Herein, systemic structural modifications on the C-3, C-6, and C-17 positions of galeterone led to the discovery of 67-b with the dual functions of AR antagonism and degradation. In vivo, 67-b effectively inhibited the growth of hormone-sensitive organs in the Hershberger assay and exhibited tumor regression in the enzalutamide-resistant (c4-2b-ENZ) xenograft model. These results confirmed 67-b to be a promising AR degrader and antagonist for the treatment of mCRPC patients.
The results obtained indicate that the binding of R-bicalutamide in the two AR monomers induces a great instability in the homodimer, which may determine the monomer's dissociation preventing AR migration into the nucleus and avoiding the transcriptional activity. If the W741L mutation occurs, the homodimer tends to have a behaviour close to the agonistic system where the two monomers are tightly bound, which may explain the effect of the W741L in drug insensitivity from a structural point of view.