One drug, multiple actions
Drug discovery is a laborious process, often involving a significant degree of trial and error in a medicinal chemistry lab. Historically, many of the best drugs were discovered with an element of luck, but getting lucky is not a reliable strategy.
Today, drugs are designed. The aim is usually to target one critical protein in the body, and avoid affecting any others to minimise potential side-effects. Many new cancer drugs have been developed this way: monoclonal antibodies are designed to target one specific protein in order to destroy cancer cells. However, some of these drugs have more recently been found to target other proteins related to the target, which has – fortunately – helped them to block the cancer cells’ activity. The multiple action of these drugs suggest that designing drugs to target more than one protein could be extremely useful, not just in cancer but in other areas including psychiatry.
Researchers at the University of Dundee and the University of North Carolina, part-funded by the Wellcome Trust, have created an algorithm that can design drugs that act on several proteins. After entering in the set of proteins you want the drug to target, the algorithm screens compounds to decide which are likely to do that. Simulating and screening chemical variations of these compounds, and then variations of the variations, means they can be ‘fine-tuned’ to discover which possible drugs would meet the desired targets to the best effect.
Every stage described so far is done on a computer, saving a lot of time and effort otherwise spent in a lab. It means you don’t have to synthesis every intermediate compound on the path to finding the best ones. Once identified, the leading contenders can be made and tested in real life.
Details of the research have been written about in Nature Reviews Drug Discovery and on In the pipeline, a blog which discusses the finer points of the chemistry, if you are interested. This kind of automated design system gives us a glimpse into the future of drug discovery, when we will be able to design a single drug to hit multiple therapeutic targets.
Besnard J, et al. (2012). Automated design of ligands to polypharmacological profiles. Nature, 492 (7428), 215-20 PMID: 23235874