US researchers have taken a step forward in understanding how beta blockers may slow the spread of cancer.
The study is the latest in a series of findings that suggest the drugs, commonly used to treat conditions such as heart disease, high blood pressure, glaucoma and migraines, might also have a role to play in cancer treatment.
Previous studies have shown lower rates of death from various cancers among people who take beta blockers for long periods for other conditions, leading researchers to speculate that the drugs could help treat patients.
The new research, published in Nature Communications and led by Professor Anil Sood at the MD Anderson Cancer Center in Texas, focused on a molecule on the surface of cells, known as the beta-adrenergic receptor, or ADRB – the target of beta blocker drugs.
Working in a mouse model of ovarian cancer, the researchers showed that signals sent from ADRB into the cell’s interior activated a key cancer protein called Src.
This in turn switched on a variety of processes linked to the spread of the disease.
The effect was counteracted by giving the mice propanolol, a commonly used beta blocker, and this also appeared to slow the growth of the cancers.
“This is a major step forward in understanding [beta blockers’] biology and impact,” said Professor Sood. “It opens the door to study drugs that could inhibit this unique signalling pathway”.
To add further weight to their findings, the researchers looked at medical records from a large database called the Adverse Event Reporting System. They found that patients’ chances of dying from cancer were reduced by 17 per cent if they were also taking beta blockers for other conditions.
Dr Des Powe, a Nottingham-based researcher running a Cancer Research UK-funded study into beta blockers and breast cancer, agreed the evidence was becoming more and more compelling.
“Evidence has been building for several years that beta blockers could be used to help treat certain cancers – notably some forms of breast, bowel, lung, melanoma and ovarian cancer, and possibly prostate cancer.
“These cancers seem to have a more favourable prognosis in people who regularly take beta blockers, and trials are underway to find out more. On top of this, labs around the world have begun to work out exactly why and how this may be happening.”
But he cautioned that there was still a way to go before beta blockers – prescription drugs with known side effects – were proven safe and suitable for patients undergoing cancer treatment.
“This is an idea that needs to be fully tested in the clinic to be sure,” he warned.
- Armaiz-Pena G.N. et al. (2013). Src activation by β-adrenoreceptors is a key switch for tumour metastasis, Nature Communications, 4 1403. DOI: 10.1038/ncomms2413