Application of Gold Nanoparticles to Increase the Efficacy of Radiation Therapy

应用金纳米粒子提高放射治疗的疗效

• 批准号: 8349402
• 负责人: Jacek Capala
• 金额: $ 14.4万
• 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/8349402
• 关键词: Adverse effects; American; Antibodies; Antineoplastic Agents; Apoptotic; Biodistribution; Biological; Biological Models; Cancer Remission; Cell Death; Cells; Characteristics; Chemicals; Chemistry; Cleaved cell; Clinical; Clinical Trials; Colloids; DNA; Development; Dose; Drug Delivery Systems; Drug Formulations; Drug Kinetics; ERBB2 gene; Electrons; Elements; Enhancers; Environment; Fluorescence; Gamma Rays; Gold; Gold Colloid; Heterogeneity; Human; Idoxuridine; In Vitro; Iodine; Length; Location; Malignant Neoplasms; Mediating; Methodology; Methods; Monitor; Multi-Drug Resistance; Mus; Neutrons; Nuclear; Organ; Organelles; Pathway interactions; Pharmaceutical Preparations; Photochemotherapy; Photons; Polymers; Production; Property; Proteins; Publishing; Radiation; Radiation therapy; Radiation-Sensitizing Agents; Radio; Reaction; Reactive Oxygen Species; Research; Roentgen Rays; Site; Societies; Solid Neoplasm; Stress; Sulfhydryl Compounds; Surface; System; Testing; Therapeutic; Therapeutic Agents; Tissues; Toxic effect; Treatment Efficacy; Tumor Tissue; Water; Work; base; biomaterial compatibility; cancer cell; cancer radiation therapy; cancer therapy; chemotherapeutic agent; chemotherapy; clinical application; cytotoxicity; dehalogenation; design; dosage; ds-DNA; efficacy testing; improved; in vitro Model; in vivo; in vivo Model; ionization; irradiation; meetings; monomer; mouse model; nano; nanocarrier; nanoparticle; neoplastic cell; particle; plasmid DNA; polymerization; posters; prevent; receptor; response; single photon emission computed tomography; small molecule; targeted delivery; trafficking; tumor

Background and Significance Over the last two decades, radiation dose enhancement by high atomic number elements such as iodine has been explored for cancer radiotherapy. As a small-molecule radiation dose enhancer (smRDE), iododeoxyuridine (IUdR) has been used due to its facile incorporation into cellular DNA. The subsequent external irradiation of high energy photons on the IUdR-containing target cells can trigger the secondary emission of photoelectric radiation (i.e. Auger/secondary electron emission or X-ray fluorescence). The resulting triggered emission from smRDE can cleave the nuclear DNA double strands that can induce the radio-sensitized cell death. In this smRDE-mediated radiotherapy, several advantages have been demonstrated. The triggered emission from smRDEs generally decays in several um which is a typical length scale of a cell so that the resulting cytotoxicity is highly dependent on the cellular location of smRDEs. Therefore, only those of smRDEs located inside the target cells can deliver high toxicity upon radiation but their off-target toxicity can be reduced out of the cells. Although such smRDEs can improve the radiotherapeutic efficacy with reduced side effects, safe and effective delivery of smRDE to target tissue remains one of the major drawbacks to clinical applications. As iodine-attached tumor-targeting antibodies were used to improve their biodistribution, their targeting and therapeutic efficacies were not satisfied due to the rapid dehalogenation mechanism in DNA as well as the heterogeneity and limited expression of target receptors on cancer cells. Furthermore, the prolonged treatments with high dosages of iodine compounds should be avoided due to their toxic side effects to the host organs. To overcome these limitations, we propose the development of a nano-encased RDE (nano-RDE) platform, based on functionalizable polymer-modified nanoparticles. NanoRDE platforms can demonstrate several advantages: First, the biodistribution of nanoRDE can be highly improved by the enhanced permeation and retention (EPR) effect in solid tumor tissue, that allows for the selective accumulation of nanoRDE at diseased sites (passive targeting). Second, high amount of nanoRDE can be readily internalized in target cells by endocytic pathway which is known as a completely different cellular internalization mechanism from that of small molecules. In addition, the subsequent acidic endosomal environments can be used as a trigger for the pH-sensitive release of additional chemotherapeutic agents. In conventional chemotherapy, the rapid developments of multidrug-resistant characteristics in cancer cells cause a critical problem in clinical cancer treatments. As such, it is obvious that a combinational therapy is highly favorable for the complete remission of cancers rather than a single-type treatment. To this end, anti-cancer drug-conjugated nanoRDE as a first example of multimodal delivery platform for both radio- and chemotherapy will be demonstrated in this project. Gold nanoparticles have been tested for improvement of both chemotherapy and radiotherapy . The TNFalpa-PEG-colloidal gold nanoparticle, CYT-6091 (Citimmune, Gaithersburg, MD), has been shown to selectively traffic to tumor tissue. This agent has been evaluated for its ability to selectively deliver TNFalpha to tumors in clinical trials. Gold nanoparticles are available in a broad range of sizes. In addition to its properties as a nano-carrier, colloidal gold, being a high-Z element, may also increase the radiation dose delivered specifically to the target cells. In this system, gold nanoparticles (AuNPs) are used as inorganic nanoRDEs for radiotherapy as well as a delivery platform for chemotherapeutic agents. Due to the K-edge of gold at 80.7 keV, X-ray radiation with the energy level of Au K-edge can trigger the secondary emission of photoelectric radiation from AuNPs. The resulting radiation can induce the degradation of target molecules by ionization and can interact with surrounding water molecules to produce reactive oxygen species that can damage the target molecules. As such, AuNP-sensitized degradations of plasmid DNA and human proteins upon X-ray radiation have been demonstrated in in vitro model systems. Additionally, when AuNP-containing tumor cells were irradiated, increased apoptotic cell death was detected due to the continuous stress on cytosolic organelles. Furthermore, enhanced in vivo efficacy of AuNPs upon radiotherapy was also observed in human cancer-bearing mouse models. However, these AuNPs have shown very poor pharmacokinetic results due in part to their limited surface functionality as a bare colloidal particle. Recently, AuNPs have been used in a wide range of biological applications due to their biocompatibility and well-known surface chemistry. Using the known reactions, AuNPs can be readily modified with thiol-end-capped polymers that can significantly alter the pharmacokinetics. This functional polymer can be prepared by highly controllable reversible addition-fragmentation chain-transfer (RAFT) radical polymerization which allows for copolymerization of a wide range of monomers. As the gold K-edge is at 80.7 keV and the enhancement is optimal in the photoelectric-dominated X-ray spectrum, irradiation conditions could be optimized by using monoenergetic X-rays. Finaly, gold can be easily activated with thermal neutrons to emit 411 keV gamma rays, which could provide a means for monitoring their biodistribution by SPECT. Hypothesis: Functionalized gold nanoparticles can be used for HER2-targeted delivery and triggered release of therapeutic agents, including radiosensitizers Research Aims 1. Development of HER2-targeted AuNP a) Characterization of biodistribution and pharmacokinetics of Au-NP b) Assessment of biodistribution of neutron-activated Au-NP in vivo by SPECT c) Testing the effect of combining AuNP with external irradiation in vitro and in vivo 2. Application of HER2-targeted AuNP for tumor-specific delivery of therapeutic agents a) Optimization of conditions required for triggered release of the molecules carried by Au NP b) In vitro and in vivo testing of the efficacy of Au-NP-delivered drugs as compared with current formulations. Accomplishments: 1. Methods for quantification of gold concentration in the tissue using neutron activation have been developed and presented on 2009 Annual Meetings of the American Nuclear Society and American Chemical Society 2. Methods for production of pegylated nanoparticles have been established and tested 3. X-ray-triggered release of fluorescent molecules from gold nanoparticles was tested and a poster presentation of the preliminary results received Best American Chemical Society (ACS) poster at the ACS Division of Colloid and Surface on the 2009 Annual Meetings of ACS. 4. Our theoretical work describing the requirements of nanoparticles to be used as photodynamic therapy-based radiosensitizers indicating that gold nanoparticles present an advantageous alternative to nano-scintillatots proposed by others has been published in Radiation Research.

背景和意义 在过去的二十年中，人们已经探索了通过高原子序数元素（例如碘）增强辐射剂量用于癌症放射治疗。作为一种小分子辐射剂量增强剂 (smRDE)，碘脱氧尿苷 (IUdR) 由于其易于掺入细胞 DNA 而被使用。随后高能光子对含有IUdR的靶细胞的外部照射可以触发光电辐射的二次发射（即俄歇/二次电子发射或X射线荧光）。 smRDE 产生的触发发射可以切割核 DNA 双链，从而诱导放射致敏细胞死亡。在这种 smRDE 介导的放射治疗中，已经证明了几个优点。 smRDE 的触发发射通常会在几个微米内衰减，这是细胞的典型长度尺度，因此产生的细胞毒性高度依赖于 smRDE 的细胞位置。因此，只有那些位于靶细胞内部的 smRDE 才能在辐射时产生高毒性，但它们的脱靶毒性可以在细胞外降低。 尽管此类 smRDE 可以提高放射治疗效果并减少副作用，但将 smRDE 安全有效地递送至靶组织仍然是临床应用的主要缺点之一。由于碘附着的肿瘤靶向抗体被用来改善其生物分布，但由于DNA中的快速脱卤机制以及癌细胞上靶受体的异质性和有限表达，其靶向和治疗效果并不令人满意。此外，应避免长期使用高剂量的碘化合物，因为它们对宿主器官有毒副作用。 为了克服这些限制，我们建议开发基于功能化聚合物改性纳米颗粒的纳米封装 RDE (nano-RDE) 平台。 NanoRDE平台可以展示出几个优点：首先，通过实体瘤组织中的增强渗透和保留（EPR）效应可以极大地改善nanoRDE的生物分布，从而允许nanoRDE在患病部位选择性积累（被动靶向）。其次，大量的nanoRDE可以很容易地通过内吞途径内化到靶细胞中，这被称为与小分子完全不同的细胞内化机制。此外，随后的酸性内体环境可用作额外化疗剂的pH敏感释放的触发因素。在传统化疗中，癌细胞的多重耐药特性的快速发展给临床癌症治疗带来了关键问题。因此，很明显，联合治疗比单一治疗更有利于癌症的完全缓解。为此，该项目将展示抗癌药物结合的 nanoRDE 作为放射和化疗多模式递送平台的第一个例子。金纳米颗粒已被测试可改善化疗和放疗。 TNFalpa-PEG-胶体金纳米颗粒 CYT-6091（Citimmune，盖瑟斯堡，马里兰州）已被证明可以选择性地运输到肿瘤组织。该药物已在临床试验中评估其选择性地将 TNFα 递送至肿瘤的能力。金纳米粒子有多种尺寸可供选择。 除了作为纳米载体的特性外，胶体金作为一种高 Z 元素，还可以增加专门传递到靶细胞的辐射剂量。在该系统中，金纳米颗粒（AuNP）被用作放射治疗的无机纳米RDE以及化疗药物的递送平台。由于金的K边为80.7 keV，具有Au K边能级的X射线辐射可以触发AuNPs的光电辐射的二次发射。由此产生的辐射可以通过电离引起目标分子的降解，并可以与周围的水分子相互作用，产生可以损坏目标分子的活性氧。因此，AuNP 敏化的质粒 DNA 和人类蛋白质在 X 射线辐射下的降解已在体外模型系统中得到证实。此外，当含 AuNP 的肿瘤细胞受到辐射时，由于细胞质细胞器的持续应激，细胞凋亡增加。此外，在人类荷瘤小鼠模型中也观察到 AuNPs 对放射治疗的体内疗效增强。然而，这些金纳米粒子表现出非常差的药代动力学结果，部分原因是它们作为裸胶体颗粒的表面功能有限。最近，AuNPs 由于其生物相容性和众所周知的表面化学性质而被广泛应用于生物领域。利用已知的反应，AuNP 可以很容易地用硫醇封端的聚合物进行修饰，从而显着改变药代动力学。这种功能性聚合物可以通过高度可控的可逆加成断裂链转移（RAFT）自由基聚合制备，该聚合允许多种单体共聚。 由于金 K 边位于 80.7 keV，并且在光电主导的 X 射线光谱中增强效果最佳，因此可以通过使用单能 X 射线来优化照射条件。最后，金可以很容易地用热中子激活，发射 411 keV 伽马射线，这可以提供一种通过 SPECT 监测其生物分布的方法。假设：功能化金纳米颗粒可用于 HER2 靶向递送并触发治疗药物（包括放射增敏剂）的释放 研究目的 1. HER2 靶向 AuNP 的开发 a) Au-NP 的生物分布和药代动力学表征 b) 通过 SPECT 评估中子激活的 Au-NP 体内的生物分布 c) 测试组合的效果 AuNP 体外和体内体外照射 2. HER2 靶向 AuNP 在肿瘤特异性治疗药物递送中的应用 a) 优化 Au NP 携带的分子触发释放所需的条件 b) 与现有制剂相比，体外和体内测试 Au-NP 递送药物的功效。成就： 1. 已开发出利用中子活化来量化组织中金浓度的方法，并在美国核学会和美国化学学会 2009 年年会上提出 2. 已建立并测试了聚乙二醇化纳米颗粒的生产方法 3. 测试了 X 射线触发从金纳米颗粒中释放荧光分子，并将初步结果的海报展示获得了最佳美国化学学会 (ACS) 奖 2009 年 ACS 年会上 ACS 胶体和表面分部的海报。 4. 我们的理论工作描述了纳米颗粒用作基于光动力疗法的放射增敏剂的要求，表明金纳米颗粒是其他人提出的纳米闪烁体的有利替代品，已发表在《辐射研究》上。