John Murphy, MDLinx, 09/08/2015
Adding aspirin to immunotherapy could greatly improve cancer treatment, according to a new study published online September 3, 2015 in Cell.
Aspirin could halt cancer cells’ protective barrier and unleash the full power of the immune system.
The study builds on research that tumor cells are often able to evade the immune system, although how tumor cells do this is not fully understood. But prior research has found that cyclooxygenase (COX) in tumors produces prostaglandin E2 (PGE2), which is associated with enhanced cancer cell survival, growth, migration, and immunosuppression.
In this study, researchers determined that melanoma, colorectal, and breast cancers produce excess PGE2, which suppresses tumor immunity and induces inflammation associated with cancer progression.
“We’ve added to the growing evidence that some cancers produce PGE2 as a way of escaping the immune system,” said study author Caetano Reis e Sousa, DPhil, senior group leader at the Francis Crick Institute in London, U.K. “If you can take away cancer cells’ ability to make PGE2, you effectively lift this protective barrier and unleash the full power of the immune system.”
Asprin, a COX inhibitor, could stop the production of PGE2, which would prevent tumors from evading the immune system. When the researchers tested it in mice, they found that aspirin combined with an immune checkpoint blocker (anti-PD-1 monoclonal antibody) substantially slowed melanoma and colorectal cancer growth, compared with immunotherapy alone.
“Giving patients COX inhibitors like aspirin at the same time as immunotherapy could potentially make a huge difference to the benefit they get from treatment,” said Dr. Reis e Sousa. “It’s still early work but this could help make cancer immunotherapy even more effective, delivering life-changing results for patients.”