Preparation, characterization and anti-angiogenesis activity of endostatin covalently modified by polysulfated...

To improve the stability and anti-angiogenesis activity of endostatin (ES), ES was modified by polysulfated heparin (PSH). SDS-PAGE and free amino group determination were employed to study purity and modification procedure. The inhibition of ES and PSH-ES on endothelial cell proliferation, chorioallantoic membrane (CAM) angiogenesis and choroidal neovascularization (CNV) were studied. Western blotting was employed to study the effects on the expression of vascular endothelial growth factor (VEGF) and pigment epithelium derived factor (PEDF). Changes of the secondary structure were analyzed by circular dichroism (CD) spectra and heat stability was also studied. Our study indicated that the modified product had a better heat tolerance than ES and its anti-angiogenesis activity in CAM model and CNV model were better than that of ES. More obvious down-regulation of VEGF and up-regulation of PEDF effects of PSH-ES than ES in chorioid tissues were detected. The result of CD analysis suggested that little secondary structure change was detected compared with that of ES. Compared with native ES, PSH-ES is a potential anti-tumor drug with better heat stability and better anti-angiogenesis activity both in CAM and CNV models.