Selective androgen receptor degrader (SARD) to overcome antiandrogen resistance in castration-resistant prostate cancer

Clinical resistance such as androgen receptor (AR) mutation, AR overexpression, and AR splice variants (ARVs) restrict the second-generation antiandrogens benefit in patients with castration-resistant prostate cancer (CRPC). Several strategies have been implemented to develop novel antiandrogens to circumvent the occurring resistance. In this study, based on rational drug design, we discovered and identified a bifunctional small molecule Z15 as a potent AR antagonist and AR selective degrader. Z15 could directly bind to the AR ligand-binding domain (LBD) and inhibited DHT-induced AR nuclear translocation. Furthermore, Z15 promoted AR degradation through the proteasome pathway. As a result, our in vitro and in vivo studies showed Z15 efficiently suppressed AR and AR mutant transcription activity, downregulated mRNA and protein levels of AR target genes, as well as overcame AR LBD mutations, AR amplification, and ARVs-induced resistance in CRPC. In conclusion, our data illustrate the synergistic importance of AR antagonism and degradation in advanced prostate cancer treatment.