Human sodium/iodide symporter gene induced iodine uptake in human lung adenocarcinoma via baculovirus

To investigate human sodium/iodide symporter (hNIS) induced iodine uptake in human lung adenocarcinoma via baculovirus, a recombinant baculovirus encoding hNIS gene was constructed under the control of CMV promoter (Bac-CMV-hNIS). In vitro, baculovirus infected A549 cells accumulated about 27 times more I-125 than that of noninfected cells. The I-125 uptake was maximal after 30-min incubation of the cells, and efflux of the radioactivity was rapid, with 50% lost during the first 2 min after I-125-containing medium had been replaced by nonradioactive medium. Competition experiments in the presence of sodium perchlorate revealed a dose-dependent decrease of I-125 uptake. Bac-CMV-hNIS infected tumor cells were selectively killed by exposure to I-131, as revealed by clonogenic assays. In nude mice, Bac-CMV-IINIS infected A549 cells accumulated more I-131 than that of the control monitored by 1-h scintigraphy after I-131 administration. The transduction of hNIS gene through baculovirus is sufficient to induce iodine transporting in A549 cells in vitro and in vivo, outlining the potential of this novel tumor gene imaging approach. But a rapid efflux of radioactivity from the tumor was shown in vivo and the in vivo therapy test showed no sign of effect.