(A) Immunoblots were performed on lysates from SK-CO15 cells treated with GSK-3 alpha and beta siRNA, Scramble siRNA or Mock treatment. Compared to controls, GSK-3 siRNA treatment reduced protein levels of GSK-3, E-cadherin, Occludin and Claudin-1. JAM-A and ZO-1 expression was not consistently changed. (B) Chemical inhibition of GSK-3 kinase activity decreases Occludin, Claudin-1 and E-cadherin expression. Immunoblots were performed on lysates from MDCK cells treated SB415286 or Mock treatment. Compared to controls, SB415286 treatment reduced protein levels of E-cadherin, Occludin and Claudin-1. For A&B, Actin blots are shown as a loading control. Immunoblots are representative of at least three experiments.