DR3 mediates the adhesion of colon cancer cells to E-selectin-expressing endothelial cells in a laminar flow chamber. A to C. HUVECs were stimulated with 20 ng/mL of IL-1β for 4 h. Live HT29 cells (2 × 106 per assay) stained with Calcein AM were treated with anti-DR3 blocking antibody (B65) or with a control irrelevant antibody (Ctrl: MOPC21) for 30 min prior to being introduced in the circulating medium. D to F. The knockdown of DR3 expression in HT29 was performed by small interfering RNA (siDR3). siRNA targeting unrelated mRNAs was used as control (Ctrl). Following treatment, HT29 cells were placed in a laminar flow chamber under a shear stress of 1 dyne/cm2 as in A. In A and D, the cells attached to the endothelium were counted after 25 min in more than 5 fields per condition. *p < 0.01 (Student t test using the IL-1β condition as reference). In B, C, E and F, representative fields are shown.