FIGURE 7.

Effect of galectin-3 multivalency on phosphorylation of ERK1/2 and Akt through the binding of galectin-3 to MUC1. A, galectin-3 treated with collagenase type VII (cleaved) or PBS (intact) as described under “Experimental Procedures” was subjected to SDS-PAGE, followed by Coomassie Brilliant Blue staining. B, after exclusion of galectin-3 from the cell surface and subsequent preincubation with the EGFR inhibitor as described in Fig. 6A, HCT116/MUC1 cells were treated with intact galectin-3, cleaved galectin-3 (40 μg/ml, respectively), or PBS (vehicle) for 10 min, and then phosphorylated ERK1/2, total ERK1/2, phosphorylated Akt, and total Akt were determined as described in Fig. 5 (C–E). C and D, the intensities of the bands in Fig. 7B were determined as described in Fig. 5 (F and G). The ratios obtained from PBS-treated HCT116/MUC1 cells were taken as 1 (means ± S.D., n = 3). **, p < 0.01.