A new natural defense mechanism against cancer has been discovered

Immune cells are capable of "transferring" special DNA fragments to each other and to tumors, enhancing their ability to recognize and destroy cancer. This is the conclusion reached by researchers from Weill Cornell Medical Center. The discovery is described in an article in the journal Cancer Cell.

Scientists discovered that activated T cells - key participants in the immune response - release extracellular vesicles. These are microscopic membrane "capsules" that cells use to transmit signals. Inside these vesicles are DNA fragments capable of penetrating other cells.

Experiments showed that these DNA-containing vesicles are taken up by both other immune cells and tumor cells themselves. Once inside, they enhance the process of antigen presentation - the mechanism by which the immune system recognizes threats. As a result, tumors become "visible" to the immune system, which begins to attack them more actively.

Normally, cancer cells attempt to hide from immune surveillance by suppressing this process. However, the discovered mechanism effectively reverses the situation: the vesicles restore the immune system's ability to recognize the tumor.

In preclinical animal experiments, the administration of such vesicles led to slowed tumor growth and enhanced infiltration of immune cells into the tumors. The effect was observed in several types of cancer, including glioblastoma, pancreatic cancer, and triple-negative breast cancer - forms that typically respond poorly to immunotherapy.

The researchers also found that the DNA within the vesicles is not random: it is enriched with genes associated with immune function. Additionally, an enzyme is present on the surface of the vesicles that helps deliver this genetic material directly into the cell nucleus, where it can be temporarily activated.

According to the authors, the discovery points to the existence of a natural "amplification loop" in the immune response: T cells not only attack the tumor directly but also enhance the functioning of the entire immune system through the transfer of genetic signals.

The team is currently working on developing new therapeutic approaches based on this mechanism. It is anticipated that such vesicles could be used as a standalone treatment or in combination with existing immunotherapy methods.