Fig. 5.

Altering the motility strategy of metastatic cancer cells. Examples of typical cell trajectories: Lévy walking (control MDA-MB-231 cells, a or with Rac1 inhibited, b), ballistic (Myosin II inhibited, c) diffusive (Arp2/3 inhibited, d). Line width = 20 μm, same for all three images. In displacement plots, ten representative trajectories for each treatment are shown. Quantification of motility characteristics (exponents μ, α along with the ± 95% confidence intervals) for MDA-MD-231 cells moving on microtracks and having individual actin-binding proteins inhibited is summarized in Table 3. e Log–log plots of the cells’ mean square displacement versus time, $⟨x^2⟩=t^{\alpha }$. The slopes correspond to exponents α; note that inhibition of Arp2/3 with CK666 results in diffusive motion, α ~ 1, while inhibition of Myosin II results in ballistic motion, α~2. f The corresponding cumulative frequency distributions, CFDs, of persistence times. Markers are experimental statistics for persistence times. Solid lines are truncated power law fits with respective μ values shown in Table 3. For the chemical inhibitors data shown corresponds to: 40 μM CK666 (for Arp2/3, yellow crosses), 100 μM NSC23755 (Rac1, green triangles), 10 μM Blebbistatin (Myosin II, red rectangles), and control (black circles). The additional results for all drug and siRNA concentrations tested are shown in Supplementary Figures 10–13. See Supplementary Movies 9–12 and 16–18