Adaptable Polymer Micelles for Tumor Targeting

描述（由申请人提供）：聚合物胶束已广泛用于递送水溶性差的药物。尽管它们具有很好的特性，但它们还没有完全发展成为抗癌药物靶向递送的载体。这主要是由于缺乏对聚合物胶束在静脉注射后的体内行为的了解。物理上自组装的聚合物胶束在血液中不稳定，但目前还没有系统的研究。本研究的重点是了解聚合物胶束与血液成分之间的相互作用，以开发一类新的聚合物胶束，用于临床应用的靶向递送抗癌药物。这项研究的长期目标是开发适应性强的聚合物胶束，这种胶束在血液中是稳定的，但会被肿瘤部位丰富的酶解离。这个项目的假设是，血液中聚合物胶束的稳定性是成功治疗肿瘤的先决条件。只有稳定的聚合物胶束才有机会靶向肿瘤并在治疗有效水平上提供抗肿瘤药物。该项目的具体目标是：(1)开发适应性聚合物胶束；(2)检测胶束在血液中的稳定性；(3)阐明胶束-细胞相互作用；(4)表征胶束在体内的命运，研究载药胶束的抗肿瘤活性。用于肿瘤治疗的两种药物是紫杉醇和吉非替尼，它们具有相似的疏水性。两种药物对的协同作用有望产生较好的抗肿瘤效果。适应性聚合物胶束的制备方法是将胶束的疏水性核心通过二硫或多肽交联，这些二硫或多肽可被凝血酶或基质金属蛋白酶2 （MMP2）降解，这些酶在肿瘤部位丰富。适应性聚合物胶束的血液稳定性和肿瘤靶向特性将通过相干抗斯托克斯拉曼散射（CARS）、荧光反射成像（FRI）和荧光分子断层扫描（FMT）进行检测。体外和体内实验的结果将用于改善适应性聚合物胶束的性能，这样的反馈循环将反复进行，以产生最佳的聚合物胶束。我们提出的研究的意义在于，它将阐明影响聚合物胶束在血液中的稳定性，以及细胞摄取和胶束在体内的命运/行为的因素。该项目的成功完成有望产生适应性强的聚合物胶束，有效地将两种药物对靶向递送到肿瘤部位。

DESCRIPTION (provided by applicant): Polymer micelles have been used widely for delivery of poorly water-soluble drugs. Despite their promising properties, they have not been fully developed as a vehicle for target delivery of anticancer agents. This is mainly due to the lack of understanding on the in vivo behavior of polymer micelles upon intravenous administration. Physically self-assembled polymer micelles are not expected to be stable in blood, and yet, no systematic studies have been made. This study is focused on understanding the interactions between polymer micelles and blood components for development of a new class of polymer micelles for targeted delivery of anticancer agents for clinical applications. The long-term goal of this research is to develop adaptable polymer micelles that are stable in blood but undergo dissociation by enzymes abundant at the tumor site. The hypothesis in this project is that the stability of polymer micelles in blood is prerequisite for successful tumor therapy. Only the stable polymer micelles have chances to target tumors and deliver anti-tumoral drugs at the therapeutically effective level. Specific Aims of this project are: (1) to develop adaptable polymer micelles; (2) to examine the micelle stability in blood; (3) to elucidate the micelle-cell interactions; and (4) to characterize the in vivo fate of micelles and to study the anti-tumoral activity of drug-loaded micelles. The two drugs to be used for tumor therapy are paclitaxel and gefitinib, which have similar hydrophobicity. The synergistic effect of the two-drug pair is expected, resulting in substantially better anti-tumoral effect. The adaptable polymer micelles will be prepared by crosslinking the hydrophobic core of the micelles through disulfide or peptides that are degradable by thrombin or matrix metalloproteinase 2 (MMP2) which are abundant at the tumor sites. The blood stability and tumor targeting properties of the adaptable polymer micelles will be examined by coherent anti-Stokes Raman scattering (CARS), fluorescence reflectance imaging (FRI), and fluorescence molecular tomography (FMT). The results of in vitro and in vivo experiments will be used to improve the properties of the adaptable polymer micelles, and such feedback cycle will be repeated to produce the optimal polymer micelles. The significance of our proposed research is that it will elucidate the factors affecting the stability of polymer micelles in blood, as well as cellular uptake, and in vivo fate/behavior of the micelles. Successful completion of this project is expected to produce adaptable polymer micelles that are effective for targeted delivery of a two-drug pair to the tumor sites. PUBLIC HEALTH RELEVANCE: The goal of this project is to develop a new type of polymer micelles that are stable in blood but undergo structural changes by enzymes abundant at the tumor site (i.e., adaptable polymer micelles) for targeted delivery of anticancer agents to the tumor site via intravenous injection.