Open AccessJournal Article
Anti-Vascular endothelial growth factor treatment augments tumor radiation response under normoxic or hypoxic conditions.
C. G. Lee,M. Heijn,E. di Tomaso,G. Griffon-Etienne,Marek Ancukiewicz,Chieko Koike,K. R. Park,Napoleone Ferrara,Rakesh K. Jain,Herman D. Suit,Yves Boucher +10 more
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The inhibition of the growth of U87 and LS174T tumors by the anti-VEGF mAb was associated with a significant reduction in tumor vascular density and a relatively small increase in the number of apoptotic cells.Abstract:
Recent studies in experimental animals have shown that combining antiangiogenic therapy with radiation can enhance tumor response. Whether this enhancement is mainly attributable to angiogenesis inhibition, endothelial cell radiosensitivity, tumor cell apoptosis, or a decrease in the number of hypoxic cells (improved oxygenation) is not known. We designed this study to discern the role of tumor oxygenation. We chose an anti-vascular endothelial growth factor (anti-VEGF) monoclonal antibody (mAb) which has a known target, human VEGF. We also measured interstitial fluid pressure (IFP) to test the hypothesis that the decreased vascular permeability induced by the anti-VEGF mAb can lower IFP. The effect of anti-VEGF mAb on vascular density, partial oxygen tension (pO2), and apoptosis was also measured. Athymic NCr/Sed nu/nu mice bearing 6-mm xenograft of the human glioblastoma multiforme (U87), or colon adenocarcinoma (LS174T) were treated with anti-VEGF mAb injected i.p. on alternate days for a total of six injections at a dosage of 100 microg/injection/mouse. For combined anti-VEGF and radiation, single radiation doses were given under normal blood flow (20 and 30 Gy) or clamped hypoxic conditions (30 and 40 Gy) 24 h after the sixth injection of mAb. The inhibition of the growth of U87 and LS174T tumors by the anti-VEGF mAb was associated with a significant reduction in tumor vascular density and a relatively small increase in the number of apoptotic cells. Compared with size-matched controls, IFP decreased by 74% in LS174T, and 73% in U87 in mice treated with anti-VEGF mAb. After antibody treatment PO2 increased significantly in U87, but did not change in LS174T tumors. Combined treatment induced in U87 tumors a tumor-growth delay (TGD) which was greater than additive; in LS174T except for the 40-Gy hypoxic group, the effect was only additive. In both U87 and LS174T the TGD induced by the antibody was independent of oxygen levels in the tumor at the time of radiation. The fact that the increase in TGD occurred under both normoxic and hypoxic conditions suggests that anti-VEGF mAb treatment can compensate for the resistance to radiation induced by hypoxia.read more
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The biology of VEGF and its receptors.
TL;DR: Vascular endothelial growth factor (VEGF) is a key regulator of physiological angiogenesis during embryogenesis, skeletal growth and reproductive functions and is implicated in pathologicalAngiogenesis associated with tumors, intraocular neovascular disorders and other conditions.
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Normalization of Tumor Vasculature: An Emerging Concept in Antiangiogenic Therapy
TL;DR: Emerging evidence supporting an alternative hypothesis is reviewed—that certain antiangiogenic agents can also transiently “normalize” the abnormal structure and function of tumor vasculature to make it more efficient for oxygen and drug delivery.
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Vascular endothelial growth factor: basic science and clinical progress.
TL;DR: Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen in vitro and an angiogenic inducer in a variety of in vivo models and is implicated in intraocular neovascularization associated with diabetic retinopathy and age-related macular degeneration.
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Role of the Vascular Endothelial Growth Factor Pathway in Tumor Growth and Angiogenesis
Daniel J. Hicklin,Lee M. Ellis +1 more
TL;DR: Recently, an anti-VEGF antibody (bevacizumab), when used in combination with chemotherapy, was shown to significantly improve survival and response rates in patients with metastatic colorectal cancer and thus, validate VEGF pathway inhibitors as an important new treatment modality in cancer therapy.
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Delivering nanomedicine to solid tumors
TL;DR: In this paper, the authors review the barriers to the delivery of cancer therapeutics and summarize strategies that have been developed to overcome these barriers and discuss design considerations for optimizing the nanoparticles to tumors.
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Selective ablation of immature blood vessels in established human tumors follows vascular endothelial growth factor withdrawal
TL;DR: It is shown that blood vessels in both a xenografted tumor and primary human tumors contain a sizable fraction of immature blood vessels that have not yet recruited periendothelial cells, suggesting that the unique dependence on VEGF of blood vessels lacking periENDothelial Cells can be exploited to reduce an existing tumor vasculature.
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