Resolving cancer–stroma interfacial signalling and interventions with micropatterned tumour–stromal assays

Tumour–stromal interactions are a determining factor in cancer progression. In vivo, the interaction interface is associated with spatially resolved distributions of cancer and stromal phenotypes. Here, we establish a micropatterned tumour–stromal assay (μTSA) with laser capture microdissection to control the location of co-cultured cells and analyse bulk and interfacial tumour–stromal signalling in driving cancer progression. μTSA reveals a spatial distribution of phenotypes in concordance with human oestrogen receptor-positive (ER+) breast cancer samples, and heterogeneous drug activity relative to the tumour–stroma interface. Specifically, an unknown mechanism of reversine is shown in targeting tumour–stromal interfacial interactions using ER+ MCF-7 breast cancer and bone marrow-derived stromal cells. Reversine suppresses MCF-7 tumour growth and bone metastasis in vivo by reducing tumour stromalization including collagen deposition and recruitment of activated stromal cells. This study advocates μTSA as a platform for studying tumour microenvironmental interactions and cancer field effects with applications in drug discovery and development.