Neighbor-enhanced diffusivity in dense, cohesive cell populations.

Cell movement within dense tissues remains poorly understood. While contact inhibition of locomotion is a known phenomenon, it contradicts how cells disperse in tightly packed environments. Researchers have long sought to explain how cells overcome this constraint. Prior studies have focused on isolated cells or loosely connected groups. However, little is known about how adhesion affects movement in cohesive clusters. This gap motivated the need to explore the role of adhesion in collective cell behavior. The study of MDA-MB-231 cells offers a model for understanding tumor cell dynamics. No prior work had resolved how adhesion and propulsion interact to influence dispersal. This work aims to clarify how these forces contribute to cell mixing.

This study investigates how cell-cell adhesion influences the dispersal of densely packed cell populations. The specific problem is how cells move and mix despite physical constraints. The motivation stems from the need to understand tumor metastasis and tissue morphogenesis. The researchers aimed to test whether adhesion can enhance cell movement. They focused on MDA-MB-231 cells, a model for aggressive tumor behavior. The study examines different clustering modes to isolate effects of adhesion. The goal is to determine how adhesion and propulsion interact to produce movement. The researchers sought to identify conditions that lead to super-diffusive behavior.

The researchers tracked the movement of MDA-MB-231 cells in various cluster configurations. They used two-dimensional substrates to simulate dense tissue environments. Cell trajectories were recorded and analyzed for diffusivity patterns. The study compared freely moving cells with cohesive doublets and quadruplets. Computer simulations were conducted using a cellular Potts model. This model replicated experimental conditions to validate findings. Parameters included active self-propelling force and cell-cell adhesion. The model successfully reproduced observed mixing and rotation behaviors.

The study found that moderate cell-cell adhesion enhances diffusivity in dense clusters. Cells in doublets and quadruplets showed increased movement compared to singles. The cellular Potts model confirmed the role of adhesion in promoting mixing. Periodic rotation of cell clusters was observed in both experiments and simulations. The combination of propulsion and adhesion produced super-diffusive behavior. Tuning adhesion and propulsion parameters led to different dynamic states. The most significant result was the enhancement of dispersal through adhesion. These findings suggest a mechanism for cell mixing in tightly packed tissues.

The authors propose that cell-cell adhesion can enhance dispersal in dense populations. The study shows that adhesion and propulsion together generate super-diffusive movement. The cellular Potts model supports the experimental findings. The results suggest that adhesion is not a barrier but a facilitator of movement. The observed rotation and mixing events are attributed to adhesion dynamics. The study highlights the importance of adhesion in collective cell behavior. The findings may apply to tumor metastasis and tissue development. The authors suggest that adhesion can be tuned to control cell dispersal.