title: Human somatic PTPN11 mutations induce hematopoietic-cell hypersensitivity to granulocyte-macrophage colony-stimulating factor.
abstract: Juvenile myelomonocytic leukemia (JMML) is a lethal disease of young children characterized by hypersensitivity of hematopoietic progenitors to granulocyte-macrophage colony-stimulating factor (GM-CSF). Mutations in PTPN11, which encodes the protein tyrosine phosphatase Shp-2, are common in JMML. We hypothesized that PTPN11 mutations induce hypersensitivity of hematopoietic progenitors to GM-CSF and confer increased GM-CSF-stimulated phospho-extracellular signal-regulated kinase (Erk) levels. To test this hypothesis, the wild-type (WT) and 3 mutant Ptpn11 cDNAs (E76K, D61V, and D61Y) were transduced into murine bone marrow cells to examine GM-CSF-stimulated granulocyte-macrophage colony-forming unit (CFU-GM) growth, macrophage progenitor proliferation, and activation of the Ras signaling pathway. Expression of the Shp-2 mutants induced progenitor cell hypersensitivity to GM-CSF compared with cells transduced with vector alone or WT Shp-2. Macrophage progenitors expressing the Shp-2 mutants displayed both basal and GM-CSF-stimulated hyperproliferation compared with cells transduced with vector alone or WT Shp-2. Consistently, macrophage progenitors transduced with the Shp-2 mutants demonstrated constitutively elevated phospho-Erk levels and sustained activation of phospho-Erk following GM-CSF stimulation compared with vector alone or WT Shp-2. These data support the hypothesis that PTPN11 mutations induce hematopoietic progenitor hypersensitivity to GM-CSF due to hyperactivation of the Ras signaling axis and provide a basis for the GM-CSF signaling pathway as a target for rational drug design in JMML.
authors.affiliation: Herman B Wells Center for Pediatric Research, 1044 W Walnut St, R4-402, Indianapolis, IN 46202, USA. rchan@iupui.edu
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Chan
authors.forename: Melissa B
authors.initials: MB
authors.lastname: Leedy
authors.forename: Veerendra
authors.initials: V
authors.lastname: Munugalavadla
authors.forename: Cara S
authors.initials: CS
authors.lastname: Voorhorst
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Li
authors.forename: Menggang
authors.initials: M
authors.lastname: Yu
authors.forename: Reuben
authors.initials: R
authors.lastname: Kapur
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism; D049109:Cell Proliferation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D015477:Leukemia, Myelomonocytic, Chronic / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D010766:Phosphorylation; D017354:Point Mutation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D015398:Signal Transduction; D014161:Transduction, Genetic; D018631:ras Proteins / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D048049:Extracellular Signal-Regulated MAP Kinases; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; D018631:ras Proteins