1
|
Berois N, Pittini A, Osinaga E. Targeting Tumor Glycans for Cancer Therapy: Successes, Limitations, and Perspectives. Cancers (Basel) 2022; 14:cancers14030645. [PMID: 35158915 PMCID: PMC8833780 DOI: 10.3390/cancers14030645] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/17/2022] [Accepted: 01/21/2022] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Aberrant glycosylation is a common feature of many cancers, and it plays crucial roles in tumor development and biology. Cancer progression can be regulated by several physiopathological processes controlled by glycosylation, such as cell–cell adhesion, cell–matrix interaction, epithelial-to-mesenchymal transition, tumor proliferation, invasion, and metastasis. Different mechanisms of aberrant glycosylation lead to the formation of tumor-associated carbohydrate antigens (TACAs), which are suitable for selective cancer targeting, as well as novel antitumor immunotherapy approaches. This review summarizes the strategies developed in cancer immunotherapy targeting TACAs, analyzing molecular and cellular mechanisms and state-of-the-art methods in clinical oncology. Abstract Aberrant glycosylation is a hallmark of cancer and can lead to changes that influence tumor behavior. Glycans can serve as a source of novel clinical biomarker developments, providing a set of specific targets for therapeutic intervention. Different mechanisms of aberrant glycosylation lead to the formation of tumor-associated carbohydrate antigens (TACAs) suitable for selective cancer-targeting therapy. The best characterized TACAs are truncated O-glycans (Tn, TF, and sialyl-Tn antigens), gangliosides (GD2, GD3, GM2, GM3, fucosyl-GM1), globo-serie glycans (Globo-H, SSEA-3, SSEA-4), Lewis antigens, and polysialic acid. In this review, we analyze strategies for cancer immunotherapy targeting TACAs, including different antibody developments, the production of vaccines, and the generation of CAR-T cells. Some approaches have been approved for clinical use, such as anti-GD2 antibodies. Moreover, in terms of the antitumor mechanisms against different TACAs, we show results of selected clinical trials, considering the horizons that have opened up as a result of recent developments in technologies used for cancer control.
Collapse
Affiliation(s)
- Nora Berois
- Laboratorio de Glicobiología e Inmunología Tumoral, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay;
- Correspondence: (N.B.); (E.O.)
| | - Alvaro Pittini
- Laboratorio de Glicobiología e Inmunología Tumoral, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay;
- Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay
| | - Eduardo Osinaga
- Laboratorio de Glicobiología e Inmunología Tumoral, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay;
- Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay
- Correspondence: (N.B.); (E.O.)
| |
Collapse
|
2
|
Lieshchova MA, Bohomaz AA, Brygadyrenko VV. Effect of Salvia officinalis and S. sclarea on rats with a high-fat hypercaloric diet. REGULATORY MECHANISMS IN BIOSYSTEMS 2021. [DOI: 10.15421/022176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phytotherapy for the correction of excess body weight is widely used. However, a comprehensive study of herbal preparations on the organism of model animals has been carried out only for a few plant species. Supplementing the diet of rats with closely related sage species (Salvia officinalis L. and S. sclarea L.) against the background of high-fat hypercaloric diet triggered multidirectional changes in their metabolism. The addition of crushed dry shoots of S. officinalis to the diet of animals led to a sharp increase in their body weight (up to 130.8% of the initial one in 30 days of the experiment). The body weight of the rats treated with S. sclarea for 30 days increased only up to 103.8% of their initial weight and was lower than in the control group. Addition of S. officinalis caused an increase in daily weight gain up to 253.1% of the control group, and S. sclarea – its decrease to 27.8% of the daily weight gain in the control group. In the S. officinalis group, the relative weight of the brain, spleen, and thymus decreased, while in the S. sclarea group, the relative weight of the thymus decreased and that of the colon increased. Under the influence of S. officinalis, the concentration of urea, total bilirubin, and triglycerides in the blood plasma of male rats decreased and the concentration of total protein and the activity of alkaline phosphatase increased. While consuming S. sclarea shoots, there was an increase of alkaline phosphatase activity in the rats’ blood, but atherogenic index (23.1% of the level of the control group) sharply dropped due to an increase in the concentration of high-density lipoprotein cholesterol (286.9% of the control) and a decrease in the concentration of low-density lipoprotein cholesterol (67.7% of control). In rats feeding on S. sclarea shoots, we observed a decrease in the concentration of triglycerides in the blood (39.9% of the control), a decrease in the activity of gamma-glutamyl transferase (62.8%), and an increase in the Ca/P ratio (132.5% of the control group). No significant changes were observed in CBC and WBC differential of male rats when eating S. officinalis and S. sclarea shoots. According to the results of the open field test, the physical and orientational activity of male rats under the influence of S. officinalis significantly decreased by the end of the experiment. Emotional status of rats, on the contrary, decreased when they ate dry crushed shoots of S. sclarea in the composition of the food. Thus, excess body weight of rats in the conditions of hypercaloric diet led to more pronounced deviations from the norm while consuming dry crushed shoots of S. officinalis. The addition of S. sclarea dry crushed shoots to the animals’ diet normalized the body weight in comparison with the control group, reduced the negative manifestations of obesity at the biochemical and organismal levels. In this regard, the substances that contains S. sclarea should be carefully studied for anti-atherosclerotic activity, and tea supplemented with S. sclarea shoots can be recommended as a corrective supplement in the diet of overweight people.
Collapse
|
3
|
Poiroux G, Barre A, van Damme EJM, Benoist H, Rougé P. Plant Lectins Targeting O-Glycans at the Cell Surface as Tools for Cancer Diagnosis, Prognosis and Therapy. Int J Mol Sci 2017; 18:ijms18061232. [PMID: 28598369 PMCID: PMC5486055 DOI: 10.3390/ijms18061232] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/26/2017] [Accepted: 05/31/2017] [Indexed: 12/30/2022] Open
Abstract
Aberrant O-glycans expressed at the surface of cancer cells consist of membrane-tethered glycoproteins (T and Tn antigens) and glycolipids (Lewis a, Lewis x and Forssman antigens). All of these O-glycans have been identified as glyco-markers of interest for the diagnosis and the prognosis of cancer diseases. These epitopes are specifically detected using T/Tn-specific lectins isolated from various plants such as jacalin from Artocarpus integrifola, and fungi such as the Agaricus bisporus lectin. These lectins accommodate T/Tn antigens at the monosaccharide-binding site; residues located in the surrounding extended binding-site of the lectins often participate in the binding of more extended epitopes. Depending on the shape and size of the extended carbohydrate-binding site, their fine sugar-binding specificity towards complex O-glycans readily differs from one lectin to another, resulting in a great diversity in their sugar-recognition capacity. T/Tn-specific lectins have been extensively used for the histochemical detection of cancer cells in biopsies and for the follow up of the cancer progression and evolution. T/Tn-specific lectins also induce a caspase-dependent apoptosis in cancer cells, often associated with a more or less severe inhibition of proliferation. Moreover, they provide another potential source of molecules adapted to the building of photosensitizer-conjugates allowing a specific targeting to cancer cells, for the photodynamic treatment of tumors.
Collapse
Affiliation(s)
- Guillaume Poiroux
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche, Centre de Recherche en Cancérologie de Toulouse, 31037 Toulouse, France.
| | - Annick Barre
- Unité Mixte de Recherche, 152 PharmaDev, Institut de Recherche et Développement, Faculté de Pharmacie, 35 Chemin des Maraîchers Université Paul Sabatier, 31062 Toulouse, France.
| | - Els J M van Damme
- Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
| | - Hervé Benoist
- Unité Mixte de Recherche, 152 PharmaDev, Institut de Recherche et Développement, Faculté de Pharmacie, 35 Chemin des Maraîchers Université Paul Sabatier, 31062 Toulouse, France.
| | - Pierre Rougé
- Unité Mixte de Recherche, 152 PharmaDev, Institut de Recherche et Développement, Faculté de Pharmacie, 35 Chemin des Maraîchers Université Paul Sabatier, 31062 Toulouse, France.
| |
Collapse
|
4
|
O-glycosylation of NnTreg lymphocytes recognized by the Amaranthus leucocarpus lectin. Clin Dev Immunol 2013; 2013:506807. [PMID: 24174970 PMCID: PMC3794550 DOI: 10.1155/2013/506807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 08/04/2013] [Indexed: 12/17/2022]
Abstract
O-glycosidically-linked glycans have been involved in development, maturation, homing, and immune regulation in T cells. Previous reports indicate that Amaranthus leucocarpus lectin (ALL), specific for glycans containing galactose-N-acetylgalactosamine and N-acetylgalactosamine, recognizes human naïve CD27+CD25+CD4+ T cells. Our aim was to evaluate the phenotype of CD4+ T cells recognized by ALL in peripheral blood mononuclear cells obtained from healthy volunteers. CD4+ T cells were isolated by negative selection using magnetic beads-labeled monoclonal antibodies; the expression of T regulatory cell phenotypic markers was assessed on ALL-recognized cells. In addition, IL-4, IL-10, IFN-γ, and TGF-β intracellular production in ALL+ cells was also evaluated. The analyses of phenotypic markers and intracellular cytokines were performed through flow cytometry. ALL-recognized CD4+ T cells were mainly CD45RA+, CCR7+ cells. Although 52 ± 10% CD25+Foxp3+ cells were positive to ALL, only 34 ± 4% of ALL+ cells corresponded to CD25+Foxp3− cells. Intracellular cytokines in freshly obtained ALL+CD4+ T cells exhibited 8% of IL-4, 15% of IL-10, 2% of IFN-γ, and 15% of TGF-β, whereas ALL−CD4+ T cells depicted 1% of IL-4, 2% of IL-10, <1% of IFN-γ, and 6% of TGF-β. Our results show that galactose-N-acetylgalactosamine and N-galactosamine-bearing CD4+ T cells expressed phenotypic markers of NnTreg cells.
Collapse
|
5
|
Mazal D, Lo-Man R, Bay S, Pritsch O, Dériaud E, Ganneau C, Medeiros A, Ubillos L, Obal G, Berois N, Bollati-Fogolin M, Leclerc C, Osinaga E. Monoclonal antibodies toward different Tn-amino acid backbones display distinct recognition patterns on human cancer cells. Implications for effective immuno-targeting of cancer. Cancer Immunol Immunother 2013; 62:1107-22. [PMID: 23604173 PMCID: PMC11029704 DOI: 10.1007/s00262-013-1425-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 03/31/2013] [Indexed: 02/06/2023]
Abstract
The Tn antigen (GalNAcα-O-Ser/Thr) is a well-established tumor-associated marker which represents a good target for the design of anti-tumor vaccines. Several studies have established that the binding of some anti-Tn antibodies could be affected by the density of Tn determinant or/and by the amino acid residues neighboring O-glycosylation sites. In the present study, using synthetic Tn-based vaccines, we have generated a panel of anti-Tn monoclonal antibodies. Analysis of their binding to various synthetic glycopeptides, modifying the amino acid carrier of the GalNAc(*) (Ser* vs Thr*), showed subtle differences in their fine specificities. We found that the recognition of these glycopeptides by some of these MAbs was strongly affected by the Tn backbone, such as a S*S*S* specific MAb (15G9) which failed to recognize a S*T*T* or a T*T*T* structure. Different binding patterns of these antibodies were also observed in FACS and Western blot analysis using three human cancer cell lines (MCF-7, LS174T and Jurkat). Importantly, an immunohistochemical analysis of human tumors (72 breast cancer and 44 colon cancer) showed the existence of different recognition profiles among the five antibodies evaluated, demonstrating that the aglyconic part of the Tn structure (Ser vs Thr) plays a key role in the anti-Tn specificity for breast and colon cancer detection. This new structural feature of the Tn antigen could be of important clinical value, notably due to the increasing interest of this antigen in anticancer vaccine design as well as for the development of anti-Tn antibodies for in vivo diagnostic and therapeutic strategies.
Collapse
MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/metabolism
- Antibody Specificity/immunology
- Antigens, Tumor-Associated, Carbohydrate/chemistry
- Antigens, Tumor-Associated, Carbohydrate/immunology
- Antigens, Tumor-Associated, Carbohydrate/metabolism
- Biomarkers, Tumor
- Breast Neoplasms/immunology
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cell Line, Tumor
- Colonic Neoplasms/immunology
- Colonic Neoplasms/metabolism
- Colonic Neoplasms/pathology
- Female
- Glycopeptides/chemistry
- Glycopeptides/immunology
- Glycopeptides/metabolism
- Humans
- Male
- Mice
- Middle Aged
- Neoplasm Staging
- Neoplasms/immunology
- Neoplasms/metabolism
- Neoplasms/pathology
- Protein Binding/immunology
Collapse
Affiliation(s)
- Daniel Mazal
- Departamento de Anatomía Patológica y Citología del Hospital de la Mujer, Centro Hospitalario Pereira Rossell, Montevideo, Uruguay
| | - Richard Lo-Man
- Unité de Régulation Immunitaire et Vaccinologie, Institut Pasteur, Paris, France
- Institut National de la Santé et de la Recherche Médicale, U1041 Paris, France
| | - Sylvie Bay
- Unité de Chimie des Biomolécules, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR 3523, Paris, France
| | - Otto Pritsch
- Departamento de Inmunobiologia, Facultad de Medicina, Universidad de la República, Avda Gral Flores 2125, 11800 Montevideo, Uruguay
- Unidad de Biofísica de Proteínas, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Edith Dériaud
- Unité de Régulation Immunitaire et Vaccinologie, Institut Pasteur, Paris, France
- Institut National de la Santé et de la Recherche Médicale, U1041 Paris, France
| | - Christelle Ganneau
- Unité de Chimie des Biomolécules, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR 3523, Paris, France
| | - Andrea Medeiros
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Luis Ubillos
- Departamento de Inmunobiologia, Facultad de Medicina, Universidad de la República, Avda Gral Flores 2125, 11800 Montevideo, Uruguay
| | - Gonzalo Obal
- Departamento de Inmunobiologia, Facultad de Medicina, Universidad de la República, Avda Gral Flores 2125, 11800 Montevideo, Uruguay
- Unidad de Biofísica de Proteínas, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Nora Berois
- Laboratorio de Glicobiología e Inmunología Tumoral, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | | | - Claude Leclerc
- Unité de Régulation Immunitaire et Vaccinologie, Institut Pasteur, Paris, France
- Institut National de la Santé et de la Recherche Médicale, U1041 Paris, France
| | - Eduardo Osinaga
- Departamento de Inmunobiologia, Facultad de Medicina, Universidad de la República, Avda Gral Flores 2125, 11800 Montevideo, Uruguay
- Laboratorio de Glicobiología e Inmunología Tumoral, Institut Pasteur de Montevideo, Montevideo, Uruguay
| |
Collapse
|
6
|
Medeiros A, Berois N, Incerti M, Bay S, Franco Fraguas L, Osinaga E. A Tn antigen binding lectin from Myrsine coriacea displays toxicity in human cancer cell lines. J Nat Med 2012; 67:247-54. [PMID: 22645079 DOI: 10.1007/s11418-012-0671-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 04/11/2012] [Indexed: 02/06/2023]
Abstract
The Tn antigen (GalNAc-O-Ser/Thr) is one of the most specific human cancer-associated structures. In the present study we characterize the biochemical and functional properties of the Myrsine coriacea lectin (McL). We show that McL is an unusual high molecular weight highly glycosylated protein, which displays a strong Tn binding activity. The lectin exhibits in vitro inhibition of proliferation in the six cancer cell lines evaluated, in a dose-dependent manner (the strongest activity being against HT-29 and HeLa cells), whereas it does not exhibit toxicity against normal lymphocytes. McL could be exploited in the design of potential new tools for the diagnosis or treatment of cancer.
Collapse
Affiliation(s)
- Andrea Medeiros
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, 11800, Montevideo, Uruguay
| | | | | | | | | | | |
Collapse
|
7
|
Zhang Y, Li Q, Rodriguez LG, Gildersleeve JC. An array-based method to identify multivalent inhibitors. J Am Chem Soc 2010; 132:9653-62. [PMID: 20583754 PMCID: PMC2923827 DOI: 10.1021/ja100608w] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Carbohydrate-protein interactions play a critical role in a variety of biological processes, and agonists/antagonists of these interactions are useful as biological probes and therapeutic agents. Most carbohydrate-binding proteins achieve tight binding through formation of a multivalent complex. Therefore, both ligand structure and presentation contribute to recognition. Since there are many potential combinations of structure, spacing, and orientation to consider and the optimal one cannot be predicted, high-throughput approaches for analyzing carbohydrate-protein interactions and designing inhibitors are appealing. In this report, we develop a strategy to vary neoglycoprotein density on a surface of a glycan array. This feature of presentation was combined with variations in glycan structure and glycan density to produce an array with approximately 600 combinations of glycan structure and presentation. The unique array platform allows one to distinguish between different types of multivalent complexes on the array surface. To illustrate the advantages of this format, it was used to rapidly identify multivalent probes for various lectins. The new array was first tested with several plant lectins, including concanavalin A (conA), Vicia villosa isolectin B4 (VVL-B(4)), and Ricinus communis agglutinin (RCA120). Next, it was used to rapidly identify potent multivalent inhibitors of Pseudomonas aeruginosa lectin I (PA-IL), a key protein involved in opportunistic infections of P. aeruginosa , and mouse macrophage galactose-type lectin (mMGL-2), a protein expressed on antigen presenting cells that may be useful as a vaccine targeting receptor. An advantage of the approach is that structural information about the lectin/receptor is not required to obtain a multivalent inhibitor/probe.
Collapse
Affiliation(s)
- Yalong Zhang
- Chemical Biology Laboratory, National Cancer Institute, 376 Boyles Street, Building 376, Frederick, Maryland, 21702
| | - Qian Li
- Chemical Biology Laboratory, National Cancer Institute, 376 Boyles Street, Building 376, Frederick, Maryland, 21702
| | - Luis G. Rodriguez
- Optical Microscopy and Analysis Laboratory, SAIC-Frederick, Inc., Advanced Technology Program, NCI-Frederick, Frederick, Maryland, 21702
| | - Jeffrey C. Gildersleeve
- Chemical Biology Laboratory, National Cancer Institute, 376 Boyles Street, Building 376, Frederick, Maryland, 21702
| |
Collapse
|
8
|
Robles A, Medeiros A, Berois N, Balter HS, Pauwels EK, Osinaga E. In-site interaction evaluation of Tn density by inhibition/competition assays. Nucl Med Biol 2010; 37:453-8. [PMID: 20447557 DOI: 10.1016/j.nucmedbio.2009.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 10/29/2009] [Accepted: 10/31/2009] [Indexed: 10/19/2022]
Abstract
The tumor-associated structure N-acetyl-galactosamine-O-Ser/Thr (Tn antigen), which is overexpressed in various tumor cell types, notably of the breast, ovary and colon, is an interesting determinant that is useful for cancer diagnosis and follow-up. The aim of this research was to study different assay strategies in order to determine the most sensitive system for further application in epitope characterization and binding assessment. The tetrameric isolectin obtained from Vicia villosa seeds (VVLB(4)) shows high affinity for the tumor-associated structure. A monoclonal antibody against VVLB(4), MabVV(34), was generated, and the interaction between MabVV(34) and VVLB(4) was studied by means of binding and inhibition assays. Several synthetic peptides (10 amino acid sequences) designed from the amino acid sequence of VVLB(4) and obtained from trypsin digestion were tested to determine which amino acids were involved in the interaction between MabVV(34) and VVLB(4). The further unraveling of this epitope was investigated by inhibition using designed synthetic peptides as well as mixtures mimicking variable density effect. Under the experimental circumstances, MabVV(34) was able to inhibit the binding of VVLB(4) to Tn. Two of the four peptide sequences assayed showed better inhibition properties. Finally, mixtures containing these selected sequences allowed the evaluation of binding and inhibition as a function of Tn density. We conclude that the present study facilitates the further development of a specific Tn marker and may contribute to the development of Tn-like radiolabelled peptides or Tn-specific radiolabelled fragments providing a highly selective tool for cancer diagnosis and treatment. This strategy may contribute to characterize the new generation of radiopharmaceuticals for diagnosis and therapy based on biomolecules like antibodies, fragments or peptides, whose application is directly guided by their specific molecular recognition.
Collapse
Affiliation(s)
- Ana Robles
- Radiopharmacy Department, Nuclear Research Center, Faculty of Sciences, University of the Republic, Montevideo, Uruguay.
| | | | | | | | | | | |
Collapse
|
9
|
Oyelaran O, Li Q, Farnsworth D, Gildersleeve JC. Microarrays with varying carbohydrate density reveal distinct subpopulations of serum antibodies. J Proteome Res 2009; 8:3529-38. [PMID: 19366269 DOI: 10.1021/pr9002245] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Antigen arrays have become important tools for profiling complex mixtures of proteins such as serum antibodies. These arrays can be used to better understand immune responses, discover new biomarkers, and guide the development of vaccines. Nevertheless, they are not perfect and improved array designs would enhance the information derived from this technology. In this study, we describe and evaluate a strategy for varying antigen density on an array and then use the array to study binding of lectins, monoclonal antibodies, and serum antibodies. To vary density, neoglycoproteins containing differing amounts of carbohydrate were synthesized and used to make a carbohydrate microarray with variations in both structure and density. We demonstrate that this method provides variations in density on the array surface within a range that is relevant for biological recognition events. The array was used to evaluate density dependent binding properties of three lectins (Vicia villosa lectin B4, Helix pomatia agglutinin, and soybean agglutinin) and three monoclonal antibodies (HBTn-1, B1.1, and Bric111) that bind the tumor-associated Tn antigen. In addition, serum antibodies were profiled from 30 healthy donors. The results show that variations in antigen density are required to detect the full spectrum of antibodies that bind a particular antigen and can be used to reveal differences in antibody populations between individuals that are not detectable using a single antigen density.
Collapse
Affiliation(s)
- Oyindasola Oyelaran
- Laboratory of Medicinal Chemistry, National Cancer Institute, 376 Boyles Street, Building 376, Frederick, Maryland 21702, USA
| | | | | | | |
Collapse
|
10
|
Singha B, Adhya M, Chatterjee BP. Catfish (Clarias batrachus) serum lectin recognizes polyvalent Tn [α-d-GalpNAc1-Ser/Thr], Tα [β-d-Galp-(1→3)-α-d-GalpNAc1-Ser/Thr], and II [β-d-Galp(1→4)-β-d-GlcpNAc1-] mammalian glycotopes. Carbohydr Res 2008; 343:2384-92. [DOI: 10.1016/j.carres.2008.06.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 06/26/2008] [Accepted: 06/28/2008] [Indexed: 11/17/2022]
|
11
|
Singh T, Wu J, Peumans W, Rougé P, Van Damme E, Alvarez R, Blixt O, Wu A. Carbohydrate specificity of an insecticidal lectin isolated from the leaves of Glechoma hederacea (ground ivy) towards mammalian glycoconjugates. Biochem J 2006; 393:331-41. [PMID: 16156719 PMCID: PMC1383692 DOI: 10.1042/bj20051162] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Preliminary studies indicated that the potent insecticidal lectin, Gleheda, from the leaves of Glechoma hederacea (ground ivy) preferentially agglutinates human erythrocytes carrying the Tn (GalNAcalpha1-Ser/Thr) antigen. However, no details have been reported yet with respect to the fine specificity of the lectin. To corroborate the molecular basis of the insecticidal activity and physiological function of Gleheda, it is necessary to identify the recognition factors that are involved in the Gleheda-glycotope interaction. In the present study, the requirement of high-density multivalent carbohydrate structural units for Gleheda binding and a fine-affinity profile were evaluated using ELLSA (enzyme-linked lectinosorbent assay) with our extended glycan/ligand collections, a glycan array and molecular modelling. From the results, we concluded that a high-density of exposed multivalent Tn-containing glycoproteins (natural armadillo and asialo ovine salivary glycoproteins) were the most potent factors for Gleheda binding. They were, on a nanogram basis, 6.5x10(5), 1.5x10(4) and 3.1x10(3) times more active than univalent Gal (galactose), GalNAc (N-acetylgalactosamine) and Tn respectively. Among mono- and oligo-saccharides examined, simple clustered Tn (molecular mass <3000 Da) from ovine salivary glycoprotein was the best, being 37.5 and 1.7x10(3) times better than GalNAc and Gal respectively. GalNAc glycosides were significantly more active than Gal glycosides, indicating that the N-acetamido group at C-2 plays an important role in Gleheda binding. The results of glycan array support the conclusions drawn with respect to the specificity of Gleheda based on the ELLSA assays. These findings combined with the results of the molecular modelling and docking indicate the occurrence of a primary GalNAcalpha1-binding site in the Gleheda monomer. However, the extraordinary binding feature of Gleheda for glycoproteins demonstrates the importance of affinity enhancement by high-density multivalent glycotopes in the ligand-lectin interactions in biological processes.
Collapse
Affiliation(s)
- Tanuja Singh
- *Glyco-immunochemistry Research Laboratory, Institute of Molecular and Cellular Biology, College of Medicine, Chang-Gung University, Kwei-San, Tao-Yuan, 333, Taiwan
| | - June H. Wu
- †Department of Microbiology and Immunology, College of Medicine, Chang-Gung University, Kwei-San, Tao-Yuan, 333, Taiwan
| | - Willy J. Peumans
- ‡Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - Pierre Rougé
- §Surfaces Cellulaires et Signalisation chez les Végétaux, UMR-CNRS 5546, Pôle de Biotechnologie végétale, Chemin de Borde-Rouge, 31326 Castanet Tolosan, France
| | - Els J. M. Van Damme
- ‡Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - Richard A. Alvarez
- ∥Department of Biochemistry and Molecular Biology, University of Oklahoma, Health Sciences Center, Oklahoma City, OK 73104, U.S.A
| | - Ola Blixt
- ¶Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, U.S.A
| | - Albert M. Wu
- *Glyco-immunochemistry Research Laboratory, Institute of Molecular and Cellular Biology, College of Medicine, Chang-Gung University, Kwei-San, Tao-Yuan, 333, Taiwan
- To whom correspondence should be addressed (email )
| |
Collapse
|
12
|
Vega N, Pérez G. Isolation and characterisation of a Salvia bogotensis seed lectin specific for the Tn antigen. PHYTOCHEMISTRY 2006; 67:347-55. [PMID: 16413042 DOI: 10.1016/j.phytochem.2005.11.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 09/30/2005] [Accepted: 11/23/2005] [Indexed: 05/06/2023]
Abstract
A lectin was isolated and characterised from Salvia bogotensis seeds. Removal of the abundant pigments and polysaccharides, which are present in seeds, was an essential step in its purification. Several procedures were assayed and the best suited, including Pectinex treatment, DEAE-cellulose and affinity chromatography, led to a protein being obtained amounting to 18-20mg/100g seeds having high specific agglutination activity (SAA). The lectin specifically agglutinated human Tn erythrocytes and was inhibited by 37mM GalNAc, 0.019mM ovine submaxillary mucin (OSM) or 0.008mM asialo bovine submaxillary mucin (aBSM). Enzyme-linked lectinosorbent assay (ELLSA) revealed strong binding to aOSM and aBSM, corroborating Tn specificity, whereas no binding to fetuin or asialo fetuin was observed. The lectin's monomer MW (38,702Da), amino acid composition, pI, carbohydrate content, deglycosylated form MW, thermal stability and Ca(2+) and Mn(2+) requirements were determined. Evidence of the existence of two glycoforms was obtained. The lectin's specificity and high affinity for the Tn antigen, commonly found in tumour cells, makes this protein a useful tool for immunohistochemical and cellular studies.
Collapse
Affiliation(s)
- Nohora Vega
- Biochemistry Laboratory, Chemistry Department, Universidad Nacional de Colombia, Bogotá, Colombia
| | | |
Collapse
|
13
|
Wu AM. Lectinochemical studies on the glyco-recognition factors of a Tn (GalNAcα1→Ser/Thr) specific lectin isolated from the seeds of Salvia sclarea. J Biomed Sci 2005; 12:167-84. [PMID: 15864748 DOI: 10.1007/s11373-004-8180-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The lectin extracted from the seeds of Salvia sclarea (SSL) recognizes the Tn antigen (GalNAc alpha1-->Ser/Thr) expressed in certain human carcinomas. In previous studies, knowledge of the binding properties of SSL was restricted to GalNAcalpha1--> related oligosaccharides and glycopeptides. Thus, the requirements of functional groups in monosaccharide and high-density polyvalent carbohydrate structural units for SSL binding and an updated affinity profile were further evaluated by enzyme-linked lectinosorbent (ELLSA) and inhibition assays. Among the glycoproteins (gps) tested for interaction, a high density of exposed Tn-containing glycoproteins such as in the armadillo salivary Tn glycoprotein and asialo ovine salivary glycoprotein reacted best with SSL. When the gps were tested for inhibition of SSL binding, which was expressed as 50% nanogram inhibition, the high density polyvalent Tn present in macromolecules was the most potent inhibitor. Among the monosaccharide and carbohydrate structural units studied, which were expressed as nanomole inhibition, GalNAc alpha1-->3GalNAc beta1-->3Gal alpha1-->4Gal beta1-->4Glc (Fp), GalNAc alpha1-->3Gal beta1-->4Glc (A(L)), GalNAc alpha1-->3GalNAc beta1-->Me (F beta), GalNAc alpha1-->3GalNAc alpha1-->Me (F alpha) and GalNAc alpha1--> Ser/Thr (Tn) were the most active ligands, being 2.5-5.0 x 10(3) and 1.25-2.5 times more active than Gal and GalNAc, respectively. From the results, it is suggested that the combining site of SSL is a shallow groove type, recognizing the monosaccharide of GalNAc as the major binding site or Tn up to the Forssman pentasaccharide (Fp). It can be concluded that the three critical factors for SSL binding are the -NH CH(3)CO at carbon-2 in Gal, the configuration of carbon-3 in GalNAc, and the polyvalent Tn (GalNAc alpha1-->Ser/Thr) present in macromolecules. These results should assist in understanding the glyco-recognition factors involved in carbohydrate-lectin interactions in biological processes. The effect of the polyvalent F alpha, F beta and GalNAc beta1-->3Gal alpha1--> (P alpha) glycotopes on binding should be examined. However, this is hampered by the lack of availability of suitable reagents.
Collapse
Affiliation(s)
- Albert M Wu
- Glyco-Immunochemistry Research Laboratory, Institute of Molecular and Cellular Biology, College of Medicine, Chang-Gung University, Kweishan, Taoyuan 333, Taiwan.
| |
Collapse
|
14
|
Medeiros A, Berois N, Balter H, Robles A, Perez-Payá E, Gimenez A, Calvete JJ, Osinaga E. Monoclonal antibodies against the Tn-specific isolectin B4 from Vicia villosa seeds: characterization of the epitope of the blocking antibody VV34. HYBRIDOMA AND HYBRIDOMICS 2004; 23:39-44. [PMID: 15000847 DOI: 10.1089/153685904322772015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Vicia villosa isolectin B4 (VVLB4) recognizes the Tn antigen (GalNAc-O-Ser/Thr) exposed in certain human carcinomas. We have produced anti-VVLB4 monoclonal antibodies (MAbs), and their lectin recognition selectivity was assessed by ELISA and Western blot against the purified Gal/GalNAc-specific lectins from Vicia villosa, Salvia sclarea, Helix pomatia, Arachis hypogaea, Glycine max, and Dolichos biflorus. The antibodies were also tested for their ability to block the binding of VVLB4 to the Tn antigen expressed on immobilized asialo ovine submaxillary mucin. Two MAbs, VV34 and VV2, specifically recognized VVLB4 and impaired the binding of the lectin to the Tn antigen by 98% and 21%, respectively. On the other hand, MAbs VV1 and VV22 cross-reacted with other purified lectins. The four antibodies recognized native and periodate-oxidized nonreduced as well as reduced VVLB4 after SDS-PAGE and Western blot, suggesting that they were recognizing continuous polypeptide epitopes. The VV34 antibody recognized two tryptic peptides (7-29 and 96-106) from VVLB4, which are contiguous in the three-dimensional structure of the lectin. The minimum structural determinant of the epitope was mapped to the polypeptide stretch (18)LILQED(23) using a set of overlapping synthetic peptides. This region of the molecule encompasses the C-terminal part of the loop joining strands beta1 and beta2 and the N-terminal part of beta2, and is located about 20-25 A away from the center of the Tn-combining site.
Collapse
Affiliation(s)
- Andrea Medeiros
- Dept. de Bioquímica, Facultad de Medicina, Universidad de la Republica, Montevideo, Uruguay
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Wu AM. Polyvalency of Tn (GalNAcα1→Ser/Thr) glycotope as a critical factor forVicia villosaB4and glycoprotein interactions. FEBS Lett 2004; 562:51-8. [PMID: 15044001 DOI: 10.1016/s0014-5793(04)00180-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Revised: 01/28/2004] [Accepted: 01/29/2004] [Indexed: 11/28/2022]
Abstract
Vicia villosa B(4) (VVL-B(4)) is an important lectin for detecting exposed Tn (GalNAcalpha1-Ser/Thr) determinants on cancer cells. In order to elucidate the binding factors involved in VVL-B(4) and glycotope interaction, the binding properties of this lectin were analyzed by enzyme-linked lectinosorbent and inhibition assays. From the results, it is concluded that the most critical factor affecting VVL-B(4) binding is polyvalency at the alpha anomer of Gal with -NH CH(3)CO at carbon-2 (Tn epitope), which enhances the reactivity by 3.3x10(5) times over monovalent Gal. The reactivities of glycotopes can be ranked as follows: high density Tn cluster >>Tn glycopeptides (MW<3.0x10(3) >> monomeric Tn to tri- Tn glycopeptides >>> other GalNAcalpha/beta-related structural units>Gal and Galalpha- or beta-linked ligands, demonstrating the essential role of the polyvalency of Tn glycotopes in the enhancement of the binding.
Collapse
Affiliation(s)
- Albert M Wu
- Glyco-Immunochemistry Research Laboratory, Institute of Molecular and Cellular Biology, College of Medicine, Chang-Gung University, Kwei-San, Tao-Yuan 333, Taiwan.
| |
Collapse
|
16
|
Zheng M, Ruan Y, Yang M, Guan Y, Wu Z. The comparative study on ultrastructure and immunohistochemistry in AFP negative and positive hepatocellular carcinoma. Curr Med Sci 2004; 24:547-9, 559. [PMID: 15791836 DOI: 10.1007/bf02911350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Indexed: 12/12/2022]
Abstract
SUMMARY To comparatively investigate ultrastructural characteristics and expressions of AFP (alpha-fetoprotein) and Tn (Thomsen-Friedenreich-related antigen) protein in AFP negative (AFP-) and AFP positive (AFP+) primary hepatocellular carcinoma. Fourty-three cases of AFP- and AFP+ hepatocellular carcinoma (HCC) tissues and five cases of normal liver tissues were divided into three groups: control group (normal liver tissue, n=5); AFP+ HCC group (the serum AFP level was higher than 10 ng/ml, n = 22); AFP- HCC group (the serum AFP level was lower than 10 ng/ml, n=21). The ultrastructural morphology was studied by transmission electron microscopy, the expressions of AFP and Tn protein were detected by immunohistochemistry and cell image analysis. 1. The immunohistochemical study showed that (1) the expression intensity and positive rate of Tn protein in AFP- HCC group were markedly higher than that in AFP+ HCC group (P<0.01); (2) The expression intensity of AFP in AFP- HCC group was lower than that in AFP+ HCC group (P<0.01). 2. The transmission electron microscopy demonstrated that some AFP- HCC cells linked closely with each other, others dispersed loosely just as cultured cells, the remarkable morphologic features in AFP- HCC cells were simple organelles, but they were abundant in the free polyribosomes. In AFP+ HCC group, all the HCC cells linked closely together and were rich organelles in their cytoplasm, especially the rough endoplasmic reticula. In addition, mitochondria and Golgi complex were obviously observed. (1) The AFP and Tn protein had discrepancy distribution in AFP- and AFP+ HCC tissues, Tn protein may be one of the early diagnostic indicators in AFP- HCC; (2) The synthetic locations of the AFP and Tn protein were different in hepatocarcinoma cells by ultrastructural observation.
Collapse
Affiliation(s)
- Meirong Zheng
- Department of Ultrastructural Pathology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | | | | | | | | |
Collapse
|
17
|
Wang W, Hause B, Peumans WJ, Smagghe G, Mackie A, Fraser R, van Damme EJM. The Tn antigen-specific lectin from ground ivy is an insecticidal protein with an unusual physiology. PLANT PHYSIOLOGY 2003; 132:1322-34. [PMID: 12857814 PMCID: PMC167072 DOI: 10.1104/pp.103.023853] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2003] [Revised: 03/26/2003] [Accepted: 03/30/2003] [Indexed: 05/21/2023]
Abstract
Leaves of ground ivy (Glechoma hederacea) contain a lectin (called Gleheda) that is structurally and evolutionary related to the classical legume lectins. Screening of a population of wild plants revealed that Gleheda accounts for more than one-third of the total leaf protein in some clones, whereas it cannot be detected in other clones growing in the same environment. Gleheda is predominantly expressed in the leaves where it accumulates during early leaf maturation. The lectin is not uniformly distributed over the leaves but exhibits a unique localization pattern characterized by an almost exclusive confinement to a single layer of palisade parenchyma cells. Insect feeding trials demonstrated that Gleheda is a potent insecticidal protein for larvae of the Colorado potato beetle (Leptinotarsa decemlineata). Because Gleheda is not cytotoxic, it is suggested that the insecticidal activity is linked to the carbohydrate-binding specificity of the lectin, which as could be demonstrated by agglutination assays with different types of polyagglutinable human erythrocytes is specifically directed against the Tn antigen structure (N-acetylgalactosamine O-linked to serine or threonine residues of proteins).
Collapse
Affiliation(s)
- Weifang Wang
- Department of Molecular Biotechnology, Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | | | | | | | | | | | | |
Collapse
|
18
|
Fernández-Alonso JL, Vega N, Filgueira JJ, Pérez G. Lectin prospecting in Colombian Labiatae. A systematic-ecological approach. BIOCHEM SYST ECOL 2003. [DOI: 10.1016/s0305-1978(02)00223-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
19
|
Babino A, Tello D, Rojas A, Bay S, Osinaga E, Alzari PM. The crystal structure of a plant lectin in complex with the Tn antigen. FEBS Lett 2003; 536:106-10. [PMID: 12586347 DOI: 10.1016/s0014-5793(03)00037-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The structure of the tetrameric Vicia villosa isolectin B4 (VVLB4) in complex with a cancer antigen, the Tn glycopeptide (GalNAc-O-Ser), was determined at 2.7 A resolution. The N-acetylgalactoside moiety of the ligand binds to the primary combining site of VVLB4 in a similar way as observed for other Gal/GalNAc-specific plant lectins. The amino acid moiety of the Tn antigen is largely exposed to the solvent and makes few contacts with the protein. The structure of the complex provides a framework to understand the differences in the strength of VVLB4 binding to different sugars and emphasizes the role of a single protein residue, Tyr127, as a structural determinant of Tn-binding specificity.
Collapse
Affiliation(s)
- Alvaro Babino
- Departamento de Bioquimica, Facultad de Medicina, Av. Gral Flores 2125, Montevideo, Uruguay
| | | | | | | | | | | |
Collapse
|
20
|
Wang W, Peumans WJ, Rougé P, Rossi C, Proost P, Chen J, Van Damme EJM. Leaves of the Lamiaceae species Glechoma hederacea (ground ivy) contain a lectin that is structurally and evolutionary related to the legume lectins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2003; 33:293-304. [PMID: 12535343 DOI: 10.1046/j.1365-313x.2003.01623.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A novel lectin has been isolated and cloned from leaves of Glechoma hederacea (ground ivy), a typical representative of the plant family Lamiaceae. Biochemical analyses indicated that the G. hederacea agglutinin (Gleheda) is a tetrameric protein consisting of four subunits pairwise linked through an interchain disulphide bridge and exhibits a preferential specificity towards N-acetylgalactosamine. Cloning of the corresponding gene and molecular modeling of the deduced sequence demonstrated that Gleheda shares high sequence similarity with the legume lectins and exhibits the same overall fold and three-dimensional structure as the classical legume lectins. The identification of a soluble and active legume lectin ortholog in G. hederacea not only indicates that the yet unclassified Lamiaceae lectins belong to the same lectin family as the legume lectins, but also sheds a new light on the specificity, physiological role and evolution of the classical legume lectins.
Collapse
Affiliation(s)
- Weifang Wang
- Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
| | | | | | | | | | | | | |
Collapse
|
21
|
Robles AM, Balter HS, Oliver P, Welling MM, Pauwels EK. Improved radioiodination of biomolecules using exhaustive Chloramine-T oxidation. Nucl Med Biol 2001; 28:999-1008. [PMID: 11711320 DOI: 10.1016/s0969-8051(01)00261-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
To improve standardization in analytical reagents we investigated Chloramine-T radioiodination (125I) of several biomolecules based on the use of a single amount of the oxidizing agent Chloramine-T as the limiting reagent being exhausted during the course of the reaction. Whenever the labeling yield resulted in less than one atom 125I/molecule, a second amount of the oxidizing agent was added. Thereafter, the integrity of the various biomolecules was assessed using radioimmunoassays, radioreceptor binding assays, or radioimmunometric assays. Purification yields were done by gel permeation (56% +/- 19%, n=230) or by precipitation with trichloroacetic acid (59% +/- 19%, n=230). Specific activity (117 +/- 61 MBq/nmol) and the degree of iodine incorporation (1.4 +/- 0.8 atoms of 125I/molecule) were achieved after 300 sec of incubation. A second addition of Chloramine-T resulted in an increased labeling yield of all biomolecules tested by a mean factor of 1.8 +/- 0.9. After the second addition of Chloramine-T, we observed for some biomolecules a significant (p<0.001) decreased effect in biological performance. In conclusion, the use of Chloramine-T as a limiting reagent resulted in molecules with appropriate immunological and biological performance. In general, tracers were minimally damaged and assessment of the shelf life as well as storing conditions showed the usefulness of the standardization of biomolecule labeling.
Collapse
Affiliation(s)
- A M Robles
- Radiopharmacy Department, Nuclear Research Center, Faculty of Sciences, Montevideo, Uruguay.
| | | | | | | | | |
Collapse
|
22
|
Alvarez Errico D, Medeiros A, Míguez M, Casaravilla C, Malgor R, Carmona C, Nieto A, Osinaga E. O-glycosylation in Echinococcus granulosus: identification and characterization of the carcinoma-associated Tn antigen. Exp Parasitol 2001; 98:100-9. [PMID: 11465993 DOI: 10.1006/expr.2001.4620] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present work we demonstrate that the cancer-associated O-glycosylated Tn antigen (GalNAc-O-Ser/Thr) is expressed by the cestode Echinococcus granulosus. This antigen was detected in both larval and adult worm extracts, with the highest specific activity observed in the adult excretion/secretion preparation. Histochemical analysis showed that Tn is preferentially expressed in the parenchyma in both parasite stages and the external part of tegument in adult worms. A similar pattern was observed for sialyl-Tn, a related O-linked antigen. Tn glycoproteins from protoscoleces were resolved by SDS-PAGE in two main components of 43 and 49 kDa. After purification, this material was reactive with lectins which bind GlcNAc/sialic acid, GalNAc, and T antigen. In a preliminary evaluation, high levels of Tn antigen were detected in serum samples from patients with hydatid cyst, suggesting that the measure of Tn in serum could be a biomarker of this disease, although extensive work is necessary in order to determine the clinical usefulness of this assay. The results reported here, the first evidence of O-glycosylation pathways in E. granulosus and the presence of Tn antigen in cestodes, suggest that the evaluation of O-glycosylated antigens might give new insights in the host-parasite relationship.
Collapse
|