Difficulty demonstrating estradiol-mediated Erk1/2 phosphorylation in MCF-7 cells

Brower, Stacey L.; Roberts, Jenny R.; Antonini, James M.; Miller, Michael R.

doi:10.1016/j.jsbmb.2005.05.006

Cited by 9 publications

(5 citation statements)

References 26 publications

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“…To reduce the interference of serum factors on the cell-killing effect of doxorubicin and to minimize the stress-response induced by complete removal of the serum factors [ 25 ], cell growth of MCF-7 cells in the presence of different concentrations of fetal bovine serum (FBS) was monitored using the MTT and trypan blue exclusion assays (data not shown). When the FBS concentration was reduced from 10% to 2%, there was no obvious change of cell growth.…”

Section: Resultsmentioning

confidence: 99%

7-ketocholesterol and 27-hydroxycholesterol decreased doxorubicin sensitivity in breast cancer cells: estrogenic activity and mTOR pathway

et al. 2017

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Hypercholesterolemia is one of the risk factors for poor outcome in breast cancer therapy. To elucidate the influence of the main circulating oxysterols, cholesterol oxidation products, on the cell-killing effect of doxorubicin, cells were exposed to oxysterols at a subtoxic concentration. When cells were exposed to oxysterols in fetal bovine serum-supplemented medium, 7-ketocholesterol (7-KC), but not 27-hydroxycholesterol (27-HC), decreased the cytotoxicity of doxorubicin in MCF-7 (high estrogen receptor (ER)α/ERβ ratio) cells and the decreased cytotoxicity was restored by the P-glycoprotein inhibitor verapamil. 7-KC stimulated the efflux function of P-glycoprotein and reduced intracellular doxorubicin accumulation in MCF-7 but not in ERα(-) MDA-MB-231 and the resistant MCF-7/ADR cells. In MCF-7 cells, 7-KC increased the mRNA and protein levels of P-glycoprotein. The 7-KC-suppressed doxorubicin accumulation was restored by the fluvestrant and ERα knockdown. In a yeast reporter assay, the ERα activation by 7-KC was more potent than 27-HC. 7-KC, but not 27-HC, stimulated the expression of an ER target, Trefoil factor 1 in MCF-7 cells. When charcoal-stripped fetal bovine serum was used, both 7-KC and 27-HC induced Trefoil factor 1 expression and reduced doxorubicin accumulation in MCF-7 cells. 7-KC-reduced doxorubicin accumulation could be reversed by inhibitors of phosphatidylinositol 3-kinase, Akt, and mammalian target of rapamycin (mTOR). These findings demonstrate that 7-KC decreases the cytotoxicity of doxorubicin through the up-regulation of P-glycoprotein in an ERα- and mTOR-dependent pathway. The 7-KC- and 27-HC-elicited estrogenic effects are crucial in the P-glycoprotein induction in breast cancer cells.

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Section: Resultsmentioning

confidence: 99%

7-ketocholesterol and 27-hydroxycholesterol decreased doxorubicin sensitivity in breast cancer cells: estrogenic activity and mTOR pathway

et al. 2017

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“…Similar observations were also reported by a number of other investigators (Bonapace et al, 1996; Joel et al, 1998; Lobenhofer and Marks, 2000; Lobenhofer et al, 2000; Caristi et al, 2001). Brower and colleagues attempted to address this problem by using a cell line from a laboratory which had reported positive responses (Filardo et al, 2000), but their result still turned out negative (Brower et al, 2005). Thus, it appears that the membrane ERα is non-functional in the MCF-7 cells used in the present study.…”

Section: Discussionmentioning

confidence: 99%

Requirement of ERα and basal activities of EGFR and Src kinase in Cd-induced activation of MAPK/ERK pathway in human breast cancer MCF-7 cells

Song

Wei

Shaikh

2015

Toxicology and Applied Pharmacology

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Cadmium (Cd) is a common environmental toxicant and an established carcinogen. Epidemiological studies implicate Cd with human breast cancer. Low micromolar concentrations of Cd promote proliferation of human breast cancer cells in vitro. The growth promotion of breast cancer cells is associated with the activation of MAPK/ERK pathway. This study explores the mechanism of Cd-induced activation of MAPK/ERK pathway. Specifically, the role of cell surface receptors ERα, EGFR, and Src kinase was evaluated in human breast cancer MCF-7 cells treated with 1–3 μM Cd. The activation of ERK was studied using a serum response element (SRE) luciferase reporter assay. Receptor phosphorylation was detected by Western blot analyses. Cd treatment increased both the SRE reporter activity and ERK1/2 phosphorylation in a concentration-dependent manner. Cd treatment had no effect on reactive oxygen species (ROS) generation. Also, blocking the entry of Cd into the cells with manganese did not diminish Cd-induced activation of MAPK/ERK. These results suggest that the effect of Cd was likely not caused by intracellular ROS generation, but through interaction with the membrane receptors. While Cd did not appear to activate either EGFR or Src kinase, their inhibition completely blocked the Cd-induced activation of ERK as well as cell proliferation. Similarly, silencing ERα with siRNA or use of ERα antagonist blocked the effects of Cd. Based on these results, it is concluded that not only ERα, but also basal activities of EGFR and Src kinase are essential for Cd-induced signal transduction and activation of MAPK/ERK pathway for breast cancer cell proliferation.

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“…None of the GPR30 agonists used, 17β-E 2 , ICI 182,780 or G-1, was able to induce Akt or ERK1/2 phosphorylation, at any of the time points tested (Figure 4). The lack of response to GPR30 agonists has been reported in other cell types (Brower, Roberts, Antonini, & Miller, 2005;Otto et al, 2008), including human breast cancer cell lines and BAEC. Unlike in cells where GPR30 was reported to be activated by 17β-E 2 , ICI 182,780 or G-1, in MCF-7 cells and BAEC, the GPR30 species of 44 and 50-55 kDa were undetectable, suggesting that those species are required for effective GPR30 signaling (Sousa et al, 2017).…”

Section: Discussionmentioning

confidence: 84%

Expression and function of the nonclassical estrogen receptor, GPR30, in human cartilage and chondrocytes

Ribeiro

Sousa

Rufino

et al. 2020

Journal Cellular Physiology

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Estrogen hormones are important for cartilage homeostasis, but nothing is known regarding the expression and role of the membrane G protein‐coupled estrogen receptor (GPER), G protein‐coupled receptor 30 (GPR30), in adult articular chondrocytes. Using immunohistochemistry of cartilage sections, quantitative real‐time polymerase chain reaction and Western blot of chondrocyte extracts, we found that these cells express GPR30. Nonetheless, the pattern of bands detected by two distinct antibodies does not overlap, suggesting that the proteins detected represent partially degraded forms of the receptor. Treatment with GPR30 agonists did not induce Akt or ERK1/2 phosphorylation, two known GPR30‐activated signaling pathways, suggesting that GPR30 is not functional in human chondrocytes. Therefore, the protective anti‐osteoarthritic role of estrogen hormones in cartilage homeostasis is likely independent of GPR30. This study was performed using human cartilage collected from the distal femoral condyles of multiorgan donors at the Bone and Tissue Bank of the University and Hospital Center of Coimbra.

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Difficulty demonstrating estradiol-mediated Erk1/2 phosphorylation in MCF-7 cells

Cited by 9 publications

References 26 publications

7-ketocholesterol and 27-hydroxycholesterol decreased doxorubicin sensitivity in breast cancer cells: estrogenic activity and mTOR pathway

7-ketocholesterol and 27-hydroxycholesterol decreased doxorubicin sensitivity in breast cancer cells: estrogenic activity and mTOR pathway

Requirement of ERα and basal activities of EGFR and Src kinase in Cd-induced activation of MAPK/ERK pathway in human breast cancer MCF-7 cells

Expression and function of the nonclassical estrogen receptor, GPR30, in human cartilage and chondrocytes

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