scholarly journals EGFR Expression in HER2-Driven Breast Cancer Cells

2020 ◽  
Vol 21 (23) ◽  
pp. 9008
Author(s):  
Florian Weinberg ◽  
Diana B. Peckys ◽  
Niels de Jonge
Keyword(s):  
Breast Cancer ◽  
Electron Microscopy ◽  
Plasma Membrane ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Simultaneous Detection ◽  
Orphan Receptor ◽  
Membrane Expression ◽  
Intact Cells ◽  
Egfr Expression

The epidermal growth factor receptor HER2 is overexpressed in 20% of breast cancer cases. HER2 is an orphan receptor that is activated ligand-independently by homodimerization. In addition, HER2 is able to heterodimerize with EGFR, HER3, and HER4. Heterodimerization has been proposed as a mechanism of resistance to therapy for HER2 overexpressing breast cancer. Here, a method is presented for the simultaneous detection of individual EGFR and HER2 receptors in the plasma membrane of breast cancer cells via specific labeling with quantum dot nanoparticles (QDs). Correlative fluorescence microscopy and liquid phase electron microscopy were used to analyze the plasma membrane expression levels of both receptors in individual intact cells. Fluorescent single-cell analysis of SKBR3 breast cancer cells dual-labeled for EGFR and HER2 revealed a heterogeneous expression for receptors within both the cell population as well as within individual cells. Subsequent electron microscopy of individual cells allowed the determination of individual receptors label distributions. QD-labeled EGFR was observed with a surface density of (0.5–5) × 101 QDs/µm2, whereas labeled HER2 expression was higher ranging from (2–10) × 102 QDs/µm2. Although most SKBR3 cells expressed low levels of EGFR, an enrichment was observed at large plasma membrane protrusions, and amongst a newly discovered cellular subpopulation termed EGFR-enriched cells.

scholarly journals EHD2 is a mechanotransducer connecting caveolae dynamics with gene transcription

2018 ◽  
Vol 217 (12) ◽  
pp. 4092-4105 ◽  
Author(s):  
Stéphanie Torrino ◽  
Wei-Wei Shen ◽  
Cédric M. Blouin ◽  
Satish Kailasam Mani ◽  
Christine Viaris de Lesegno ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Electron Microscopy ◽  
Gene Regulation ◽  
Plasma Membrane ◽  
Cancer Cells ◽  
Mechanical Stress ◽  
Gene Transcription ◽  
Breast Cancer Cells ◽  
Membrane Tension

Caveolae are small invaginated pits that function as dynamic mechanosensors to buffer tension variations at the plasma membrane. Here we show that under mechanical stress, the EHD2 ATPase is rapidly released from caveolae, SUMOylated, and translocated to the nucleus, where it regulates the transcription of several genes including those coding for caveolae constituents. We also found that EHD2 is required to maintain the caveolae reservoir at the plasma membrane during the variations of membrane tension induced by mechanical stress. Metal-replica electron microscopy of breast cancer cells lacking EHD2 revealed a complete absence of caveolae and a lack of gene regulation under mechanical stress. Expressing EHD2 was sufficient to restore both functions in these cells. Our findings therefore define EHD2 as a central player in mechanotransduction connecting the disassembly of the caveolae reservoir with the regulation of gene transcription under mechanical stress.

scholarly journals Quantification of EGFR-HER2 Heterodimers in HER2-Overexpressing Breast Cancer Cells Using Liquid-Phase Electron Microscopy

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3244
Author(s):  
Diana B. Peckys ◽  
Daniel Gaa ◽  
Niels de Jonge
Keyword(s):  
Breast Cancer ◽  
Electron Microscopy ◽  
Epidermal Growth Factor Receptor ◽  
Plasma Membrane ◽  
Liquid Phase ◽  
Growth Factor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Growth Factor Receptor ◽  
Epidermal Growth

Currently, breast cancer patients are classified uniquely according to the expression level of hormone receptors, and human epidermal growth factor receptor 2 (HER2). This coarse classification is insufficient to capture the phenotypic complexity and heterogeneity of the disease. A methodology was developed for absolute quantification of receptor surface density ρR, and molecular interaction (dimerization), as well as the associated heterogeneities, of HER2 and its family member, the epidermal growth factor receptor (EGFR) in the plasma membrane of HER2 overexpressing breast cancer cells. Quantitative, correlative light microscopy (LM) and liquid-phase electron microscopy (LPEM) were combined with quantum dot (QD) labeling. Single-molecule position data of receptors were obtained from scanning transmission electron microscopy (STEM) images of intact cancer cells. Over 280,000 receptor positions were detected and statistically analyzed. An important finding was the subcellular heterogeneity in heterodimer shares with respect to plasma membrane regions with different dynamic properties. Deriving quantitative information about EGFR and HER2 ρR, as well as their dimer percentages, and the heterogeneities thereof, in single cancer cells, is potentially relevant for early identification of patients with HER2 overexpressing tumors comprising an enhanced share of EGFR dimers, likely increasing the risk for drug resistance, and thus requiring additional targeted therapeutic strategies.

scholarly journals Glycosylation Modulates Plasma Membrane Trafficking of CD24 in Breast Cancer Cells

2021 ◽  
Vol 22 (15) ◽  
pp. 8165
Author(s):  
Amanda Chantziou ◽  
Kostas Theodorakis ◽  
Hara Polioudaki ◽  
Eelco de Bree ◽  
Marilena Kampa ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Plasma Membrane ◽  
Subcellular Localization ◽  
Cancer Cells ◽  
Membrane Trafficking ◽  
Breast Cancer Cells ◽  
Endocytic Pathway ◽  
Cell Periphery ◽  
Wild Type ◽  
Mcf 7

In breast cancer, expression of Cluster of Differentiation 24 (CD24), a small GPI-anchored glycoprotein at the cell periphery, is associated with metastasis and immune escape, while its absence is associated with tumor-initiating capacity. Since the mechanism of CD24 sorting is unknown, we investigated the role of glycosylation in the subcellular localization of CD24. Expression and localization of wild type N36- and/or N52-mutated CD24 were analyzed using immunofluorescence in luminal (MCF-7) and basal B (MDA-MB-231 and Hs578T) breast cancer cells lines, as well as HEK293T cells. Endogenous and exogenously expressed wild type and mutated CD24 were found localized at the plasma membrane and the cytoplasm, but not the nucleoplasm. The cell lines showed different kinetics for the sorting of CD24 through the secretory/endocytic pathway. N-glycosylation, especially at N52, and its processing in the Golgi were critical for the sorting and expression of CD24 at the plasma membrane of HEK293T and basal B type cells, but not of MCF-7 cells. In conclusion, our study highlights the contribution of N-glycosylation for the subcellular localization of CD24. Aberrant N-glycosylation at N52 of CD24 could account for the lack of CD24 expression at the cell surface of basal B breast cancer cells.

scholarly journals Whole-cell uptake and nuclear localization of 1,25-dihydroxycholecalciferol by breast cancer cells (T47 D) in culture

1981 ◽  
Vol 200 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Elizabeth Sher ◽  
John A. Eisman ◽  
Jane M. Moseley ◽  
T. John Martin
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Binding Sites ◽  
Breast Cancer Cells ◽  
Nuclear Translocation ◽  
Vitamin D Metabolites ◽  
Intact Cells ◽  
Cells In Culture

Specific high-affinity receptors for 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] have been described recently in broken-cell preparations of several cultured human breast cancer cell lines including the T47 D line. It was necessary to determine whether intact breast cancer cells in culture would bind 1,25-(OH)2D3 specifically and whether the next step in the proposed scheme of action, i.e. nuclear translocation, occurred. The following results were obtained. (1) Specific uptake of 1,25-(OH)2D3 by T47 D cells occurs in intact cells in culture. (2) The rate of uptake is proportional to medium 1,25-(OH)2D3 concentration but is slow compared with that of other steroid hormones, e.g., oestradiol, under identical conditions. Even at 0.5nm-1,25-(OH)2D3 in the medium, at least 4h are required to reach maximum compared with less than 1h for oestradiol binding. (3) Estimation of binding characteristics by Scatchard analysis indicates a single class of binding sites with Kd of 68pm and 11800 binding sites/cell, which are similar results to those obtained with broken-cell preparations. (4) Inclusion of various vitamin D metabolites in the incubation medium decreased specific binding of 1,25-(OH)2D3 by the intact cells in a manner identical with their effects in the broken-cell preparation and with potencies similar to their potency on Ca2+ transport and bone resorption in vivo. Order of potency was 1,25-(OH)2D3>(24R)-1,24,25-trihydroxycholecalciferol »25-hydroxycholecalciferol>(25R)-24,25-dihydroxycholecalciferol »(25R)-25,26-dihydroxycholecalciferol. (5) In the 1,25-(OH)2D3-depleted state, 80% of the 1,25(OH)2D3 receptor is found in the cytosol fraction of the cells even when the subcellular fractionation is performed under low-salt conditions. By contrast after incubation with [3H]1,25-(OH)2D3, 59% of the specific 1,25-(OH)2D3 binding is found in the partially purified nuclei fraction. These data indicate that nuclear translocation of the receptor–hormone complex takes place in the intact T47 D cell. The results also support the hypothesis that the 1,25-(OH)2D3 receptor is functional in this cultured breast cancer cell line, which may provide a useful model for further study of the early biochemical events in 1,25-(OH)2D3 action.

Cxcl10 chemokine induces migration of ING4-deficient breast cancer cells via a novel crosstalk mechanism between the Cxcr3 and Egfr receptors

2021 ◽  
Author(s):  
Emily Tsutsumi ◽  
Jeremiah Stricklin ◽  
Emily A. Peterson ◽  
Joyce A. Schroeder ◽  
Suwon Kim
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Breast Cancer Cells ◽  
Critical Role ◽  
Disease Free Survival ◽  
Intact Cells ◽  
Free Survival ◽  
Egfr Receptors

The chemokine Cxcl10 has been associated with poor prognosis in breast cancer, but the mechanism is not well understood. Our previous study have shown that CXCL10 was repressed by the ING4 tumor suppressor, suggesting a potential inverse functional relationship. We thus investigated a role for Cxcl10 in the context of ING4 deficiencies in breast cancer. We first analyzed public gene expression datasets and found that patients with CXCL10 -high/ ING4 -low expressing tumors had significantly reduced disease-free survival in breast cancer. In vitro , Cxcl10 induced migration of ING4 -deleted breast cancer cells, but not of ING4 -intact cells. Using inhibitors, we found that Cxcl10-induced migration of ING4 -deleted cells required Cxcr3, Egfr, and the Gβγ subunits downstream of Cxcr3, but not Gαi. Immunofluorescent imaging showed that Cxcl10 induced early transient colocalization between Cxcr3 and Egfr in both ING4 -intact and ING4 -deleted cells, which recurred only in ING4 -deleted cells. A peptide agent that binds to the internal juxtamembrane domain of Egfr inhibited Cxcr3/Egfr colocalization and cell migration. Taken together, these results presented a novel mechanism of Cxcl10 that elicits migration of ING4 -deleted cells, in part by inducing a physical or proximal association between Cxcr3 and Egfr and signaling downstream via Gβγ. These results further indicated that ING4 plays a critical role in the regulation of Cxcl10 signaling that enables breast cancer progression.

scholarly journals Interaction of the Anti-Proliferative GPER Inverse Agonist ERα17p with the Breast Cancer Cell Plasma Membrane: From Biophysics to Biology

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 447 ◽  
Author(s):  
Michaël Trichet ◽  
Rosamaria Lappano ◽  
Mathilde Belnou ◽  
Lilian Salazar Vazquez ◽  
Isabel Alves ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Plasma Membrane ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Breast Cancer Cells ◽  
Direct Interaction ◽  
Lipid Vesicles ◽  
Estrogen Receptor Α ◽  
Cd Spectroscopy

The peptide ERα17p, which corresponds to the 295-311 fragment of the hinge/AF2 domains of the human estrogen receptor α (ERα), exerts apoptosis in breast cancer cells through a mechanism involving the G protein-coupled estrogen-dependent receptor GPER. Besides this receptor-mediated mechanism, we have detected a direct interaction (Kd value in the micromolar range) of this peptide with lipid vesicles mimicking the plasma membrane of eukaryotes. The reversible and not reversible pools of interacting peptide may correspond to soluble and aggregated membrane-interacting peptide populations, respectively. By using circular dichroism (CD) spectroscopy, we have shown that the interaction of the peptide with this membrane model was associated with its folding into β sheet. A slight leakage of the 5(6)-fluorescein was also observed, indicating lipid bilayer permeability. When the peptide was incubated with living breast cancer cells at the active concentration of 10 μM, aggregates were detected at the plasma membrane under the form of spheres. This insoluble pool of peptide, which seems to result from a fibrillation process, is internalized in micrometric vacuoles under the form of fibrils, without evidence of cytotoxicity, at least at the microscopic level. This study provides new information on the interaction of ERα17p with breast cancer cell membranes as well as on its mechanism of action, with respect to direct membrane effects.

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