title: MLL-ENL-mediated leukemia initiation at the interface of lymphoid commitment.
abstract: Translocations involving the mixed lineage leukemia-1 are recurrent events in acute leukemia and associate with lymphoid (ALL), myeloid (AML) or mixed lineage (MLL) subtypes. Despite an association with ALL in humans, murine MLL fusion models are persistently restricted to AML. We here explored this issue using an inducible mixed lineage leukemia-eleven nineteen leukemia (MLL-ENL) mouse model. Although multiple progenitor cell types with myeloid potential are potent AML leukemia-initiating cells, also the earliest lymphoid progenitors were capable of initiating AML. This ability to evoke a latent myeloid potential in the earliest lymphoid progenitors was lost upon further lymphoid commitment. At the same time, more downstream/committed lymphoid precursors also failed to initiate lymphoid leukemia. Co-expression of MLL-ENL with a constitutively active RAS allele, the most common co-mutation in MLL fusion leukemias, could influence on both disease latency and lineage assignment of developing leukemia in what appears to be a mutation-order-dependent manner. Finally, CEBPB-mediated transdifferentation of committed and otherwise leukemia-incompetent B-cell progenitors imbued these cells with leukemic competence for AML. Therefore, apart from providing detailed insight into the differential responsiveness of candidate target cells to a first-hit MLL fusion event, our data warrants caution to therapeutic approaches based on the concept of transdifferentiation.
authors.affiliation: Molecular Hematology, Institution for Laboratory Medicine, Lund University, Lund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Ugale
authors.affiliation: Molecular Hematology, Institution for Laboratory Medicine, Lund University, Lund, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Säwén
authors.affiliation: Molecular Hematology, Institution for Laboratory Medicine, Lund University, Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Dudenhöffer-Pfeifer
authors.affiliation: Molecular Hematology, Institution for Laboratory Medicine, Lund University, Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Wahlestedt
authors.affiliation: Molecular Hematology, Institution for Laboratory Medicine, Lund University, Lund, Sweden.
authors.forename: G L
authors.initials: GL
authors.lastname: Norddahl
authors.affiliation: Molecular Hematology, Institution for Laboratory Medicine, Lund University, Lund, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Bryder
mesh_terms: D000818:Animals; D002471:Cell Transformation, Neoplastic; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004195:Disease Models, Animal; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics* / Q000378:metabolism; D015456:Leukemia, Biphenotypic, Acute / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D051788:Myeloid-Lymphoid Leukemia Protein / Q000235:genetics* / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014178:Translocation, Genetic
chemical_list: D004268:DNA-Binding Proteins; C493508:Mllt1 protein, mouse; D015514:Oncogene Proteins, Fusion; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase; C497423:Kmt2a protein, mouse