Vitronectin improves cell survival after radiation injury in human umbilical vein endothelial cells.

Vitronectin (VN) is a multi-functional protein involved in extracellular matrix (ECM)-cell binding through integrin receptors on the cell surface, which is an important environmental process for maintaining biological homeostasis. We investigated how VN affects the survival of endothelial cells after radiation damage. VN attenuated radiation-induced expression of p21, an inhibitor of cell cycle progression, and selectively inhibited Erk- and p38 MAPK-dependent p21 induction after radiation exposure through regulation of the activity of GSK-3ß. VN also reduced the cleavage of caspase-3, thereby inhibiting radiation-induced apoptotic cell death. These results suggest that VN has important roles in cell survival after radiation damage.