NMR Group Project: Preparation and Properties of Novel M

NMR 课题组项目：Novel M 的制备及性能

• 批准号: 7291828
• 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/7291828
• 关键词: NMR; Group; Project; Preparation; Properties

An established hallmark of tumorigenesis is the biosynthesis of aberrant glycan chains due to changes in the expression of glycoprocessing enzymes in tumor tissue. These aberrations become more marked as the tumor acquires a more aggressive phenotype. Tumor cell-surface carbohydrates play important roles in the motility and metastasis of many different cancer cells. In addition, many of these aberrant glycans are tumor-associated carbohydrate antigens (TACA) and have been used in the development of tumor vaccines. Since most of the cellular interactions with TACA's are not well understood, there is an urgent need to better characterize the specific molecular interactions that occur during these events. One feature of carbohydrate binding to macromolecules that is well understood is the concept of multivalency: Monomer carbohydrates bind to proteins very weakly while "clustering" of a monomer raises this affinity as much as a million-fold. We have prepared the important Thomsen-Friedenreich (Tf) antigen (Gal?O1-3GalNAc??-O-Ser/Thr) on very specific templates to take advantage of this so-called "cluster glycoside effect". As mentioned in the last report, we have prepared gold self-assembled nanospheres and quantum dots containing sugar derivative and reported preliminary details on their function. The in vivo experiments with our gold nanospheres in mice were repeated twice with varying results. However, these were caused by the use of a tumor cells that had had a different genetic makeup than the original and an error in the amount of tumor used. We are proceeding with a 4th study to confirm the original results along with using particles that contain simply the linker unit used to attach the sugar as a control. Our gold nanospheres containing ?O-galactose can mimic monovalent galactose in HIV cell fusion assays, also confirming the utility of these nano-constructs. We have synthesized biologically important glycopeptides and developed new linker technology to attach these to gold particles. We discovered that we need to add highly water soluble linkers to peptides that are hydrophobic to overcome the physical problems with the creation of multivalency and clustering that causes some constructs to become insoluble. In our quantum dots (qdots) work, we showed that contain Tf antigen-containing Qdots are functional but we needed to develop technology that removed the negative charge on our original design. This was accomplished and we now have a robust linker and luminescent-enhancing technology that we use to create these particles de novo in the lab. Further imaging studies with Chand Khanna at NCI have shown that these particles can label tumor cells that express galectin-3 and possible cause these cells to become apoptotic. We are continuing these studies with several collaborators. In this past year, we spent half of the time without a full time researcher since the original post doc who developed most of the work left the NCI suddenly and the timing to secure another able fellow delayed the work. We are now synthesizing additional particles to supply our collaborators for further biological characterization.

肿瘤发生的一个公认的标志是由于肿瘤组织中糖处理酶表达的变化而导致异常糖链的生物合成。随着肿瘤获得更具侵袭性的表型，这些像差变得更加明显。肿瘤细胞表面的碳水化合物在许多不同癌细胞的运动和转移中起着重要作用。此外，这些异常多糖中的许多是肿瘤相关碳水化合物抗原(TACA)，并已被用于肿瘤疫苗的开发。由于大多数细胞与TACA的相互作用还不是很清楚，因此迫切需要更好地描述在这些事件期间发生的特定分子相互作用。碳水化合物与大分子结合的一个众所周知的特征是多价性的概念：单体碳水化合物与蛋白质的结合非常弱，而单体的“聚集”使这种亲和力提高了一百万倍。我们在非常特殊的模板上制备了重要的Thomsen-Friedenreich(Tf)抗原(Gal？O1-3GalNAc？？O-Ser/Thr)，以利用这种所谓的“簇状糖苷效应”。正如上一份报告中提到的，我们已经制备了含有糖衍生物的金自组装纳米球和量子点，并报告了它们的功能的初步细节。用我们的金纳米球在小鼠身上进行的体内实验重复了两次，结果各不相同。然而，这些是由于使用了与原始细胞基因组成不同的肿瘤细胞，以及使用的肿瘤数量错误造成的。我们正在进行第四项研究，以证实最初的结果，同时使用只包含用于连接糖的连接单元的颗粒作为对照。我们的含有O-半乳糖的金纳米球在HIV细胞融合分析中可以模拟单价半乳糖，也证实了这些纳米结构的实用性。我们已经合成了具有生物重要性的糖肽，并开发了新的连接物技术将它们连接到金粒子上。我们发现，我们需要向疏水的多肽中添加高度水溶性的连接物，以克服导致某些结构变得不可溶的多价性和聚集性的物理问题。在我们的量子点(Qdots)工作中，我们展示了含有转铁蛋白抗原的量子点是有功能的，但我们需要开发技术来消除原始设计上的负电荷。这已经完成了，我们现在有了一个强大的连接器和发光增强技术，我们使用它来在实验室中从头开始创造这些粒子。与NCI的Chand Khanna进行的进一步成像研究表明，这些颗粒可以标记表达Galectin-3的肿瘤细胞，并可能导致这些细胞凋亡。我们正在与几位合作者继续这些研究。在过去的一年里，我们有一半的时间没有全职研究人员，因为开发大部分工作的原始博士后突然离开了NCI，而寻找另一个有能力的人的时机推迟了工作。我们现在正在合成更多的颗粒，为我们的合作者提供进一步的生物学特性。