A Brazilian berry may hold the key to cancer treatment

Polyphenols are “organic compounds found abundantly in plants, [which] have become an emerging field of interest in nutrition in recent decades.”

A recent review notes “A growing body of research indicates that polyphenol consumption may play a vital role in health through the regulation of metabolism, weight, chronic disease, and cell proliferation.”

Canadian researchers have discovered that a polyphenol from the Brazilian camu-camu berry, castalagin, helps increase the efficacy of immunotherapy in mice by modifying their microbiome.

“Oral supplementation with the polyphenol-rich berry camu-camu (CC, Myrciaria dubia) in mice,” write the researchers, “shifted gut microbial composition, which translated into antitumor activity and a stronger anti-PD-1 response.” Programmed cell death protein 1 (PD-1) is “an inhibitory receptor that is expressed by all T cells during activation. It regulates T cell effector functions during various physiological responses, including acute and chronic infection, cancer and autoimmunity, and in immune homeostasis.”

To put it simply: the Amazonian fruit camu-camu can help fight cancers. Researchers writing in Cancer Discovery journal under the leadership of Dr Bertrand Routy, a professor in Universite de Montreal’s Department of Medicine, point out that a compound from camu-camu can affect immunotherapy positively.

“With this research, conducted with our colleagues from Universite Laval and McGill University, we have proved that castalagin, a polyphenol acting as a prebiotic, modifies the gut microbiome and improves immunotherapy response, even for cancers resistant to this type of treatment,” says Routy. 

“Our results pave the way for clinical trials that will use castalagin as a complement to medications called immune checkpoint inhibitors in cancer patients,” adds Meriem Messaoudene, a postdoctoral student in Routy’s lab and first author of the study.

Immune checkpoint inhibitors (ICI) “have emerged [in the past decade] as anticancer agents able to modify, for the better, the natural history of a wide range of malignancies, such as melanoma, renal cell carcinoma, non-small cell lung cancer (NSCLC), bladder cancers, Hodgkin lymphoma and others.”

While patients are heartened by ICI, which activates the immune system to kill cancer cells, only a minority of patients have long lasting responses to immunotherapy “akin to a cure” the news release informs.

Researchers such as Routy are seeking new therapies, hoping to convert an unhealthy microbiome into a healthy one to strengthen the immune system.

One of the ideas Routy has had involves prebiotics, which “can feed the intestinal microbiota, and their degradation products are short-chain fatty acids that are released into blood circulation, consequently, affecting not only the gastrointestinal tracts but also other distant organs.”

“To evaluate the beneficial effects of castalagin, we orally administered the prebiotic to mice that had received a fecal transplant from patients resistant to ICI,” he says. “We found that castalagin binds to a beneficial intestinal bacteria, Ruminococcus bromii, and promotes an anti-cancer response.”

The researchers’ discovery will be tested on 45 individuals soon who are afflicted with lung cancer or melanoma. This will be the first clinical trial combining the polyphenol from the Brazilian camu-camu berry, castalagin, and ICIs.

“Up to $1 million in funding over three years is being provided by the Weston Family Foundation as part of its Brain Health 2021: Lifestyle Approaches and Microbiome Contributions program,” the news release notes.