RUNX1 loss renders hematopoietic and leukemic cells dependent on IL-3 and sensitive to JAK inhibition
Amy C. Fan, … , Purvesh Khatri, Ravindra Majeti
Amy C. Fan, … , Purvesh Khatri, Ravindra Majeti
Published August 15, 2023
Citation Information: J Clin Invest. 2023;133(19):e167053. https://doi.org/10.1172/JCI167053.
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Research Article Hematology Inflammation Article has an altmetric score of 13

RUNX1 loss renders hematopoietic and leukemic cells dependent on IL-3 and sensitive to JAK inhibition

Abstract

Disease-initiating mutations in the transcription factor RUNX1 occur as germline and somatic events that cause leukemias with particularly poor prognosis. However, the role of RUNX1 in leukemogenesis is not fully understood, and effective therapies for RUNX1-mutant leukemias remain elusive. Here, we used primary patient samples and a RUNX1-KO model in primary human hematopoietic cells to investigate how RUNX1 loss contributes to leukemic progression and to identify targetable vulnerabilities. Surprisingly, we found that RUNX1 loss decreased proliferative capacity and stem cell function. However, RUNX1-deficient cells selectively upregulated the IL-3 receptor. Exposure to IL-3, but not other JAK/STAT cytokines, rescued RUNX1-KO proliferative and competitive defects. Further, we demonstrated that RUNX1 loss repressed JAK/STAT signaling and rendered RUNX1-deficient cells sensitive to JAK inhibitors. Our study identifies a dependency of RUNX1-mutant leukemias on IL-3/JAK/STAT signaling, which may enable targeting of these aggressive blood cancers with existing agents.

Authors

Amy C. Fan, Yusuke Nakauchi, Lawrence Bai, Armon Azizi, Kevin A. Nuno, Feifei Zhao, Thomas Köhnke, Daiki Karigane, David Cruz-Hernandez, Andreas Reinisch, Purvesh Khatri, Ravindra Majeti

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Figure 4

RUNX1 KO sensitizes to IL-3 rescue of proliferation and competitive defects.

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RUNX1 KO sensitizes to IL-3 rescue of proliferation and competitive defe...
(A) CD34+ HDR HSPCs were plated in stem retention media and supplemented with 4 or 20 ng/mL IL-3. Cell count was determined at 6 days by flow cytometry using CountBright beads. n = 3 CB. Two-way ANOVA, Šidák’s multiple-comparison test: *P < 0.05. (B) CD34+ HDR HSPCs were labeled with CellTrace Violet and plated in stem retention media with or without 10 ng/mL IL-3. CellTrace MFI was determined after 4 days. n = 3 CB. Two-way ANOVA, Šidák’s multiple-comparison test: *P < 0.05. (C) pSTAT5+ cells were gated based on isotype controls and quantified in CD34+ HDR HSPCs plated in stem retention media with or without 10 ng/mL IL-3 after 7 days. n = 4 CB. Two-way ANOVA, Šidák’s multiple-comparison test: *P < 0.05. (D) CD34+ HDR HSPCs were injected intrafemorally into sublethally irradiated NSGS mice, and hCD45+HDR+ engraftment was evaluated upon sacrifice (at 24–26 weeks after transplantation). n = 4 CB, 7–8 mice. Unpaired t test. (E) CD34+ HDR HSPCs were injected intrafemorally into sublethally irradiated NSGS mice and hCD45+HDR+ engraftment monitored over time using bone marrow aspirates (at 8–10 weeks or 16–18 weeks after transplantation) and upon sacrifice (at 24–26 weeks after transplantation). n = 3 CB, 16 mice. Two-way ANOVA: *P < 0.05. (F) AAVS1 and RUNX1-KO cells were injected in a 1:1 ratio intrafemorally into sublethally irradiated NSGS mice and relative engraftment at 18 weeks was ascertained using bone marrow aspirates. n = 3 CB, 13 mice. Paired t test.