Summary: Vitamin D strengthens a type of gut bacteria in mice, improving their immunity against cancer. The study shows that mice with higher levels of vitamin D resist tumor growth better and respond more effectively to immunotherapy.
This effect appears to be linked to the increase in Bacteroides fragilis in the gut, which somehow boosts the mice’s immune response against cancer. Further research is needed to see if this applies to humans, as previous studies suggest a potential link between vitamin D levels and cancer risk.
Highlights:
- Role of vitamin D: Mice fed vitamin D had increased levels of Bacteroides fragilis, which helped them resist cancer better.
- Human implications: Analysis of preliminary data from 1.5 million people in Denmark suggests a correlation between low vitamin D levels and a higher risk of cancer.
- Future research: Understanding how vitamin D can be used to boost the beneficial gut microbiome could open new avenues for cancer treatment and prevention.
Source: Francis Crick Institute
Researchers from the Francis Crick Institute, the National Cancer Institute (NCI) of the US National Institutes of Health (NIH) and Aalborg University in Denmark have discovered that vitamin D promotes the growth of a type of intestinal bacteria in mice, which improves immunity against cancer.
Reported today in ScienceResearchers found that mice fed a vitamin D-rich diet had better immune resistance to experimentally transplanted cancers and better responses to immunotherapy treatment.
This effect was also seen when gene editing was used to remove a protein that binds to vitamin D in the blood and keeps it away from tissues.
Surprisingly, the team discovered that vitamin D acts on epithelial cells in the intestine, increasing the amount of a bacteria called Bacteroides fragilis. This microbe gave the mice better immunity to cancer because the transplanted tumors didn’t grow as much, but researchers don’t yet know how.
To test whether the bacteria alone could confer better immunity against cancer, mice on a normal diet were given Bacteroides fragilis. These mice were also better able to resist tumor growth, but not when put on a vitamin D-deficient diet.
Previous studies have proposed a link between vitamin D deficiency and cancer risk in humans, although the evidence has not been conclusive.
To study this, researchers analyzed a dataset from 1.5 million people in Denmark, which found a link between lower vitamin D levels and a higher risk of cancer.
A separate analysis of a cancer patient population also suggested that people with higher vitamin D levels were more likely to respond well to immune-based cancer treatments.
Although Bacteroides fragilis is also found in the microbiome in humans, further research is needed to understand whether vitamin D helps provide some immune resistance to cancer through the same mechanism.
Caetano Reis e Sousa, head of the Crick’s immunobiology laboratory and lead author, said: “What we showed here was a surprise: vitamin D can regulate the gut microbiome to favor a type of bacteria that gives mice better immunity. to cancer.
“This may one day be important for the treatment of cancer in humans, but we do not know how and why vitamin D exerts this effect via the microbiome. Further work is needed before it can be conclusively stated that correcting vitamin D deficiency has benefits for cancer prevention or treatment.
Evangelos Giampazolias, former postdoctoral researcher at Crick and now head of the Cancer Immunosurveillance Group at Cancer Research UK Manchester Institute, said: “Identifying the factors that distinguish a ‘good’ from a ‘bad’ microbiome is a major challenge. We found that vitamin D helps gut bacteria develop immunity against cancer, thereby improving the response to immunotherapy in mice.
“A key question we are currently trying to answer is how exactly vitamin D supports a ‘good’ microbiome. If we can answer this question, we could discover new ways in which the microbiome influences the immune system, potentially offering exciting possibilities in the prevention or treatment of cancer.
Romina Goldszmid, Stadtman Researcher at the NCI Center for Cancer Research, said: “These findings contribute to the growing body of knowledge on the role of the microbiota in cancer immunity and the potential for dietary interventions to refine this relationship to to improve patient outcomes.
“However, further research is needed to fully understand the underlying mechanisms and how they can be exploited to develop personalized treatment strategies. »
This research was funded by Cancer Research UK, the UK Medical Research Council, the Wellcome Trust, an ERC Advanced Investigator grant, a Wellcome Investigator Award, a Fondation Louis-Jeantet award, the NCI Intramural Research Program, which is part of the National Institutes of Health, JRC-NCI and Danish National Research Foundation.
Dr Nisharnthi Duggan, head of research information at Cancer Research UK, said: “We know that vitamin D deficiency can cause health problems, however, there is not enough evidence to link vitamin D levels to cancer risk.
This early-stage research in mice, combined with an analysis of data from the Danish population, aims to fill the evidence gap. Although the results suggest a possible link between vitamin D and immune responses to cancer, more research is needed to confirm it.
“A little sunshine can help our bodies produce vitamin D, but sunbathing is not necessary to stimulate this process. Most French people can produce enough vitamin D by spending short periods in the sun in summer.
“We can also get vitamin D through our diet and supplements. We know that staying safe in the sun can reduce the risk of cancer, so be sure to seek shade, cover up and apply sunscreen when the sun is strong.
About this cancer and microbiome research news
Author: Claire Green
Source: Francis Crick Institute
Contact: Clare Green – Francis Crick Institute
Picture: Image is credited to Neuroscience News
Original research: Closed access.
“Vitamin D regulates microbiome-dependent cancer immunity” by Caetano Reis e Sousa et al. Science
Abstract
Vitamin D regulates microbiome-dependent cancer immunity
A role for vitamin D in immune modulation and cancer has been suggested. In this work, we report that mice with increased vitamin D availability exhibit greater immunodependent resistance to transplantable cancers and increased responses to checkpoint blockade immunotherapies.
Similarly, in humans, vitamin D-induced genes correlate with improved response to immune checkpoint inhibitor therapy as well as increased cancer immunity and overall survival.
In mice, resistance is attributable to the activity of vitamin D on intestinal epithelial cells, which modifies the composition of the microbiome in favor of Bacteroides fragiliswhich positively regulates immunity against cancer.
Our results indicate a previously unrecognized link between vitamin D, microbial commensal communities, and immune responses to cancer.
Collectively, they highlight vitamin D levels as a potential determinant of cancer immunity and immunotherapy success.
News Source : neurosciencenews.com
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