Abigail Kelly, a research assistant at Harvard Medical School’s Beth Israel Deaconess Medical Center in Boston.
Research from various laboratories has suggested that Omega-3 fatty acids may help reduce cancer risk while consuming too much omega-6 fatty acids can promote cancer. Good sources of omega-3s include fish, nuts, and seeds while omega-6s are found in meat, eggs, and other foods.
In the new studies, Kelly and senior author Dipak Panigraphy wanted to understand how a diet supplemented with these fatty acids affects the anti-tumor activity of immune checkpoint blockade immunotherapy and anti-inflammatory therapy that inhibits the soluble enzyme epoxide hydrolase (sEH). Immunotherapy has been regulatory approved and is in clinical use while anti-inflammatory therapy is in clinical development.
The researchers used state-of-the-art mouse models of primary and metastatic tumors for the new study. They began feeding mice either a standard diet or a diet rich in omega-3 or 6 for 10 days before the tumor injection and for the duration of the study.
One week after tumor injection, the mice in each diet group were started with immunotherapy, anti-inflammatory therapy, both in combination, or no treatment.
The researchers found that dietary omega-3 fatty acid supplementation suppressed tumor growth in mice treated with immunotherapy, an sEH inhibitor, or both treatments used together . In contrast, mice on an omega-6-rich diet and treated with immunotherapy experienced faster tumor growth in certain tumor types.
In mice given the high omega-3 diet and both cancer treatments, up to 67% of tumor growth was inhibited compared with untreated and controlled mice. normal diet. This suggests that there may be synergistic anti-tumor activity, that is, the synergistic effect may be greater than the sum of its parts.
“For the first time, we have demonstrated that a combination of immunotherapy and anti-inflammatory therapy (sEHi) is more effective when mice are fed a diet rich in omega-3 fatty acids.” Kelly said. “This is very promising because dietary supplementation is easy to do for cancer patients and can be added to patients already receiving immunotherapy.”
Researchers are currently performing additional studies to determine the mechanism of action of the potentially synergistic anti-tumor activity induced by omega-3 supplementation.
They are conducting these studies with human cancer cells and tissues, human immune cells, and animal models to aid in translation of cancer patients. These new results by Kelly and colleagues may represent a new treatment approach that remains to be evaluated in humans.