Enzalutamide has greater affinity to AR than Bicalutamide does in a competition assay with 16β-[F]fluoro-5α-DHT (18-FDHT) in castration-resistant LNCaP/AR cells (AR-overexpressing). While Enzalutamide shows no agonism in LNCaP/AR prostate cells. Enzalutamide antagonizes induction of prostate-specific antigen (PSA) and transmembrane serine protease 2 (TMPRSS2), combination with the synthetic androgen R1881 in parental LNCaP cells. Enzalutamide could inhibit the transcriptional activity of a mutant AR protein (W741C, mutation of Trp to Cys). Enzalutamide also prevents nuclear translocation and co-activator recruitment of the ligand-receptor complex.
In vivo
Enzalutamide induces great tumor regression in castrate male mice bearing LNCaP/AR xenografts at a dose of 10 mg/kg.