title: Therapeutic potential of endothelin inhibitors in canine hemangiosarcoma.
abstract: OBJECTIVE
  Hemangiosarcoma (HSA) that originates from vascular endothelial cells is the most common splenic malignant neoplasm in dogs, as it accounts for approximately 20% of all canine soft tissue sarcomas. In this study, inhibitory effects of endothelin receptor antagonists on the growth of HSA cells were examined using cell lines established from canine HSA.
  
  
  METHODS
  The preproendothelin-1 (PPET-1), endothelin type A receptor (ETA) and endothelin type B receptor (ETB) mRNA expression levels in HSA cell lines (n=5) were analyzed quantitatively by real-time RT-PCR. These levels were compared with those in HSA tissues (n=11) and those in normal splenic tissues (n=6). ETA and ETB protein expression was examined by western blot. The production and secretion of endothelin-1 (ET-1) and big ET-1 by cell lines were analyzed by measuring the levels in the culture medium by ELISA. The inhibitory effects of endothelin receptor antagonists (ambrisentan, BQ788 and bosentan) on cell growth were evaluated by WST-8 assay.
  
  
  RESULTS
  The PPET1 and ETA mRNA expression levels were elevated in HSA tissues and HSA cell lines compared with normal tissues. In cell lines, the production of ET-1 and big ET-1 peptide as well as the expression of ETA protein were detected, but the levels of ETB were not measured. Ambrisentan and bosentan inhibited growth activity in cell lines. Ambrisentan was more effective than bosentan.
  
  
  CONCLUSIONS
  These findings demonstrate the importance of the ETA axis in canine HSA as well as the potential of ETA inhibitors in the treatment of canine HSA.
authors.affiliation: Veterinary Internal Medicine, Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Fukumoto
authors.affiliation: Institute for Biomedical Research, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan.
authors.forename: Kaname
authors.initials: K
authors.lastname: Saida
authors.affiliation: Veterinary Pathology, Joint Department of Veterinary Medicine, Gifu University, Gifu 501-1112, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sakai
authors.affiliation: Veterinary Surgery, Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueno
authors.affiliation: Veterinary Biochemistry, Department of Basic Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
authors.forename: Hidetomo
authors.initials: H
authors.lastname: Iwano
authors.affiliation: Department of Veterinary Surgery, Faculty of Veterinary Medicine, Tokyo University of Agriculture and Technology (TUAT), Fuchu, Tokyo 183-8509, Japan. Electronic address: uchide@cc.tuat.ac.jp.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Uchide
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use*; D049109:Cell Proliferation / Q000187:drug effects; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004317:Doxorubicin / Q000008:administration & dosage / Q000494:pharmacology; D065128:Endothelin Receptor Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D019332:Endothelin-1 / Q000235:genetics; D006394:Hemangiosarcoma / Q000188:drug therapy / Q000662:veterinary*; D010666:Phenylpropionates / Q000008:administration & dosage / Q000494:pharmacology; D011724:Pyridazines / Q000008:administration & dosage / Q000494:pharmacology; D044022:Receptor, Endothelin A / Q000235:genetics; D044023:Receptor, Endothelin B / Q000235:genetics
chemical_list: D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D010666:Phenylpropionates; D011724:Pyridazines; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D004317:Doxorubicin; C467894:ambrisentan
keywords: Dog; Endothelin-1; Hemangiosarcoma; Tumor