title: Leukemogenic potency of the novel FLT3-N676K mutant.
abstract: The novel FMS-like tyrosine kinase 3 (FLT3)-N676K point mutation within the FLT3 kinase domain-1 was recently identified in 6 % of de novo acute myeloid leukemia (AML) patients with inv(16). Because FLT3-N676K was encountered almost exclusively in inv(16) AML, we investigated the transforming potential of FLT3-N676K, the cooperation between FLT3-N676K and core binding factor ß-smooth muscle myosin heavy chain (CBFß-SMMHC) (encoded by the inv(16) chimeric gene CBFB-MYH11) in inducing acute leukemia, and tested the sensitivity of FLT3-N676K-positive leukemic cells to FLT3 inhibitors. Retroviral expression of FLT3-N676K in myeloid 32D cells induced AML in syngeneic C3H/HeJ mice (n = 11/13, median latency 58 days), with a transforming activity similar to FLT3-internal tandem duplication (ITD) (n = 8/8), FLT3-TKD D835Y (n = 8/9), and FLT3-ITD-N676K (n = 9/9) mutations. Three out of 14 (21.4 %) C57BL/6J mice transplanted with FLT3-N676K-transduced primary hematopoietic progenitor cells developed acute leukemia (latency of 68, 77, and 273 days), while no hematological malignancy was observed in the control groups including FLT3-ITD. Moreover, co-expression of FLT3-N676K/CBFß-SMMHC did not promote acute leukemia in three independent experiments (n = 16). In comparison with FLT3-ITD, FLT3-N676K induced much higher activation of FLT3 and tended to trigger stronger phosphorylation of MAPK and AKT. Importantly, leukemic cells carrying the FLT3-N676K mutant in the absence of an ITD mutation were highly sensitive to FLT3 inhibitors AC220 and crenolanib, and crenolanib even retained activity against the AC220-resistant FLT3-ITD-N676K mutant. Taken together, the FLT3-N676K mutant is potent to transform murine hematopoietic stem/progenitor cells in vivo. This is the first report of acute leukemia induced by an activating FLT3 mutation in C57BL/6J mice. Moreover, further experiments investigating molecular mechanisms for leukemogenesis induced by FLT3-N676K mutation and clinical evaluation of FLT3 inhibitors in FLT3-N676K-positive AML seem warranted.
authors.affiliation: Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.|Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany.
authors.forename: Kezhi
authors.initials: K
authors.lastname: Huang
authors.affiliation: Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.|Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Zengkai
authors.initials: Z
authors.lastname: Pan
authors.affiliation: Department of Hematology and Oncology, Medical Center, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.|Internal Medicine II, Hematology and Oncology, University Hospital Jena, Jena, Germany.
authors.forename: Florian H
authors.initials: FH
authors.lastname: Heidel
authors.affiliation: Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Scherr
authors.affiliation: Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Eder
authors.affiliation: Department of Hematology and Oncology, Medical Center, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fischer
authors.affiliation: Institute of Pathology, Hannover Medical School, Hannover, Germany.
authors.forename: Guntram
authors.initials: G
authors.lastname: Büsche
authors.affiliation: Department of Molecular Hematopoiesis, Hannover Medical School, Hannover, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Welte
authors.affiliation: Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: von Neuhoff
authors.affiliation: Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
authors.forename: Arnold
authors.initials: A
authors.lastname: Ganser
authors.affiliation: Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany. li.zhixiong@mh-hannover.de.|Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany. li.zhixiong@mh-hannover.de.
authors.forename: Zhixiong
authors.initials: Z
authors.lastname: Li
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001562:Benzimidazoles / Q000627:therapeutic use; D052160:Benzothiazoles / Q000627:therapeutic use; D016026:Bone Marrow Transplantation; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D015973:Gene Expression Regulation, Leukemic; D020022:Genetic Predisposition to Disease; D005822:Genetic Vectors; D006801:Humans; D007942:Leukemia, Experimental / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D020125:Mutation, Missense; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000637:transplantation; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000502:physiology; D010671:Phenylurea Compounds / Q000627:therapeutic use; D010880:Piperidines / Q000627:therapeutic use; D017354:Point Mutation; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011499:Protein Processing, Post-Translational / Q000235:genetics; D011828:Radiation Chimera; D012190:Retroviridae; D020080:Tandem Repeat Sequences; D019076:Transgenes; D014410:Tumor Stem Cell Assay; D051941:fms-Like Tyrosine Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology
chemical_list: D000970:Antineoplastic Agents; D001562:Benzimidazoles; D052160:Benzothiazoles; C095514:CBFbeta-MYH11 fusion protein; D015514:Oncogene Proteins, Fusion; D010671:Phenylurea Compounds; D010880:Piperidines; D047428:Protein Kinase Inhibitors; C544967:quizartinib; C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3; C577197:crenolanib
keywords: Acute leukemia; FLT3 inhibitors; FLT3 mutations; FLT3-N676K; inv(16)