Molecular mechanism of antiangiogenic properties of gold nanoparticle

描述（由申请人提供）：纳米技术是一个新兴的领域，为推进医学科学和疾病治疗带来了无数的机会和可能性。在纳米尺度上，由于量子尺寸效应，材料的物理化学和生物学性质与其相应的本体对应物根本不同。事实上，通过创建纳米级结构，可以在不改变其化学组成的情况下控制材料的基本物理化学性质，例如，金纳米颗粒（AuNP）具有酒红色，而金属金是金黄色，并且这种酒红色可以通过简单地控制AuNP的大小和形状来调节为粉红色、紫色或蓝色。在这个建议中，我们将通过纳米技术的基础研究来解决一个密切相关的生物医学问题。我们最近已经证明，“裸”金纳米颗粒结合肝素结合生长因子，如VPF/VEGF 165，bFGF和PlGF通过其肝素结合域，并抑制其活动。由于这些生长因子本质上是促血管生成的，因此AuNP独特的抗血管生成特性将对各种血管生成依赖性疾病（例如类风湿性关节炎、黄斑变性、糖尿病视网膜病变和癌症）产生重大影响。该提案的长期目标是阐明金纳米颗粒抑制肝素结合促血管生成生长因子（HB-GFs）功能的分子机制。同时测定金纳米粒子的毒性、药代动力学、代谢，并最终测试其作为抗血管生成剂对晚期卵巢肿瘤生长和转移的抑制作用。血管生成在病理性疾病如类风湿性关节炎、黄斑变性和癌症中起着重要作用。在生理条件下，血管生成受到内源性促血管生成因子如VPF/VEGF 165、PLGF等与抗血管生成因子如血小板反应蛋白-1（TSP-1）、生长抑素、内皮抑素等之间的平衡的严格调节。在病理条件下这种平衡的破坏打开了“血管生成开关”。一些抗血管生成剂目前正在临床上使用，但它们中的大多数仅被设计为抑制VPF/VEGF 165介导的过程。此外，最近的报告表明，这些药物的意外和严重的毒性。此外，最近的临床数据表明，靶向单一途径并不是最有效或最有效的治疗模式。在这种情况下，AuNP可能更有效，因为它可以靶向多种途径（通过破坏VPF/VEGF 165、bFGF、PlGF依赖性途径）。此外，当单独的AuNP可以有效地作为抗血管生成剂时，可以克服与如上所述的常规抗血管生成剂相关的不寻常的毒性。因此，本研究提出的目的是：1）详细确定金纳米颗粒的药理学特性，AuNP的生物分布，毒性和血浆蛋白结合特性，以及2）描述AuNP体内抗血管生成特性的分子机制。该提案的意义在于，如果成功，该应用不仅将提供对AuNPs功能机制的详细了解，这是无机抗血管生成纳米颗粒的第一个例子，而且还将开辟利用无机纳米颗粒作为新型治疗剂的新研究领域。当单独的AuNP可以有效地作为抗血管生成剂时，也可以克服如上所述的与常规抗血管生成剂相关的不寻常的毒性。AuNPs不仅抑制VPF/VEGF 165的功能，而且也抑制bFGF的功能。它可能会结合所有的促血管生成肝素结合生长因子存在于腹水和抑制其功能。这种抑制多种肝素结合生长因子功能的方法是一种更好的方法，因为VPF/VEGF 165和bFGF以外的肝素结合生长因子也负责血管生成和腹水的腹膜积聚。即使针对VEGF的治疗最初是有效的，肿瘤也可能在一段时间后逃避抑制，因为它们突变以表达其他血管生成生长因子。此外，最近的临床数据表明，靶向多个血管生成途径而不是单一途径是更有效的治疗模式。在这种情况下，AuNP将更有效，因为它可以靶向多种途径。上皮性卵巢癌（EOC）是西方国家女性生殖道最常见的恶性肿瘤：1- 2%的女性在其一生中的某个时候发生EOC。这种疾病开始于并局限于腹膜腔。目前，美国国家癌症研究所（NCI）正在鼓励对手术后的晚期卵巢癌患者进行双重治疗。这种将抗癌药物输送到静脉并直接进入腹部的联合方法，将晚期卵巢癌妇女的总生存期延长了约一年。我们可以使用类似的策略来治疗晚期卵巢癌患者。我们可以直接将AuNPs作为抗血管生成剂施用到腹部，并通过静脉注射施用用于晚期卵巢癌的常规抗癌药物。这种给药方式不仅可以阻断血管生成，而且由于肿瘤血管系统的正常化，可以使肿瘤细胞对化疗敏感。

DESCRIPTION (provided by applicant): Nanotechnology is a burgeoning field and brings with it a myriad of opportunities and possibilities for advancing medical science and disease treatment. At the nano scale, the physico-chemical, and biological properties of materials differ fundamentally from their corresponding bulk counter part because of the quantum size effect. In fact, by creating nanometer- scale structures, it is possible to control the fundamental physico-chemical properties of a material without changing it's chemical composition, e.g. gold nanoparticles (AuNPs) have wine red color, whereas metallic gold is golden yellow and this wine red color can be tuned to either pink, or violet or blue by simply controlling the size and shape of AuNPs. In this proposal we will address a germane biomedical problem through basic research in nanotechnology. We have recently demonstrated that "bare" AuNPs bind to heparin binding growth factors such as VPF/VEGF165, bFGF and PlGF through their heparin-binding domain and inhibit their activities. Since these growth factors are pro-angiogenic in nature, therefore the unique antiangiogenic property of AuNPs will have significant impact in various angiogenesis-dependent disorders such as rheumatoid arthritis, macular degeneration, diabetic retinopathy, and cancer. The long-term goal of this proposal is to elucidate the molecular mechanisms by which gold nanoparticle inhibits the function of heparin-binding pro-angiogenic growth factors (HB-GFs). Also to determine the toxicity, pharmacokinetics, metabolism of AuNP and finally test its efficacy as anti-angiogenic agent to inhibit tumor growth and metastasis in advanced stage of ovarian tumor. It is well established that angiogenesis plays a central role in pathological disorders such as rheumatoid arthritis, macular degeneration and cancer. Under physiological conditions, angiogenesis is tightly regulated by a balance between endogenous pro-angiogenic factors such as VPF/VEGF165, PLGF, etc, and antiangiogenic factors such as thrombospondin-1 (TSP-1), somatostatin, endostatin, etc. Disruption of this equilibrium under pathological conditions turns on the "angiogenic switch". Some anti-angiogenic agents are being presently used in the clinics, but majority of them have been designed only to inhibit VPF/VEGF165 mediated processes. In addition, recent reports have indicated unexpected and serious toxicities of these agents. Furthermore, recent clinical data suggest that targeting a single pathway is not the most efficient or effective mode of treatment. In this context AuNPs might be more effective since it can target multiple pathways (by disrupting VPF/VEGF165, bFGF, PlGF dependent pathways). Moreover, unusual toxicities associated with conventional anti-angiogenic agents as mentioned above may be overcome when AuNPs alone can be efficacious as an anti-angiogenic agent. Therefore, the aims proposed in this study are designed to 1) Determine, in detail, pharmacological properties of gold nanoparticles, biodistribution, toxicity and plasma protein binding properties of AuNPs, and 2) Delineate the molecular mechanism of anti-angiogenic properties of AuNP in vivo. The significance of this proposal is that, when successful, this application will not only provide detailed insight into the mechanism of function of AuNPs, the first example of an inorganic anti-angiogenic nanoparticle, but also open a new area of research utilizing inorganic nanoparticles as novel therapeutic agents. The unusual toxicities associated with conventional anti-angiogenic agents as discussed above may also be overcome when AuNPs alone could be efficacious as anti-angiogenic agents. AuNPs not only inhibit the function of VPF/VEGF165, but bFGF as well. It is likely that it will bind to all the pro-angiogenic heparin-binding growth factors present in the ascites and inhibit their function. This method of inhibiting the function of multiple heparin-binding growth factors is a better approach, because heparin-binding growth factors other than VPF/VEGF165 and bFGF are also responsible for angiogenesis and peritoneal accumulation of ascites. Even if therapies directed against VEGF are effective initially, tumors may escape from inhibition after a time as they mutate to express other angiogenic growth factors. Furthermore, recent clinical data suggest that targeting multiple angiogenic pathways rather than a single pathway is a more effective mode of treatment. In this context AuNPs will be more effective as it can target multiple pathways. Epithelial ovarian cancer (EOC) is the most common malignancy of the female genital tract in western countries: 1-2 % of all women develop EOC at some time during their lives. This disease starts at and is limited to the peritoneal cavity. Currently, National Cancer Institute (NCI) is encouraging a dual mode of therapy for advanced ovarian cancer patients, after surgery. The combined methods, which deliver anti-cancer drugs into a vein and directly into the abdomen, extend overall survival for women with advanced ovarian cancer by about a year. We can use similar strategies for the treatment of advanced ovarian cancer patients. We can administer AuNPs directly into the abdomen as an anti-angiogenic agent and administer conventional anticancer drugs, used for advanced ovarian cancer, through intravenous injection. This mode of administration will not only block the angiogenesis but also sensitize the tumor cells to chemotherapy due to the normalization of tumor vasculature.