Tumors, that’s why immune cells don’t fight them
When immune cells come into contact with cancer cells it can trigger a mechanism by which the body’s own defenses can weaken, which promotes the spread of cancer. Scientists from Ottawa Hospital and the University of Ottawa, who published an article in the journal Science Advances to announce the results of their work, describe this particular phenomenon in unprecedented detail.
The research group, led by Michele Ardolino, has discovered the dynamics that guide the process for which immune cells fall asleep and lose effectiveness in their antitumor action. When natural immune cells, known as Natural Killer (NK), get close enough to another biological unit, a known phenomenon called trogocytosis, a kind of ‘kiss’ between cellswhich leads the NKs to take a fragment of cell membrane from their antagonists.
Researchers have discovered that this process can trigger the release of the PD-1 protein, capable of acting on the activity of immune cells by decreasing their antitumor capacity. “NK cells – says Ardolino, senior scientist at the Ottawa hospital and assistant professor at the University of Ottawa – are exceptional cancer killers.
Previous work has shown that PD-1 protein can prevent immune cells from functioning properly. Until now, however, we did not know how NKs could be exposed to the protein. Now we have discovered that this derives directly from cancer cells “.” We still have to understand why NK removes the membranes from cancer cells – adds the expert – but it seems clear that Cancers can hijack the process to evade the immune system“.
The scholars specify that drugs able to counteract PD-1, also called immune checkpoint inhibitors, are already used for the treatment aimed at reactivating T lymphocytes. These drugs, administered to various cancer patients, have significantly improved the survival of people with certain types of skin, blood and lung cancers. “A better understanding of how these drugs can act on different types of immune cells – concludes Ardolino – could lead to new types of immunotherapy and cancer treatments”.