Add Publication. PARP1 is an abundant nuclear protein that is involved in a number of biological processes linked to cellular stress responses. PARP1 inhibitors (PARPi) are known to kill tumor cells via two mechanisms (PARP1 catalytic inhibition and PARP1 trapping). In this work we discovered a PROTAC degrader of PARP1 -180055, which uncoupled PARP1 trapping and inhibition. Moreover, 180055 has great potential for treating cancers.