title: Selectin Ligands Sialyl-Lewis a and Sialyl-Lewis x in Gastrointestinal Cancers.
abstract: The tetrasaccharide structures Siaα2,3Galβ1,3(Fucα1,4)GlcNAc and Siaα2,3Galβ1,4(Fucα1,3)GlcNAc constitute the epitopes of the carbohydrate antigens sialyl-Lewis a (sLea) and sialyl-Lewis x (sLex), respectively, and are the minimal requirement for selectin binding to their counter-receptors. Interaction of sLexexpressed on the cell surface of leucocytes with E-selectin on endothelial cells allows their arrest and promotes their extravasation. Similarly, the rolling of cancer cells ectopically expressing the selectin ligands on endothelial cells is potentially a crucial step favoring the metastatic process. In this review, we focus on the biosynthetic steps giving rise to selectin ligand expression in cell lines and native tissues of gastrointestinal origin, trying to understand whether and how they are deregulated in cancer. We also discuss the use of such molecules in the diagnosis of gastrointestinal cancers, particularly in light of recent data questioning the ability of colon cancers to express sLeaand the possible use of circulating sLexin the early detection of pancreatic cancer. Finally, we reviewed the data dealing with the mechanisms that link selectin ligand expression in gastrointestinal cells to cancer malignancy. This promising research field seems to require additional data on native patient tissues to reach more definitive conclusions.
authors.affiliation: Department of Medicine and Surgery (DMC), University of Insubria, 21100 Varese, Italy. marco.trinchera@uninsubria.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Trinchera
authors.affiliation: Department of Health Sciences, San Paolo Hospital, University of Milan, 20142 Milano, Italy. adele.aronica@unimi.it.
authors.forename: Adele
authors.initials: A
authors.lastname: Aronica
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, 40126 Bologna, Italy. fabio.dallolio@unibo.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Dall'Olio
keywords: cancer diagnosis; cancer malignancy; carbohydrate antigens; glycosylation