Targeting LMO2-induced autocrine FLT3 signaling to overcome chemoresistance in early T-cell precursor acute lymphoblastic leukemia

Leukemia. 2025 Mar;39(3):577-589. doi: 10.1038/s41375-024-02491-5. Epub 2025 Jan 23.

Abstract

Early T-cell Precursor Acute Lymphoblastic Leukemia (ETP-ALL) is an immature subtype of T-cell acute lymphoblastic leukemia (T-ALL) commonly show deregulation of the LMO2-LYL1 stem cell transcription factors, activating mutations of cytokine receptor signaling, and poor early response to intensive chemotherapy. Previously, studies of the Lmo2 transgenic mouse model of ETP-ALL identified a population of stem-like T-cell progenitors with long-term self-renewal capacity and intrinsic chemotherapy resistance linked to cellular quiescence. Here, analyses of Lmo2 transgenic mice, patient-derived xenografts, and single-cell RNA-sequencing data from primary ETP-ALL identified a rare subpopulation of leukemic stem cells expressing high levels of the cytokine receptor FLT3. Despite a highly proliferative state, these FLT3-overexpressing cells had long-term self-renewal capacity and almost complete resistance to chemotherapy. Chromatin immunoprecipitation and assay for transposase-accessible chromatin sequencing demonstrated FLT3 and its ligand may be direct targets of the LMO2 stem-cell complex. Media conditioned by Lmo2 transgenic thymocytes revealed an autocrine FLT3-dependent signaling loop that could be targeted by the FLT3 inhibitor gilteritinib. Consequently, gilteritinib impaired in vivo growth of ETP-ALL and improved the sensitivity to chemotherapy. Furthermore, gilteritinib enhanced response to the BCL2 inhibitor venetoclax, which may enable "chemo-free" treatment of ETP-ALL. Together, these data provide a cellular and molecular explanation for enhanced cytokine signaling in LMO2-driven ETP-ALL beyond activating mutations and a rationale for clinical trials of FLT3 inhibitors in ETP-ALL.

MeSH terms

  • Adaptor Proteins, Signal Transducing* / genetics
  • Adaptor Proteins, Signal Transducing* / metabolism
  • Animals
  • Autocrine Communication* / drug effects
  • DNA-Binding Proteins* / genetics
  • DNA-Binding Proteins* / metabolism
  • Drug Resistance, Neoplasm* / drug effects
  • Humans
  • LIM Domain Proteins* / genetics
  • LIM Domain Proteins* / metabolism
  • Mice
  • Mice, Transgenic
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / metabolism
  • Neoplastic Stem Cells / pathology
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma* / drug therapy
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma* / genetics
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma* / metabolism
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma* / pathology
  • Proto-Oncogene Proteins* / genetics
  • Proto-Oncogene Proteins* / metabolism
  • Signal Transduction / drug effects
  • fms-Like Tyrosine Kinase 3* / genetics
  • fms-Like Tyrosine Kinase 3* / metabolism

Substances

  • LIM Domain Proteins
  • fms-Like Tyrosine Kinase 3
  • Adaptor Proteins, Signal Transducing
  • LMO2 protein, human
  • Proto-Oncogene Proteins
  • FLT3 protein, human
  • DNA-Binding Proteins
  • Lmo2 protein, mouse