Copper-Mediated Breast Cancer Protection With Genistein
Posted Dec 15 2010 10:00am
Population-based breast cancer research has repeatedly reported that dietary soy and soy isoflavone consumption has breast cancer fighting benefits including possibly reducing breast cancer risk and reducing the risk of breast cancer recurrence. While the possible breast cancer fighting benefits of soy consumption are apparently becoming clearer, the mechanism(s) by which soy isoflavones protect against breast cancer are uncertain.
A new breast cancer cell culture research stud y examined one possible mechanism by which the soy isoflavone genistein might fight breast cancer. For this study, breast cancer researchers cultured 2 breast cancer cell lines and one healthy, non-cancerous, breast cell line. These three cell lines were then treated with the soy isoflavone genistein at different doses to determine it's effects on these breast cancer cells and non-cancerous breast cells. The breast cancer investigators reported
Treatment with genistein reduced the growth of both breast cancer cell lines, but did not effect the growth of normal, non-cancerous breast cells.
Genistein treatment induced an internal fragmentation and death of breast cancer cells, but not normal breast cells.
Co-treating breast cancer cells with genistein plus a copper-binding compound prevented genistein from killing breast cancer cells and reducing their growth.
Treatment with genistein reduced the metastatic potential of the metastatic breast cancer cell line and co-treatment with the copper binding compound reversed this beneficial effect.
This is a fascinating cell culture study that describes one possible mechanism by which the soy isoflavone genistein might protect against breast cancer. Previous research has shown that breast cancer and many other cancers are accompanied by an elevation in blood, tissue, and cellular levels of copper and that the increased cellular levels of copper are restricted specifically to the cancer cells. This new breast cancer study suggests that genistein reduces breast cancer cell growth and causes the death of breast cancer cells through a copper-mediated mechanism. When the copper was available to be acted upon by genistein, breast cancer protection effects were observed. In comparison, when copper was made unavailable by adding a copper binder to the cell culture system, genistein's ability to suppress breast cancer cell growth was blocked. Overall, this suggests that genistein targets elevated copper levels in breast cancer cells to suppress their growth and viability. Furthermore, this also appears to explain the lack of an effect of genistein on normal, healthy breast cells, which do not have elevated copper levels. It would be interesting to know whether the other soy isoflavones, daidzein and glycitein, have similar copper-mediated effects and if the three combined together as found in most soy foods have a greater effect.