Sometimes a drug intended for one purpose turns out to have other uses.
Metformin, a treatment for type 2 diabetes, may prove effective in treating cancer.
Researchers are a step closer to figuring out how metformin may help prevent cancer.
Metformin is generally used to treat type 2 diabetes. The drug helps the
body use insulin more effectively.
It also helps lower glucose production in the liver. And it’s relatively
Observational studies have suggested that people who take it may have a
lower risk of certain types of cancer.
Researchers at the University of California, San Diego, wanted to know
why. The answer could lead to better prevention and more effective cancer
Details of their research are published in the journal
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What the research says
All cells possess cell polarity. It’s what allows them to perform
Polarity lets epithelial cells form protective walls in cavities and organs.
The walls protect against toxins, pathogens, and inflammatory triggers.
Any crack in the wall can open the door to cancer.
The research team identified the mechanism that helps keep the wall strong.
Researchers already knew about something called the stress-polarity pathway.
As stated in the researchers’
press release, it’s “a specialized pathway mobilized only during periods
of stress. It is orchestrated by a protein kinase called AMPK that protects
cellular polarity when epithelial cells are under energetic stress and
an activator of AMPK called LBK1.”
LBK1 is a tumor suppressor. LBK1 mutations are associated with loss of
cell polarity and cancer.
The mystery was in how the LKB1-AMPK pathway preserves cell polarity during stress.
The new research found that the stress-polarity pathway relies on a protein
called GIV/Girdin. Metformin affects this protein.
"In summary, by identifying GIV/Girdin as a key layer within the stress-polarity
pathway we've peeled another layer of the proverbial onion,"
Dr. Pradipta Ghosh, the study’s senior author, said in the press release.
Ghosh explained that the research provided new insights into the epithelium-protecting
and tumor-suppressive actions of metformin.
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Cancer fighting properties
Dr. Timothy Byun is a medical oncologist with the
Center for Cancer Prevention and Treatment at St. Joseph Hospital in Southern California.
He told Healthline that metformin has several mechanisms that may contribute
to its anticancer property.
Byun said multiple epidemiologic studies show an association between metformin
use and reduced cancer incidence and mortality.
“It's also well-known that individuals with diabetes or metabolic
syndromes have increased insulin production or insulin-resistance state.
Hyperinsulin state is associated with increased risk of certain cancers,”
He explained that metformin has insulin-lowering activity. This may slow
cancer in hyperinsulinemic patients.
It also suppresses production of adenosine triphosphate (ATP). ATP transports
energy within cells.
By suppressing it, cancer cells have less energy available. This makes
it harder for cancer cells to spread or survive.