Dataset Information

Effects of Benzophenone-3 and Propylparaben on Estrogen Receptor-Dependent R-Loops and DNA Damage in Breast Epithelial Cells and Mice.

ABSTRACT: BACKGROUND:Endocrine-disrupting chemicals have been shown to have broad effects on development, but their mutagenic actions that can lead to cancer have been less clearly demonstrated. Physiological levels of estrogen have been shown to stimulate DNA damage in breast epithelial cells through mechanisms mediated by estrogen-receptor alpha (ER?). Benzophenone-3 (BP-3) and propylparaben (PP) are xenoestrogens found in the urine of >96% of U.S. POPULATION: OBJECTIVES:We investigated the effect of BP-3 and PP on estrogen receptor-dependent transactivation and DNA damage at concentrations relevant to exposures in humans. METHODS:In human breast epithelial cells, DNA damage following treatment with 17?-estradiol (E2), BP-3, and PP was determined by immunostaining with antibodies against ?-H2AX and 53BP1. Estrogenic responses were determined using luciferase reporter assays and gene expression. Formation of R-loops was determined with DNA: RNA hybrid-specific S9.6 antibody. Short-term exposure to the chemicals was also studied in ovariectomized mice. Immunostaining of mouse mammary epithelium was performed to quantify R-loops and DNA damage in vivo. RESULTS:Concentrations of 1?M and 5?M BP-3 or PP increased DNA damage similar to that of E2 treatment in a ER?-dependent manner. However, BP-3 and PP had limited transactivation of target genes at 1?M and 5?M concentrations. BP-3 and PP exposure caused R-loop formation in a normal human breast epithelial cell line when ER? was introduced. R-loops and DNA damage were also detected in mammary epithelial cells of mice treated with BP-3 and PP. CONCLUSIONS:Acute exposure to xenoestrogens (PP and BP-3) in mice induce DNA damage mediated by formation of ER?-dependent R-loops at concentrations 10-fold lower than those required for transactivation. Exposure to these xenoestrogens may cause deleterious estrogenic responses, such as DNA damage, in susceptible individuals. https://doi.org/10.1289/EHP5221.

SUBMITTER: Majhi PD

PROVIDER: S-EPMC7015622 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Effects of Benzophenone-3 and Propylparaben on Estrogen Receptor-Dependent R-Loops and DNA Damage in Breast Epithelial Cells and Mice.

Majhi Prabin Dhangada PD Sharma Aman A Roberts Amy L AL Daniele Elizabeth E Majewski Aliza R AR Chuong Lynn M LM Black Amye L AL Vandenberg Laura N LN Schneider Sallie S SS Dunphy Karen A KA Jerry D Joseph DJ

Environmental health perspectives 20200115 1

<h4>Background</h4>Endocrine-disrupting chemicals have been shown to have broad effects on development, but their mutagenic actions that can lead to cancer have been less clearly demonstrated. Physiological levels of estrogen have been shown to stimulate DNA damage in breast epithelial cells through mechanisms mediated by estrogen-receptor alpha (ERα). Benzophenone-3 (BP-3) and propylparaben (PP) are xenoestrogens found in the urine of >96% of U.S.<h4>Population</h4><h4>Objectives</h4>We investi ...[more]

PMID: 31939680

Similar Datasets

Project description:BACKGROUND:Breast cancer (BC) is highly heterogeneous with ~?60-70% of estrogen receptor positive BC patient's response to anti-hormone therapy. Estrogen receptors (ERs) play an important role in breast cancer progression and treatment. Estrogen related receptors (ERRs) are a group of nuclear receptors which belong to orphan nuclear receptors, which have sequence homology with ERs and share target genes. Here, we investigated the possible role and clinicopathological importance of ERR? in breast cancer. METHODS:Estrogen related receptor ? (ERR?) expression was examined using tissue microarray slides (TMA) of Breast Carcinoma patients with adjacent normal by immunohistochemistry and in breast cancer cell lines. In order to investigate whether ERR? is a direct target of ER?, we investigated the expression of ERR? in short hairpin ribonucleic acid knockdown of ER? breast cancer cells by western blot, qRT-PCR and RT-PCR. We further confirmed the binding of ER? by electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP), Re-ChIP and luciferase assays. Fluorescence-activated cell sorting analysis (FACS) was performed to elucidate the role of ERR? in cell cycle regulation. A Kaplan-Meier Survival analysis of GEO dataset was performed to correlate the expression of ERR? with survival in breast cancer patients. RESULTS:Tissue microarray (TMA) analysis showed that ERR? is significantly down-regulated in breast carcinoma tissue samples compared to adjacent normal. ER?+?ve breast tumors and cell lines showed a significant expression of ERR? compared to ER-ve tumors and cell lines. Estrogen treatment significantly induced the expression of ERR? and it was ER? dependent. Mechanistic analyses indicate that ER? directly targets ERR? through estrogen response element and ERR? also mediates cell cycle regulation through p18, p21cip and cyclin D1 in breast cancer cells. Our results also showed the up-regulation of ERR? promoter activity in ectopically co-expressed ER? and ERR? breast cancer cell lines. Fluorescence-activated cell sorting analysis (FACS) showed increased G0/G1 phase cell population in ERR? overexpressed MCF7 cells. Furthermore, ERR? expression was inversely correlated with overall survival in breast cancer. Collectively our results suggest cell cycle and tumor suppressor role of ERR? in breast cancer cells which provide a potential avenue to target ERR? signaling pathway in breast cancer. CONCLUSION:Our results indicate that ERR? is a negative regulator of cell cycle and a possible tumor suppressor in breast cancer. ERR? could be therapeutic target for the treatment of breast cancer.

Project description:Breast cancer resistance to the antiestrogens tamoxifen (OHT) and fulvestrant is accompanied by alterations in both estrogen-dependent and estrogen-independent signaling pathways. Consequently, effective inhibition of both pathways may be necessary to block proliferation of antiestrogen-resistant breast cancer cells. In this study, we examined the effects of apigenin, a dietary plant flavonoid with potential anticancer properties, on estrogen-responsive, antiestrogen-sensitive MCF7 breast cancer cells and two MCF7 sublines with acquired resistance to either OHT or fulvestrant. We found that apigenin can function as both an estrogen and an antiestrogen in a dose-dependent manner. At low concentrations (1 mumol/L), apigenin stimulated MCF7 cell growth but had no effect on the antiestrogen-resistant MCF7 sublines. In contrast, at high concentrations (>10 mumol/L), the drug inhibited growth of MCF7 cells and the antiestrogen-resistant sublines, and the combination of apigenin with either OHT or fulvestrant showed synergistic, growth-inhibitory effects on both antiestrogen-sensitive and antiestrogen-resistant breast cancer cells. To further elucidate the molecular mechanism of apigenin as either an estrogen or an antiestrogen, effects of the drug on estrogen receptor-alpha (ERalpha); transactivation activity, mobility, stability, and ERalpha-coactivator interactions were investigated. Low-dose apigenin enhanced receptor transcriptional activity by promoting interaction between ERalpha and its coactivator amplified in breast cancer-1. However, higher doses (>10 mumol/L) of apigenin inhibited ERalpha mobility (as determined by fluorescence recovery after photobleaching assays), down-regulated ERalpha and amplified in breast cancer-1 expression levels, and inhibited multiple protein kinases, including p38, protein kinase A, mitogen-activated protein kinase, and AKT. Collectively, these results show that apigenin can function as both an antiestrogen and a protein kinase inhibitor with activity against breast cancer cells with acquired resistance to OHT or fulvestrant. We conclude that apigenin, through its ability to target both ERalpha-dependent and ERalpha-independent pathways, holds promise as a new therapeutic agent against antiestrogen-resistant breast cancer.

Dataset Information

Effects of Benzophenone-3 and Propylparaben on Estrogen Receptor-Dependent R-Loops and DNA Damage in Breast Epithelial Cells and Mice.

Publications

Effects of Benzophenone-3 and Propylparaben on Estrogen Receptor-Dependent R-Loops and DNA Damage in Breast Epithelial Cells and Mice.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure