Figure 8. The effect of Concanavalin A (Con A) on the subcellular localization of membrane-type matrix metalloproteinase 1 (MT1-MMP) and processing of pro-MMP-2 in HT-1080 and PC-3 cells. HT-1080 and PC-3 cells were grown for 24 hours in serum-free media containing 5 µM of BB-94 (matrix metalloproteinase inhibitor) (A and C, respectively) and 50 µg/mL of Con A (B and D, respectively), and MT1-MMP localization was detected by the use of a fluorescein isothiocyanate (FITC)-labeled anti–MT1-MMP antibody and immunofluorescent microscopy. HT-1080 (E) and PC-3 (F) cells were also grown in HT-1080–conditioned media with varying concentrations of Con A (0, 0.6, 1.9, 5.6, 16.6, and 50 µg/mL; lanes 1 through 6). Activation of pro-MMP-2 in the HT-1080–conditioned media was examined by gelatin zymography. Both HT-1080 and PC-3 cells showed intracellular localization of MT1-MMP (A, C). HT-1080 cells responded to Con A with translocation of MT1-MMP from these intracellular sites to the cell surface (B) and also with molecular processing of pro-MMP-2 to lower-molecular-weight forms (E). PC-3 cells, on the other hand, showed no change of subcellular localization of MT1-MMP (D) or any processing of pro-MMP-2 (F).