Genetics has opened a new «signal of invulnerability» of cancer cells

© Depositphotos / VtanovskiРаковые cellsGenetics has opened a new «signal of invulnerability» of cancer cells© Depositphotos / Vtanovski

. Biologists from Stanford University found that cancer cells use not one but at least two signal molecules that tell the immune cells to ignore them, according to a paper published in the journal Nature Immunology.

«When in the human body appears cancer cells, their neighbors begin to develop the «SOS signals», which is usually read by macrophages, cells»cleaners» of the immune system. Some aggressive types of cancer produce a special signal «don’t eat me» CD47 protein molecules, which cause macrophages to ignore them. We opened another similar substance, the suppression of which causes the immune system to kill cancer cells,» says Irving Weissman (Irving Weissman) from Stanford University (USA).

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.

The experiments of the last two years show that this occurs for the reason that cancer cells can produce specific molecules that cause the immune system to believe that he was dealing with a healing wound or some other tissues, whose cells can divide.

Weissman and his colleagues had opened one such signal, watching as the macrophages interacted with the cultures of various cancer cells whose molecules CD47 was blocked with the help of special antibodies that prevent the immune cells to read these proteins.

Similarly, as explained by geneticist, and his team tested whether healthy and cancer cells, and other signals are «don’t eat me,» can make them «invisible» and «invulnerable» to the action of the immune system.

The suspicions of biologists justified – part of the cancer cells continued to remain «invisible» to macrophages, allowing them to multiply uncontrollably. Deciphering and comparing their genomes, scientists have discovered that the reason for this was that these cells have retained the genes responsible for the so-called «major histocompatibility complex» (MHC-I).

It is a kind of «passport», which immune cells are read by contact with other body tissues and which they can use in order to enable apoptosis, in other words, to get her to commit «suicide» in that case, if it has a virus or it is a part of the tumor.

As it turned out, the cancer cells can use a proper MHC-I as a kind of «Potemkin villages» that convinces the immune system that the cell is operating normally, although in reality it is not. When scientists deleted the gene for LILRB1 responsible for reading this «passport» with macrophages, the immune system began to fight the cancer in mice and successfully suppressed it. The same result can be achieved, suppressing the work of the B2m gene in the tumor itself.

The search for other genes «invulnerability» and methods of their suppression, as I hope the authors of the article, will help scientists to create a universal tool for the fight against cancer, and open methods of slowing its development, which will extend and save the lives of tens of millions of people throughout the world.