Development of a gold nanoparticles based targeted delivery system

描述（由申请人提供）：药物的靶向递送应导致增强的治疗功效，副作用低至最小。这是一个被广泛接受的概念，但由于缺乏可用的技术和验证过程，在应用中受到限制。生物医学纳米技术可以在这方面发挥重要作用。生物医学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。它是一个多学科领域，跨越生物学，化学，材料科学，工程和医学学科。在纳米尺度上，材料（金属、半导体等）的物理化学和生物学性质与它们相应的本体对应物（bulk counter part）根本不同，因为量子尺寸效应，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的尺寸和形状而被调谐为粉红色、紫色或蓝色。此外，纳米颗粒还具有大的表面积以负载多种诊断（如光学、放射性同位素、磁性）和治疗（如药物）。在这个应用中，我们希望利用纳米颗粒的独特性质来创建一个靶向递送系统，该系统将显示更好的治疗效果，副作用最小甚至没有副作用。本项目的长期目标是开发一种基于纳米颗粒的递送系统，用于靶向递送细胞毒性药物，提高疗效并降低全身毒性。我们的初步研究表明，使用抗EGFR抗体（C225）作为靶向剂靶向递送低剂量的吉西他滨（Gem）作为金纳米缀合物，导致药物在胰腺癌的原位人异种移植模型中抑制肿瘤生长的功效增强。这些结果鼓励我们深入研究纳米纤维素工艺，以进一步提高疗效，并阐明增强药物活性的机制。因此，我们提出的研究中心的金纳米粒子（金纳米粒子）作为一个交付车辆，宝石作为细胞毒性药物和C225作为靶向剂结合到同一个金核心的“2合1”的方式。首先通过测定纳米缀合物对原发性（PANC-1，MiaPaca 2）和转移性（AsPC-1）人胰腺癌细胞系的活性，在体外测试纳米紫杉醇的功效。因此，研究这些模型的有效性将使我们能够确定这些系统在广泛疾病条件下的应用（例如原发性与转移性疾病，疾病的早期与晚期）。这些细胞的EGFR表达模式也不同，具有较高表达的细胞（PANC-1和AsPC-1）将比MiaPaca 2（具有低EGFR表达）摄取更多的纳米缀合物。然后将在胰腺癌的临床前小鼠模型中测试体内功效。本研究中提出的目的旨在（i）优化用于体外和体内靶向递送的纳米制剂工艺，（ii）确定靶向递送与非靶向递送中纳米缀合物的药代动力学、生物分布和毒性，以及（ii）确定靶向递送与非靶向递送中纳米缀合物抑制肿瘤生长、转移和增加存活的治疗功效。胰腺癌是美国癌症死亡的第四大原因。目前，手术是唯一的选择，然而，由于晚期表现，只有10- 15%的患者适合手术。这项申请的意义在于，它将研究使用纳米递送系统对目前没有有效治疗方法的胰腺癌进行抗癌药物的靶向和非靶向递送。以靶向方式的这种递送将增强药物的功效，同时副作用最小。根据我们的假设，当吉西他滨作为金纳米缀合物以靶向方式递送时，将具有降低的全身毒性和更好的疗效。本申请还将解决许多问题以获得优化的递送载体，例如将靶向剂和药物装载到纳米颗粒、药物的生物利用度、金纳米颗粒和纳米缀合物的生物相容性和毒性。对于那些抗体未能成功靶向所有胰腺肿瘤细胞的患者或不表达EGFR的患者，我们可能会使用其他靶标，如癌胚抗原（CEM）或碳水化合物抗原19-9（CA-19-9），或者需要进一步鉴定其他靶向分子并扩展我们的“概念验证”实验。重要的是，由于我们已经讨论了EGFR在许多其他癌症如CRC、NHSC、NSCLC中过表达，并且吉西他滨也用于其他恶性肿瘤如NSCLC、膀胱癌、乳腺癌，因此，该策略不仅可以用于治疗胰腺癌，而且可以作为治疗许多其他恶性肿瘤如CRC、NHLC、NSCLC、乳腺癌、卵巢癌、卵巢癌、胰腺等

DESCRIPTION (provided by applicant): Targeted delivery of a drug should result in enhanced therapeutic efficacy with low to minimal side effects. This is a widely accepted concept, but limited in application due to lack of available technologies and process of validation. Biomedical nanotechnology can play an important role in this aspect. Biomedical nanotechnology is a burgeoning field and brings with it a myriad of opportunities and possibilities for advancing medical science and disease treatment. It is a multidisciplinary field cutting across the disciplines of biology, chemistry, materials science, engineering and medicine. At the nano scale, the physico-chemical, and biological properties of materials (metals, semiconductors, etc) differ fundamentally from their corresponding bulk counter part because of the quantum size effect 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. Furthermore, nanoparticles also have large surface area to load multiple diagnostic (such as optical, radioisotope, magnetic) and therapeutic (such as drugs). In this application we want to exploit the unique properties of nanoparticles to create a targeted delivery system that will show better therapeutic efficacy with minimal to no side effects. The long-term goal of this project is to develop a nanoparticle-based delivery system for targeted delivery of cytotoxic drug with enhanced efficacy and reduced systemic toxicity. Our preliminary studies demonstrated that targeted delivery of a low dose of gemcitabine (Gem) as a gold nanoconjugate using anti-EGFR antibody (C225) as a targeting agent resulted in enhanced efficacy of the drug to inhibit the tumor growth in an orthotopic human xenograft model of pancreatic cancer. These results encouraged us to study, in depth, the nanofabrication process to improve the efficacy further and delineate the mechanism of enhanced drug activity. Therefore, our proposed studies center on gold nanoparticles (AuNPs) as a delivery vehicle, Gem as a cytotoxic drug and C225 as a targeting agent bound to the same gold core in a "2 in 1" fashion. The efficacy of nanofabrication will be tested in vitro first by determining the activity of the nanoconjugates against primary (PANC-1, MiaPaca2) and metastatic (AsPC-1) human pancreatic cancer cell lines. Therefore, studying efficacy in these models will allow us to determine the application of these systems in a wide range of disease condition (e.g. primary vs. metastatic disease, early stage vs. late stage of the disease). These cells also differ by EGFR expression pattern, cells with higher expression (PANC-1 and AsPC-1) will uptake more of the nanoconjugates than MiaPaca2 (with low EGFR expression). In vivo efficacy will then be tested in a preclinical mouse model of pancreatic cancer. The aims proposed in this study are designed to (i) optimize the nanofabrication process for targeted delivery in vitro and in vivo, (ii) to determine the pharmacokinetics, biodistribution and toxicity of the nanoconjugates in targeted vs. non-targeted delivery and (ii) to determine the therapeutic efficacy of the nanoconjugates to inhibit tumor growth, metastasis and increasing survival in targeted vs. non-targeted delivery. Pancreatic cancer is the 4th leading cause of cancer deaths in United States. Currently, surgery is the only option, however, due to late presentation only 10-15 % of the patients are amenable to surgery. The significance of this application is that it will study both targeted and non-targeted delivery of anti-cancer drugs using a nanodelivery system against pancreatic cancer where no effective therapy is currently available. Such a delivery in targeted fashion will enhance the efficacy of the drug with minimal side effects. According to our hypothesis, gemcitabine will have reduced systemic toxicity with better efficacy when delivered in a targeted fashion as a gold nanoconjugates. This application will also address a number of issues to obtain an optimized delivery vehicle such as loading of targeting agent and drug to a nanoparticle, bioavailability of the drug, biocompatibility and toxicity of gold nanoparticles and nanoconjugates. For those patients where the antibody is unsuccessful in targeting all the pancreatic tumor cells or patients that do not express EGFR, we may use other targets such as carcinoembryonic antigen (CEM) or carbohydrate antigen 19-9 (CA-19-9) or need to further identify other targeting molecules and expand our "proof of concept" experiments. Importantly, as we have already discussed that EGFR is overexpressed in a number of other cancers such as CRC, NHSC, NSCLC and gemcitabine is also used in other malignancies such as NSCLC, bladder, breast, therefore, this strategy could be used not only for the treatment of pancreatic cancers but also as a generalized approach in the treatment of a number of other malignancies such as CRC, NHLC, NSCLC, breast, ovarian, etc.