A new discovery may lead to innovative approaches in cancer immunotherapy: A new study from Tel Aviv University found that white blood cells of the eosinophil type are recruited to fight healthy cancer metastases. According to the study, white blood cells secrete destructive proteins and at the same time recruit T cells of the immune system for a common fight against cancerous tumors. According to the researchers, their findings may contribute to the development of innovative approaches to the treatment of cancer immunotherapy based on the interaction between T cells and eosinophils.
The study was led by Prof. Ariel Munitz and doctoral student Sharon Grisero, from the Department of Microbiology and Clinical Immunology at the Sackler School of Medicine. The study was published in Cancer Research, a prestigious journal of the American Cancer Society.
The researchers explain that eosinophils are white blood cells of the immune system, which secrete destructively powerful proteins, whose function in evolution is to fight parasites. However, in the modern Western world, as parasites dwindle due to a high level of hygiene, eosinophils often become a negative factor, causing allergies and asthma.
However, the researchers believed that the ability of eosinophils to wreak havoc may in a sense become a positive factor that kills the “bad” cancer cells. Prof. Munitz explains: “We chose to focus on lung metastases for two main reasons: First, one of the main problems in the war on cancer is cancer metastases and not necessarily the primary tumor, and the lungs are a major target for metastases of many cancers. Second, in a preliminary study In mucous tissues like the lungs, so we thought they would also reach lung metastases. ”
In the first phase, the study examined human cancer tissues – biopsies of lung metastases taken from patients with metastatic breast cancer. The researchers found that eosinophils do reach the lungs, penetrate the cancerous tissues, and release the destructive substances they carry.
To examine the role of eosinophils in metastases, the researchers used an animal model and found that lung metastases that developed without eosinophils were much larger than those metastases attacked by eosinophils. These findings led to the conclusion that eosinophils are effectively fighting cancer, but the question still remains: how do they do it?
Prof. Munitz: “During the study we noticed that when there are no eosinophils in the tissue, T cells – white blood cells that are known to fight cancer are also absent.
To this end, the researchers conducted an extensive analysis to characterize the eosinophils found in metastases, and came up with two significant findings: first, eosinophils found in a cancerous environment release a large amount of substances called chemokines, which summon the T cells; And second, the chemokines are released in response to two other substances found in the cancer environment: IFN.g and TNF.α. That is, eosinophils exposed to IFN.g and TNF.α recruit T cells. In the last phase of the study, the researchers identified that it causes the development of metastatic T cells and a slowdown in the development of cancerous tumors.
Prof. Munitz: “Increasing the number and potency of T cells is one of the main goals of immunotherapy treatments given today to cancer patients. We have discovered a new interaction that mobilizes large numbers of T cells into cancerous tissues, and these findings may have therapeutic implications. Our research may form the basis for drug development. “Improved immunotherapies using eosinophils to eradicate cancer – on the one hand, eosinophils will release their destructive proteins against cancer, and on the other hand, they will increase the number of T cells in the cancerous environment. We speculate that the combined effect could significantly increase treatment effectiveness.”
The study was funded by the ICRF (Israeli Foundation for Cancer Research), the Association for the War on Cancer, ISF (National Foundation for Science), BSF (Binational Foundation for Science of the United States and Israel), and GSK.