Common Diabetes Drug Shrinks Brain Tumors in Mice

Lisa Rapaport

November 03, 2021

Many cancers with known genetic causes can be treated by targeting tumors and leaving healthy cells unscathed. But that's not the case for a rare type of brain and spinal cord cancer that primarily strikes children and has no obvious genetic cause.

Preliminary testing in mice suggests that the diabetes drug metformin might target these tumors specifically. The drug acts on cell processes that drive the growth of posterior fossa group A (PFA) ependymomas.

This type of cancer is typically treated with surgery followed by radiation and chemotherapy. Chemotherapy attacks both tumors and normal tissue, so it often is linked to side effects such as swelling in the brain, hearing loss, seizures, and trouble with memory and speech.

When scientists gave metformin to mice with this cancer, tumor growth slowed and some tumors even shrank, according to results published in Science Translational Medicine. In some of the animals, metformin also lengthened survival.

In mice whose tumors showed initial resistance to metformin, scientists overcame the resistance by adding in panobinostat, an experimental brain cancer drug.

Other preliminary research in animals suggests that metformin may also be effective alone or with radiation to slow growth of prostate, breast, ovarian and skin malignancies. The findings are all in early stages because what seems to be effective in mice often fails when tested in people.  In fact, two clinical trials of metformin in patients with lung cancer have recently reported disappointing results.


American Society of Clinical Oncology, "Ependymoma — Childhood: Statistics."

American Cancer Society: "Radiation Therapy Side Effects."

Science Translational Medicine: "Targeting integrated epigenetic and metabolic pathways in lethal childhood PFA ependymomas."

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