Phytoestrogens Induce Death of ER[-] Breast Cancer Cells
Posted Apr 18 2011 10:37am
With more and more scientific evidence showing that soy isoflavones and other phytoestrogens might have an important role in breast cancer protection, it becomes more important to clearly understand how these naturally occuring plant chemicals act to fight breast cancer. While these phytoestrogens can work through estrogen receptors in cells that have estrogen receptors, different mechanisms are needed in estrogen receptor negative (ER[-]) breast cancer cells.
A recent breast cancer study published last month in the journal Nutrition Research examined the possible mechanisms of action of three phytoestrogens, genistein, apigenin, and quercetin, in ER[-] breast cancer cells. For this study, the investigators cultured and ER[-] breast cancer cells, treated them the three phytoestrogens separately, and examined changes in chemicals and genes involved in cell growth. The researchers reported that
All three phytoestrogens suppressed of ER[-] breast cancer cells.
Suppression of cell growth was accompanied by an increase in the programmed death of ER[-] breast cancer cells.
Examination of cellular changes showed that the level of the active form of the p53 tumor suppressor gene was enhanced by all three phytoestrogens
These phytoestrogens also enhanced the level of the p21 gene, which is an important cell growth regulator that is controlled by the p53 tumor suppressor gene.
Genistein, apigenin, and quercetin each decreased the level of the cell molecule Bcl-xL, a molecule thought to be important for the survival of breast cancer cells.
This is an interesting cell culture study that suggests the phytoestrogens genistein, apigenin, and quercetin can each inhibit the growth of ER[-] breast cancer cells. This inhibition appears to be through complementary actions of increasing the level of genes involved in cell growth suppression and decreasing the level of genes involved in cell growth promotion. These results support the concept that these phytoestrogens might be beneficial compounds in the fight against breast cancer. While it will take time before the utility of these phytoestrogens in a clinical setting is fully realized, each of these phytoestrogens can be obtained in our diet. Genistein is one of the main isoflavones in soybeans and soy foods; apigenin can be obtained from celery, rutabagas, and other vegetables; quercetin is found in numerous vegetables including onions, kale, broccoli, and hot peppers. Eating a wide variety of fruits and vegetables is the best way to obtain these and other naturally occurring phytoestrogens.