title: Lectin inhibits antigen-antibody reaction in a glycoform-specific manner: Application for detecting α2,6sialylated-carcinoembryonic antigen.
abstract: Carcinoembryonic antigen (CEA) is a glycoprotein marker, which is widely used for diagnosing various cancers, especially colon adenocarcinoma. In addition, CEA mediates homotypic adhesion of colon adenocarcinoma cells, which appears to favor hematogenous metastasis. CEA carries α2,6sialyl residues on its N-glycans whereas a normal counterpart, normal fecal antigen-2, does α2,3sialyl residues, suggesting that cancer-specific  α2,6sialylation on CEA may play a role for cell invasion and metastasis. A simple and rapid estimation of α2,6sialyled CEA in detergent extracts from formalin-fixed colon adenocarcinoma by "lectin inhibition" is reported. In the lectin inhibition method, Sambucus sieboldiana Agglutinin (SSA) lectin, an α2,6sialic acid binder, was used as a glycoform-specific inhibitor for antigen-antibody reaction in ELISA. Detergent extracts from colon adenocarcinoma showed a fair amount of ELISA signal in the absence of SSA whereas the signal was markedly reduced (45≈74%) in the presence of SSA, suggesting that the extracts contains α2,6sialyled CEA. The presence of α2,6sialyled CEA in the extracts was confirmed by lectin microarray, in which SSA, Sambucus nigra agglutinin, and Trichosanthes japonica agglutinin I lectins were used as α2,6sialyl binders. Thus lectin inhibition is a simple and rapid method for detecting α2,6sialyled CEA even in crude detergent extracts from formalin-fixed adenocarcinoma tissue.
authors: Department of Biochemistry, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Hiromi
authors: H
authors: Ito
authors: Department of Biochemistry, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Kyoka
authors: K
authors: Hoshi
authors: Department of Regenerative Surgery, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Fumihiko
authors: F
authors: Osuka
authors: Department of Regenerative Surgery, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Mitsukazu
authors: M
authors: Gotoh
authors: Aizu Medical Center, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Takuro
authors: T
authors: Saito
authors: Aizu Medical Center, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Hiroshi
authors: H
authors: Hojo
authors: Department of Gastroenterology and Rheumatology, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Rei
authors: R
authors: Suzuki
authors: Department of Gastroenterology and Rheumatology, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Hiromasa
authors: H
authors: Ohira
authors: Division of Human Life Science, Fukushima Medical University School of Nursing, Fukushima City, Japan.
authors: Takashi
authors: T
authors: Honda
authors: Department of Biochemistry, Fukushima Medical University School of Medicine, Fukushima City, Japan.
authors: Yasuhiro
authors: Y
authors: Hashimoto
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D000937:Antigen-Antibody Reactions; D014408:Biomarkers, Tumor / Q000032:analysis / Q000378:metabolism; D002272:Carcinoembryonic Antigen / Q000032:analysis* / Q000378:metabolism; D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D006031:Glycosylation; D006801:Humans; D019158:N-Acetylneuraminic Acid / Q000032:analysis* / Q000378:metabolism; D037121:Plant Lectins / Q000378:metabolism*; D054788:Ribosome Inactivating Proteins / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D037121:Plant Lectins; C050600:Sambucus nigra lectins; D054788:Ribosome Inactivating Proteins; D019158:N-Acetylneuraminic Acid
keywords: Carcinoembryonic antigen; Colon adenocarcinoma; Glycoproteomics; SSA; Sambucus sieboldiana agglutinin