IGF-I stimulates chemotaxis of human neuroblasts. Involvement of type 1 IGF receptor, IGF binding proteins, phosphatidylinositol-3 kinase pathway and plasmin system

SH-SY5Y human neuroblastoma cells express IGF receptors, IGFs and IGF binding proteins (IGFBPs), and provide a model for studying the role of the IGF system in human neuronal development. We investigated the effect of IGF-I and des(1-3)IGF-I on the motility of SH-SY5Y cells by a cell migration assay based on the assessment of the number of cells which migrated across 8 microm pore size membranes and around an agarose drop. IGF-I and des(1-3)IGF-I stimulated neuroblast chemotaxis in a dose-dependent manner. Treatment of cells with these agents for 24 h resulted in a significant increase (IGF-I by 70% and des(1-3)IGF-I by 90%; P