Reductase Enzyme-responsive, Self-immolative Nanovehicles

描述（由申请人提供）：本申请的目的是评价由氧化还原响应性磷脂制成的囊泡（脂质体）的内容物在脂质体与高度浓缩于大多数癌症肿瘤组织中的特定醌还原酶（即NAD（P）H：醌氧化还原酶1型（NQO 1，DT-心肌黄酶））相互作用后可有效释放的假设。这一点的证明将允许未来开发一组前所未有的氧化还原敏感性脂质体，其结构优化为优先在肿瘤中积累并以位点特异性方式递送其内容物，这是由于它们响应于癌症肿瘤中过表达的还原酶活性而被打开。醌还原酶响应性脂质体的高度特异性去稳定化被提出通过组成脂质体的脂质的稳定醌亚基的选择性酶催化还原而发生。醌基团的还原导致脂质体双层中醌和磷脂之间的共价键断裂，产生不能维持双层的磷脂酰乙醇胺脂质。酶特异性还原导致脂质体的破坏和其内容物的释放。评估该假设的具体目的包括：1）开发具有快速NQO 1催化还原和自裂解速度的合成工程化醌亚基，以便产生高速率的整体NQO 1刺激过程;和2）通过优化NQO 1与醌稳定亚基的相互作用，制备能够快速NQO 1活化破坏的醌-脂质脂质体。这些目标将通过完成一组精心设计的实验目标来实现，这些实验目标解决了具有热力学还原值和自裂解速率的醌脂质的合成，所述醌脂质对于酶促破坏和脂质体（脂质的组成）的配制是最佳的，所述脂质体导致NQO 1与醌亚基的有效相互作用。该项目直接致力于开发一类具有治疗重要疾病（癌症）以及炎症性组织疾病（如类风湿性关节炎）潜力的技术，这些疾病与过度表达的还原酶有关。在这项工作中开发的方法和材料直接适用于机构研究所的任务，包括国家生物医学成像和生物工程研究所，国家癌症研究所和国家眼科研究所的任务。 公共卫生相关性：这项研究的目标是开发一种响应性纳米系统，该系统能够容纳药物，然后在与癌症肿瘤相关的特定蛋白质的存在下刺激药物。与目前市售的纳米级递送系统相比，该响应系统具有提供癌症肿瘤的显著更有效的化学治疗的潜力，且副作用更少。蛋白质响应递送系统的长期影响是巨大的，因为每年约有600万人死于癌症。

DESCRIPTION (provided by applicant): The goal of this application is to evaluate the hypothesis that the contents of vesicles (liposomes) made of redox-responsive phospholipids can be efficiently released upon liposome interaction with a specific quinone reductase enzyme that is highly concentrated in the majority of cancer tumor tissues, namely, NAD(P)H:quinone oxidoreductase type 1 (NQO1, DT-diaphorase). Demonstration of this will allow for the future development of an unprecedented group of redox-sensitive liposomes that are structurally optimized to preferentially accumulate in tumors and deliver their contents in a site-specific manner, as the result of their being opened in response to the overexpressed reductase activities in cancer tumors. Highly specific destabilization of the quinone reductase-responsive liposomes is proposed to occur by selective, enzyme-catalyzed reduction of stabilizing quinone subunits of lipids composing the liposomes. Reduction of the quinone groups leads to cleavage of the covalent link between the quinone and the phospholipid in the liposome bilayer, yielding phosphatidylethanolamine lipids that are unable to sustain bilayers. Enzyme-specific reduction leads to destruction of the liposome and release of its contents. Specific Aims to evaluate the hypothesis include that of: 1) developing synthetically engineered quinone subunits having fast speeds of NQO1-catalyzed reduction and self-cleavage so as to yield a high rate for the overall NQO1-stimulated process; and 2) making quinone-lipid liposomes capable of rapid NQO1-activated destruction by optimizing the interaction of NQO1 with the quinone stabilizing subunits. These Aims will be achieved by completion of a set of carefully designed experimental Objectives that address the synthesis of quinone-lipids having thermodynamic reduction values and self-cleavage rates that are optimal for enzymatic destruction and the formulation of liposomes (composition of lipids) that leads to efficient NQO1 interaction with quinone subunits. This project directly addresses the development of a class of technologies with the potential to treat an important disease, cancer, as well as inflammatory tissue diseases, such as rheumatoid arthritis, that have associated with them overexpressed reductase enzymes. The methods and materials to be developed during this work are directly applicable to the missions of the Agency Institutes, including those of the National Institute of Biomedical Imaging and Bioengineering, the National Cancer Institute, and the National Eye Institute. PUBLIC HEALTH RELEVANCE: This research targets the development of a responsive nanoscopic system capable of containing drugs and then delivering them upon stimulation by the presence of a specific protein associated with cancer tumors. The responsive system has the potential to provide significantly more efficient chemotherapeutic treatment of cancer tumors with fewer side effects in comparison to the current, commercially available nanoscopic delivery systems. The long-term impact of the protein-responsive delivery system is great, for roughly 6 million deaths are attributed to cancer each year.