NMR Group Project: Preparation and Properties of Novel Multivalent Nanoparticles

肿瘤发生的一个既定标志是异常聚糖链的生物合成 这是由于肿瘤组织中糖加工酶表达的变化。这些像差 随着肿瘤获得更具侵袭性的表型而变得更加显著。肿瘤细胞表面 碳水化合物在许多不同癌症的运动和转移中起重要作用 细胞此外，许多这些异常聚糖是肿瘤相关的碳水化合物抗原 （TACA），并已用于肿瘤疫苗的开发。因为大多数的细胞 与TACA的相互作用还没有得到很好的理解，迫切需要更好地 表征这些事件期间发生的特定分子相互作用。一个特征 碳水化合物与大分子结合的概念， 多价性：碳水化合物与蛋白质的结合非常弱， 单体的聚集使这种亲和力提高了一百万倍之多。 我们制备了重要的转铁蛋白（Tf）抗原 （Gal（beta）1 - 3GalNAc（alpha）-O-Ser/Thr），以利用这一点 即所谓簇糖苷效应。如上一份报告所述，我们 制备了含糖衍生物的金自组装纳米球和量子点， 报告了其功能的初步细节。用我们的黄金做的体内实验 将小鼠中的纳米球重复两次，结果不同。然而，这些都是由 使用一种基因组成与原始细胞不同的肿瘤细胞， 使用的肿瘤量错误。我们对金进行了进一步的体外表征， 粒子，并发现它们的行为不同于单价糖分子。一个大的体内 一项研究得出了相互矛盾但极具挑衅性的结果， 相对于对照（仅连接体）纳米颗粒测试的颗粒。我们似乎可以 在体内抑制原发性肿瘤生长，但我们可能用 更大的流体动力体积。在过去的一年里，集中研究了 了解相互矛盾的体内数据。我们认为我们已经解决了这个问题， 检查糖的尺寸分布、表面密度和连接体技术， 纳米粒子我们已经表明，一个特定的立体化学的糖是有害的 粒子自组装，并解决了这个问题，降低表面密度的 糖类。我们还表明，单糖的比表面密度可以 促进或抑制HIV附着于某些哺乳动物细胞。我们正在优化这个 技术，以找到最强大的粒子在体内应用。在上次报告中， 报道了粘蛋白糖肽的合成，并开发了新的接头技术来连接这些 黄金颗粒。我们今年发现，连接器技术不是合成的， 由于未预料到的聚集效应，这是可行的。我们准备了一个更健壮的链接器 并制备了4种糖肽和一种对照肽，它们与金纳米颗粒连接。 进行表征，颗粒均匀。我们已经开始接种疫苗 我们的合作者Kate Rittenhouse Olsen在八只小鼠身上进行了两次单独的实验， 含有MUC4重复单元糖肽的颗粒。此外，我们正研究 TF抗原的性质通过制备颗粒与氨基酸-接头技术进行比较 与那些简单的连接器和连接器单独。我们对未来的命运感到非常兴奋 这是疫苗接种研究的一个重要方面，因为这将是一个向宿主呈递抗原的新平台。

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 TACAs 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(beta)1-3GalNAc(alpha)-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 have done further in vitro characterization of the gold particles and found them to act differently than monovalent sugar molecules. A large in vivo study has yielded conflicting but highly provocative results with varying concentrations of particles being tested against control (linker-only) nanoparticles. We seem to be able to inhibit primary tumor growth in vivo, but we possibly promote metastasis with particles of larger hydrodynamic volume. In the past year, a concentrated research effort was mounted to understand the conflicting in vivo data. We feel we have solved this problem by closely examining the size distribution, surface density of sugars and the linker technology of the nanoparticles. We have shown that a specific stereochemistry of the saccharide is detrimental to particle self assembly and solved this problem with reduced surface density of the carbohydrate. We have also shown that specific surface densities of simple sugars can either promote or inhibit the attachment of HIV to certain mammalian cells. We are optimizing this technology to find the most robust particles for in vivo applications. In the last report we reported synthesis of mucin glycopeptides and developed new linker technology to attach these to gold particles. We discovered this year that that linker technology was not synthetically feasible due to unanticipated aggregation effects. We have prepared a much more robust linker and prepared 4 glycopeptides plus a control peptide that were linked to gold nanoparticles. Characterizations were performed and the particles were uniform. We have started a vaccination protocol with our collaborator Kate Rittenhouse Olsen on eight mice with two separate particles containing MUC4 repeating unit glycopeptides. In addition, we are exploring the nature of the TF antigen by preparing particles with amino acid-linker technology to compare with those of simple saccharides and linker alone. We are very excited about the fate of the vaccination studies since this would be a novel platform to present antigen to a host.