Anti-diabetes drug effective against cancer

A new study is providing even more evidence that a widely-used anti-diabetes drug may also be effective in fighting breast cancer. The new study from Harvard Medical School found that combining metformin, sold as Glucophage, with the chemotherapy drug doxorubicin, reduced breast cancer tumours faster than doxorubicin alone, when tested on mice.

What’s more, the drug combo also prolonged remission in the mice longer than chemotherapy alone.

The researchers, writing in the journal Cancer Research, say the metformin combo seems to work by targeting the cancer’s stem cells and may improve breast cancer outcomes in people.

Evidence is growing that part of the reason why many cancers recur is that current treatments do not target a cancer’s stem cells, which can resist chemotherapy and regenerate the various cell types in a tumour. So some researchers have been investigating therapies that selectively target cancer stem cells.

Now, researchers think they’ve found one that shows promise.

“We have found a compound selective for cancer stem cells,” said senior author Kevin Struhl, a professor of biological chemistry and molecular pharmacology at Harvard Medical School. “What’s different is that ours is a first-line diabetes drug.”

Metformin is a medication widely used to treat type 2 diabetes and is especially effective in obese diabetics who overproduce insulin. It works by preventing the liver from breaking down starch into sugar while also stimulating uptake of sugar by the body’s muscles, causing blood sugar and insulin levels to fall.

But the drug has also been found to reduce cancer risk. A number of studies have found that diabetic patients who take metformin have a significantly lower cancer rate, with those taking the highest doses for the longest period of time having the lowest rates.