Targeted delivery of microRNA-loaded microvesicle for cancer therapy

描述(申请人提供)：一种新的治疗方式是使用寡核苷酸将肿瘤抑制miRNAs的水平恢复到正常细胞或组织的水平。治疗性寡核苷酸的成功靶向和递送一直是其临床发展的主要瓶颈。微泡是一种小的同质亚型的膜小泡起源于内吞，并自然含有各种细胞生物化学物质，包括miRNA。这项提议将开发一种微囊药物输送系统，以靶向针对肝癌细胞和肿瘤的治疗性miRNAs。这个系统的一个独特特点是，核酸货物是由产生微泡的细胞合成的，因此减少了对合成寡核苷酸的需求。将对微囊进行改造，以表达一种靶向多肽，将其导向癌细胞。修饰的Pre-miR-199a经改造包括TAR RNA发夹的环区，将被插入靶蛋白基因的内含子，一旦拼接和加工，将通过与靶蛋白上的C末端HIV Tat肽结合而定向到微泡。该项目将在硅胶和生物化学方法中使用 确定多肽结合、正确加工和生物活性的最佳前-miRNA序列。微囊递送系统的治疗活性和靶向能力将在体外和肝细胞癌的原位模型中进行评估。药效学和药代动力学评估将提供有关剂量、毒性、疗效、给药途径和生物分布的详细知识。这里提出了一种高度创新的方法来合成治疗性核酸并将其输送到癌细胞。该系统不依赖于合成寡核苷酸或人工药物输送系统的使用。这项技术的未来表现形式可以应用于输送其他核酸药物，如shRNA，并可能广泛应用于治疗许多疾病。

DESCRIPTION (provided by applicant): A new therapeutic modality is to use oligonucleotides to restore the levels of tumor suppressive miRNAs to that of normal cells or tissues. Successful targeting and delivery of therapeutic oligonucleotides has been a major bottleneck in their clinical development. Microvesicles are a small homogenous subtype of membrane vesicles of endocytic origin and naturally contain a variety of cellular biochemicals including miRNA. This proposal will develop an microvesicle drug delivery system to target therapeutic miRNAs to hepatocellular carcinoma cells and tumors. A unique feature of this system is that the nucleic acid cargo is synthesized by the cells that produce the microvesicles, thus alleviating the need for synthetic oligonucleotides. Microvesicles will be engineered to express a targeting peptide that will direct it to cancer cells. The modified pre-miR-199a, engineered to include the loop region of the TAR RNA hairpin, will be inserted into an intron of the targeting protein gene and once spliced and processed, will be directed to the microvesicle by binding to C-terminus HIV Tat peptide on the targeting protein. This project will use in silico and biochemical approaches to determine the optimal pre-miRNA sequences for peptide binding, correct processing and biological activity. The therapeutic activity and targeting ability of the microvesicle delivery system will be evaluated in vitro and in an orthotopic model of hepatocellular carcinoma. Pharmacodynamic and pharmacokinetic evaluations will provide detailed knowledge on dose, toxicity, efficacy, route of administration and biodistribution. Proposed here is a highly innovatie approach to synthesize and deliver therapeutic nucleic acids to cancer cells. This system does not rely upon the use of synthetic oligonucleotides or artificial drug delivery systems. Future manifestations of this technology can be applied to deliver other nucleic acid drugs such as shRNA and may be widely applicable to treat many diseases.