Synstatin is a peptide derived from amino acids 92-119 of the mouse syndecan sequence and is the active site for the alphavbeta3 and alphavbeta5 integrin activation mechanism. Syndecan is a critical regulator of these two integrins during angiogenesis and tumourigenesis, and this activation process can be blocked by the synstatin peptide. Synstatin displays an IC50 of 100-300 nM when used in vitro to inhibit alphavbeta3 dependent adhesion and cell migration on vitronectin or in aortic ring angiogenesis assays. Synstatin is a potent inhibitor of angiogenesis in vivo and blocks alphavbeta3 mediated tumour cell adhesion and migration and tumour formation in mouse models.
