Epigenetic, Genomic, and Functional Characterization of MLL-AF9 Rearranged Acute Myeloid Leukemia
Final Report Abstract
Homeobox (HOX) proteins and the receptor tyrosine kinase FLT3 are frequently highly expressed and mutated in acute myeloid leukemia (AML). Aberrant HOX expression is found in nearly all AMLs that harbor a mutation in the Nucleophosmin (NPM1) gene, and FLT3 is concomitantly mutated in approximately 60% of these cases. Little is known how mutant NPM1 (NPM1mut) cells maintain aberrant gene expression. Here, we demonstrate that the histone modifiers MLL1 and DOT1L control HOX and FLT3 expression and differentiation in NPM1mut AML. Using a CRISPR-Cas9 genome editing domain screen, we show NPM1mut AML to be exceptionally dependent on the menin binding site in MLL1. Pharmacological smallmolecule inhibition of the menin-MLL1 protein interaction had profound anti-leukemic activity in human and murine models of NPM1mut AML. Combined pharmacological inhibition of menin-MLL1 and DOT1L resulted in dramatic suppression of HOX and FLT3 expression, induction of differentiation, and superior activity against NPM1mut leukemia in vitro and in vivo. Taken together the key advances from this DFG-funded project are as follows. (1) Specific chromatin regulatory complexes control leukemogenic gene expression programs, including HOX, MEIS1 and FLT3 expression in NPM1mut leukemia. This opens a new arena of investigation into the control of leukemogenic gene expression by MLL1 and DOT1L complexes in genetic subtypes of AML beyond those with MLL1-rearrangement. (2) Combinatorial small molecule menin-MLL1 and DOT1L inhibition has synergistic on target activity and releases the differentiation block of NPM1mut leukemias. It is likely that this combinatorial approach will be relevant for all AMLs with high level HOX gene expression that represent ~50% of cases. (3) This is the first example of a drug combination regimen to target specific epigenetic drivers that control critical leukemogenic gene expression in NPM1mut leukemia, thereby representing a therapeutic opportunity already available for first clinical testing.
Publications
- Myeloid Leukemia Cells with MLL Partial Tandem Duplication are Sensitive to Pharmacological Inhibition of the H3K79 Methyltransferase DOT1L. Blood (ASH Annual Meeting Abstracts), Nov 2013; 122; 1256
Kühn MWM, Hadler MJ, Daigle SR, Feng Z, Chen CW, Chu SH, Cusan M, Deshpande AJ, Deshpande AA, Sinha AU, Xu H, Krivtsov AV, Pollock RM, and Armstrong SA
- Myeloid Leukemia Cells with MLL Partial Tandem Duplication are Sensitive to Pharmacological Inhibition of the H3K79 Methyltransferase DOT1L. FASEB “Hematologic Malignancies” Meeting 2013, Abstract #29
Kühn MWM, Hadler MJ, Feng Z, Chen CW, Chu SH, Cusan M, Deshpande AA, Deshpande AJ, Sinha AU, Xu H, Zhu N, Krivtsov AV and Armstrong SA
- Designed to kill: novel menin-MLL inhibitors target MLL-rearranged leukemia. Cancer Cell. 2015 Apr 13;27(4):431-3
Kühn MWM, Armstrong SA
(See online at https://doi.org/10.1016/j.ccell.2015.03.012) - MLL partial tandem duplication leukemia cells are sensitive to small molecule DOT1L inhibition Haematologica. 2015 May;100(5):e190-3
Kühn MWM, Hadler MJ, Daigle SR, Koche RP, Krivtsov AV, Olhava EJ, Caligiuri MA, Huang G, Bradner JE, Pollock RM, Armstrong SA
(See online at https://doi.org/10.3324/haematol.2014.115337) - Targeting Chromatin Regulators Inhibits Leukemogenic Gene Expression in NPM1 Mutant Leukemia. Cancer Discovery 6(10); 1–16, 2016
Kühn MWM, Song E, Feng Z, Sinha A, Chen CW, Deshpande AJ, Cusan M, Farnoud N, Mupo A, Grove C, Koche R, Bradner JE, de Stanchina E, Vassiliou GS, Hoshii T, Armstrong SA
(See online at https://doi.org/10.1158/2159-8290.CD-16-0237) - Targeting Chromatin Regulators Inhibits Leukemogenic Gene Expression in NPM1 Mutant Leukemia. European Hematology Association (EHA), Annual Meeting 2016 (S308)
Kühn MWM, Song E, Feng Z, Sinha A, Chen CW, Deshpande AJ, Cusan M, Farnoud N, Mupo A, Grove C, Koche R, Bradner JE, de Stanchina E, Vassiliou GS, Hoshii T, Armstrong SA
