The effect of NS-398 on metalloproteinase release in culture media by MDA-231 cells. These cells were cultured in the presence or absence of increasing concentrations of NS-398 for 24 h. The secretion of the pro and active form of MMPs was determined by EIA. A) MMP-1 B) MMP-9. MMP-2, MMP-3, MMP-10 and MMP-13 were not detected in MDA-231 media. Values were significant (*p < 0.05) when compared to untreated controls (0 μM NS-398).