Thrombospondin modulates basic fibroblast growth factor activities on endothelial cells.

We previously reported that thrombospondin (TSP) induces endothelial cell (EC) adhesion, spreading and motility, suggesting that it can play a role in angiogenesis. We then studied whether TSP might modulate EC response to known angiogenic stimuli in vitro. Here we describe that TSP inhibits EC chemotactic response to basic fibroblast growth factor (bFGF). Furthermore, TSP and its 140 kD fragment reduce EC proliferative response to serum and bFGF. These data support the indicated role of TSP and its 140 kD fragment in angiogenesis and in related pathologies including tumor malignancy.