors and distant metastatic lesions. The survivin promoter, which has tumor-selective capability, was used to construct an adenoviral vector, and its feasibility to carry the sodium iodide symporter (NIS) gene for potential tumor-targeting transfection into carcinoma was evaluated in this study. An in vitro cellular assay using HepG2 hepatocellular carcinoma (HCC) cells exhibited iodide uptake after infection with Ad-Sur-NIS, and the uptake reached a maximum level at 30 min. The effective half-life of 125I efflux from Ad-Sur-NIS infected HepG2 cells was 16.67 ± 1.08 min. Moreover, in vivo transfection of Ad-Sur-NIS via i.v. injection induced more effective transfection and, accordingly, induced higher uptake of pertechnetate in HCC xenograft tumors than did the non-specific transfection of Ad-CMV-NIS (i.v.) (P<0.05), indicating possible selective NIS gene-transfecting image strategies by the survivin promoter.