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Systems Biology of Metabolic Regulation by Estrogen Receptor Signaling in Breast Cancer
Published on: March 17, 2016
Estrogen receptor alpha rapidly activates the IGF-1 receptor pathway
S Kahlert1, S Nuedling, M van Eickels
1Medizinische Poliklinik and the Institut für Physiologie II, University of Bonn, 53111 Bonn, Germany.
The Journal of Biological Chemistry
|April 6, 2000
Summary
Estrogen receptor alpha (ERα) activation by estradiol rapidly triggers insulin-like growth factor 1 receptor (IGF-1R) signaling, unlike ERβ. This ERα-IGF-1R crosstalk is crucial for cellular proliferation control.
Area of Science:
- Cell Biology
- Endocrinology
- Molecular Signaling
Background:
- Estrogen and IGF-1 are key mitogens influencing cellular proliferation.
- The interaction between estrogen receptor (ER) and IGF-1 receptor (IGF-1R) signaling pathways remains unclear.
- ERα and ERβ exhibit distinct cellular functions and signaling mechanisms.
Purpose of the Study:
- To elucidate the coupling mechanisms between ERα/ERβ and IGF-1R signaling cascades.
- To investigate the role of ERα versus ERβ in mediating IGF-1R activation.
- To understand the contribution of ER signaling to IGF-1-induced cellular responses.
Main Methods:
- Selective transfection of ERα or ERβ in HEK293 and COS7 cells expressing IGF-1R.
- Assessment of IGF-1R and ERK1/2 phosphorylation following 17β-estradiol (E2) stimulation.
- Co-immunoprecipitation assays to detect ERα/ERβ binding to IGF-1R.
- Experiments using IGF-1R-deficient cell lines and dominant-negative MAPK inhibitors.
- Analysis of ER-responsive reporter gene activation (ERE-LUC) under IGF-1 stimulation.
Main Results:
- 17β-estradiol (E2) induced rapid IGF-1R and ERK1/2 phosphorylation specifically in the presence of ERα, not ERβ.
- Ligand-bound ERα, but not ERβ, directly bound to IGF-1R upon E2 stimulation in multiple cell lines.
- ERα binding to IGF-1R was confirmed in IGF-1R-deficient cells, indicating a direct interaction.
- Inhibition of MAPK signaling pathways attenuated E2-induced ERα-IGF-1R interactions.
- ERα, but not ERβ, was essential for activating an estrogen-responsive reporter in IGF-1-stimulated cells.
Conclusions:
- Ligand-bound ERα is a critical component for the rapid activation of the IGF-1R signaling cascade.
- ERα acts as a direct mediator, linking estrogen signaling to IGF-1R activation.
- These findings reveal a novel crosstalk mechanism between ERα and IGF-1R pathways essential for mitogenesis.
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