Detection of vascular endothelial growth factor (VEGF) and VEGF receptors Flt-1 and KDR in canine mastocytoma cells.
Vascular endothelial growth factor (VEGF) is a major regulator of angiogenesis and a potential autocrine growth factor for neoplastic cells in various malignancies. In the present study, we have investigated expression of VEGF and VEGF receptors in canine mastocytomas and the canine mastocytoma cell line C2. As assessed by immunostaining of tissue sections and cytospin slides, primary neoplastic mast cells (MC) and C2 cells were found to express the VEGF protein. In Northern blot and RT-PCR experiments, C2 cells expressed VEGF mRNA in a constitutive manner. VEGF mRNA expression in C2 cells was counteracted by LY294002 and rapamycin, suggesting involvement of the PI3-kinase/mTOR pathway. Moreover, C2 cells were found to express VEGF receptor-1 (Flt-1) and VEGF receptor-2 (KDR). However, recombinant VEGF failed to promote (3)H-thymidine uptake in C2 cells, and a neutralizing anti-VEGF antibody (bevacizumab) failed to downregulate spontaneous proliferation in these cells. In addition, rapamycin decreased the expression of VEGF in C2 cells at the mRNA and protein level without suppressing their proliferation. Together, canine mastocytoma cells express VEGF as well as VEGF receptors. However, despite co-expression of VEGF and its receptors, VEGF is not utilized as an autocrine growth regulator by canine mastocytoma cells.
Rebuzzi
Laura
L
Department for Small Animals and Horses, Clinic for Internal Medicine and Infectious Diseases, University of Veterinary Medicine Vienna, Vienna, Austria.
Willmann
Michael
M
Sonneck
Karoline
K
Gleixner
Karoline V
KV
Florian
Stefan
S
Kondo
Rudin
R
Mayerhofer
Matthias
M
Vales
Anja
A
Gruze
Alexander
A
Pickl
Winfried F
WF
Thalhammer
Johann G
JG
Valent
Peter
P
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D015152:Blotting, Northern / Q000662:veterinary; D045744:Cell Line, Tumor; D002867:Chromones / Q000494:pharmacology; D004283:Dog Diseases / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D005434:Flow Cytometry / Q000662:veterinary; D007150:Immunohistochemistry / Q000662:veterinary; D008297:Male; D034801:Mastocytoma / Q000201:enzymology / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012313:RNA / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D020123:Sirolimus / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis* / Q000235:genetics; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000096:biosynthesis* / Q000235:genetics; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis* / Q000235:genetics
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D002867:Chromones; D005419:Flavonoids; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D012313:RNA; D020123:Sirolimus; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one