Differences in the mechanisms of action of BDE-47 and its metabolites on OVCAR-3 and MCF-7 cell apoptosis (original) (raw)
Related papers
Journal of applied toxicology : JAT, 2016
Data concerning the possible action of polybrominated diphenyl ethers (PBDEs) in hormone-dependent cancer are scarce. Some data showed that PBDEs may directly affect breast cancer cells formation and only one research showed increased proliferation of the OVCAR-3 cells, but the results are ambiguous and the mechanisms are not clear. There is growing evidence that not only parent compounds but also its metabolites may be involved in cancer development. The present study was, therefore, designed to determine the effect of BDE-47 and its metabolites (2.5 to 50 ng ml(-1) ) on proliferation (BrdU), cell-cycle genes (real-time PCR) and protein expression (Western blot), protein expression of oestrogen receptors (α β), extracellular signal-regulated kinases 1 and 2 (ERK1/2) and protein kinase Cα (PKCα) in OVCAR-3 ovarian and MCF-7 breast cancer cells. In OVCAR-3 cells, the parent compound stimulated cell proliferation by activating CDK1, CDK7, E2F1 and E2F2. Independent of time of exposure...
Archives of Pharmacal Research, 2007
In this study, we investigated the effects of 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (TDB), isolated fromSymphyocladia latiuscula (marine red algae), on the proliferation of MCF-7 human breast cancer cells. TDB treatment for 48 h inhibited cancer cell growth and induced DNA fragmentation. Furthermore, morphological characterizations such as apoptotic bodies and membrane blebs were shown by electronic microscopy. TDB-induced apoptosis in the MCF-7 cells was closely linked with the down-regulation of Bcl-2 protein expression and the cle⇑age of caspase-3 substrates, with poly(ADP-ribose) polymerase cleavage occurring by TDB treatment. TDB treatment also caused a marked increase in the level ofp21 WAF1/CIP1 protein in a p53-dependent manner. In addition, the upregulation ofp21 WAF1/CIP1 in the MCF-7 cells was related to a decrease in c-Myc protein in a dose-dependent manner. Based on our data, TDB is a good candidate for further evaluation as an effective chemotherapeutic agent, acting through the induction of apoptosis.
Toxicology in Vitro, 2010
Recently, the environmental residues of polybrominated diphenyl ethers (PBDEs) have markedly increased. In particular, the levels of certain PBDE congeners in fish have raised concern regarding potential risks associated with dietary PBDEs exposures. However, little is known regarding PBDE-mediated cell injury in relevant in vitro fish cell models. In this study, the cytotoxic effects of 2,2 0 ,4,4 0 -tetrabromodiphenyl ether (BDE-47) and decabrominated diphenyl ether (BDE-209) on RTG-2 cells were investigated.
Environment International, 2010
Several studies suggest an involvement of PCBs in breast cancer formation, but the results are ambiguous and the mechanisms not clear. We propose that local activation of cytochrome P450 enzymes, CYP1A1 and CYP1B1 by PCB3, may generate active metabolites which affect apoptosis and thereby promote mammary carcinogenesis. To test this hypothesis MCF-7 human breast cancer cells were exposed to 300 nM PCB3 and its hydroxylated metabolites, 4OH-PCB and 3,4diOH-PCB3. The enzyme activity for CYP1A1 was assayed using the EROD assay, and CYP1A1 and CYP1B1 protein expression by western blotting. PCB3 increased CYP1A1 activity (~1.5fold) and protein levels within 6 h after exposure. No effect on CYP1B1 protein expression was observed. The effects of PCB3 and both its metabolites on staurosporine-induced apoptosis were determined by measuring DNA fragmentation using ELISA and TUNEL assays, and by measuring caspase-8 and caspase-9 activity. We found that PCB3 and both of its hydroxylated metabolites had no effect on caspase-8 and caspase-9 activity when cells were grown in medium deprived of estrogen, but reduced caspase-9 activity when cells were grown in medium supplemented with serum containing estradiol. Interestingly, a decrease of DNA fragmentation was observed upon treatment with 3,4diOH-PCB3 in both culture conditions, suggesting that 3,4diOH-PCB3 affects a caspase-independent pathway of cell death. In summary, interactions of PCB3 and its metabolites with estradiol by yet unknown mechanisms inhibit caspase 9-related apoptosis and additional, other death pathways are affected by the catechol metabolite 3,4diOH-PCB3. These anti-apoptotic effects and the change in metabolic activity may contribute to the carcinogenic effect of PCBs.
Toxicology, 2018
In this study, HepG2 cells were exposed to 6-hydroxy- 2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE-47) for 3 and 6 days for monitoring cytotoxic effects and alterations in its transcriptomic profile. MTT assay showed that cells exposed to 6-OH-BDE-47 (50 nM) exhibited 48.5% and 53.7% decline in cell survival after 3 and 6 days. Neutral red uptake (NRU) assay also demonstrated 47.1% and 56% reduction in cell survival at 50 nM, indicating lysosomal toxicity. The flow cytometric data confirmed an increase in intracellular reactive oxygen species (ROS) and mitochondrial dysfunction (ΔΨm). In comet assay, HepG2 cells exposed to 6-OH-BDE-47 (50 nM) showed 7.6-fold greater DNA damage. Cell cycle data revealed G/M arrest at 10 and 25 nM after 3 days of exposure, while 50 nM induced mild apoptotic effect. The intensity of apoptosis increased after 6 days of exposure with 21.5%, 47% and 99.1% of cells recorded in subG1 apoptotic phase vis-à- vis the control showed 14.5% background apo...
BDE-99 congener induces cell death by apoptosis of human hepatoblastoma cell line – HepG2
Toxicology in Vitro, 2013
Polybrominated Diphenyl Ethers (PBDEs) are an important class of flame retardants with a wide range of toxic effects on biotic and abiotic systems. The toxic mechanisms of PBDEs are still not completely understood because there are several different congeners with different chemical and biological characteristics. BDE-99 is one of these, widely found in the environment and biological samples, showing evidence of neurotoxic and endocrine disruption activities, but with little information about its action mechanism described in the current literature. This work investigated the effects of BDE-99 on the HepG2 cell line in order to clarify its toxic mechanism, using concentrations of 0.5-25 lM (24 and 48 h). Our results showed that BDE-99 could cause cell death in the higher concentrations, its activity being related to a decrease in mitochondrial membrane potential and an accumulation of ROS. It was also shown that BDE-99 induced the exposure of phosphatidylserine, caspases 3 and 9 activation and DNA fragmentation in HepG2 cells, without causing the release of LDH. Thus it was shown that BDE-99 could cause HepG2 cell death by apoptosis, suggesting its toxicity to the human liver.
Environmental Health Perspectives, 2009
Background: An increasing number of studies are reporting the existence of polybrominated diphenyl ethers (PBDEs) and their hydroxylated (HO) and methoxylated (MeO) metabolites in the environment and in tissues from wildlife and humans. oBjective: Our aim was to characterize and compare the agonistic and antagonistic activities of principle PBDE congeners and their HO and MeO metabolites against human nuclear hormone receptors. Methods: We tested the hormone receptor activities of estrogen receptor α (ERα), ERβ, androgen receptor (AR), glucocorticoid receptor (GR), thyroid hormone receptor α 1 (TRα 1), and TRβ 1 against PBDE congeners BDEs 15, 28, 47, 85, 99, 100, 153, and 209, four para-HO-PBDEs, and four para-MeO-PBDEs by highly sensitive reporter gene assays using Chinese hamster ovary cells. results: Of the 16 compounds tested, 6 and 2 showed agonistic activities in the ERα and ERβ assays, respectively, and 6 and 6 showed antagonistic activities in these assays. 4´-HO-BDE-17 showed the most potent estrogenic activity via ERα/β, and 4´-HO-BDE-49 showed the most potent anti estrogenic activity via ERα/β. In the AR assay, 13 compounds showed antagonistic activity, with 4´-HO-BDE-17 in particular inhibiting AR-mediated transcriptional activity at low concentrations in the order of 10-8 M. In the GR assay, seven compounds, including two HO-PBDEs and two MeO-PBDEs, showed weak antagonistic activity. In the TRα 1 and TRβ 1 assays, only 4-HO-BDE-90 showed weak antagonistic activity. conclusions: Taken together, these results suggest that PBDEs and their metabolites might have multiple endocrine-disrupting effects via nuclear hormone receptors, and para-HO-PBDEs, in particular, possess more potent receptor activities compared with those of the parent PBDEs and corresponding para-MeO-PBDEs.
A 2-methoxyestradiol bis-sulphamoylated derivative induces apoptosis in breast cell lines
Cell & Bioscience, 2015
Introduction: Research involving antimitotic compounds identified 2-methoxyestradiol (2ME2), as a promising anticancer endogenous metabolite. Owing to its low bioavailability, several in silico-designed 2ME2 analogues were synthesized. Structure-activity relationship studies indicated that an already existing 17-β-estradiol analogue, namely (8R,13S,14S,17S)-2-ethyl- 13-methyl-7,8,9,11,12,13,14,15,16,17-decahydro-6H-cyclopenta[a]phenanthrane-3,17-diyl bis(sulphamate) (EMBS) to exert potential in vitro anticancer activity. Methods: This study investigated the in vitro apoptotic influence of EMBS in an estrogen receptor-positive breast adenocarcinoma epithelial cell line (MCF-7); an estrogen receptor-negative breast epithelial cell line (MDA-MB-231) and a non-tumorigenic breast cell line (MCF-12A). Cell cycle progression, a phosphatidylserine flip, caspase 6-, 7-and 8 enzyme activity levels, Bcl-2 phosphorylation status at serine 70 and Bcl-2-and p53 protein levels were investigated to identify a possible action mechanism for apoptotic induction. Results: The xCELLigence real-time label-independent approach revealed that EMBS exerted antiproliferative activity in all three cell lines after 24 h of exposure. A G 2 M block was observed and apoptosis induction was verified by means of flow cytometry using propidium iodide and Annexin V-FITC respectively. EMBS-treated cells demonstrated a reduced mitochondrial membrane potential. EMBS exposure resulted in a statistically significant increase in p53 protein expression, decreased Bcl-2 protein expression and a decrease in pBcl-2(s70) phosphorylation status in all three cell lines. Results support the notion that EMBS induces apoptosis in all three cell lines. Conclusion: This study includes investigation into the apoptotic hallmarks exerted by EMBS after exposure of three cell lines namely MCF-7-, MDA-MDA-231-and MCF-12A cells. Increased caspase 6-, caspase 7-and caspase 8 activities, upregulation of p53 protein expression and a decrease in phosphorylation status of Bcl-2 at serine 70 in tumorigenic and non-tumorigenic lines were demonstrated.