title: FLT3 mutations in canine acute lymphocytic leukemia.
abstract: BACKGROUND
  FMS-like tyrosine kinase 3 (FLT3) is a commonly mutated protein in a variety of human acute leukemias. Mutations leading to constitutively active FLT3, including internal tandem duplications of the juxtamembrane domain (ITD), result in continuous cellular proliferation, resistance to apoptotic cell death, and a poorer prognosis. A better understanding of the molecular consequences of FLT3 activation would allow improved therapeutic strategies in these patients. Canine lymphoproliferative diseases, including lymphoma and acute leukemias, share evolutionarily conserved chromosomal aberrations and exhibit conserved mutations within key oncogenes when compared to their human counterparts. A small percentage of canine acute lymphocytic leukemias (ALL) also exhibit FLT3 ITD mutations.
  
  
  METHODS
  We molecularly characterized FLT3 mutations in two dogs and one cell line, by DNA sequencing, gene expression analysis via quantitative real-time PCR, and sensitivity to the FLT3 inhibitor lestaurtinib via in vitro proliferation assays. FLT 3 and downstream mediators of FLT3 activation were assessed by Western blotting.
  
  
  RESULTS
  The canine B-cell leukemia cell line, GL-1, and neoplastic cells from 2/7 dogs diagnosed cytologically with ALL were found to have FLT3 ITD mutations and FLT3 mRNA up-regulation. Lestaurtinib, a small molecule FLT3 inhibitor, significantly inhibited the growth of GL-1 cells, while not affecting the growth of two other canine lymphoid cell lines without the FLT3 mutation. Finally, western blots were used to confirm the conserved downstream mediators of FLT3 activating mutations.
  
  
  CONCLUSIONS
  These results show that ALL and FLT3 biology is conserved between canine and human patients, supporting the notion that canine ALL, in conjunction with the GL-1 cell line, will be useful in the development of a relevant large animal model to aid in the study of human FLT3 mutant leukemias.
authors.affiliation: Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, NC, USA.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Suter
authors.forename: George W
authors.initials: GW
authors.lastname: Small
authors.forename: Eric L
authors.initials: EL
authors.lastname: Seiser
authors.forename: Rachael
authors.initials: R
authors.lastname: Thomas
authors.forename: Matthew
authors.initials: M
authors.lastname: Breen
authors.forename: Kristy L
authors.initials: KL
authors.lastname: Richards
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002227:Carbazoles / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D004195:Disease Models, Animal; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005663:Furans; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation / Q000187:drug effects; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050799:STAT5 Transcription Factor / Q000378:metabolism; D051941:fms-Like Tyrosine Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: D002227:Carbazoles; D004273:DNA, Neoplasm; D005663:Furans; D050799:STAT5 Transcription Factor; C119379:lestaurtinib; D051941:fms-Like Tyrosine Kinase 3; D048049:Extracellular Signal-Regulated MAP Kinases