Since our studies use hydrogels coated with FN, an RGD-containing integrin ligand, the results we obtained are consistent with those in glioblastoma cells in that integrin-based signaling is likely supporting stiffness-dependent changes in spreading, stress fiber formation, focal adhesion assembly and cell cycling in CD44 KO fibroblasts despite the defect in motility. Here, FN1 is linked to glioblastoma.