Significance of carbohydrate antigen sialyl-Lewis X, sialyl-Lewis A, and possible unknown ligands to adhesion of human urothelial cancer cells to activated endothelium

Objective: To assess the contribution of the carbohydrate antigens, sialyl- Lewis X (sLe(x)) and sialyl-lewis A (sLe(a)), which are known to be ligands for E-selectin, to the adhesion between human urothelial cancer cells and cytokine-activated human endothelial cells. Materials and Methods: We studi ed the expression of sLe(x) and sLe(a) antigens of three bladder cancer cel l lines (JTC 30, JTC 32, and T24) by flow cytometry and the adherence to in terleukin 1 beta-activated human umbilical vein endothelial cells (HUVEC). Results: JTC 30 and JTC 32 cells expressed both sLe(x) and sLe(a) antigens, and showed adhesion to activated HUVEC, which was completely abolished by anti-E-selectin antibody. 124 cells expressed neither sLe(x) nor sLe(a) ant igen, and did not adhere to activated HUVEC. Each of anti-sLe(a) or anti-sL e(x) antibody partially blocked the attachment of JTC 30 cells to activated HUVEC, and combination of these antibodies almost completely blocked the a dhesion. The combination of antibodies did not significantly influence the adhesion of JTC 32 cells. Conclusion: These results indicate that both sLe( a) and sLe(x) carbohydrate antigens are involved in E-selectin-mediated adh esion of some urothelial cancers, and that there might be unknown ligands f or E-selectin on urothelial cancer cells. Copyright (C) 2000 S. Karger AG. Basel.