Patient-derived mini-colons enable long-term modeling of tumor-microenvironment complexity

The compromise to reduce, replace, and refine (3Rs) animal usage in cancer research demands the development of biologically capable ex vivo cancer models. The establishment of three-dimensional organoid-based systems has paved the way in this direction by bringing some realistic in vivo features to the in vitro context. However, faithful modeling of cancer requires a degree of tissue-level organization, multi-cellular diversity, biological durability, and experimental flexibility that far exceeds the capabilities of any existing in vitro systems. Here we implemented tissue engineering and microfabrication technologies to develop topobiologically complex patient-specific avatars of colorectal cancer able to overcome those limitations. These miniature tissues consist of long-lived gut-like-shaped healthy colon epithelia (“mini-colons”) that allow the stable integration of cancer cells and their native tumor microenvironment on a platform designed for the real-time high-resolution evaluation of cellular dynamics. This provides an unprecedented repertoire of ex vivo experimental possibilities, which we illustrate through different applications, including the discovery of a cancer associated fibroblast-triggered mechanism driving colorectal cancer invasion. As a whole, our mini-colon system pushes the boundaries of ex vivo cancer research in both basic and pre-clinical settings.