Metformin is a commonly prescribed drug for the treatment of type 2 diabetes. While clinical studies have indicated that metformin also has a role in the prevention of cancer the mechanism has not been known until now. Shingo Eikawa and Mikako Nishida from the Okayama University Graduate School of Medicine in Japan and colleagues have discovered why metformin helps prevent cancer. The research was published in the edition of the journal Proceedings of the National Academy of Sciences.
The researchers compared the effect of metformin on two groups of mice. One group of mice was genetically modified to have fewer functioning T-cells. The mice that were normal showed an increased ability to reject solid tumors. The increased ability to reject tumor growth was the result of an increased number of tumor-infiltrating lymphocytes. The tumor-infiltrating lymphocytes induced by metformin did not suffer as rapid a death as is normal in cancer and were capable of killing solid cancer cells for longer periods of time.
The immune-mediated response was suspected and now has been proven. The researchers also found that metformin accelerated the migration of cancer fighting cells into solid cancers. Metformin overrides the natural death process of cancer fighting cells that normally occur in active cancer.
The researchers suggest two potential uses of this discovery. A person with cancer could be given metformin and additional drugs to keep the patient’s blood sugar levels at normal values. A drug that has the same cancer fighting effect may be developed that shows the same effect as metformin now that the pathway that metformin improves cellular cancer fighting capacity is known.
