Albumin-binding nanocomplexes for delivery of combination siRNA therapeutics to KRAS-driven cholangiocarcinoma

研究综述 诊断为晚期胆管癌（CCA）的患者总体预后较差， 有限的治疗选择。小干扰RNA（siRNA）治疗提供了一个有吸引力的沉默策略 缺乏FDA批准的分子靶向治疗的CCA致癌驱动因素，特别是KRAS， 在约22%的肝内和约42%的肝外CCA中发生突变。组合siRNA治疗剂可以是 旨在抢占在靶向治疗过程中经常出现的代偿性耐药途径。 此外，siRNA可以靶向恶性肿瘤的位点，避免由于分子上的不良反应。 在健康器官中的靶向活性，如在许多小分子药物中所见。然而，交付方面的挑战 包括核酸酶降解、快速清除和缺乏细胞摄取或内体的机制 逃逸传统上限制了siRNA的临床应用。我们的团队最近开发了一种技术， 用孪生脂肪酸（siRNA-L2）化学修饰siRNA，所述孪生脂肪酸与 内源性白蛋白（alb-NC）。由于白蛋白通常在血管系统中长循环，但在血管系统中活跃， 我们发现，alb-NC延长siRNA循环时间，促进同质肿瘤， 渗透，并增加肿瘤选择性siRNA摄取。这种技术非常适合纤维化肿瘤， CCA，其主动摄取机制对于递送大型生物治疗剂是必要的。然而，在这方面， siRNA-L2设计还没有与“板载”功能整合以从内体逃逸， 代表siRNA活性的关键屏障。在这个项目中，我建议优化和定制siRNA-L2 alb-NC 这是一个能够有效地肿瘤选择性敲低CCA中致癌驱动因子的平台。 本文提出的研究将检验以下假设： 靶向KRAS和互补耐药途径的siRNA将在KRAS中提供治疗益处。 胆管癌首先，我将化学优化白蛋白-NC，以实现有效的内体逃逸， 细胞内siRNA递送。其次，我将证明KRAS的基因靶向结合合理的- 参与mTOR信号传导或KRAS相关凋亡途径的选定互补基因靶点 治疗阻力然后，我将使用alb-NC进行临床前治疗研究，以提供基于KRAS的 siRNA组合与KRAS突变型肝内CCA的原位小鼠模型。该项目将 通过开发有效的siRNA来解决CCA中对新靶向治疗方法的迫切需求 针对KRAS驱动疾病中关键基因组合的递送技术。

Research Summary Patients diagnosed with advanced cholangiocarcinoma (CCA) have poor overall outcomes and face limited treatment options. Small interfering RNA (siRNA) therapeutics offer an attractive strategy for silencing oncogenic drivers of CCA that lack FDA-approved molecularly-targeted therapeutics, particularly KRAS, which is mutated in ~22% of intrahepatic and ~42% of extrahepatic CCAs. Combination siRNA therapeutics may be devised to preempt compensatory resistance pathways that frequently arise in the course of targeted therapy. Furthermore, siRNA may be targeted to sites of malignancy, avoiding adverse effects due to molecularly on- target activity in healthy organs, as is seen with many small molecule drugs. However, delivery challenges including nuclease degradation, rapid clearance, and lack of a mechanism for cellular uptake or endosome escape have traditionally limited clinical use of siRNA. Our group has recently developed technology to chemically modify siRNAs with twin fatty acids (siRNA-L2) that form non-covalent nanocomplexes with endogenous albumin (alb-NCs). Since albumin is ordinarily long-circulating in the vasculature but is actively taken up by tumors, we have found that alb-NCs extend siRNA circulation time, promote homogeneous tumor penetration, and increase tumor-selective siRNA uptake. Such a technology is well-suited for fibrotic tumors like CCA, for which an active uptake mechanism is necessary for delivery of large biologic therapeutics. However, the siRNA-L2 design has not yet been integrated with “on-board” functionality to escape from endosomes, which represent a critical barrier to siRNA activity. In this project, I propose to optimize and tailor the siRNA-L2 alb-NC platform to enable efficient tumor-selective knockdown of oncogenic drivers in CCA. The studies proposed here will test the hypothesis that alb-NC-mediated delivery of a combination of siRNAs targeting both KRAS and complementary resistance pathways will provide therapeutic benefit in KRAS- driven cholangiocarcinoma. First, I will chemically optimize alb-NCs for efficient endosomal escape and intracellular siRNA delivery. Second, I will credential gene targeting of KRAS in combination with rationally- selected complementary gene targets involved in mTOR signaling or apoptotic pathways implicated in KRAS treatment resistance. I will then perform pre-clinical therapeutic studies using alb-NCs to deliver KRAS-based siRNA combinations to orthotopic mouse models of KRAS-mutant intrahepatic CCA. This project will thus address a pressing need for new targeted therapeutic approaches in CCA by developing efficacious siRNA delivery technologies to target key gene combinations in KRAS-driven disease.