Metformin + Trastuzumab Therapy Suppresses Cancer Stem Cells
Posted May 17 2010 7:44am
Several studies have now shown that breast cancer tumors possess a population of cells called stem cells that are relatively resistant to both radiation and chemotherapy and are capable of self-renewal. It has been suggested that these breast cancer stem cells drive tumor formation, metastasis, and breast cancer recurrence. A new breast cancer study explored the effect of metformin , an anti-diabetic drug, on HER2-positive breast cancer cells.
In this new breast cancer study , researchers cultured three different types of HER2-positive breast cancer cells, one type which was sensitive to the anti-HER2 drug trastuzumab and two types that were resistant to trastuzumab treatment. These breast cancer cells were treated with metformin alone, trastuzumab alone, or a combination of these two drugs. The breast cancer researchers showed that
Increasing doses of metformin alone showed increasing effectiveness at suppressing the growth and clumping of all three types of breast cancer cells.
Treatment with trastuzumab inhibited growth of only breast cancer cells that were known to be sensitive to this drug; trastuzumab-resistant breast cancer cells were not affected.
A combination of both metformin and trastuzumab treatments given together reduced growth and clumping of both trastuzumab-sensitive and trastuzumab-resistant breast cancer cells.
According to the study summary, these new results suggest that HER2-positive breast cancers that become resistant to trastuzumab treatment do so because of resistant breast cancer stem cells. Furthermore, these breast cancer research results suggest that the anti-diabetic drug metformin can help overcome this resistance.
These are potentially important results that will require further study in both pre-clinical and clinical trials. The development of drug-resistant breast cancers is not an uncommon phenomenon and can lead to breast cancer recurrence, difficulties in treatment, and poorer outcomes. New therapies that can overcome this resistance to original breast cancer therapy are needed and provide an opportunity to successfully treat breast cancer recurrence.
While advances in breast cancer therapy continue to be made, there are things we all can do on a daily basis that can reduce our breast cancer risk. To learn more about some of these easy diet and lifestyle changes that we can make, read my book Fight Now: Eat & Live Proactively Against Breast Cancer .