Tumor endothelial cell targeted cyclic RGD-modified heparin derivative: Inhibition of angiogenesis and tumor growth

Purpose. We prepared tumor endothelium targeted cRGD-modified heparin derivative (cRGD-HL) by coupling heparin-lithocholic acid (HL) with cRGDyK, and evaluated inhibition effects of cRGD-HL on angiogenesis and tumor growth. Methods. To evaluate antiangiogenic activity of cRGD-HL, we performed tests on endothelial cell adhesion and migration to vitronectin, tube formation, binding affinity to purified α_vβ₃ integrin, and in vivo Matrigel plug assay. The antitumor activity of cRGD-HL was also evaluated by monitoring tumor growth and microvessel formation in squamous cell carcinoma (SCC7) tumor. Results. The cRGD-HL significantly inhibited adhesion and migration of endothelial cells to vitronectin, and tubular structures of endothelial cells. Compared to cRGDyK and HL, cRGD-HL has high binding affinity to purified α_vβ₃ integrin. The enhanced antiangiogenic effect of cRGD-HL was confirmed in Matrigel assay by showing the significant inhibition of bFGF-driven angiogenesis and blood vessel formation. It was thought that potent antiangiogenic effect of cRGD-HL was probably due to the interference of α_vβ₃-mediated interaction, resulting in the enhanced antitumoral activity against SCC7 tumor. Conclusion. These results demonstrated that cRGD-modified heparin derivative enhanced anti-angiotherapeutic effects against solid tumor, and therefore, it could be applied to treat various cancers and angiogenic diseases as a potent angiogenesis inhibitor.