Study on cloning, expression and biological activity of vascular endothelial cell growth inhibitor: endostatin

Objective: To investigate the biological activity of recombinant vascular endothelial growth inhibitor, endostatin from Chinese fetus hepatocytes. Methods: Endostatin was expressed in E.coli with pBV220 expression vector and purified with heparin Sepharose CL 6B and Sephacryl S 200. The biological activity of endostatin was detected with endothelial cells proliferation test in vitro and CAM vascular inhibition test. Results: The expression rate of endostatin in recombinant E.coli was 28.5% and its purity reached 90.5% after purification. Purified endostatin showed significant inhibitory effect on endothelial cells, which IC 50 was 72 μg/ml. At the concentration of 20 μg/ml, endostatin induced apoptosis of endothelial cells within 48 h. Endostatin also inhibited angiogenesis in CAM. At the concentration of 200 μg/ml, the vascular index was degraded by 30%. Conclusion: The results suggest that endostatin is an effective inhibitor of endothelial cells and has potential therapeutic usage on angiogenic disease and cancer.