Modified biphenyl Hsp90 C-terminal inhibitors for the treatment of cancer.

Heat Shock Protein 90 (Hsp90) is a molecular chaperone under clinical investigation for the treatment of neurodegenerative diseases and cancer. Neuroprotective Hsp90 C-terminal inhibitors (novologues) contain a biaryl ring system, and include KU-596, which was modified and investigated for potential anti-cancer activity. Incorporation of a benzamide group onto the biaryl novologues in lieu of the acetamide yielded compounds that manifest anti-cancer activity. Further exploration of the central phenyl ring led to compounds with enhanced anti-proliferative activity. The design, synthesis, and evaluation of these new analogs against breast and prostate cancer cell lines is reported herein, where it was found that 8b and 10 manifest potent anti-proliferative activity and a robust degradation of Hsp90 client-dependent proteins.