Discovery of Potent 2-Aryl-6,7-dihydro-5H-pyrrolo[1,2-a]imidazoles as WDR5-WIN-Site Inhibitors Using Fragment-Based Methods and Structure-Based Design

WDR5is a chromatin-regulatory scaffold proteinoverexpressed in various cancers and a potential epigenetic drug target for the treatment of mixed-lineage leukemia. Here, we describe the discovery of potent and selective WDR5-WIN-site inhibitors using fragment-based methods and structure-based design. NMR-based screening of a large fragment library identified several chemically distinct hit series that bind to the WIN site within WDR5. Members of a 6,7-dihydro-5H-pyrrolo[1,2-a]imidazole fragment class were expanded using a structure-based design approach to arrive at lead compoundswith dissociation constants<10 nM and micromolar cellular activity against an AML-leukemia cell line. These compounds represent starting points for the discovery of clinically useful WDR5inhibitors for the treatment of cancer.