Figure 6.

Increase in MMP activity during tumor regression. Tumors from control, −MPA-, E₂-, and RU486-treated mice were collected at 6, 12, 24, 48, and 72 hours. Tissues were processed for gelatin and casein zymography. A: A representative negative image of a gelatin zymogram for the 72-hour time point. Latent MMP-9 (LMMP-9) and latent and active forms of MMP-2 (LMMP-2, AMMP-2) were detected. B: A representative negative image of a casein zymogram for the 72-hour time point. Latent stromelysin-1 (LSTR-1) was detected. C: Densitometric analysis of samples derived from control and 24-, 48-, and 72-hour-treated mice for LMMP-9, LMMP-2, and AMMP-2. The panel showing the densitometric analysis of LSTR-1 corresponds to control and 72-hour-treated mice. In each case values represent the mean ± SEM of samples derived from three mice. Values corresponding to 6- and 12-hour treatments are not shown because they were not statistically different from controls. Statistical significance of treated samples in relation to the corresponding control are shown as: *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001.