New research shows that giving aspirin to cancer patients along with immunotherapy could dramatically boost the effectiveness of the treatment.
Since its market release more than a century ago, aspirin has become one of the most widely used medications to treat pain, fever, and inflammation. Numerous studies have indicated that taking it daily reduces the risk of heart attack or stroke. In addition, some studies have concluded that taking aspirin on a regular basis may lower cancer risk. Recently, new research has suggested that aspirin could potentially increase the power of cancer immunotherapy treatments. How are the two linked?
Cancer cells produce large amounts of prostaglandin E2 (PGE2), which lowers the immune system’s normal response to attack tumors. PGE2 production allows tumors to thrive and evade the immune system, which may explain why some immunotherapy treatments have not been effective. Cyclooxygenase (COX)-1 and 2 are enzymes critical for the production of PGE2, and are often overexpressed in various cancers. Aspirin blocks COX-1 and COX-2, thereby stopping the production of PGE2. If you inhibit cancer cells’ ability to make PGE2, you might also block their immune evasion mechanisms and unleash the full power of the immune system.
Researchers at the Francis Crick Institute in London found that a combination of aspirin and an immunotherapy treatment slowed the growth of bowel and melanoma cancers in mice (1). Genetic ablation of COX or PGE2 synthases in mouse melanoma, breast, or colorectal cells using the CRISPR/Cas9 system resulted in reduced PGE2 levels and a much stronger immune response against the tumors. To determine whether aspirin could mimic the effects of knocking out the COX genes, aspirin was added to the drinking water of mice transplanted with colorectal or melanoma skin cancer cells. By itself, the drug had no effect. However, combining immunotherapy with aspirin promoted much more rapid tumor regression and significantly slowed down cancer cell growth compared to immunotherapy alone. Interestingly, the mice developed a strong “memory” and were immune to a subsequent challenge months later.
The findings of this study suggest that aspirin or other COX inhibitors could be useful additions to conventional treatment of cancer patients. HemaCare provides disease-state biological products, including those associated with various cancers.
 Zelenay, S. et al. Cyclooxygenase-Dependent Tumor Growth through Evasion of Immunity. Cell 162, 1257-1270, doi:10.1016/j.cell.2015.08.015 (2015).