Effect of FVIIa on tumor cell invasion. MDA-MB-231 cells were placed on top of a Matrigel barrier. FVIIa and other agonists were added to a lower well that contained NIH3T3 cell–conditioned media. At the end of a 48-hour incubation period at 37°C, the number of cells that migrated across the Matrigel barrier to the underside of the membrane was determined. Concentrations of various reagents used were: FVIIa, 50 nM; thrombin, 10 nM; PAR-2 AP, 50 μM; rabbit antihuman IL-8 IgG, 50 μg/mL; rabbit anti–PAR-2 IgG, 500 μg/mL; control IgG, 50 μg/mL (1) or 500 μg/Ml (2). Mean ± SEM, n = 3 to 5. ^*Inhibition was statistically significant.