Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Integrative Biosciences, University of Brain Education, Cheonan 31228, Republic of Korea.
School of Mechanical Engineering, Korea University, Seoul 02841, Republic of Korea.
Acta Biomater. 2018 Aug;76:146-153. doi: 10.1016/j.actbio.2018.07.001. Epub 2018 Jul 4.
Cancer-associated fibroblasts (CAFs) play a pivotal role in tumor growth, but very little has been known about its characteristics and origin. Recently, cancer-derived exosome has been suggested to transdifferentiate CAFs, by a new mechanism of endothelial to mesenchymal transition (EndMT), initiating angiogenic processes and triggering metastatic evolution. However, an enabling tool in vitro is yet to be developed to investigate complicated procedures of the EndMT and the transdifferentiation under reconstituted tumor microenvironment. Here we proposed an in vitro microfluidic model which enables to monitor a synergetic effect of complex tumor microenvironment in situ, including extracellular matrix (ECM), interstitial flow and environmental exosomes. The number of CAFs differentiated from human umbilical vein endothelial cells (HUVECs) increased with melanoma-derived exosomes, presenting apparent morphological and molecular changes with pronounced motility. Mesenchymal stem cell (MSC)-derived exosomes were found to suppress EndMT, induce angiogenesis and maintain vascular homeostasis, while cancer-derived exosomes promoted EndMT. Capabilities of the new microfluidic model exist in precise regulation of the complex tumor microenvironment and therefore successful reconstitution of 3D microvasculature niches, enabling in situ investigation of EndMT procedure between various cell types.
This study presents an in vitro 3D EndMT model to understand the progress of the CAF generation by recapitulating the 3D tumor microenvironment in a microfluidic device. Both cancer-derived exosomes and interstitial fluid flow synergetically played a pivotal role in the EndMT and consequent formation of CAFs through a collagen-based ECM. Our approach also enabled the demonstration of a homeostatic capability of MSC-derived exosomes, ultimately leading to the recovery of CAFs back to endothelial cells. The in vitro 3D EndMT model can serve as a powerful tool to validate exosomal components that could be further developed to anti-cancer drugs.
癌症相关成纤维细胞（CAFs）在肿瘤生长中起着关键作用，但人们对其特征和来源知之甚少。最近，有人提出，癌症衍生的外泌体通过内皮到间充质转化（EndMT）的新机制，使 CAFs 发生转分化，从而启动血管生成过程并引发转移演变。然而，目前还没有开发出体外的有效工具来研究复杂的 EndMT 过程和在重建的肿瘤微环境中的转分化。在这里，我们提出了一种体外微流控模型，该模型能够原位监测复杂肿瘤微环境的协同作用，包括细胞外基质（ECM）、间质流和环境外泌体。黑色素瘤衍生的外泌体使来自人脐静脉内皮细胞（HUVEC）的 CAFs 数量增加，呈现出明显的形态和分子变化，表现出明显的运动性。间充质干细胞（MSC）衍生的外泌体被发现可抑制 EndMT，诱导血管生成并维持血管稳态，而癌症衍生的外泌体则促进 EndMT。新的微流控模型的能力在于对复杂肿瘤微环境进行精确调节，因此能够成功重建 3D 微血管龛，从而原位研究各种细胞类型之间的 EndMT 过程。
本研究提出了一种体外 3D EndMT 模型，通过在微流控装置中重建 3D 肿瘤微环境来理解 CAF 生成的过程。癌症衍生的外泌体和间质液流通过基于胶原蛋白的 ECM 协同作用，在 EndMT 和随后 CAFs 的形成中发挥关键作用。我们的方法还证明了 MSC 衍生的外泌体的稳态能力，最终导致 CAFs 恢复为内皮细胞。体外 3D EndMT 模型可作为验证外泌体成分的有力工具，这些成分可进一步开发为抗癌药物。
