CX-5461 is an inhibitor of ribosomal RNA (rRNA) synthesis. It selectively inhibits RNA polymerase I-driven transcription of rRNA in HCT-116, A375, and MIA PaCa-2 tumor cells (IC50s = 142, 113, and 54 nM, respectively) without affecting RNA polymerase II (IC50 > 25μM), DNA replication, or protein translation. At 50 mg/kg, CX-5461 demonstrates in vivo antitumor activity against human solid tumors in mouse xenograft models.
