Small interfering RNA (siRNA) research has advanced significantly in the past decade but the lack of an efficient delivery system has been a barrier to creating therapeutics.
A paper in the special edition details these barriers and an understanding of them has led to a template for overcoming the challenges, which was explained by Kun Cheng, Division of Pharmaceutical Sciences, University of Missouri and Ram Mahato, Department of Pharmaceutical Sciences, University of Tennessee Health Science Center.
They said: “Generally, an efficient siRNA delivery system includes a cationic group for ionic interaction with siRNA, poly(ethylene glycol) (PEG) for steric hindrance, an endosomolytic group for endosomal disruption, and a targeting ligand for site-specific delivery.”
These are reviewed in the publication, which says that targeted, self-assembled nanoparticles have shown potential in treating cancer.
Self-assembly has been the most successful technique so far, with nanoparticles developed this way being the first targeted siRNA to enter clinical trials.
Other techniques covered in the research papers include light controlled delivery, which has the potential to enable temporal and spatial control targeting. This is achieved by adding a compound to the siRNA that silences its activity until activated by light.
There are currently 12 siRNA treatments in clinical trials, eight of which are for local delivery. The number of publications related to RNAi has risen from five in 1998 to 2400 last year.
