NUP98-KDM5A Fusion Induces Hematopoietic Cell Proliferation and Alters Myelo-Erythropoietic Differentiation

Chromosomal translocations are common in acute myeloid leukemia (AML), causing gene fusions that encode oncogenic proteins. The NUP98 gene participates in chromosomal rearrangements with over 30 fusion partners and comprises 6-10% of de novo cases of pediatric AML. These fusions are associated with poor prognosis in children and adults. Among them, NUP98-KDM5A is further enriched in specific subpopulations, found in 15% of non-Down syndrome acute megakaryoblastic leukemia cases and 20% of pediatric acute erythroleukemia. Despite these associations, the direct impact of NUP98-KDM5A on the growth and differentiation of human hematopoietic cells has not been systemically studied. In this study, we transduced cord blood CD34+ hematopoietic stem and progenitor cells (HSPCs) with NUP98-KDM5A or control lentiviral vectors and examined cell proliferation and differentiation. Exposure to cytokines (SCF, TPO, IL-6, FLT3L, SR-1) selected for CD34+ cell growth, and expression of NUP98-KDM5A increased proliferation rate in liquid culture by 19.4-fold (p To further elucidate NUP98-KDM5A effects on differentiation, cytokine supplements known to drive myeloid differentiation (SCF, TPO, G-CSF, and GM-CSF) were added to culture media, which demonstrated the same disruption in myelo-erythropoiesis based on a 4.0-fold decrease (p To evaluate the leukemic potential of NUP98-KDM5A, cells were injected into NRG-SGM3 mice with NUP98-KDM5A inducing at 12 weeks a rapidly lethal myeloid disease in vivo (97.8% human CD45+ cells vs. 2.3% in control, p In conclusion, the expression of NUP98-KDM5A in HSPCs drives proliferation and alters differentiation to maintain stem cell markers while driving an erythroid phenotype in vitro. Furthermore, this fusion is sufficient to engraft in the bone marrow and spleen of NRG-SGM3 mice in vivo and cause marked splenomegaly. Taken together, these data suggest this model properly recapitulates the human disease phenotype seen in patients expressing NUP98-KDM5A and future functional assays and drug screens may provide important insights into understanding the pathophysiology and pharmacologic vulnerabilities of this fusion class. Disclosures Mullighan: Loxo Oncology: Research Funding; Amgen: Honoraria, Other: speaker, sponsored travel; Illumina: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: sponsored travel; AbbVie: Research Funding; Pfizer: Honoraria, Other: speaker, sponsored travel, Research Funding.