The December 2016 issue of Science Advances reported that combining the antidiabetic drug metformin with the antihypertensive medication syrosingopine has shown effectiveness against several types of cancer.
The use of metformin has been associated with protection against cancer as well as therapeutic benefits, however, doses used to treat diabetes are too low for optimal anticancer effects. The current research found that syrosingopine sensitized cultured cancer cells to metformin and phenformin at a dose that was significantly lower than the individual toxic threshold of either compound. "For example, in samples from leukemia patients, we demonstrated that almost all tumor cells were killed by this cocktail and at doses that are actually not toxic to normal cells,” stated first author Don Benjamin of the Biozentrum of the University of Basel. "And the effect was exclusively confined to cancer cells, as the blood cells from healthy donors were insensitive to the treatment."
The researchers, led by Professor Michael N. Hall, also of Biozentrum, found that the drug combo induced programmed cell death in promyelocytic leukemia and multiple myeloma cells. In mice with liver cancer, enlargement of the organ was reduced and the number and size of tumor nodules was decreased in association with treatment with the two drugs compared to the control animals. Two of the mice had livers that were tumor free.
While metformin reduces blood glucose and blocks the mitochondria’s respiratory chain, syrosingopine inhibits the degradation of sugars, thereby interfering with processes that provide energy to the cells. "We have been able to show that the two known drugs lead to more profound effects on cancer cell proliferation than each drug alone," Dr Benjamin concluded. "The data from this study support the development of combination approaches for the treatment of cancer patients."