title: Gene expression profiling and candidate gene resequencing identifies pathways and mutations important for malignant transformation caused by leukemogenic fusion genes.
abstract: NUP98-HOXD13 (NHD13) and CALM-AF10 (CA10) are oncogenic fusion proteins produced by recurrent chromosomal translocations in patients with acute myeloid leukemia (AML). Transgenic mice that express these fusions develop AML with a long latency and incomplete penetrance, suggesting that collaborating genetic events are required for leukemic transformation. We employed genetic techniques to identify both preleukemic abnormalities in healthy transgenic mice as well as collaborating events leading to leukemic transformation. Candidate gene resequencing revealed that 6 of 27 (22%) CA10 AMLs spontaneously acquired a Ras pathway mutation and 8 of 27 (30%) acquired an Flt3 mutation. Two CA10 AMLs acquired an Flt3 internal-tandem duplication, demonstrating that these mutations can be acquired in murine as well as human AML. Gene expression profiles revealed a marked upregulation of Hox genes, particularly Hoxa5, Hoxa9, and Hoxa10 in both NHD13 and CA10 mice. Furthermore, mir196b, which is embedded within the Hoxa locus, was overexpressed in both CA10 and NHD13 samples. In contrast, the Hox cofactors Meis1 and Pbx3 were differentially expressed; Meis1 was increased in CA10 AMLs but not NHD13 AMLs, whereas Pbx3 was consistently increased in NHD13 but not CA10 AMLs. Silencing of Pbx3 in NHD13 cells led to decreased proliferation, increased apoptosis, and decreased colony formation in vitro, suggesting a previously unexpected role for Pbx3 in leukemic transformation.
authors.affiliation: Leukemia Biology Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, MD 20892, USA.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Novak
authors.forename: David P
authors.initials: DP
authors.lastname: Harper
authors.forename: David
authors.initials: D
authors.lastname: Caudell
authors.forename: Christopher
authors.initials: C
authors.lastname: Slape
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Beachy
authors.forename: Peter D
authors.initials: PD
authors.lastname: Aplan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D004195:Disease Models, Animal; D020869:Gene Expression Profiling; D015973:Gene Expression Regulation, Leukemic; D055785:Gene Knockdown Techniques; D056426:Genetic Loci; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D007938:Leukemia / Q000235:genetics*; D015470:Leukemia, Myeloid, Acute / Q000235:genetics; D051379:Mice; D009154:Mutation; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins / Q000235:genetics; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics
chemical_list: D018398:Homeodomain Proteins; C000616391:MEIS1 protein, human; C000616392:Meis1 protein, mouse; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; C490797:Tgif1 protein, mouse; C097899:homeobox protein HOXA9; C090466:proto-oncogene protein Pbx3; D051941:fms-Like Tyrosine Kinase 3