AOH1996 is an orally active ligand for the replicasome component PCNA (proliferating cell nuclear antigen), targeting the transcription-replication conflict (TRC). It interferes with the interaction of PCNA with its binding proteins, leading to DNA replication stress and apoptosis. AOH1996 causes proteasome-dependent rpb1 degradation and lethal DNA damage by stabilizing the interaction between PCNA and RNA polymerase II, and acts synergistically with DNA damaging agents to inhibit tumor cell growth.