Expression and activity of human Na+/I- symporter in human glioma cells by adenovirus-mediated gene delivery

Radioiodide concentrating activity in the thyroid, mediated by human Na+/I- symporter (hNIS), provides a mechanism for effective radioiodide treatment for patients who have invasive, recurrent, and metastatic thyroid cancers after total thyroidectomy. In an attempt to develop hNIS gene transfer for radioiodide therapy for patients with brain tumors, we have constructed recombinant adenoviruses, rAd-CMV-hNIS#9 and rAd-CMV-FLhNIS, to express exogenous hNIS in U1240 and U1240Tag human glioma cells. U1240Tag differs from U1240 glioma cells in that it expresses the SV40 large T antigen oncoprotein. In both U1240 and U1240Tag cells, radioiodide uptake (RAIU) activity in the cells infected with rAd-CMV-hNIS#9 or rAd-CMV-FLhNIS increases as the adenoviral MOI increases. The protein expression profile of hNIS in infected cells is generally in agreement with their RAIU activity profile. Although the expressed hNIS#9 protein appeared to have a shorter half-life than FLhNIS, hNIS#9 expression could be maintained by multiple infections in these cells. In addition, we show that hNIS can be expressed and function in a xenografted human glioma by intratumoral injection of rAd-CMV-hNIS#9.