How Do RNA Interference Drugs Work?

A new drug discovery field called RNA interference is hot, hot, hot these days. According to current theory, small snippets of RNA with just the right sequence should be able to interfere with the expression (translation) of genes with the corresponding complementary nucleotide sequence. Drug companies are racing to find the RNA sequences that would inactivate specific disease-causing genes. Presumably the therapeutic effect would be highly specific, since only certain genes would be inactivated.

But is that how the RNA interference drugs currently under development actually work? New evidence just published online in Nature on March 26 (doi:10.1038/nature06783) suggests that the drugs may be working by a much more general mechanism – activation of the immune system. If so, the drugs may have side effects that have not yet been considered. The findings were such a surprise that the stock prices of small companies working on RNA interference drugs went down briefly.

The Nature article is for experts only. For students, I suggest the more general New York Times article published online on Apr. 2 (“Study is Setback for Some RNA-Based Drugs”, http://nytimes.com/2008/04/02/business/02place.html).