Impact of Hydrogel Elasticity and Adherence on Osteosarcoma Cells and Osteoblasts

Abstract

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.

Proteinaceous Hydrogels for Bioengineering Advanced 3D Tumor Models

“…Col I hydrogels can be obtained by neutralizing the pH of the acid collagen solution and incubating at 37 °C, a crosslinking mechanism that is highly compatible with cell encapsulation. Col I can be used as a standalone 3D hydrogel for tumor models establishment, or be combined with other biomaterials to generate multifunctional hydrogels with improved ECM‐mimetic properties that can be valuable for in vitro modeling of a number of cancers including breast cancer, [ 44,138–144 ] colorectal cancer, [ 145,146 ] glioblastoma multiform (GBM), [ 124,147,148 ] liver, [ 149–151 ] lung cancer, [ 111,152,153 ] osteosarcoma [ 154,155 ] or ovarian cancer, [ 156 ] among others. Col I hydrogel stiffness can be easily manipulated by tuning the hydrogel precursor solution concentration, covalent crosslinking density and the chemical moieties involved in this crosslink.…”

“…In fundamental cancer research, Col I has been widely used to study mechanobiology and the effect of stiffness and porosity, in the tumorigenesis and invasion behavior of malignant cells. [ 111,140,141,154,159 ] It is well known that cancer cells can sense their ECM‐mimetic subtract stiffness, changing their phenotype and proliferation as a response. [ 160 ] Compression forces induced by interstitial fluid pressurization or by tumor growth have shown their importance in tumor progression due to mechanotransduction.…”

“…Col I hydrogels have also been recently explored for engineering biomimetic in vitro bone tissues for evaluating breast‐to‐bone metastasis [ 169 ] or osteosarcoma. [ 154,170 ] Hydrogel platforms were used to compare the effect of the stiffness and adherent molecules in osteosarcoma osteogenesis and tumorigenesis, using four types of hydrogels Col I (3.4 MPa), Matrigel (0.7 MPa), agarose (3.0 MPa), and alginate (0.6 MPa) (Figure 3f–j). All hydrogels supported osteoblasts (hFOB1.19) and osteosarcoma cells (MG‐63) proliferation.…”

“…Osteoblasts showed a higher osteogenic differentiation in Matrigel and collagen, indicating that cells‐ECM adhesion cues are crucial for their functionality and bioactivity. [ 154 ]…”

Understanding and Modeling Metastasis Biology to Improve Therapeutic Strategies for Combating Osteosarcoma Progression

“…Increasing sophistication of hydrogel-based models can be achieved through a combination of chemical engineering and biologic layering, including the construction of soluble mediator (growth factors, chemokines, peptidyl signaling molecules) gradients or combinatorial co-culturing of cancer cells with stromal cells including endothelial cells, fibroblasts, and immune cells. While hydrogels have been explored as a controlled drug release scaffold strategies for OS therapy (156)(157)(158), the study 3D scaffold tumor models for unraveling OS biology and metastasis remains limited, with some investigations describing differences in behavioral phenotype of malignant OS cells compared to non-transformed osteoblasts based upon matrix rigidity and elasticity (159,160). In addition to hydrogel scaffolds, chitosan, silk, and synthetic polymers have served as adhesive constructs for 3D OS modeling and have illuminated mechanisms behind viral permissiveness (161), hypoxia-induced angiogenic mediator secretions (162), drug resistance (163), and maintenance of stem cell phenotype (164).…”