Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Galectins”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1999

Galectin fingerprinting in tumor diagnosis. Differential expression of galectin-3 and galectin-3 binding sites, but not galectin-1, in benign vs malignant uterine smooth muscle tumors.

Cell-matrix interactions are governed by a distinct set of proteins, with 2 nonintegrin laminin-binding proteins, galectin-1 and galectin-3, providing 1 aspect. The expression patterns of laminin and the 2 galectins and galectin binding sites were quantitatively determined by means of computer-assisted microscopy with the aim of differentiating between 16 leiomyomas and 10 leiomyosarcomas of the uterus. Three quantitative variables were computed for each of the 5 histochemical markers: labeling index, which describes the percentage of tissue area specifically stained by a given marker; mean optical density which reflects the concentration of the marker; and concentrational heterogeneity, which characterizes the degree of heterogeneity of the marker distribution in the tumor tissue areas. The results reveal evident differences in the galectin-3-related parameters in the 2 tumors groups. Whereas the concentration of galectin-3 binding sites was significantly (P = .01) weaker in the leiomyosarcomas than in the leiomyomas, the percentages of tumor tissue expressing galectin-3 (P = .02) and its binding sites (P = .002) were significantly higher in the leiomyosarcomas than in the leiomyomas. Although significantly (P = .02) higher, the concentration of laminin was more heterogeneously distributed (P = .01) in the leiomyosarcomas than in the leiomyomas. In contrast, the levels of expression of galectin-1 and its accessible binding sites remained similar for both the leiomyomas and the leiomyosarcomas. Finally we document how the levels of expression of galectin-3 and its binding sites can be of assistance in reliably differentiating leiomyomas from leiomyosarcomas.

Adult↗
PubMed2004

Thermodynamic binding studies of bivalent oligosaccharides to galectin-1, galectin-3, and the carbohydrate recognition domain of galectin-3.

Galectins are a growing family of animal lectins with common consensus sequences that bind beta-Gal and LacNAc residues. There are at present 14 members of the galectin family; however, certain galectins possess different structures as well as biological properties. Galectin-1 is a dimer of two homologous carbohydrate recognition domains (CRDs) and possesses apoptotic and proinvasive activities. Galectin-3 consists of a C-terminal CRD and an N-terminal nonlectin domain implicated in the oligomerization of the protein and is often associated with antiapoptotic activity. Because many cellular oligosaccharide receptors are multivalent, it is important to characterize the interactions of multivalent carbohydrates with galectins-1 and -3. In the present study, binding of bovine heart galectin-1 and recombinant murine galectin-3 to a series of synthetic analogs containing two LacNAc residues separated by a varying number of methylene groups, as well as biantennary analogs possessing two LacNAc residues, were examined using isothermal titration microcalorimetry (ITC) and hemagglutination inhibition measurements. The thermodynamics of binding of the multivalent carbohydrates to the C-terminal CRD domain of galectin-3 was also investigated. ITC results showed that each bivalent analog bound by both LacNAc residues to the two galectins. However, galectin-1 shows a lack of enhanced affinity for the bivalent straight chain and branched chain analogs, whereas galectin-3 shows enhanced affinity for only lacto-N-hexaose, a naturally occurring branched chain carbohydrate. The CRD domain of galectin-3 was shown to possess similar thermodynamic binding properties as the intact molecule. The results of this study have important implications for the design of carbohydrate inhibitors of the two galectins.

Binding Sites↗
PubMed2006

Role of the carbohydrate recognition domains of mouse galectin-4 in oligosaccharide binding and epitope recognition and expression of galectin-4 and galectin-6 in mouse cells and tissues.

Galectin-4 and its homologue galectin-6 are members of the tandem-repeat subfamily of monomer divalent galectins. Expression of mouse galectin-4 and galectin-6 by RT-PCR using primers designed to distinguish both galectin transcripts indicates that both are expressed in the small intestine, colon, liver, kidney, spleen and heart and P19X1 cells while only galectin-4 is expressed in BW-5147 and 3T3 cell lines. In situ hybridization confirmed the presence of galectin-4/-6 transcripts in the liver and small intestine. Galectin-4 is expressed in spermatozoons and oocytes and its expression during early mouse emryogenesis appears in 8-cell embryos and remains in later stages, as tested by RT-PCR. To study the role of carbohydrate recognition domains (CRDs) in oligosaccharide binding and epitope recognition, we cloned mouse full-length galectin-4 and galectin-6 cDNA and constructed bacterial expression vectors producing histidin-tagged recombinant galectin-4 and its truncated CRD1 and CRD2 forms. Oligosaccharide binding profile for all recombinant forms was assessed using Glycan Array available through the Consortium for Functional Glycomics. Acquired data indicate that mGalectin-4 binds to alpha-GalNAc and alpha-Gal A and B type structures with or without fucose. While the CRD2 domain has a high specificity and affinity for A type-2 alpha-GalNAc structures, the CRD1 domain has a broader specificity in correlation to the total binding profile. These data suggest that CRD2 might be the dominant binding domain of mouse galectin-4. Mapping of epitopes reactive for biotinylated his-tagged CRD1, CRD2 and mGalectin-4 performed on mouse cryosections showed that all three forms bind to alveolar macrophages, macrophages of red pulp of the spleen and proximal tubuli of the kidney and this binding was inhibited by 5 mM lactose. Interestingly, mGalectin-4, but not CRD forms, binds to the suprabasal layer of squamous epithelium of the tongue, suggesting that the link region also plays an important role in ligand recognition.

3T3 Cells↗
PubMed2001

The levels of expression of galectin-3, but not of galectin-1 and galectin-8, correlate with apoptosis in human cholesteatomas.

OBJECTIVES: To investigate whether galectins 1, 3, and 8 are expressed in human cholesteatomas and whether any such expression does correlate with the level of apoptosis, which is, as we have previously shown, predictive of recurrence.7 STUDY DESIGN: The analysis of 52 cholesteatomas resected by the same surgeon by means of canal wall up and canal wall down procedures. METHODS: The immunohistochemical levels of expression of galectins 1, 3, and 8 were quantitatively determined (using computer-assisted microscopy) on conventional histological slides by means of specific anti-galectin-1, anti-galectin-3, and anti-galectin-8 antibodies. The level of apoptosis in each cholesteatoma under study had already been determined 7 by means of the in situ labeling of nuclear DNA fragmentation (Tolt-mediated dUTP nick end labeling [TUNEL] staining). RESULTS: Galectin-1 was expressed markedly in both the epithelial and the connective tissue areas of all the cholesteatomas under study. The levels of expression of galectin-3 and galectin-8 were considerably lower than that of galectin-1. The level of expression of galectin-3 correlated both highly and positively with the level of apoptosis. CONCLUSIONS: An upregulation of galectin-3 (known to have an antiapoptotic and antianoikis effect in certain model systems) expression, which is associated with pronounced apoptotic activity, could have a physiologically protective effect against the characteristically substantial apoptotic features occurring in recurrent cholesteatomas.

Antigens, Differentiation↗
PubMed1997

Strikingly different localization of galectin-3 and galectin-4 in human colon adenocarcinoma T84 cells. Galectin-4 is localized at sites of cell adhesion.

Two beta-galactoside-binding proteins were found to be prominently expressed in the human colon adenocarcinoma T84 cell line. Cloning and sequencing of one, a 36-kDa protein, identified it as the human homolog of galectin-4, a protein containing two carbohydrate binding domains and previously found only in the epithelial cells of the rat and porcine alimentary tract. The other, a 29-kDa protein, is galectin-3, containing a single carbohydrate binding domain, previously found in a number of different cell types including human intestinal epithelium. Despite the marked similarities in the carbohydrate binding domains of these two galectins, their cellular distribution patterns are strikingly different and vary with cellular conditions. In confluent T84 cells, galectin-4 is mostly cytosolic and concentrated at the basal membrane, whereas galectin-3 tends to be concentrated in large granular inclusions mostly at the apical membrane. In subconfluent T84 cells, each galectin is distributed to specific domains of lamellipodia, with galectin-4 concentrated in the leading edge and galectin-3 more proximally. Such different localization of galectins-4 and -3 within T84 cells implies different targeting mechanisms, ligands, and functions. The localization of galectin-4 suggests a role in cell adhesion which is also supported by the ability of immobilized recombinant galectin-4 to stimulate adhesion of T84 cells.

Adenocarcinoma↗
PubMed1998

Production and characterization of a monoclonal antibody able to discriminate galectin-1 from galectin-2 and galectin-3.

Antisera raised against galectin-1 exhibit crossreactivities with other galectins or related molecules. In order to overcome this problem, a monoclonal antibody to human brain galectin-1 was obtained by selecting clones without reactivity toward galectin-3. This mAb specifically bound galectin-1 of various animal origins but neither galectin-2 nor galectin-3. Western-blotting analysis of soluble human brain extracts after 2D gel electrophoresis revealed only the two most acidic isoforms of galectin-1. The ability of this mAb to bind galectin-1/asialofetuin complexes indicates that its epitope is not localized in the carbohydrate recognition domain of galectin-1. This particularity induces with efficiency its monospecificity.

Amino Acid Sequence↗
PubMed2004

Dual activities of galectin-3 in human prostate cancer: tumor suppression of nuclear galectin-3 vs tumor promotion of cytoplasmic galectin-3.

Galectin-3, a multifunctional lectin, is involved during cancer progression. Previous observations showed that both cytosolic expression and nuclear exclusion of galectin-3 in human prostate cancer cells were associated to progression of the disease. In this study, we examined the biological roles of galectin-3 when expressed either in the nucleus or in the cytosol. LNCaP, a galectin-3-negative human prostate cancer cell line, was used to generate transfectants expressing galectin-3 either in the nucleus or in the cytosol. No changes in cell morphology, proliferation, attachment to laminin-1 or androgen dependency were observed. Cytoplasmic galectin-3 induced significantly increased Matrigel invasion, anchorage-independent growth and in vivo tumor growth and angiogenesis, and decreased inducible apoptosis. Surprisingly, nuclear galectin-3 affected these parameters in an opposite fashion with an overall antitumoral activity. Thus, our study demonstrates that galectin-3 exerts opposite biological activities according to its cellular localization: nuclear galectin-3 plays antitumor functions and cytoplasmic galectin-3 promotes tumor progression.

Androgens↗
PubMed1999

Differential expression of endogenous galectin-1 and galectin-3 in human prostate cancer cell lines and effects of overexpressing galectin-1 on cell phenotype.

We have analyzed the expression of galectin-1 and galectin-3 in four human prostate carcinoma cell lines. Northern analysis and immunoblotting experiments showed that three cell lines express both galectins. However, only galectin-1 was detected on the surface of these cells. The LNCaP line expressed neither galectin. LNCaP was transfected with galectin-1 and four clones were isolated, all of which expressed galectin-1 on the cell surface. Kinetics of binding to extracellular matrix proteins appeared to be accelerated in the transfected lines, but overall binding was not enhanced. When the same experiments were performed in the presence of EDTA to eliminate the effects of integrins, binding of a galectin-1 clone to laminin and fibronectin was increased relative to the control cell line. We propose that galectins may contribute to the adhesive properties of some prostate cancer cells.

Antigens, Differentiation↗
PubMed2007

Carbohydrate-recognition domains of galectin-9 are involved in intermolecular interaction with galectin-9 itself and other members of the galectin family.

Galectin-9 (Gal-9) is a tandem-repeat-type member of the galectin family associated with diverse biological processes, such as apoptosis, cell aggregation, and eosinophil chemoattraction. Although the detailed sugar-binding specificity of Gal-9 has been elucidated, molecular mechanisms that underlie these functions remain to be investigated. During the course of our binding study by affinity chromatography and surface plasmon resonance (SPR) analysis, we found that human Gal-9 interacts with immobilized Gal-9 in the protein-protein interaction mode. Interestingly, this intermolecular interaction strongly depended on the activity of the carbohydrate recognition domain (CRD), because the addition of potent saccharide inhibitors abolished the binding. The presence of multimers was also confirmed by Ferguson plot analysis of result of polyacrylamide gel electrophoresis and matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). Moreover, this intermolecular interaction was observed between Gal-9 and other galectin members, such as Gal-3 and Gal-8, but not Gal-1. Because such properties have not been reported yet, they may explain an unidentified mechanism underlying the diverse functions of Gal-9.

Chromatography, Affinity↗
PubMed1995

Galectin-8. A new rat lectin, related to galectin-4.

A protein of 35 kDa which has the characteristic properties of galectins (S-type lectins) was cloned from rat liver cDNA expression library. Since names for galectins 1-7 were already assigned, this new protein was named galectin-8. Three lines of evidence demonstrate that galectin-8 is indeed a novel galectin: (i) its deduced amino acid sequence contains two domains with conserved motifs that are implicated in the carbohydrate binding of galectins, (ii) in vitro translation products of galectin-8 cDNA or bacterially expressed recombinant galectin-8 are biologically active and possess sugar binding and hemagglutination activity, and (iii) a protein of the expected size (34 kDa) that binds to lactosyl-Sepharose and reacts with galectin-8-specific antibodies is present in rat liver and comprises approximately 0.025% of the total Triton X-100-soluble hepatic proteins. Overall, galectin-8 is structurally related (34% identity) to galectin-4, a soluble rat galectin with two carbohydrate-binding domains in the same polypeptide chain, joined by a link peptide. Nonetheless, several important features distinguish these two galectins: (i) Northern blot analysis revealed that, unlike galectin-4 that is confined to the intestine and stomach, galectin-8 is expressed in liver, kidney, cardiac muscle, lung, and brain; (ii) unlike galectin-4, but similar to galectins-1 and -2, galectin-8 contains 4 Cys residues; (iii) the link peptide of galectin-8 is unique and bears no similarity to any known protein; (iv) the N-terminal carbohydrate-binding region of galectin-8 contains a unique WG-E-I motif instead of the consensus WG-E-R/K motif implicated as playing an essential role in sugar-binding of all galectins. Together with galectin-4, galectin-8 therefore represents a subfamily of galectins consisting of a tandem repeat of structurally different carbohydrate recognition domains within a single polypeptide chain.

Amino Acid Sequence↗
PubMed2006

Galectin-3 and galectin-1 bind distinct cell surface glycoprotein receptors to induce T cell death.

Galectins are a family of mammalian beta-galactoside-binding proteins that positively and negatively regulate T cell death. Extracellular galectin-1 directly induces death of T cells and thymocytes, while intracellular galectin-3 blocks T cell death. In contrast to the antiapoptotic function of intracellular galectin-3, we demonstrate that extracellular galectin-3 directly induces death of human thymocytes and T cells. However, events in galectin-3- and galectin-1-induced cell death differ in a number of ways. Thymocyte subsets demonstrate different susceptibility to the two galectins: whereas galectin-1 kills double-negative and double-positive human thymocytes with equal efficiency, galectin-3 preferentially kills double-negative thymocytes. Galectin-3 binds to a complement of T cell surface glycoprotein receptors distinct from that recognized by galectin-1. Of these glycoprotein receptors, CD45 and CD71, but not CD29 and CD43, appear to be involved in galectin-3-induced T cell death. In addition, CD7 that is required for galectin-1-induced death is not required for death triggered by galectin-3. Following galectin-3 binding, CD45 remains uniformly distributed on the cell surface, in contrast to the CD45 clustering induced by galectin-1. Thus, extracellular galectin-3 and galectin-1 induce death of T cells through distinct cell surface events. However, as galectin-3 and galectin-1 cell death are neither additive nor synergistic, the two death pathways may converge inside the cell.

Antigens, CD↗
PubMed2000

Galectin-1 and galectin-3 in chronic pancreatitis.

Galectin-1 and galectin-3 have important functions in cell-cell interactions, cell adhesion to extracellular matrix, the organization of extracellular matrix, and tissue remodeling. To assess their potential role in chronic pancreatitis (CP), we examined their expression by Northern blot analysis, in situ hybridization, immunohistochemistry, and Western blot analysis in normal and CP pancreatic tissues. Northern blot analysis revealed a 4.5-fold increase of galectin-1 mRNA (p < 0.01) and a 3.8-fold increase of galectin-3 mRNA (p < 0.01) in CP samples compared with normal controls. In situ hybridization analysis of normal pancreas indicated low abundance of galectin-1 mRNA in fibroblasts, whereas galectin-3 mRNA was moderately present in ductal cells. CP samples exhibited moderate to intense galectin-1 mRNA signals in fibroblasts, whereas galectin-3 mRNA signals were intense in the cells of ductular complexes and weak in the degenerating acinar cells. In addition, intense galectin-1 and galectin-3 mRNA signals were present in nerves of normal and CP samples. Immunohistochemistry showed a distribution pattern of galectin-1 and galectin-3 similar to that described for in situ hybridization. Relative quantification of galectin-1 and galectin-3 protein by immunoblotting revealed an increase of 3.2-fold and 3.0-fold, respectively, in CP compared with normal controls. There was a significant correlation between galectin-1 and fibrosis and between galectin-3 and fibrosis and the density of ductular complexes. Up-regulation of galectin-1 in fibroblasts and galectin-3 in ductular complexes suggests a role of these lectins in tissue remodeling in CP. Galectin-1 might participate in ECM changes, whereas galectin-3 seems to be involved in both ECM changes and ductular complex formation.

Adult↗
PubMed1996

The primary structure and carbohydrate specificity of a beta-galactosyl-binding lectin from toad (Bufo arenarum Hensel) ovary reveal closer similarities to the mammalian galectin-1 than to the galectin from the clawed frog Xenopus laevis.

The detailed characterization of a galectin from the toad (Bufo arenarum Hensel) ovary in its primary structure, carbohydrate specificity, and overall biochemical properties has provided novel information pertaining to structural and evolutionary aspects of the galectin family. The lectin consists of identical single-chain polypeptide subunits composed of 134 amino acids (calculated mass, 14,797 daltons), and its N-terminal residue, alanine, is N-acetylated. When compared to the sequences of known galectins, the B. arenarum galectin exhibited the highest identity (48% for the whole molecule and 77% for the carbohydrate recognition domain (CRD)) with the bovine spleen galectin-1, but surprisingly less identity (38% for the whole molecule and 47% for the CRD) with a galectin from Xenopus laevis skin (Marschal, P., Herrmann, J., Leffler, H., Barondes, S. H., and Cooper, D. N. W. (1992) J. Biol. Chem. 267, 12942-12949). Unlike the X. laevis galectin, the binding activity of the B. arenarum galectin for N-acetyllactosamine, the human blood group A tetrasaccharide and Galbeta1,3GalNAc relative to lactose, was in agreement with that observed for the galectin-1 subgroup and those galectins having "conserved" (type I) CRDs (Ahmed, H., and Vasta, G. R. (1994) Glycobiology 4, 545-549). Moreover, the toad galectin shares three of the six cysteine residues that are conserved in all mammalian galectins-1, but not in the galectins from X. laevis, fish, and invertebrates described so far. Based on the homologies of the B. arenarum galectin with the bovine spleen galectin-1 and X. laevis skin galectin, it should be concluded that within the galectin family the correlation between conservation of primary structure and phylogenetic distances among the source species may not be a direct one as proposed elsewhere (Hirabayashi, J., and Kasai, K. (1993) Glycobiology 3, 297-304). Furthermore, galectins with conserved (type I) CRDs, represented by the B. arenarum ovary galectin, and those with "variable" (type II) CRDs, represented by the X. laevis 16-kDa galectin, clearly constitute distinct subgroups in the extant amphibian taxa and may have diverged early in the evolution of chordate lineages.

Amino Acid Sequence↗
PubMedDate not supplied

Galectins-1 and -3 and their ligands in tumor biology. Non-uniform properties in cell-surface presentation and modulation of adhesion to matrix glycoproteins for various tumor cell lines, in biodistribution of free and liposome-bound galectins and in their expression by breast and colorectal carcinomas with/without metastatic propensity.

Protein (lectin)-carbohydrate (cellular glycoconjugate) recognition is operative in biochemical information transfer. Galectins constitute a family of endogenous galactoside-binding lectins with conserved features in the binding site. The members of this lectin category are assumed to be involved in cell adhesion and growth regulation. To assess to what extent the different modes of binding-site presentation and/or carbohydrate fine-specificities will affect aspects of galectin behavior, homodimeric cross-linking galectin-1 and monomeric chimeric galectin-3, with its collagenase-sensitive stalk linked to the carbohydrate-recognition domain, were investigated. Cell-surface expression of the two galectins and accessible galectin-binding sites on various tumor cell lines was ascertained by FACScan analysis. In particular, ligand accessibility for the two galectins differed for the tested cell line types. Binding of tumor cells to laminin and plasma or placental fibronectin was generally reduced by treatment of cells or matrix with galectins. Galectin-3 was more efficient than galectin 1 at impairing laminin's potency as matrix. Cell binding of galectin-1, on the other hand, proved on average more effective for blocking cell association to fibronectins after its preincubation with cell suspensions. Differences were also apparent in the biodistribution of the galectins, where an avian homolog of galectin- served as the control to distinguish effects of spatial and sugar-binding features. Histopathological analysis of lymph-node-negative and -positive breast and colorectal carcinomas (n = 180 including 60 metastatic lesions) indicated a correlation of either increased galectin-1 binding and reduced galectin-3 expression or reduced binding of both galectins with the occurrence of lymph node lesions. Together with data on the heparin-binding lectin, revealing reduced expression to be associated with a positive lymph-node status in the breast cancer group, these results can be interpreted to reflect cell-type-dependent requirements of galectin ligand presentation during the metastatic cascade. By introducing mammalian lectins to lectin-histochemical studies, the detection of quantitative differences in glycosylation brings an understanding of its cell biological significance one step closer.

Adenocarcinoma↗
PubMed2004

Alterations in galectin-3 expression and distribution correlate with breast cancer progression: functional analysis of galectin-3 in breast epithelial-endothelial interactions.

To define the role of galectin-3 in breast cancer progression, we have used a novel three-dimensional co-culture system that recapitulates in vivo reciprocal functional breast epithelial-endothelial cell-cell and cell-matrix interactions, and examined the expression of galectin-3 mRNA and protein in human breast tumors and xenografts. Galectin-3 is required for the stabilization of epithelial-endothelial interaction networks because immunoneutralization with galectin-3 antibodies abolishes the interactions in a dose-dependent manner. Co-culture of epithelial cells with endothelial cells results in increase in levels of secreted galectin-3 and presence of proteolytically processed form of galectin-3 in the conditioned media. In contrast, intracellular galectin-3 predominantly exists in the intact form. This difference in sensitivity to proteolytic processing of secreted versus intracellular galectin-3 probably arises from differences in accessibility of protease-sensitive sites, levels, and/or type of activated protease(s), and may be indicative of different functional roles for intact and processed galectin-3. To determine whether the proteolytically cleaved galectin-3 retains its ability to bind to endothelial cells, binding assays were performed with the full-length and matrix metallopeoteinase-2-cleaved recombinant galectin-3. Although a dose-dependent increase in binding to human umbilical vein endothelial cells was observed with both full-length and cleaved galectin-3, proteolytically cleaved galectin-3 displayed approximately 20-fold higher affinity for human umbilical vein endothelial cells as compared to the full-length protein. Examination of galectin-3 expression in breast tumors and xenografts revealed elevated levels of galectin-3 mRNA and protein in the luminal epithelial cells of normal and benign ducts, down-regulation in early grades of ductal carcinoma in situ (DCIS), and re-expression in peripheral tumor cells as DCIS lesions progressed to comedo-DCIS and invasive carcinomas. These data suggest that galectin-3 expression is associated with specific morphological precursor subtypes of breast cancer and undergoes a transitional shift in expression from luminal to peripheral cells as tumors progressed to comedo-DCIS or invasive carcinomas. Such a localized expression of galectin-3 in cancer cells proximal to the stroma could lead to increased invasive potential by inducing novel or better interactions with the stromal counterparts.

Animals↗
PubMed2003

Carbohydrate binding proteins galectin-1 and galectin-3 in human trabecular meshwork.

PURPOSE: Galectins are a family of carbohydrate binding proteins involved in a variety of biological processes including cell-cell and cell-matrix interactions. We examined galectin-1 and galectin-3 to determine if galectins are expressed in the human trabecular meshwork and Schlemm's canal. METHODS: Human trabecular meshworks were dissected from donor eyes within 12 hr of death. Galectin-1 and galectin-3 expression was examined by RT-PCR and Western blot analysis. Immunohistochemistry of galectin-1 and galectin-3 was analyzed in normal and glaucomatous tissue. RESULTS: Expression of mRNA and protein of Galectin-1 (14 kDa) and galectin-3 (31 kDa) was found in the outflow pathway. Immunostaining revealed galectin-1 and galectin-3 throughout the meshwork, cells lining Schlemm's canal, and extracellular spaces in the inner and outer walls of the canal. Comparison of normal, POAG and PEX samples revealed no difference in location or intensity for either galectin-1 and galectin-3. CONCLUSION: Galectin-1 and galectin-3 are present in human trabecular meshwork of normal and glaucomatous eyes.

Aged↗
PubMed2001

Expression of endogenous galectin-1 and galectin-3 in intrahepatic cholangiocarcinoma.

Galectins, a family of beta-galactoside-binding animal lectins, might be involved in tumor progression. In this study, the expression patterns of galectin-1 and -3 were examined immunohistochemically in intrahepatic cholangiocarcinoma (ICC), with emphasis on its development and progression as well as its histopathologic features, by use of samples of normal intrahepatic bile duct (n = 20), biliary epithelial dysplasia (n = 15), ICC (n = 40), and a cholangiocarcinoma cell line, CCKS1. In normal intrahepatic bile ducts, galectin-3 was constitutively but weakly expressed, whereas galectin-1 was not expressed. In hepatolithiasis, biliary epithelial dysplasia was strongly positive for galectin-3 but negative for galectin-1. Galectin-3 was frequently and strongly expressed in the cytoplasm of well-differentiated ICCs, and its expression was significantly decreased and less intense or even absent in poorly differentiated ICCs. Galectin-1 was expressed in carcinoma cells in ICC, and its incidence and extent were correlated with histologic dedifferentiation of ICC. Proliferative cell nuclear antigen (PCNA) labeling index (LI) was higher in ICC cases positive for galectin-1 than in those that were negative. Galectin-1 was strongly expressed in cancerous stroma of ICC, and this stromal expression was related to histologic dedifferentiation of ICC. In the carcinoma cell line CCKS1, galectin-1 and -3 were expressed in the cytoplasm of carcinoma cells, and galectin-1 was additionally detected in the culture medium. These results suggest that galectin-1 was newly expressed on carcinoma cells of ICC, and its overexpression seems to be associated with neoplastic progression and proliferative activities, and the expression of galectin-1 in cancerous stroma may also be related to the progression of ICC. Galectin-3 expression in epithelial cells is up-regulated in the preneoplastic and early neoplastic stages of ICC, although galectin-3 tends to disappear at later stages of ICC. HUM PATHOL 32:302-310.

Adult↗
PubMed2003

Expression of galectin-1 and galectin-3 in human fetal thyroid gland.

High levels of expression of galectin-1 and galectin-3, the beta-galactoside-binding proteins, have been recently described in malignant thyroid tumors but not in adenomas nor in normal thyroid tissue. However, there are no data about the expression of these galectins during fetal thyroid development. In this study we analyzed immunohistochemically the presence of galectin-1 and galectin-3 in human fetal thyroid glands (16-37 weeks of gestation). Weak to moderate cytoplasmic staining for galectin-1 was observed in follicular cells of all fetal thyroids. Galectin-3 could not be detected in thyroid follicular cells of any fetal thyroid investigated. Both galectins were detected in stromal tissue, but staining for galectin-1 was more intense. The absence of galectin-3 in thyroid cells during fetal development suggests that galectin-3 is expressed de novo during malignant transformation of thyroid epithelium, and that galectin-1 could be considered an oncofetal antigen. The results obtained indicated potential roles for galectin-1 and galectin-3 during the investigated period of human fetal thyroid gland development. Both galectins might participate in developmental processes regarding stromal fetal thyroid tissue organization, whereas galectin-1 might have a function in thyroid epithelium maturation.

Galectin 1↗