Dulbecco's modified Eagle's medium nutrient mixture F-12 (DMEM/F-12), PBS, fetal bovine serum, trypsin-EDTA, and gentamicin were all obtained from Invitrogen-Gibco (Carlsbad, CA). Bovine serum albumin (BSA), recombinant bovine insulin, cholera toxin, recombinant human epidermal growth factor, a mouse monoclonal antibody to myosin light chain (MLC), and a protease inhibitor cocktail were all from Sigma-Aldrich (St. Louis, MO). Six- or 24-well transwell plates as well as 24-well culture plates were obtained from Corning (Corning, NY). Rabbit polyclonal antibodies to the p65 subunit of NF-κB and mouse monoclonal antibodies to IκB-α or to phosphorylated IκB-α were obtained from Santa Cruz Biotechnology (Santa Cruz, CA). Rabbit polyclonal antibodies to phosphorylated MLC were from Cell Signaling (Danvers, MA), whereas those to ZO-1 or to occludin were from Zymed (San Francisco, CA). Mouse monoclonal antibodies to E-cadherin or to β-catenin were obtained from BD Biosciences (Carlsbad, CA). Cyto59, horseradish peroxidase–conjugated, or AlexaFluor 488–labeled goat antibodies to mouse or rabbit immunoglobulin G, and rhodamine-phalloidin were from Invitrogen-Gibco. ECL Plus reagents were obtained from GE Healthcare (Little Chalfont, UK). 2-(4-Chlorobenzamido)-3-[2(1H)-quinolinon-4-yl]propionic acid (rebamipide) was obtained from Tokyo Chemical Industry (Tokyo, Japan). Rebamipide ophthalmic suspension (2%) and vehicle (the same solution without rebamipide) were formulated at Otsuka Pharmaceutical Co., Ltd. (Ako, Hyogo, Japan).