Diabetes drug immune boost 'may improve anti-cancer vaccines'
US scientists have discovered that a common diabetes drug can boost the function of the immune system's 'memory' in mice. They speculate that this may help to make vaccines - including experimental 'cancer vaccines' - more effective in humans, although their research, published in Nature, looked at the drug's effect on mice.
Researchers at McGill University and the University of Pennsylvania were investigating how the body produces specialised white blood cells called 'memory' T-cells, which form an important part of the human immune system.
Memory T-cells 'remember' infections that the body has encountered - including those contained in vaccines - and allow the body to respond to subsequent infections more quickly.
The team previously studied how molecules called fatty acids are involved in transforming normal T-cells into memory T-cells after an infection.
To investigate this further, they looked at a type of mouse that carried a gene defect that meant that, while it responded normally to infection, it couldn't generate memory T-cells afterwards.
Metformin, a drug used to treat diabetes, is known to be able to affect the way fatty acids are broken down by the body.
When they gave metformin to the memory-cell-deficient mice, it jump-started their ability to make memory T-cells.
Testing metformin on normal mice, the team found that it boosted their ability to generate memory T-cells and caused them to respond better to an experimental cancer vaccine.
Cancer vaccines are experimental treatments that aim to encourage a patient's immune system to attack their cancer. Several laboratories around the world are developing them, but none are yet in routine clinical use.
Dr Erika Pearce, from the University of Pennsylvania, revealed: "We used metformin, which is known to operate on fatty acid metabolism, to enhance this process and have shown experimentally in mice that metformin increases T-cell memory as well as the ensuing protective immunity of an experimental anti-cancer vaccine."
Co-author Dr Yongwon Choi, professor of pathology and laboratory medicine at the University of Pennsylvania School of Medicine, added: "Our findings were unanticipated, but are potentially extremely important."
Dr Kat Arney, Cancer Research UK's senior science information officer, commented: "This is a fascinating piece of research. At the moment, this research has only been done in mice and there is a long way to go before it can be applied to cancer patients, but it certainly holds promise for the future."
Pearce, E., Walsh, M., Cejas, P., Harms, G., Shen, H., Wang, L., Jones, R., & Choi, Y. (2009). Enhancing CD8 T-cell memory by modulating fatty acid metabolism Nature DOI: 10.1038/nature08097