title: Galectin-3 Binding Protein and Galectin-1 Interaction in Breast Cancer Cell Aggregation and Metastasis.
abstract: Galectin-3 binding protein (Gal-3BP) is a large hyperglycosylated protein that acts as a ligand for several galectins through glycan-dependent interactions. Gal-3BP can induce galectin-mediated tumor cell aggregation to increase the survival of cancer cells in the bloodstream during the metastatic process. However, the galectin interacting with Gal-3BP and its binding specificity has not been identified and structurally elucidated, mainly due to the limitation of mass spectrometry in glycan sequencing. To understand the role of Gal-3BP, we here used liquid chromatography-mass spectrometry combined with specific exoglycosidase reactions to determine the sequences of N-glycans on Gal-3BP from MCF-7 and MDA-MB-231 cells, especially the sequences with terminal sialylation and fucosylation, and addition of LacNAc repeat structures. The N-glycans from both strains are complex type with terminal α2,3-sialidic acid and core fucose linkages, with additional α1,2- and α1,3 fucose linkages found in MCF-7 cells. Compared with that from MCF-7, the Gal-3BP from MDA-MB-231 cells had fewer tetra-antennary structures, only α1,6-linked core fucoses, and more LacNAc repeat structures; the MDA-MB-231 cells had no surface galectin-3 but used surface galectin-1 for interaction with Gal-3BP to form large oligomers and cell aggregates. This study elucidates the specificity of Gal-3BP interacting with galectin-1 and the role of Gal-3BP in cancer cell aggregation and metastasis.
authors.forename: Tzu-Wen
authors.initials: TW
authors.lastname: Lin
authors.affiliation: §Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan.
authors.forename: Hui-Tzu
authors.initials: HT
authors.lastname: Chang
authors.forename: Chein-Hung
authors.initials: CH
authors.lastname: Chen
authors.forename: Chung-Hsuan
authors.initials: CH
authors.lastname: Chen
authors.forename: Sheng-Wei
authors.initials: SW
authors.lastname: Lin
authors.forename: Tsui-Ling
authors.initials: TL
authors.lastname: Hsu
authors.forename: Chi-Huey
authors.initials: CH
authors.lastname: Wong
mesh_terms: D001798:Blood Proteins; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002449:Cell Aggregation; D045744:Cell Line, Tumor; D005260:Female; D037483:Galectin 1 / Q000378:metabolism*; D037502:Galectin 3 / Q000378:metabolism*; D037161:Galectins; D006801:Humans; D061986:MCF-7 Cells; D009362:Neoplasm Metastasis / Q000473:pathology*; D011485:Protein Binding
chemical_list: D001798:Blood Proteins; D037483:Galectin 1; D037502:Galectin 3; D037161:Galectins; C445499:LGALS1 protein, human; C428445:LGALS3 protein, human