MLL1 and DOT1L cooperate with meningioma-1 to induce acute myeloid leukemia
Simone S. Riedel, … , Tobias Neff, Kathrin M. Bernt
Simone S. Riedel, … , Tobias Neff, Kathrin M. Bernt
Published April 1, 2016; First published February 29, 2016
Citation Information: J Clin Invest. 2016;126(4):1438-1450. https://doi.org/10.1172/JCI80825.
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Research Article Oncology

MLL1 and DOT1L cooperate with meningioma-1 to induce acute myeloid leukemia

Abstract

Meningioma-1 (MN1) overexpression is frequently observed in patients with acute myeloid leukemia (AML) and is predictive of poor prognosis. In murine models, forced expression of MN1 in hematopoietic progenitors induces an aggressive myeloid leukemia that is strictly dependent on a defined gene expression program in the cell of origin, which includes the homeobox genes Hoxa9 and Meis1 as key components. Here, we have shown that this program is controlled by two histone methyltransferases, MLL1 and DOT1L, as deletion of either Mll1 or Dot1l in MN1-expressing cells abrogated the cell of origin–derived gene expression program, including the expression of Hoxa cluster genes. In murine models, genetic inactivation of either Mll1 or Dot1l impaired MN1-mediated leukemogenesis. We determined that HOXA9 and MEIS1 are coexpressed with MN1 in a subset of clinical MN1hi leukemia, and human MN1hi/HOXA9hi leukemias were sensitive to pharmacologic inhibition of DOT1L. Together, these data point to DOT1L as a potential therapeutic target in MN1hi AML. In addition, our findings suggest that epigenetic modulation of the interplay between an oncogenic lesion and its cooperating developmental program has therapeutic potential in AML.

Authors

Simone S. Riedel, Jessica N. Haladyna, Matthew Bezzant, Brett Stevens, Daniel A. Pollyea, Amit U. Sinha, Scott A. Armstrong, Qi Wei, Roy M. Pollock, Scott R. Daigle, Craig T. Jordan, Patricia Ernst, Tobias Neff, Kathrin M. Bernt

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Figure 6

MN1hi/HOXA9hi Mutz3 cells respond to DOT1L inhibition while several other cell lines with high HOXA9 expression are unaffected.

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MN1hi/HOXA9hi Mutz3 cells respond to DOT1L inhibition while several oth...
(A and B) qPCR for HOXA9 (A) and MN1 (B) in HOXA9 expressing non–MLL-rearranged (non–MLL-r) cell lines: Loucy (early T cell precursor ALL), KG1 (AML), KG1a (AML), and Mutz3 (AML). MLL-rearranged controls: MV4;11 (AML), Molm14 (AML). Negative control (NC): Jurkat. Each bar represents fold-change compared with Molm14 (set to 1); n = 3. Two-sided t test Dot1l–/– vs. Dot1lfl/fl. Error bars represent ±SEM; *P < 0.01 (ANOVA). (C) Western blot showing H3K79 dimethylation in Loucy, Mutz3, KG1, and KG1a cell lines exposed to the indicated concentration of the DOT1L inhibitor EPZ004777 (EPZ). KG1/KG1a cell lines exposed to the indicated concentration of the DOT1L inhibitor EPZ in the presence or absence of verapamil (Ver) or cyclosporine A (CSA). KG1 and KG1a express high levels of the efflux pump ABCB1/MDR1/P-GP, requiring blockade of the drug transported with verapamil or CSA to achieve efficient decrease in H3K79 methylation. (D) IGV tracks of Loucy, Mutz3, and Molm14 (Molm) treated with DMSO control (C) or 2 μM EPZ (E) over the HOXA9 locus confirm complete reduction of H3K79 dimethylation to background levels in treated cells. (E–G) Exposure of Loucy (E), KG1 and KG1a (F) to EPZ at the indicated concentrations. Shown are fold-expansion over a 14-day culture period (serial cell counts and Trypan Blue staining; n = 3 independent experiments performed in duplicate; two-sided t test; error bars represent ±SEM). (G–J) Exposure of Mutz3 to EPZ at the indicated concentrations. Shown are fold-expansion over a 14-day culture period (serial cell counts and Trypan Blue staining) (G), apoptosis (Annexin staining) (H), cell cycle (% cells in S-phase, EdU incorporation) (I), and HOXA9 expression (qPCR, fold change compared with DMSO set to 1) (J). n = 3 independent experiments performed in duplicate. Two-sided t test. Error bars represent ±SEM; *P < 0.05, **P < 0.01.