EUREKA project E! 3371 Gene Transfer Agents has achieved much progress in the development of new non-viral carriers that are able to introduce genetic material in the target cells. These novel agents, which are in fact derivatives of cationic amphiphilic 1,4-dihydropyridine (1,4-DHP), prevent the troubles of the patient’s immune system reacting against a viral carrier. The project partners have worked out ways to produce them in great amounts that solves another of the difficulties with viral delivery. However, the greatest benefit is that the novel compounds are considerably more efficient at delivering DNA into cell nuclei than other regular synthetic carriers; thus rising the chance of the DNA fruitfully controlling the defective genes as well as the disease. Gene therapy comprises of inserting DNA into human cells in the body in order to treat the illness. This technique is yet in its initial days, and has been demonstrated productively only throughout the last ten years. The majority of investigation that has been conducted was regarding the possibilities for treating hereditary illnesses that are in relation to a genetic defect, and the technique has prospective uses in the treatment of early stages on cancer, in neurodegenerative and cardiovascular diseases too.
As a practical method, gene therapy faces various difficulties; one of them being the fact that DNA is a big and complex structure that requires to be delivered as well as attached to the right section of the patient’s set of DNA. Some of the methods are currently being made use of or under investigation for the introduction of DNA into cells (a process called transfection) – using chemical agents, viruses or physical injection.
Viruses or chemical carriers
By the means of viral carriers, the DNA to be introduced is inserted into the virus, which in turn carries it into the cells through a vesicle formed around the virus particle by the cell wall. As soon as it is inside the cell, the vesicle breaks down and the virus introduce the DNA into the cell’s nucleus. However, the viral route comprises of some major disadvantages. Often, there is interference by the immune system of the recipient with the viral activity; and viruses can have unanticipated mutagenic side-effects. Moreover, it is also problematic to produce viral vectors on a large scale.
There is already a wide range of chemical agents that are famous for their ability to form a complex of 1,4-DHP with DNA and deliver it into the cells of the person receiving the treatment. The large scale production of these agents is far much easier compared to viruses and also do not often cause an immune response. Nevertheless, they are not so efficient in the introduction of the DNA as the viral carriers.
Seeking the best of both worlds
The partners in the EUREKA project faced the challenge to combine the efficiency of the viral vectors with the production benefits and lack of immune response demonstrated by chemical agents. The scientists at the University of Kuopio and the Latvian Institute of Organic Synthesis, in Finland had found out novel groups of probable DNA transfers agents; 1,4-DHP derivatives. These compounds were recognised as being far more effective in gene transfer that the two much used regular gene delivery agents, called DOTAP and PEI 25, and the finding was covered by a patent. This discovery provided the thrilling prospect of more efficiency from a non-viral carrier.
In accordance with Professor Arto Urtti, from the Helsinki University (previously from Kuopio), when these compounds are in solution and the DNA is introduced, they combine together. The large and loose DNA molecule collapses and small particles of around 10-50nm in diameter are formed, made up of both DNA and carrier. When one presents this to the cells, the nanoparticles bind to the surface of the cell, which thereafter folds inwards in order to form a vesicle in the cell. Subsequently, the particles escape from the vesicle, and in this action, release the DNA.
The researchers of the Helsinki University discovered that out of all the compounds that have been tested, the most effective ones were those which were successful in transferring DNA into the nucleus. While the mechanism by which the DNA enters into the nucleus still remains unclear, it is however known that gene transfer is more efficient in cells which are keenly dividing, for instance, cancer cells.
Doctor Arkadijs Sobolevs, Doctor Aiva Plotniece along with their colleagues of the Latvian Institute then started out to synthesise a number of varied DHP derivative compounds. In accordance with Doctor Plotniece, the huge benefit of these compounds is the 1,4-DHP fragment that is biologically active, which is a correct substitution, can demonstrate specific physico-chemical and biological properties. They have throughout this project designed diverse 1,4-DHPs that permitted them to establish structure-activity relationships.
The autonomous Latvian chemical producer Bapeks, who is the third project partner, contributed its experience in relation to large scale synthesis and advised the researchers of the Latvian Institute on the best way to scale up the synthesis methodology. Thereafter, the compounds were distributed to various other research colleagues in Lithuania, Finland and Latvia for more in-depth study. At the moment, the project partners think that the principal uses will be made during laboratory experiments and far much more research is required before they can be used for gene therapy in human beings.
The partners in the EUREKA project are of view that even though more research is required, the project has been a successful one. Doctor Sobolevs says that it was the initial big, crucial project for them. He affirms that they have considerably widened the prospective uses of self-assembling 1,4-dihydropyridine derivatives into nanomedicine, gene delivery and even in drug delivery systems. The project team discovered that EUREKA support assisted hugely in the preparation, management and reporting of the project. Moreover, it was through EUREKA that the various other partners were introduced to Bapeks.
Source: Escience News and Eureka Network
Sat, Jun 26, 2010
Bioscience, Immortality, Longevity, Stem cells