Small-Molecule Inhibition of the Acyl-Lysine Reader ENL as a Strategy against Acute Myeloid Leukemia

The chromatin reader eleven-nineteen leukemia (ENL) has been identifi ed as a critical dependency in acute myeloid leukemia (AML), but its therapeutic potential remains unclear. We describe a potent and orally bioavailable small-molecule inhibitor of ENL, TDI-11055, which displaces ENL from chromatin by blocking its YEATS domain interaction with acylated histones. Cell lines and primary patient samples carrying MLL rearrangements or NPM1 mutations are responsive to TDI-11055. A CRISPR-Cas9-mediated mutagenesis screen uncovers an ENL mutation that confers resistance to TDI-11055, validating the compound's on-target activity. TDI-11055 treat-ment rapidly decreases chromatin occupancy of ENL-associated complexes and impairs transcription elongation, leading to suppression of key oncogenic gene expression programs and induction of dif-ferentiation. In vivo treatment with TDI-11055 blocks disease progression in cell line- and patient -derived xenograft models of MLL-rearranged and NPM1-mutated AML. Our results establish ENL displacement from chromatin as a promising epigenetic therapy for molecularly defi ned AML subsets and support the clinical translation of this approach.SIGNIFICANCE: AML is a poor-prognosis disease for which new therapeutic approaches are desper-ately needed. We developed an orally bioavailable inhibitor of ENL, demonstrated its potent effi cacy in MLL-rearranged and NPM1-mutated AML, and determined its mechanisms of action. These biological and chemical insights will facilitate both basic research and clinical translation.