Biophysical principles of cell competition and elimination

Cell competition is a highly conserved mechanism through which cells with lower fitness levels than surrounding cells are actively removed from tissues. Differences in fitness may result from intrinsic tissue heterogeneity or be caused by differentiation, infections, or mutations. The resulting competition dynamics act as a key regulator of various biological processes during development and homeostasis. The underlying mechanical factors often remain unclear. Here, we discuss the biophysical principles of cell competition and elimination via extrusion or delamination. Recent advances have uncovered how fitness is determined by cellular mechanical properties, which can regulate winning or losing, and how cells use forces to outcompete each other. Furthermore, forces can influence the fate and direction of eliminated loser cells, which govern functional tissue development and disease progression.