Synthesis and in vitro characterization of ionone-based chalcones as novel antiandrogens effective against multiple clinically relevant androgen receptor mutants

A crucial event in prostate cancer progression is the transition from a hormone-sensitive to a lethal castration-refractory disease state. The antagonist-to-agonist conversion due to mutation in AR is a critical problem with the current clinically used antiandrogens. We aim to identify novel antiandrogens that remain as a pure antagonist even in the mutated ARs. By synthesizing a series of ionone-based chalcones, we have identified a novel chalcone (17) that is a pan-antagonist of the wild type and the clinically relevant T877A, W741C and H874Y mutated ARs in luciferase reporter assays in PC-3 cells. Further, chalcone 17 demonstrates sub-micromolar to low micromolar antiproliferative activity in LNCaP, MDA-PCa-2b, 22Rv1 and C4-2B prostate cancer cells, all of which express mutated ARs and confer resistance to the current clinically used antiandrogens. The results suggest that chalcone 17 could be a good candidate for further pre-clinical development as a novel antiandrogen for advanced prostate cancer.