Cdc42 depletion specifically reduces cancer cell adhesion and spreading to ECM. PC3 cells were transfected with the indicated siRNAs. (A) Confocal stack images of PC3 cells labeled with CFSE (green) and added to HUVECs for 4 h. Cells were stained with DAPI (blue) and for F-actin (red). Z views show cell height. Bar, 18 µm. (B) Time-lapse stills (Video 2) of PC3 cells on ECs. Bar, 50 µm. (C) Time-lapse stills (Video 3) of PC3 cells on fibronectin. Bar, 50 µm. (D) Kymographs (right panels) from time-lapse movies of cells plated on fibronectin. First and last images of time-lapse movies are shown (left panels); arrows represent where the kymographs were made. Blebbing regions are indicated with white brackets (bottom right panel). Cell adhesion to fibronectin- (E) or Matrigel-coated (F) dishes at 15 min. Data (E and F) are expressed as the percentage of control cells. Values are means ± SEM (error bars; n ≥ 3); ***, P < 0.001; **, P < 0.01; *, P < 0.05.