You are working with a neuronal cell line isolated from a human brain tumor. It appears to have a neuronal phenotype when grown in culture on laminin coated dishes but appears to have more of a typical round, small (3 to 5mm) phenotype when grown on a standard, collagen-only coated dish or a poly-lysine coated (positive charge only – no ECM component) dish. Under all 3 cases the cells attach to the substrate. You suspect that the reason the neuronal phenotype is supported by the laminin coating is due to the ability of laminin, but not collagen or poly-lysine, to bind to the integrin receptors RGD binding domain thus triggering a molecular cascade that generates the neuronal phenotype. How might you test this hypothesis?