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Flt3 mutations from patients with acute myeloid leukemia induce transformation of 32D cells mediated by the Ras and STAT5 pathways.
- Source :
-
Blood [Blood] 2000 Dec 01; Vol. 96 (12), pp. 3907-14. - Publication Year :
- 2000
-
Abstract
- Somatic mutations of the receptor tyrosine kinase Flt3 consisting of internal tandem duplications (ITD) occur in 20% of patients with acute myeloid leukemia. They are associated with a poor prognosis of the disease. In this study, we characterized the oncogenic potential and signaling properties of Flt3 mutations. We constructed chimeric molecules that consisted of the murine Flt3 backbone and a 510-base pair human Flt3 fragment, which contained either 4 different ITD mutants or the wild-type coding sequence. Flt3 isoforms containing ITD mutations (Flt3-ITD) induced factor-independent growth and resistance to radiation-induced apoptosis in 32D cells. Cells containing Flt3-ITD, but not those containing wild-type Flt3 (Flt3-WT), formed colonies in methylcellulose. Injection of 32D/Flt3-ITD induced rapid development of a leukemia-type disease in syngeneic mice. Flt3-ITD mutations exhibited constitutive autophosphorylation of the immature form of the Flt3 receptor. Analysis of the involved signal transduction pathways revealed that Flt3-ITD only slightly activated the MAP kinases Erk1 and 2 and the protein kinase B (Akt) in the absence of ligand and retained ligand-induced activation of these enzymes. However, Flt3-ITD led to strong factor-independent activation of STAT5. The relative importance of the STAT5 and Ras pathways for ITD-induced colony formation was assessed by transfection of dominant negative (dn) forms of these proteins: transfection of dnSTAT5 inhibited colony formation by 50%. Despite its weak constitutive activation by Flt3-ITD, dnRas also strongly inhibited Flt3-ITD-mediated colony formation. Taken together, Flt3-ITD mutations induce factor-independent growth and leukemogenesis of 32D cells that are mediated by the Ras and STAT5 pathways. (Blood. 2000;96:3907-3914)
- Subjects :
- Acute Disease
Animals
Apoptosis drug effects
Apoptosis radiation effects
Cell Division drug effects
Clone Cells cytology
DNA Replication drug effects
DNA-Binding Proteins metabolism
DNA-Binding Proteins physiology
Female
Humans
Leukemia, Myeloid genetics
Mice
Mice, Inbred C3H
Mitogen-Activated Protein Kinase Kinases metabolism
Mutation
Myeloid Cells drug effects
Myeloid Cells physiology
Neoplasms, Experimental mortality
Neoplasms, Experimental pathology
Proto-Oncogene Proteins metabolism
Proto-Oncogene Proteins c-akt
Receptor Protein-Tyrosine Kinases metabolism
Recombinant Fusion Proteins genetics
Recombinant Fusion Proteins metabolism
Recombinant Fusion Proteins pharmacology
STAT5 Transcription Factor
Signal Transduction drug effects
Tandem Repeat Sequences genetics
Trans-Activators metabolism
Trans-Activators physiology
Transfection
Tumor Cells, Cultured
fms-Like Tyrosine Kinase 3
ras Proteins metabolism
ras Proteins physiology
Cell Transformation, Neoplastic drug effects
Leukemia, Myeloid physiopathology
Milk Proteins
Protein Serine-Threonine Kinases
Proto-Oncogene Proteins genetics
Proto-Oncogene Proteins pharmacology
Receptor Protein-Tyrosine Kinases genetics
Receptor Protein-Tyrosine Kinases pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0006-4971
- Volume :
- 96
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Blood
- Publication Type :
- Academic Journal
- Accession number :
- 11090077