1 Tissue Repair Laboratory, Department of Bioengineering, National University of Singapore , Singapore, Singapore .
Tissue Eng Part A. 2014 Jun;20(11-12):1758-66. doi: 10.1089/ten.TEA.2013.0245. Epub 2014 Apr 30.
The induction of angiogenesis and the promotion of tumor growth and invasiveness are processes critical to metastasis, and are dependent on reciprocal interactions between tumor cells and their microenvironment. The formation of a clinically relevant tumor requires support from the surrounding stroma, and it is hypothesized that three-dimensional (3D) tumor coculture models offer a microenvironment that more closely resembles the physiological tumor microenvironment. In this study, we investigated the effects of tissue-engineered 3D architecture and tumor-stroma interaction on the angiogenic factor secretion profiles of U2OS osteosarcoma cells by coculturing the tumor cells with immortalized fibroblasts or human umbilical vein endothelial cells (HUVECs). We also carried out Transwell migration assays for U2OS cells grown in monoculture or fibroblast coculture systems to study the physiological effect of upregulated angiogenic factors on endothelial cell migration. Anti-IL-8 and anti-vascular endothelial growth factor (VEGF)-A therapies were tested out on these models to investigate the role of 3D culture and the coculture of tumor cells with immortalized fibroblasts on the efficacy of antiangiogenic treatments. The coculture of U2OS cells with immortalized fibroblasts led to the upregulation of IL-8 and VEGF-A, especially in 3D culture. Conversely, coculture with endothelial cells resulted in the downregulation of VEGF-A for cells seeded in 3D scaffolds. The migration of HUVECs through the Transwell polycarbonate inserts increased for the 3D and immortalized fibroblast coculture models, and the targeted inhibition of IL-8 greatly reduced HUVEC migration despite the presence of VEGF-A. A similar effect was not observed when anti-VEGF-A neutralizing antibody was used instead, suggesting that IL-8 plays a more critical role in endothelial cell migration than VEGF-A, with significant implications on the clinical utility of antiangiogenic therapy targeting VEGF-A.
血管生成的诱导以及肿瘤生长和侵袭的促进是转移过程中的关键步骤，这依赖于肿瘤细胞与其微环境之间的相互作用。一个具有临床相关性的肿瘤的形成需要周围基质的支持，并且人们假设三维（3D）肿瘤共培养模型提供了更接近生理肿瘤微环境的微环境。在这项研究中，我们通过将肿瘤细胞与永生化成纤维细胞或人脐静脉内皮细胞（HUVEC）共培养，研究了组织工程 3D 结构和肿瘤-基质相互作用对 U2OS 骨肉瘤细胞分泌血管生成因子谱的影响。我们还进行了 U2OS 细胞在单核培养或成纤维细胞共培养系统中生长的 Transwell 迁移实验，以研究上调的血管生成因子对内皮细胞迁移的生理影响。我们在这些模型上测试了抗 IL-8 和抗血管内皮生长因子（VEGF）-A 治疗，以研究 3D 培养和肿瘤细胞与永生化成纤维细胞共培养对抗血管生成治疗效果的作用。U2OS 细胞与永生化成纤维细胞共培养会导致 IL-8 和 VEGF-A 的上调，尤其是在 3D 培养中。相反，与内皮细胞共培养会导致 3D 支架中接种的细胞下调 VEGF-A。穿过 Transwell 聚碳酸酯插入物的 HUVEC 迁移增加，对于 3D 和永生化成纤维细胞共培养模型，靶向抑制 IL-8 会大大降低 HUVEC 迁移，尽管存在 VEGF-A。当使用抗 VEGF-A 中和抗体代替时，并未观察到类似的效果，这表明 IL-8 在内皮细胞迁移中的作用比 VEGF-A 更为关键，这对靶向 VEGF-A 的抗血管生成治疗的临床应用具有重要意义。
