Department of Chemical and Biomolecular Engineering, Johns Hopkins Physical Sciences-Oncology Center, Johns Hopkins University, Baltimore, MD 21218, USA.
Am J Physiol Cell Physiol. 2012 Apr 15;302(8):C1243-56. doi: 10.1152/ajpcell.00011.2012. Epub 2012 Jan 25.
The extracellular matrix (ECM), important for maintaining tissue homeostasis, is abnormally expressed in mammary tumors and additionally plays a crucial role in angiogenesis. We hypothesize that breast cancer cells (BCCs) deposit ECM that supports unique patterns of vascular morphogenesis of endothelial cells (ECs). Evaluation of ECM expression revealed that a nontumorigenic cell line (MCF10A), a tumorigenic cell line (MCF7), and a metastatic cell line (MDA-MB-231) express collagens I and IV, fibronectin, and laminin, with tenascin-C limited to MCF10A and MCF7. The amount of ECM deposited by BCCs was found to be higher in MCF10A compared with MCF7 and MDA231, with all ECM differing in their gross structure but similar in mean fiber diameter. Nonetheless, deposition of ECM from BCC lines was overall difficult to detect and insufficient to support capillary-like structure (CLS) formation of ECs. Therefore, a coculture approach was undertaken in which individual BCC lines were cocultured with fibroblasts. Variation in abundance of deposited ECM, deposition of ECM proteins, such as absent collagen I deposition from MDA231-fibroblast cocultures, and fibril organization was found. Deposited ECM from fibroblasts and each coculture supported rapid CLS formation of ECs. Evaluation of capillary properties revealed that CLS grown on ECM deposited from MDA231-fibroblast cocultures possessed significantly larger lumen diameters, occupied the greatest percentage of area, expressed the highest levels of von Willebrand factor, and expressed the greatest amount of E-selectin, which was upregulated independent of exposure to TNF-α. To our knowledge, this is the first study to report tumor cell ECM-mediated differences in vascular capillary features, and thus offers the framework for future investigations interrogating the role of the tumor ECM in supporting vascular morphogenesis.
细胞外基质（ECM）对于维持组织内稳态很重要，在乳腺肿瘤中异常表达，此外还在血管生成中发挥关键作用。我们假设乳腺癌细胞（BCC）沉积 ECM，支持内皮细胞（EC）独特的血管形态发生模式。对 ECM 表达的评估表明，非致瘤细胞系（MCF10A）、致瘤细胞系（MCF7）和转移细胞系（MDA-MB-231）表达胶原 I 和 IV、纤维连接蛋白和层粘连蛋白，而 tenascin-C 仅局限于 MCF10A 和 MCF7。发现 BCC 沉积的 ECM 量在 MCF10A 中比 MCF7 和 MDA231 更高，所有 ECM 在大体结构上有所不同，但平均纤维直径相似。尽管如此，BCC 系沉积的 ECM 总体上难以检测，并且不足以支持 EC 的毛细血管样结构（CLS）形成。因此，采用共培养方法，将单个 BCC 系与成纤维细胞共培养。发现沉积 ECM 的丰度存在差异，例如 MDA231-成纤维细胞共培养中缺失胶原 I 沉积，以及纤维组织的排列存在差异。成纤维细胞和每种共培养物沉积的 ECM 均支持 EC 的快速 CLS 形成。对毛细血管特性的评估表明，在 MDA231-成纤维细胞共培养物沉积的 ECM 上生长的 CLS 具有明显更大的管腔直径，占据最大的面积百分比，表达最高水平的血管性血友病因子，并表达最高量的 E-选择素，其上调与 TNF-α 暴露无关。据我们所知，这是第一项报道肿瘤细胞 ECM 介导的血管毛细血管特征差异的研究，为未来研究肿瘤 ECM 在支持血管形态发生中的作用提供了框架。
