Membrane-bound estrogen receptor alpha initiated signaling is dynamin dependent in breast cancer cells

Abstract

BackgroundAlthough membrane-associated estrogen receptors (mERs) have been known to play important role in steroid-induced signal transmission, we still know little about their function in the estrogen-induced proliferation of breast cancer cells.MethodsIn our current work we tried to separate membrane-initiated estrogen receptor signaling from the overall estrogenic effect in MCF-7 breast carcinoma cells. Re-analyzing expression data from multiple microarray experiments, we selected a set of key regulatory genes involved in proliferation regulation and estrogen signaling to monitor estrogen-induced transcription changes. We then compared these expression changes after 17β-estradiol and a membrane receptor selective estrogen–BSA treatment using quantitative real-time PCR. In order to follow receptor trafficking we used light and electron microscopy.ResultsOur quantitative real-time PCR results confirmed that the selective membrane receptor agonist, estrogen–BSA induces similarly pronounced expression changes regarding these genes as 17β-estradiol. Morphological study revealed that the membrane-bound form of classical estrogen receptor alpha is internalized after ligand binding via dynamin-dependent, caveola-mediated endocytosis. Inhibition of this internalization with dynamin inhibitor, dynasore practically abolished the regulatory effect of E2-BSA, suggesting that interaction and internalization with the scaffold protein is necessary for effective signaling.ConclusionsThe physiological role of plasma membrane estrogen receptor alpha is intensively studied, yet there are still several aspects of it to be resolved. The dynamin-dependent, ligand-mediated internalization of mERs seems to play an important role in estrogen signaling. Our results may serve as another example of how membrane initiated estrogen signaling and nuclear receptor initiated signaling overlap and form an intertwined system. Electronic supplementary materialThe online version of this article (10.1186/s40001-018-0328-7) contains supplementary material, which is available to authorized users.

Investigation of cellular uptake mechanism of functionalised gold nanoparticles into breast cancer using SERS

“…43,44 Marczell et al have shown that the ERa pathway is linked to dynamin-dependent receptor endocytosis in MCF-7 cells. 45 Specically, immunoelectron microscopy imaging showed that membrane bound ERa undergoes ligand-mediated receptor internalisation via a dynamin-dependent pathway. 45 To demonstrate whether dynamin plays a role in ERa-AuNPs cellular uptake, MCF-7 cells were treated with dynasore, a GTPase inhibitor of dynamin.…”

“…45 Specically, immunoelectron microscopy imaging showed that membrane bound ERa undergoes ligand-mediated receptor internalisation via a dynamin-dependent pathway. 45 To demonstrate whether dynamin plays a role in ERa-AuNPs cellular uptake, MCF-7 cells were treated with dynasore, a GTPase inhibitor of dynamin. 46 The use of dynasore aimed to inform whether the inhibition of dynamin would disrupt the internalisation of ERa-AuNPs.…”

Isolation and Characterization of Phenylpropanoid and Lignan Compounds from Peperomia pellucida [L.] Kunth with Estrogenic Activities

“…stimulating PI3K/Akt and MAPK (mitogen-activated protein kinase) signaling intermediates [23][24][25]. The E-SCREEN assay and molecular docking studies were used to assess the estrogenic activity of samples and determined the mechanism for this through the characterization of the interaction with ERs.…”

“…The biological activities of estrogens are mediated by both genomic and non-genomic pathways [23][24][25]. Genomic effects are those involving the migration of estrogen-receptor complexes to the cell nucleus and direct interaction with chromatin at specific DNA sequences referred to as estrogen response elements (EREs).…”

“…On the other hand, non-genomic effects involve indirect regulation of gene expression through a variety of intracellular signaling events. In the non-genomic pathway, E 2 binds to ERs localized in the cell membrane and activates signal transduction pathways or functions via activation of the GPR30 signaling cascade, thus stimulating PI3K/Akt and MAPK (mitogen-activated protein kinase) signaling intermediates [23][24][25]. The E-SCREEN assay and molecular docking studies were used to assess the estrogenic activity of samples and determined the mechanism for this through the characterization of the interaction with ERs.…”