In vivo sodium iodide symporter gene therapy of prostate cancer

Radioiodine therapy, the most effective form of systemic radiotherapy avail able, is currently useful only for thyroid cancer because of thyroid-specif ic expression of the sodium iodide symporter (NIS). Here we explore the eff icacy of a novel form of gene therapy using adenovirus-mediated in vivo NIS gene transfer followed by I-131 administration for treatment of prostate c ancer. Prostate cancer xenografts in nude mice injected with an adenovirus carrying the NIS gene linked to the cytomegalovirus (CMV) promoter revealed highly active uptake of radioiodine. Following administration of 3 mCi of I-131, we observed an average tumor volume reduction of 84 +/- 12%. These r esults show for the first time that in vivo NIS gene delivery into non-thyr oidal tumors is capable of inducing accumulation of therapeutically effecti ve radioiodine doses and might therefore represent an effective and potenti ally curative therapy for prostate cancer.