Sodium iodide symporter for nuclear molecular imaging and gene ther-apy: From bedside to bench and back

Abstract

Molecular imaging, defined as the visual representation, characterization and quantification of biological processes at the cellular and subcellular levels within intact living organisms, can be obtained by various imaging technologies, including nuclear imaging methods. Imaging of normal thyroid tissue and differentiated thyroid cancer, and treatment of thyroid cancer with radioiodine rely on the expression of the sodium iodide symporter (NIS) in these cells. NIS is an intrinsic membrane protein with 13 transmembrane domains and it takes up iodide into the cytosol from the extracellular fluid. By transferring NIS function to various cells via gene transfer, the cells can be visualized with gamma or positron emitting radioisotopes such as Tc-99m, I-123, I-131, I-124 and F-18 tetrafluoroborate, which are accumulated by NIS. They can also be treated with beta- or alpha-emitting radioisotopes, such as I-131, Re-186, Re-188 and At-211, which are also accumulated by NIS. This article demonstrates the diagnostic and therapeutic applications of NIS as a nuclear reporter gene for trafficking cells and a thera-peutic gene for treating cancers. © Ivyspring International Publisher.