Design, synthesis, and biological evaluation of 4H-pyran-4-one-based CYP11A1 inhibitors

This study addresses persistent androgen receptor signaling in castration-resistant prostate cancer by developing novel CYP11A1-directed compounds that target the first step of steroid hormone biosynthesis. Based on the clinical-stage inhibitor Opevesostat, 26 analogues were designed and synthesized by modifying the aromatic or pyranone core, cyclic amine linker, sulfonyl substituent, and hydrophobic fragment. Compound IIA-1 showed 96.2% inhibition at 500 nM and an estimated IC₅₀ of 25.2 nM (95% CI, 9.0-41.4 nM) in the KGN cell-based assay; Opevesostat gave an IC₅₀ of 20.4 nM (95% CI, 12.3-28.5 nM) under the same assay conditions. The docking protocol reproduced the crystallographic cholesterol pose with an RMSD of 0.45 Å. Using this docking setup, molecular docking generated a predicted binding pose for IIA-1, with hydrogen-bonding, π-π, and hydrophobic contacts that provide a structural hypothesis for the observed activity. In a preliminary single-concentration screen against five major drug-metabolizing CYP isoforms, I-8 showed low numerical inhibition across the panel; these data do not establish CYP isoform selectivity. The results define preliminary structure-activity relationships and identify IIA-1 as a preliminary hit for further direct biochemical, selectivity, pharmacokinetic, and in vivo evaluation.