niclosamide-PROTAC 4

Niclosamide-PROTAC 4 is a proteolysis-targeting chimera (PROTAC) designed to target the androgen receptor (AR) for degradation. It consists of niclosamide, acting as the AR ligand, conjugated to VHL-032, a ligand for the Von Hippel-Lindau (VHL) E3 ubiquitin ligase. While intended to function as a degrader to treat castration-resistant prostate cancer, research indicates that the compound suppresses the proliferation of certain prostate cancer cell lines (PC-3, LNCaP, and 22Rv1) through mechanisms other than AR degradation, as it failed to reduce AR protein levels in Western Blot assays at concentrations up to 1 µM.