Discovery of Novel CBP/p300 and BRD4 Dual-Target PROTACs with Potent Antitumor Activity in Prostate Cancer

CBP/p300 and BRD4 synergistically drive prostate cancer progression. Here, we report the rational design, synthesis, and biological evaluation of novel PROTACs capable of simultaneously degrading CBP/p300 and BRD4. The representative compounds 10h and 29c induced robust degradation of both targets with DC₅₀ values ranging from 8.8 pM to 10.5 nM in PC-3 prostate cancer cells, accompanied by marked downregulation of c-Myc and acetylated H3K27. Both compounds displayed potent antiproliferative activity across multiple cancer cell lines, with higher potency than NEO2734, paclitaxel (PTX), and ARV-771. In a PC-3 xenograft mouse model, compound 29c achieved dose-dependent tumor growth inhibition (TGI) of up to 81.5% at a low dose of 0.2 mg/kg, administered every other day, significantly surpassing the efficacy of NEO2734 and PTX at higher doses. Together, 29c, a highly efficient CBP/p300 and BRD4 dual-target degrader, demonstrates significant therapeutic potential in prostate cancer and warrants further development.