Affinity cytochemistry visualizes specific estrogen binding sites on the plasma membrane of breast cancer cells

1981 ◽  
Vol 14 (11) ◽  
pp. 1139-1146 ◽  
Author(s):  
Italo Nenci ◽  
Elisabetta Marchetti ◽  
Andrea Marzola ◽  
Guidalberto Fabris
Keyword(s):  
Breast Cancer ◽  
Plasma Membrane ◽  
Cancer Cells ◽  
Binding Sites ◽  
Breast Cancer Cells ◽  
Estrogen Binding

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.

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.

scholarly journals The interaction between endogenous calcineurin and the plasma membrane calcium-dependent ATPase is isoform specific in breast cancer cells

FEBS Letters ◽  
2007 ◽  
Vol 581 (21) ◽  
pp. 4115-4119 ◽  
Author(s):  
Marylouisa Holton ◽  
Di Yang ◽  
Weiguang Wang ◽  
Tamer M.A. Mohamed ◽  
Ludwig Neyses ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Plasma Membrane ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Calcium Dependent ◽  
Dependent Atpase

scholarly journals IFT20 Mediates the Transport of Cell Migration Regulators From the Trans-Golgi Network to the Plasma Membrane in Breast Cancer Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Huihui Yang ◽  
Fan Zhang ◽  
Huan Long ◽  
Yiwen Lin ◽  
Jiahui Liao ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Plasma Membrane ◽  
Cell Migration ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Intracellular Transport ◽  
Primary Cilia ◽  
Intraflagellar Transport ◽  
Trans Golgi Network ◽  
Golgi Network

IFT20 is a subunit of the intraflagellar transport (IFT) system essential for the formation and function of cilia. Besides predominant research in the cilia field, some IFT subunits perform extraciliary roles in non-ciliated cancer cells. However, the specific roles of IFT subunits in tumorigenesis remain unknown. Here, we found that knockout of IFT20 in mouse breast cancer cells lacking primary cilia promoted epithelial mesenchymal transitions (EMTs), active lamellipodia formation, and cell migration. IFT20 localized at the trans-Golgi and trans-Golgi network (TGN), and displayed vesicular co-distributions with Rab8a, the marker of TGN-to-plasma membrane vesicular trafficking. Proximity-dependent biotin identification (BioID) and colocalization analyzes showed that Numb and Ctnnal1, whose depletion promoted cell migration, co-localized with IFT20 at the trans-Golgi/TGN or intracellular transport vesicles. Furthermore, Strep-Tactin pulldown assays revealed an interaction between IFT20 and Ctnnal1 or Numb. Loss of IFT20 lowered the expression of actin-associated Tagln2, whose knockdown promoted cell migration. Thus, the extraciliary function of ITF20 in breast cancer cell was associated with the negative regulation of migration.

scholarly journals L1PA2 transposons contribute abundant regulatory sequences in MCF7 breast cancer cell line

2020 ◽  
Author(s):  
Jiayue-Clara Jiang ◽  
Joseph Rothnagel ◽  
Kyle Upton
Keyword(s):  
Breast Cancer ◽  
Transcription Factor ◽  
Cancer Cells ◽  
Binding Sites ◽  
Breast Cancer Cells ◽  
Transcription Factor Binding Sites ◽  
Transcription Factor Binding ◽  
Regulatory Sequences ◽  
Factor Binding ◽  
Regulatory Potential

ABSTRACTTransposons, a type of repetitive DNA elements, can contribute cis-regulatory sequences and regulate the expression of human genes. L1PA2 is a hominoid-specific subfamily of LINE1 transposons, with approximately 4,940 copies in the human genome. Individual transposons have been demonstrated to contribute specific biological functions, such as cancer-specific alternate promoter activity for the MET oncogene, which is correlated with enhanced malignancy and poor prognosis in cancer. Given the sequence similarity between L1PA2 elements, we hypothesise that transposons within the L1PA2 subfamily likely have a common regulatory potential and may provide a mechanism for global genome regulation. Here we show that in breast cancer, the regulatory potential of L1PA2 is not limited to single transposons, but is common within the subfamily. We demonstrate that the L1PA2 subfamily is an abundant reservoir of transcription factor binding sites, the majority of which cluster in the LINE1 5’UTR. In MCF7 breast cancer cells, over 27% of L1PA2 transposons harbour binding sites of functionally interacting, cancer-associated transcription factors. The ubiquitous and replicative nature of L1PA2 makes them an exemplary vector to disperse co-localised transcription factor binding sites, facilitating the co-ordinated regulation of genes. In MCF7 cells, L1PA2 transposons also supply transcription start sites to up-regulated transcripts. These transcriptionally active L1PA2 transposons display a cancer-specific active epigenetic profile, and likely play an oncogenic role in breast cancer aetiology. Overall, we show that the L1PA2 subfamily contributes abundant regulatory sequences in breast cancer cells, and likely plays a global role in modulating the tumorigenic state in breast cancer.

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