Expression and activity determination of human angiostatin (k1-3) in culture cells and larvae of silkworm.

Angiostatin (k1-3) gene was inserted into Bombyx mori baculovirus transfer vector pBacPAK8 and cotransfected with lineared DNA of Bm-BacPAK6 virus into BmN cells. The homologous recombination occurred inside the cells, and the recombinant virus BacPAK-angiostatin was expressed, as identified by DNA dot blotting. The BmN cells and fifth instars were infected by the recombinant virus BacPAK-angiostatin; expression product was run in the SDS-PAGE, and its immunoreactivity was determined by using ELISA and Western blotting. The bio-activity of the protein product was determined by using human umbilical vein endothelial cells ( ECV304 ) proliferation test in vitro and by using CAM vascular inhibition test in vivo. The expression activity achieved the highest point at the 72nd hour in BmN cells (22 u / 2x10(6) cells) and at 144th hour in larvae (159 u/ml). At the concentration of 2.5 u/ml, angiostatin induced apoptosis of endothelial cells in 24 h and also inhibited angiogenesis in CAM.