Signatures of tissue surface tension in 3D models with two tissue types

Dense biological tissues maintain sharp surfaces between cell types performing different roles. For example, in multi-layered epithelia, the bottom-most basal layer remains distinctly compartmentalized from the supra-basal layer above, in spite of newly born basal cells being pushed upwards. Similarly, in experimental co-cultures of healthy (MCF10A) and invasive (MDA-MB-231) breast cell lines, initially MCF10A forms a distinct inner core leaving the MDA231 exposed, although that structure inverts on longer timescales. To better understand the mechanisms for such sharp compartmentalization, we study the effect of an imposed heterotypic tension at the interface between two distinct cell types in a fully 3D model for confluent tissues. We find that cells rapidly sort to generate a tissue-scale interface between cell types, and cells adjacent to this interface exhibit signature geometric features including nematic-like ordering and bimodal facet areas along the surface. The magnitude of these features scale directly with the magnitude of imposed tension, suggesting that experiments might estimate the magnitude of tissue surface tension simply by segmenting a 3D tissue.