RESUMO
This study sought to probe the feasibility of instituting a radioiodide treatment for androgen-independent prostate cancer by adenovirus transfer of the hNIS gene. A recombinant adenovirus, Ad-CMV-NIS, that expressed the NIS gene under the control of cytomegalovirus (CMV) promoter was constructed. In vitro, after infection with Ad-CMV-NIS,PC-3 prostate cancer cells exhibited an uptake of perchlorate-sensitive iodide, approximately 120 times higher than that exhibited by negative control Ad-CMV-GFP-infected cells. The half-time of efflux was 26.6 min. Clonogenic assays demonstrated that Ad-CMV-NIS-infected cancer cells were selectively killed by exposure to 131I. In vivo, Ad-CMV-NIS infected tumors showed significant radioiodine accumulation (16.30 +/- 8.72)% ID/g at 2h postinjection) with an effective half-life of 5.4h. The tumor could be clearly visualized by 131I scintigraphy. These data indicate that infection with Ad-CMV-NIS is an efficient way to induce radioiodide uptake in vitro and in vivo, thus suggesting that NIS-based gene therapy has the potential for use in androgen-independent prostate cancer.