FIGURE 1.

Knockdown of Fascin inhibits the assembly of actin filaments and the formation of pseudopodia. A and B, MCF‐7 and MDA‐MD‐231 cells were transfected with negative control (NC) and siRNA targeting Fascin (si‐Fascin). The expression of Fascin was determined by Western blotting. C and D, The morphology of actin filaments showed a short and curved state in Fascin‐knockdown MCF‐7 cells compared with NC cells. The number of actin filaments (length > 10 μm) and the longest actin filament in Fascin‐downregulated MCF‐7 cells were counted. Actin filaments were labelled with red fluorescently labelled phalloidin. Endogenous Fascin was incubated with anti‐Fascin antibody and green fluorescent protein secondary antibody. The nucleus was stained with DAPI (blue). Bar, 10 μm. E and F, MDA‐MD‐231 cells transfected with si‐Fascin and/or 3HA‐Fascin were detected for invadopodia formation in a 3.0 μm porous Boyden chamber. Invadopodia on the lower side of the membrane were treated with cortactin antibody and counted per field of microscope. Bar, 10 μm. Objective lens, magnification, ×40; numerical aperture, 0.95. *P < .05. **P < .01. ****P < .0001