Bisphenol-A causes Normal Breast Cells to act like Cancer
BPA may limit the effectiveness of commonly used anti-cancer drugs
SACRAMENTO, Calif., September 12, 2011 - A study published in the Oxford University Press journal, Carcinogenesis, concludes that healthy breast cells exposed to bisphenol-A (BPA) and methylparaben, a common ingredient in beauty products, change from normal and begin to grow and survive like cancer cells. This new research also indicates that BPA exposure may reduce the effectiveness of certain popular and promising breast cancer drugs.
“Flipping the Switch” for Growth
Exposure to the chemicals BPA and methylparaben activates mTOR, a cell’s central mechanism to control cancer growth. When the mTOR signal is turned off, cancer cells do not survive, however, once mTOR is activated, cancer cells can grow and thrive.
“Not every cell exposed to BPA or methylparaben will become cancer, but anything – any chemical exposure – that “flips the switch” and causes healthy cells to act like cancer is cause for concern,” says Dr. William Goodson, lead author and Senior Clinical Research Scientist at California Pacific Medical Center Research Institute.
Effects of BPA are important because of the chemical’s widespread exposure. BPA is found in many household items, including plastic food containers, the lining of canned food and soda cans, water bottles, other plastic items, and some types of cash register receipts. Random samples taken by the Centers for Disease Control and Statistics Canada have shown that more than 95 percent of Americans and 90 percent of Canadians test positive for BPA.
Impact on Cancer Fighting Drugs
In addition to changing the way cells act, the study concludes that BPA has an impact on the effectiveness of popular cancer fighting drugs. “Healthy breast cells exposed to the cancer preventing and cancer treating drug Tamoxifen should undergo “programmed cell death” or apoptosis, but after BPA exposure they don’t,” explains Dr. Shanaz Dairkee, co-leader of the project and Senior Scientist at CPMC Research Institute. BPA also prevents apoptosis by the drug Rapamycin, the lead drug in a new class of cancer drugs designed to turn off the mTOR gene. She continued, “Having two breast cancer drugs rendered ineffective by BPA exposure is very concerning for women who are battling breast cancer.”
“We don’t know yet how reversible these effects of BPA are, particularly if cancer has already developed,” says Dr. Goodson. “But it is intriguing to speculate that reducing BPA exposure might have a beneficial effect on any malignant changes that have been induced, and even decrease the overall risk of cancer.”
New Research Methodology Used
Unlike studies that focus on cells after they become cancerous, this study breaks new ground by focusing on the role of BPA and methylparaben in changing the growth of healthy cells before they become cancer. Using techniques developed by Dr. Dairkee at the CPMC Research Institute, Drs. Goodson and Dairkee took healthy breast epithelial cells from women considered at high risk for developing breast cancer. The samples came from 23 women; 16 of the women had a personal history of breast cancer, the other seven were considered at high risk of developing breast cancer. The samples were then grown and exposed to BPA at levels consistent with those found today in human blood, placenta and breast milk. This new methods allows a wider sample from the whole population so the results are more applicable to women in general.
Dr. Goodson says, “The evidence is strong and getting stronger, that BPA poses a real threat to people, and it’s time to take it out of the food chain.” He continued, “But real change will need the support of everyone. Up to now, industry has avoided having to prove that the chemicals they use are not harmful. This kind of data shifts the responsibility. Industry should now be told to show us that these chemicals are safe.”
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