Since I've previously discussed progress towards RNA interference (RNAi) therapies - more than once - and the way in which the future of medicine is all about better targeting, it seems appropriate to point out an advance that improves technology in both areas in one stroke. From the MIT Technology Review:
The main obstacles to using RNA interference to combat diseases, says John Rossi, chairman and professor of molecular biology at the Beckman Research Institute in Duarte, California, are ensuring that the RNA is taken up by the targeted cells so that it can do its work and that it is directed only at a tumor or a diseased area.
The Duke researchers' innovation was to design a region on the RNA itself that directs the therapy to the malignant cells. This directing region is called an aptamer, a section of RNA selected from a large pool of candidates for its ability to bind strongly to a particular molecule -- in this case, a protein that appears on the surface of some prostate cancer cells.
After the Duke RNA binds its target on the surface of prostate cancer cells, it is eventually dragged inside the cell. Once inside, the RNA is cleaved in two by a protein native to the cell, freeing the gene-silencing region to find and guide the destruction of its target. RNA interference leads to the destruction of the intermediary between DNA and proteins, called messenger RNA. The Duke therapy destroys the messenger for a gene whose protein prevents prostate cancer cells from dying, even when outside signals tell the cells to do so. With this protection removed, cancer cells died.
Very clever. In addition, it has the look of being more cost-effective to deploy than other targeting strategies, at least at the present time. Comparable strategies - such as those using nanoparticles or that attach theraputic agents to antibodies or other molecules - require additional steps and materials to be prepared.
The Duke RNA therapy can be made in one step, moves through tissue easily, and could in principle be designed to target any cell in the body