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.

肿瘤发生的既定标志是由于肿瘤组织中糖化酶表达的变化，异常聚糖链的生物合成。随着肿瘤获得更具侵略性的表型，这些畸变变得更加明显。肿瘤细胞表面碳水化合物在许多不同癌细胞的运动性和转移中起着重要作用。此外，这些异常的聚糖中的许多是与肿瘤相关的碳水化合物抗原（TACA），并且已用于肿瘤疫苗的发育。由于大多数与TACA的细胞相互作用尚不清楚，因此迫切需要更好地表征这些事件中发生的特定分子相互作用。碳水化合物与大分子结合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“聚类”会提高这种亲和力多达一百万倍。我们已经在非常具体的模板上准备了重要的Thomsen-Friedenreich（TF）抗原（Gal？o1-3galnac ?? - O-Ser/Thr），以利用这种所谓的“簇糖苷效应”。正如上一报告所述，我们已经准备了金纳米球和量子点，这些纳米球和量子点含有糖衍生物，并报告了有关其功能的初步细节。在小鼠中与我们的金纳米球进行体内实验，重复两次，结果不同。但是，这些是由于使用与原始肿瘤构成不同的肿瘤细胞以及所用肿瘤量的误差所致。我们正在进行第四次研究，以确认原始结果，并使用仅包含用于将糖作为对照的接头单元的粒子。我们的金纳米球含有o-半乳糖，可以模仿HIV细胞融合分析中的单价半乳糖，也可以证实这些纳米构造的实用性。我们已经合成了具有生物学上重要的糖肽，并开发了新的接头技术以将其连接到黄金颗粒上。我们发现，我们需要将高度水溶性的接头添加到疏水性的肽中，以克服多种关系和聚类的物理问题，从而导致某些构建体变得不溶。在我们的量子点（QDOTS）工作中，我们表明包含含TF抗原的QDOT具有功能性，但我们需要开发技术，以消除原始设计的负电荷。这是完成的，我们现在拥有强大的接头和发光的技术，我们用来在实验室中创建这些粒子。 NCI的Chand Khanna进行进一步的成像研究表明，这些颗粒可以标记表达乳肠蛋白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进行这些研究。在过去的一年中，我们花了一半的时间没有全职研究人员，因为原始的帖子文档开发了大部分作品，突然间，NCI突然离开了NCI，并确保另一个有能力的人推迟了工作。现在，我们正在合成其他粒子，以提供我们的合作者以进一步的生物学表征。