Increase of MAL-II Binding Alpha2,3-Sialylated Glycan Is Associated with 5-FU Resistance and Short Survival of Cholangiocarcinoma Patients

Background and objectives: Sialylation plays important roles in tumor progression. Our present study aimed to demonstrate the alteration of sialylation and its role in cholangiocarcinoma (CCA). Materials and Methods: The α2,3- and α2,6-sialylation in CCA tissue was analyzed by lectin-histochemistry using Maackia amurensis lectin-II (MAL-II) and Sambucus nigra agglutinin (SNA). CCA cell lines were treated with the pan-sialylation inhibitor 3Fax-peracetyl-Neu5Ac (3F-Sia) followed by proliferation and chemosensitivity assays. Results: MAL-II binding α2,3-Sialylated Glycan (MAL-SG) and SNA binding α2,6-Sialylated Glycan (SNA-SG) were both elevated in CCA compared with hyperplastic/dysplastic (HP/DP) and normal bile ducts (NBD). The positive staining for MAL-SG or SNA-SG were found in 82% (61/74) of the CCA cases. Higher expression of MAL-SG in CCA was associated with shorter survival of the patients. The median survival of patients with high and low MAL-SG were 167 and 308 days, respectively, with overall survival of 233 days, suggesting the involvement of MAL-SG in CCA progression. MAL-SG expression of CCA cell lines was markedly decreased after treatment with 3F-Sia for 48 to 72 h. While proliferation of CCA cells were not affected by 3F-Sia treatment, their susceptibility to 5-fluorouracil (5-FU) was significantly enhanced. These results suggest that sialylation is involved in the development of 5-FU resistance and the sialylation inhibitor 3F-Sia can be used as a chemosensitizer for CCA. Conclusions: Sialylation is critically involved in the development of chemoresistance of CCA, and sialylation inhibitors may be used as a chemosensitizer in CCA treatment.

The content of immunomodulatory glycoepitopes in seminal plasma glycoproteins of fertile and infertile men

According to a concept of fetoembryonic defence, protein–carbohydrate interaction may be involved in the regulation of maternal immunity that prevents rejection of allograft spermatozoa, embryo and fetus. In the present study we focussed on the evaluation of the expression of glycoepitopes that may be of crucial importance in this process: LewisY (LeY) and LewisX (LeX) as well as terminal sialylation. Polyacrylamide gel electrophoresis with sodium dodecyl sulphate was used to separate seminal plasma samples of fertile (n=10) and infertile (n=103) men; these were then probed with lectins specific to fucose (Lotus tetragonolobus agglutinin and Ulex europaeus agglutinin) and sialic acid (Sambucus nigra agglutinin and Maackia amurensis agglutinin). Differential expression of α2,3-bound sialic acid was found in six out of seven analysed bands, whereas differences in the other analysed glycoepitopes were found in fewer numbers of bands. Mass spectrometry analysis focussed on the identification of proteins carrying glycans with immunomodulatory epitopes, including fibronectin, lactoferrin, clusterin, zinc-α2-glycoprotein, prostate acid phosphatase and prostate-specific antigen; these should be submitted to further detailed analysis.

LECTIN-HISTOCHEMICAL REGULARITIES OF DIFFERENTIATION OF THE HUMAN PAROTID GLAND EPITHELIAL GERMS

Glycopolymer compounds make up structural and functional basis of cells and tissues of a living organism. The necessity of anatomical-lectinohistochemical examination of the parotid gland in early prenatal period of ontogenesis is substantiated, as the evidences concerning its topography are fragmentary and not systematized, and certain aspects of its ontogenesis are disputable. 35 human embryos and pre-fetuses aged from 21 days to 12 weeks of intrauterine development were examined. Glycopolymers were found by means of treatment of serial sections with lectins conjugated with horseradish peroxidase. The dynamics of prenatal morphogenesis of the embryos and pre-fetuses of the 4th-12th week of embryogenesis expression of glycopolymers – lectinreceptors on the surface of cells, in the cytoplasm and on the basal membrane of the parotid gland epithelial germs and the human oral cavity with its derivatives by re-distribution of glycopolymers are similar, which can be the evidence of ectodermal source of the parotid gland epithelial germ. Immersion of the epithelial cells of the buccal-alveolar pockets into the lower adjacent mesenchyme with the formation of primary parotid gland germs in embryos with 11,0-12,5 mm of PCL and their transformation into the epithelial taeniae is associated with accumulation of sialic glycopolymers (N-acetyl neuraminic acid), N-acetyl-D-glucosamine – specific to Wheat germ agglutinin (WGA) and Sambucus nigra agglutinin (SNA); N-acetyl-2-desoxy-2-amino-D-glucopyranose, screened by sialic acid of ß-D-galactose and α-L-fucose – specific to Helix pomatia (edible snail) agglutinin (HPA), Rhizoctonia solani agglutinin (RCA) and Laburnum anagyroides (Golden Rain shrub) agglutinin (LABA) respectively. These glycopolymers are present during the first 12 weeks both on the cytolemma of the cells of the parotid gland epithelial germ and in their cytoplasm. The results of lectin-histochemical examination of the early prenatal ontogenesis of the parotid gland can form the basis for the work of laboratories dealing with screening of morphological material in order to assess the degree of maturation and prognosis of fetus viability and diagnostics of deviations from normal development.

Increased Sialylation of Anti-Thomsen-Friedenreich Antigen (CD176) Antibodies in Patients with Gastric Cancer: A Diagnostic and Prognostic Potential

Aim. To study whether alterations in the sialylation of antibodies (Ab) specific to the Thomsen-Friedenreich (TF) glycotope have a diagnostic and prognostic potential in gastric cancer.Methods. Serum samples were taken from patients with gastric carcinoma(n=142)and controls(n=61). The level of TF-specific antibodies and their sialylation was detected using ELISA with synthetic TF-polyacrylamide conjugate as antigen and sialic acid-specificSambucus nigra agglutinin(SNA).Results. The level of TF-specific IgM was significantly decreased in cancer compared with controls(P≤0.001). Cancer patients showed a higher level of SNA binding to anti-TF IgM and IgA(P≤0.001)irrespective of disease stage, tumor morphology, and gender. Changes in the SNA/Ab index demonstrated moderate sensitivity (66–71%) and specificity (60–73%) for stomach cancer. The best diagnostic accuracy (100%) was achieved in 29% patients with high SNA binding and low anti-TF IgM level. This subset of patients demonstrated the poorest survival.Conclusion. Our findings are the first evidence that the increased sialylation of TF-specific Abs combined with a low level of anti-TF IgM is strongly linked to gastric cancer and patients survival, which can be used as a novel biomarker for cancer detection and prognosis.