Centre for Advanced Macromolecular Design (CAMD), School of Chemistry , University of New South Wales , Sydney NSW 2052 , Australia.
Australia Nuclear Science and Technology Organisation , Lucas Heights , NSW 2234 , Australia.
Biomacromolecules. 2019 Jan 14;20(1):273-284. doi: 10.1021/acs.biomac.8b01406. Epub 2018 Dec 14.
Glycopolymer-coated nanoparticles have attracted significant interest over the past few years, because of their selective interaction with carbohydrate receptors found on the surface of cells. While the type of carbohydrate determines the strength of the ligand-receptor interaction, the presentation of the sugar can be highly influential as the carbohydrate needs to be accessible in order to display good binding. To shine more light on the relationship between nanoparticle structure and cell uptake, we have designed several micelles based on fructose containing block copolymers, which are selective to GLUT5 receptors found on breast cancer cell lines. The polymers were based on poly-d,l-lactide (PLA), poly(2-hydroxyethyl) acrylate (PHEA), and poly(1- O-acryloyl-β-d-fructopyranose) (P[1- O-AFru]). A set of six micelles was synthesized based on four fructose containing micelles (PLA- b-P[1- O-AFru], PLA- b-P[1- O-AFru], PLA- b-P[1- O-AFru-c-HEA], PLA- b-PHEA- b-P[1- O-AFru]) and two neutral controls (PLA- b-PHEA and PLA- b-PHEA). SAXS analysis revealed that longer hydrophilic polymers led to lower aggregation numbers and larger hydrophilic shells, suggesting more glycopolymer mobility. Cellular uptake studies via flow cytometry and confocal laser scanning microscopy (CLSM) confirmed that the micelles based on PLA- b-P[1- O-AFru] show, by far, the highest uptake by MCF-7 and MDA-MB-231 breast cancer cell lines while the uptake of all micelles by RAW264.7 cell is negligible. The same micelle displayed was far superior in penetrating MCF-7 cancer spheroids (three-dimensional (3D) model). Taking the physicochemical characterization obtained by SAXS and the in vitro results together, it could be concluded that the glycopolymer chains on the surface of micelle must display high mobility. Moreover, a high density of fructose was found to be necessary to achieve good biological activity as lowering the epitope density led immediately to lower cellular uptake. This work showed that it is crucial to understand the micelle structure in order to maximize the biological activity of glycopolymer micelles.
糖聚合物涂层纳米粒子在过去几年中引起了极大的关注，因为它们与细胞表面的碳水化合物受体具有选择性相互作用。虽然碳水化合物的类型决定了配体-受体相互作用的强度，但糖的呈现方式也具有很大的影响力，因为碳水化合物需要可及才能显示良好的结合。为了更深入地了解纳米颗粒结构与细胞摄取之间的关系，我们设计了几种基于含有果糖的嵌段共聚物的胶束，这些胶束对乳腺癌细胞系上的 GLUT5 受体具有选择性。这些聚合物基于聚-d,l-乳酸（PLA）、聚（2-羟乙基）丙烯酸酯（PHEA）和聚（1-O-丙烯酰基-β-d-呋喃果糖）（P[1-O-AFru]）。基于四种含有果糖的胶束（PLA-b-P[1-O-AFru]、PLA-b-P[1-O-AFru]、PLA-b-P[1-O-AFru-c-HEA]、PLA-b-PHEA-b-P[1-O-AFru]）和两种中性对照物（PLA-b-PHEA 和 PLA-b-PHEA）合成了一组六种胶束。小角 X 射线散射（SAXS）分析表明，较长的亲水性聚合物导致较低的聚集数和较大的亲水性壳，表明糖聚合物的迁移性更高。通过流式细胞术和共聚焦激光扫描显微镜（CLSM）进行的细胞摄取研究证实，基于 PLA-b-P[1-O-AFru]的胶束迄今为止显示出 MCF-7 和 MDA-MB-231 乳腺癌细胞系的摄取率最高，而 RAW264.7 细胞对所有胶束的摄取可以忽略不计。同一胶束在穿透 MCF-7 癌症球体（三维（3D）模型）方面表现出色。将 SAXS 获得的理化特性和体外结果结合起来，可以得出结论，胶束表面的糖聚合物链必须具有高迁移率。此外，发现需要高浓度的果糖才能达到良好的生物活性，因为降低表位密度会立即导致细胞摄取减少。这项工作表明，为了最大限度地提高糖聚合物胶束的生物活性，了解胶束结构至关重要。
