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Abstract

Tetrabromobisphenol A (TeBBPA) is a four-meta-brominated variant of bisphenol A (BPA) and is one of the most commonly used brominated flame retardants worldwide. We compared the estrogenic potency of TeBBPA, BPA and the brominated analogs mono- (MBBPA), di- (DBBPA), and tribromobisphenol A (TrBBPA) in the estrogen-dependent human breast cancer cell line MCF-7. All of the compounds competed with 17beta-estradiol for binding to the estrogen receptor, although the affinity of the test chemicals to the estrogen receptor was much lower than that of 17beta-estradiol. TrBBPA and TeBBPA showed a considerably lower access to the estrogen receptors within intact MCF-7 cells incubated in 100% serum compared to incubation in serum-free medium, indicating a strong binding to serum proteins. BPA, MBBPA, and DBBPA showed only a slightly reduced access to the receptors. All of the test compounds induced proliferation in MCF-7 cells, the potential decreasing with increasing number of bromo-substitutions. TeBBPA did not induce maximal cell growth, indicating cytotoxic effects at high concentrations. BPA and the brominated analogs, except TeBBPA, induced progesterone receptor and pS2 to the same extent as 17beta-estradiol, although at much higher concentrations. Our studies demonstrate that compared to 17beta-estradiol, BPA and the brominated analogs have much lower estrogenic potencies for all of the endpoints tested, TeBBPA being the least estrogenic compound.

Phthalates and other additives in plastics: human exposure and associated health outcomes

“…BISPHENOL A (a) Exposure BPA is used in a variety of consumer products, including epoxy resins that are used to line food cans (Kang et al 2003), polyester -styrene (Factor 1998) and polycarbonate plastics used for baby bottles and other containers (Brede et al 2003). BPA-containing resins and plastics are also used in some dental sealants (Sasaki et al 2005) and fillings ( Joskow et al 2006), adhesives, protective coatings, flame retardants (Samuelsen et al 2001) and water storage tanks and supply pipes (Bae et al 2002). BPA is a polymer, but degrades into its monomeric form over time, a process that can be accelerated by heat exposure (Brotons et al 1995).…”

Components of plastic: experimental studies in animals and relevance for human health

“…In vitro studies indicate that the lower brominated forms of TBBPA have higher affinity with the ER than the higher brominated analogues (Samuelsen et al 2001). In MCF-7 human breast cancer cells, TBBPA functioned as a partial ER agonist (Olsen et al 2003) and demonstrated mixed agonist/antagonist activities in estrogen responsive element (ERE)-luciferase reporter gene assays.…”

Disposition and kinetics of tetrabromobisphenol A in female Wistar Han rats

“…In studies using the estrogen-dependent rat pituitary tumor cell line MtT/E-2, TBBPA enhanced proliferation but to a lower extent than its non-brominated analog, bisphenol A [25]. TBBPA binds to the estrogen receptor, but to a lower degree than bisphenol A [33]. TBBPA was an estrogen receptor subtype alpha (ERα) agonist and a progesterone receptor (PR) antagonist in transfected yeast.…”

“…TBBPA was an estrogen receptor subtype alpha (ERα) agonist and a progesterone receptor (PR) antagonist in transfected yeast. TBBPA and two metabolites (2,6-dibromo-4-[2-hydroxypropane-2-yl]-phenol and 2,6-dibromo-4-[2-methoxypropane-2-yl]-phenol) have been shown to have estrogenic activity in MCF-7 cells [26], [33], [39]. TBBPA has been shown to be an inhibitor of estradiol sulfation in vitro [19].…”