Artificial virus for 'tailor-made gene therapy'

The potential for utilising viruses to deliver drugs and in gene therapy has been recognised for some time but has been held back as the viruses created were the wrong size and shape for drug delivery. By adopting a different technique for viral creation the researchers from Yonsei University in Seoul, Korea claim to have got round the difficulties encountered previously and created a filamentous artificial virus. Speaking to in-PharmaTechnologist.com Dr Yong-beom Lim, first author of the paper, said: "One of the advantages of our artificial virus is that, compared to conventional gene carriers, its shape is filamentous. ​ ​"Given the previous finding that a filamentous nanostructure persists longer than a spherical one, it can be expected that the filamentous artificial virus can be developed as long-lasting carrier for in vivo gene therapy​." Other research groups have created viruses by using polyion coupling but the products frequently aggregate and it is hard to develop viruses of a specific size. To avoid these problems the researchers used pre-organized supramolecular nanostructures to construct a filament-shaped artificial virus. The resultant virus is capable of binding to therapeutic agents and delivering them to targeted cells. The virus' binding and transfection capacity was tested by using small interfering RNA (siRNA), a double stranded RNA with potential in gene therapy. By using transmission electron microscopy the team established that the siRNA formed a complex with the virus. The transfection capability of the complex was then tested on human cervical cells and was found to be as effective as Lipofectamine 2000, a commercial transfection agent. In addition the structure of the virus enables it to encapsulate hydrophobic molecules and deliver them to cells. The virus was found to be capable of delivering both a hydrophobic molecule, a dye in this case, and siRNA into a cell. This dual delivery is useful when there are multiple causes of the cancer as "simultaneous delivery of anticancer drug (e.g. doxorubicin) and anticancer gene should improve the potency of anticancer therapy by targeting more than one oncogene​" according to Lim. Lim is now aiming to develop the virus to mimic more closely its natural brethren, which he regards as "experts in gene delivery​". He added: "The formation of a natural virus itself is the self-assembly process. Therefore, enabling ourselves to mimic natural viruses' self-assembly process in a useful, but not in a harmful way, should be the ultimate goal​."