title: Isolated Hoxa9 overexpression predisposes to the development of lymphoid but not myeloid leukemia.
abstract: Hoxa9 is expressed in hematopoietic stem and progenitor cells, although this expression is usually diminished as these cells undergo differentiation. In addition, aberrant expression of Hoxa9 is strongly associated with both T cell and myeloid leukemia in mice and humans. Despite this strong association, enforced expression of Hoxa9 in murine bone marrow or thymus has only shown a modest ability to transform cells. To investigate this question, we used Vav regulatory elements to generate a transgenic mouse that targets Hoxa9 overexpression to all hematopoietic tissues. High-level expression of the Hoxa9 transgene in the hematopoietic compartment was associated with embryonic lethality, as no pups from founders that expressed high levels of the transgene were born live. However, offspring of an additional founder line, which expressed lower levels of Hoxa9, developed a precursor T cell lymphoblastic leukemia/lymphoma, accompanied by spontaneous Notch1 mutations. In contrast to most murine models of leukemia associated with Hoxa9 overexpression, the Vav-Hoxa9 mice did not overexpress other Hoxa cluster genes, mir196b (a microRNA that is embedded in the Hoxa locus), Meis1, or Pbx3. The Hoxa9 transgenic mouse reported in this study provides a suitable system for the study of Hoxa9 collaborators that drive myeloid and lymphoid malignant transformation.
authors: Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors: Sarah H
authors: SH
authors: Beachy
authors: Masahiro
authors: M
authors: Onozawa
authors: Deborah
authors: D
authors: Silverman
authors: Yang Jo
authors: YJ
authors: Chung
authors: Mariela Martinez
authors: MM
authors: Rivera
authors: Peter D
authors: PD
authors: Aplan
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000473:pathology; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D002478:Cells, Cultured / Q000473:pathology; D005260:Female; D015973:Gene Expression Regulation, Leukemic; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D005801:Genes, Homeobox; D005804:Genes, Lethal; D006413:Hematopoietic System / Q000378:metabolism / Q000473:pathology; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015461:Leukemia, Prolymphocytic, T-Cell / Q000235:genetics*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins / Q000235:genetics / Q000502:physiology; D051567:Proto-Oncogene Proteins c-vav / Q000235:genetics; D051881:Receptor, Notch1 / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000502:physiology
chemical_list: D018398:Homeodomain Proteins; C000616391:MEIS1 protein, human; C000616392:Meis1 protein, mouse; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins; C497762:Notch1 protein, mouse; D051567:Proto-Oncogene Proteins c-vav; D051881:Receptor, Notch1; D011993:Recombinant Fusion Proteins; C097899:homeobox protein HOXA9; C088144:HoxA protein