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: Kezhi Huang, Min Yang, Zengkai Pan, Florian H Heidel, Michaela Scherr, Matthias Eder, Thomas Fischer, Guntram Büsche, Karl Welte, Nils von Neuhoff, Arnold Ganser, Zhixiong Li
• Journal: Annals of hematology (Ann Hematol) Vol. 95 Issue 5 Pg. 783-91 (Apr 2016) ISSN: 1432-0584 [Electronic] Germany
• PMID: 26891877 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Benzimidazoles
• Benzothiazoles
• CBFbeta-MYH11 fusion protein
• Oncogene Proteins, Fusion
• Phenylurea Compounds
• Piperidines
• Protein Kinase Inhibitors
• quizartinib
• FLT3 protein, human
• fms-Like Tyrosine Kinase 3
• crenolanib

Topics

• Amino Acid Substitution
• Animals
• Antineoplastic Agents (therapeutic use)
• Benzimidazoles (therapeutic use)
• Benzothiazoles (therapeutic use)
• Bone Marrow Transplantation
• Cell Transformation, Neoplastic (genetics)
• Gene Expression Regulation, Leukemic
• Genetic Predisposition to Disease
• Genetic Vectors
• Humans
• Leukemia, Experimental (drug therapy, enzymology, genetics)
• Mice
• Mice, Inbred C3H
• Mice, Inbred C57BL
• Mutation, Missense
• Neoplasm Transplantation
• Neoplastic Stem Cells (transplantation)
• Oncogene Proteins, Fusion (genetics, physiology)
• Phenylurea Compounds (therapeutic use)
• Piperidines (therapeutic use)
• Point Mutation
• Protein Kinase Inhibitors (therapeutic use)
• Protein Processing, Post-Translational (genetics)
• Radiation Chimera
• Retroviridae
• Tandem Repeat Sequences
• Transgenes
• Tumor Stem Cell Assay
• fms-Like Tyrosine Kinase 3 (antagonists & inhibitors, genetics, physiology)