Estrogen and pure antiestrogen fulvestrant (ICI 182 780) augment cell-matrigel adhesion of MCF-7 breast cancer cells through a novel G protein coupled estrogen receptor (GPR30)-to-calpain signaling axis.

Abstract

Fulvestrant (ICI 182 780, ICI) has been used in treating patients with hormone-sensitive breast cancer, yet initial or acquired resistance to endocrine therapies frequently arises and, in particular, cancer recurs as metastasis. We demonstrate here that both 17-beta-estradiol (E2) and ICI enhance cell adhesion to matrigel in MCF-7 breast cancer cells, with increased autolysis of calpain 1 (large subunit) and proteolysis of focal adhesion kinase (FAK), indicating calpain activation. Additionally, either E2 or ICI induced down-regulation of estrogen receptor α without affecting G protein coupled estrogen receptor 30 (GPR30) expression. Interestingly, GPR30 agonist G1 triggered calpain 1 autolysis but not calpain 2, whereas ER agonist diethylstilbestrol caused no apparent calpain autolysis. Furthermore, the actions of E2 and ICI on calpain and cell adhesion were tremendously suppressed by G15, or knockdown of GPR30. E2 and ICI also induced phosphorylation of extracellular regulated protein kinases 1 and 2 (ERK1/2), and suppression of ERK1/2 phosphorylation by U0126 profoundly impeded calpain activation triggered by estrogenic and antiestrogenic stimulations indicating implication of ERK1/2 in the GPR30-mediated action. Lastly, the E2- or ICI-induced cell adhesion was dramatically impaired by calpain-specific inhibitors, ALLN or calpeptin, suggesting requirement of calpain in the GPR30-associated action. These data show that enhanced cell adhesion by E2 and ICI occurs via a novel GPR30-ERK1/2-calpain pathway. Our results indicate that targeting the GPR30 signaling may be a potential strategy to reduce metastasis and improve the efficacy of antiestrogens in treatment of advanced breast cancer.

• Authors: Yan Chen, Zheng Li, Yan He, Dandan Shang, Jigang Pan, Hongmei Wang, Huamei Chen, Zhuxia Zhu, Lei Wan, Xudong Wang
• Journal: Toxicology and applied pharmacology (Toxicol Appl Pharmacol) Vol. 275 Issue 2 Pg. 176-81 (Mar 01 2014) ISSN: 1096-0333 [Electronic] United States
• PMID: 24440569 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Inc. All rights reserved.

Chemical References

• Drug Combinations
• Estrogen Antagonists
• Estrogens
• GPER1 protein, human
• Laminin
• Proteoglycans
• Receptors, Estrogen
• Receptors, G-Protein-Coupled
• matrigel
• Fulvestrant
• Estradiol
• Collagen
• Calpain

Topics

• Breast Neoplasms (metabolism)
• Calpain (metabolism)
• Cell Adhesion (drug effects)
• Collagen (metabolism)
• Down-Regulation
• Drug Combinations
• Estradiol (analogs & derivatives, pharmacology)
• Estrogen Antagonists (pharmacology)
• Estrogens (metabolism)
• Female
• Fulvestrant
• Gene Silencing
• Humans
• Laminin (metabolism)
• MAP Kinase Signaling System
• MCF-7 Cells
• Phosphorylation
• Proteoglycans (metabolism)
• Receptors, Estrogen (genetics, metabolism)
• Receptors, G-Protein-Coupled (genetics, metabolism)
• Signal Transduction