title: Gain-of-function mutations in the extracellular domain of KIT are common in canine mast cell tumors.
abstract: In the current study, we examined the types and frequency of KIT mutations in mast cell tumors from 191 dogs. Sequencing of reverse transcription-PCR products revealed alterations in 50 (26.2%) of the dogs. Most mutations were in exon 11 (n = 32), and of these, most were internal tandem duplications (n = 25) between residues 571 and 590. Within exon 11, there were two hotspots for mutations at codons 555-559 and 571-590. In addition, nine dogs had mutations in exon 8 and eight had mutations in exon 9. We selected the two most common mutants and two representative exon 11 mutants for further analysis. When expressed in Ba/F3 cells, they were constitutively tyrosine phosphorylated and induced growth factor-independent cell proliferation. AG1296, a tyrosine kinase inhibitor, dose dependently inhibited both the tyrosine phosphorylation of these mutants and their induction of growth factor-independent proliferation. This study shows that activating mutations in not only exon 11 but also exons 8 and 9 are common in canine mast cell tumors. These results also show that Ba/F3 cells can be used for the direct characterization of canine KIT mutants, eliminating the need to make equivalent mutations in the mouse or human genes.
authors.affiliation: Institut National de la Sante et de la Recherche Medicale, U891, Centre de Recherche en Cancérologie de Marseille, Molecular and Functional Hematopoiesis, Marseille F-13009, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Letard
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
authors.forename: Katia
authors.initials: K
authors.lastname: Hanssens
authors.forename: Fabienne
authors.initials: F
authors.lastname: Palmérini
authors.forename: Phillip S
authors.initials: PS
authors.lastname: Leventhal
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Guéry
authors.forename: Alain
authors.initials: A
authors.lastname: Moussy
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Kinet
authors.forename: Olivier
authors.initials: O
authors.lastname: Hermine
authors.forename: Patrice
authors.initials: P
authors.lastname: Dubreuil
mesh_terms: D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004285:Dogs; D005110:Extracellular Space / Q000737:chemistry*; D005260:Female; D005434:Flow Cytometry; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D008024:Ligands; D008297:Male; D008415:Mastocytosis / Q000235:genetics* / Q000473:pathology / Q000662:veterinary*; D051379:Mice; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D011110:Polymorphism, Genetic; D017434:Protein Structure, Tertiary; D019009:Proto-Oncogene Proteins c-kit / Q000737:chemistry* / Q000235:genetics*; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D050505:Mutant Proteins; D020032:Tyrphostins; C106250:6,7-dimethoxy-3-phenylquinoxaline; D019000:Phosphotyrosine; D019009:Proto-Oncogene Proteins c-kit