Pentagalloylglucose inhibits estrogen receptor α by lysosome-dependent depletion and modulates ErbB/PI3K/Akt pathway in human breast cancer MCF-7 cells

2006 ◽  
Vol 45 (8) ◽  
pp. 551-560 ◽  
Author(s):  
Kuo-Tai Hua ◽  
Tzong-Der Way ◽  
Jen-Kun Lin
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Human Breast Cancer ◽  
Estrogen Receptor Α ◽  
Akt Pathway ◽  
Human Breast ◽  
Mcf 7

scholarly journals Various Phosphorylation Pathways, Depending on Agonist and Antagonist Binding to Endogenous Estrogen Receptor α (ERα), Differentially Affect ERα Extractability, Proteasome-Mediated Stability, and Transcriptional Activity in Human Breast Cancer Cells

2003 ◽  
Vol 17 (10) ◽  
pp. 2013-2027 ◽  
Author(s):  
Véronique Marsaud ◽  
Angélique Gougelet ◽  
Sébastien Maillard ◽  
Jack-Michel Renoir
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Protein Kinase ◽  
Human Breast Cancer ◽  
Breast Cancer Cells ◽  
Kinase Inhibitors ◽  
Estrogen Receptor Α ◽  
Human Breast ◽  
Ligand Free ◽  
Mcf 7

Abstract Estrogen receptor-α (ER) is down-regulated in the presence of its cognate ligand, estradiol (E2), as well as in the presence of antiestrogens, through the ubiquitin proteasome pathway. Here, we show that, at pharmacological concentrations, the degradation rate of pure antagonist/endogenous ER complexes from human breast cancer MCF-7 cells is 10 times faster than that of ER-E2 complexes, while 4-hydroxy-tamoxifen (4-OH-T)-ER complexes are stable. Whereas pure antagonist-ER complexes are firmly bound to a nuclear compartment from which they are not extractable, the 4-OH-T-ER accumulates in a soluble cell compartment. No difference was observed in the fate of ER whether bound to pure antiestrogens ICI 182,780 or RU 58668. Cycloheximide experiments showed that, while the proteasome-mediated destruction of E2-ER (unlike that of RU 58668- and ICI 182,780-ER) complexes could implicate (or not) a protein synthesis-dependent process, both MAPKs (p38 and ERKs p44 and p42) are activated. By using a panel of kinase inhibitors/activators to study the impact of phosphorylation pathways on ER degradation, we found that protein kinase C is an enhancer of proteasome-mediated degradation of both ligand-free and ER bound to either E2, 4-OH-T, and pure antagonists. On the contrary, protein kinase A, MAPKs, and phosphatidyl-inositol-3 kinase all impede proteasome-mediated destruction of ligand free and E2-bound ER while only MAPKs inhibit the degradation of pure antiestrogens/ER species. In addition, no correlation was found between the capacity of kinase inhibitors to affect ER stability and the basal or E2-induced transcription. These results suggest that, in MCF-7 breast cancer cells, ER turnover, localization, and activity are maintained by an equilibrium between various phosphorylation pathways, which are differently modulated by ER ligands and protein kinases.

scholarly journals O-GlcNAcylation-Inducing Treatments Inhibit Estrogen Receptor α Expression and Confer Resistance to 4-OH-Tamoxifen in Human Breast Cancer-Derived MCF-7 Cells

PLoS ONE ◽  
2013 ◽  
Vol 8 (7) ◽  
pp. e69150 ◽  
Author(s):  
Shahzina Kanwal ◽  
Yann Fardini ◽  
Patrick Pagesy ◽  
Thierry N’Tumba-Byn ◽  
Cécile Pierre-Eugène ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Human Breast Cancer ◽  
Estrogen Receptor Α ◽  
Human Breast ◽  
Mcf 7

Down-regulation of estrogen receptor-α in MCF-7 human breast cancer cells after proteasome inhibition

2006 ◽  
Vol 72 (5) ◽  
pp. 566-572 ◽  
Author(s):  
Kannan V. Balan ◽  
Yongbao Wang ◽  
Siming W. Chen ◽  
Panayotis Pantazis ◽  
James H. Wyche ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Human Breast Cancer ◽  
Breast Cancer Cells ◽  
Proteasome Inhibition ◽  
Estrogen Receptor Α ◽  
Human Breast Cancer Cells ◽  
Human Breast ◽  
Mcf 7

scholarly journals Thioredoxin and thioredoxin reductase influence estrogen receptor α-mediated gene expression in human breast cancer cells

2009 ◽  
Vol 43 (6) ◽  
pp. 251-261 ◽  
Author(s):  
Abhi K Rao ◽  
Yvonne S Ziegler ◽  
Ian X McLeod ◽  
John R Yates ◽  
Ann M Nardulli
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Estrogen Receptor ◽  
Antioxidant Enzymes ◽  
Human Breast Cancer ◽  
Breast Cancer Cells ◽  
Estrogen Receptor Α ◽  
Human Breast Cancer Cells ◽  
Human Breast ◽  
Mcf 7

Accumulation of reactive oxygen species (ROS) in cells damages resident proteins, lipids, and DNA. In order to overcome the oxidative stress that occurs with ROS accumulation, cells must balance free radical production with an increase in the level of antioxidant enzymes that convert free radicals to less harmful species. We identified two antioxidant enzymes, thioredoxin (Trx) and Trx reductase (TrxR), in a complex associated with the DNA-bound estrogen receptor α (ERα). Western analysis and immunocytochemistry were used to demonstrate that Trx and TrxR are expressed in the cytoplasm and in the nuclei of MCF-7 human breast cancer cells. More importantly, endogenously expressed ERα, Trx, and TrxR interact and ERα and TrxR associate with the native, estrogen-responsive pS2 and progesterone receptor genes in MCF-7 cells. RNA interference assays demonstrated that Trx and TrxR differentially influence estrogen-responsive gene expression and that together, 17β-estradiol, Trx, and TrxR alter hydrogen peroxide (H2O2) levels in MCF-7 cells. Our findings suggest that Trx and TrxR are multifunctional proteins that, in addition to modulating H2O2 levels and transcription factor activity, aid ERα in regulating the expression of estrogen-responsive genes in target cells.

scholarly journals Cooperative Coactivation of Estrogen Receptor α in ZR-75 Human Breast Cancer Cells by SNURF and TATA-binding Protein

2001 ◽  
Vol 277 (4) ◽  
pp. 2485-2497 ◽  
Author(s):  
Bradley Saville ◽  
Hetti Poukka ◽  
Mark Wormke ◽  
Olli A. Jänne ◽  
Jorma J. Palvimo ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Human Breast Cancer ◽  
Breast Cancer Cells ◽  
Binding Protein ◽  
Estrogen Receptor Α ◽  
Tata Binding Protein ◽  
Human Breast Cancer Cells ◽  
Human Breast
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