In a new study entitled “Cyclooxygenase-Dependent Tumor Growth through Evasion of Immunity” scientists at The Francis Crick Institute discovered that administrating aspirin (or other COX inhibitors) together with immunotherapies boosts the immune response against tumor cells. The study was published in the journal Cell.
Several types of tumor cells have developed ingenious ways to inhibit the action of immune responses. In this study scientists observed that melanoma cells produce prostaglandin E2 to suppress immunity and foster tumor-promoting inflammation. Because prostaglandins are synthesized by a group of enzymes, the cyclooxygenases (COX), researchers used genetic tools to inhibit COX in melanoma, breast or colorectal cancer cells, rendering these cells susceptible to the anti-tumoral action of the immune system.
Aspirin belongs to the family of COX inhibitors, as such, combining aspirin with immunotherapy (a treatment that works by boosting immune system responses against, in this case, cancer cells) significantly decreased cancer progression in mouse models for bowel and melanoma skin cancer.
These findings highlight the potential of COX inhibitors as adjuvants (i.e., a substance that increases the body’s immune response) for immunotherapies in cancer patients.
Professor Caetano Reis e Sousa, study lead author and senior group leader at The Francis Crick Institute commented, “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.”
Professor Peter Johnson, Cancer Research UK’s chief clinician added, “PGE2 acts on many different cells in our body, and this study suggests that one of these actions is to tell our immune system to ignore cancer cells. Once you stop the cancer cells from producing it, the immune system switches back to ‘kill mode’ and attacks the tumor. This research was carried out in mice so there is still some way to go before we will see patients being given COX inhibitors as part of their treatment. But it’s an exciting finding that could offer a simple way to dramatically improve the response to treatment in a range of cancers.”