Targeting lysine demethylase 6B ameliorates ASXL1 truncation–mediated myeloid malignancies in preclinical models
Guo Ge, … , Mingjiang Xu, Feng-Chun Yang
Guo Ge, … , Mingjiang Xu, Feng-Chun Yang
Published November 2, 2023
Citation Information: J Clin Invest. 2024;134(1):e163964. https://doi.org/10.1172/JCI163964.
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Research Article Hematology

Targeting lysine demethylase 6B ameliorates ASXL1 truncation–mediated myeloid malignancies in preclinical models

Abstract

ASXL1 mutation frequently occurs in all forms of myeloid malignancies and is associated with aggressive disease and poor prognosis. ASXL1 recruits Polycomb repressive complex 2 (PRC2) to specific gene loci to repress transcription through trimethylation of histone H3 on lysine 27 (H3K27me3). ASXL1 alterations reduce H3K27me3 levels, which results in leukemogenic gene expression and the development of myeloid malignancies. Standard therapies for myeloid malignancies have limited efficacy when mutated ASXL1 is present. We discovered upregulation of lysine demethylase 6B (KDM6B), a demethylase for H3K27me3, in ASXL1-mutant leukemic cells, which further reduces H3K27me3 levels and facilitates myeloid transformation. Here, we demonstrated that heterozygous deletion of Kdm6b restored H3K27me3 levels and normalized dysregulated gene expression in Asxl1Y588XTg hematopoietic stem/progenitor cells (HSPCs). Furthermore, heterozygous deletion of Kdm6b decreased the HSPC pool, restored their self-renewal capacity, prevented biased myeloid differentiation, and abrogated progression to myeloid malignancies in Asxl1Y588XTg mice. Importantly, administration of GSK-J4, a KDM6B inhibitor, not only restored H3K27me3 levels but also reduced the disease burden in NSG mice xenografted with human ASXL1-mutant leukemic cells in vivo. This preclinical finding provides compelling evidence that targeting KDM6B may be a therapeutic strategy for myeloid malignancies with ASXL1 mutations.

Authors

Guo Ge, Peng Zhang, Pinpin Sui, Shi Chen, Hui Yang, Ying Guo, Ivan P. Rubalcava, Asra Noor, Caroline R. Delma, Joel Agosto-Peña, Hui Geng, Edward A. Medina, Ying Liang, Stephen D. Nimer, Ruben Mesa, Omar Abdel-Wahab, Mingjiang Xu, Feng-Chun Yang

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Figure 7

Pharmacologic KDM6B inhibition blocks the growth of ASXL1 mutation–mediated leukemic cells.

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Pharmacologic KDM6B inhibition blocks the growth of ASXL1 mutation–media...
(A) Western blot showing the protein level of KDM6B in leukemia cell lines. (B) Human leukemia cells were treated with various concentrations of GSK-J4 for 72 hours. The viabilities of the cultured cells were measured using CellTiter-Glo luminescent assay. (C) Western blot analysis of H3K27me3 levels in OCI-AML5 cells treated with vehicle (V) or 5 μM GSK-J4 (G) after 24, 48, and 72 hours. (D) ChIP-qPCR showing the levels of H3K27me3 occupancies at the promoter regions of GATA2 and MEIS1. (E) The relative mRNA levels of GATA2 and MEIS1 in OCI-AML5 cells were analyzed by qPCR. (F) Colony-forming assay using primary BM mononuclear cells (BMMNCs) from an MDS patient (ASXL1 G646WfsX12) with or without GSK-J4 treatment. Representative images of colony formation are shown. The images were taken on the 14th day of the assay. (G) Western blot showing the levels of H3K27me3 in primary mononuclear cells from an MDS patient with the treatment of 5 μM GSK-J4 for 72 hours. (H) Kaplan-Meier survival curve representing the survival of K562-transplanted NSG mice treated with DMSO or 50 mg/kg GSK-J4 (n =10 mice per group). (I) Representative H&E staining of femur and liver sections from the mice in H. Scale bars: 100 μm. (J) Kaplan-Meier survival curve for AML PDX #1–transplanted NSG mice treated with DMSO or 50 mg/kg GSK-J4 (n = 7 mice per group). Data were derived from 3–4 independent experiments and represent the mean ± SEM. *P < 0.05, **P < 0.01, and ***P < 0.001, by unpaired Student’s t test (D–F) or log-rank (Mantel-Cox) test (H and J).