Fig. 3
Hypothetical model for the role of integrin αvβ3 in angiogenesis. Angiogenic stimulus by basic fibroblast growth factor (bFGF) induces expression of αvβ3 and causes cells to invade the surrounding extracellular matrix (ECM) and to enter the cell cycle. When ligation of integrin αvβ3 is blocked, proliferating vascular cells undergo apoptosis, accompanied by an increase in p53 activity, p21WAF1/CIP1 expression, and a decrease in the Bcl2: Bax ratio. bFGF induces the activation of mitogen-activated protein kinase (MAPK) in vascular cells and leads to cell proliferation, differentiation, and migration.