Kmt2d deficiency promotes acute myeloid leukemia development and maintenance

The histone-3 lysine-4 methyltransferase KMT2D is frequently mutated in human cancers. However, knowledge of its role in the initiation and maintenance of acute myeloid leukemia (AML) is incomplete. Here, we show that KMT2D is generally downregulated in human AML. Using shRNA and CRISPR/Cas9 technologies, we show that Kmt2d loss, by cooperating with Trp53 and Nf1 loss, promoted mouse acute myeloid leukemogenesis through a differentiation block of hematopoietic stem and progenitor cells. Furthermore, using a doxycycline-induced shRNA system, we show that restoring Kmt2d impairs AML maintenance. Multi-omics analyses of Kmt2d-deficient and -restored AML cells showed that Kmt2d, via histone methyltransferase activity and chromatin remodeling, epigenetically regulates the expression of genes controlling hematopoietic stem cell differentiation. Lastly, we showed that 3-Deazaneplanocin A, a histone methyltransferase EZH2 inhibitor, could specifically repress Kmt2d-deficient AML cell growth and reverse pro-leukemia programs. Thus, our study indicate Kmt2d is a tumor suppressor, whose downregulation promotes AML development through differentiation blockage. RNAseq, ATACseq and CUT&Tag in Kmt2d knockdown, Kmt2d restoration and Kmt2d wild-type bone marrow or hematopoietic stem and progenitor cells.