Human Estrogen Receptor α Antagonists. Part 1: 3-D QSAR-Driven Rational Design of Innovative Coumarin-Related Antiestrogens as Breast Cancer Suppressants through Structure-Based and Ligand-Based Studies

2021 ◽  
Author(s):  
Nezrina Mihović ◽  
Nevena Tomašević ◽  
Sanja Matić ◽  
Marina M. Mitrović ◽  
Danijela A. Kostić ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Rational Design ◽  
Estrogen Receptor Α ◽  
Human Estrogen Receptor

scholarly journals The Human Estrogen Receptor-α Isoform hERα46 Antagonizes the Proliferative Influence of hERα66 in MCF7 Breast Cancer Cells

Endocrinology ◽  
2005 ◽  
Vol 146 (12) ◽  
pp. 5474-5484 ◽  
Author(s):  
Graziella Penot ◽  
Christine Le Péron ◽  
Yohann Mérot ◽  
Eva Grimaud-Fanouillère ◽  
François Ferrière ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Estrogen Receptor ◽  
Cell Growth ◽  
Activation Function ◽  
Estrogen Receptor Α ◽  
Breast Cancer Cell Lines ◽  
Mcf7 Cells ◽  
Exact Function ◽  
Human Estrogen Receptor

The expression of two human estrogen receptor-α (hERα) isoforms has been characterized within estrogen receptor-α-positive breast cancer cell lines such as MCF7: the full-length hERα66 and the N terminally deleted hERα46, which is devoid of activation function (AF)-1. Although hERα66 is known to mediate the mitogenic effects that estrogens have on MCF7 cells, the exact function of hERα46 in these cells remains undefined. Here we show that, during MCF7 cell growth, hERα46 is mainly expressed in the nucleus at relatively low levels, whereas hERα66 accumulates in the nucleus. When cells reach confluence, the situation reverses, with hERα46 accumulating within the nucleus. Although hERα46 expression remains rather stable during an estrogen-induced cell cycle, its overexpression in proliferating MCF7 cells provokes a cell-cycle arrest in G0/G1 phases. To gain further details on the influence of hERα46 on cell growth, we used PC12 estrogen receptor-α-negative cell line, in which stable transfection of hERα66 but not hERα46 allows estrogens to behave as mitogens. We next demonstrate that, in MCF7 cells, overexpression of hERα46 inhibits the hERα66-mediated estrogenic induction of all AF-1-sensitive reporters: c-fos and cyclin D1 as well as estrogen-responsive element-driven reporters. Our data indicate that this inhibition occurs likely through functional competitions between both isoforms. In summary, hERα46 antagonizes the proliferative action of hERα66 in MCF7 cells in part by inhibiting hERα66 AF-1 activity.

scholarly journals The Peptide ERα17p Is a GPER Inverse Agonist that Exerts Antiproliferative Effects in Breast Cancer Cells

Cells ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 590 ◽  
Author(s):  
Rosamaria Lappano ◽  
Christophe Mallet ◽  
Bruno Rizzuti ◽  
Fedora Grande ◽  
Giulia Galli ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Growth Factor Receptor ◽  
Estrogen Receptor Α ◽  
Inverse Agonist ◽  
Extracellular Signal ◽  
Human Estrogen Receptor ◽  
Epidermal Growth

The inhibition of the G protein-coupled estrogen receptor (GPER) offers promising perspectives for the treatment of breast tumors. A peptide corresponding to part of the hinge region/AF2 domain of the human estrogen receptor α (ERα17p, residues 295–311) exerts anti-proliferative effects in various breast cancer cells including those used as triple negative breast cancer (TNBC) models. As preliminary investigations have evoked a role for the GPER in the mechanism of action of this peptide, we focused our studies on this protein using SkBr3 breast cancer cells, which are ideal for GPER evaluation. ERα17p inhibits cell growth by targeting membrane signaling. Identified as a GPER inverse agonist, it co-localizes with GPER and induces the proteasome-dependent downregulation of GPER. It also decreases the level of pEGFR (phosphorylation of epidermal growth factor receptor), pERK1/2 (phosphorylation of extracellular signal-regulated kinase), and c-fos. ERα17p is rapidly distributed in mice after intra-peritoneal injection and is found primarily in the mammary glands. The N-terminal PLMI motif, which presents analogies with the GPER antagonist PBX1, reproduces the effect of the whole ERα17p. Thus, this motif seems to direct the action of the entire peptide, as highlighted by docking and molecular dynamics studies. Consequently, the tetrapeptide PLMI, which can be claimed as the first peptidic GPER disruptor, could open new avenues for specific GPER modulators.

scholarly journals Direct Visualization of the Human Estrogen Receptor α Reveals a Role for Ligand in the Nuclear Distribution of the Receptor

1999 ◽  
Vol 10 (2) ◽  
pp. 471-486 ◽  
Author(s):  
Han Htun ◽  
Laurel T. Holth ◽  
Dawn Walker ◽  
James R. Davie ◽  
Gordon L. Hager
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Epithelial Cell ◽  
Cell Lines ◽  
Human Breast Cancer ◽  
Estrogen Receptor Α ◽  
Human Breast ◽  
Epithelial Cell Lines ◽  
Human Estrogen Receptor ◽  
Breast Cancer Epithelial Cell

The human estrogen receptor α (ER α) has been tagged at its amino terminus with the S65T variant of the green fluorescent protein (GFP), allowing subcellular trafficking and localization to be observed in living cells by fluorescence microscopy. The tagged receptor, GFP-ER, is functional as a ligand-dependent transcription factor, responds to both agonist and antagonist ligands, and can associate with the nuclear matrix. Its cellular localization was analyzed in four human breast cancer epithelial cell lines, two ER+ (MCF7 and T47D) and two ER− (MDA-MB-231 and MDA-MB-435A), under a variety of ligand conditions. In all cell lines, GFP-ER is observed only in the nucleus in the absence of ligand. Upon the addition of agonist or antagonist ligand, a dramatic redistribution of GFP-ER from a reticular to punctate pattern occurs within the nucleus. In addition, the full antagonist ICI 182780 alters the nucleocytoplasmic compartmentalization of the receptor and causes partial accumulation in the cytoplasm in a process requiring continued protein synthesis. GFP-ER localization varies between cells, despite being cultured and treated in a similar manner. Analysis of the nuclear fluorescence intensity for variation in its frequency distribution helped establish localization patterns characteristic of cell line and ligand. During the course of this study, localization of GFP-ER to the nucleolar region is observed for ER− but not ER+ human breast cancer epithelial cell lines. Finally, our work provides a visual description of the “unoccupied” and ligand-bound receptor and is discussed in the context of the role of ligand in modulating receptor activity.

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