Soluble VEGF receptors.
The three human VEGF receptors 1-3 mediate biological signals important for new blood vessel formation and lymphangiogenesis. Soluble VEGF receptors contain all the information necessary for high affinity ligand binding and have been used as experimental tools and regulators in several angiogenic in vitro and in vivo models. Recombinant receptor molecules can be used for specific inhibition of VEGF mediated signal transduction and for blocking tumor angiogenesis by limiting the amount of VEGF secreted from tumor cells or stroma cells. A naturally occurring soluble VEGFR-1 has been discovered in the supernatant from endothelial cells and at present appears to be the key regulator for the availability of VEGF secreted from different cells and tissues. The exact physiological role has not yet been demonstrated.