Ex Vivo Assay for Organ-Specific Cancer Cell Invasion

Metastasis is the leading cause of cancer-related mortality, yet experimental models inadequately recapitulate the tissue-specific microenvironments that shape metastatic dissemination. In vivo systems provide physiological relevance but are poorly suited for mechanistic studies and screening, whereas conventional in vitro assays lack the organ-specific extracellular matrix (ECM) context that critically influences invasive behavior. To address this gap, an ex vivo method is established that balances biological relevance with scalability, affordability, and ease of use. Mild detergent decellularization of mouse organs followed by vibratome slicing generates optically transparent lung, liver, and intestine scaffolds that preserve native ECM architecture, mechanics, and composition. These organ-derived matrices are readily integrated into standard microfluidic channels and analyzed using conventional fluorescence microscopy, enabling quantitative assessment of cancer cell invasion without specialized infrastructure. Benchmarking with breast cancer cell lines of well-defined invasive capacity confirms the robustness and biological relevance of the platform. Non-invasive MCF7 cells fail to infiltrate any scaffold, whereas highly invasive MDA-MB-231 cells display organ-specific invasion, preferentially penetrating lung and liver ECM while showing virtually no invasion of intestinal scaffolds, consistent with clinically observed metastatic tropism. Quantitative invasion rates closely match values reported in vivo by intravital microscopy. Overall, this ex vivo system provides an accessible and scalable platform to study ECM-driven determinants of metastatic invasion while reducing reliance on animal models.