Novel Carboxylated Glycans in Cell Adhesion

描述(申请人提供)：恶性肿瘤涉及细胞的生长、运动和转移。调节这些功能的关键细胞检查点之一是分泌的胞浆分子两性霉素与细胞表面晚期糖基化终产物受体(RAGE)的结合。我们发现这种结合涉及到我们发现的新的糖链。这项建议探索了介导这些相互作用的多糖的结构和功能。我们已经确定了一种新型的羧化N-连接低聚糖，它特别富含于内皮细胞、胚胎神经元和癌细胞中。我们的生化和免疫学证据表明，该抗原含有与糖链相连的二羧化氨基酸。这些新的多糖介导内皮/白细胞结合、体内的腹膜炎症和体外的轴突生长。羧化多糖直接与四种蛋白质结合：两性蛋白、膜联蛋白-I和S 100A8/A9，以及S100A12，它们以不同的方式与炎症、感染性休克、肿瘤生长或转移有关。我们发现RAGE N连接的糖链含有羧酸盐，它们介导了两性激素受体的结合以及它们引发的多种细胞内信号事件中的一些。为了了解羧化多聚糖在这一复杂过程中的作用，我们建议： 1.建立牛RAGE和神经母细胞瘤细胞上羧化多聚糖的详细结构。 2.从配体结合和细胞内信号转导的角度，确定羧化多聚糖在确定RAGE病理生理功能中的意义。 3.评估羧化多聚糖在体内外介导两性激素相互作用导致肿瘤生长、侵袭和转移中的作用。对这些新的多聚糖的结构及其对肿瘤生长和转移的影响的基本了解可能会增加对这些病理的理解的重要维度，并可能导致新的治疗方法来阻断它们。

DESCRIPTION (provided by applicant): Malignancy involves cellular growth, movement, and metastasis. One of the key cellular check-points regulating these features is the binding of a secreted cytosolic molecule called amphoterin to the cell surface receptor for advanced glycation end products (RAGE). We found that this binding involves novel glycans that we discovered. This proposal explores the structure and function of the glycans that mediate these interactions. We have identified a new type of carboxylated N-linked oligosaccharide that is especially enriched in endothelial cells, embryonic neurons and cancer cells. Our biochemical and immunological evidence indicates that the antigen contains di-carboxylated amino acids amide-linked to the sugar chains. These novel glycans mediate endothelium/leukocyte binding, and intraperitoneal inflammation in vivo and neurite outgrowth in vitro. The carboxylated glycans directly bind to four proteins: amphoterin, annexin-I and S 100A8/A9, and S100A12, which have been linked in various ways to inflammation, septic shock, tumor growth or metastasis. We found that RAGE N-linked sugar chains contain the carboxylates and that they mediate amphoterin-RAGE binding and some of the multiple intracellular signaling events they ignite. To understand the role of the carboxylated glycans in this complex process, we propose to: 1. Establish the detailed structure of the carboxylated glycans on bovine RAGE and in neuroblastoma cells. 2. Determine the significance of carboxylated glycans in defining the pathophysiological functions of RAGE, in terms of ligand binding and intracellular signaling. 3. Assess the role of carboxylated glycans in mediating amphoterin-RAGE interactions in vitro and in vivo that lead to tumor growth, invasion, and metastasis.The fundamental understanding of the structure of these novel glycans together with their effects on tumor growth and metastasis are likely to add an important dimension to the understanding of these pathologies and may lead to novel therapeutic approaches to block them.