6533b7d1fe1ef96bd125d912

RESEARCH PRODUCT

Identification of a novel activating mutation (Y842C) within the activation loop of FLT3 in patients with acute myeloid leukemia (AML).

Hubert ServeAlois GratwohlEli EsteyGerhard EhningerHarald GschaidmeierThomas FischerThomas KindlerGary J. SchillerChristoph HuberConstan Mueller-tidowStephen D. NimerVirginia M. KlimekFrank BreitenbuecherFrancis J. GilesEric J. FeldmanChunaram ChoudharyPamela S. CohenStefan Kasper

subject

Models MolecularImmunologyBiologymedicine.disease_causeBiochemistryCell Linechemistry.chemical_compoundMicefluids and secretionshemic and lymphatic diseasesProto-Oncogene ProteinsmedicineSTAT5 Transcription FactorAnimalsHumansTyrosinePhosphotyrosineMutationCell CycleMyeloid leukemiaReceptor Protein-Tyrosine Kinaseshemic and immune systemsTyrosine phosphorylationCell BiologyHematologymedicine.diseaseMilk ProteinsProtein Structure TertiaryDNA-Binding ProteinsEnzyme ActivationLeukemiaLeukemia Myeloid AcutechemistryGene Expression Regulationfms-Like Tyrosine Kinase 3embryonic structuresFms-Like Tyrosine Kinase 3MutationCancer researchTrans-ActivatorsTyrosineSignal transductionTyrosine kinaseSignal Transduction

description

Fms-like tyrosine kinase 3 (FLT3) receptor mutations as internal tandem duplication (ITD) or within the kinase domain are detected in up to 35% of patients with acute myeloid leukemia (AML). N-benzoyl staurosporine (PKC412), a highly effective inhibitor of mutated FLT3 receptors, has significant antileukemic efficacy in patients with FLT3-mutated AML. Mutation screening of FLT3 exon 20 in AML patients (n = 110) revealed 2 patients with a novel mutation (Y842C) within the highly conserved activation loop of FLT3. FLT3-Y842C-transfected 32D cells showed constitutive FLT3 tyrosine phosphorylation and interleukin 3 (IL-3)-independent growth. Treatment with PKC412 led to inhibition of proliferation and apoptotic cell death. Primary AML blasts bearing FLT3-Y842C mutations showed constitutive FLT3 and signal transducer and activator of transcription 5 (STAT-5) tyrosine phosphorylation. Ex vivo PKC412 treatment of primary blasts resulted in suppression of constitutive FLT3 and STAT-5 activation and apoptotic cell death. Inspection of the FLT3 structure revealed that Y842 is the key residue in regulating the switch from the closed to the open (= active) conformation of the FLT3 activation loop. Overall, our data suggest that mutations at Y842 represent a significant new activating mutation in AML blasts. Since FLT3 tyrosine kinase inhibitors (TKIs) such as PKC412 are currently being investigated in clinical trials in AML, extended sequence analysis of FLT3 may be helpful in defining the spectrum of TKI-sensitive FLT3 mutations in AML.

10.1182/blood-2004-02-0660https://pubmed.ncbi.nlm.nih.gov/15345593