Fig. 1.

Prerequisites for efficient cell invasion. TEM image of an MDA-MB-231 breast carcinoma cell invading into a 3-D collagen matrix. The ability to invade through connective tissue is governed by the balance between four biophysical processes: 1) contractile force generation, 2) transmission of contractile forces via cell-matrix adhesions (integrin expression, adhesion bond stability, de-adhesion), 3) resisting forces of the cell against cell shape changes (cytoskeletal (CSK) fluidity, dynamics, stiffness)), and 4) resisting forces imposed by the matrix against deformations (enzymatic matrix degradation).