Migration of cells in confluent monolayers. (A) Migration of fluorescence-labeled cells cocultured with nonlabeled cells. Time-lapse images were acquired at 9-min intervals for 6 h. Tracks of some labeled cells, which are shown in yellow, are overlaid with the last frame shot of a representative video in the top panels, where phase-contrast images are also shown. Representative tracks are collected in the bottom panels. (B) Statistic analysis of the instantaneous velocities of cells. Comparison of each experimental group with the control cells (n = 76) shows a significant difference for OL-pc (*, P < 0.05; n = 63) as well as for OL-pcΔNBS (*, P < 0.05; n = 76). Bar, 200 μm.