RNA Therapeutics for Pancreatic Cancer

胰腺癌的 RNA 治疗

• 批准号: 8045648
• 负责人: Rebekah White
• 金额: $ 15.3万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-17 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8045648
• 关键词: Binding; Cell Surface Receptors; Cells; Complex; DNA; Data; Disease; Distant; Drug Formulations; Epidermal Growth Factor Receptor; Excision; Genetically Engineered Mouse; In Vitro; Learning; Libraries; Malignant neoplasm of pancreas; Mediating; Normal Cell; Nucleic Acids; Operative Surgical Procedures; Patients; Polymers; Process; Proteins; RNA; Radiation; Regional Disease; Relative (related person); Research; Resistance; Screening procedure; Small Interfering RNA; Surface; Technology; Testing; Therapeutic; Therapeutic Effect; Time; TimeLine; Tumor Tissue; Unresectable; Xenograft procedure; advanced disease; aptamer; cancer cell; cellular targeting; chemotherapeutic agent; chemotherapy; combinatorial; cytotoxic; effective therapy; gemcitabine; improved; in vivo; irradiation; mouse model; novel; nuclease; nucleolin; pancreatic cancer cells; prostate stem cell antigen; receptor; response; tumor

DESCRIPTION (provided by applicant): The vast majority of patients with pancreatic cancer are not cured by resection alone. Standard therapies are associated with low response rates and modest improvements in survival, and there is a dire need for more effective therapies. Aptamers are a class of therapeutic nucleic acid (RNA or DNA) molecules, which specifically bind to existing target proteins. Aptamers are generated by an iterative screening process of large combinatorial libraries that can be modified for nuclease resistance. Aptamers can have direct therapeutic effects mediated by binding their protein targets. In addition, aptamers that bind to cell surface receptors can be internalized by cells expressing those receptors and be utilized to deliver other therapeutic cargo. Our global hypothesis is that aptamers that bind targets over-expressed on pancreatic cancer cells relative to normal cells can be used to selectively deliver cytotoxic cargo, such as small interfering RNAs (siRNAs) or chemotherapeutic agents, to pancreatic cancer cells. We have 2 specific aims: Specific Aim #1: To utilize selection strategies against complex targets to identify new pancreatic cancer targets. The ideal target for aptamer-mediated delivery is one that is highly expressed on the surface of all pancreatic cancers, efficiently internalized, and not expressed on the surface of normal cells. Selection strategies utilizing complex targets such as whole cancer cells or tumor tissue in vivo allow the aptamers to choose their own targets. This aim includes in vitro selection against whole pancreatic cancer cells as well as in vivo selection against pancreatic cancer xenografts and genetically engineered mouse models of pancreatic cancer. We will characterize selected aptamers by identifying their specific protein and cellular targets. This aim therefore has the potential to simultaneously identify novel targets and the agents to mediate delivery to them. Aptamers that are internalized by pancreatic cancer cells will be further evaluated in Aim #2. Specific Aim #2: To utilize aptamers that is internalized by pancreatic cancer cells for specific delivery of siRNAs and other therapeutic cargo. We have preliminary data demonstrating that a RNA aptamer that binds EGFR and a DNA aptamer that binds nucleolin are internalized by pancreatic cancer cells. In parallel with the identification of new aptamers in Aim #1, we will utilize these extant aptamers to optimize constructs for delivery of K-ras siRNAs and gemcitabine polymers into cells. Then, we will use aptamers discovered in Aim #1 with the cargo technology gained in the first part of Aim #2 to formulate more specific and effective constructs to deliver K-ras siRNAs and gemcitabine polymers into pancreatic cancer cells in vitro and in vivo. PUBLIC HEALTH RELEVANCE: Standard therapies for pancreatic cancer (surgical resection, chemotherapy, and radiation) are not very effective. The objective of this project is to develop novel agents that target proteins that are present at higher levels on pancreatic cancer cells than on normal cells and that can be used to selectively deliver toxic cargo to pancreatic cancer cells. Such agents would be used in combination with standard therapies to improve survival in patients with advanced disease and cure a larger percentage of patients with respectable disease.

描述（由申请人提供）：绝大多数胰腺癌患者仅靠切除术无法治愈。标准疗法的反应率较低，且生存率改善有限，因此迫切需要更有效的疗法。适体是一类治疗性核酸（RNA 或 DNA）分子，可特异性结合现有的靶蛋白。适配体是通过大型组合文库的迭代筛选过程产生的，可以对其进行修改以实现核酸酶抗性。适体可以通过结合其蛋白质靶标而产生直接的治疗效果。此外，与细胞表面受体结合的适体可以被表达这些受体的细胞内化，并用于递送其他治疗货物。我们的总体假设是，结合在胰腺癌细胞上相对于正常细胞过度表达的靶标的适体可用于选择性地将细胞毒性货物，例如小干扰RNA (siRNA)或化疗药物递送至胰腺癌细胞。我们有 2 个具体目标： 具体目标 #1：利用针对复杂靶点的选择策略来识别新的胰腺癌靶点。适体介导的递送的理想靶标是在所有胰腺癌表面高度表达、有效内化且在正常细胞表面不表达的靶标。利用复杂靶标（例如体内整个癌细胞或肿瘤组织）的选择策略允许适体选择自己的靶标。该目标包括针对整个胰腺癌细胞的体外选择以及针对胰腺癌异种移植物和胰腺癌基因工程小鼠模型的体内选择。我们将通过鉴定其特定的蛋白质和细胞靶标来表征选定的适体。因此，这一目标有可能同时识别新的目标和介导向其传递的药物。被胰腺癌细胞内化的适体将在目标#2 中进一步评估。具体目标#2：利用胰腺癌细胞内化的适体来特异性递送 siRNA 和其他治疗药物。我们有初步数据表明，结合 EGFR 的 RNA 适体和结合核仁素的 DNA 适体被胰腺癌​​细胞内化。在目标 #1 中鉴定新适体的同时，我们将利用这些现有的适体来优化用于将 K-ras siRNA 和吉西他滨聚合物递送到细胞中的构建体。然后，我们将使用目标#1中发现的适体以及目标#2第一部分中获得的货物技术来制定更特异和有效的构建体，以在体外和体内将K-ras siRNA和吉西他滨聚合物递送到胰腺癌细胞中。 公众健康相关性：胰腺癌的标准疗法（手术切除、化疗和放疗）不是很有效。该项目的目标是开发新的药物，其靶向胰腺癌细胞上比正常细胞水平更高的蛋白质，并且可用于选择性地将有毒物质递送至胰腺癌细胞。此类药物将与标准疗法联合使用，以提高晚期疾病患者的生存率，并治愈更大比例的患有严重疾病的患者。