bisphenol A linked to chemotherapy resistance

[Lani]

Bisphenol A Linked to Chemotherapy Resistance
[University of Cincinnati Medical Center]
CINCINNATI—Exposure to bisphenol A (BPA) may reduce the effectiveness of chemotherapy treatments, say University of Cincinnati (UC) scientists.
The research study, led by UC's Nira Ben-Jonathan, PhD, says that BPA—a man-made chemical found in a number of plastic products, including drinking bottles and the lining of food cans—actually induces a group of proteins that protect cancer cells from the toxic effects of chemotherapy.
The findings are reported in the journal Environmental Health Perspectives and appear online Oct. 8, 2008, ahead of print.
"Resistance to chemotherapy is a major problem for cancer patients, especially those with advanced or metastatic disease," says Ben-Jonathan, a professor of cancer and cell biology at UC who has studied BPA for more than 10 years. "Finding out what contributes to that resistance can give us an idea of what to target in order to make chemotherapy as effective as possible."
Researchers have suspected that BPA could play a role in cancer because of the chemical's structural similarities to a cancer-promoting compound called diethylstilbestrol (DES). But Ben-Jonathan's team found that BPA isn't exactly mimicking the action of DES.
"BPA does not increase cancer cell proliferation like DES does," she says. "It's actually acting by protecting existing cancer cells from dying in response to anti-cancer drugs, making chemotherapy significantly less effective."
Ben-Jonathan's team studied human breast cancer cells, subjecting them to low levels of BPA consistent with levels found in the blood of human adults. The team found that BPA is acting in cancer cells similar to the way estrogen does—by inducing proteins that protect the cells from chemotherapy agents.
Estrogen's protein-inducing action has been previously linked to chemotherapy resistance, but researchers have been unable to explain why such resistance still occurs in certain patients with less estrogen. Ben-Jonathan says her team's research has important implications for this subgroup of patients.
"Patients with less circulating estrogen—post-menopausal women, for example—can also suffer from chemotherapy resistance," she says. "Linking BPA to this problem gives us one more avenue to explore in terms of preventing chemotherapy resistance."
"These data," study authors write, "provide considerable support to the accumulating evidence that BPA is hazardous to human health."
Coauthors include Elizabeth LaPensee, Sejal Fox and Traci Tuttle.
The study was funded by grants from the National Institutes of Health, the Department of Defense and the Susan G. Komen Breast Cancer Foundation.

http://www.ehponline.org/members/2008/11788/11788.pdf

Bisphenol A at Low Nanomolar Doses Confers
Chemoresistance in Estrogen Receptor Alpha Positive and Negative Breast Cancer Cells
[Environmental Health Perspectives]
Background: Resistance to chemotherapy is a major problem facing breast cancer patients, and identifying potential contributors to chemoresistance is a critical area of research. Bisphenol A (BPA) has long been suspected to promote carcinogenesis, but the high doses of BPA used in many studies generated conflicting results. In addition, the mechanism by which BPA exerts its biological actions is unclear. While estrogen has been shown to antagonize anti-cancer drugs, the role of BPA in chemoresistance has not been examined.
Objective: The objective was to determine whether BPA at low nanomolar concentrations opposes the action of doxorubicin, cisplatin and vinblastine in the ERα positive T47D and the ERα negative MDA-MB-468 breast cancer cells.
Methods: The responsiveness of cells to anti-cancer drugs and BPA was determined by the MTT cytotoxicity assay. Specific ERα and ERβ inhibitors and real-time PCR were used to identify potential receptor(s) that mediate the actions of BPA. Expression of anti-apoptotic proteins was assessed by Western blotting.
Results: BPA antagonizes the cytotoxicity of multiple chemotherapeutic agents in both ERα positive and negative breast cancer cells independent of the classical ERs. Both cell types express alternative ER receptors, including GRP30 and members of the estrogen related receptor (ERR) family. Increased expression of anti-apoptotic proteins is a potential mechanism by which BPA exerts its anti-cytotoxic effects.
Conclusions: BPA at environmentally relevant doses reduces the efficacy of chemotherapeutic agents. These data provide considerable support to the accumulating evidence that BPA is hazardous to human health.

[hutchibk]

Wow! - Time to buy yourselves a stainless steel travel cup and fill it with your home-filtered tap water. Just say no to plastic water bottles... either that or only buy bottled water in glass. From time to time, I find cases of glass bottled water on a great sale, and I buy it up when I do, but usually it's too expensive.

And whatever you do, don't drink out of plastic water bottles after they have been sitting in the sun in a hot car!

[Rich66]

Ok..so orange juice in a plastic bottle is a double whammy. Do foam cups, like ones in hospitals, have this issue?

[CLTann]

Bisphenol A is a component chemical used in the synthesis of polycarbonate. Polycarbonate is a class of polymer that are impact resistant and generally unbreakable. It lends itself in many applications where breakage must be avoided. Polyethylene, polypropylene and polystyrene are used for making low cost white cups.

[penelope]

Ok so why are we surprised! This has been a continuing issue, but I was unaware that it lined my canned food. Does this mean it is in the coatings of paper containers like milk?

[Rich66]

Panel Criticizes FDA Bisphenol A Report

from WebMD — a health information Web site for patients

Miranda Hitti

Information from Industry


Assess clinically focused product information on Medscape.
Click Here for Product Infosites – Information from Industry.

October 30, 2008 — The controversy over the plastic chemical bisphenol A is heating back up, with a panel of scientists criticizing an FDA draft report on bisphenol A safety.
Bisphenol A, also called BPA, is a chemical found in polycarbonate plastic -- including some water bottles and baby bottles -- and in the lining of canned goods.
Some research, mostly done on animals, suggests possible health risks from bisphenol A exposure, especially early in life. But an FDA draft report says bisphenol A is safe at typical exposure levels from food and drink.
Now, an independent subcommittee has reviewed the FDA draft report, at the FDA's request, and has posted these criticisms:

• Some studies were excluded without enough explanation.
• Uncertainty in bisphenol A research wasn't mentioned enough.
• The FDA's margins of safety for bisphenol A are "inadequate."
• More attention should have been paid to infants' exposure to bisphenol A.

Removing Bisphenol A From Baby Bottles?
The American Chemistry Council, a plastics industry trade group, issued a statement about the review of the draft report.
In that statement, the council pledges to abide by whatever the FDA decides about bisphenol A.
"If the [FDA] determines that existing margins of safety are insufficient in infant applications, our member companies that manufacture BPA will put processes in place to promptly phase out the use of materials containing BPA in baby bottles and infant formula packaging," the council states.
The Natural Resources Defense Council (NRDC), a nonprofit group that wants bisphenol A banned in food containers, also issued a statement about the subcommittee's review.
"The FDA has consistently ignored science and sound policy, putting corporate interests ahead of public protection ... it's time for the FDA to protect infants and pregnant women," says NRDC reproductive biologist Sarah Janssen, MD, PHD.
FDA Responds
The scientific panel has raised "important questions," states an FDA news release. The FDA isn't brushing off those questions and calls for more research.
Meanwhile, the FDA hasn't changed its standards for bisphenol A safety -- or its advice to consumers.
"Consumers should know that, based on all available evidence, the present consensus among regulatory agencies in the United States, Canada, Europe, and Japan is that current levels of exposure to BPA through food packaging do not pose an immediate health risk to the general population, including infants and babies," the FDA states.
Last week, the Canadian government said it would ban bisphenol A in baby bottles. The FDA points out that that action was taken "out of an abundance of caution," and that Canadian scientists haven't found any proof of harm to babies with typical exposure to bisphenol A.
Here's where the FDA's draft report stands:

• It's already been discussed at a public meeting.
• It's gone through peer review -- that's the review by independent scientists.
• Next, an FDA advisory committee takes the topic up on Oct. 31.

Those are steps toward the FDA's final report on bisphenol A -- and there is no deadline for that.
SOURCES:
FDA Science Board Subcommittee on BIsphenol A: "Scientific Peer-Review of the Draft Assessment of BIsphenol A for Use in Food Contact Applications."
Statement, American Chemistry Council.
News release, Natural Resources Defense Council.

[DLL]

Is anyone aware of a list anyone has put together of the things to avoid during chemo that could diminish its effectiveness (e.g., mega-antioxidants, BPA, etc.)? Seems like a da*n shame to go through all this chemo only to be foiled unknowingly by something easily avoided!

[StephN]

"The research study, led by UC's Nira Ben-Jonathan, PhD, says that BPA—a man-made chemical found in a number of plastic products, including drinking bottles and the lining of food cans—actually induces a group of proteins that protect cancer cells from the toxic effects of chemotherapy."

This has been suspected as long as I have been fighting cancer - going on 9 years. We buy very little in cans anyway - tuna now comes in foil packs and soups in boxes.

I even have bottles to transfer things like salad dressings into. Still is hard to give up some things that have been packed in glass that are in plastic now. Mustard and mayo for instance.

Just have to keep thinking when we shop!