Research Snapshot: Common Cancer Treatments Could Inadvertently Contribute to Recurrence

A new study published in the Journal of Experimental Medicine shows how chemotherapy, radiation and targeted therapy could be inadvertently contributing to the recurrence of some cancers.

While these frontline therapies work well at killing cancer, they often leave behind dead or dying cancer cells, creating inflammation in the tumor’s microenvironment. According to the study, this inflammation creates an ideal setting for any remaining living cancer cells to flourish, often leading to a recurrence of the disease or possibly a secondary form of cancer. The study also pointed to a potential solution known as resolvins – a class of Omega 3-derived lipids.

Researchers analyzed multiple types of cancer cells, including lung and pancreas cancer and T-cell lymphoma. They implanted a small amount of living cancer cells in a mouse and observed. While alone, these living cancer cells did not grow. However, when researchers added dead and dying cells – what you might expect after killing a tumor – the tumor growth skyrocketed.

Researchers then hypothesized if they could jump-start the body’s natural inflammation-reducing response, it would clear out the dead and dying cells that appear to promote the recurrence of cancer.

To do this, they injected resolvins into an animal model. That prompted macrophages, which are a special type of blood cell, to consume the dead and dying cells responsible for the inflammation.

“Macrophages are like the Pac-Men of blood. During inflammation, they travel to tissues and consume dead cells,” said Molly Gilligan, a study author and second-year student at the University of Minnesota Medical School. “If we can stimulate macrophages, using resolvins, than we can get rid of the inflammation surrounding the tumor’s microenvironment.”

When the resolvin-induced macrophages cleared-out the dead and dying cancer cells, tumor growth and metastasis in the animal models were inhibited.

Looking ahead, members of the research team plan to explore whether resolvins work to reduce the recurrence of brain, colon and other cancers. They will also explore whether and to what extent other Omega-3 derivatives act like resolvins in reducing tumor inflammation.

“With more research, we might find that resolvins or other similar lipids could serve as an adjunctive therapy to chemotherapy, radiation and targeted therapies,” said Megan Sulciner, first author on the study and third-year student at the University of Minnesota Medical School. “If Omega-3 derivatives are able to increase the effectiveness of our current treatments, this work could lead to a novel framework in the way we think about and treat cancer.”

The University of Minnesota Medical School students collaborated on this research with experts at Harvard Medical School, Beth Israel Deaconess Medical Center, Boston Children’s Hospital, the Dana Farber Cancer Institute, Brigham and Women’s Hospital, Institute of Systems Biology, Fred Hutchinson Cancer Research Center, London School of Medicine and Queen Mary University of London.