A human organotypic microfluidic tumor model permits investigation of the interplay between patient-derived fibroblasts and breast cancer cells

Tumor-stroma interactions significantly influence cancer cell metastasis and disease progression. These interactions partly comprise crosstalk between tumor and stromal fibroblasts, but the key molecular mechanisms within the crosstalk that govern cancer invasion are still unclear. Here we adapted our previously developed microfluidic device as a 3D in vitro organotypic model to mechanistically study tumor-stroma interactions by mimicking the spatial organization of the tumor microenvironment on a chip. We co-cultured breast cancer and patient-derived fibroblast cells in 3D tumor and stroma regions, respectively, and combined functional assessments, including cancer cell migration, with transcriptome profiling to unveil the molecular influence of tumor-stroma crosstalk on invasion. This led to the observation that cancer-associated fibroblasts (CAF) enhanced invasion in 3D by inducing expression of a novel gene of interest, GPNMB, in breast cancer cells, resulting in increased migration speed. Importantly, knockdown of GPNMB blunted the influence of CAF on enhanced cancer invasion. Overall, these results demonstrate the ability of our model to recapitulate patient-specific tumor microenvironments to investigate the cellular and molecular consequences of tumor-stroma interactions.