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

Abstract

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.

A novel microtubule-modulating agent induces mitochondrially driven caspase-dependent apoptosis via mitotic checkpoint activation in human prostate cancer cells

“…It was noteworthy to observe that PC-3 cells, which lack endogenous androgen receptor (AR) expression, were more sensitive to EM011 than LNCaP, C4-2, C4-2B cells, which express various forms of mutated AR and exhibit hypersensitivity to androgen stimulation (34). Recent reports indicate that the microtubule-binding drug, paclitaxel, failed to decrease AR activity in C4-2B cells compared to PC-3 cells (35).…”

Study of the impact of the T877A mutation on ligand‐induced helix‐12 positioning of the androgen receptor resulted in design and synthesis of novel antiandrogens

“…Plasmid pCMV‐AR‐W741C was kindly provided by Drs Eijiro Nakamura and Osmu Ogawa (Kyoto University, Kyoto, Japan). The luciferase‐reporter assays were performed in PC‐3 cells as described previously 11, 24. Briefly, 24 h before transfection, PC‐3 cells was seeded at a density of 6−7 × 10 4 cells per well in 24‐well microtiter plates and subsequently cotransfected with reporter MMTV‐luciferase (pCMV‐MMTV‐Luc), WT or mutant AR‐expressing plasmid and Renilla null luciferase using LipofectamineTM 2000 reagent (Invitrogen) following manufacturer's protocol.…”

Learning From Estrogen Receptor Antagonism: Structure‐Based Identification of Novel Antiandrogens Effective Against Multiple Clinically Relevant Androgen Receptor Mutants

“…The assays were performed as previously described (21). Briefly, PC‐3 cells seeded in 24‐well plates were transiently cotransfected with MMTV‐luciferase reporter, the WT or the mutated AR‐expressing plasmid, and Renilla null luciferase using Lipofectamine™ 2000 reagent according to the manufacturer’s protocol (Invitrogen, Burlington, ON, Canada).…”

“…Significantly, the T877A and W741C mutations were found in patients who experienced treatment failure with flutamide and bicalutamide, respectively (12). To date, a series of novel non‐steroidal antiandrogens have been developed, but reports of antiandrogens circumventing multiple mutant ARs are limited (21–23). In addition, supportive evidence for androgen‐independent activation of the AR via cross talk with factors/cytokines is emerging.…”