Interactions between lung epithelium and interstitial fibroblasts are increasingly recognized as playing a major role in the progression of several lung pathologies, including cancer. Three-dimensional in vitro co-culture systems offer tissue-relevant platforms to study the signaling interplay between diseased and healthy cell types. Such systems provide a controlled environment in which to probe the mechanisms involved in epithelial-mesenchymal crosstalk. To recapitulate the native alveolar tissue architecture, we employed a cyst templating technique to culture alveolar epithelial cells on photodegradable microspheres and subsequently encapsulated the cell-laden spheres within poly (ethylene glycol) (PEG) hydrogels containing dispersed pulmonary fibroblasts. A fibroblast cell line (CCL-210) was co-cultured with either healthy mouse alveolar epithelial primary cells or a cancerous alveolar epithelial cell line (A549) to probe the influence of tumor-stromal interactions on proliferation, migration, and matrix remodeling. In 3D co-culture, cancerous epithelial cells and fibroblasts had higher proliferation rates. When examining fibroblast motility, the fibroblasts migrated faster when co-cultured with cancerous A549 cells. Finally, a fluorescent peptide reporter for matrix metalloproteinase (MMP) activity revealed increased MMP activity when A549s and fibroblasts were co-cultured. When MMP activity was inhibited or when cells were cultured in gels with a non-degradable crosslinker, fibroblast migration was dramatically suppressed, and the increase in cancer cell proliferation in co-culture was abrogated. Together, this evidence supports the idea that there is an exchange between the alveolar epithelium and surrounding fibroblasts during cancer progression that depends on MMP activity and points to potential signaling routes that merit further investigation to determine targets for cancer treatment.

人们日益认识到，肺上皮细胞与间质成纤维细胞之间的相互作用在包括癌症在内的几种肺部疾病的进展中起着重要作用。三维体外共培养系统提供组织相关平台，以研究患病和健康细胞类型之间的信号相互作用。这样的系统提供了可控制的环境，在其中可探究上皮-间充质串扰所涉及的机制。为了概括天然的肺泡组织结构，我们采用了一种囊肿模板技术在可光降解的微球上培养肺泡上皮细胞，随后将载有细胞的球囊封装在含有分散的肺成纤维细胞的聚（乙二醇）（PEG）水凝胶中。将成纤维细胞细胞系（CCL-210）与健康小鼠肺泡上皮原代细胞或癌性肺泡上皮细胞系（A549）共培养，以探讨肿瘤基质相互作用对增殖，迁移和基质重塑的影响。在3D共培养中，癌性上皮细胞和成纤维细胞具有更高的增殖率。当检查成纤维细胞的活力时，与癌性A549细胞共培养时，成纤维细胞迁移得更快。最后，用于基质金属蛋白酶（MMP）活性的荧光肽报告基因显示，当A549和成纤维细胞共同培养时，MMP活性增加。当MMP活性被抑制或当细胞在具有不可降解的交联剂的凝胶中培养时，成纤维细胞的迁移被显着抑制，并且共培养中癌细胞增殖的增加被消除。一起，