Proteolytic Remodeling of 3D Bioprinted Tumor Microenvironments

In native tissue, remodeling of the pericellular space is essential for cellular activities and is mediated by tightly regulated proteases. Protease activity is dysregulated in many diseases, including many forms of cancer. Increased proteolytic activity is directly linked to tumor invasion into stroma, metastasis, and angiogenesis as well as all other hallmarks of cancer. Here we show how integrated 3D bioprinted structures with distinctly different responses to proteolytic activity can be utilized for systematic investigation of proteolytic remodeling of the extra cellular matrix and the impact of stromal cells on protease driven processes. Bioprinted structures combining non-degradable and degradable hydrogels were designed and demonstrated to be selectively degraded by proteases allowing for protease-mediated material reorganization with high spatial resolution. Bioprinting of tumor microenvironments combining bioinks with different susceptibilities to proteolytic degradation shows that breast cancer cell proliferation, migration into stromal compartments, and spheroid size are significantly increased in protease degradable hydrogels, but only in the presence of fibroblasts. Proteolytic remodeling of the tumor microenvironment has a significant effect on tumor progression and is drastically influenced by the intimate crosstalk between fibroblast and breast cancer cells.