Knowing which gut bacteria are linked to helping the immune system, could lead to improved cancer treatments
Researchers from the University Of Calgary, Canada, have discovered which gut bacteria are responsible for helping the immune system battle cancerous tumours and how they do it. Their findings may improve understanding of why immunotherapy works in some instances but not others.
Publishing their research in Science the researchers show that combining immunotherapy with specific microbial therapy boosts the ability of the immune system to recognise and attack cancer in some melanoma, bladder and colorectal cancers. Research studies have provided strong evidence that gut microbiota can positively affect anti-tumour
The research team identified bacterial species that were associated with colorectal cancer tumours when treated with immunotherapy. Using germ free mice, they then introduced these specific bacteria along with a type of cancer immunotherapy called immune checkpoint inhibitor. It was found that specific bacteria were essential for the immunotherapy to work, with the tumours shrinking significantly. For those not treated with the beneficial bacteria the immunotherapy had no effect.
Dr Lukas Mager MD, PhD, senior postdoctoral researcher at the University of Calgary and first author of the study said ‘We found that these bacteria produce a small molecule called inosine. This interacts directly with T-cells, and together with immunotherapy, it improve the effectiveness of that treatment in some cases destroying all the colorectal cancer cells.’
The findings have been validated in both bladder cancer and melanoma. The next step for the research team is to study the findings in humans.
Dr Cathy McCoy, Professor at the Cummings School of Medicine’s Department of Physiology & Pharmacology said ‘Identifying how microbes improve immunotherapy is crucial to designing therapies with anti-cancer properties, which may include microbials. The microbiome is an amazing collection of billions of bacteria that live within and around us. We are in the early stage of fully understanding how we can use this new knowledge to improve efficacy and safety of anti-cancer therapy and improve cancer patient survival and wellbeing.’