Major work led by Dr. André Veillette’s team at the Institut de recherches cliniques de Montréal (IRCM), in collaboration with a group of researchers, and just published in Nature Immunology , managed to identify a previously unknown way which prevents phagocytosis, which is a process that promotes the immune system’s response to cancer.
Macrophages are cells of the immune system. One of the roles of macrophages is to engulf, or ’eat’, cells that are defective or dangerous, including cancer cells. This process is named phagocytosis. Macrophages can be called into action to eliminate cancer cells. However, this capacity is often defective, because macrophages are put in a state of dormancy by the cancer cells. This is in part because a particular molecule called CD47 is often over-abundant on cancer cells. CD47 prevents phagocytosis by triggering a molecule or "receptor"on macrophages named SIRP’. Agents that block the ability of CD47 to trigger SIRP? have shown promising results for treating cancer.
The research team collaborated in the identification of a previously unknown way by which CD47 prevents phagocytosis. They found that CD47 also blocks the molecule SLAMF7 on blood cancer cells, such as multiple myeloma and lymphoma. The researchers developed a new antibody, named Z10, that frees SLAMF7 from CD47, thereby augmenting elimination of tumor cells. When combined with other agents Z10 is highly effective against cancer cells expressing SLAMF7, at least in mice.
Why this research mattersCancer remains the leading cause of death in Canada. It is estimated that two out of five Canadians will be diagnosed with cancer in their lifetime, and approximately one in four will die from the disease. The battle against cancer is thus still raging on several fronts, and the deep understanding of the role of the immune system in the growth of cancer cells is a major component of this battle.
These data suggest that Z10 is an effective new treatment for human cancers expressing SLAMF7, including multiple myeloma and lymphoma. The Veillette team is now setting up partnerships with pharmaceutical companies to test Z10 in clinical trials.
This study was done in collaboration with the laboratory of Enfu Hui, an expert in protein-protein interactions and immune regulation.