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S Gabius

Publications and source records attributed to S Gabius.

At least 19 recordsLinked to original sources
PubMed1992

Analysis of tumour necrosis factor alpha-specific, lactose-specific and mistletoe lectin-specific binding sites in human lung carcinomas by labelled ligands.

Receptor sites can be visualized by labelled ligands as an alternative to receptor-specific antibodies, as substantiated for two different receptor classes. Recombinant tumour necrosis factor alpha (TNF) was biotinylated via amino-groups and the resultant probe was applied to formalin-fixed, paraffin-embedded tissue sections of 94 primary bronchial carcinomas and to normal peripheral lung parenchyma. In addition, monoclonal antibodies specific for neuron-specific enolase (NSE) and TNF itself were used. The biotinylated beta-galactoside-specific mistletoe lectin, which exhibits dose-dependent immunomodulatory and toxic potency, and two probes that specifically detect certain types of sugar receptors were employed to illustrate further the feasibility of using ligands for receptor localisation. The tumours comprised 62 small cell lung carcinomas, 10 epidermoid carcinomas, 11 adenocarcinomas and 11 large cell anaplastic carcinomas. Expression of TNF-binding sites was found in 39 of the small cell lung carcinomas and in 13 of the non-small cell lung carcinomas. Binding capacity for the TNF-specific antibody was seen in similar proportions of small cell lung carcinomas and of non-small cell lung carcinomas. None of the normal lung parenchymas revealed significant staining. Binding capacities to mistletoe lectin were seen in all normal lung parenchymas and in nearly all cases of adenocarcinoma (10/11). A correlation between the expression of NSE and the binding capacities to TNF was detected. Endogenous lectins, specific for lactose or beta-GalNAc, were displayed in nearly one half of the small cell lung carcinoma cases (44% or 45% respectively) and in about 25% of the non-small cell lung carcinoma cases.

Acetylgalactosamine↗
PubMed1992

Studies on carbohydrate-binding proteins using liposome-based systems--I. Preparation of neoglycoprotein-conjugated liposomes and the feasibility of their use as drug-targeting devices.

1. Five types of neoglycoprotein-coupled liposomes were prepared in order to investigate their potential utility as new types of drug-targeting devices which exploit cellular functions of carbohydrate-binding proteins. 2. These preparations were shown to be stable at 37 degrees C for 24 hr and at 7 degrees C over 4 months. 3. An inhibition assay in an in vitro system using human adenocarcinoma cells indicated the high affinity binding of neoglycoprotein-conjugated liposomes. The inhibitory potency correlated with both the type and the amount of immobilized neoglycoproteins on liposomes. 4. A tissue distribution assay in an in vivo system using Ehrlich solid tumor-bearing mice showed the feasibility of the application of [125I]neoglycoprotein-conjugated liposomes as drug-targeting devices, based on carbohydrate-protein interactions.

Carbohydrate Metabolism↗
PubMed1991

Glycopeptide-albumin derivative: it preparation and histochemical ligand properties.

Carrier-immobilized mono- or disaccharides and other carbohydrate structures, derived by custom-made chemical synthesis, have already proven to be valuable ligands for localizing carbohydrate-binding proteins in tissue sections. Defined purified glycopeptides, as components of neoglycoproteins, offer the possibility of increasing their structural complexity and, thereby, their receptor selectivity. To test the feasibility of this approach, the glycopeptide man6-glcNAc2-asparagine derived from ovalbumin was purified after pronase digestion. It was coupled to bovine serum albumin as carrier protein with the homobifunctional linking agent bis-(sulphosuccinimidyl)suberate to yield the diglycosylated concanavalin A-reactive product. Following biotinylation, it was used to detect mannose-specific binding sites in fixed cells of seven human leukemia or lymphoma lines and in fixed, paraffin-embedded sections of human breast cancer. In comparison to chemically mannosylated bovine serum albumin with ten sites of glycosylation or to ovalbumin, this derivative produced a similar pattern of reaction with a quantitatively lower extent of staining in most cases. Remarkably, the presence of potential endogenous ligands for the detected receptor sites was ascertained using the plant lectin concanavalin A. Thus, the conjugation of a purified, deliberately selected glycopeptide to a suitable carrier produces a histochemical tool for detecting glycopeptide-specific binding sites.

Asparagine↗
PubMed1991

Neoglycoprotein binding to colorectal tumour cells: comparison between primary and secondary lesions.

Biotinylated neoglycoproteins are useful to determine the expression of sugar receptors (lectins) histochemically in routinely processed tissue sections. Assessment of the presence of distinct receptor classes with specificity to beta-galactosides and to alpha- or beta-N-acetylgalactosamine, selected on the basis of their potential relevance for recognition processes within the metastatic cascade in murine model systems, was performed for a common human tumour type, colorectal cancer. The four different types of neoglycoproteins, derived from covalent attachment of commercially available derivatives of beta-N-acetylgalactosamine, differed only quantitatively in their capacity to detect specific binding on cultured cells and tissue sections, thus posing no major restriction on the choice of synthetic process for histochemical efficiency of the product. Glycocytological application revealed specific probe binding and a regulation of level of receptor expression for a human colon carcinoma cell line primarily for N-acetylgalactosamine-specific receptors upon retinoic acid-induced differentiation. Monitoring of sections of the 12 cases of primary and secondary colorectal lesions invariably disclosed the presence of the respective receptors, the extent of cell labelling in primary tumours and metastases being similar. Establishment of metastases, even in different target organs, is apparently not followed by a major phenotypic variation in this feature.

Acetylgalactosamine↗
PubMed1991

[Biotinylated ligands for receptor localization. An alternative for immunohistochemistry].

Immunohistochemical techniques are prerequisite for the classification and characterization of numerous diseases. The incubation with labelled ligands is an alternative to immunohistochemistry, and allows the recognition of receptors independent from their immunogenic properties. The biotinylation and immobilization of small molecules such as sugars can be performed under the conservation of active receptor-binding sites. Certain sugars bound to bovine serum albumin are highly specific markers for bronchial carcinomas and lung parenchyma altered by cytostatic drug regimes, infection or inflammation. Biotinylated growth factors such as epidermal growth factor or biotinylated hormones are useful tools for the demonstration of the corresponding receptors. These tools are called "neoligandoproteins". The number specific binding sites and the thermodynamic binding parameters can be measured with sugars bound to enzymes. The number of and the expression of specific sugar binding sites can be correlated to the differentiation and metastatic potency of malignant tumors. In addition, cytostatic drugs can be bound to carbohydrates. This technique offers new perspectives in the affinity and quantification of target-related cytostatic drug regimens.

Animals↗
PubMed1990

Analysis of cell-surface sugar receptor expression by neoglycoenzyme binding and adhesion to plastic-immobilized neoglycoproteins for related weakly and strongly metastatic cell lines of murine tumor model systems.

Recognition of the carbohydrate part of cellular glycoconjugates by cell-surface sugar receptors may contribute to interactions, essential to the establishment of metastases. Comparison of the properties of strongly metastatic variants to their related, less metastatic counterparts offers a generally accepted approach to the discovery of metastasis-associated characteristics. The chemically induced murine lymphoma line Eb and its spontaneously arising variant ESb with increased potential for lung and liver colonization, the virally induced lymphosarcoma cell line RAW117-P and its in vivo selected variant H10 with increased potential for liver colonization, and the B16-F1 melanoma line and its in vivo selected variant F10 with increased potential for lung colonization, were chosen. A panel of 12 types of chemically glycosylated E. coli beta-galactosidase, exposing the pivotal carbohydrate residues for specific carbohydrate-dependent cell binding, was employed to study the expression of respective cell-surface sugar receptors on these cell lines. Specific binding occurred in a non-uniform manner for the individual probes. Systematic measurements at a non-saturating ligand concentration revealed quantitative differences between the 2 cell lines of each system. However, there were no consistent changes associated with the metastatic phenotype. A similar result was obtained employing Scatchard analyses for quantitative evaluation of binding characteristics in several cases. Surface receptor expression was responsive to chemical induction of differentiation in the lymphosarcoma model. Analyses of sugar-inhibitable cell adhesion to neoglycoprotein-coated plastic wells for the lymphoma and lymphosarcoma cells revealed that the presence of cell-surface sugar receptors, even at similar densities to those defined by neoglycoenzyme binding, will not necessarily translate into an identical adhesive response. Several carbohydrates, especially N-acetyl-D-galactosamine, can differentially affect this interaction at a non-toxic concentration in both model systems.

Acetylgalactosamine↗
PubMed1990

Carrier-immobilized derivatized lysoganglioside GM1 is a ligand for specific binding sites in various human tumor cell types and peripheral blood lymphocytes and monocytes.

Biotinylation of ganglioside-protein conjugates, derived from selective N-acylation of the sphingoid amino group of deacylated ganglioside GM1 or a ganglioside mixture, yielded probes to detect specific binding sites in fixed specimens. GM1-containing neoligandoprotein significantly bound to tumor cells in sections of 15 out of 16 cases of human lung cancer, while the probe, derived from the mixture, was ineffective under these conditions. The same graduation of staining was under identical conditions observed with these two probes on fixed human tumor cells and on peripheral blood lymphocytes and monocytes. Attempts of biochemical isolation of proteins, responsible for this binding capacity, from tumor cell extracts in the presence of the abundant endogenous ligands led to protein bands with apparent molecular weights of 44,000, 68,000 and 72,000 with yields of 0.1-0.24 micrograms/mg protein, after the detergent extracts had been passed over a resin, exposing gangliosides of the markedly less efficient mixture, to exclude binding by non-specific ionic or hydrophobic interactions.

Binding Sites↗
PubMed1990

[Tumor lectinology--status and perspectives of clinical application].

A detailed knowledge of the mechanisms of molecular recognition is a prerequisite to rationally improved diagnostic and therapeutic procedures in diseases. In addition to sequences of amino acids, carbohydrate structures apparently store biological information that is thought to be relevant for physiologically important processes. Such ligands, namely the carbohydrate part of cellular glycoconjugates, can be recognized by specific endogenous binding proteins like lectins. If their presence can be reliably ascertained and correlated to the clinical course of the disease, e.g. in oncology, lectinology may help to define a yet undisclosed role for this class of proteins in tumor progression and spread.

Animals↗
PubMed1990

Sugar receptors of the stromal cell layer in human long-term bone marrow cultures: their presence, modulatory responses to changes in the microenvironment and potential role in cellular adhesion.

Intimate cellular contacts and coordinated supply of regulatory factors are required to maintain the still inexplicable dynamic equilibrium of hemopoiesis. To infer the potential participation of protein-carbohydrate interaction in this complex process, human long-term bone marrow cultures were initiated from eleven donors, and the adherent cell layer was characterized enzyme- and immunohistochemically. Utilizing an array of carrier-immobilized carbohydrate ligands and sulfated polysaccharides as probes, specific binding of various constituents of the carbohydrate chains of cellular glycoconjugates to the stromal cells was unmistakably disclosed. Biochemical analysis, employing glycocytologically effective ligands in affinity chromatography, corroborated this result. The extent of binding was markedly lower in the two samples, derived from leukemia patients. Pronounced adaptive responses for this characteristic followed changes in the culture microenvironment that are known to influence qualitative and quantitative aspects of hemopoiesis in vitro, namely omission of hydrocortisone and horse serum or addition of cytokines. Similarly, such adaptive modulation occurred on the level of accessible cell surface receptors, monitored by neoglycoenzymes. These binding sites can be involved in mediation of cellular interactions, as revealed in a model system by the interference of N-acetyl-D-galactosamine in cell adhesion. Overall, the results support the idea that glycobiological recognition may contribute to the functional integrity of the stromal cell layer as well as provide the basis for further analysis.

Bone Marrow↗
PubMed1990

Binding of T-antigen-bearing neoglycoprotein and peanut agglutinin to cultured tumor cells and breast carcinomas.

Chemical conjugation of appropriate carbohydrate ligands to an inert labeled carrier renders probes available to screen for the presence of respective binding sites. A set with a certain plant lectin and a suitable neoglycoprotein can thus determine complementary parts of a potentially relevant glycobiological interaction system. Owing to the interest in the peanut agglutinin-reactive T-antigen, we performed chemical synthesis of the respective disaccharide structure to serve as glycohistochemical ligand and established refinements of the synthetic patway. Coupling of the derivatized monomers had to be performed in the presence of sodium sulfate for optimal results. Complete removal of the protective groups from the p-nitrophenyl derivative of the N-acetylgalactosamine moiety was achieved under mild conditions with 2,3-dichloro-5,6-dicyanobenzoquinone without affecting any other functional groups. Specific binding sites for the synthetic neoglycoprotein as well as for the plant lectin were demonstrated in cell lines of human breast carcinoma colon adenocarcinoma, and erythroleukemia. ABC reagents in conjunction with DAB as peroxidase substrate were used to visualize specific binding sites. Binding complied with the accepted criteria for specificity. Moreover, carbohydrate-specific binding sites were detected in sections of nine out of 14 cases with malignant breast lesions. The percentage of positive tumor cells with both neoglycoprotein and lectin was similar in each of the individual sections, regardless of quantitative variations between cases, lectin staining intensity often being more pronounced. The reactivity pattern in sections of primary and metastatic lesions was not significantly correlated with the lymph node status. This study emphasized that custom synthesis of saccharides and histochemical application of the resulting neoglycoprotein has a remarkable potential for complementary assessment of endogenous binding sites for carbohydrate structures, localized by external tools such as plant lectins, as a step to elucidate the importance of a putative proteincarbohydrate interaction.

Adenocarcinoma↗
PubMed1990

Endogenous lectins with specificity to beta-galactosides and alpha- or beta-N-acetyl-galactosaminides in human breast cancer. Their glycohistochemical detection in tissue sections by synthetically different types of neoglycoproteins, their quantitation on cultured cells by neoglycoenzymes and their usefulness as targets in lectin-mediated phototherapy in vitro.

Endogenous lectins may augment the panel of tumor markers. Specific protein-carbohydrate interactions especially involve carbohydrate moieties that are located at sequence termini, e.g. D-galactose and N-acetyl-D-galactosamine. Respective endogenous lectins can be detected by suitably constructed neoglycoproteins. In order to evaluate the influence of sugar and label density as well as coupling mode of the carbohydrate moiety to the carrier protein for lectin localization in histopathology, four different types of neoglycoproteins, carrying beta-galactosides or alpha- and beta-anomers of N-acetyl-D-galactosamine were employed to reveal the presence of specific receptors in invasive ductal mammary carcinomas with propensity for metastasis formation. Staining of tumor cells was more intense than staining of normal cell types. Coupling of the diazo derivatives of p-aminophenyl glycosides led in most cases to the relatively highest extent of staining in terms of number of stained cells and staining intensity. Classified next according to these categories attachment of sugars via p-isothiocyanato derivatives or via an aliphatic linker after his reaction with the C6-hydroxyl group of the sugar moiety was rather equally well effective, whereas reductive amination with concomitant ring opening at the reducing end of the disaccharide lactose resulted in neoglycoproteins, yielding the lowest extent of staining. The alpha-anomer is preferred as a ligand to endogenous lectins of tumor cells to the beta-anomer of N-acetyl-D-galactosamine. To reduce the number of steps in glycohistochemical processing, glycosylated enzymes were successfully employed. They also allowed to measure the lectin density on breast carcinoma cells, leading to rational selection for demonstrated lectin-mediated targeting of neoglycoprotein-hematoporphyrin conjugates. Immobilization of ligands as an approach to prepare histochemically valuable reagents to localize respective receptors is not confined to tumor lectinology, as emphasized by additional application of hormone-protein conjugates, termed neohormoproteins.

Acetylgalactosamine↗
PubMed1989

Neoglycoenzymes: a versatile tool for lectin detection in solid-phase assays and glycohistochemistry.

Carbodiimide-mediated coupling of p-aminophenyl glycosides to a naturally nonglycosylated enzyme yields a neoglycoenzyme. This compound combines inherent enzymatic activity with synthetically conferred ligand properties to lectins. Appropriate choice of the ligand allows custom-made synthesis to reliably detect various types of lectins. To exemplify practical applications of this class of compounds, glycosylated bacterial beta-galactosidase has been employed to quantitate plant lectins, immobilized on plastic surfaces as well as on nitrocellulose. Competitive inhibition by specific sugar ascertained the dependence of binding on protein--carbohydrate interactions. In view of lectins as tools, a sandwich lectin-binding assay for high mannose-type glycoprotein detection has been modified to principally facilitate wide application to other lectin-reactive sugar chains by introducing the neoglycoenzyme. In addition to lectin determination in solid-phase assays, neoglycoenzymes allow one to glycohistochemically localize endogenous lectins in tissue prints and tissue sections with a minimum number of steps. This nonradioactive, rapid, sensitive, and convenient assay concept, based on conjugation of a ligand to an enzyme with maintenance of its receptor-binding activity, may find extended application beyond lectinology in receptor analysis.

Biotin↗
PubMed1989

Identification of a cell cycle-dependent gene product as a sialic acid-binding protein.

A Ca2+-dependent sialic acid-binding protein was purified on fetuin-Sepharose from various types of human tissue. The molecular mass was determined to be 10,315 Da by laser desorption mass spectrometry. Partial sequence analysis after cyanogen bromide cleavage that yielded one N-terminus accessible for Edman degradation revealed an identity to an internal stretch following the only methionine residue within a putative amino acid sequence (Mr 10,048), deduced from the cDNA of a cell cycle-specific gene. The reported biochemical identification is a prerequisite to infer the biological role of the so far undetected gene product. Initial glycohistochemical studies with sialic acid-(BSA-biotin) raised evidence for nuclear localization of sialic acid-binding sites that might reflect, at least in part, detection of this protein.

Amino Acid Sequence↗
PubMed1989

[Chronic granulocytopenia as a main symptom of T gamma-lymphocytosis].

Routine examination of a 60-year-old woman with long-lasting rheumatic complaints revealed a granulocytopenia in the differential blood count (1% stab cells, 3% segmented) with a normal total leucocyte count (4,200/microliters). It was caused by a lymphoproliferative disease of the granular lymphocytes, which may also be termed T gamma lymphocytosis because of the predominant phenotype. As the lymphocytosis in blood and bone marrow was of minor degree, the diagnosis was confirmed only by immunocytochemical and molecular-genetic demonstration of clonal expansion of the T gamma lymphocytes. The granulocytopenia gradually became more marked and recurrent infections were noted. Treatment with cyclosporin and cortisone brought about remission of the granulocytopenia.

Agranulocytosis↗
PubMed1989

Lineage- and differentiation-dependent alterations in the expression of receptors for glycoconjugates (lectins) in different human hematopoietic cell lines and low grade lymphomas.

Important biological functions and cellular recognition phenomena are supposedly governed by specific sugar-protein interactions. Human hematopoietic cell lines offer an excellent model for the study of the expression of endogenous receptors for the carbohydrate part of glycoconjugates with respect to cell lineage and modulation by differentiation. Initially, a panel of fluorescent (neo)glycoproteins was successfully employed to demonstrate cytologically the actual presence of such receptors on different cell lines: the B lymphoblast line, Daudi; the T cell lymphoblastic leukemia line, P12; the multipotent leukemic line, K562 and the promyelocytic line, HL060. Biochemical analyses were performed using affinity chromatography on supports with immobilized lactose and asialofetuin (simple or complex beta-galactosides), melibiose (alpha-galactoside), fucose, N-acetyl-D-galactosamine, maltose (alpha-glucoside), the mannose-rich yeast glycoprotein, mannan, glycopeptides containing sialic acid residues and heparin. Subsequently, sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis was used to detect cell lineage-dependent changes in theses parameters. Differentiation-dependent changes in the expression of receptors with specificity to galactose, N-acetylgalactosamine, maltose and heparin were similarly uncovered upon dimethyl sulfoxide-induced differentiation of HL60 cells. Differences in this type of cellular characteristic were also apparent for lymphoma cells from patients with various histological subtypes of lowgrade lymphomas. This initial description of lineage- and differentiation-dependent differences in various human hematopoietic cell lines and in cells from patients with lowgrade lymphomas suggests that advances in the knowledge of the composition of endogenous sugar receptors (lectins) may aid in understanding aspects of the biological behavior of hematopoietic cells and their related malignancies via participation of sugar-protein (lectin) interactions.

Cell Differentiation↗
PubMedDate not supplied

Conjugation of p-aminophenyl glycosides with squaric acid diester to a carrier protein and the use of neoglycoprotein in the histochemical detection of lectins.

The coupling of p-aminophenyl 2-acetamido-2-deoxy-3-O-beta-D- galactopyranosyl-beta-D-galactopyranoside (gal-beta 1,3-galNAc) to bovine serum albumin (BSA) was achieved by using 1,2-diethoxycyclobutene-3,4-dione (squaric acid diester) as a new coupling reagent. Two selective consequential steps afforded the desired neoglycoprotein: reaction of the p-aminophenyl group of gal-beta 1,3-galNAc with squaric acid diester gave the corresponding squaric acid amide ester, which was transformed into the BSA conjugate by coupling with the lysyl epsilon-amino group of BSA through formation of a squaric acid 1,2-bisamide. The experimental conditions for the reactions and the optimization of average were performed by using p-anisidine as model substance, the methyl group substituting for the carbohydrate part of a p-aminophenylglycoside. Neoglycoproteins have proven to be valuable tools for lectin detection. To evaluate the properties of this type of probe, the obtained neoglycoprotein with the histochemically crucial T-antigen structure was used for glycocytological and glycohistochemical studies. Three cultured human tumor cell lines and tissue sections from human breast carcinomas were chosen. Its efficiency was similar in comparison to measurements with a probe, derived by diazotization with the p-aminophenyl glycosides of gal-beta 1,3-galNAc and already shown to be a reliable marker for lectin localization in tissue sections and cultured cells.

Antigens, Tumor-Associated, Carbohydrate↗