Discovery of 5-Nitro-<i>N</i>-(3-(trifluoromethyl)phenyl) Pyridin-2-amine as a Novel Pure Androgen Receptor Antagonist against Antiandrogen Resistance

The transformation of clinical androgen receptor (AR) antagonists into agonists driven by AR mutations poses a significant challenge in treating prostate cancer (PCa). Novel anti-AR therapeutics combating mutation-induced resistance are required. Herein, by combining structure-based virtual screening and biological evaluation, a high-affinity agonist <b>E10</b> was first discovered. Then guided by the representative conformation of State 1 at the free energy landscape, the structural optimization of <b>E10</b> was performed, and pure AR antagonists <b>EL15</b> (IC₅₀ = 0.94 μM) and <b>EF2</b> (IC₅₀ = 0.30 μM) were successfully identified. Both can antagonize wild-type and variant drug-resistant ARs. Therein, <b>EF2</b> demonstrated potent inhibition of the AR pathway and effectively suppressed tumor growth in a C4-2B xenograft mouse model following oral administration. Further molecular dynamics simulation and mutagenesis studies revealed atomic insights into the mode of action of <b>EF2</b> which may serve as a novel lead compound for developing therapeutics against AR-driven PCa.