Hematopoietic Stem Cell (HSC)-Independent Progenitors Are Susceptible to Mll-Af9-Induced Leukemic Transformation

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  • Cristiana Barone
  • Roberto Orsenigo
  • Cazzola, Anna
  • Elisabetta D’Errico
  • Arianna Patelli
  • Giulia Quattrini
  • Barbara Vergani
  • Silvia Bombelli
  • Sofia De Marco
  • Cristina D’Orlando
  • Cristina Bianchi
  • Biagio Eugenio Leone
  • Raffaella Meneveri
  • Andrea Biondi
  • Giovanni Cazzaniga
  • Terence Howard Rabbitts
  • Silvia Brunelli
  • Emanuele Azzoni

Infant acute myeloid leukemia (AML) is a heterogeneous disease, genetically distinct from its adult counterpart. Chromosomal translocations involving the KMT2A gene (MLL) are especially common in affected infants of less than 1 year of age, and are associated with a dismal prognosis. While these rearrangements are likely to arise in utero, the cell of origin has not been conclusively identified. This knowledge could lead to a better understanding of the biology of the disease and support the identification of new therapeutic vulnerabilities. Over the last few years, important progress in understanding the dynamics of fetal hematopoiesis has been made. Several reports have highlighted how hematopoietic stem cells (HSC) provide little contribution to fetal hematopoiesis, which is instead largely sustained by HSC-independent progenitors. Here, we used conditional Cre-Lox transgenic mouse models to engineer the Mll-Af9 translocation in defined subsets of embryonic hematopoietic progenitors. We show that embryonic hematopoiesis is generally permissive for Mll-Af9-induced leukemic transformation. Surprisingly, the selective introduction of Mll-Af9 in HSC-independent progenitors generated a transplantable myeloid leukemia, whereas it did not when introduced in embryonic HSC-derived cells. Ex vivo engineering of the Mll-Af9 rearrangement in HSC-independent progenitors using a CRISPR/Cas9-based approach resulted in the activation of an aberrant myeloid-biased self-renewal program. Overall, our results demonstrate that HSC-independent hematopoietic progenitors represent a permissive environment for Mll-Af9-induced leukemic transformation, and can likely act as cells of origin of infant AML.

Original languageEnglish
Article number3624
JournalCancers
Volume15
Issue number14
Number of pages19
ISSN2072-6694
DOIs
Publication statusPublished - 2023
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2023 by the authors.

    Research areas

  • cell of origin, CRISPR/Cas9, erythro-myeloid progenitors, hematopoiesis, hematopoietic stem cell, infant AML, Mll-Af9

ID: 362688832