title: Establishment of canine hemangiosarcoma xenograft models expressing endothelial growth factors, their receptors, and angiogenesis-associated homeobox genes.
abstract: BACKGROUND
  Human hemangiosarcoma (HSA) tends to have a poor prognosis; its tumorigenesis has not been elucidated, as there is a dearth of HSA clinical specimens and no experimental model for HSA. However, the incidence of spontaneous HSA is relatively high in canines; therefore, canine HSA has been useful in the study of human HSA. Recently, the production of angiogenic growth factors and their receptors in human and canine HSA has been reported. Moreover, the growth-factor environment of HSA is very similar to that of pathophysiological angiogenesis, which some homeobox genes regulate in the transcription of angiogenic molecules. In the present study, we established 6 xenograft canine HSA tumors and detected the expression of growth factors, their receptors, and angiogenic homeobox genes.
  
  
  METHODS
  Six primary canine HSAs were xenografted to nude mice subcutaneously and serially transplanted. Subsequently, the expressions of vascular endothelial growth factor (VEGF)-A, basic fibroblast growth factors (bFGF), flt-1 and flk-1 (receptors of VEGF-A), FGFR-1, and angiogenic homeobox genes HoxA9, HoxB3, HoxB7, HoxD3, Pbx1, and Meis1 were investigated in original and xenograft tumors by histopathology, immunostaining, and reverse transcription polymerase chain reaction (RT-PCR), using canine-specific primer sets.
  
  
  RESULTS
  Histopathologically, xenograft tumors comprised a proliferation of neoplastic cells that were varied in shape, from spindle-shaped and polygonal to ovoid; some vascular-like structures and vascular clefts of channels were observed, similar to those in the original tumors. The expression of endothelial markers (CD31 and vWF) was detected in xenograft tumors by immunohistochemistry and RT-PCR. Moreover, the expression of VEGF-A, bFGF, flt-1, flk-1, FGFR-1, HoxA9, HoxB3, HoxB7, HoxD3, Pbx1, and Meis1 was detected in xenograft tumors. Interestingly, expressions of bFGF tended to be higher in 3 of the xenograft HSA tumors than in the other tumors.
  
  
  CONCLUSIONS
  We established 6 xenograft canine HSA tumors in nude mice and found that the expressions of angiogenic growth factors and their receptors in xenograft HSAs were similar to those in spontaneous HSA. Furthermore, we detected the expression of angiogenic homeobox genes; therefore, xenograft models may be useful in analyzing malignant growth in HSA.
authors.affiliation: Laboratory of Veterinary Pathology, Department of Veterinary Medicine, Gifu University, Gifu, Japan. l5102402@edu.gifu-u.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kodama
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sakai
authors.forename: Satoko
authors.initials: S
authors.lastname: Matsuura
authors.forename: Mami
authors.initials: M
authors.lastname: Murakami
authors.forename: Atsuko
authors.initials: A
authors.lastname: Murai
authors.forename: Takashi
authors.initials: T
authors.lastname: Mori
authors.forename: Kouji
authors.initials: K
authors.lastname: Maruo
authors.forename: Tohru
authors.initials: T
authors.lastname: Kimura
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Masegi
authors.forename: Tokuma
authors.initials: T
authors.lastname: Yanai
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006394:Hemangiosarcoma / Q000235:genetics* / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000235:genetics* / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000235:genetics* / Q000378:metabolism; D014183:Transplantation, Heterologous; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D051496:Receptor, Fibroblast Growth Factor, Type 1; D040262:Receptors, Vascular Endothelial Growth Factor