RNAi技术的应用

RNAi技术是一种新兴的由外源性或细胞内源性的双链RNA介导的转录后基因沉默技术.通过RNAi技术,目标基因一般可以低表达或完全不表达.目前RNAi技术在基因功能、发育生物学和基因治疗方面的研究有了广泛的应用.     

RNAi在癌症治疗中的应用

1998年，Fire等发现当外源双链RNA(dsRNA)分子被注入线虫体内后能导致其同源基因沉默，他们把这种现象称为RNA干扰(RNA interference，RNAi)。RNAi是生物界普遍存在的一种调控基因表达的有效方式和鉴定基因功能的重要手段，与植物体内的转录后基因沉默及真菌体内基因抑制有密切联系。RNAi由长约21—23个核苷酸的双链RNA分子(siRNA，small interfering RNA)介导，以序列特异的方式抑制同源基因的表达，其副作用也很小，这是siRNA在基因治疗方面的重要优势。因此，RNAi可在疾病的预防和治疗中起重要的作用。     

RNA干扰技术应用新进展

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。     

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.     

RNAi的分子机制及其应用的研究进展

RNA干扰（RNA interference,RNAi）是最近几年发现和发展起来的一门新兴的在转录水平上的基因阻断技术。它与反义RNA技术有很大不同，是一种双链RNA（Doublestranded RNA,dsRNA）分子在mRNA水平上关闭相应序列基因的表达或使其沉默的过程，也就是序列特异性的转录后基因沉默。     

基因药的研究与应用进展

基因药物的研究主要针对致病基因的DNA和基因转录本mRNA两大类生物大分子.本文讨论了基因疫苗、反义核酸、肽核酸(PNA)、RNA干涉(RNAi)、等几种新型基因药物,并介绍了它们在基因治疗中的应用.     

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。     

RNAi在神经退行性疾病发病机制及防治研究中的应用

RNA干扰（RNA interference，RNAi）技术能特异性降解mRNA，沉默靶基因，在转录后水平抑制基因的表达，从而可用来进行基因功能的分析和药物靶标的研究。RNAi技术日趋成熟，已被广泛应用于生命科学的各个领域。在神经科学上，尤其是在神经退行性疾病，如阿尔茨海默病、帕金森病、亨廷顿病、脊髓小脑性共济失调、肌萎缩性侧索硬化症、朊病毒病等的研究中取得了显著进展，RNAi的应用为神经退行性疾病发病机制的揭示和治疗另辟了蹊径。     

RNA干扰的机制及生物学意义

RNA干扰(RNAi)是指外源或内源性的双链RNA(dsRNA)进入细胞后引起与其同源的mRNA特异性降解，因而抑制相应基因表达，表现出特定基因缺失表现的现象。它与植物中的共抑制或转录后基因沉默、真菌中的基因压制一样。均是生物体内普遍存在的、在RNA水平上调节基因表达的方式。作为一种古老的、进化保守的基因沉默机制，对细胞防御病毒的感染、     

RNA interference and its therapeutic potential

RNA interference is a technique that has become popular in the past few years. This is a biological method to detect the activity of a specific gene within a cell. RNAi is the introduction of homologous double stranded RNA to specifically target a gene’s product resulting in null or hypomorphic phenotypes. This technique involves the degradation of specific mRNA by using small interfering RNA. Both microRNA (miRNA) and small interfering RNA (siRNA) are directly related to RNA interference. RNAi mechanism is being explored as a new technique for suppressing gene expression. It is an important issue in the treatment of various diseases. This review considers different aspects of RNAi technique including its history of discovery, molecular mechanism, gene expression study, advantages of this technique against previously used techniques, barrier associated with this technique, and its therapeutic application.     

Potentiality of small interfering RNAs (siRNA) as recent therapeutic targets for gene-silencing

In recent years, RNA interference (RNAi) is one of the most important discoveries. RNAi is an evolutionarily conserved mechanism for silencing gene expression by targeted degradation of mRNA. Short double-stranded RNAs, known as small interfering RNAs (siRNA), are incorporated into an RNA-induced silencing complex that directs degradation of RNA containing a homologous sequence. siRNA has been shown to work in mammalian cells, and can inhibit viral infection and control tumor cell growth in vitro. Recently, it has been shown that intravenous injection of siRNA or of plasmids expressing sequences processed to siRNA can protect mice from autoimmune and viral hepatitis. In this review, we have discussed about the discovery of RNAi and siRNA, mechanism of siRNA mediated gene silencing, mediated gene silencing in mammalian cells, vectored delivery of siRNA, pharmaceutical potentiality of siRNA from mice to human. We have also discussed about promise and hurdles of siRNA or RNAi that could provide an exciting new therapeutic modality for treating infection, cancer, neurodegenerative disease, antiviral diseases (like viral hepatitis and HIV-1), huntington's disease, hematological disease, pain research and therapy, sarcoma research and therapy and many other illness in details. It will be a tool for stem cell biology research and now, it is a therapeutic target for gene-silencing.     

RNA interference may be more potent than antisense RNA in human cancer cell lines

1. RNA interference (RNAi) is a newly discovered cellular pathway for the silencing of sequence-specific genes at the mRNA level by the introduction of the cognate double-stranded (ds) RNA. Because antisense (AS) mechanisms have similar effects, we compared these two effects in human cancer cell lines, considering a possible application of RNAi for cancer therapy. 2. We tested RNAi effects by transfecting human hepatoma and pancreatic cancer cell lines with AS and sense (S) RNA expression plasmids corresponding to the exogenous luciferase gene or the endogenous c-raf gene in the form of complexes with a cationic lipopolyamine or a tumour-targeting peptide vector we developed. In addition, we compared the effects of small interfering RNA and AS oligoDNA complexed with the peptide vector. 3. From the viewpoint of AS actions, the effect of the AS RNA may be cancelled by the S RNA, although, interestingly, we found that the combination of the AS and S RNA expression plasmids was more effective than the AS RNA expression plasmids alone in reducing target gene expression, whereas the S RNA expression plasmids had no effects. The combination of the luciferase AS and S RNA had no effects on the expression of either the beta-galactosidase gene or the c-raf gene. In the presence of 2-aminopurine (an inhibitor of dsRNA-activated protein kinase), the inhibitory effect of the combination of AS and S RNA on gene expression did not change in the case of the endogenous c-raf gene, but was reduced in the case of the exogenous luciferase gene. The effect of 22 nucleotide RNA duplexes corresponding to the luciferase gene was by one order stronger than that of the phosphorothioate AS DNA. 4. Thus, it is suggested that RNAi may be more potent than AS RNA in reducing target gene expression in human cancer cell lines, regardless of the length of dsRNA. With further studies on the RNAi phenomenon in cancer cells, RNAi could provide a novel approach for cancer gene therapy.     

Can siRNA technology provide the tools for gene therapy of the future?

A new era in genetics has started 15 years ago, when co-suppression in petunia has been discovered. Later, co-suppression was identified as RNA interference (RNAi) in many plant and lower eukaryote animals. Although an ancient antiviral host defense mechanism in plants, the physiologic role of RNAi in mammals is still not completely understood. RNAi is directed by short interfering RNAs (siRNAs), one subtype of short double stranded RNAs. In this review we summarize the history and mechanisms of RNAi. We also aim to highlight the correlation between structure and efficacy of siRNAs. Delivery is the most important obstacle for siRNA based gene therapy. Viral and nonviral deliveries are discussed. In vivo delivery is the next obstacle to clinical trials with siRNAs. Although hydrodynamic treatment is effective in animals, it cannot be used in human therapy. One possibility is organ selective catheterization. The known side effects of synthesized siRNAs are also discussed. Although there are many problems to face in this new field of gene therapy, successful in vitro and in vivo experiments raise hope for treating human disease with siRNA.     

Knocking down transport: applications of RNA interference in the study of drug transport proteins

RNA interference (RNAi) is a gene silencing process mediated by double-stranded RNA (dsRNA). The silencing process is comprised of an initiation step, in which small interfering RNA (siRNA) is introduced to the cell, and an effector step, which involves degrading mRNA molecules of the target gene. RNA interference has been observed in most organisms from plants to vertebrates. As a gene silencing approach, RNAi has proven to be extremely useful in characterizing gene function and developing new tools in cancer therapy and drug delivery. The development of RNAi-related technologies is an emerging area in biomedical research. In this review, recent progress in the application of RNAi to the study of transport proteins is summarized and evaluated; the advantages, disadvantages and future directions of RNAi technology are discussed.     

RNAi-based drug discovery and its application to therapeutics

The discovery of RNA interference (RNAi) for target-specific gene silencing via short interfering RNA (siRNA) has rapidly created a powerful tool for the exploration of pathogenesis of disease. The identification of this remarkable molecular pathway has manifested in the new field of RNAi therapy. In efforts to establish the therapeutic application of RNAi therapy, a major focus has been on target gene-specific siRNA-delivery technology in vivo. In particular, creating a pinpoint delivery system for siRNAs is a priority because such a system would be a key technology for the development of the next generation of drugs, including anticancer therapies. Drug discovery studies and novel treatments based on RNAi are currently targeting a wide range of diseases, including viral infections and cancer. This feature review focuses on recent progress in the nonviral systemic delivery of siRNA in animal models and in clinical trials, as well as on the application of microRNAs in RNAi therapy.     

Knocking Down Transport: Applications of RNA Interference in The Study of Drug Transport Proteins

RNA interference (RNAi) is a gene silencing process mediated by double-stranded RNA (dsRNA). The silencing process is comprised of an initiation step, in which small interfering RNA (siRNA) is introduced to the cell, and an effector step, which involves degrading mRNA molecules of the target gene. RNA interference has been observed in most organisms from plants to vertebrates. As a gene silencing approach, RNAi has proven to be extremely useful in characterizing gene function and developing new tools in cancer therapy and drug delivery. The development of RNAi-related technologies is an emerging area in biomedical research. In this review, recent progress in the application of RNAi to the study of transport proteins is summarized and evaluated; the advantages, disadvantages and future directions of RNAi technology are discussed.