PROTAC BRD4 Degrader-11 (compound 9a) is a PROTAC connected by ligands for von Hippel-Lindau and BRD4. PROTAC BRD4 Degrader-11 can be conjugated with STEAP1 and CLL1 antibodies to degrade the BRD4 protein in PC3 prostate cancer cells, with a DC50 of 0.23 nM and 0.38 nM, respectively.