Figure 2

Elastase inhibition reduces tumor cell invasion and growth of xenografts. A) MDA-MB-231 cells stably expressing control, scrambled shRNA (231-Control1 and 231-Control2) or elastase-specific shRNA (231-Elastase1 and 231-Elastase2) were assessed for invasion of a collagen matrix at baseline and after 48 h. B) The percentage of the collagen matrix field that was invaded by each clone was quantified for triplicate wells and the mean was graphed. Significance was measured using a Student's t-test (*P < 0.01). C) Cells were also subjected to a scratch assay to detect the percentage of a scratched field that would be replaced by migrating cells within 12 hours. D) Three different replicates of scratch assay were performed and the average was calculated along with the standard error (shown as bars) and the P-value was calculated using a Student's t-test (*P < 0.05 compared to 231- Control 2,**P < 0.01 compared to both control clones). E and F) Cells transfected with nonspecific shRNA (control) or elastase-specific shRNA were injected into the mammary fat pad of mice, and tumor formation was observed and measured for five weeks. The results show the average of two replicate experiments.