Diabetes Drug Fights Breast Cancer - Metformin Kills Breast Cancer Stem Cells, May Fight Many...

WebMD ^ | Sept. 14, 2009 - | Daniel J. DeNoon

[neverdem]

Metformin Kills Breast Cancer Stem Cells, May Fight Many Cancers

Reviewed by Louise Chang, MD

The next breakthrough breast cancer treatment may be a diabetes drug already on the shelves of nearly every pharmacy.

The drug is metformin, available generically and under brand names such as Glucophage and Fortamet. A growing body of evidence suggests that diabetes patients taking metformin are less likely to get cancer, and have better outcomes if they do get cancer, than those not taking the drug.

Now Harvard researcher Kevin Struhl, PhD, and colleagues find that metformin can kill breast cancer stem cells, thought to be the cells responsible for breast cancer spread and recurrence.

And in mice carrying human breast cancers, metformin made standard chemotherapy vastly more effective. Mice treated with the combination remain cancer-free for four months, unlike mice treated with either drug alone.

"We have discovered new properties of metformin that can be of some use in cancer treatment and even prevention," Struhl said at a news conference held to announce the findings.

While his current study looked at metformin's effects on breast cancer, Struhl says the drug may affect other types of cancer as well.

"Although our studies were pretty much done on breast cancer cells, a lot of the principles are not specific just to breast cancer," Struhl said. "A lot of data shows lower cancer risk -- not just breast cancer -- in people taking metformin for diabetes."

Metformin Kills Cancer Stem Cells What's so special about yet another drug that kills cancer cells in mice?

For one thing, the kind of cancer cells metformin targets are cancer stem cells, which are resistant to standard chemotherapy.

"This is the first time it's been shown that metformin may have an effect on these very resistant cancer cells. It is very exciting research," Dana-Farber Cancer Institute researcher Jennifer A Ligibel, MD, said at the news conference.

The very existence of cancer stem cells has been debated. That debate is now "water under the bridge," Frank Rauscher, PhD, suggested at the news conference. Rauscher, a cancer researcher at the Wistar Institute, is editor-in-chief of Cancer Research, which published the Struhl study in today's advance online edition.

Struhl says cancer stem cells are "far more nasty" than regular cancer cells.

"The bulk of the cells in a tumor are cancer cells which grow but are killed by chemotherapy," Struhl says. "But there is also a small population of cancer stem cells, which are better able to form tumors on their own and more resistant to chemotherapy than cancer cells. After standard chemotherapy, they can remain and essentially regenerate the tumor, and the disease is back again."

Different researchers have recently described new compounds that selectively kill cancer stem cells. Whether these compounds might one day become safe and effective cancer drugs remains to be shown.

Struhl -- who, with Harvard Medical School, holds a patent on the combined use of metformin and low-dose chemotherapy -- says metformin is already known to be safe and merely needs to be proven effective in human clinical trials.

Easier Cancer Chemo With Metformin? Another reason researchers are excited about the study findings is that metformin and standard chemotherapy seem to make each other work better.

"Because of this synergy with chemotherapy, metformin could be used with lower doses of chemotherapy," Struhl suggests. "Chemotherapy is quite a toxic thing for people to deal with, and if one could lower the dose that would be very nice."

Metformin itself has an outstanding safety record.

"This drug at low doses can be considered a very good candidate for cancer prevention before a person has any cancer at all," Rauscher said. "The hope is we can use a drug like metformin and continue to deplete the levels of these inherently chemotherapy-resistant, dormant cancer stem cells."

Can Metformin Prevent Breast Cancer Recurrence? Ligibel, who was not involved in the Struhl study, has argued that metformin should be tested in people.

Taking her own advice, she is participating in a human study led by Canada's national cancer institute that will test whether metformin can prevent breast cancer from coming back after treatment. The study, which will take place at multiple cancer centers in Canada and the U.S., has not yet begun enrollment.

Unfortunately, Ligibel said, there are no plans for studies combining metformin with chemotherapy. But Struhl said that because metformin is an approved drug, such studies could begin relatively soon.

"We are hoping for researchers to actually try that experiment," Struhl said. "The idea of using this as a combined treatment is the main point of our paper."

"These concepts should be moved forward in clinical trials," Rauscher agreed.

[neverdem]

Metformin Selectively Targets Cancer Stem Cells, and Acts Together with Chemotherapy to Block Tumor Growth and Prolong Remission

[kcvl]

You always find the best medical articles.

Thanks!

[neverdem]

Cancer stem cell treatment with metformin, a type 2 diabetes drug, might yield some interesting insights in basic cell biology, not to mention treating cancer.

[neverdem]

You’re welcome. It’s my pleasure.

[celtic gal]

great news

[Aria]

I just sent this to a friend who just had a recurrence of BC and had to have a double mastectomy and is now going through the hell of chemo.

Thank you for posting.

[Gator113]

And it’s to our benefit... Thank you.

[Irish Eyes]

Thanks for the ping

[Dubya]

Thanks for this post.

[steve86]

Silver lining to having Type II

[radiohead]

<Silver lining to having Type II

Apparently one of the few - if you can stand the gastric upset. I wish I could take more of it, but just can’t deal with it in more than low doses.

I have a friend who was diagnosed with BC this summer. They are urging tamoxifen, but she only needed radiation and is afraid of taking anything with such heavy side effects for 5 years. I’m going to let her know about this study; maybe she can talk her doctor into trying something less stressful on the body than tamoxifen.

[diamond6]

ping

[neverdem]

Artificial ionosphere creates bullseye in the sky Auroral experiments make glowing plasma patch.

Nerve gas detection in a fraction of a second

Health drink ready to flow (Water with Omega 3) How do they dissolve an oil, Omega-3 fatty acids, in water?

Umbilical Cord Blood As A Readily Available Source For Off-the-shelf, Patient-specific Stem Cells

FReepmail me if you want on or off my health and science ping list.

[muawiyah]

This is the first positive news I've ever seen about having Type II.

Both glucophage and glipizide communicate directly with things on the inside of cells.

[nina0113]

Thanks - I switched from metformin to insulin b/c of side effects, but in light of this, they weren’t so bad, really.

[bmwcyle]

ping

[GOPJ]

Thanks for the ping.

[muawiyah]

Think about it a moment ~ maybe one of the "side effects" is a consequence of metaformin's effect on cancer cells ~ seems to me it could serve as a diagnostic guide, not just as a treatment.

Ask your doctor to check it out ~ take this article with you BTW.

[rahbert]

My blood glucose is out of control most days (>200 until the afternoon), I’m on Actos, and am wondering what the doc will prescribe at my next visit this Friday.

I will ask about Met since the side effects don’t seem all that serious.

[nina0113]

The side effect that caused me to stop taking it was that I had to take one Imodium-AD for each metformin tablet, so probably not, but I am taking a copy of the article to my next appointment.