By Pat Hagan
Last updated at 10:52 PM on 25th November 2011
Foxglove was one of the first plants to be used for the development of a pharmaceutical medicine
One of Britain’s best known flowering plants could soon be used to stop the spread of breast cancer.
Scientists in the U.S. have discovered that a drug based on foxglove, which produces distinctive tall spires of pink tubular bells in the summer, can dramatically slow the migration of malignant cells to other parts of the body.
Their research reveals that digoxin, a long-established drug based on chemicals found in foxglove, can block the production of a protein called HIF-1, which has been implicated in the spread of breast tumours.
Digoxin has been used for decades to treat conditions such as congestive heart failure and irregular heartbeats.
But the latest discovery, by a team at Johns Hopkins University in Baltimore, USA, suggests the cheap and easily available medicine could also be deployed in the fight against cancer.
Earlier this year the same team found it could reduce the spread of prostate cancer in men by around 24 per cent.
‘This is really exciting,’ said research leader Dr Gregg Semenza, from the Institute for Cell Engineering at the university.
‘Our findings warrant clinical trials to determine if the doses (used in animal studies) are enough to sufficiently block HIF-1 and slow breast cancer growth and spread.’
Foxglove was one of the first plants to be used for the development of a pharmaceutical medicine.
In 1785, country doctor William Withering noticed a remarkable improvement in a patient with congestive heart failure after they took a traditional herbal remedy made from the plant.
He identified that the active ingredient was a substance called digitalis and wrote about his findings more than 200 years ago in a book entitled ‘An account of the foxglove and some of its medical uses’.
Drug company giants like GlaxoSmithKline eventually turned it into a tablet called digoxin, used for heart failure as well as atrial fibrillation, an abnormal heart rhythm.
The research is still in its early stages and clinical trials are needed to see if the drug can slow breast cancer growth and spread in humans
But in recent months, new evidence has emerged that the traditional remedy could also play a vital role in treating cancer.
In April, the Johns Hopkins research team reported the results of a study involving 47,000 men in the journal Cancer Discovery.
These showed the drug appeared to stop the growth of prostate cancer in nearly one in four men.
But researchers warned this did not yet provide proof that digoxin was responsible for the benefits and warned against the drug, which can have side-effects such as nausea, headache and breast enlargement in men, being given to healthy people to prevent tumours.
Laboratory tests show digoxin appears to hinder the production of HIF-1, a protein that controls the genes which allow cancer cells to survive in low-oxygen environments, such as deep inside a solid tumour.
The tests showed those given digoxin – the drug developed from the flower – had fewer cancer cells spread to the lungs, one of the major sites that breast tumours migrate to
Experiments have also revealed that in women with breast cancer, an increase in HIF-1 levels is closely linked to metastasis – the spread of tumour cells – and a reduced likelihood of survival.
To see how the HIF-1 protein behaved when exposed to digoxin, researchers transplanted human breast cancer cells into mice and, two weeks later, gave them daily injections of either the drug itself or saline.
The results showed those given digoxin had fewer cancer cells spread to the lungs – one of the major sites that breast tumours migrate to – and tumours that had spread were smaller than in the saline group.
The findings could be even more significant because the research team found evidence that cancer cells start to spread from the breast to the lung much earlier than was previously thought.
This could mean that if further trials confirm the benefits of the drug, it’s possible it could be routinely used in women with aggressive tumours to try and reduce the risk of them spreading.
Around 48,000 women in Britain are diagnosed with breast cancer each year, equal to around 130 a day. A woman has a one in nine chance of developing the disease at some point in her life.
Dr Caitlin Palframan, from Breakthrough Breast Cancer, stressed the research is still in its early stages and clinical trials are needed to see if the drug can slow breast cancer growth and spread in humans.
‘However, it is exciting as digoxin has been used for decades in medical treatment with a proven safety record. We hope it means clinical trials will move quickly, allowing us to learn more about whether this approach will work to help prolong lives.’