Limits...
Endocrine disruptor regulation of microRNA expression in breast carcinoma cells.

Tilghman SL, Bratton MR, Segar HC, Martin EC, Rhodes LV, Li M, McLachlan JA, Wiese TE, Nephew KP, Burow ME - PLoS ONE (2012)

Bottom Line: Given the important implications of EDC-regulated ER function, we sought to define the effects of BPA and DDT on microRNA regulation and expression levels in estrogen-responsive human breast cancer cells.To investigate the cellular effects of DDT and BPA, we used the human MCF-7 breast cancer cell line, which is ER (+) and hormone sensitive.Our results show that DDT and BPA potentiate ER transcriptional activity, resulting in an increased expression of receptor target genes, including progesterone receptor, bcl-2, and trefoil factor 1.

View Article: PubMed Central - PubMed

Affiliation: Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana, United States of America.

ABSTRACT

Background: Several environmental agents termed "endocrine disrupting compounds" or EDCs have been reported to bind and activate the estrogen receptor-α (ER). The EDCs DDT and BPA are ubiquitously present in the environment, and DDT and BPA levels in human blood and adipose tissue are detectable in most if not all women and men. ER-mediated biological responses can be regulated at numerous levels, including expression of coding RNAs (mRNAs) and more recently non-coding RNAs (ncRNAs). Of the ncRNAs, microRNAs have emerged as a target of estrogen signaling. Given the important implications of EDC-regulated ER function, we sought to define the effects of BPA and DDT on microRNA regulation and expression levels in estrogen-responsive human breast cancer cells.

Methodology/principal findings: To investigate the cellular effects of DDT and BPA, we used the human MCF-7 breast cancer cell line, which is ER (+) and hormone sensitive. Our results show that DDT and BPA potentiate ER transcriptional activity, resulting in an increased expression of receptor target genes, including progesterone receptor, bcl-2, and trefoil factor 1. Interestingly, a differential increase in expression of Jun and Fas by BPA but not DDT or estrogen was observed. In addition to ER responsive mRNAs, we investigated the ability of DDT and BPA to alter the miRNA profiles in MCF-7 cells. While the EDCs and estrogen similarly altered the expression of multiple microRNAs in MCF-7 cells, including miR-21, differential patterns of microRNA expression were induced by DDT and BPA compared to estrogen.

Conclusions/significance: We have shown, for the first time, that BPA and DDT, two well known EDCs, alter the expression profiles of microRNA in MCF-7 breast cancer cells. A better understanding of the molecular mechanisms of these compounds could provide important insight into the role of EDCs in human disease, including breast cancer.

Show MeSH

Related in: MedlinePlus

ERE-luciferase assay in MCF-7 cells.Cells were incubated overnight in media containing 5% charcoal-stripped FBS and were then transfected with an ERE-luciferase plasmid. After 4 hrs, drugs were added to the cells as indicated and luciferase levels were measured 18 hrs. later.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3293845&req=5

pone-0032754-g001: ERE-luciferase assay in MCF-7 cells.Cells were incubated overnight in media containing 5% charcoal-stripped FBS and were then transfected with an ERE-luciferase plasmid. After 4 hrs, drugs were added to the cells as indicated and luciferase levels were measured 18 hrs. later.

Mentions: To compare overall ERα transcriptional activity of two EDCs (DDT and BPA) with E2 treatment, ERE reporter assays in MCF-7 cells were performed. Results indicated an 8-fold increase in the activity of ERα in cells treated with ≥50 pM E2 (Figure 1A), in agreement with our and other groups previous studies [32], [33]. Interestingly, DDT and BPA both induced transcriptional activity of the ER; however, a full transcriptional response (i.e., comparable to E2) required higher concentrations of both agents compared to estrogen (Figure 1B and 1C). The E2, DDT, and BPA-induced transcriptional activity was suppressed by fulvestrant and tamoxifen with all treatments observed, as expected.


Endocrine disruptor regulation of microRNA expression in breast carcinoma cells.

Tilghman SL, Bratton MR, Segar HC, Martin EC, Rhodes LV, Li M, McLachlan JA, Wiese TE, Nephew KP, Burow ME - PLoS ONE (2012)

ERE-luciferase assay in MCF-7 cells.Cells were incubated overnight in media containing 5% charcoal-stripped FBS and were then transfected with an ERE-luciferase plasmid. After 4 hrs, drugs were added to the cells as indicated and luciferase levels were measured 18 hrs. later.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3293845&req=5

pone-0032754-g001: ERE-luciferase assay in MCF-7 cells.Cells were incubated overnight in media containing 5% charcoal-stripped FBS and were then transfected with an ERE-luciferase plasmid. After 4 hrs, drugs were added to the cells as indicated and luciferase levels were measured 18 hrs. later.
Mentions: To compare overall ERα transcriptional activity of two EDCs (DDT and BPA) with E2 treatment, ERE reporter assays in MCF-7 cells were performed. Results indicated an 8-fold increase in the activity of ERα in cells treated with ≥50 pM E2 (Figure 1A), in agreement with our and other groups previous studies [32], [33]. Interestingly, DDT and BPA both induced transcriptional activity of the ER; however, a full transcriptional response (i.e., comparable to E2) required higher concentrations of both agents compared to estrogen (Figure 1B and 1C). The E2, DDT, and BPA-induced transcriptional activity was suppressed by fulvestrant and tamoxifen with all treatments observed, as expected.

Bottom Line: Given the important implications of EDC-regulated ER function, we sought to define the effects of BPA and DDT on microRNA regulation and expression levels in estrogen-responsive human breast cancer cells.To investigate the cellular effects of DDT and BPA, we used the human MCF-7 breast cancer cell line, which is ER (+) and hormone sensitive.Our results show that DDT and BPA potentiate ER transcriptional activity, resulting in an increased expression of receptor target genes, including progesterone receptor, bcl-2, and trefoil factor 1.

View Article: PubMed Central - PubMed

Affiliation: Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana, United States of America.

ABSTRACT

Background: Several environmental agents termed "endocrine disrupting compounds" or EDCs have been reported to bind and activate the estrogen receptor-α (ER). The EDCs DDT and BPA are ubiquitously present in the environment, and DDT and BPA levels in human blood and adipose tissue are detectable in most if not all women and men. ER-mediated biological responses can be regulated at numerous levels, including expression of coding RNAs (mRNAs) and more recently non-coding RNAs (ncRNAs). Of the ncRNAs, microRNAs have emerged as a target of estrogen signaling. Given the important implications of EDC-regulated ER function, we sought to define the effects of BPA and DDT on microRNA regulation and expression levels in estrogen-responsive human breast cancer cells.

Methodology/principal findings: To investigate the cellular effects of DDT and BPA, we used the human MCF-7 breast cancer cell line, which is ER (+) and hormone sensitive. Our results show that DDT and BPA potentiate ER transcriptional activity, resulting in an increased expression of receptor target genes, including progesterone receptor, bcl-2, and trefoil factor 1. Interestingly, a differential increase in expression of Jun and Fas by BPA but not DDT or estrogen was observed. In addition to ER responsive mRNAs, we investigated the ability of DDT and BPA to alter the miRNA profiles in MCF-7 cells. While the EDCs and estrogen similarly altered the expression of multiple microRNAs in MCF-7 cells, including miR-21, differential patterns of microRNA expression were induced by DDT and BPA compared to estrogen.

Conclusions/significance: We have shown, for the first time, that BPA and DDT, two well known EDCs, alter the expression profiles of microRNA in MCF-7 breast cancer cells. A better understanding of the molecular mechanisms of these compounds could provide important insight into the role of EDCs in human disease, including breast cancer.

Show MeSH
Related in: MedlinePlus