Figure 5
Effect of mifepristone on cytoskeletal actin fibers and tubulin filaments. SKOV-3 (A), U87MG (B), MDA-MB-231 (C) or LNCaP (D) cells were cultured in the presence of vehicle (VEH) or a cytostatic concentration of mifepristone (MF) for 72 h, following which immunofluorescence was used to visualize the cytoskeletal protein α-tubulin. AlexaFluor® 594 phalloidin was utilized to visualize F-actin and DAPI to label cell nuclei. Images were taking using confocal microscopy. Scale bar = 50 μm. The inset in panel D represents a cell that was in a different field within the same image and that denotes the characteristic increase in membrane ruffles induced by MF (for the complete image see Additional file 4: Figure S4). In A-D, long, thin arrows, cortical actin; short, thin arrows, stress fibers; arrowheads, lamellipodia; short, wide arrows, membrane ruffles. Panel E represents the quantification of the membrane ruffles in culture for all cell lines studied in response to MF. Ruffles were counted from confocal microscopy images. We expressed membrane ruffling as number of ruffles counted every 25 cells, after assessing a minimum of 75 cells and a maximum of 250 cells per experimental group, according to the density of the cell culture. *** p < 0.01 vs. VEH (Student’s t-test).