Significantly boosting the effectiveness of immunotherapy may be possible by giving cancer patients aspirin along with the treatment, new research from Francis Crick Institute finds. The study showed that skin, breast and bowel cancer cells often produce large amounts of prostaglandin E2 (PGE2).
The PGE2 molecule lowers the immune system’s normal response to attack faulty cells, which helps cancer to hide. It is a trick that allows the tumour to thrive and may explain why some immunotherapy treatments have not been as effective as hoped.
Aspirin is part of a group of molecules called COX inhibitors, which stop the production of PGE2 and help reawaken the immune system. Compared to immunotherapy alone, blending immunotherapy with aspirin or other COX inhibitors substantially slowed bowel and melanoma skin cancer growth in mice.
Professor Caetano Reis e Sousa, study author and senior group leader at the Francis Crick Institute, said:
“We’ve added to the growing evidence that some cancers produce PGE2 as a way of escaping the immune system. 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.
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. It’s still early work but this could help make cancer immunotherapy even more effective, delivering life-changing results for patients.”
The research was carried out in mice so it is still long before we will see patients being given COX inhibitors as part of their treatment, according to professor Peter Johnson, Cancer Research UK’s chief clinician.
Zelenay, S. et al
Cyclooxygenase-dependent tumor growth through evasion of immunity
Cell, 2015. DOI: 10.1016/j.cell.2015.08.015