ABSTRACT
The growth of new and extensive vascular networks is highly significant in metastatic cancer. The sprouting and development of new vasculature from the pre-existing blood vessels is termed as angiogenesis, or neovascularization. Endothelial cells, which line all blood vessels, are mainly involved in angiogenesis. Inhibition of angiogenesis has been shown to suppress tumor growth. Hence, currently the use of anti-angiogenic agents in cancer is under intensive investigation. Few in vivo assay models, including the Matrigel plug assay, chick chorioallantoic membrane (CAM) assay, and the corneal angiogenesis assay, have been developed that allow accurate evaluation of angiogenic response. Endothelial tube formation assay is one among the most extensively used in vitro assays to model the reorganization stage of angiogenesis and to test angiogenesis inhibitors. The rat aortic ring assay links the gap between in vitro and in vivo models. This explant organ culture system model of angiogenesis is based on the capacity of activated endothelial cells to invade three-dimensional (3D) substrates.
