The in Vivo Study on Transfer of Human Sodium/Iodide Smporter Gene Enhancing Radioiodine (~(125)I,~(131)I)Uptake in Melanoma Cells

To explore whether transfer of human sodium/iodide symporter (hNIS) gene in vivo can enhance radioiodine uptake in melanoma cells, pcDNA3hNIS and pcDNA3 are transduced into melanoma cells (B16) by electroporation, and two cell lines named B16A and B16B respectively are established. The three cell lines (B16A, B16B, and B16) are injected subcutaneously into the right flank of C57 mice. Biodistribution study and tumor imaging are performed when the tumor reaches approximately 10 mm in diameter. The imaging shows in vivo uptake in expected sites including the salivary glands, thyroid, stomach, and hNIStransduced tumor, whereas the nontransduced tumor is not visualized. The percentage of injected dose per gram(%ID/g) of B16A tumors at 1, 2, 4, 12, 24 h after injection of 125I are 12.22±0.71, 10.91±0.72, 8.73±0.99, 1.24±0.29, and 0.19±0.03 respectively, there are significantly difference between B16A and controlling tumors, P<0.01. However, biological T1/2 is about 6 hours. So, transfer of the hNIS gene can enhance radioiodine uptake in melanoma cells. However, the remaining time in the tumors is not long enough, and a lethal dose of radiation in tumor cells in vivo is too low to be available.