Guidance of Cell Migration by Mechanical Interactions

Lo et al., Biophys. J. 79:144-152 (2000)

The direction and rate of cell migration are well known to be sensitive to chemical factors. To test if cell migration is also sensitive to mechanical interactions with the substrate, 3T3 fibroblasts were plated on substrates of different flexibility, or subject to mechanical forces by pulling or pushing the underlying flexible substrates.

3T3 Fibroblasts Migrate Away from Soft Substrates

NIH 3T3 cells were plated on polyacrylamide substrates with a transition in flexibility. The soft side is marked with fluorescent beads. Cells avoid the soft substrate as they approach the boundary from the stiff side. Recording time, 138 min.

3T3 Fibroblasts Migrate Toward Stiff Substrates

NIH 3T3 cells were plated on polyacrylamide substrates with a transition in flexibility. The soft side is marked with fluorescent beads. Cells turn toward and enter the stiff side as they approach the boundary from the soft side. Recording time, 230 min.

3T3 Fibroblasts Migrate Toward Stretching Forces

NIH 3T3 cells were plated on flexible polyacrylamide substrates. Pulling forces are exerted by inserting a blunted needle into the substrate near the trailing end of this cell and dragging the substrate away from the cell. The cell switches the direction by expanding secondary protrusions toward the needle to form a leading lamellipodium. Recording time, 109 min.

3T3 Fibroblasts Migrate Away from Compressing Forces

NIH 3T3 cells are plated on flexible polyacrylamide substrates. Pushing forces are exerted by inserting a blunted needle into the substrate near the leading edge of an approaching cell and moving toward the cell. The cell switches the direction by retracting the leading lamellipodium and expanding protrusions elsewhere. Recording time, 88 min.