αvβ3 Integrin Signaling Pathway Is Involved in Insulin-Like Growth Factor I-Stimulated Human Extravillous Trophoblast Cell Migration

IGF-I and -II provide paracrine and autocrine stimuli, respectively, for extravillous trophoblast (EVT) cell migration. This study examined the role of αvβ3 integrin and its signaling pathway in IGF-I-stimulated migration. Migration assays were conducted using cultured EVT cells treated with or without IGF-I in the presence or absence of αIR3, Arg-Gly-Asp (RGD) hexapeptide, and antibody against αvβ3 integrin. Morphological changes were studied using scanning electron microscopy. Colocalization of α5β1 αvβ3 integrins, vinculin, focal adhesion kinase, and paxillin were determined by immuno-cytochemistry and immunoblotting. The results showed that IGF-I could stimulate EVT cell migration in a time- and dose-dependent manner and addition of αIR3, Arg-Gly-Asp hexapeptide, and antibody against αvβ3 integrin attenuated the IGF-I migratory effect. Scanning electron microscopy images revealed that IGF-I promoted lamellipodia formation. Immunostaining and immunoblotting exhibited the colocalization of αvβ3 integrin...