Metformin Treatment Caused Cancer Stem Cell Death in Pancreatic Cancer Cell Lines
- Cancer stem cells sensitive to metabolic reprogramming with metformin.
- Metformin effectively combined with standard pancreatic treatments.
- Approach ready for clinical trials.
LAKE TAHOE, Nev. — Results of some preclinical trials have shown that low doses of the antidiabetic drug metformin may effectively destroy cancer stem cells, a group of cells that are considered to be responsible for tumor initiation and, because they are resistant to standard chemotherapies, tumor relapse.
In addition, when metformin was combined with a standard chemotherapy used for pancreatic cancer, the combination treatment was able to efficiently eradicate both cancer stem cells and more differentiated cancer cells, which form the bulk of the tumor, according to data presented by Christopher Heeschen, M.D., Ph.D., at the American Association for Cancer Research’s Pancreatic Cancer: Progress and Challenges conference, held in Lake Tahoe, Nev., from June 18-21, 2012. Heeschen is professor for experimental medicine at the Spanish National Cancer Research Centre in Madrid, Spain.
Most clinical trials of pancreatic cancer conducted during the last 15 years have failed to show marked improvement in median survival, suggesting that the selected approaches were not sufficient for several reasons, according to Heeschen. In recent years, researchers have identified cancer stem cells which, as opposed to the cancer cells that make up the bulk of the tumor, are a small subset of cells that are resistant to conventional therapy.
“Therefore, efficiently targeting these cells will be crucial for achieving higher cure rates in patients with pancreatic cancer,” he said. “Our newly emerging data now indicate that metformin, a widely used and well-tolerated drug for the treatment of diabetes, is capable of efficiently eliminating these cells.”
Specifically, the researchers found that metformin-pretreated cancer stem cells were particularly sensitive to alterations to their metabolism through the activation of AMPK. In fact, metformin treatment resulted in the death of cancer stem cells. In contrast, treatment of more differentiated cancer cells with metformin only arrested the cells’ growth.
“As the cancer stem cells represent the root of pancreatic cancer, their extinction by reprogramming their metabolism with metformin in combination with the stalling of the proliferation of more differentiated cells should result in tumor regression and long-term, progression-free survival,” Heeschen said.
The researchers generated data to support this idea when they treated immunocompromised mice implanted with a diverse set of patient-derived tumors with a combination of metformin and gemcitabine, the standard chemotherapeutic treatment for pancreatic cancer. They found that the treatment resulted in reduced tumor burden and the prevention of relapse as compared with treatment with either drug alone.
“Intriguingly, in all tumors treated with metformin to date, relapse of disease was efficiently prevented and there were no noticeable adverse effects,” Heeschen said.
He believes that testing metformin in pancreatic cancer is ready for clinical trials. The pancreatic research team is currently awaiting results of a study that tested metformin as a maintenance treatment in patients with advanced pancreatic cancer. Although the rationale for this study was based on retrospective data, Heeschen said given these new results he hopes that this treatment strategy would be highly efficacious.
“Pending the results of this study, an important aspect for the future will be to investigate if all patients respond to metformin or whether some patients, due to distinct genetic alterations, may not respond to this metabolic reprogramming,” he said.
About the AACR
Founded in 1907, the American Association for Cancer Research (AACR) is the world’s first and largest professional organization dedicated to advancing cancer research and its mission to prevent and cure cancer. AACR’s membership includes 34,000 laboratory, translational and clinical researchers; population scientists; other health care professionals; and cancer advocates residing in more than 90 countries. The AACR marshals the full spectrum of expertise of the cancer community to accelerate progress in the prevention, biology, diagnosis and treatment of cancer by annually convening more than 20 conferences and educational workshops, the largest of which is the AACR Annual Meeting with more than 17,000 attendees. In addition, the AACR publishes seven peer-reviewed scientific journals and a magazine for cancer survivors, patients and their caregivers. The AACR funds meritorious research directly as well as in cooperation with numerous cancer organizations. As the Scientific Partner of Stand Up To Cancer, the AACR provides expert peer review, grants administration and scientific oversight of individual and team science grants in cancer research that have the potential for near-term patient benefit. The AACR actively communicates with legislators and policymakers about the value of cancer research and related biomedical science in saving lives from cancer.
For more information about the AACR, visit www.AACR.org.
In Lake Tahoe, June 18-20: