Abstract
The recent landmark Phase III clinical trial with a VEGF-specific antibody suggests that antiangiogenic therapy must be combined with cytotoxic therapy for the treatment of solid tumors. However, there are no guidelines for optimal scheduling of these therapies. Here we show that VEGFR2 blockade creates a "normalization window"--a period during which combined radiation therapy gives the best outcome. This window is characterized by an increase in tumor oxygenation, which is known to enhance radiation response. During the normalization window, but not before or after it, VEGFR2 blockade increases pericyte coverage of brain tumor vessels via upregulation of Ang1 and degrades their pathologically thick basement membrane via MMP activation.
MeSH Terms
Angiogenesis Inhibitors/therapeutic use
Angiopoietin-1/physiology
Animals
Antibodies, Monoclonal/pharmacology,therapeutic use
Antigens/analysis
Apoptosis/drug effects,radiation effects
Basement Membrane/drug effects,metabolism,pathology
Blood Vessels/chemistry,drug effects,radiation effects
Blotting, Western
Brain Neoplasms/drug therapy,metabolism,radiotherapy
Cell Line, Tumor
Cell Movement/drug effects
Collagen Type IV/analysis,genetics,metabolism
Combined Modality Therapy/methods
Dipeptides/pharmacology
Ephrin-B2/genetics
Fluorescein Angiography
Gamma Rays/therapeutic use
Gene Expression Regulation, Neoplastic/drug effects
Glioma/drug therapy,metabolism,radiotherapy
Humans
Immunohistochemistry
Male
Matrix Metalloproteinase Inhibitors
Matrix Metalloproteinases/metabolism
Mice
Mice, Nude
Models, Biological
Neovascularization, Pathologic/drug therapy,radiotherapy
Oligonucleotide Array Sequence Analysis
Oxygen/metabolism
Pericytes/chemistry,cytology,physiology
Proteoglycans/analysis
Receptor, TIE-2/antagonists & inhibitors,immunology
Time Factors
Transfection
Up-Regulation/genetics
Vascular Endothelial Growth Factor Receptor-2/antagonists & inhibitors,immunology,metabolism
Xenograft Model Antitumor Assays
Chemicals
Angiogenesis Inhibitors
Angiopoietin-1
Antibodies, Monoclonal
Antigens
Collagen Type IV
Dipeptides
Ephrin-B2
Matrix Metalloproteinase Inhibitors
N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide
Proteoglycans
chondroitin sulfate proteoglycan 4
Receptor, TIE-2
Vascular Endothelial Growth Factor Receptor-2
Matrix Metalloproteinases
Oxygen
Authors & Affiliations
12 authors, click to expand affiliations / ORCID
Winkler Frank
E.L. Steele Laboratory for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, 100 Blossom Street, Boston, MA 02114, USA.
Kozin Sergey V
Tong Ricky T
Chae Sung-Suk
Booth Michael F
Garkavtsev Igor
Xu Lei
Hicklin Daniel J
Fukumura Dai
di Tomaso Emmanuelle
Munn Lance L
Jain Rakesh K