Info Technology World Wide

Part Two, Number 7

Technological applications in the tech area of "RNAi Therapy".

7. RNAi Therapy: From heart disease to hepatitis, cancer to AIDS, a large number of modern ailments are triggered by errant genes; or by those of invading organisms. So if a simple technique could be found for turning off specific genes at will, these diseases could (in theory) be arrested or cured.

So with RNA interference (RNAi), someone has discovered that tiny double-stranded molecules of RNA designed to target a certain gene can, when introduced into human cells, specifically block that gene's effects.

RNAi is much more potent and reliable than earlier methods. Now the technique has universal acceptance; encouraging research at every major drug company and university.

The implications of RNAi are breathtaking, because living organisms are largely defined by the exquisitely orchestrated turning on and off of genes; for example, a cut on a finger activates blood-clotting genes, and clot formation in turn shuts them down.

Pharmaceutical companies are already using RNAi to discover drug targets, by simply blocking the activity of human genes, one by one, to see what happens. If, for instance, a cancer cell dies when a particular gene is shut down, researchers can hunt for drugs that target that gene and the proteins it encodes.

Now drug companies, along with biotech startups and academic researchers, are seeking to use RNAi to treat disease directly. Silencing a key gene in the HIV virus could stop it from causing AIDS; knocking out the mutated gene that causes Huntington's could halt the progression of the disease; and turning off cancer genes could shrink tumors. The interference process works by preventing the gene from being translated into the protein it encodes. Proteins do most of the real work of biology.

Normally, a gene is transcribed into an intermediate "messenger RNA" molecule, which is used as a template for assembling a protein. When a small interfering RNA molecule is introduced, it binds to the messenger, which cellular scissors then slice up and destroy.

The biggest hurdle to transforming RNAi from laboratory aide to medicine is delivering the RNA to a patient's cells, which are harder to access than the individual cells used in lab experiments. It could take a decade or longer to develop a system that effectively delivers RNAi drugs to large organs or the whole body. Assuming that the tiny RNA molecules can fulfill the promise of their fast start, traditional molecular biology will be completely changed from its current expectations.