Amid the national debate over stem cells and therapeutic cloning, there’s another biomedical technology that is showing increasing promise without the ethical conundrums. RNA interference (RNAi) is a natural regulatory process in which small, double-stranded RNA molecules turn off specific genes in a cell. Because RNAi is highly targeted and efficient, it has become a widely used tool for understanding what genes do and how they work. But its real payoff lies in new therapies – and developing them will require a renewed commitment to funding and research.
Exploiting the properties of RNA molecules could yield more-effective drugs to fight cancer, HIV, influenza, and other diseases. Rather than blocking the effects of specific proteins, which is what conventional drugs do, an RNAi-based therapy could in theory stop the proteins from being made in the first place. Mark Kay, director of the Program in Human Gene Therapy at the Stanford University School of Medicine, calls RNAi “incredibly robust technology with incredible therapeutic potential” but cautions that it’s in a “very new, very early stage.”
Indeed, the main hurdle so far has been the delivery of RNAi therapies in the body: RNA molecules tend to degrade quickly in the bloodstream and are not easily taken up into cells. But as we report in this month’s “Synopses” (see “Cholesterol Cure?”), researchers have now demonstrated that RNAi techniques can lower cholesterol levels in mice. The key advance: chemically modifying synthetic RNA molecules so that they remain potent after being injected into the blood. Major challenges remain to be met before RNA molecules begin to yield drugs, but this is a critical advance and an encouraging, albeit early, indication of the therapeutic potential of this kind of treatment.
In the past few years, the RNAi field has benefited from generous funding and the work of hundreds of scientists in the United States and abroad. RNAi companies such as Alnylam Pharmaceuticals and Benitec are conducting animal tests and moving toward clinical trials. At the National Institutes of Health, there are ongoing discussions about funding multi-institutional RNAi centers to encourage collaborative research.
But that’s not enough. We have closely followed the progress of research on RNAi ever since its therapeutic potential became clear (see “Prescription RNA,” December 2002/January 2003). It may be early, but the time is right for an international “moonshot” project in which academics, clinicians, and companies collaborate. The National Institutes of Health should weigh the recommendations of its working groups and set aside the funds for an initiative that will yield human testing of RNAi-based therapies within five years. There are different approaches – scientists disagree, for instance, on whether gene therapy techniques (using DNA “vectors”) or direct RNA delivery is most promising – so the initiative should support them all. At the same time, scientists and the media should be careful not to exaggerate the propinquity of the technology but rather move forward with cautious, responsible optimism.