Targeted delivery of microRNA-loaded microvesicle for cancer therapy

描述（由申请人提供）：一种新的治疗方式是使用寡核苷酸将肿瘤抑制性miRNA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开发的主要瓶颈。微囊泡是内吞来源的膜囊泡的小的同质亚型，并且天然地含有多种细胞生化物质，包括miRNA。该提案将开发一种微泡药物递送系统，将治疗性miRNA靶向肝细胞癌细胞和肿瘤。该系统的独特特征是核酸货物由产生微泡的细胞合成，从而减轻了对合成寡核苷酸的需求。微囊泡将被改造成表达一种靶向肽，将其引导到癌细胞。经工程改造以包括TAR RNA发夹的环区的经修饰的pre-miR-199 a将被插入靶向蛋白基因的内含子中，并且一旦被剪接和加工，将通过结合靶向蛋白上的C末端HIV达特肽而被引导至微囊泡。该项目将使用计算机和生物化学方法， 确定用于肽结合、正确加工和生物活性的最佳pre-miRNA序列。将在体外和原位肝细胞癌模型中评价微泡递送系统的治疗活性和靶向能力。药效学和药代动力学评价将提供关于剂量、毒性、疗效、给药途径和生物分布的详细信息。本文提出了一种高度创新的方法来合成治疗性核酸并将其递送至癌细胞。该系统不依赖于使用合成的寡核苷酸或人工药物递送系统。该技术的未来表现可应用于递送其他核酸药物，如shRNA，并可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.