Effects of MMP and PAS inhibitors on MDA-231 cell mediated degradation of non-mineralized matrix. MDA-231 breast cancer cells (105 cells/well) were cultured for 24 h on 3H-labelled extracellular matrices in the presence of 2 ug/ml of human plasminogen, TGFβ (10-10 M) with and without CT1166 (10-5 M), TIMP-1 (50 ug/ml), aprotinin (10-5 M), antibodies to human uPA (50 μg/ml) or human uPAR (50 μg/ml). After 24-h incubation, bone matrix degradation was measured as described in Materials and methods. This experiment was repeated twice. The results are expressed as percentage release of degradation of 3H labelled bone matrix. Each bar is the mean ± S.E.M. of six wells. The effects of the inhibitors were statistically significant *P < 0.05;***P < 0.001.