Therapeutic Targeting of the Ras Pathway By Nanoparticle Delivery of siRNA

项目2：通过纳米粒传递siRNA靶向RAS通路 三种类型的纳米粒子，即LPD，LCP和Print，将被用来在基因工程小鼠(GEM)模型(Kim，co-PI)中将siRNA传递到肺癌细胞。LPD是一种自组装的核/膜纳米粒子，其独特之处在于表面接枝了高密度的聚乙二醇链。Huang(co-Pi)以前的工作表明，LPD在移植的人肺肿瘤中累积在每克组织60%-80%的注射剂量水平，肝脏和脾摄取最少。每日三次静脉注射。注射含有siRNA的LPD可有效沉默肿瘤靶基因的表达。LCP在结构上与LPD相似，但核心被无定形纳米聚磷酸钙取代，该纳米聚磷酸钙溶解在内体酸性pH中释放其货物，并膨胀和破裂内体。印刷品(DeSimone，co-1)是自上而下制造的纳米颗粒，任何载体和货物材料都可以很容易地装载在其中。德西蒙博士已经证明，siRNA可以被成功地装载到印刷品中，并被运送到肿瘤细胞中，以实现基因沉默。该项目的一个显著特点是KRAS驱动的肺癌宝石。针对RAS和RAS效应通路设计的siRNAs将作为治疗药物进行测试和交付。这一点特别重要，因为RAS被传统的药物化学方法认为是一个不可用药的靶点。 此外，吉西他滨的代谢物吉西他滨一(或二)磷酸(GMP或GDP)将被制成LCP纳米颗粒，并单独或与siRNA一起输送到肿瘤细胞。这是一种新的方法，利用了这些纳米颗粒的大载货能力。该项目具有里程碑意义，因为到第三年年底，将确定至少一种纳米颗粒配方，用于GEM的治疗、药代动力学和毒性研究。该配方应准备好与NCI纳米技术表征实验室合作进行详细的表征和毒性研究 进一步的翻译开发

Project 2: Therapeutic Targeting of the Ras Pathway by Nanoparticle Delivery of siRNA Three types of nanoparticles, i.e. LPD, LCP and PRINT, will be used to deliver siRNA to lung cancer cells in a genetically engineered mouse (GEM) model (Kim, co-PI). LPD is a self-assembled, core/membrane nanoparticle, the unique feature of which is the high density ofthe surface grafted PEG chains. Previous work by Huang (co-PI) has shown that LPD accumulates in xenografted human lung tumors at the level of 60-80 % injected dose per g of tissue with minimal uptake by liver and spleen. Three daily i.v. injections of LPD containing siRNA effectively silenced the tumor target gene expression. LCP is similar in structure to LPD, but the core is replaced with calcium phosphate amorphous nanoprecipltate that dissolves in the endosomal acidic pH to release its cargo and swells and bursts the endosomes. The PRINT (DeSimone, co-1) are topdown manufactured nanoparticles In which any carrier and cargo materials can be readily loaded. Dr. DeSimone has shown that siRNA can be successfully loaded in PRINT and delivered to tumor cells for gene silencing. A salient feature of the project is the KRas driven lung cancer GEM. sIRNAs designed against Ras and Ras effector pathways will be tested and delivered as therapeutics. This is particularly significant, because Ras is considered an undruggable target by conventional medicinal chemistry approaches. Furthermore, gemcitabine mono (or di-) phosphate (GMP or GDP), metabolites of gemcitabine will be formulated in LCP nanoparticles and delivered to the tumor cells by itself or together with siRNA. This is a novel approach that takes advantage of the large cargo capacity of these nanoparticles. The project is milestone driven in that by the end of the year 3, at least one nanoparticle formulation will be identified for therapy, pharmacokinetics and toxicity studies In GEM. The formulation should be ready for detailed characterization and toxicity studies in collaboration with Nanotechnology Characterization Lab at NCI for further translational development