Diabetes drug also kills cancer stem cells

BOSTON, Sept. 14 (UPI) -- U.S. scientists say they've found that in human breast cancer cell tumors in mice, a diabetes drug worked better than chemotherapy in prolonging remission.

Researchers led by Harvard Medical School Professor Kevin Struhl said the mice appeared tumor-free for two months after treatment before the end of the experiment. The drug, metformin, appears to selectively kill cancer stem cells in culture dishes and in mice.

The scientists said their findings provide additional rationale for testing metformin in combination with chemotherapy in people with breast cancer and perhaps other cancers.

The scientists said their findings add to a growing body of preliminary evidence in cells, mice, and people that metformin may improve breast cancer outcomes in people. In the new study, the diabetes drug seemed to work independently of its ability to improve insulin sensitivity and lower blood sugar and insulin levels, all of which are also associated with better breast cancer outcomes, the researchers said.

The study that included Heather Hirsch and Dimitrios Iliopoulos, along with Dr. Philip Tsichlis of Tufts University Medical Center, is reported in the early online edition of the journal Cancer Research.