Fig. 3. Shear flow modulation of -catenin signaling is ECM substrate- and integrin-dependent. (A) SW480 cells in static culture were transfected with TOPFLASH. (B) SW480 cells were transfected with TOPFLASH, incubated on glass, laminin or fibronectin, and exposed to 15 dyn/cm² of shear stress for 12 hours. (C,D) SW480 cells transiently transfected with TOPFLASH were treated with 5, 6, 1 (10 µg/ml) or 4 (40 µg/ml) anti-integrin antibody for 2 hours. Cells were then plated on laminin and exposed to 15 dyn/cm² of shear stress (C) or static (D) conditions for 12 hours. (E,F) Shear flow negatively regulates -catenin signaling through PI 3-kinase and Rac1. (E) SW480 cells were transiently transfected with the indicated plasmids and exposed to 15 dyn/cm² of shear stress for 12 hours. (F) SW480 cells were transiently transfected with the indicated plasmids and exposed to 15 dyn/cm² of shear stress for 12 hours. All experiments were performed in triplicate with consistent and repeatable results. Asterisk indicates significant difference in comparison with control (Student's t-test, P<0.01).