The drug metformin, a mainstay of diabetes care for 15 years, may have a new life as a cancer treatment, researchers said.
In a study in mice, low doses of the drug, combined with a widely used chemotherapy called doxorubicin, shrank breast-cancer tumors and prevented their recurrence more effectively than chemotherapy alone.
The findings add to a growing body of evidence that metformin, marketed as Glucophage by Bristol-Myers Squibb Co. and available in generic versions, could be a potent antitumor medicine.
They also lend support to an emerging theory that cancer's ability to survive and resist therapy is regulated by cancer stem cells that drive a tumor's growth and survival.
Chemotherapy is effective against many tumors, said Kevin Struhl, a Harvard Medical School researcher and principal investigator of the study. "The problem is cancer stem cells acquire resistance" to treatment, he said. "They are able to regenerate the tumor and as a result you end up with a relapse."
About 5% to 10% of a tumor's cells are believed to be cancer stem cells, he said.
In the report, being published in the Oct. 1 edition of Cancer Research, a journal of the American Association for Cancer Research, researchers said the combination of metformin and doxorubicin killed both regular cancer cells and cancer stem cells.
In contrast, doxorubicin alone had limited effect on the stem cells.
Mice that grew tumors generated from human breast-cancer cells have remained tumor-free for nearly three months on the combined treatment, while tumors have recurred in those not given the diabetes remedy.
Sometimes it's good to lift your head out of the quagmire of people fucking up and finding that there are still some things going in the right direction.