PF-NIS

PF-NIS is an engineered variant of the human sodium/iodide symporter (NIS) protein designed for targeted internal radiation therapy (TIRT) in extrathyroidal cancers, primarily prostate cancer. By incorporating two specific amino acid substitutions (L253P and V254F) near the substrate cavity, PF-NIS is modified to transport oxyanions such as perrhenate (186/188ReO4-) and pertechnetate (99mTcO4-) while losing the ability to transport iodide (I-). This selectivity allows for the treatment of tumors expressing PF-NIS with radioactive perrhenate while simultaneously protecting the thyroid gland from radiation damage through the administration of non-radioactive iodide, which the thyroid's endogenous wild-type NIS will sequester. In preclinical models, PF-NIS is delivered via gene transfer (e.g., polyplex-mediated plasmid delivery) under a tissue-specific promoter like PSA to ensure localized expression in prostate cancer cells.

Other names

engineered human sodium/iodide symporterL253P/V254F NIS