ABL1 and breast cancer: Similar to the nimbolide-based PROTAC 16, theEN219-based PROTAC 17 demonstrated robust depletion ofBRD4 in 231MFP breast cancer cells with DC50 values of36 and 14 nM for the long and short isoforms of BRD4, respectively.Interestingly, one EN219-based PROTAC 18 (Table 2, entry 18) exhibited preferentialdegradation of BCR-ABL over c-ABL, compared with several previousBCR-ABL degraders recruiting CRBN or VHL that showed opposite selectivity.79