α-naphthoflavone-derived cytochrome P450 (CYP)1B1 degraders specific for sensitizing CYP1B1-mediated drug resistance to prostate cancer DU145: Structure activity relationship

We previously discovered extrahepatic cytochrome P450 1B1 (CYP1B1) degraders able to overcome drug resistance toward docetaxel using a PROTACs technology, however, the underexplored structure activity relationships and poor water solubility posed a major hurdle in the development of CYP1B1 degraders. Herein, continuous efforts are made to develop more promising alpha-naphthoflavone (ANF)-derived chimeras for degrading CYP1B1. Guided by the strongest ANF-derived CYP1B1 degrader 3a we ever reported, 17 ANF analogues are designed and synthesized to evaluate the CYP1B1 degradation and resultant resistance reversal. In degrading CYP1B1 and sensitizing drug resistance, 4d with a 1, 5-cis triazole coupling mode at (C3') of B ring of ANF exhibited the similar potency as 3a carrying a 1, 4-trans triazole fragment at (C4') of B ring, but more obvious selectivity of 4d toward CYP1B1 over CYP1A2 is observed. When an oxygen was inserted into the linker of 4d, 4f demonstrated better water solubility, a more potent ability in degrading CYP1B1 and reversing drug resistance, and a promising selectivity. Collectively, a substitution position, an alkyne-azide cyclization and a liker type significantly affect the ability of ANF-thalidomide conjugates in eliminating drug resistance of CYP1B1-expressing DU145 (DU145/CY) cells to docetaxel via targeted CYP1B1 degradation.

Automated summary

Efforts were made to develop promising ANF-derived chimeras for degrading CYP1B1 and overcoming drug resistance. The study showed that modification in the ANF structure and linker type significantly affected the potency of the degraders in eliminating drug resistance in CYP1B1-expressing cells.