FIGURE 1.

p40 stimulates ligand release from intestinal epithelial cells to activate EGFR. A, conditioned medium (CM) was collected from YAMC and T84 cells treated with p40 (10 ng/ml) for 60 and 120 min. YAMC and T84 cells were treated with p40 (10 ng/ml) for the indicated times or conditioned medium for 10 min. B, YAMC and T84 cells were treated with p40 (10 ng/ml) for 60 min or EGF (10 ng/ml for YAMC and 30 ng/ml for T84 cells) for 5 min in the presence or absence of 1-h pretreatment with metalloproteinase inhibitors, GM6001 (2.5 μm) and TAPI-1 (10 μm), or an antibody blocking human EGF receptor ligand binding (C225, 5 nm). Cellular lysates were collected for Western blot analysis of total EGFR and Akt levels and EGFR (Tyr-1068) and Akt (Ser-473) phosphorylation. β-Actin protein levels were used as loading controls. Data are representative of at least three separate experiments.