Photosensitizers in Urology and Potential of Sunitinib, a Tyrosine Kinase Inhibitor, as a Photosensitizer through Drug Repositioning

Abstract

A major photosensitizer in urology is protoporphyrin IX (PpIX), which is induced by 5-aminolevulinic acid (5-ALA) and used for photodynamic diagnosis (PDD) of non-muscle invasive bladder cancer (NMIBC). In recent years, evidence for the therapeutic efficacy of PDD-assisted transurethral resection of bladder tumor (TURBT) has also been reported. In addition, as robotic-assisted devices equipped with near-infrared fluorescence imaging systems become more widely used, it is expected that the application and development of photosensitizers that emit near-infrared fluorescence, including indocyanine green (ICG), which is used for intraoperative fluorescence imaging of blood vessels and lymph vessels, will expand. Finally, sunitinib, which has long been used as a tyrosine kinase inhibitor (TKI) for renal cancer, has also been shown to have photosensitizer properties. This article outlines the current status of 5-ALA and ICG and the efficacy of sunitinib against human renal cancer cell lines in vitro.