Fig. 4.

Effects of inorganic sulfur on MMP-2 and MMP-9 activity in MDA-MB-231 cells. Cells were plated in 6 well plates at a density 1 × 10³ cell/mL in DMEM/F12 supplemented with 10% FBS. After 48 h of incubation, the monolayers were incubated in the presence of various concentrations of inorganic sulfur (0, 12.5, 25, 50 µmol/L) for 24 h. The medium was collected and concentrated for zymography. A-a) Photographs of MMP-2, A-b) Quantitative analysis of the bands. B-a) Photographs of MMP-9 bands, B-b) Quantitative analysis of the bands. The enzyme activity was expressed as a percentage of the control (without inorganic sulfur). Each bar represents the mean ± SE of 3 independent experiments. Significant differences (P < 0.05) among groups are indicated by different letters above each bar.