How cancer cells and their anchorage-dependent normal counterparts respond to the adhesion ligand density and stiffness of the same extracellular matrix (ECM) is still not very clear. Here we investigated the effects of ECM adhesion ligand density and stiffness on bone tumor cells (osteosarcoma cells) and bone forming cells (osteoblasts) by using poly (ethylene glycol) diacrylate (PEGDA) and methacrylated gelatin (GelMA) hydrogels. By independently changing the PEGDA and GelMA content in the hydrogels, we achieved crosslinked hydrogel matrix with independently tunable stiffness (1.6, 6 and 25 kPa for 5%, 10%, 15% PEDGA, respectively) and adhesion ligand density (low, medium and high for 0.05%, 0.2%, 0.5% GelMA respectively). By using a series of biochemical and cell biological characterizations as well as in vivo studies, we confirmed that osteosarcoma and osteoblastic cells responded differently to the stiffness and adhesion ligand density within 3D ECM. When cultured within the 3D PEGDA/GelMA hydrogel matrix, osteosarcoma cells are highly dependent on the matrix stiffness via regulating the integrin-mediated focal adhesion (FA) pathway, whereas osteoblasts are highly sensitive to the matrix adhesion ligand density through regulating the integrin-mediated adherens junction (AJ) pathway. However, when seeded on the 2D surface of the hydrogels, osteosarcoma cells behaved differently and became sensitive to the matrix adhesion ligand density because they were "forced" to attach to the substrate, similar to anchorage-dependent osteoblasts. This study might provide new insights into rational design of scaffolds for generating in vitro tumor models to test anticancer therapeutics and for regenerating tissue to repair defects.

中文翻译：

---

通过水凝胶解开骨肿瘤细胞和骨形成细胞对基质刚度和粘附配体密度的反应。

癌细胞及其依附锚定的正常对应物如何响应同一细胞外基质（ECM）的粘附配体密度和刚度仍不清楚。在这里，我们通过使用聚（乙二醇）二丙烯酸酯（PEGDA）和甲基丙烯酸明胶（GelMA）水凝胶研究了ECM粘附配体密度和硬度对骨肿瘤细胞（骨肉瘤细胞）和骨形成细胞（成骨细胞）的影响。通过独立改变水凝胶中的PEGDA和GelMA含量，我们获得了具有独立可调的刚度（分别为5％，10％，15％PEDGA，分别为1.6、6和25 kPa）和粘合配体密度（低，中和高）的交联水凝胶基质。高分别为0.05％，0.2％和0.5％的GelMA）。通过使用一系列生化和细胞生物学特性以及体内研究，我们证实，骨肉瘤和成骨细胞对3D ECM内的硬度和粘附配体密度的反应不同。当在3D PEGDA / GelMA水凝胶基质中培养时，骨肉瘤细胞通过调节整联蛋白介导的粘着斑（FA）途径高度依赖于基质刚度，而成骨细胞通过调节整联蛋白介导的对基质粘附配体密度高度敏感粘附连接（AJ）途径。但是，当植入水凝胶的2D表面时，骨肉瘤细胞的行为会有所不同，并且对基质粘附配体密度变得敏感，因为它们被“强迫”附着在基质上，类似于锚定依赖性成骨细胞。