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Identifying and characterizing a novel activating mutation of the FLT3 tyrosine kinase in AML.

Identifying and characterizing a novel activating mutation of the FLT3 tyrosine kinase in AML.

Authors :
Jiang J
Paez JG
Lee JC
Bo R
Stone RM
DeAngelo DJ
Galinsky I
Wolpin BM
Jonasova A
Herman P
Fox EA
Boggon TJ
Eck MJ
Weisberg E
Griffin JD
Gilliland DG
Meyerson M
Sellers WR
Source :
Blood [Blood] 2004 Sep 15; Vol. 104 (6), pp. 1855-8. Date of Electronic Publication: 2004 Jun 03.
Publication Year :
2004

Abstract

The FLT3 receptor is activated by juxtamembrane insertion mutations and by activation loop point mutations in patients with acute myeloid leukemia (AML). In a systematic tyrosine kinase gene exon resequencing study, 21 of 24 FLT3 exons were sequenced in samples from 53 patients with AML, 9 patients with acute lymphoblastic leukemia (ALL), and 3 patients with myelodysplasia samples. Three patients had novel point mutations at residue N841 that resulted in a change to isoleucine in 2 samples and to tyrosine in 1 sample. Introduction of FLT3-N841I cDNA into Ba/F3 cells led to interleukin-3 (IL-3)-independent proliferation, receptor phosphorylation, and constitutive activation of signal transducer and activator of transcription 5 (STAT5) and extracellular regulatory kinase (ERK), suggesting that the N841I mutation confers constitutive activity to the receptor. An FLT3 inhibitor (PKC412) inhibited the growth of Ba/F3-FLT3N841I cells (IC(50) 10 nM), but not of wild-type Ba/F3 cells cultured with IL-3. PKC412 also reduced tyrosine phosphorylation of the mutant receptor and inhibited STAT5 phosphorylation. Examination of the FLT3 autoinhibited structure showed that N841 is the key residue in a hydrogen-bonding network that likely stabilizes the activation loop. These results suggest that mutations at N841 represent a significant new activating mutation in patients with AML and that patients with such mutations may respond to small-molecule FLT3 inhibitors such as PKC412.

Details

Language :
English
ISSN :
0006-4971
Volume :
104
Issue :
6
Database :
MEDLINE
Journal :
Blood
Publication Type :
Academic Journal
Accession number :
15178581
Full Text :
https://doi.org/10.1182/blood-2004-02-0712