title: Tumor-associated Neu5Ac-Tn and Neu5Gc-Tn antigens bind to C-type lectin CLEC10A (CD301, MGL).
abstract: In human tumors, glycoproteins often exhibit abnormal glycosylation patterns, e.g. certain Lewis structures, TF antigen, Tn antigen and/or their sialylated forms, creating additional binding sites for glycoreceptors. In the present study, we have analyzed the carbohydrate specificity of the C-type lectin CLEC10A using glycan profiling by enzyme-linked immunosorbent assay (ELISA). In addition to the known ligands, we show binding to two tumor-associated antigens, namely Neu5Acα2,6-Tn and Neu5Gcα2,6-Tn, with an affinity of CLEC10A in the micromolar range. Detailed analyses of the glycan-lectin interactions were carried out by surface plasmon resonance (SPR) and saturation transfer difference (STD) NMR. CLEC10A binds Neu5Acα2,6-Tn and Neu5Gcα2,6-Tn with dissociation constants of 297 and 80 µM, respectively, as determined by SPR. Comparison of the STD nuclear magnetic resonance (NMR) binding epitopes of Tn and Neu5Acα2,6-Tn revealed a constant binding mode of the N-acetylgalactosamine moiety. This finding is in good agreement with binding studies of CLEC10A transfectomas, which show a well-defined interaction of transmembrane CLEC10A with 6-sialylated-Tn structures. Since both Neu5Acα2,6-Tn and Neu5Gcα2,6-Tn together with the previously known Tn antigen are expressed in human tumors such as mammary carcinoma, the interaction with CLEC10A expressed by macrophages and dendritic cells could be of major functional significance in tumor progression.
authors.affiliation: Institute of Clinical Chemistry, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
authors.forename: Naghmeh
authors.initials: N
authors.lastname: Mortezai
authors.forename: Henning N
authors.initials: HN
authors.lastname: Behnken
authors.forename: Anna-Katharina
authors.initials: AK
authors.lastname: Kurze
authors.forename: Peter
authors.initials: P
authors.lastname: Ludewig
authors.forename: Friedrich
authors.initials: F
authors.lastname: Buck
authors.forename: Bernd
authors.initials: B
authors.lastname: Meyer
authors.forename: Christoph
authors.initials: C
authors.lastname: Wagener
mesh_terms: D000818:Animals; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000737:chemistry / Q000378:metabolism*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D057809:HEK293 Cells; D006801:Humans; D037181:Lectins, C-Type / Q000378:metabolism*; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D009438:Neuraminic Acids / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; C545222:CLEC10A protein, human; D037181:Lectins, C-Type; D009438:Neuraminic Acids; C040286:Tn antigen; C032592:N-glycolylneuraminic acid; D019158:N-Acetylneuraminic Acid
keywords: carbohydrate recognition domain (CRD); carbohydrate–protein interactions; lectin; sialyl-Tn; tumor-associated glycans