Inhibition of cathepsin B activity attenuates invasiveness of SUM149 cells. SUM149 cells were subjected to transwell invasion assays in the presence of DMSO (vehicle control) or 10 μM CA074. (a) Images are SUM149 cells that have invaded through rBM-coated filters; bar, 150 μm. (b) Quantification of invaded cells was performed by counting the average number of nuclei from 10 fields of view per filter (using Metamorph software) and expressed as percent control. Results from three independent experiments are presented as mean ± standard deviation; *, P < 0.05.