Expression of lectin, interleukin-2 and histopathologic blood group binding sites in prostate cancer and its correlation with integrated optical density and syntactic structure analysis.

The binding of several biotinylated biologic probes was determined in sections of 20 surgical specimens of prostate cancer and of 21 biopsy specimens of hyperplastic prostate. Whereas neither the immunomodulatory, galactoside-specific lectin from Viscum album nor the human beta-galactoside-specific lectin (M(r) 14 kd) or its specific antibody discerned any remarkable differences, the lectin from Urtica dioica (UDA) and interleukin-2, the in vitro production of which is enhanced by this lectin, exhibited obvious preference for hyperplastic cells. In addition, the presence of binding sites for chemically synthesized blood group determinants was tested. Carcinoma cases revealed a higher percentage of binding of synthetic blood group trisaccharide H than hyperplasia cases. Due to these differences, diverse parameters, derived from measurement of integrated optical density (IOD) and from syntactic structure analysis, were correlated with the extent of binding of these biologic probes for the tumor cases. Primarily, parameters that are related to computation of a minimum spanning tree were significantly different in positive and negative cases for both UDA and interleukin-2. For the binding of blood group trisaccharide H the 5C exceeding rate, the 2CV deviation index and the distance of neighboring tumor cells with an IOD > 5 were clearly dissimilar. Our results thus suggest an extension of the panel of biologic probes for prostate cancer and substantiate the usefulness of correlations of binding of selected biologic probes to features derived from the assessment of IOD and syntactic structure analysis.

Cell type-dependent alterations of binding of synthetic blood group antigen-related oligosaccharides in lung cancer.

Blood group antigen-related oligosaccharides have been implicated in growth regulation, cell mobility control and adhesion; we are therefore interested in the localization of receptors for these oligosaccharides in tumour cells. Labelled neoglycoconjugates that carry synthetic sugar structures are suitable tools to determine: whether such binding sites are present in human lung cancer; whether structural alterations of the glycoligand part will affect extent of binding; and whether cell type-associated alterations can be detected. Sections from 121 cases of lung cancer, representing small cell and non-small cell lung carcinoma, mesothelioma and metastases from extrapulmonary primary carcinomas were used to study the binding of nine synthetic AH- and Le-related oligosaccharides. Probes with fucose-alpha 1-3/4-N-acetylglucosamine-beta 1-R, an A-like disaccharide and 3'-sulfated galactose as ligand appear to bind less well to small cell than to non-small cell lung cancer cases, whereas Lec-disaccharide distinguishes mesothelioma from metastatic carcinoma. The latter ligand, A-like disaccharide and H (type III)-like trisaccharide exhibit evident cell type-associated differences in extent of binding. Thus, tailor-made neoglycoconjugates constitute a promising class of histopathological tools that warrants further study.

Reverse lectin histochemistry: design and application of glycoligands for detection of cell and tissue lectins.

Plant and invertebrate lectins are valuable cyto- and histological tools for the localization of defined carbohydrate determinants. The well-documented ubiquitous occurrence of sugar receptors encourages functional considerations. Undoubtedly, analysis of the presence of vertebrate lectins in tissues and cells is required to answer the pertinent and tempting question on the physiological relevance of protein (lectin)-carbohydrate recognition in situ. Carrier-immobilized glycoligands, derived from custom-made chemical synthesis, enable the visualization of respective binding sites. Histochemically inert proteins or synthetic polymers with appropriate functional groups are suitable carrier molecules for essential incorporation of ligand and label. The resulting neoglycoconjugates can track down tissue receptors that are neither impaired by fixation procedures nor blocked by endogenous high-affinity ligands. Lectins, especially the receptors of the tissue under investigation (endogenous lectins), and appropriately tailored immobilized glycoligands or lectin-specific antibodies (when available) are complementary tools to test the attractive hypothesis that diverse, functionally relevant glycobiological processes within or between cells are operative. Concomitant evaluation of both sides of lectin histochemistry, namely lectins as tools and lectins as functionally important molecules in situ, will indubitably render desired progress amenable in our often still fragmentary understanding of the importance of tissue lectin and glycoconjugate expression and its regulation.

Synthesis of polymeric neoglycoconjugates based on N-substituted polyacrylamides.

Several types of polymeric glycoconjugates, N-substituted polyacrylamides, have been synthesized by the reaction of activated polymers with omega-aminoalkylglycosides: (i) (carbohydrate-spacer)n-polyacrylamide, 'pseudopolysaccharides'; (ii) (carbohydrate-spacer)n-phosphatidylethanolaminem-polyacrylamide, neoglycolipids, derivatives of phosphatidylethanolamine; (iii) (carbohydrate-spacer)n-biotin-polyacrylamide, biotinylated probes; (iv) (carbohydrate-spacer)n-polyacrylamide-(macroporous glass), affinity sorbents based on macroporous glass, covalently coated with polyacrylamide. An almost quantitative yield in the conjunction reaction makes it possible to insert in the conjugate a predetermined quantity of the ligand(s). Pseudopolysaccharides proved to be a suitable form of antigen for activation of polystyrene and poly(vinyl chloride) plates (ELISA) and nitrocellulose membranes (dot blot), being advantageous over traditional neoglycoproteins. Polyvalent glycolipids insert well in biological membranes: their physical properties, particularly solubility, can be changed in a desired direction. Biotinylated derivatives were used as probes for detection and analysis of lectins.

Oligosaccharide-binding molecules on the surface of human hemopoietic and lymphoid cells.

High oligosaccharide specificity for binding carbohydrate probes (biotinylated polyacrylamide with carbohydrates attached) with human hemopoietic and lymphoid cells is shown. Of 15 probes studied those bearing blood group trisaccharides, A and B, bound most intensely. In addition, transformed (leukemic and lymphoid) cells interacted more strongly than normal ones.