载siRNA的纳米制剂研究进展

目的:为小干扰RNA(siRNA)纳米制剂递送的研究提供参考。方法:以"基因治疗""RNA干扰""小干扰RNA""载体系统""siRNA""Gene therapy""RNA interference""Protamine"等为关键词,组合查询1996-2016年在PubMed、中国知网、万方、维普等数据库中的相关文献,对载siRNA的纳米制剂的导入方法、载体类型及影响递送过程的主要因素进行综述。结果:共检索到相关文献500余篇,其中有效文献40篇。载siRNA的纳米制剂导入方法主要分为物理化学法和载体介导法。在载体介导法中的非病毒载体,不仅克服了siRNA半衰期短、生物利用度低等缺点,而且在一定程度上提高了siRNA的递送效率,是现代药剂学研究的一个热点。常用非病毒载体包括阳离子脂质体、二元复合物纳米载体、三元复合物纳米载体。载体靶向性修饰、粒径与表面电荷是递送siRNA纳米载体主要影响因素。siRNA的高效递送依赖于新的高效、低免疫原性载体的开发以及纳米制剂递送系统的优化。因此,可载siRNA的高效、低免疫原性纳米制剂的研究任重而道远。     

RNAi在肿瘤基因治疗药物研究中的应用

肿瘤是多种基因突变的累积以及这些基因相互作用形成的基因网络调控的结果,目前RNA干扰技术越来越多地拓宽到肿瘤医学的研究领域。本文就RNA干扰技术在肿瘤基因治疗、在候选基因的发现和筛选中的应用以及临床研究进展方面做一综述。     

siRNA的体内递送及药物代谢动力学特性

siRNA作为一种高效的RNA干扰药物在疾病治疗方面前景广阔。但其临床应用还需解决由于高负电荷和分子量等引起的体内递送系统、脱靶效应、免疫激活、毒副作用、改善其药物代谢动力学特性等问题。本文简要综述了siRNA的作用原理、体内递送方式、药代动力学特性、安全问题及临床应用展望。     

siRNA体内递送研究进展

RNA干扰(RNA interference,RNAi),是一种在动植物中存在的通过双链RNA诱导同源特异性序列转录后基因沉默的过程。虽然小干扰RNA (siRNA) 较单链反义寡核苷酸显示出更好的稳定性与基因沉默效果,但是作为新型的基因治疗药物,靶向递送siRNA是药物进入临床应用最主要的环节,siRNA体内有效作用发挥的关键在于它在体内能否高效递送至靶细胞并与靶基因结合。目前研究主要集中在siRNA的修饰方式与递送载体研究,以提高其体内的稳定性与靶向性。文中主要综述了siRNA的体内靶向递送障碍以及近几年siRNA非病毒递送载体脂质体、阳离子多聚物、纳米粒、胶束等方面的研究进展。     

小干扰RNA(siRNA)药物药代动力学特征及生理药代动力学建模现状

小干扰RNA (small interfering RNA, siRNA)是以RNA干扰(RNAi)为基础的一类具有独特药代动力学特性和作用机制的药物,目前已有5种基于两种递送系统的siRNA药物上市获批,并且有越来越多的siRNA药物进入临床研究阶段。生理药代动力学(PBPK)建模是一种辅助药物开发和决策的可靠的工具,并且越来越被监管机构接受, PBPK模型在小分子和大分子领域广泛应用的背景下,在指导siRNA类药物开发方面仍然处于起步阶段。本文结合siRNA类药物的药代动力学特征,概述了siRNA类药物PBPK模型开发的现状及模型构建中所需的关键参数,以期为今后PBPK模型在siRNA类药物研发中的应用,及优化设计临床前试验获得关键数据提供一定的借鉴。     

siRNA药物研究进展

小干扰RNA(small interfering RNA,siRNA)药物作为小核酸药物研发的热点,凭借基因沉默效率高、不良反应可控、合成方便等优点,得到了广泛应用.siRNA裸序列不稳定,在体内递送困难,不易到达靶点发挥作用,成为早期siRNA药物研发的阻力.近年来,siRNA的稳定性修饰以及高效递送系统的开发,大大...     

RNA组合干扰技术及其在肿瘤基因治疗中的应用

RNA干扰(RNAi)为基因治疗提供了一个全新的思路。但单一的RNAi治疗只针对单个基因,因而最终无法治愈多基因变异引起的肿瘤。为了克服RNAi单基因治疗的不足,研究人员提出了RNA组合干扰(combinatorial RNA interference,coRNAi)的治疗策略。coRNAi通过联合应用针对单个或多个靶基因的RNAi诱发物以及其他RNA或蛋白沉默因子实现沉默靶基因、抑制肿瘤生长和促进肿瘤细胞凋亡。本文重点介绍了coRNAi的主要联合方式以及在肿瘤基因治疗中的研究进展。     

siRNA药物的临床研究进展

RNA干扰技术作为一种新型的基因沉默技术,因其具有高效、高特异性、低毒性等优点,应用RNA干扰技术开发新型的靶向药物,已成为当今药物研究领域中重点发展方向之一。siRNA作为药物应用于临床已经取得很大的发展但仍面临许多挑战。本文对RNA干扰机制、临床试验现状及发展前景作简要综述。     

siRNA技术抑制流感病毒的应用最新研究进展

流感的流行长期以来给世界人民的身心健康、生命安全和财产等都带来了严重的威胁和巨大的损失,而流感病毒表面抗原容易变异的特性导致使用疫苗预防流感效果欠佳,目前应用的抗流感药物不良反应较大,易产生抗药性。近年来,RNA干扰技术在抗病毒感染方面显示出广阔的前景。合适的siRNA片段对于抑制流感病毒的复制有巨大的潜能,虽然RNA干扰技术还存在如特异性和组织分布性等关键性问题使之尚未用作临床治疗流感的方法,但其对于抑制呼吸道病毒感染其中包括抑制流感病毒的感染确实具有巨大潜能。     

关于基因治疗药物生物分布研究检测方法的探讨

生物分布研究是考察药物自给药部位进入人体以后到达靶器官的情况,和伴随时间延长的代谢消除趋势,是基因治疗药物特有的实验内容.人体暴露于外源基因片段时易于发生严重危害,需要采用适宜方法考察药物基因进入体内情况以预测其潜在安全风险.当前,多个监管机构均要求在非临床阶段开展此项研究,并且在申报临床试验之前提供相关数据.本文主要...     

RNAi: for functional analysis and target validation

The third annual conference on discovery on target, organised by the Cambridge Healthtech Institute was held on 19 – 20 October 2005, in Boston. More than 300 delegates from both academic and industrial institutes attended the meeting. The presentations provided insights into understanding the RNA interference technology as a useful tool to identify and validate new targets for therapeutic intervention. Discussions focused in the design of siRNA for effective gene silencing, RNAi screens to identify new targets, RNAi delivery and the in vivo validation of targets using this technology.     

RNAi技术应用新进展

RNA干扰(RNAi)是由小分子双链RNA引发的转录后基因沉默现象.作为一种具有革命性的基因转录后调控新技术,正在被广泛应用于功能基因组研究的多种领域.它不仅是基因功能研究的有力工具,而且为特异性基因治疗提供了新的技术手段和应用前景,因而RNAi技术正日益成为后基因组时代基因功能和调控分析的有力工具.     

Complexity in the therapeutic delivery of RNAi medicines: an analytical challenge

Introduction: Nucleic acids have witnessed a dramatic acceleration in their therapeutic exploitation and currently represent a growing number of applications in drug development pipelines. However, a more wide-spread development of therapeutics based on nucleic acids is restricted by their poor chemical and enzymatic stability in vivo, lack of cellular uptake and insufficient capability to reach intracellular targets.

Areas covered: Advanced formulation of nucleic acids in nano-sized carriers may help unlocking their potential as therapeutic agents. Nano-sized matters own specific features responsible for inducing characteristic interactions with biological molecules and tissues. These properties enable for the enhancement of the nano-formulation’s therapeutic efficacy, but on the other hand, the nanomatters interactions in biological fluids are also responsible for adverse effects. The purpose of this review is to reflect on the complexity in the therapeutic delivery of RNA interference-based drugs emerging from the recent clinical experiences and report the actual technological and analytical advances introduced to solve it.

Expert opinion: The complexity in the therapeutic delivery of nucleic acids and the heterogeneity of side effects make the interpretation of the therapeutic outcome difficult. Hence the development of analytical approaches applicable in the field of nucleic acid delivery is becoming a major challenge.     

Patent strategies for therapeutic RNAi

Background: RNAi is an emerging and powerful technology with tremendous potential to treat a diverse number of diseases. There is little doubt about the potential commercial value of this technology; however, to fully exploit this potential, a carefully planned and executed patent strategy must be employed. Objective: Our objectives were to i) explore the requirements for patentability in the United States and apply these requirements to RNAi technology; ii) examine key differences between US and international patent systems that may be relevant to patenting RNAi technology in international venues; and iii) identify the areas of patent coverage that a company will need to acquire if it is to be successful in the RNAi field. Method: In view of the relatively recent emergence of the RNAi field, our analysis relied heavily on lessons learned from more mature technologies, such as monoclonal antibodies, gene therapy, and antisense technology, in order to identify the strengths and weaknesses of an RNAi patent estate. Results/conclusion: A successful RNAi patent position will require access to patents in the following three areas: i) general patents covering relatively broad aspects of RNAi action; ii) patents for platform technologies for exploiting RNAi; and iii) focused patents directed to specific diseases, RNAs and gene targets. While a patent position in one or even two of these areas might put a company into a blocking position, the key to commercial success will be possession of or access to patents in all three areas, as well as a proprietary position in at least one.     

RNA-based therapeutic strategies for cancer

Recent progress in the field of RNA therapeutics has highlighted the potential of using RNA-based strategies for the treatment of human cancer. Emerging technologies such as small interfering RNA (siRNA) to trigger RNA interference (RNAi) and catalytic RNA molecules, called ribozymes, are being developed to modulate expression of genes to either block tumourigenesis itself, inhibit tumour growth or prevent metastasis. Delivery of mRNA or vectors based on positive-strand RNA viruses such as alpha viruses, picornaviruses and flaviviruses have also found applications in the development of cancer vaccines and for apoptosis of tumour cells. These approaches should help overcome some of the drawbacks of viral vectors used in the majority (~ 60%) of clinical trials for cancer gene therapy, including potential malignant transformation due to insertional mutagenesis with retroviral delivery and pre-existing immune responses to adenoviral proteins. In this review, the advantages and disadvantages of RNA-based therapeutic strategies and their potential use in cancer treatments will be compared.     

Polyethylenimines for RNAi-mediated gene targeting in vivo and siRNA delivery to the lung

RNA interference (RNAi) is a promising strategy to inhibit the expression of pathologically relevant genes, which show aberrant (over-)expression, e.g. in tumors or other pathologies. The induction of RNAi relies on small interfering RNAs (siRNAs), which trigger the specific mRNA degradation. Their instability and poor delivery into target tissues including the lung, however, so far severely limits the therapeutic use of siRNAs and requires the development of nanoscale delivery systems. Polyethylenimines (PEIs) are synthetic polymers, which are able to form non-covalent complexes with siRNAs. These nanoscale complexes (’nanoplexes’) allow the protection of siRNAs from nucleolytic degradation, their efficient cellular uptake through endocytosis and intracellular release through the ’proton sponge effect’. Chemical modifications of PEIs as well as the coupling of cell/tissue-specific ligands are promising approaches to increase the biocompatibility, specificity and efficacy of PEI-based nanoparticles.This review article gives a comprehensive overview of pre-clinical in vivo studies on the PEI-mediated delivery of therapeutic siRNAs in various animal models. It discusses the chemical properties of PEIs and PEI modifications, and their influences on siRNA knockdown efficacy, on adverse effects of the polymer or the nanoplex and on siRNA biodistribution in vivo. Beyond systemic application, PEI-based complexation allows the local siRNA application to the lung. Biodistribution studies demonstrate cellular uptake of PEI-complexed, but not of naked siRNAs in the lung with little systemic availability of the siRNAs, indicating the usefulness of this approach for the targeting of genes, which are pathologically relevant in lung tumors or lung metastases.Taken together, (i) PEI and PEI derivatives may represent an efficient delivery platform for siRNAs, (ii) siRNA-mediated induction of RNAi is a promising approach for the knockdown of pathologically relevant genes, and (iii) when sufficiently addressing biocompatibility issues, the locoregional delivery of PEI/siRNA complexes may become an attractive therapeutic strategy for the treatment of lung diseases with little systemic side effects.     

靶向P75NTR的siRNA技术诱导U251胶质瘤细胞凋亡的实验研究

目的:利用靶向P75神经营养因子受体(P75NTR)基因的小干扰(siRNA)技术诱导胶质瘤凋亡.方法:利用脂质体介导P75NTR-siRNA质粒转染U251胶质瘤细胞系,RT-PCR方法检测P75NTR的mRNA表达以确定基因沉默效果,绘制细胞生长曲线,原位细胞凋亡实验检测细胞凋亡情况,Western blot方法检测稳定转染后第3天时P75NTR、促凋亡基因Caspase-3和凋亡抑制基因Bcl-2的蛋白表达.结果:转染P75NTR siRNA质粒后U251细胞P75NTR的mRNA表达水平显著下降,细胞增殖能力下降,凋亡细胞数量增加.与对照组和空载组比较,P75NTR与Bcl-2在RNAi组蛋白表达水平显著降低,Caspase-3则明显升高.结论:靶向P75NTR的siRNA技术可通过调控凋亡相关基因表达机制诱导胶质瘤细胞凋亡.