Figure 1.

In vitro MMP inhibitory activity of doxycycline. (A) Zymography gel (light-dark reversed for clarity) of the in vitro effect on MMP-9 and MMP-2 activities by doxycycline. In U251 glioma cells overexpressing EGFR, doxycycline blocked completely MMP-9 gelanolytic activity at 500 μg/ml, while it only blocked partially MMP-2 activity at 1,000 μg/ml. (B) Normalized band intensity of gelanolytic activity of MMPs from U251 cells overexpressing EGFR at increasing concentrations of doxycyline. The IC₅₀ was estimated to be 75 μg/ml for MMP-9 (red), while it was 500 μg/ml for MMP-2 (blue). Data are means +/- SEM, n = 4.