Despite marked progress in the rate of cure among patients with acute leukemia, chromosomal translocations involving the mixed lineage leukemia gene (MLL1) give rise to highly aggressive acute leukemias associated with poor clinical outcomes for pediatric and adult patients. Current treatment options are of limited effectiveness; thus, there is a pressing need for new therapies for this disease. Genetic studies have demonstrated that the histone methyltransferase DOT1L is required for the development and maintenance of MLL-rearranged (MLL-r) leukemia in model systems. Likewise, work from the previous funding cycle clearly defined a role for DOT1L inhibition in MLL-r leukemia through characterization of a potent, specific DOT1L inhibitor, EPZ-5676 (pinometostat), that has remarkably selective anti-proliferative and pro-apoptotic effects on MLL-rearranged cells. As pinometostat has progressed through Phase I clinical trials, responses and subsequent relapses imply the development of acquired resistance to the inhibitor. In this proposal, we seek to understand the biological underpinnings of DOT1L inhibitor resistance and develop a novel class of small molecule DOT1L degraders to overcome resistance.
In Specific Aim 1, we seek to understand the mechanisms of resistance through detailed studies of chromatin structure and gene expression following the development of acquired resistance to DOT1L inhibitor therapy. We will also investigate the non-enzymatic role of DOT1L in MLL-r leukemia and define dependencies acquired in the resistant state.
In Specific Aim 2, we will lead a chemistry and chemical biology campaign and develop an assay platform for the identification and optimization of the first small molecule degraders of endogenous DOT1L protein.
In Specific Aim 3, we will utilize our cell culture and patient-derived xenograft models of MLL-r leukemia to explore the impact of DOT1L degradation on gene expression and tumor progression while driving hit-to-lead optimization of DOT1L degraders that can prompt clinical investigation. We will also test pharmacological hypotheses regarding combinatorial drug action with DOT1L degraders in predictive human models of MLL-r leukemia. We expect these aims to bring new more efficacious, less toxic therapies to children and adults diagnosed with this devastating disease.

Public Health Relevance

Despite recent progress in our understanding of MLL-rearranged (MLL-r) leukemias, the disease remains difficult to cure, establishing an area of significant unmet medical need. While the first targeted therapies against DOT1L, an enzyme important for survival of MLL-r leukemia, have been realized in human clinical trials, early evidence suggests that resistance to these inhibitors has emerged. In this study, we will seek to define the biological foundation for acquired resistance to DOT1L therapy and overcome resistance through the development and optimization of a new class of small molecules that can degrade DOT1L protein, thus developing the tools and fundamental preclinical knowledge to help overcome this devastating disease.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
3R01CA176745-07S1
Application #
9843753
Study Section
Basic Mechanisms of Cancer Therapeutics Study Section (BMCT)
Program Officer
Venkatachalam, Sundaresan
Project Start
2012-09-25
Project End
2023-05-31
Budget Start
2018-06-18
Budget End
2019-05-31
Support Year
7
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Dana-Farber Cancer Institute
Department
Type
DUNS #
076580745
City
Boston
State
MA
Country
United States
Zip Code
02215
Chu, S Haihua; Song, Evelyn J; Chabon, Jonathan R et al. (2018) Inhibition of MEK and ATR is effective in a B-cell acute lymphoblastic leukemia model driven by Mll-Af4 and activated Ras. Blood Adv 2:2478-2490
Brien, Gerard L; Remillard, David; Shi, Junwei et al. (2018) Targeted degradation of BRD9 reverses oncogenic gene expression in synovial sarcoma. Elife 7:
Toska, Eneda; Osmanbeyoglu, Hatice U; Castel, Pau et al. (2017) PI3K pathway regulates ER-dependent transcription in breast cancer through the epigenetic regulator KMT2D. Science 355:1324-1330
Shortt, Jake; Ott, Christopher J; Johnstone, Ricky W et al. (2017) A chemical probe toolbox for dissecting the cancer epigenome. Nat Rev Cancer 17:160-183
Wang, K; Sanchez-Martin, M; Wang, X et al. (2017) Patient-derived xenotransplants can recapitulate the genetic driver landscape of acute leukemias. Leukemia 31:151-158
Winter, Georg E; Mayer, Andreas; Buckley, Dennis L et al. (2017) BET Bromodomain Proteins Function as Master Transcription Elongation Factors Independent of CDK9 Recruitment. Mol Cell 67:5-18.e19
Valerio, Daria G; Xu, Haiming; Eisold, Meghan E et al. (2017) Histone acetyltransferase activity of MOF is required for adult but not early fetal hematopoiesis in mice. Blood 129:48-59
Wan, Liling; Wen, Hong; Li, Yuanyuan et al. (2017) ENL links histone acetylation to oncogenic gene expression in acute myeloid leukaemia. Nature 543:265-269
Erb, Michael A; Scott, Thomas G; Li, Bin E et al. (2017) Transcription control by the ENL YEATS domain in acute leukaemia. Nature 543:270-274
Kühn, Michael W M; Song, Evelyn; Feng, Zhaohui et al. (2016) Targeting Chromatin Regulators Inhibits Leukemogenic Gene Expression in NPM1 Mutant Leukemia. Cancer Discov 6:1166-1181

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