Pharmacological targeting of the Wdr5-MLL interaction in C/EBPα N-terminal leukemia
- Nat Chem Biol. 2015 Aug;11(8):571-578. doi: 10.1038/nchembio.1859.
- 1. CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna 1090, Austria.
- 2. Ludwig Boltzmann Institute for Cancer Research, Vienna 1090, Austria.
- 3. Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada.
- 4. Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- 5. Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, ON, M5G 0A3, Canada.
- 6. MRC Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, Oxford OX3 9DS, United Kingdom.
- 7. Department of Hematology, Erasmus University Medical Center, Rotterdam 3015 GE, The Netherlands.
- 8. Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada.
- 9. Department of Laboratory Medicine & Core Facility Genomics, Core Facilities, Medical University Vienna, Vienna 1090, Austria.
- 10. Research Institute of Molecular Pathology (IMP), Vienna 1030, Austria.
- 11. Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada.
- # Contributed equally.
The CEBPA gene is mutated in 9% of patients with acute myeloid leukemia (AML). Selective expression of a short (30-kDa) CCAAT-enhancer binding protein-α (C/EBPα) translational isoform, termed p30, represents the most common type of CEBPA mutation in AML. The molecular mechanisms underlying p30-mediated transformation remain incompletely understood. We show that C/EBPα p30, but not the normal p42 isoform, preferentially interacts with WDR5, a key component of SET/MLL (SET-domain/mixed-lineage leukemia) histone-methyltransferase complexes. Accordingly, p30-bound genomic regions were enriched for MLL-dependent H3K4me3 marks. The p30-dependent increase in self-renewal and inhibition of myeloid differentiation required WDR5, as downregulation of the latter inhibited proliferation and restored differentiation in p30-dependent AML models. OICR-9429 is a new small-molecule antagonist of the Wdr5-MLL interaction. This compound selectively inhibited proliferation and induced differentiation in p30-expressing human AML cells. Our data reveal the mechanism of p30-dependent transformation and establish the essential p30 cofactor WDR5 as a therapeutic target in CEBPA-mutant AML.