Galectin

About: Galectin is a research topic. Over the lifetime, 2076 publications have been published within this topic receiving 103409 citations. The topic is also known as: IPR001079 & Galectin.

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. Comp...

Fine specificity of domain-I of recombinant tandem-repeat-type galectin-4 from rat gastrointestinal tract (G4-N).

Abstract: Galectins, a family of beta-galactoside-specific endogenous lectins, are involved in regulating diverse activities such as proliferation/apoptosis, cell-cell (matrix) interaction and cell migration. It is presently unclear to what extent the carbohydrate fine specificities of the combining sites of mammalian galectins overlap. To address this issue, we performed an analysis of the carbohydrate-recognition domain (CRD-I) near the N-terminus of recombinant rat galectin-4 (G4-N) by the biotin/avidin-mediated microtitre plate lectin-binding assay with natural glycoproteins (gps)/polysaccharide and by the inhibition of galectin-glycan interactions with a panel of glycosubstances. Among the 35 glycans tested for lectin binding, G4-N reacted best with human blood group ABH precursor gps, and asialo porcine salivary gps, which contain high densities of the blood group Ii determinants Galbeta1-3GalNAc (the mucin-type sugar sequence on the human erythrocyte membrane) and/or GalNAcalpha1-Ser/Thr ( Tn ), whereas this lectin domain reacted weakly or not at all with most sialylated gps. Among the oligosaccharides tested by the inhibition assay, Galbeta1-3GlcNAcbeta1-3Galbeta1-4Glc was the best. It was 666.7 and 33.3 times more potent than Gal and Galbeta1-3GlcNAc, respectively. G4-N has a preference for the beta-anomer of Gal at the non-reducing ends of oligosaccharides with a Galbeta1-3 linkage, over Galbeta1-4 and Galbeta1-6. The fraction of Tn glycopeptide from asialo ovine submandibular glycoprotein was 8.3 times more active than Galbeta1-3GlcNAc. The overall carbohydrate specificity of G4-N can be defined as Galbeta1-3GlcNAcbeta1-3Galbeta1-4Glc (lacto- N -tetraose)>Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc (lacto- N -neo-tetraose) and Tn clusters>Galbeta1-4Glc and GalNAcbeta1-3Gal>Galbeta1-3GalNAc>Galbeta1-3GlcNAc>Galbeta1-4GlcNAc>GalNAc>Gal. The definition of this binding profile provides the basis to detect differential binding properties relative to the other galectins with ensuing implications for functional analysis.

Galectin-4 Reduces Migration and Metastasis Formation of Pancreatic Cancer Cells

Abstract: Galectin-4 (Gal-4) is a member of the galectin family of glycan binding proteins that shows a significantly higher expression in cystic tumors of the human pancreas and in pancreatic adenocarcinomas compared to normal pancreas. However, the putative function of Gal-4 in tumor progression of pancreatic cancer is still incompletely understood. In this study the role of Gal-4 in cancer progression was investigated, using a set of defined pancreatic cancer cell lines, Pa-Tu-8988S (PaTu-S) and Pa-Tu-8988T (PaTu-T), as a model. These two cell lines are derived from the same liver metastasis of a human primary pancreatic adenocarcinoma, but differ in their growth characteristics and metastatic capacity. We demonstrated that Gal-4 expression is high in PaTu-S, which shows poor migratory properties, whereas much lower Gal-4 levels are observed in the highly metastatic cell line PaTu-T. In PaTu-S, Gal-4 is found in the cytoplasm, but it is also secreted and accumulates at the membrane at sites of contact with neighboring cells. Moreover, we show that Gal-4 inhibits metastasis formation by delaying migration of pancreatic cancer cells in vitro using a scratch assay, and in vivo using zebrafish (Danio rerio) as an experimental model. Our data suggest that Gal-4 may act at the cell-surface of PaTu-S as an adhesion molecule to prevent release of the tumor cells, but has in addition a cytosolic function by inhibiting migration via a yet unknown mechanism.

Galectin-9, a novel prognostic factor with antimetastatic potential in breast cancer.

Abstract: Galectin-9, a member of the beta-galactoside-binding animal lectin family, is involved in various cellular biological events, including aggregation and apoptosis, adhesion of cancer cells, and dendritic cell maturation. We recently reported the relationship between galectin-9 expression in tumor tissue and distant metastasis in breast cancer. Tumors in 42 of the 84 patients were galectin-9-positive, and tumors in 19 of the 21 patients with distant metastasis were galectin-9-negative, assessed by immunohistochemistry. The cumulative distant metastasis-free survival ratio for galectin-9-positive patients was better than for the galectin-9-negative group (p < 0.0001). Multivariate analysis revealed that galectin-9 status influenced distant metastasis independent of and much more than lymph node metastasis. MCF-7 subclones with a high level of galectin-9 expression formed tight clusters during proliferation in vitro, whereas a subclone (K10) with the lowest level of galectin-9 expression did not. However, K10 cells stably transfected with a galectin-9 expression vector aggregated in nude mice as well as in culture. Ectopic expression of galectin-9 also reduced MCF-7 cell adhesion to extracellular matrix proteins.