title: Precise structural analysis of O-linked oligosaccharides in human serum.
abstract: O-glycans are suitable targets as novel and useful tumor markers. The structures of O-glycans in human sera from four healthy controls were precisely analyzed to obtain the reference O-glycan database. O-glycans were prepared from sera by hydrazine treatment followed by fluorescent labeling with aminopyridine and identified using two-dimensional mapping, enzymatic digestion and mass spectrometry (MS) together with methanolysis and the use of newly synthesized sulfated oligosaccharides as standards. O-glycans, present at more than 0.01% of the total O-glycans, were analyzed, and 18 kinds of acidic and 2 kinds of neutral glycans were identified. NeuAcα2-3Galβ1-3N-acetylgalactosamine (GalNAc) (61-64%), NeuAcα2-3Galβ1-3(NeuAcα2-6)GalNAc (15-26%) and Galβ1-3GalNAc (6-14%) were major components while other sialylated glycans, Galβ1-3(NeuAcα2-6)GalNAc, Galβ1-4GlcNAcβ1-6(NeuAcα2-3Galβ1-3)GalNAc and NeuAcα2-3Galβ1-4GlcNAcβ1-6(NeuAcα2-3Galβ1-3)GalNAc were relatively minor components, accounting for ∼1-2%. Very minor glycans accounting for ∼0.01-0.1% of the total include (i) the neutral glycan, Galβ1-4GlcNAcβ1-6(Galβ1-3)GalNAc, (ii) sialylated glycans, having sialyl Tn antigen, agalacto and trisialylated structures, (iii) fucosylated glycans forming blood type H antigen, blood type A antigen, blood type B antigen, Lewis X antigen and sialyl Lewis X antigen and (iv) sulfated glycans, having 6-sulfo and 3'-sulfo structures. Two kinds of clinically applied tumor markers namely sialyl Tn antigen and sialyl Lewis X antigen in healthy controls sera were revealed to be present at ∼0.1-0.2% of the total. However, other markers such as CA19-9 and DU-PAN-2 were not found, suggesting the relative amounts of these glycans to be <0.01%. These detailed O-glycan profiles will help to find novel carbohydrate tumor markers.
authors.affiliation: Department of Immunology, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-2 Nakamichi, Higashinari-ku, Osaka 537-8511, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Yabu
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Korekane
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Miyamoto
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D005732:Gangliosides; D006031:Glycosylation; D006801:Humans; D009369:Neoplasms / Q000097:blood* / Q000473:pathology; D009844:Oligosaccharides / Q000097:blood*; D011134:Polysaccharides / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor; D005732:Gangliosides; D009844:Oligosaccharides; D011134:Polysaccharides; C086047:disialosyl galactosyl globoside
keywords: O-glycan; mass spectrometry; serum; two-dimensional mapping