Impact of Hydrogel Elasticity and Adherence on Osteosarcoma Cells and Osteoblasts

Biochemical and physical properties of extracellular matrix (ECM) control cell behaviors, but how they affect osteosarcoma cells that do not require attachment and their normal counterparts (osteoblasts) that are anchorage-dependent has not been reported yet. In this study, the effects of matrix elasticity and adherence on osteosarcoma MG63 cells are investigated using four types of scaffolds (collagen type I, matrigel, alginate, and agarose) with varied adhesion ligands and rigidity, as compared with osteoblast hFOB1.19 cells. MG63 cells on 2D films are sensitive to ECM adherence, similar to the situation of hFOB1.19 cultured in both 2D and 3D. However, osteosarcoma cells in 3D hydrogels are sensitive to ECM elasticity rather than adherence, with tumor proliferation and malignancy varied with matrix rigidity. The results indicate that osteosarcomas cells might adopt unnatural characteristics on flat surfaces. But in 3D culture, they recover their normal state independent of adherence, as regulated mainly by ECM elasticity via the integrin-mediated focal adhesion pathway, which is further confirmed by in vivo studies. In contrast, osteoblasts and 2D cultured osteosarcoma cells are predominantly influenced by ECM bioactivity regulated by integrin-mediated adherens junction pathway. This study might provide new insights into rational design of scaffolds for tumor/tissue engineering.