Estrogen Induces Estrogen-related Receptor α Gene Expression and Chromatin Structural Changes in Estrogen Receptor (ER)-positive and ER-negative Breast Cancer Cells

Peng Hu,H Karimi Kinyamu,Liangli Wang,Jessica Martin,Trevor K Archer,Christina Teng

doi:10.1074/jbc.m705937200

Abstract

Estrogen-related receptor alpha (ERRalpha), a member of the nuclear receptor superfamily, is closely related to the estrogen receptors (ERalpha and ERbeta). The ERRalpha gene is estrogen-responsive in several mouse tissues and cell lines, and a multiple hormone-response element (MHRE) in the promoter is an important regulatory region for estrogen-induced ERRalpha gene expression. ERRalpha was recently shown to be a negative prognostic factor for breast cancer survival, with its expression being highest in cancer cells lacking functional ERalpha. The contribution of ERRalpha in breast cancer progression remains unknown but may have important clinical implications. In this study, we investigated ERRalpha gene expression and chromatin structural changes under the influence of 17beta-estradiol in both ER-positive MCF-7 and ER-negative SKBR3 breast cancer cells. We mapped the nucleosome positions of the ERRalpha promoter around the MHRE region and found that the MHRE resides within a single nucleosome. Local chromatin structure of the MHRE exhibited increased restriction enzyme hypersensitivity and enhanced histone H3 and H4 acetylation upon estrogen treatment. Interestingly, estrogen-induced chromatin structural changes could be repressed by estrogen antagonist ICI 182 780 in MCF-7 cells yet were enhanced in SKBR3 cells. We demonstrated, using chromatin immunoprecipitation assays, that 17beta-estradiol induces ERRalpha gene expression in MCF-7 cells through active recruitment of co-activators and release of co-repressors when ERRalpha and AP1 bind and ERalpha is tethered to the MHRE. We also found that this estrogen effect requires the MAPK signaling pathway in both cell lines.

Highlights

Estradiol (E2)2 is required for the development and function of multiple tissue types and physiological systems in mammals, In contrast to the ERs, the estrogen-related receptors (ERR) -␣, -␤, and -␥ all are orphan nuclear receptors with a high degree of sequence identity to the ERs but do not bind estrogens or any other known natural ligands [18, 19]
We demonstrated, using chromatin immunoprecipitation assays, that 17␤-estradiol induces ERR␣ gene expression in MCF-7 cells through active recruitment of co-activators and release of co-repressors when ERR␣ and AP1 bind and ER␣ is tethered to the multiple hormone-response element (MHRE)
The ERR␣ Gene MHRE Is Assembled Over a Single Nucleosome—We demonstrated previously that estrogen stimulation of the ERR␣ expression is mediated through the MHRE located between bp Ϫ709 to Ϫ649 of the ERR␣ promoter [51, 63]

Summary

Introduction

Estradiol (E2)2 is required for the development and function of multiple tissue types and physiological systems in mammals, In contrast to the ERs, the estrogen-related receptors (ERR) -␣, -␤, and -␥ all are orphan nuclear receptors with a high degree of sequence identity to the ERs but do not bind estrogens or any other known natural ligands [18, 19]. We demonstrated, using chromatin immunoprecipitation assays, that 17␤-estradiol induces ERR␣ gene expression in MCF-7 cells through active recruitment of co-activators and release of co-repressors when ERR␣ and AP1 bind and ER␣ is tethered to the MHRE. To map nucleosome positions from the 5Ј end of the 1-kb target region, nuclei from MCF-7 cells were digested with increasing concentrations of MNase; the DNA was purified, cut with StuI, blotted, and hybridized with probe A (Fig. 1B).

Results

Conclusion