US scientists say they have successfully tweaked a common heart drug to make it fight cancer.

Digoxin or digitalis, which comes from the foxglove plant, is normally used to steady the rhythm of the heart and help it beat more efficiently.

Now a University of Wisconsin-Madison team have changed some of its building blocks to make it target tumours.

The Proceedings of the National Academy of Sciences work provides hope other “natural” drugs can be manipulated.

Dr Jon Thorson and colleagues found they were able to change sugars attached to the drug.

The technique they used is called neo(new)-glyco(sugar)-randomisation.

It changes the way sugars are grouped on a drug, which, in turn, changes the way the drug works.

In the case of digitalis, switching around the sugars boosted its ability to target cancerous cells and kill them in the laboratory.

Ultimately, it might be possible to tweak the drug enough so it is able to treat cancer without having any effect on the heart, said Dr Thorson.

Wide scope

The neoglycorandomisation technique could also help doctors developing drugs for other diseases, he said.

“We’ve already taken this chemistry and applied it to many different classes.

“It’s possible to extend it to antibiotics and antivirals. If you want to plug a sugar and see what it does for you, this is the best way to do it,” he said.

Hazel Nunn of Cancer Research UK said: “This technique is an important biomedical advance, which could increase the chances of finding active drugs against cancer and a wide range of other conditions.

“But any drugs developed using this technique will need to go through rigorous clinical trials to determine their safety and effectiveness in humans.

“Although this research is exciting, the benefits for patients are likely to be a number of years away.”