Combined VEGF and PDGF inhibition for neovascular AMD: anti-angiogenic properties of axitinib on human endothelial cells and pericytes in vitro.
OBJECTIVE
Drugs currently approved for neovascular age-related macular degeneration (nAMD) offer anti-VEGF monotherapy only. Platelet-derived growth factor (PDGF) signaling is pivotal to pericyte-induced stabilization of choroidal neovascularizations (CNV), and causes partial anti-VEGF resistance. No combination therapy for VEGF and PDGF has been approved yet. Axitinib is a tyrosine kinase inhibitor interfering with VEGF and PDGF signaling, and has been approved for the treatment of renal cell carcinoma. This study evaluates anti-angiogenic properties of axitinib in an in-vitro model of choroidal neovascularizations in nAMD.


METHODS
Human endothelial cells (HUVEC) and human pericytes (hPC-PL) were treated with axitinib doses ranging from 1.0 ng/ml to 10 μg/ml. Cellular viability and proliferation were assessed with a modified MTT assay. VEGF- and PDGF-stimulated migration was observed in modified Boyden chambers. Formation of capillary structures was evaluated on Cultrex basement membrane.


RESULTS
Proliferation was significantly inhibited in both cell lines in a dose-dependent manner. VEGF and PDGF significantly induced, whereas simultaneous axitinib normalized cellular migration in HUVEC and pericytes. On growth-factor-reduced Cultrex, VEGF induced the formation of capillary structures, while axitinib significantly reverted this effect. Axitinib reduced the amount of vessel associated tissue on full growth factor Cultrex. All effects on both cell lines were observed in non-toxic concentrations of axitinib.


CONCLUSIONS
Axitinib inhibits angiogenesis in endothelial cells and pericytes via VEGFR and PDGFR modulation in vitro. Further studies are needed to elucidate whether axitinib may also improve therapy of CNV in AMD in vivo by interference with pericyte stabilization of pathological vessels.
Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany. jakob.siedlecki@med.uni-muenchen.de.
Jakob
http://orcid.org/0000-0002-0279-4823
J
Siedlecki
Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany.
Christian
C
Wertheimer
Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany.
Armin
A
Wolf
Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany.
Raffael
R
Liegl
Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany.
Claudia
C
Priglinger
Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany.
Siegfried
S
Priglinger
Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany.
Kirsten
K
Eibl-Lindner
D000077784:Axitinib; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D020256:Choroidal Neovascularization / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000473:pathology; D006801:Humans; D007093:Imidazoles / Q000627:therapeutic use*; D007191:Indazoles / Q000627:therapeutic use*; D008268:Macular Degeneration / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D020286:Pericytes / Q000187:drug effects* / Q000473:pathology; D010982:Platelet-Derived Growth Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors* / Q000378:metabolism
D007093:Imidazoles; D007191:Indazoles; D010982:Platelet-Derived Growth Factor; D047428:Protein Kinase Inhibitors; D042461:Vascular Endothelial Growth Factor A; D000077784:Axitinib
Age related macular degeneration; Choroidal neovascularization; PDGF; VEGF