Recapitulating and Deciphering Tumor Microenvironment by Using 3D Printed Plastic Brick-Like Microfluidic Cell Patterning.

Within the body, tumor cells are surrounded by neighboring counterparts, such as extracellular matrix, vasculature, and host stroma, which is also known as the tumor microenvironment. To understand tumorigenesis, it is essential to reconstitute the incorporative tumor niche with quantitative measurements in vitro. Here, a 3D printed plastic brick-like microfluidic gadget is developed for spatially patterning tumors and fibroblasts, enabling the recapitulation of tumor microenvironment with minimized microfluidic expertise and compatibility of standard pipetting. This method facilitates heterotypic coculturing, quantitative phenotype decoding, and downstream molecular assays with a small number of cells (less than 100). Phenotypic and gene/protein expression-based analysis of cell-cell interactions between fibrosarcoma cells and fibroblasts on this device reveals that the tumor and its counterparts show reciprocal synergism mainly by upregulation of proinflammatory cytokines. Notably, at the whole transcriptional landscape (RNA-seq), fibroblasts display a transition from normal to cancer-associated fibroblast (CAF)-like phase, and tumor cells exhibit a hyperactive ribosome biogenesis. The mouse xenograft model is also involved to validate the in vitro analysis. Given its easy-to-use feature, full compatibility with molecular analysis, and open-source accessibility, this approach provides an in vitro experimental system to advance knowledge of tumorigenesis and the corresponding tumor microenvironment.