Integrin αvβ6 sustains and promotes tumor invasive growth in colon cancer progression

Figure 5 Effects of cell density on matrix metalloproteinase-9 secretion. A: Wild-type WiDr and SW480 cells and β6 SW480 transfectants were analyzed by FACScan for integrin αvβ6 expression. The pale and black histograms represent analyses in the absence and presence of E7P6 primary antibody; the secondary antibody (goat anti-mouse IgG) was conjugated with phycoerythrin; B: Gelatinase B assay (Biotrak) showing levels of matrix metalloproteinase-9 (MMP-9) in TCM (20-fold concentrated). The data represent the mean MMP-9 levels per cell for three experiments; in each experiment, the TCM samples were tested in duplicate; C: Gelatin zymogram showing gelatinase activity in non-concentrated TCM from β6 SW480 (+β6) and wild-type SW480 cells (-β6) cultured at low (L) and high (H) densities. The position of purified MMP-9 (M) is shown on the left; D: Gelatin zymogram showing gelatinase activity in non-concentrated conditioned medium from HaCaT cells cultured at low (L) and high (H) densities. The position of purified MMP-9 (M) is shown on the right.