Empty virus-like particles (eVLPs) as bio-compatible targeted drug-delivery vehicles

空病毒样颗粒（eVLP）作为生物相容性靶向药物递送载体

基本信息

批准号：
BB/I002294/1
负责人：
George Lomonossoff
金额：
$ 45.98万
依托单位：
John Innes Centre
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FI002294%2F1
关键词：
Empty virus like particles eVLPs

项目摘要

A major challenge in pharmacology is to devise methods whereby drugs can be delivered specifically to target tissues. This is a particular issue in the case of anti-cancer drugs which usually discriminate between cancerous and normal cells by the fact that the cancer cells are dividing more rapidly. However anti-cancer drugs are toxic to all cells and thus often have severe side-effects. To avoid this, it would clearly be desirable to target the drug molecule specifically to the cancerous tissue. A potential means of achieving this would be to package or encapsulate the drug molecules inside a particle which is designed to bind solely to the cancerous tissue. Such encapsulation would have the additional advantage of protecting the drug from breakdown in blood plasma. For this to become a reality it will be necessary to develop particles which can be modified on their outer surface to achieve the desired targeting and which can contain drug molecules. The particles need to be small enough to be able to move in the bloodstream, are not toxic and to be able to enter cells. One type of particle which has all these characteristics is the plant virus, cowpea mosaic virus (CPMV), which can be produced in large quantities by infecting plants. Previous research has shown that it is possible to 'stick' molecules on the surface of CPMV particles which enable them to be targeted to specific cells. Despite these advantages, CPMV particles have not, to date, been exploited as a drug-delivery vehicle. The reason for this is that particles produced by the infection of plants are already filled with the virus' own genetic material. This means that there is little or no room to put anything else, such as drug molecules, inside the particles. Even if such molecules could somehow be squeezed in, there would still be concerns about administering particles containing viral genetic material, even though it is from a plant virus that cannot infect animals. This project addresses the issue of the genetic material within the virus particles by exploiting the recent discovery at the John Innes Centre of a method of producing large quantities of pure empty (lacking genetic material) virus-like particles (eVLPs) of CPMV in plants. The method involves simultaneously expressing genes coding for a precursor of the viral coat proteins and the enzyme used to process it using a recently developed highly efficient plant transient expression system. Applying this approach we will produce particles which are modified so that they will specifically bind to proteins expressed on the surface of cancerous, but not normal, cells. This modification will be done either chemically or by making genetic fusions to the virus coat protein. We will investigate the best way of loading the targeted particles with the anti-cancer drug, gemcitabine. To do this we will make use of pores in the virus particles which allow small molecules to enter under certain conditions. The ability of the targeted particles to deliver the drug to cancer cells will be investigated by testing their ability to bind to and kill cancers in culture. This will be the first important step in potentially developing brand new therapeutic agents to tackle human cancer.

药理学的主要挑战是设计方法，可以将药物专门传递给靶组织。对于抗癌药物的情况下，这是一个特殊的问题，通常通过癌细胞更快地分裂癌细胞和正常细胞。但是，抗癌药对所有细胞都有毒性，因此通常具有严重的副作用。为了避免这种情况，显然希望将药物分子专门针对癌组织。实现这一目标的一种潜在手段是将药物分子包装或封装在粒子内，该粒子旨在仅与癌组织结合。这种封装将具有保护药物免受血浆中分解的其他优势。为了使其成为现实，有必要开发可以在其外表面进行修改以实现所需靶向并包含药物分子的颗粒。颗粒需要足够小，以便能够在血液中移动，没有毒性并能够进入细胞。具有所有这些特征的一种类型的粒子是植物病毒，牛豆镶嵌病毒（CPMV），可以通过感染植物大量生产。先前的研究表明，可以将分子“粘在CPMV颗粒的表面上，这使它们能够针对特定的细胞。尽管有这些优势，但迄今为止，CPMV颗粒尚未被用作药物运输。原因是植物感染产生的颗粒已经充满了病毒自己的遗传物质。这意味着在颗粒内部几乎没有其他任何东西，例如药物分子。即使可以以某种方式挤进这样的分子，即使它来自无法感染动物的植物病毒，仍然会担心施用含有病毒遗传物质的颗粒。该项目通过利用John Innes中心的最新发现来解决病毒颗粒中遗传物质的问题，该方法是一种产生大量纯净（缺乏遗传物质）病毒样颗粒（EVLP）CPMV的方法。该方法涉及同时表达编码病毒涂层蛋白前体的基因，并使用最近开发的高效植物瞬态表达系统来处理它的酶。采用这种方法，我们将产生经过修改的颗粒，以便它们特异性结合在癌细胞表面但不是正常细胞表面表达的蛋白质。这种修饰将通过化学或通过对病毒外套蛋白进行遗传融合来进行。我们将研究使用抗癌药吉西他滨加载靶向颗粒的最佳方法。为此，我们将利用病毒颗粒中的孔，这些孔使小分子在某些条件下进入。靶向颗粒将药物输送到癌细胞的能力将通过测试其与培养物结合和杀死癌症的能力来研究。这将是潜在开发全新治疗剂来解决人类癌症的第一步。