Endostatin, a carboxyl-terminal fragment of collagen XVIII, has been shown to regress
tumors in mice. In this study, we have analyzed the mechanism of endostatin action on
endothelial cells and nonendothelial cells. Endostatin treatment of cow pulmonary artery
endothelial cells caused apoptosis, as demonstrated by three methods, annexin V-
fluorescein isothiocyanate staining, caspase 3, and terminal deoxynucleotidyl transferase-
mediated dUTP nick-end-labeling assay. Moreover, addition of endostatin led to a marked …