DUAL-AGENT NANOPARTICLES TO OVERCOME DRUG RESISTANCE

描述（由申报人提供）：药物转运体、药物代谢酶、抗凋亡因子或其他细胞蛋白的过度表达导致耐药性的发生。缺乏一种有效和安全的方法来克服耐药性是一个关键问题，因为在这种方法可用之前，不可能开发出有效的治疗耐药肿瘤的方法。长期目标是通过使用能够靶向治疗肿瘤组织的纳米颗粒，使药物对耐药肿瘤有效。这项R21资助申请的目的是获取有关同时使用可生物降解纳米颗粒进行基因沉默和药物递送以克服耐药性的有效性的高级初步数据。两种促进耐药性发展的细胞蛋白（p -糖蛋白和热休克蛋白70）将成为基因沉默的目标。该研究的中心假设是，双药纳米颗粒将维持siRNA和紫杉醇的细胞递送，从而增强紫杉醇的积累和细胞毒性，并最终导致耐药肿瘤的消退。这项研究的基本原理是，一旦获得了证明纳米颗粒疗效的初步数据，随后将对纳米颗粒介导的双重治疗方法进行明确的研究。该研究的具体目的是：(1)制备具有持续细胞毒性的双药纳米颗粒，(2)确定双药纳米颗粒在体内靶向肿瘤的动力学，(3)确定双药纳米颗粒在体内的抗肿瘤功效。目的1在体外研究纳米颗粒释放的siRNA和紫杉醇的剂量对MDR肿瘤细胞毒性的影响。在目标2中，将在小鼠异种移植肿瘤模型中确定静脉注射纳米颗粒制剂后纳米颗粒在肿瘤组织中积累的动力学。在目标3中，将在小鼠耐药肿瘤模型中确定双药纳米颗粒肿瘤消退的剂量依赖性。拟议的研究意义重大，因为它们有望为后续双药纳米颗粒治疗肿瘤耐药疗效的明确研究提供基础。化疗耐药是肿瘤细胞中常见的现象。据估计，每年将有多达50万新发癌症病例最终表现出耐药性表型，这突显了这一问题的重要性。这项拟议的研究预计将对人类健康产生积极影响，因为它有望导致开发出治疗耐药肿瘤的有效方法。

DESCRIPTION (provided by applicant): Overexpression of drug transporters, drug metabolizing enzymes, anti-apoptotic factors or other cellular proteins results in the development of drug resistance. Lack of an effective and safe approach to overcome drug resistance is a critical problem, because, until such an approach is available, it will not be possible to develop effective therapies for drug-resistant tumors. The long-term goal is to enable the effectiveness of drugs against drug-resistant tumors through the use of nanoparticles capable of targeting desired therapies to the tumor tissue. The objective of this R21 grant application is to acquire advanced preliminary data regarding the efficacy of simultaneous gene silencing and drug delivery using biodegradable nanoparticles to overcome drug resistance. Two cellular proteins (P-glycoprotein and Heat shock protein 70) that contribute to the development of drug resistance will be targeted for gene silencing. The central hypothesis of the proposed research is that dual-agent nanoparticles will sustain the cellular delivery of siRNA and paclitaxel, resulting in enhanced paclitaxel accumulation and cytotoxicity, and ultimately, regression of resistant tumor. The rationale for the proposed research is that, once the preliminary data demonstrating the efficacy of nanoparticles is acquired, subsequent definitive investigations on nanoparticle-mediated dual-therapy approach will ensue. The specific aims of the proposed research are to (1) Formulate dual-agent nanoparticles that demonstrate sustained cytotoxicity, (2) Determine kinetics of tumor-targeting with dual-agent nanoparticles in vivo, and (3) Establish the in vivo anti-tumor efficacy of dual-agent nanoparticles. In aim 1, the effect of dose of siRNA and paclitaxel released from nanoparticles on cytotoxicity in MDR tumor cells will be determined in vitro. In aim 2, kinetics of nanoparticle accumulation in tumor tissue following intravenous administration of nanoparticles formulations will be determined in a mouse xenograft tumor model. In aim 3, dose-dependency of tumor regression with dual-agent nanoparticles will be determined in a mouse model of resistant tumor. The proposed studies are significant, because they are expected to provide the foundation for subsequent definitive studies of the therapeutic efficacy of dual-agent nanoparticles against tumor drug resistance. Chemotherapy resistance is a frequent phenomenon in cancer cells. The significance of this problem is highlighted by the estimations that up to 500,000 new cases of cancer each year will eventually exhibit drug-resistant phenotype. The proposed research is expected to positively affect human health, because, it is expected to lead to the development of an effective approach for the treatment of drug resistant tumors.