Defining the glycophenotype of squamous epithelia using plant and mammalian lectins. Differentiation-dependent expression of alpha2,6- and alpha2,3-linked N-acetylneuraminic acid in squamous epithelia and carcinomas, and its differential effect on binding of the endogenous lectins galectins-1 and -3.
A thorough characterization of the properties of squamous epithelial cells is necessary in order to improve our understanding of the functional aspects of normal development and malignant aberrations. Up to now, studies have focused almost exclusively on monitoring distinct protein markers. With our growing awareness of the coding function of glycan chains of cellular glycoconjugates and their interaction with receptors (lectins) in situ, defining the glycophenotype of these cells has become an important issue. Whereas the commonly applied plant lectins are tools used to map the presence and localization of biochemically defined saccharide epitopes, the introduction of endogenous (mammalian) lectins to this analysis enables us to take the step from monitoring the presence of glycan to understanding the functional implications by revealing ligand properties of the detected epitope for tissue lectin. Thus, in this study we investigated a distinct aspect of glycosylation using plant and mammalian lectins, i.e. the linkage type of sialylation. We first mapped the expression profile of the type of sialylation (alpha2,3- or alpha2,6-linked) by plant lectins. Based on the hypothesis that this factor regulates accessibility of ligands for endogenous lectins we introduced two labeled galectins to this study. Galectin-3 (but not galectin-1) binding was related to cell differentiation in normal adult and developing epithelia, cultured epidermal cells, and carcinomas derived from these epithelia. The presented data suggest that alpha2,6-linked N-acetyl-D-neuraminic acid moieties could serve to mask galectin-3-reactive glycoepitopes. As a consequence, monitoring of the linkage type of sialic acid in glycans by plant lectins therefore has implications for the extent of glycan reactivity with endogenous lectins, pointing to a potential function of changes in sialylation type beyond these cell and lectin systems.
Holíková
Zuzana
Z
Charles University, 1st Faculty of Medicine, Institute of Anatomy, Prague, Czech Republic.
Hrdlicková-Cela
Enkela
E
Plzák
Jan
J
Smetana
Karel
K
Betka
Jan
J
Dvoránková
Barbora
B
Esner
Milan
M
Wasano
Kojiro
K
André
Sabine
S
Kaltner
Herbert
H
Motlík
Jan
J
Hercogová
Jana
J
Kodet
Roman
R
Gabius
Hans-Joachim
HJ
D000818:Animals; D015415:Biomarkers; D002294:Carcinoma, Squamous Cell / Q000737:chemistry* / Q000473:pathology; D002454:Cell Differentiation; D002478:Cells, Cultured; D002642:Chick Embryo; D000078404:Epidermal Cells; D004847:Epithelial Cells / Q000737:chemistry* / Q000166:cytology; D037483:Galectin 1 / Q000378:metabolism*; D037502:Galectin 3 / Q000378:metabolism*; D006001:Glycoconjugates / Q000032:analysis* / Q000096:biosynthesis; D006031:Glycosylation; D006801:Humans; D007822:Laryngeal Neoplasms / Q000737:chemistry* / Q000473:pathology; D037102:Lectins / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D019158:N-Acetylneuraminic Acid / Q000032:analysis* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000737:chemistry; D009928:Organ Specificity; D010641:Phenotype; D037121:Plant Lectins / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D012799:Sialyltransferases / Q000378:metabolism; D013194:Staining and Labeling; D013552:Swine; D014062:Tongue Neoplasms / Q000737:chemistry* / Q000473:pathology; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase
D015415:Biomarkers; D037483:Galectin 1; D037502:Galectin 3; D006001:Glycoconjugates; D037102:Lectins; D009363:Neoplasm Proteins; D037121:Plant Lectins; D012799:Sialyltransferases; D019158:N-Acetylneuraminic Acid; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase