A novel strategy of transferring NIS protein to cells using extracellular vesicles leads to increase in iodine uptake and cytotoxicity

BACKGROUND: This study was designed to explore a novel approach for transferring NIS protein to cells using extracellular vesicle (EV) and enhancing iodine avidity in hepatocellular carcinoma (HCC) cells. METHODS: We transfected the HCC cells (Huh7) with NIS gene, designated as Huh7/NIS, and isolated the EVs from them. Presence of NIS protein in EVs and EV-mediated transport of NIS protein to recipient Huh7 cells were tested using Western blotting. We also examined radioiodine uptake in Huh7 cells treated with EV-Huh7/NIS. RESULTS: Successful transfer of NIS protein into Huh7 cells was confirmed by WB and microscopy. EVs showed high levels of NIS protein in them. Treatment of Huh7 cells with EV-Huh7/NIS increased the NIS protein level and enhanced (125)I uptake in recipient Huh7 cells. In addition, EV-huh7/NIS pre-treatment enhanced the cytotoxicity of (131)I therapy against Huh7 cells by inducing increased DNA damage/increased γH2A.X foci formation. CONCLUSION: This is the first-of-its-kind demonstration of successful transportation of the NIS protein to cells via EVs, which increased radioiodine uptake. This approach can revert radioiodine-resistant cancers into radioiodine-sensitive cancers.