Role of morphological differences in cell sorting*

Cell sorting (the spatial segregation of different cell types in a tissue or co-culture) is thought to play a vital role in development and disease. Although sorting in particle-model simulations is well studied, recent discoveries suggest that in confluent tissues (with no gaps or overlaps between cells), both fluid-solid transitions and surface tension are strongly influenced by cell shapes and topologies. Hence, we seek to analyze the behavior of cell sorting in a confluent model of tissues across the fluid-solid transition, and compare to experimental data for a 2D co-culture of breast carcinoma and non-malignant cell lines, which display robust sorting. Using a 2D Self-Propelled Voronoi (SPV) model, we investigate the role of disparity in cell shape and size in cell sorting for bidisperse mixtures. Quite surprisingly, we find very minimal segregation when cell shapes differ, but robust sorting when cell areas differ. This is consistent with experimental results, where carcinoma cells that are larger, more elongated and more motile robustly sort from non-cancerous cells in co-cultures. We will conclude by discussing possible mechanisms for size-based segregation.