DOT1L inhibitor EPZ-5676 displays synergistic antiproliferative activity in combination with standard of care drugs and hypomethylating agents in MLL-rearranged leukemia cells.

Abstract

EPZ-5676 [(2R,3R,4S,5R)-2-(6-amino-9H-purin-9-yl)-5-((((1r,3S)-3-(2-(5-(tert-butyl)-1H-benzo[d]imidazol-2-yl)ethyl)cyclobutyl)(isopropyl)amino)methyl)tetrahydrofuran-3,4-diol], a small-molecule inhibitor of the protein methyltransferase DOT1L, is currently under clinical investigation for acute leukemias bearing MLL-rearrangements (MLL-r). In this study, we evaluated EPZ-5676 in combination with standard of care (SOC) agents for acute leukemias as well as other chromatin-modifying drugs in cellular assays with three human acute leukemia cell lines: MOLM-13 (MLL-AF9), MV4-11 (MLL-AF4), and SKM-1 (non-MLL-r). Studies were performed to evaluate the antiproliferative effects of EPZ-5676 combinations in a cotreatment model in which the second agent was added simultaneously with EPZ-5676 at the beginning of the assay, or in a pretreatment model in which cells were incubated for several days in the presence of EPZ-5676 prior to the addition of the second agent. EPZ-5676 was found to act synergistically with the acute myeloid leukemia (AML) SOC agents cytarabine or daunorubicin in MOLM-13 and MV4-11 MLL-r cell lines. EPZ-5676 is selective for MLL-r cell lines as demonstrated by its lack of effect either alone or in combination in the nonrearranged SKM-1 cell line. In MLL-r cells, the combination benefit was observed even when EPZ-5676 was washed out prior to the addition of the chemotherapeutic agents, suggesting that EPZ-5676 sets up a durable, altered chromatin state that enhances the chemotherapeutic effects. Our evaluation of EPZ-5676 in conjunction with other chromatin-modifying drugs also revealed a consistent combination benefit, including synergy with DNA hypomethylating agents. These results indicate that EPZ-5676 is highly efficacious as a single agent and synergistically acts with other chemotherapeutics, including AML SOC drugs and DNA hypomethylating agents in MLL-r cells.

• Authors: Christine R Klaus, Dorothy Iwanowicz, Danielle Johnston, Carly A Campbell, Jesse J Smith, Mikel P Moyer, Robert A Copeland, Edward J Olhava, Margaret Porter Scott, Roy M Pollock, Scott R Daigle, Alejandra Raimondi
• Journal: The Journal of pharmacology and experimental therapeutics (J Pharmacol Exp Ther) Vol. 350 Issue 3 Pg. 646-56 (Sep 2014) ISSN: 1521-0103 [Electronic] United States
• PMID: 24993360 (Publication Type: Journal Article)
• Copyright: Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

Chemical References

• Antineoplastic Agents
• Benzimidazoles
• EPZ-5676
• Growth Inhibitors
• DOT1L protein, human
• Methyltransferases
• Histone-Lysine N-Methyltransferase

Topics

• Antineoplastic Agents (administration & dosage)
• Benzimidazoles (administration & dosage)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Drug Synergism
• Growth Inhibitors (administration & dosage)
• Histone-Lysine N-Methyltransferase
• Humans
• Leukemia, Myeloid, Acute (drug therapy, pathology)
• Methylation (drug effects)
• Methyltransferases (antagonists & inhibitors, metabolism)