Colon cancer: A new ally discovered to fight metastases.

A new "ally" has been identified to combat colorectal cancer metastases. In a study conducted at Sapienza University of Rome, a group of researchers demonstrated the key role of the alliance between macrophages and natural killer cells in countering the growth of metastases. The results, published in the Journal of Clinical Investigation, pave the way for new therapies for this tumor. Colorectal cancer is the second leading cause of cancer death worldwide. Although it has become much more curable in recent years, treatments are still not effective in all patients. The continuing high mortality rate for this type of cancer is primarily due to its ability to spread to other parts of the body, causing metastases in a significant fraction of patients. In this context, natural killer (NK) cells, the researchers explain, are a type of white blood cell belonging to the innate immune system that can help counteract the spread of the tumor. Their name derives from their ability to recognize and spontaneously destroy tumor cells and inhibit the formation of metastases. Despite this, the behavior of natural killer cells in already formed metastases, particularly in the liver, remains unclear. In the study, supported by the AIRC Foundation for Cancer Research, immunologist Giovanni Bernardini and colleagues investigated the specific role of NK cells in the metastatic environment to understand how to better protect and preserve their anti-tumor capabilities. Coordinated by the Department of Molecular Medicine at Sapienza University, the research was conducted in collaboration with several national and international groups. The results revealed a natural defense mechanism that can help slow the growth of liver metastases. Specifically, the researchers demonstrated that not all liver metastases are the same. Some types form microenvironments in which NK cell activity is enhanced thanks to the presence of molecules capable of promoting the persistence of these cells and their ability to attack the tumor. These are a specific type of macrophage, the so-called "scavengers" of the immune system, capable of teaching natural killer cells how to properly activate and attack tumor cells. Overall, the published data demonstrate that proper cooperation between macrophages and natural killer cells is essential for activating an immune response capable of limiting the spread of colorectal cancer, opening up new therapeutic perspectives based on strengthening this network.