Fig. 3.

Free-cell perimeter determines leader-cell formation in control, but not compressed cultures. Shown are morphological changes and cell migration rates when 67NR cell monolayers (yellow and gray) were patterned into circles (A), rosettes (C), and squares (F) and cultured under stress-free (control) or compressed (5.8 mmHg) conditions. Solid and open triangles represent edge cells and point/corner cells, respectively (n = 6–8). (Scale bar, 100 μm.) (B) Average migration speed of control and compressed cells in circle patterns (n = 6–7; *P < 0.005). (D) Average migration speed of edge cells and point cells in the uncompressed cultures (n = 17; **P < 0.05 compared with edge cells). (E) Average migration speed of control and compressed cells in rosette patterns (n = 13–17; *P < 0.005). (G) Square patterns (500 × 500 μm) distort due to cell migration, and this pattern distortion can be quantified using a shape change index. For compressed cells, the index is ∼1, suggesting that the square pattern expands uniformly around the boundary; in contrast, control samples had much higher indexes, indicating that the shape expanded preferentially along the diagonals (n = 6; *P < 0.005).