Generation of a Selective Small Molecule Inhibitor of the CBP/p300 Bromodomain for Leukemia Therapy
- Cancer Res. 2015 Dec 1;75(23):5106-5119. doi: 10.1158/0008-5472.CAN-15-0236.
- 1. Nuffield Department of Clinical Medicine, University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
- 2. Nuffield Department of Clinical Medicine, University of Oxford, Ludwig Institute for Cancer Research (LICR), Roosevelt Drive, Oxford OX3 7DQ, UK.
- 3. Nuffield Department of Clinical Medicine, University of Oxford, Target Discovery Institute (TDI), Roosevelt Drive, Oxford OX3 7BN, UK.
- 4. Laboratory of Childhood Leukemia, Department of Biomedicine, University of Basel and Basel University Children's Hospital, Hebelstrasse 20 CH - 4031 Basel, Switzerland.
- 5. Epinova DPU, Immuno-Inflammation Therapy Area Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage SG1 2NY, UK.
- 6. Laboratory of Cancer Biology, Department of Oncology, Medical Sciences Division, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK.
- 7. Gurdon Institute and Department of Pathology, University of Cambridge, Cambridge CB2 1QN, UK.
- 8. Experimental Medicines Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, UK.
- 9. BioSeek Division of DiscoveRx Corporation, 310 Utah Street, Suite 100, South San Francisco, CA, 94080, USA.
- 10. Promega Corporation, 2800 Woods Hollow Road, Madison, Wisconsin, U.S.A 53711.
- # Contributed equally.
The histone acetyltransferases CBP/p300 are involved in recurrent leukemia-associated chromosomal translocations and are key regulators of cell growth. Therefore, efforts to generate inhibitors of CBP/p300 are of clinical value. We developed a specific and potent acetyl-lysine competitive protein-protein interaction inhibitor, I-CBP112, that targets the CBP/p300 bromodomains. Exposure of human and mouse leukemic cell lines to I-CBP112 resulted in substantially impaired colony formation and induced cellular differentiation without significant cytotoxicity. I-CBP112 significantly reduced the leukemia-initiating potential of MLL-AF9(+) acute myeloid leukemia cells in a dose-dependent manner in vitro and in vivo. Interestingly, I-CBP112 increased the cytotoxic activity of BET bromodomain inhibitor JQ1 as well as doxorubicin. Collectively, we report the development and preclinical evaluation of a novel, potent inhibitor targeting CBP/p300 bromodomains that impairs aberrant self-renewal of leukemic cells. The synergistic effects of I-CBP112 and current standard therapy (doxorubicin) as well as emerging treatment strategies (BET inhibition) provide new opportunities for combinatorial treatment of leukemia and potentially Other cancers.