FIGURE 3.

Local 3D deformation of the collagen matrix during tumor cell migration in the presence and absence of protease inhibitors. (A–C) 3D trajectories (reported to an arbitrary origin) of randomly selected beads embedded in a collagen matrix for control HT-1080 fibrosarcoma cells (A), PI cocktail-treated HT-1080 cells (B), and far away from any cell (C). Beads were tracked in 3D for 90 min and their initial positions in the matrix were subtracted. (D) Changes in the distances between beads and points on a migrating HT-1080 cell treated with PI cocktail (see details in Fig. 2). (E–G) Analysis of the bead trajectories for 90-min 3D tracking in terms of their averaged total movement, l_t (E); averaged maximum displacement (maximum excursion from their initial position), l_max (F); and averaged ratio of the net distance between initial and final positions of the bead, l_f, and the total movement (G). ***p < 0.001. For panels D–G, at least five individual PI-treated cells were probed and a total of at least 50 beads were tracked in 3D per condition.