Micropillar-integrated device for monitoring dynamic regulation of traction forces during cell migration

Cell migration plays an important role in many physiological and pathological processes such as morphogenesis, wound healing, and tumor metastasis. Although the majority of such events occur with cells moving as a group, called collective cell migration, mechanics of collective cell migrations has not been understood well compared to a single cell migration. Mechanical interactions between cells and their surroundings have been demonstrated to regulate cell migration. One of such interactions is the induction of traction forces by acto-myosin dynamics within cells to their local environment, as it has been reported that cells alter the magnitude of traction forces depending on the stiffness of attaching substrates. In connection with cell migration, it has also been demonstrated the importance of substrate stiffness during cell migration using microfabricated substrates consisting of arrays of micropillars. To understand the mechanics of collective cell migration, it is important to know how cells within a moving cell collectivity generate forces to move the collectivity forward at single cell level. Accordingly, the present study was performed to clarify the mechanics of collective cell migration by measuring traction forces exerted by mouse NIH 3T3 fibroblasts using a newly developed migration assay device.