Novel pRNA Nanoparticle Delivery as Directed Therapy for Colorectal Cancer Metastasis

 描述(由申请人提供)：虽然早期结直肠癌(CRC)患者的存活率已经取得了进展，但全身转移(IV期疾病)患者的改善很小。目前的化疗药物虽然在杀死结直肠癌细胞方面非常有效，但受到其全身毒性的限制。如果要在癌症患者的生存方面取得进展，就需要高度创新的策略，直接向转移的结直肠癌提供更有针对性的抗癌药物。我们的最终翻译目标是开发一种高效且毒性较低的方法，专门为转移的结直肠癌提供抗癌药物。为了实现这一目标，我们组建了一个多学科、高度协作的团队，他们在结直肠癌、结直肠癌治疗方式、药物化学、新型纳米颗粒合成和递送系统的分子信号通路方面处于前沿。在过去的两年里，我们在实现我们的目标方面取得了重大进展：(I)利用新的三向连接(3WJ)基序，我们构建了热力学和化学上稳定的三分支RNA纳米颗粒，其适体针对受体，可以将小分子抑制物或化疗药物特异性地输送到肝脏转移瘤中；(Ii)我们以PRNA-3WJ基序为支架构建了各种RNA纳米颗粒，并在关键实验中证明，得到的RNA结构保留了其折叠和独立的功能，用于特定的细胞结合、细胞进入和癌症靶向， 在体外和体内，(Iii)我们已经证明，在系统注射到小鼠体内后，RNA纳米颗粒保持完整，并与肿瘤紧密结合，在正常器官或组织中几乎没有蓄积；这些RNA构建物无毒、无免疫原性，在小鼠身上表现出良好的药理学特征，以及(Iv)我们已经证明了PRNA-3WJ在体内局部递送到结直肠癌移植瘤和肝转移瘤中。因此，我们建议的中心假设是，使用我们的PRNA-3WJ纳米颗粒的CRC受体特异性化疗药物将提供一种安全、有效的策略来选择性地靶向和抑制CRC转移。为了解决我们的假设，我们设计了以下特定目的的实验：1)构建与抗癌药物偶联的PRNA-3WJ纳米粒，并分析其体外稳定性、细胞摄取和抗增殖作用；2)测定PRNA-药物偶联物在体内的药代动力学、稳定性、安全性和药物释放；以及3)评价PRNA-3WJ纳米粒与抗癌药物偶联的选择性给药和体内抗肿瘤作用。综上所述，我们对我们目前的建议的热情不仅是因为它固有的科学重要性，也是因为它的翻译潜力、临床影响以及提供一种更有效、毒性更低的针对结直肠癌转移的递送系统的可能性。

 DESCRIPTION (provided by applicant): Although progress has been made in survival of patients with earlier stage colorectal cancer (CRC), only minimal improvement has been noted in patients with systemic metastases (Stage IV disease). Current chemotherapeutic agents, while highly effective at killing CRC cells, are limited by their systemic toxicity. If advances ar to be made in the survival of cancer patients, highly innovative strategies are required for more targeted delivery of anti-cancer agents directly to CRC metastases. Our ultimate translational goal is to develop a highly effective and less toxic approach to specifically deliver anti-cancer agents to CRC metastases. To achieve this goal, we have assembled a multidisciplinary and highly collaborative team who are at the forefront of molecular signaling pathways in CRC, CRC treatment modalities, medicinal chemistry, novel nanoparticle synthesis and delivery systems. Over the last two years, we have made significant progress to achieve our goals: (i) using a novel three-way junction (3WJ) motif, we have constructed thermodynamically and chemically stable three-branched RNA nanoparticles with an aptamer against receptors that can deliver a small molecule inhibitor or chemotherapeutic agent specifically to CRC metastases in the liver, (ii) we have constructed a variety of RNA nanoparticles using the pRNA-3WJ motif as a scaffold and have demonstrated in critical experiments that the resulting RNA constructs retained their folding and independent functionalities for specific cell binding, cell entry and cancer targeting, both in vitro and in vivo, (iii) we have shown that the RNA nanoparticles remain intact after systemic injection into mice and strongly bind to tumors with little accumulation in normal organs or tissues; these RNA constructs are non- toxic, non-immunogenic, and display favorable pharmacological profiles in mice, and (iv) we have demonstrated localized in vivo delivery of pRNA-3WJ to CRC xenografts and liver metastases. Thus, the central hypothesis of our proposal is that CRC receptor-specific delivery of chemotherapeutic agents using our pRNA-3WJ nanoparticles will provide a safe, effective strategy to selectively target and inhibit CRC metastasis. To address our hypothesis, we have designed experiments with the following Specific Aims: 1) to construct pRNA-3WJ nanoparticles coupled with anti-cancer agents and analyze their stability, cellular uptake and anti-proliferative effects in vitro; 2) to determine te pharmacokinetics, stability, safety and drug delivery of pRNA-drug conjugates in vivo; and 3) to evaluate the selective delivery and in vivo anti-tumor effect of pRNA- 3WJ nanoparticles coupled with anti-cancer agents. In summary, our enthusiasm for our current proposal is driven not only by its inherent scientific importance, but also by its translational potential, clinical impact, and the possibility to provide a more effective and less toxic delivery system targeting CRC metastases.