Blocking VEGFR-3 suppresses angiogenic sprouting and vascular network formation.
Angiogenesis, the growth of new blood vessels from pre-existing vasculature, is a key process in several pathological conditions, including tumour growth and age-related macular degeneration. Vascular endothelial growth factors (VEGFs) stimulate angiogenesis and lymphangiogenesis by activating VEGF receptor (VEGFR) tyrosine kinases in endothelial cells. VEGFR-3 (also known as FLT-4) is present in all endothelia during development, and in the adult it becomes restricted to the lymphatic endothelium. However, VEGFR-3 is upregulated in the microvasculature of tumours and wounds. Here we demonstrate that VEGFR-3 is highly expressed in angiogenic sprouts, and genetic targeting of VEGFR-3 or blocking of VEGFR-3 signalling with monoclonal antibodies results in decreased sprouting, vascular density, vessel branching and endothelial cell proliferation in mouse angiogenesis models. Stimulation of VEGFR-3 augmented VEGF-induced angiogenesis and sustained angiogenesis even in the presence of VEGFR-2 (also known as KDR or FLK-1) inhibitors, whereas antibodies against VEGFR-3 and VEGFR-2 in combination resulted in additive inhibition of angiogenesis and tumour growth. Furthermore, genetic or pharmacological disruption of the Notch signalling pathway led to widespread endothelial VEGFR-3 expression and excessive sprouting, which was inhibited by blocking VEGFR-3 signals. Our results implicate VEGFR-3 as a regulator of vascular network formation. Targeting VEGFR-3 may provide additional efficacy for anti-angiogenic therapies, especially towards vessels that are resistant to VEGF or VEGFR-2 inhibitors.
Tammela
Tuomas
T
Molecular/Cancer Biology Laboratory and Ludwig Institute for Cancer Research, Biomedicum Helsinki and the Haartman Institute University of Helsinki, PO Box 63 (Haartmaninkatu 8), 00014 Helsinki, Finland.
Zarkada
Georgia
G
Wallgard
Elisabet
E
Murtomäki
Aino
A
Suchting
Steven
S
Wirzenius
Maria
M
Waltari
Marika
M
Hellström
Mats
M
Schomber
Tibor
T
Peltonen
Reetta
R
Freitas
Catarina
C
Duarte
Antonio
A
Isoniemi
Helena
H
Laakkonen
Pirjo
P
Christofori
Gerhard
G
Ylä-Herttuala
Seppo
S
Shibuya
Masabumi
M
Pytowski
Bronislaw
B
Eichmann
Anne
A
Betsholtz
Christer
C
Alitalo
Kari
K
D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D045744:Cell Line, Tumor; D004151:Dipeptides / Q000494:pharmacology; D015536:Down-Regulation; D042783:Endothelial Cells / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008024:Ligands; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D009369:Neoplasms / Q000098:blood supply* / Q000188:drug therapy; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism; D015398:Signal Transduction; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000037:antagonists & inhibitors* / Q000378:metabolism*
D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D004151:Dipeptides; D008024:Ligands; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester; D051880:Receptors, Notch; D040321:Vascular Endothelial Growth Factor Receptor-3