EPZ004777

EPZ004777 is a specific small-molecule H3K79 methyltransferase DOT1L inhibitor that potently inhibits DOT1L in a radionuclide homogeneous assay with the half maximal inhibition concentration IC50 value of 400 pM and selectively kills a variety of MLL-rearranged leukemia cells, including an MLL-AF4 leukemia cell line MV4-11 and an MLL-AF9 leukemia cell line MOLM13 [1 & 2].

EPZ004777 has also been found to selectively inhibit the proliferation of MLL-AF10 and CALM-AF10 transformed cells in a dose dependent manner (IC50: 0.1 μM to 1 μM), in which the mRNA expression levels of two hallmark leukemogenic genes (Hoxa9 and Meis1) are suppressed by EPZ004777 in a concentration dependent manner [2].

Reference

References:
[1] Yu W, Chory EJ, Wernimont AK, Tempel W, Scopton A, Federation A, Marineau JJ, Qi J, Barsyte-Lovejoy D, Yi J, Marcellus R, Iacob RE, Engen JR, Griffin C, Aman A, Wienholds E, Li F, Pineda J, Estiu G, Shatseva T, Hajian T, Al-Awar R, Dick JE, Vedadi M, Brown PJ, Arrowsmith CH, Bradner JE, Schapira M. Catalytic site remodelling of the DOT1L methyltransferase by selective inhibitors. Nat Commun. 2012;3:1288. doi: 10.1038/ncomms2304.
[2] Chen L, Deshpande AJ, Banka D, Bernt KM, Dias S, Buske C, Olhava EJ, Daigle SR, Richon VM, Pollock RM, Armstrong SA. Abrogation of MLL-AF10 and CALM-AF10-mediated transformation through genetic inactivation or pharmacological inhibition of the H3K79 methyltransferase Dot1l. Leukemia. 2013 Apr;27(4):813-22. doi: 10.1038/leu.2012.327. Epub 2012 Nov 9.

Structure-guided DOT1L probe optimization by label-free ligand displacement.[Pubmed:25397901]

ACS Chem Biol. 2015 Mar 20;10(3):667-74.

The DOT1L lysine methyltransferase has emerged as a validated therapeutic target in MLL-rearranged (MLLr) acute leukemias. Although S-adenosylmethionine competitive inhibitors have demonstrated pharmacological proof-of-principle in MLLr-leukemia, these compounds require further optimization to improve cellular potency and pharmacokinetic stability. Limiting DOT1L inhibitor discovery and ligand optimization have been complex biochemical methods often using radionucleotides and cellular methods requiring prolonged culture. We therefore developed a new suite of assay technologies that allows comparative assessment of chemical tools for DOT1L in a miniaturized format. Coupling these assays with structural information, we developed new insights into DOT1L ligand binding and identified several functionalized probes with increased cellular potency (IC50 values approximately 10 nM) and excellent selectivity for DOT1L. Together these assay technologies define a platform capability for discovery and optimization of small-molecule DOT1L inhibitors.

Targeting human SET1/MLL family of proteins.[Pubmed:28160335]

Protein Sci. 2017 Apr;26(4):662-676.

The SET1 family of proteins, and in particular MLL1, are essential regulators of transcription and key mediators of normal development and disease. Here, we summarize the detailed characterization of the methyltransferase activity of SET1 complexes and the role of the key subunits, WDR5, RbBP5, ASH2L, and DPY30. We present new data on full kinetic characterization of human MLL1, MLL3, SET1A, and SET1B trimeric, tetrameric, and pentameric complexes to elaborate on substrate specificities and compare our findings with what has been reported before. We also review exciting recent work identifying potent inhibitors of oncogenic MLL1 function through disruption of protein-protein interactions within the MLL1 complex.

AF10 regulates progressive H3K79 methylation and HOX gene expression in diverse AML subtypes.[Pubmed:25464900]

Cancer Cell. 2014 Dec 8;26(6):896-908.

Homeotic (HOX) genes are dysregulated in multiple malignancies, including several AML subtypes. We demonstrate that H3K79 dimethylation (H3K79me2) is converted to monomethylation (H3K79me1) at HOX loci as hematopoietic cells mature, thus coinciding with a decrease in HOX gene expression. We show that H3K79 methyltransferase activity as well as H3K79me1-to-H3K79me2 conversion is regulated by the DOT1L cofactor AF10. AF10 inactivation reverses leukemia-associated epigenetic profiles, precludes abnormal HOXA gene expression, and impairs the transforming ability of MLL-AF9, MLL-AF6, and NUP98-NSD1 fusions-mechanistically distinct HOX-activating oncogenes. Furthermore, NUP98-NSD1-transformed cells are sensitive to small-molecule inhibition of DOT1L. Our findings demonstrate that pharmacological inhibition of the DOT1L/AF10 complex may provide therapeutic benefits in an array of malignancies with abnormal HOXA gene expression.

DOT1L as a therapeutic target for the treatment of DNMT3A-mutant acute myeloid leukemia.[Pubmed:27335278]

Blood. 2016 Aug 18;128(7):971-81.

Mutations in DNA methyltransferase 3A (DNMT3A) are common in acute myeloid leukemia and portend a poor prognosis; thus, new therapeutic strategies are needed. The likely mechanism by which DNMT3A loss contributes to leukemogenesis is altered DNA methylation and the attendant gene expression changes; however, our current understanding is incomplete. We observed that murine hematopoietic stem cells (HSCs) in which Dnmt3a had been conditionally deleted markedly overexpress the histone 3 lysine 79 (H3K79) methyltransferase, Dot1l. We demonstrate that Dnmt3a(-/-) HSCs have increased H3K79 methylation relative to wild-type (WT) HSCs, with the greatest increases noted at DNA methylation canyons, which are regions highly enriched for genes dysregulated in leukemia and prone to DNA methylation loss with Dnmt3a deletion. These findings led us to explore DOT1L as a therapeutic target for the treatment of DNMT3A-mutant AML. We show that pharmacologic inhibition of DOT1L resulted in decreased expression of oncogenic canyon-associated genes and led to dose- and time-dependent inhibition of proliferation, induction of apoptosis, cell-cycle arrest, and terminal differentiation in DNMT3A-mutant cell lines in vitro. We show in vivo efficacy of the DOT1L inhibitor EPZ5676 in a nude rat xenograft model of DNMT3A-mutant AML. DOT1L inhibition was also effective against primary patient DNMT3A-mutant AML samples, reducing colony-forming capacity (CFC) and inducing terminal differentiation in vitro. These studies suggest that DOT1L may play a critical role in DNMT3A-mutant leukemia. With pharmacologic inhibitors of DOT1L already in clinical trials, DOT1L could be an immediately actionable therapeutic target for the treatment of this poor prognosis disease.

DOT1L inhibitor improves early development of porcine somatic cell nuclear transfer embryos.[Pubmed:28632762]

PLoS One. 2017 Jun 20;12(6):e0179436.

Incomplete epigenetic reprogramming of the genome of donor cells causes poor early and full-term developmental efficiency of somatic cell nuclear transfer (SCNT) embryos. Previous research indicate that inhibition of the histone H3 K79 methyltransferase DOT1L, using a selective pharmacological inhibitor EPZ004777 (EPZ), significantly improved reprogramming efficiency during the generation of mouse induced pluripotent stem cells. However, the roles of DOT1L in porcine nuclear transfer-mediated cellular reprogramming are not yet known. Here we showed that DOT1L inhibition via 0.5 nM EPZ treatment for 12 or 24 h significantly enhanced the blastocyst rate of SCNT embryos and dramatically reduced the level of H3K79me2 during SCNT 1-cell embryonic development. Additionally, H3K79me2 level in the EPZ-treated SCNT embryos was similar to that in in vitro fertilized embryos, suggesting that DOT1L-mediated H3K79me2 is a reprogramming barrier to early development of porcine SCNT embryos. qRT-PCR analysis further demonstrated that DOT1L inactivation did not change the expression levels of DOT1L itself but increased the expression levels of POU5F1, LIN28, SOX2, CDX2 and GATA4 associated with pluripotency and early cell differentiation. In conclusion, DOT1L inhibitor improved early developmental efficiency of porcine SCNT embryos probably via inducing the increased expression of genes important for pluripotency and lineage specification.

Catalytic site remodelling of the DOT1L methyltransferase by selective inhibitors.[Pubmed:23250418]

Nat Commun. 2012;3:1288.

Selective inhibition of protein methyltransferases is a promising new approach to drug discovery. An attractive strategy towards this goal is the development of compounds that selectively inhibit binding of the cofactor, S-adenosylmethionine, within specific protein methyltransferases. Here we report the three-dimensional structure of the protein methyltransferase DOT1L bound to EPZ004777, the first S-adenosylmethionine-competitive inhibitor of a protein methyltransferase with in vivo efficacy. This structure and those of four new analogues reveal remodelling of the catalytic site. EPZ004777 and a brominated analogue, SGC0946, inhibit DOT1L in vitro and selectively kill mixed lineage leukaemia cells, in which DOT1L is aberrantly localized via interaction with an oncogenic MLL fusion protein. These data provide important new insight into mechanisms of cell-active S-adenosylmethionine-competitive protein methyltransferase inhibitors, and establish a foundation for the further development of drug-like inhibitors of DOT1L for cancer therapy.