基因药物纳米给药系统的设计与研究进展

基因药物的传递面临着体内外稳定性差、缺乏靶向性、难入胞、在细胞内难以释放等一系列障碍和挑战。因此,要实现基因药物在 体内有效传递需构建能克服这些障碍的药物传递系统。随着材料科学和纳米科技的发展,大量新型的纳米载体已被用于基因药物的传递。 综述目前基因药物传递所面临的障碍和挑战,基因药物纳米给药系统的设计思路及研究进展。     

抗体介导的靶向给药系统研究进展

本文简要综述了抗体介导的靶向给药系统的研究进展,包括抗体与药物的直接偶联、纳米粒、脂质体等的原理、特性以及药动药效学研究现状,并对其可行性和前景进行了分析。抗体介导的靶向给药系统不仅可以提高不溶或难溶性药物的溶解度,而且也可以提高靶部位的药物浓度,降低药物对全身各组织的毒副作用,增强对病变组织的治疗效果,为开发更高靶向效率、安全、经济、多类型的给药系统提供了借鉴。     

蛋白多肽类药物制剂的研究进展

相对于其他的给药途径,蛋白质多肽类药物的口服、经鼻、肺部给药途径更具可行性和商业价值。利用制剂学方法可提高蛋白质多肽类药物生物利用度。通过蛋白多肽类给药系统的评价,对近年来国内外此类药物在剂型、体内外稳定性及生物利用度等方面的研究进展予以综述。     

壳聚糖在给药系统中的应用

壳聚糖来源丰富,具有良好的生物相容性、生物可降解性、无毒性、成膜性和极强的可塑性,已经作为高分子材料,广泛用于给药系统中.将壳聚糖应用于给药系统中可以提高药物安全性、有效性及可靠性,可以调整药物释放速率,减少给药次数.此外,壳聚糖可塑性强,可制成膜、压成片、制成颗粒、微球或增粘剂等多种剂型.该文就壳聚糖的特性及其在给药系统中的应用予以综述.     

蛋白质药物口服的研究进展

蛋白质药物口服给药系统因其给药方便、顺应性好,逐渐成为一种最有前景的给药方式.从提高蛋白质药物生物利用度入手,综述采用结构修饰、吸收促进剂、酶抑制剂、结肠定位释药、脉冲式药物给药系统和受体介导靶向载体系统等方式,均可大大提高蛋白质药物的口服生物利用度和在胃肠道中的稳定性.     

载药脂质体的研究与应用进展

载药脂质体给药系统已成为国内外的研究热点。传统脂质体经修饰和改良后表现出良好的生物相容性,缓释性和靶向性。新型脂质体在经皮给药,肺部给药,脑部靶向治疗,基因治疗等方面的应用研究结果显示,集药物缓释、靶向于一体的具有良好生物安全性的脂质体给药系统具有很大发展潜力。本文综述了该领域中的最新研究进展。     

喷膜剂的研究进展

喷膜剂是一种结合喷雾剂和膜剂优点的外用给药新剂型,可用于抗菌、镇痛、精神和激素类药物的局部给药,尤其适合创面防护类药物,具有定量输出、给药便捷、顺应性好、提高药物生物利用度、实现靶向和缓控释给药的优点。本文通过检索近年来国内外相关文献、专利,从处方组成、制备工艺、质量控制、评价方法和研究方向等多个方面综述了喷膜剂的研究进展,为进一步优化药物的外用给药方式提供参考。     

超声靶向微泡破坏与载药/载基因纳米粒联合应用的生物物理学机制及应用研究进展

超声靶向微泡破坏(ultrasound-targeted microbubble destruction, UTMD)能够安全、高效、简便地递送药物与基因,是当前超声医学领域的研究热点,其机制主要涉及超声辐照微泡引起的空化效应及其二级效应、内吞作用与声辐射力。近年来,随着生物医学材料科学迅猛发展,纳米载药系统取材更加广泛,制备方法愈发精良,载药量日益提高。将纳米载药系统与UTMD进行联合,可以扬长避短,为肿瘤等多种疾病的治疗带来新的思路与希望。本文旨在对UTMD与载药/载基因纳米粒联合应用的生物物理学机制及应用研究进行综述并提出展望。     

新型药物递送系统研发格局分析

药物递送是通过特定的手段使活性药物成分有效地递送到目的部位,以在人类或动物中实现治疗效果的方法或过程。递送系统在控速给药、靶向给药、药物稳定性、生物相容性等方面具有重要的作用。近年来,随着药学、材料学和生物医学等相关领域的进步,从纳米尺度、细胞尺度到智能靶向递送等技术的发展使药物递送系统领域发生了巨大变化,新型药物递送系统的研究投入和市场份额持续快速增长。通过对不同载药系统的递送机制及特点进行阐述,系统梳理新兴药物递送系统技术的主要研究进展及企业竞争格局,并对相关技术的临床转化潜力和应用前景进行展望,为相关企业研发方向选择及决策提供参考。     

新型纳米靶向给药系统载体材料的设计

新型纳米靶向给药系统的研究与开发对于难治愈性疾病（尤其是肿瘤）的治疗具有重大意义,而其发展很大程度上取决于载体材料 的设计。构思巧妙、设计合理的载体材料能使载体实现靶向功能,将药物定位浓集于病灶部位,并最大限度地发挥高效低毒的作用。基于 不同的靶向策略,包括被动靶向、主动靶向和响应肿瘤微环境的靶向,综述了近年来一些新型纳米载体材料的设计,为新型纳米靶向给药 系统的研究提供参考。     

Non-viral gene therapy

Non-viral gene therapies are currently under development that employ drug-delivery methods for targeting genes to selected cells in the body, where they express therapeutic gene products. Various methods have been described for non-viral gene therapy, ranging from the direct intramuscular injection of purified DNA to the systemic administration of formulations comprising DNA and lipids, proteins, peptides, or polymers. Products for non-viral gene therapies are designed both for direct administration to patients by conventional routes and for expression of a therapeutic product over a finite period of time in a manner similar to conventional medicines. Initial preclinical and clinical studies indicate that non-viral gene delivery methods exhibit safety profiles similar to conventional pharmaceutical or biological products. Clinical trials have been proposed, or are currently under way, to assess the applicability of non-viral gene therapy for a variety of disorders, including cystic fibrosis, cancer, and peripheral vascular disease. Non-viral techniques may soon allow gene therapy to be applied in clinical practice alongside conventional medicines for the treatment of common diseases.     

Electro-transfer of small interfering RNA ameliorated arthritis in rats

RNA interference provides the powerful means of sequence-specific gene silencing. Particularly, small interfering RNA (siRNA) duplexes may be potentially useful for therapeutic molecular targeting of human diseases, although novel delivery systems should be devised to achieve efficient and organ-specific transduction of siRNA. In the present study, we demonstrated that electro-transfer of a siRNA-polyamine complex made efficient and specific gene knockdown possible in the articular synovium. Targeted suppression of the tumor necrosis factor-alpha gene through this procedure significantly ameliorated collagen-induced arthritis in rats. Our results suggest the potential feasibility of therapeutic intervention with RNA medicines for treatment of rheumatoid and other locomotor diseases.     

Functional mechanism of Ginsenosides on tumor growth and metastasis

Ginsengs, has long been used as one medicinal herb in China for more than two thousand years. Many studies have shown that ginsengs have preventive and therapeutic roles for cancer, and play a good complementary role in cancer treatment. Ginsenosides, as most important constituents of ginseng, have been extensively investigated and emphasized in cancer chemoprevention and therapeutics. However, the functional mechanism of Ginsenosides on cancer is not well known. This review will focus on introducing the functional mechanisms of ginsenosides and their metabolites, which regulate signaling pathways related with tumor growth and metastasis. Ginsenosides inhibit tumor growth via upregulating tumor apoptosis, inducing tumor cell differentiation and targeting cancer stem cells. In addition, Ginsenosides regulate tumor microenvironment via suppressing tumor angiogenesis-related proteins and pathways. Structural modification of ginsenosides and their administration alone or combinations with other Chinese medicines or chemical medicines have recently been developed to be a new therapeutic strategy for cancer.     

Plants as sources of natural and recombinant anti-cancer agents

Herbal remedies were the first medicines used by humans due to the many pharmacologically active secondary metabolites produced by plants. Some of these metabolites inhibit cell division and can therefore be used for the treatment of cancer, e.g. the mitostatic drug paclitaxel (Taxol). The ability of plants to produce medicines targeting cancer has expanded due to the advent of genetic engineering, particularly in recent years because of the development of gene editing systems such as the CRISPR/Cas9 platform. These technologies allow the introduction of genetic modifications that facilitate the accumulation of native pharmaceutically-active substances, and even the production heterologous recombinant proteins, including human antibodies, lectins and vaccine candidates. Here we discuss the anti-cancer agents that are produced by plants naturally or following genetic modification, and the potential of these products to supply modern healthcare systems. Special emphasis will be put on proteinaceous anti-cancer agents, which can exhibit an improved selectivity and reduced side effects compared to small molecule-based drugs.     

Spatial and acoustic pressure dependence of microbubble-mediated gene delivery targeted using focused ultrasound

BACKGROUND: Ultrasound/microbubble-mediated gene delivery has the potential to be targeted to tissue deep in the body by directing the ultrasound beam following vector administration. Application of this technology would be minimally invasive and benefit from the widespread clinical experience of using ultrasound and microbubble contrast agents. In this study we evaluate the targeting ability and spatial distribution of gene delivery using focused ultrasound. METHODS: Using a custom-built exposure tank, Chinese hamster ovary cells in the presence of SonoVue microbubbles and plasmid encoding beta-galactosidase were exposed to ultrasound in the focal plane of a 1 MHz transducer. Gene delivery and cell viability were subsequently assessed. Characterisation of the acoustic field and high-resolution spatial analysis of transfection were used to examine the relationship between gene delivery efficiency and acoustic pressure. RESULTS: In contrast to that seen in the homogeneous field close to the transducer face, gene delivery in the focal plane was concentrated on the ultrasound beam axis. Above a minimum peak-to-peak value of 0.1 MPa, transfection efficiency increased as acoustic pressure increased towards the focus, reaching a maximum above 1 MPa. Delivery was microbubble-dependent and cell viability was maintained. CONCLUSIONS: Gene delivery can be targeted using focused ultrasound and microbubbles. Since delivery is dependent on acoustic pressure, the degree of targeting can be determined by appropriate transducer design to modify the ultrasound field. In contrast to other physical gene delivery approaches, the non-invasive targeting ability of ultrasound makes this technology an attractive option for clinical gene therapy.     

植物基因打靶技术及其应用

本文对植物基因打靶技术的原理、操作程序、打靶效率的影响因素及其在植物中的应用现状进行了综述,并就如何有效的提高打靶效率提出了建议,同时对该技术在植物学研究领域中的应用前景进行了展望。     

Case studies of ends‐out gene targeting in Drosophila

Ends‐in and ends‐out gene replacement approaches have been successfully used to disrupt Drosophila genes involved in a variety of biological processes. These methods combine double‐strand breaks and homologous recombination to replace a targeted chromosome region with a designed DNA sequence. Unfortunately, these methods require large numbers of single animal crosses, making them both time consuming and labor intensive. Here, we designed a single complete targeting vector for use in a mass crossing ends‐out gene targeting study. Importantly, our gene targeting method included a balancer chromosome to block endogenous homologous chromosome pairing and to promote pairing between the foreign targeting DNA fragment and the targeted chromosome. This technique provided successful and efficient gene replacement, greatly facilitating the gene knockout procedure. genesis 47:305–308, 2009. © 2009 Wiley‐Liss, Inc.     

Effects of varying gene targeting parameters on processing of recombination intermediates by ERCC1-XPF

The ERCC1-XPF structure-specific endonuclease is necessary for correct processing of homologous recombination intermediates requiring the removal of end-blocking nonhomologies. We previously showed that targeting the endogenous CHO APRT locus with plasmids designed to generate such intermediates revealed defective recombination phenotypes in ERCC1 deficient cells, including suppression of targeted insertion and vector correction recombinants and the generation of a novel class of aberrant recombinants through a deletogenic mechanism. In the present study, we examined some of the mechanistic features of ERCC1-XPF in processing recombination intermediates by varying gene targeting parameters. These included altering the distance between the double-strand break (DSB) in the targeting vector and the inactivating mutation in the APRT target gene, and changing the position of the target gene mutation relative to the DSB to result in target mutations that were either upstream or downstream from the DSB. Increasing the distance from the DSB in the targeting vector to the chromosomal target gene mutation resulted in an ERCC1 dependent decrease in the efficiency of gene targeting from intermediates presenting lengthy end-blocking nonhomologies. This decrease was accompanied by a shift in the distribution of recombinant classes away from target gene conversions to targeted insertions in both wild-type and ERCC1 deficient cells, and a dramatic increase in the proportion of aberrant recombinants in ERCC1 deficient cells. Changing the position of the target gene mutation relative to the DSB in the plasmid also altered the distribution of targeted insertion subclasses recovered in wild-type cells, consistent with two-ended strand invasion followed by resolution into crossover-type products and vector integration. Our results confirm expectations from studies of Rad10-Rad1 in budding yeast that ERCC1-XPF activity affects conversion tract length, and provide evidence for the mechanism of generation of the novel, aberrant recombinant class first described in our previous study.     

1,5-isoquinolinediol increases the frequency of gene targeting by homologous recombination in mouse fibroblasts.

Gene targeting is a technique that allows the introduction of predefined alterations into chromosomal DNA. It involves a homologous recombination reaction between the targeted genomic sequence and an exogenous targeting vector. In theory, gene targeting constitutes the ideal method of gene therapy for single gene disorders. In practice, gene targeting remains extremely inefficient for at least two reasons: very low frequency of homologous recombination in mammalian cells and high proficiency of the mammalian cells to randomly integrate the targeting vector by illegitimate recombination. One known method to improve the efficiency of gene targeting is inhibition of poly(ADP-ribose)polymerase (PARP). It has been shown that PARP inhibitors, such as 3-methoxybenzamide, could lower illegitimate recombination, thus increasing the ratio of gene targeting to random integration. However, the above inhibitors were reported to decrease the absolute frequency of gene targeting. Here we show that treatment of mouse Ltk cells with 1,5-isoquinolinediol, a recent generation PARP inhibitor, leads to an increase up to 8-fold in the absolute frequency of gene targeting in the correction of the mutation at the stable integrated HSV tk gene.