Bisphenol en kanker*
Uit een celstudie blijkt dat bisphenol kankercellen beschermd tegen doodgaan. Bisphenol A is een chemische stof die wordt gebruikt voor de productie van polycarbonaat, een transparante plastic die onder andere gebruikt wordt als drager van CD's en DVD's en voor onbreekbare flessen voor (baby)voeding, voor tafelbestek, en voorwerpen voor gebruik in microgolfovens. Het wordt ook gebruikt in epoxyharsen die als beschermende coating aan de binnenkant van voedingsverpakkingen in blik of karton worden aangebracht, of in leidingen en reservoirs voor drinkwater. Bisfenol A wordt ook gebruikt in vlamvertragende middelen, ook in tandvullingen en als oplosmiddel voor drukinkten. In de studie werden borstkankercellen behandeld met kleine hoeveelheden bisphenol A, vergelijkbare hoeveelheden die
doorgaans al in veel mensen aangetroffen worden. Bisphenol lijkt chemisch gezien veel op de kankerverwekkende stof DES. Doch Bisphenol laat niet zoals Des de kankercellen verder groeien maar voorkomt dat kankercellen gedood worden door stoffen zoals die gebruikt worden bij een chemokuur. Deze studie laat zien dat Bisphenol A gevaarlijk is voor de mens.
Link Between Bisphenol A And Chemotherapy Resistance
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..
"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.
The cancer and cell biology department at UC is part of a joint cancer program involving the UC College of Medicine, Cincinnati Children's Hospital Medical Center and University Hospital. The collaborative initiative brings together interdisciplinary research teams of caring scientists and health professionals to research and develop new cures, while providing a continuum of care for children, adults and families with cancer.
Source: Dama Kimmon University of Cincinnati (November
2008)
