Optimization of recombinant human endostatin refolding / 基础医学与临床

Objective To optimize the conditions for enhancing the refolding of a novel recombinant human(rh)endostatin and test the biological activities of refolded endostatin.Methods The partial purified inclusion bodies of rh-endostatin were dissolved with 6 mol/L guanidine-HCl followed by combination of dilution and dialysis of the dissolved endostatin.The refolded endostatin was then purified by cation-exchange chromatography.The biological activities of purified rh-endostatin were assessed by endostatin-specific monoclonal antibody and chick embryo chorioallantoic membrane assay.Results A 46% refolding yield was achieved after optimizing the refolding conditions.The purified endostatin reacted with specific anti-endostatin monoclonal antibody and showed significant inhibition of angiogenesis in chick embryo ehorioallantoic membrane assay.Conclusion The method of highest refolding yield of human endostatin was developed.This optimized method significantly promotes the application of this novel human endostatin to preclinical and clinical studies.

Friend erythroleukemia cells induce angiogenesis in chick embryo chorioallantoic membrane and in human umbilical vein endothelial cells

The effects of Friend erythroleukemia cells on angiogenesis were studied in chick embryo chorioallantoic membrane assay and in human umbilical vein endothelial cells. In chorioallantoic membrane assay, the conditioned medium of Friend cells stimulated in vivo angiogenesis to an extent comparable to that observed with Prostaglandin El, used as positive control. Prostaglandin El added to conditioned medium of Friend cells did not further increase angiogenesis. Conditioned medium of Friend erythroleukemia cells also stimulated proliferation of human umbilical vein endothelial cells to an extent comparable to that observed with fetal bovine serum, used as positive control. Conditioned medium and fetal bovine serum together did not affect human umbilical vein endothelial cells proliferation, as compared to that observed when tested separately. These results seem to indicate that Friend erythroleukemia cells produce and secrete factors stimulating angiogenesis. These findings extend and confirm the hypothesis that successful angiogenesis is necessary for development of leukemias.