Cancer breakthrough at the Montreal Clinical Research Institute

Research conducted in Montreal could one day offer doctors a new weapon when it comes to activating the immune system against cancer.

Dr. André Veillette’s team at the Montreal Clinical Research Institute has identified a molecule whose inactivation allows components of the immune system, macrophages, to recognize and attack cancer cells.

Laboratory experiments then made it possible to eliminate leukemia and lymphoma-type cancers in mouse models.

Cancer cells, explained Dr. Veillette, have the ability to “put to sleep” the immune system, which then allows them to proliferate as they please.

However, it is possible to circumvent this problem by administering to the patient what scientists call “checkpoint inhibitors” to allow the immune system to do its job.

“Macrophages are cells that have the ability to devour whole cancer cells and destroy them,” he said. “There have been some successes with agents that targeted another molecule, (…) but we wanted to identify others because the successes with these treatments were not universal for all cancers.”

The field of immunotherapy is booming and has generated some of the most promising breakthroughs in the fight against cancer over the past decade.
This work, carried out by student Jiaxin Li, is, however, among the first to successfully mobilize macrophages in the fight against cancer. Other breakthroughs in immunotherapy have focused mainly on other components of the immune system, T lymphocytes.

The new study, the authors emphasize, therefore demonstrates “the crucial need to continue research on the mechanisms that regulate immune cell functions, in order to better exploit them to develop effective and safer therapeutic strategies against human diseases.” Dr. Veillette’s team found that blocking the CD200R1 molecule, which is expressed on the surface of cancer cells, with antibodies allows macrophages to detect and attack them.

“We identified CD200R1 as an immune checkpoint that suppresses the ability of macrophages to do (their job),” he said. “Then we demonstrated that when we blocked this with antibodies, we increased the ability of macrophages to eliminate cancer cells in petri dishes or in mouse models.”

The researchers are now continuing their work to identify even more effective antibodies against CD200R1, although the effectiveness of those currently available is “clear.”

Now, they remain hopeful that preclinical successes will translate to humans.

“We’ve been working on this for ten years,” concluded Dr. Veillette. “It wasn’t easy, especially during the pandemic, but the student persisted. I really hope it will lead to something.”

The findings of this study were published in Nature Communications.

–This report by La Presse Canadienne was translated by CityNews