Figure 3

Highlighting membrane ruptures in migrating MDA-MB-231 cells. MDA-MB-231 cells were seeded on a glass coverslip coated with collagen I for 24 h, then incubated for 1 h at 37 °C with 2.5 µM Fluo-4-AM (white) and finally kinetics study using fluorescence microscopy was performed for 2 h. (a) Images in phase-contrast microscopy were acquired before and after the kinetics study. (b) Fluorescence intensity variations of intracellular Fluo-4-AM studied in the course of time. Each colored arrow points out a cell of interest exhibiting a strong variation of the fluorescence intensity. A strong increase of fluorescence intensity is particularly observed at t = 32 min (blue and red arrows) and t = 85 min (green arrow). A recovery of fluorescence intensity to a basal level is observed at t = 34 min (blue and red arrows) and t = 86 min (green arrow). Scale bar: 100 µm. (c) Quantification of intracellular fluorescence intensity in arbitrary unit (a.u.) measured in cells presented in b during the two hours of migration. The color of each line corresponds to the color of the arrow in (b).