MON-LB85 Aberrant Glycan Expression Changes With the Phenotype of Follicular Thyroid Tumours

Glycosylation is the most common post-translational modification of proteins and plays an important role in cell communication, interaction and adhesion. Aberration of glycosylation is a hallmark of cancer cells and plays an important role in oncogenesis and cancer progression including metastasis1. One of the markers of aberrant glycosylation (O-linked) is the binding of the lectin Helix pomatia agglutinin (HPA), and this has been shown in a wide range of human cancers2, especially in tumours with a more aggressive phenotype. To study the alteration in cellular glycosylation, detected by lectin Helix pomatia agglutinin (HPA) binding in various phenotypes of follicular thyroid tumours, ranging from adenoma to carcinoma and metastatic follicular thyroid cancers. Lectin histochemistry was performed on archival paraffin wax-embedded specimens of 6 follicular adenomas, 10 minimally invasive follicular carcinomas, 13 widely invasive follicular cancers and 4 metastatic follicular thyroid cancers. For positive controls, sections of rat kidney were used, which shows strong and characteristic HPA labelling were included in each labelling experiment. For negative controls, the lectin was omitted and the specificity of binding was confirmed by incubating the sections with HPA in the presence of 0·1-mol/l GalNAc. Sections were scored as positive when 5% or more of the cancer cells labelled positive and scored as negative when less than 5% labelled positive for HPA binding. Assessments of HPA binding were performed by two observers who were blinded to the identity of the sample, and their results were compared. Positive labelling was seen in 20% of adenomas, 60% of minimally invasive carcinomas, 77% of widely invasive carcinomas and 100% of metastatic carcinomas (p<0.05). In the minimally invasive carcinoma group, all tumours that showed vascular invasion showed positive HPA labelling, whereas only 20% of patients with capsular invasion showed positivity. We speculate that as the phenotype of the thyroid tumours changes from benign to the malignant phenotype, the glycan expressions change. However, the underlying molecular mechanisms leading to this change needs to be further investigated. References:1. Magalhães, A., Duarte, H.O. & Reis, C.A. 2017, “Aberrant Glycosylation in Cancer: A Novel Molecular Mechanism Controlling Metastasis”, Cancer Cell, vol. 31, no. 6, pp. 733-735.2. Parameswaran, R., Sadler, G. & Brooks, S. 2011, “Helix pomatia Agglutinin Binding Glycoproteins in Thyroid Tumors”, World Journal of Surgery, vol. 35, no. 10, pp. 2219-2227.3. Parameswaran, R., Tan, W.B., Nga, M.E., Soon, G.S.T., Ngiam, K.Y., Brooks, S.A., Sadler, G.P. & Mihai, R. 2018, “Binding of aberrant glycoproteins recognizable by Helix pomatia agglutinin in adrenal cancers”, BJS open, vol. 2, no. 5, pp. 353-359.

Lectinhistochemical staining of granuloma induced by bacillus Calmette-Guerin in Piaractus mesopotamicus

ABSTRACTObjetive. This study was conducted to evaluate, by means of lectinhistochemistry (LHC), the expression of carbohydrates in granulomas induced by the bacillus Calmette-Guerin (BCG) in muscle tissue of Piaractus mesopotamicus after 33 days. Material and methods. Histological sections with 3 μm thick were incubated with the following lectins :WGA (Wheat germ agglutinin), DBA (Dolichos biflorus agglutinin) and HPA (Helix pomatia agglutinin), and the results were evaluated by light microscopy. Results. Acid fast bacilli were stained by Ziehl Neelsen (ZN) and strong labeled by WGA in the cytoplasm of macrophages. Labeling with DBA was intense in fibroblasts and weak in macrophages. On the other hand, HPA binding was stronger in macrophages, especially in those that were in close contact with epithelioid cells, without evidence of binding to fibroblasts. The epithelioid cells were not labeled by the used lectins, but they were identified by Hematoxilin-Eosin (HE). The lectins labeled specific type saccharides in glycoproteins, as N-acetylglucosamine present in bacilli and macrophages, as well as N-acetyl-galactosamine in macrophages. The control group showed no inflammation or lectin binding. Conclusions. This technique may be useful in identifying receptors for WGA, DBA and the HPA lectins in epithelioid granuloma induced by BCG in P. mesopotamicus

Glycocalyx characterisation and glycoprotein expression of Sus domesticus epididymal sperm surface samples

The sperm surface is covered with a dense coating of carbohydrate-rich molecules. Many of these molecules are involved in the acquisition of fertilising ability. In the present study, eight lectins (i.e. Arachis hypogae (peanut) agglutinin (PNA), Lens culimaris (lentil) agglutinin-A (LCA), Pisum sativum (pea) agglutin (PSA), Triticum vulgari (wheat) germ agglutinin (WGA), Helix pomatia agglutinin (HPA), Phaseolus vulgaris (red kidney bean) leucoagglutinin (PHA-L), Glycine max (soybean) agglutinin (SBA) and Ulex europaeus agglutinin I (UEA-I)) were investigated to identify changes in the nature and localisation of glycoproteins in boar spermatozoa migrating along the epididymal duct. Complementary procedures included measurement of global lectin binding over the surface of the viable sperm population by flow cytometry, analysis of lectin localisation on the membrane of individual spermatozoa using fluorescence microscopy and the electrophoretic characterisation of the major sperm surface glycoprotein receptors involved in lectin binding. A significant increase was found in sperm galactose, glucose/mannose and N-acetyl-d-glucosamine residues distally in the epididymis. Moreover, the sperm head, cytoplasmic droplet and midpiece were recognised by most of the lectins tested, whereas only HPA and WGA bound to the principal piece and end piece of the sperm tail. Fourteen sperm surface proteins were observed with different patterns of lectin expression between epididymal regions. The sperm glycocalyx modifications observed in the present study provide an insight into the molecular modifications associated with epididymal maturation, which may be correlated with the degree of maturation of ejaculated spermatozoa.