Studies of Mesenchymal and Amoeboid Migration on Compliant Substrates

Abstract

Biological cells are constantly subjected to mechanical forces in their extracellular matrix (ECM). Studies have also shown that cells mainly utilize two different migration strategies: actin-polymerization driven migration (mesenchymal) and bleb-driven migration (amoeboid). However, little is known about the interplay of ECM physical variables in determining cellular response and migration strategies.

Cell-substrate adhesivity and ECM rigidities appears to be important regulators in mesenchymal migration. We found that mesenchymal migration speed is a biphasic relationship with substrate rigidity with maximal speed at intermediate rigidities. Focal adhesion size was also observed to increase with substrate rigidity. Cells were also found to maintain constant substrate strain at low substrate rigidities and constant traction stress at high substrate rigidities.

Conversely, amoeboid migration speed is independent of substrate rigidity. Instead, cell speed showed a biphasic relationship with increasing cell confinement. A computational model of blebbing cells was proposed and results suggest that amoeboid motility is regulated by intracellular pressure and cell-membrane to actin-cortex adhesions.