Evaluation of dysregulation of the receptor tyrosine kinases Kit, Flt3, and Met in histiocytic sarcomas of dogs.
OBJECTIVE
To evaluate canine histiocytic sarcoma cell lines and tumor samples for dysregulation of the Kit/stem-cell factor (SCF), Flt3/Flt3 ligand (Flt3L), and Met/hepatocyte growth factor (HGF) receptor tyrosine kinase signaling pathways, as these are known to contribute to the differentiation and survival of normal dendritic cells as well as malignant transformation of dendritic cells in mouse models.


METHODS
4 histiocytic sarcoma tumor cell lines and 35 formalin-fixed histiocytic sarcoma specimens obtained from dogs.


METHODS
Histiocytic sarcoma cell lines were evaluated for expression of Kit/SCF, Flt3/Flt3L, and Met/HGF by use of reverse transcriptase-PCR procedures. Histiocytic sarcoma cell lines and tumor samples were evaluated for mutations in Kit, Flt3, and Met by use of PCR analysis of genomic DNA, followed by both sequencing and fluorescent PAGE for deletions or internal tandem duplications. The ability of the multi-targeted split-kinase inhibitor SU11654 to block proliferation and induce apoptosis of histiocytic sarcoma cell lines was also evaluated.


RESULTS
No mutations in Kit, Flt3, and Met were identified in any of the cell lines or tumor samples evaluated. Furthermore, SU11654 did not induce cell-cycle arrest or apoptosis of histiocytic sarcoma lines, even at supratherapeutic doses.


CONCLUSIONS
These data suggest that dysregulation of Kit/SCF, Flt3/Flt3L, and Met/HGF signaling pathways is unlikely to occur in histiocytic sarcomas of dogs and that inhibitors of the Kit, Flt3, and Met pathways are unlikely to provide clinical benefit to dogs with histiocytic sarcomas.
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Regina
R
Zavodovskaya
Albert T
AT
Liao
Cameron L R
CL
Jones
Becky
B
Yip
May B
MB
Chien
Peter F
PF
Moore
Cheryl A
CA
London
D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D017931:DNA Primers; D004283:Dog Diseases / Q000235:genetics*; D004285:Dogs; D005091:Exons; D015620:Histiocytic Disorders, Malignant / Q000235:genetics / Q000662:veterinary*; D008565:Membrane Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D019859:Proto-Oncogene Proteins c-met / Q000235:genetics*; D012509:Sarcoma / Q000235:genetics / Q000662:veterinary*; D019089:Stem Cell Factor / Q000235:genetics; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics*
D017931:DNA Primers; D008565:Membrane Proteins; D019089:Stem Cell Factor; C084881:flt3 ligand protein; D019009:Proto-Oncogene Proteins c-kit; D019859:Proto-Oncogene Proteins c-met; D051941:fms-Like Tyrosine Kinase 3