title: The Colony-Stimulating Factor 3 Receptor T640N Mutation Is Oncogenic, Sensitive to JAK Inhibition, and Mimics T618I.
abstract: OBJECTIVE
  Colony-stimulating factor 3 receptor (CSF3R) mutations have been identified in the majority of chronic neutrophilic leukemia (CNL) and a smaller percentage of atypical chronic myeloid leukemia (aCML) cases. Although CSF3R point mutations (e.g., T618I) are emerging as key players in CNL/aCML, the significance of rarer CSF3R mutations is unknown. In this study, we assess the importance of the CSF3R T640N mutation as a marker of CNL/aCML and potential therapeutic target.
  
  
  METHODS
  Sanger sequencing of leukemia samples was performed to identify CSF3R mutations in CNL and aCML. The oncogenicity of the CSF3R T640N mutation relative to the T618I mutation was assessed by cytokine independent growth assays and by mouse bone marrow transplant. Receptor dimerization and O-glycosylation of the mutants was assessed by Western blot, and JAK inhibitor sensitivity was assessed by colony assay.
  
  
  RESULTS
  Here, we identify a CSF3R T640N mutation in two patients with CNL/aCML, one of whom was originally diagnosed with MDS and acquired the T640N mutation upon evolution of disease to aCML. The T640N mutation is oncogenic in cellular transformation assays and an in vivo mouse bone marrow transplantation model. It exhibits many similar phenotypic features to T618I, including ligand independence and altered patterns of O-glycosylation--despite the transmembrane location of T640 preventing access by GalNAc transferase enzymes. Cells transformed by the T640N mutation are sensitive to JAK kinase inhibition to a similar degree as cells transformed by CSF3R T618I.
  
  
  CONCLUSIONS
  Because of its similarities to CSF3R T618I, the T640N mutation likely has diagnostic and therapeutic relevance in CNL/aCML.
authors.affiliation: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington. Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon.
authors.forename: Julia E
authors.initials: JE
authors.lastname: Maxson
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon.
authors.forename: Samuel B
authors.initials: SB
authors.lastname: Luty
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon.
authors.forename: Jason D
authors.initials: JD
authors.lastname: MacManiman
authors.affiliation: Division of Hematology, Department of Medicine, Stanford University School of Medicine/Stanford Cancer Institute, Stanford, California.
authors.forename: Jason C
authors.initials: JC
authors.lastname: Paik
authors.affiliation: Division of Hematology, Department of Medicine, Stanford University School of Medicine/Stanford Cancer Institute, Stanford, California.
authors.forename: Jason
authors.initials: J
authors.lastname: Gotlib
authors.affiliation: Division of Hematology, Department of Medicine, Stanford University School of Medicine/Stanford Cancer Institute, Stanford, California.
authors.forename: Peter
authors.initials: P
authors.lastname: Greenberg
authors.affiliation: McFarland Clinic, Ames, Iowa.
authors.forename: Swaleh
authors.initials: S
authors.lastname: Bahamadi
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon.
authors.forename: Samantha L
authors.initials: SL
authors.lastname: Savage
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon.
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Abel
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Eide
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, Oregon.
authors.forename: Marc M
authors.initials: MM
authors.lastname: Loriaux
authors.affiliation: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.
authors.forename: Emily A
authors.initials: EA
authors.lastname: Stevens
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon. Department of Cell, Developmental & Cancer Biology, Oregon Health & Science University, Portland, Oregon. tynerj@ohsu.edu.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Tyner
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001853:Bone Marrow / Q000473:pathology; D016026:Bone Marrow Transplantation; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism; D003062:Codon; D004252:DNA Mutational Analysis; D004195:Disease Models, Animal; D005260:Female; D006031:Glycosylation; D006801:Humans; D053612:Janus Kinases / Q000037:antagonists & inhibitors*; D007938:Leukemia / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D008024:Ligands; D008297:Male; D051379:Mice; D008875:Middle Aged; D009154:Mutation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D016184:Receptors, Colony-Stimulating Factor / Q000235:genetics* / Q000378:metabolism
chemical_list: C517047:CSF3R protein, human; D003062:Codon; D008024:Ligands; D047428:Protein Kinase Inhibitors; D016184:Receptors, Colony-Stimulating Factor; D053612:Janus Kinases