Gut microbiota, allies in the fight against cancer

A surveyor and trailblazer who journeys into little-explored scientific realms, Meriem Messaoudene is a traveller at heart with a passion for geography that has taken her from one continent to another. As she made her way on her travels, she has gleaned wisdom here and there and has been able to rely on a few compasses—of the human type.

To travel far, you need to be prepared as best as possible. This postdoctoral fellow readied herself by learning from the world’s leading immuno-oncology experts such as Dr. Laurence Zitvogel. Having completed a bachelor’s degree in immunology and biochemistry in Algeria, the young woman took a road less travelled and went to Paris, France. There, she completed her master’s degree and PhD before joining Dr. Zitvogel at the Gustave Roussy Institute of Oncology.

“Laurence is still a true mentor for me. I was lucky to do my first postdoctoral fellowship under her supervision. She’s passionate about her work on gut microbiota and cancer, for which she has received international recognition,” she explained.

While with the team in Paris, she met a young doctor and researcher, Dr. Bertrand Routy. Together, they would go on to establish the immunotherapy and oncomicrobiome laboratory at the CHUM Research Centre.

Awakening the immune system 

In 2018, thanks to a publication in Science, the saga of these two scientists got off to a bright start. At the time, they showed that gut microbiota, which harbours billions of bacteria, influenced the efficacy of immunotherapy treatments, which awakened the immune system so that it could fight off cancer.

“From the outset, we wanted to develop that research theme and go further to improve the treatments offered to patients, their survival and their quality of life.”

In January 2018, full of ambitious energy, she and Dr. Routy launched their laboratory on the 12th floor of the Research Centre.

Today, 12 people make up the team that aims is to transform a “bad” microbiome into a healthy one to thwart cancer’s plans. Several approaches are possible: reducing the dysbiosis caused by antibiotics, playing with diet and offering prebiotics or probiotics to increase the efficacy of the immunotherapy.

A berry from brazil as backup  

For a year, their team has even been trying to determine whether a fecal transplant modifying gut microbiota could increase the efficacy of immunotherapy targeting metastatic melanoma or non-small-cell lung cancer. Their objective is to increase the life expectancy of cancer patients.

It’s a first in Canada that will make it possible to identify “good” bacteria to increase the efficacy of immunotherapy.

 Simultaneously, in early 2022, we also showed for the first time in mice that castalagin, a polyphenol from the Amazonian camu camu berry, acts as a prebiotic, modifies the gut microbiome and improves the response to immunotherapy. 

The Amazonian fruit was already known for its protective effects against obesity and diabetes. It is now known for its anti-cancer benefits, even for immunotherapy-resistant cancers. At least on an animal model.

These promising results pave the way for clinical trials that will use castalagin to complement drugs called immune checkpoint inhibitors in cancer patients.

From peak to peak

Meriem Messaoudene sees herself working a few more years at the Research Centre—long enough to see the results of her research implemented in clinical settings.

“I believe that we would not have made such swift progress if we had not been supported from the outset by the CRCHUM, whether by management or by the people working in the core facilities. In this regard, the exceptional expertise of the animal facility staff allowed us to establish germ-free mice essential for the continuation of our projects.”

In June, the researcher went to Vienna to present her work to the Seerave Foundation, a philanthropic organization that will provide funding for two years so that she can continue her research on castalagin to better understand its impact on bacteria.

Even though she is still as passionate as ever about her research projects, travelling for pleasure is still important to her. She is planning to scale Mt. Kilimanjaro in Africa in the near future. “Life is short,” she reminds us.