Cancer gene therapy: Prospects of using human sodium iodide symporter gene in non-thyroidal cancer

Gene therapy is one of the promising therapeutic strategies evolved rapidly in the frontier of translational biology in cancer. To overcome the off target effect of conventional cancer therapies it is the most flourishing approach in present epoch. Various researches in this context are ongoing to eradicate devastating cancer cells with minimal or no side effects. Of the various gene therapy protocols developed, a set of genes called suicide genes, are being actively pursued as potential strategy. Briefly, this strategy involves tumor targeted delivery of a therapy/reporter gene to convert a systematically administered pro-drug into a cytotoxic drug which in turn induces tumor cell death. Additionally, advancement in small animal imaging modalities facilitates real-time monitoring of the delivered transgene by using appropriate imaging probe developed against the transgene. Non-invasive monitoring helps to realize precise transgene delivery and also aid to understand therapy response. In this background, we have reviewed potential suicide genes frequently explored for cancer treatment, which supports both diagnostic and therapeutic applications with special emphasis on sodium iodide symporter (NIS). Apart from its natural expression in thyroid, NIS protein expression has raised the possibility of using radioiodide therapy and diagnosis in few non-thyroidal cancers as well. In this review, we also covered various challenges to get NIS gene therapeutics from bench to bedside in various non-thyroidal cancers.