Cellular crowd control: overriding endogenous cell coordination makes cell migration more susceptible to external programming

As collective cell migration is essential in biological processes spanning development, healing, and cancer progression, methods to externally program cell migration are of great value. However, problems can arise if the external commands compete with strong, pre-existing collective behaviors in the tissue or system. We investigate this problem by applying a potent external migratory cue--electrical stimulation and electrotaxis--to primary mouse skin monolayers where we can tune cell-cell adhesion strength to modulate endogenous collectivity. Monolayers with high cell-cell adhesion showed strong natural coordination and resisted electrotactic control, with this conflict actively damaging the leading edge of the tissue. However, reducing pre-existing coordination in the tissue by specifically inhibiting E-cadherin-dependent cell-cell adhesion, either by disrupting the formation of cell-cell junctions with E-cadherin specific antibodies or rapidly dismantling E-cadherin junctions with calcium chelators, significantly improved controllability. Finally, we applied this paradigm of weakening existing coordination to improve control to demonstrate accelerated wound closure in vitro. These results are in keeping with those from diverse, non-cellular systems, and confirm that endogenous collectivity should be considered as a key, quantitative design variable when optimizing external control of collective migration.