Biomedical Engineering Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea.
Department of Biomedical engineering, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Biotechnol Bioeng. 2019 Nov;116(11):3041-3052. doi: 10.1002/bit.27114. Epub 2019 Jul 26.
The purpose of this study was to demonstrate self-organizing in vitro multicellular tumor spheroid (MCTS) formation in a microfluidic system and to observe the behavior of MCTSs under controlled microenvironment. The employed microfluidic system was designed for simple and effective formation of MCTSs by generating nutrient and oxygen gradients. The MCTSs were composed of cancer cells, vascular endothelial cells, and type I collagen matrix to mimic the in vivo tumor microenvironment (TME). Cell culture medium was perfused to the microfluidic device loaded with MCTSs by a passive fluidic pump at a constant flow rate. The dose response to an MMPs inhibitor was investigated to demonstrate the effects of biochemical substances. The result of long-term stability of MCTSs revealed that continuous perfusion of cell culture medium is one of the major factors for the successful MCTS formation. A continuous flow of cell culture medium in the in vitro TME greatly affected both the proliferation of cancer cells in the micro-wells and the sustainability of the endothelial cell-layer integrity in the lumen of microfluidic channels. Addition of MMP inhibitor to the cell culture medium improved the stability of the collagen matrix by preventing the detachment and shrinkage of the collagen matrix surrounding the MCTSs. In summary, the present constant flow assisted microfluidic system is highly advantageous for long-term observation of the MCTS generation, tumorous tissue formation process and drug responses. MCTS formation in a microfluidic system may serve as a potent tool for studying drug screening, tumorigenesis and metastasis.
本研究旨在展示在微流控系统中自组织体外多细胞肿瘤球体（MCTS）的形成，并观察 MCTS 在受控微环境下的行为。所采用的微流控系统旨在通过生成营养和氧气梯度来简单有效地形成 MCTS。MCTS 由癌细胞、血管内皮细胞和 I 型胶原基质组成，以模拟体内肿瘤微环境（TME）。细胞培养液通过被动流体泵以恒定流速灌注到加载有 MCTS 的微流控装置中。研究了 MMPs 抑制剂的剂量反应，以证明生化物质的作用。MCTS 长期稳定性的结果表明，细胞培养液的连续灌注是成功形成 MCTS 的主要因素之一。在体外 TME 中细胞培养液的连续流动极大地影响了微井中癌细胞的增殖和内皮细胞层在微通道腔中的完整性的可持续性。向细胞培养液中添加 MMP 抑制剂通过防止围绕 MCTS 的胶原基质的脱离和收缩来提高胶原基质的稳定性。总之，本持续流动辅助微流控系统非常有利于长期观察 MCTS 的生成、肿瘤组织形成过程和药物反应。微流控系统中的 MCTS 形成可能成为研究药物筛选、肿瘤发生和转移的有力工具。
