Loss of ARHGAP17 promotes matrix degradation in MDA-MB-231 cells and increased invasion in SUM159 cells. (A) Representative micrographs of F-actin–stained MDA-MB-231 cells degrading fluorescent-gelatin (scale bar, 20 μm; inset scale bar, 5 μm). (B) Quantification of matrix degradation by MDA-MB-231 cells. Results are expressed as mean ± SEM of three independent experiments in which at least 10 random FOVs per condition per experiment were measured. Significance was tested with a two-tailed t test: **, P < 0.01. (C) Representative optical sections of the inverse invasion assay of SUM159 cells expressing Scarlet-CAAX. Arrowheads highlight cell protrusions into the matrix. The zoomed regions are marked by a dashed line (scale bar, 100 μm; zoom scale bar, 10 μm). (D) Representative Z-view of inverse invasion assay with brightest point projection in the y-axis (scale bar, 20 μm). Yellow dashed lines indicate 20 μm above the coverslip. (E) Quantification of area invaded by cells in the inverse invasion assay. Invasion was quantified by measuring signal intensity at 20 μm above the coverslip. Results are expressed as mean ± SEM of three independent experiments in which at least three FOVs per condition per experiment were measured. Significance was tested with a two-tailed t test: *, P < 0.05; ***, P < 0.001.