Scientists have found cancerous «fifth column» in the immune system of humans and mice

© Depositphotos / VtanovskiРаковые cellsScientists have found cancerous «fifth column» in the immune system of humans and mice© Depositphotos / Vtanovski

. The so-called neutrophils, one of the components of the immune system, can play the role of a «fifth column» and help the cancer to spread through the human body, interfering with the immunotherapy of a tumor and helping to isolate itself from the body, according to a paper published in the journal Cell Reports.

«Neutrophils play an important role in the fight against various pathogens, and therefore their removal from the body is unlikely to be carried out in hospitals in the treatment of cancer. We need to understand how they contribute to the development of lung cancer, which will help us to develop drugs that block the portion of neutrophils, which is responsible for the work of this «fifth column,» said Etienne Meylan (Meylan Ethienne) from the Federal Polytechnic school of Switzerland in Lausanne.

Today scientists believe that the immune system usually copes with the containment of primary tumors, the cells which are inside them. When cells acquire the ability to move yourself, there are metastases, which are the immune system for some reason just does not see and does not try to suppress the cancer cells. According to current statistics of the medical services of the United States, about 90% of deaths of cancer patients have metastases.

In recent years, scientists have discovered several mechanisms that allow cancer to evade the attention of the immune system and spread throughout the body. In some cases the cells cannot get inside certain immune Taurus and have them «deliver» themselves in other parts of the body, and in other cases they are «fake» is a kind of molecular passport of stem cells, posing as overgrown the wound.

Meilan and his colleagues discovered a kind of «fifth column» in the immune system that helps the cancer survive at all stages of its development, observing the growth of tumor cells, immune and the effects of chemotherapy, and experimental versions of immunotherapy, increasing the «aggressiveness» of T-cells and other parts of the immune system.

Grow several mice predisposed to the development of such forms of lung cancer, the researchers observed the development of tumors and tried to figure out which components of the immune system trying to destroy cancer, and which do nothing or even hinder the work of their comrades.

As shown by these observations, tumors developed faster in the body of those rodents who have been particularly active so-called neutrophils – special cells of the immune system that respond to inflammation and which is responsible for absorption and the «digestion» of bacteria and the production of specific set of substances, killing and repellent fungi and other microbes.

As it turned out, neutrophils are a kind of «fifth column» of cancer – until they accumulate at the boundaries of tumors, producing substances that repel the other immune cells and cause the blood vessels deliver less oxygen and nutrients to this part of the body. This leads to the mass destruction of healthy cells and creating a comfortable environment for cancer growth.

In addition, the lack of food causes cancerous cells to produce two protein signaling molecules, which attract the neutrophils, making it begins to grow even faster. This led the scientists to assume that the destruction of all or at least most part of neutrophils may slow or stop tumor growth.

Following this idea, biologists introduced into mice special antibodies that neutralize the «fifth column», and followed their fate. As it turned out, this therapy, despite its obvious negative effects, significantly extended the life of rodents and not only stopped the growth of tumors, but also reduced them to 42% in combination with immunotherapy.

Further study of these cells, as scientists hope, will help to understand how to get them to not «betray» the native body and create medicines that would help the person deal with the most aggressive forms of lung cancer and other malignant tumors.