COVID-19 caused mice to experience shrinking cancer cells, early data shows

A recent study published in the Journal of Clinical Investigation has revealed a surprising potential benefit of severe COVID-19 infections: the ability to shrink cancer tumors. This groundbreaking discovery, based on research conducted in mice, has opened new doors for cancer treatment by highlighting intricate interactions between the immune system and cancer cells. 

The immune system plays a crucial role in the body’s defense against diseases, including cancer. Many modern cancer therapies focus on harnessing the immune system’s power to target malignant cells. This study focuses on monocytes, a type of white blood cell integral to immune defense. The Live Science publication has highlighted the excited findings, noting, that monocytes typically protect the body from infections, but can sometimes be subverted by tumors in cancer patients, transforming into cells that shield cancer from immune attacks.

The researchers discovered that severe COVID-19 infections can trigger the production of a unique type of monocyte with potent anti-cancer properties. These “induced” monocytes are specifically adapted to combat the COVID-19 virus but also retain the capacity to attack cancer cells effectively.

Mechanism Behind Induced Monocytes

The key to this discovery lies in the genetic material of the COVID-19 virus. These induced monocytes possess a specialized receptor that binds precisely to a specific sequence of COVID RNA. Ankit Bharat, a lead scientist from Northwestern University, described the interaction as a “lock-and-key” relationship, with the COVID RNA serving as the perfect fit for the monocyte receptor.

This unique mechanism was tested through experiments involving mice with advanced stage 4 cancers, including melanoma, lung, breast, and colon cancers. The mice were administered a drug that simulated the immune response to severe COVID-19, prompting the production of these special monocytes. The results were striking: tumors across all four types of cancer began to shrink.

Unlike regular monocytes, which can be hijacked by tumors to become protective agents for cancer, these induced monocytes retained their anti-cancer functionality. They successfully migrated to tumor sites—a task most immune cells struggle with—and activated natural killer cells. These killer cells then launched direct attacks on the cancer cells, resulting in tumor shrinkage.

A Breakthrough Beyond T Cells

This discovery presents a new avenue for cancer treatment that operates independently of T cells, which are the cornerstone of many existing immunotherapies. While immunotherapy has shown promise in treating cancer, its effectiveness is limited to about 20–40% of cases. Often, these therapies fail because the patient’s body cannot produce enough functional T cells.

The newly identified mechanism offers an alternative by bypassing the reliance on T cells and directly targeting tumors through induced monocytes. This could provide a lifeline for patients who do not respond to traditional immunotherapy.

While this research is still in its early stages and has so far only been conducted on mice, its implications are profound. The findings suggest the potential for developing new drugs or vaccines that can stimulate the production of these cancer-fighting monocytes in humans. Notably, COVID-19 vaccines are unlikely to trigger this mechanism because they do not contain the full RNA sequence of the virus. Nevertheless, the study opens up exciting possibilities for future cancer therapies.

Broader potential of "Trained Immunity"

The implications of this research extend beyond cancer and COVID-19. It highlights the concept of “trained immunity,” where the immune system is conditioned by one threat to become more effective against another. This area of research could lead to innovative treatments for a wide range of diseases by leveraging the immune system’s adaptability.

This study offers a glimpse into the untapped potential of the immune system in combating cancer. By uncovering how severe COVID-19 infections can trigger the production of unique, cancer-fighting monocytes, researchers have identified a promising new path for cancer treatment.

While it is important to emphasize that this does not suggest people should seek to contract COVID-19 for potential health benefits and clinical trials in humans are necessary to confirm these findings, the research underscores the remarkable adaptability of the immune system and its potential to transform cancer therapy.

By Nazrin Sadigova