Synthesis /Biology /Conformation Study of Tumor Antigens

肿瘤抗原的合成/生物学/构象研究

• 批准号: 6753251
• 负责人: Joseph John Barchi
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6753251
• 关键词: antigen antibody reaction; binding proteins; carbohydrates; conformation; hexosan; immunologic substance development /preparation; lectin; nanotechnology; tumor antigens

Carbohydrates chains that are covalently linked to proteins or lipids displayed on the cell surface have recently been shown to mediate many important physiological phenomena such as cell-cell or cell-matrix communication and signal transduction. As a consequence, these glycans play critical roles in many biological processes, such as inflammation, coagulation, cell motility, cell-matrix remodeling, antigenic recognition and tumor metastasis. In fact, an established hallmark of tumorigenesis is the biosynthesis of aberrant glycan chains due to changes in the expression of glycoprocessing enzymes. These aberrations become more marked as the tumor acquires a more aggressive phenotype. Many of these glycans are known tumor-associated antigens, and have been used as haptens in the development of tumor vaccines. The role that chemistry plays in this research area is threefold: 1) Defining the manner in which carbohydrates bind to proteins, 2) Unraveling the preferences of glycoprocessing enzymes for different sugar conformations and 3) Developing new synthetic techniques for the rapid and efficient preparation of oligosaccharides as tools for cellular studies. We have developed a vastly improved synthesis of an amino acid building block containing the Thomsen-Friedenreich (Tf) antigen(Galb1-3GalNAc), a glycan found in aggressive tumor cells but rarely in normal tissue, for the incorporation into peptides. In addition, we have prepared self-assembled gold nanoparticles containing this antigen to study the biological consequences of a multivalent presentation of this disaccharide. We are now planning the synthesis of multivalent constructs of Tf-containing glycopeptides derived from colon and breast cancer mucin structures as potentially highly potent immunogens for antibody production targeted to the glycosylated peptide structures. It is reasoned that since an immune response is mounted to both peptide and sugar antigens, the correct combination of the two may raise the titer of the antibody response while also stimulating a T-cell based attack. We have previously collaborated with members of the NCI on antibody binding studies of glycopeptides derived from HIV-1 and plan to continue this cooperation with this study. We have also enlisted experts from the University of Missouri to screen the multivalent constructs for inhibition of tumor cell binding to Galectin-3, a carbohydrate binding protein that is highly expressed in tumor tissue.

最近显示，与细胞表面上展示的蛋白质或脂质共价连接的碳水化合物链可以介导许多重要的生理现象，例如细胞-细胞或细胞-基质通讯和信号转导。因此，这些聚糖在许多生物过程中发挥着关键作用，例如炎症、凝血、细胞运动、细胞基质重塑、抗原识别和肿瘤转移。事实上，肿瘤发生的一个既定标志是由于糖加工酶表达的变化而生物合成异常聚糖链。当肿瘤获得更具侵袭性的表型时，这些畸变变得更加明显。许多这些聚糖是已知的肿瘤相关抗原，并已在肿瘤疫苗的开发中用作半抗原。化学在这一研究领域发挥着三重作用：1) 定义碳水化合物与蛋白质结合的方式，2) 揭示糖加工酶对不同糖构象的偏好，3) 开发新的合成技术，以快速有效地制备寡糖作为细胞研究的工具。我们开发了一种大大改进的氨基酸构建模块的合成方法，该氨基酸构建模块包含 Thomsen-Friedenreich (Tf) 抗原 (Galb1-3GalNAc)，这是一种在侵袭性肿瘤细胞中发现的聚糖，但在正常组织中很少见，用于掺入肽中。此外，我们还制备了含有这种抗原的自组装金纳米颗粒，以研究这种二糖多价呈递的生物学后果。我们现在正计划合成源自结肠癌和乳腺癌粘蛋白结构的含Tf糖肽的多价构建体，作为潜在的高效免疫原，用于生产针对糖基化肽结构的抗体。据推测，由于肽和糖抗原都会产生免疫反应，因此两者的正确组合可能会提高抗体反应的效价，同时也会刺激基于 T 细胞的攻击。我们之前曾与 NCI 成员合作开展 HIV-1 糖肽的抗体结合研究，并计划继续与这项研究合作。我们还聘请了密苏里大学的专家来筛选多价构建体，以抑制肿瘤细胞与半乳糖凝集素-3（一种在肿瘤组织中高度表达的碳水化合物结合蛋白）的结合。