Hierarchical Collagen Nanofiber Gels Recapitulate a Physiologically Relevant Tumor Stromal Microenvironment.

Cancer tissue forms cancer stroma with a high elastic modulus due to increased type I collagen (Col I) production from fibroblasts and cross-linking of Col I fibers. Stiffened cancer stroma acts on cancer cells as a mechanical stress and promotes cancer progression. This highlights the need for culture scaffolds that recapitulate the structural, mechanical, and biological characteristics of the tumor stromal microenvironment. In this study, we attempted to create a scaffold material that mimics the fibrous structure and elastic modulus of in vivo cancer tissue using Col I. By gelation with collagen microfibers (CMFs) and collagen nanofibers (CNFs) at various concentrations, we were able to produce collagen gels with elastic moduli ranging from 1 to 18 kPa and 2 to 80 kPa, respectively. When cultured on CNF gels with a similar elasticity to in vivo colorectal cancer tissue, JC-011 exhibited proliferation comparable to that on Matrigel. Furthermore, JC-011 cells cultured on CNF gels exhibited cancer-related protein expression patterns highly similar to those observed on Matrigel. Together, these findings demonstrate that hierarchical CNF gels recapitulate a physiologically relevant tumor stromal microenvironment and provide a promising collagen-based platform for investigating cancer cell-matrix interactions.