Ciołczyk-Wierzbicka Dorota, Gil Dorota, Hoja-Łukowicz Dorota, Lityńska Anna, Laidler Piotr
Institute of Medical Biochemistry, Medical College, Jagiellonian University, Kraków, Poland.
Acta Biochim Pol. 2002;49(4):991-8.
Expression of N-cadherin an adhesion molecule of the cadherin family, in tumor cells is associated with their increased invasive potential. Many studies suggested the role of N-linked oligosaccharides as important factors that contribute to metastasis by influencing tumor cell invasion and adhesion. N-cadherin is a heavily glycosylated protein. We have analysed the carbohydrate profile of this protein synthesized in human melanoma cell lines: WM35 from the primary tumor site and WM239, WM9, and A375 from different metastatic sites. N-cadherin was immunoprecipitated with anti-human N-cadherin polyclonal antibodies. Characterisation of its carbohydrate moieties was carried out by SDS/PAGE electrophoresis and blotting, followed by immunochemical identification of the N-cadherin polypeptides and analysis of their glycans using highly specific digoxigenin or biotin labelled lectins. The positive reaction of N-cadherin from the WM35 cell line with Galanthus nivalis agglutinin (GNA), Datura stramonium agglutinin (DSA) and Sambucus nigra agglutinin (SNA) indicated the presence of high-mannose type glycans and biantennary complex type oligosaccharides with alpha2-6 linked sialic acid. N-cadherin from WM239, WM9, and A375 cell lines gave a positive reaction with Phaseolus vulgaris leukoagglutinin (L-PHA) and lotus Tetragonolobus purpureas agglutinin (LTA). This indicated the presence of tri- or tetra-antennary complex type glycans with alpha-fucose. In addition, N-cadherin from WM9 (lymphomodus metastatic site) and A375 (solid tumor metastatic site) contained complex type chains with alpha2-3 sialic acid (positive reaction with Maackia amurensis agglutinin--MAA). The results demonstrated that N-glycans of N-cadherin are altered in metastatic melanomas in a way characteristic for invasive tumor cells.
钙黏蛋白家族的一种黏附分子N-钙黏蛋白在肿瘤细胞中的表达与其侵袭潜能的增加有关。许多研究表明，N-连接寡糖作为重要因素，通过影响肿瘤细胞的侵袭和黏附作用来促进转移。N-钙黏蛋白是一种高度糖基化的蛋白质。我们分析了在人黑色素瘤细胞系中合成的这种蛋白质的糖谱：来自原发性肿瘤部位的WM35以及来自不同转移部位的WM239、WM9和A375。用抗人N-钙黏蛋白多克隆抗体对N-钙黏蛋白进行免疫沉淀。通过SDS/PAGE电泳和印迹对其糖部分进行表征，随后对N-钙黏蛋白多肽进行免疫化学鉴定，并使用高度特异性的地高辛配基或生物素标记的凝集素分析其聚糖。来自WM35细胞系的N-钙黏蛋白与雪花莲凝集素（GNA）、曼陀罗凝集素（DSA）和黑接骨木凝集素（SNA）呈阳性反应，表明存在高甘露糖型聚糖和带有α2-6连接唾液酸的双天线复合型寡糖。来自WM239、WM9和A375细胞系的N-钙黏蛋白与菜豆白细胞凝集素（L-PHA）和紫花百脉根凝集素（LTA）呈阳性反应。这表明存在带有α-岩藻糖的三或四天线复合型聚糖。此外，来自WM9（淋巴结转移部位）和A375（实体瘤转移部位）的N-钙黏蛋白含有带有α2-3唾液酸的复合型链（与黑果枸杞凝集素——MAA呈阳性反应）。结果表明，N-钙黏蛋白的N-聚糖在转移性黑色素瘤中以侵袭性肿瘤细胞特有的方式发生改变。
