Chest pain drug may have cancer benefits*
Thandi Fletcher, National Post
A common drug used to treat chest pain could help boost the body’s immune response to destroy some cancers, say researchers at Queen’s University in Kingston.
Nitroglycerine, a relatively safe and cheap drug used to treat angina, or chest pain, could help prevent the growth of cancer cells that escape detection by the body’s natural immune response.
The “exciting” findings show nitroglycerine could be useful, not only in treating some cancers, but also as a preventive measure to stop cancer cells from growing and dividing in the first place, said Charles Graham, the study’s senior author and a Queen’s biomedical and molecular sciences professor.
“The good thing about nitroglycerine is that it’s a drug that has been around for the treatment of angina since the 1870s,” he said. “It has an excellent safety profile and it has very few side effects.”
The study was published online Wednesday and will appear in a future issue of the peer-reviewed journal Cancer Research.
The researchers looked at cancer cells with hypoxia, a condition in which cells are deprived of adequate oxygen levels. They used mice and cancer cells in a petri dish for the tests.
As cancer tumours grow, they often outgrow their blood supply and have portions with low oxygen levels.
This makes the tumours incredibly resistant to chemotherapy and radiation treatment and allow them to spread to other parts of the body more easily.
The researchers found hypoxic cancer cells were linked to the overproduction of an enzyme that makes them resistant to being detected and attacked by immune cells.
But when the cancer cells were treated with nitroglycerine, the hypoxia was overcome. The cancer cells lost their resistance to the immune cells.
“One could imagine that by blocking the activity or the production of this enzyme it would be possible to boost the immune system’s ability to recognize and destroy cancer cells,” said Prof. Graham.
Wednesday’s study was a followup to an earlier study from Prof. Graham and his team.
That study, published in 2009 in the medical journal Urology, looked at the role of nitroglycerine in suppressing tumour growth in prostate cancer survivors whose cancer had returned.
The clinical trial was the first ever to consider using low doses of nitroglycerine to treat prostate cancer. The researchers were successful in stabilizing the PSA levels (a blood marker used to test for prostate cancer) of people in the study.
For more than a century, nitroglycerine has been prescribed as a heart medication to treat angina, often a symptom of heart disease. It can be given through a skin patch, a pill dissolved under the tongue, an ointment or intravenously.
One of its side effects is that some people develop severe headaches. Another problem is the body can develop resistance to its effects if given consistently for a lengthy period of time.
However, Prof. Graham said the incredibly low doses used for cancer patients would likely not result in drug resistance. They could also experience fewer side effects from the low dose.
* This is one of the media coverage for the research done by me and others in Dr. Graham Lab at Queen’s University.