Pharmacological Inhibition of MCT4 Reduces 4-Hydroxytamoxifen Sensitivity by Increasing HIF-1α Protein Expression in ER-Positive MCF-7 Breast Cancer Cells

Abstract Background The mechanisms of endocrine resistance are complex, and deregulation of several oncogenic signalling pathways has been proposed. We aimed to investigate the role of the EGFR and Src-mediated STAT3 signalling pathway in tamoxifen-resistant breast cancer cells. Methods The ER-positive luminal breast cancer cell lines, MCF-7 and T47D, were used. We have established an MCF-7-derived tamoxifen-resistant cell line (TamR) by long-term culture of MCF-7 cells with 4-hydroxytamoxifen. Cell viability was determined using an MTT assay, and protein expression levels were determined using western blot. Cell cycle and annexin V staining were analysed using flow cytometry. Results TamR cells showed decreased expression of estrogen receptor and increased expression of EGFR. TamR cells showed an acceleration of the G1 to S phase transition. The protein expression levels of phosphorylated Src, EGFR (Y845), and STAT3 was increased in TamR cells, while phosphorylated Akt was decreased. The expression of p-STAT3 was enhanced according to exposure time of tamoxifen in T47D cells, suggesting that activation of STAT3 can cause tamoxifen resistance in ER-positive breast cancer cells. Both dasatinib (Src inhibitor) and stattic (STAT3 inhibitor) inhibited cell proliferation and induced apoptosis in TamR cells. However, stattic showed a much stronger effect than dasatinib. Knockdown of STAT3 expression by siRNA had no effect on sensitivity to tamoxifen in MCF-7 cells, while that enhanced sensitivity to tamoxifen in TamR cells. There was not a significant synergistic effect of dasatinib and stattic on cell survival. TamR cells have low nuclear p21(Cip1) expression compared to MCF-7 cells and inhibition of STAT3 increased the expression of nuclear p21(Cip1) in TamR cells. Conclusions The EGFR and Src-mediated STAT3 signalling pathway is activated in TamR cells, and inhibition of STAT3 may be a potential target in tamoxifen-resistant breast cancer. An increase in nuclear p21(Cip1) may be a key step in STAT3 inhibitor-induced cell death in TamR cells.

Download Full-text

Paeoniflorin Enhances the Sensitivity of ER-Positive Breast Cancer Cells to Tamoxifen through Promoting Sirtuin 4

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2022/6730559 ◽

2022 ◽

Vol 2022 ◽

pp. 1-11

Author(s):

Pei Zhang ◽

Nan Wu ◽

Zhi-Jun Song ◽

Zheng-Fu Tai

Keyword(s):

Breast Cancer ◽

Cell Proliferation ◽

Protein Expression ◽

Cancer Cells ◽

Cell Lines ◽

Breast Cancer Cells ◽

Expression Ratio ◽

Er Positive ◽

Mcf 7 ◽

Positive Breast Cancer

Tamoxifen is an effective drug for treating patients with advanced estrogen receptor-positive (ER+) breast cancer (BC), but not for all ER + BC patients. Drug tolerance is the biggest obstacle. In this study, we designed an experiment to investigate whether paeoniflorin affects the ER + BC cell’s sensitivity to tamoxifen in the T47D and MCF-7 cell lines. Herein, we found that paeoniflorin inhibited cell proliferation without inducing apoptosis. However, it enhanced tamoxifen-induced apoptosis in both cell lines. Immunoblotting revealed that paeoniflorin significantly increased the already elevated Bax/Bcl2 protein expression ratio and the caspase 3 activity levels, both induced by tamoxifen. Paeoniflorin was also found to increase SIRT4 expression, and deletion of SIRT4 could significantly reverse the inhibition of cell proliferation induced by paeoniflorin and significantly decrease paeoniflorin-enhanced apoptosis induced by tamoxifen. Moreover, protein expression detection revealed that paeoniflorin enhanced the tamoxifen-induced inhibition of STAT3 activation. Besides, the deletion of SIRT4 could significantly increase STAT3 activation in the T47D and MCF-7 cells. In conclusion, paeoniflorin suppressed STAT3 activation to enhance the sensitivity of ER-positive breast cancer cells to tamoxifen through promoting SIRT4 expression.

Download Full-text

In vitro evaluation of estrogenic, antiestrogenic and antitumor effects of amentoflavone

Human & Experimental Toxicology ◽

10.1177/0960327121999454 ◽

2021 ◽

pp. 096032712199945

Author(s):

AT Aliyev ◽

S Ozcan-Sezer ◽

A Akdemir ◽

H Gurer-Orhan

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Antitumor Effects ◽

Antiestrogenic Activity ◽

Er Positive ◽

In Vivo Effects ◽

Mcf 7

Apigenin, a flavonoid, is reported to act as an estrogen receptor (ER) agonist and inhibit aromatase enzyme. However, amentoflavone, a biflavonoid bearing two apigenin molecules, has not been evaluated for its endocrine modulatory effects. Besides, it is highly consumed by young people to build muscles, enhance mood and lose weight. In the present study, apigenin was used as a reference molecule and ER mediated as well as ER-independent estrogenic/antiestrogenic activity of amentoflavone was investigated. Antitumor activity of amentoflavone was also investigated in both ER positive (MCF-7 BUS) and triple-negative (MDA-MB-231) breast cancer cells and its cytotoxicity was evaluated in human breast epithelial cells (MCF-10A). Our data confirmed ER agonist, aromatase inhibitory and cytotoxic effects of apigenin in breast cancer cells, where no ER mediated estrogenic effect and physiologically irrelevant, slight, aromatase inhibition was found for amentoflavone. Although selective cytotoxicity of amentoflavone was found in MCF-7 BUS cells, it does not seem to be an alternative to the present cytotoxic drugs. Therefore, neither an adverse effect, mediated by an estrogenic/antiestrogenic effect of amentoflavone nor a therapeutical benefit would be expected from amentoflavone. Further studies could be performed to investigate its in vivo effects.

Download Full-text

Synthesis and Biological Evaluation of 1-(Diarylmethyl)-1H-1,2,4-triazoles and 1-(Diarylmethyl)-1H-imidazoles as a Novel Class of Anti-Mitotic Agent for Activity in Breast Cancer

Pharmaceuticals ◽

10.3390/ph14020169 ◽

2021 ◽

Vol 14 (2) ◽

pp. 169

Author(s):

Gloria Ana ◽

Patrick M. Kelly ◽

Azizah M. Malebari ◽

Sara Noorani ◽

Seema M. Nathwani ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Docking Studies ◽

Biological Evaluation ◽

Mitotic Catastrophe ◽

Phase Cell ◽

Computational Docking ◽

Er Positive ◽

Mcf 7

We report the synthesis and biochemical evaluation of compounds that are designed as hybrids of the microtubule targeting benzophenone phenstatin and the aromatase inhibitor letrozole. A preliminary screening in estrogen receptor (ER)-positive MCF-7 breast cancer cells identified 5-((2H-1,2,3-triazol-1-yl)(3,4,5-trimethoxyphenyl)methyl)-2-methoxyphenol 24 as a potent antiproliferative compound with an IC50 value of 52 nM in MCF-7 breast cancer cells (ER+/PR+) and 74 nM in triple-negative MDA-MB-231 breast cancer cells. The compounds demonstrated significant G2/M phase cell cycle arrest and induction of apoptosis in the MCF-7 cell line, inhibited tubulin polymerisation, and were selective for cancer cells when evaluated in non-tumorigenic MCF-10A breast cells. The immunofluorescence staining of MCF-7 cells confirmed that the compounds targeted tubulin and induced multinucleation, which is a recognised sign of mitotic catastrophe. Computational docking studies of compounds 19e, 21l, and 24 in the colchicine binding site of tubulin indicated potential binding conformations for the compounds. Compounds 19e and 21l were also shown to selectively inhibit aromatase. These compounds are promising candidates for development as antiproliferative, aromatase inhibitory, and microtubule-disrupting agents for breast cancer.

Download Full-text

Micronutrients Selenomethionine and Selenocysteine Modulate the Redox Status of MCF-7 Breast Cancer Cells

Nutrients ◽

10.3390/nu12030865 ◽

2020 ◽

Vol 12 (3) ◽

pp. 865 ◽

Cited By ~ 1

Author(s):

Daniel Gabriel Pons ◽

Carmen Moran ◽

Marina Alorda-Clara ◽

Jordi Oliver ◽

Pilar Roca ◽

...

Keyword(s):

Breast Cancer ◽

Hydrogen Peroxide ◽

Antioxidant Enzymes ◽

Protein Expression ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Redox Status ◽

Hydrogen Peroxide Production ◽

Low Concentrations ◽

Mcf 7

Selenium is a micronutrient which is found in many foods, with redox status modulation activity. Our aim was to evaluate the effects of two chemical forms of selenoamino acids, Seleno-L-methionine and Seleno-L-cystine (a diselenide derived from selenocysteine), at different concentrations on cell viability, hydrogen peroxide production, antioxidant enzymes, UCP2 protein expression, as well as lipid and protein oxidative damage in MCF-7 breast cancer cells. Results showed that Seleno-L-methionine did not cause an increase in hydrogen peroxide production at relatively low concentrations, accompanied by a rise in the antioxidant enzymes catalase and MnSOD, and UCP2 protein expression levels. Furthermore, a decrease in protein and lipid oxidative damage was observed at 10 µM concentration. Otherwise, Seleno-L-cystine increased hydrogen peroxide production from relatively low concentrations (100 nM) to a large increase at high concentrations. Moreover, at 10 µM, Seleno-L-cystine decreased UCP2 and MnSOD protein expression. In conclusion, the chemical form of selenoamino acid and their incorporation to selenoproteins could affect the regulation of the breast cancer cell redox status. Taken together, the results obtained in this study imply that it is important to control the type of selenium-enriched nutrient consumption, taking into consideration their composition and concentration.

Download Full-text

Dynamics of Protein Expression Reveals Primary Targets and Secondary Messengers of Estrogen Receptor Alpha Signaling in MCF-7 Breast Cancer Cells

Molecular & Cellular Proteomics ◽

10.1074/mcp.m115.057257 ◽

2016 ◽

Vol 15 (6) ◽

pp. 2093-2107 ◽

Cited By ~ 17

Author(s):

Andrei P. Drabovich ◽

Maria P. Pavlou ◽

Christina Schiza ◽

Eleftherios P. Diamandis

Keyword(s):

Breast Cancer ◽

Estrogen Receptor ◽

Protein Expression ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Estrogen Receptor Alpha ◽

Receptor Alpha ◽

Secondary Messengers ◽

Mcf 7

Download Full-text

SGK3 Is an Estrogen-Inducible Kinase Promoting Estrogen-Mediated Survival of Breast Cancer Cells

Molecular Endocrinology ◽

10.1210/me.2010-0294 ◽

2011 ◽

Vol 25 (1) ◽

pp. 72-82 ◽

Cited By ~ 35

Author(s):

Yuanzhong Wang ◽

Dujin Zhou ◽

Sheryl Phung ◽

Selma Masri ◽

David Smith ◽

...

Keyword(s):

Breast Cancer ◽

Protein Kinase ◽

Cell Survival ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Dependent Manner ◽

Binding Regions ◽

Er Positive ◽

Mcf 7 ◽

Positive Breast Cancer

Serum- and glucocorticoid-inducible kinase 3 (SGK3) is a protein kinase of the AGC family of protein kinase A, protein kinase G, and protein kinase C and functions downstream of phosphatidylinositol 3-kinase (PI3K). Recent study revealed that SGK3 plays a pivotal role in Akt/protein kinase B independent signaling downstream of oncogenic PI3KCA mutations in breast cancer. Here we report that SGK3 is an estrogen receptor (ER) transcriptional target and promotes estrogen-mediated cell survival of ER-positive breast cancer cells. Through a meta-analysis on 22 microarray studies of breast cancer in the Oncomine database, we found that the expression of SGK3 is significantly higher (5.7-fold, P < 0.001) in ER-positive tumors than in ER-negative tumors. In ER-positive breast cancer cells, SGK3 expression was found to be induced by 17β-estradiol (E2) in a dose- and time-dependent manner, and the induction of SGK3 mRNA by E2 is independent of newly synthesized proteins. We identified two ERα-binding regions at the sgk3 locus through chromatin immunoprecipitation with massively parallel DNA sequencing. Promoter analysis revealed that ERα stimulates the activity of sgk3 promoters by interaction with these two ERα-binding regions on E2 treatment. Loss-of-function analysis indicated that SGK3 is required for E2-mediated cell survival of MCF-7 breast carcinoma cells. Moreover, overexpression of SGK3 could partially protect MCF-7 cells against apoptosis caused by antiestrogen ICI 182,780. Together, our study defines the molecular mechanism of regulation of SGK3 by estrogen/ER and provides a new link between the PI3K pathway and ER signaling as well as a new estrogen-mediated cell survival mechanism mediated by SGK3 in breast cancer cells.

Download Full-text

Structural and In Vitro Biological Studies of Organotin(IV) Precursors; Selective Inhibitory Activity Against Human Breast Cancer Cells, Positive to Estrogen Receptors

Australian Journal of Chemistry ◽

10.1071/ch12448 ◽

2012 ◽

Vol 65 (12) ◽

pp. 1625 ◽

Cited By ~ 25

Author(s):

Vasilis I. Balas ◽

Christina N. Banti ◽

Nikolaos Kourkoumelis ◽

Sotiris K. Hadjikakou ◽

George D. Geromichalos ◽

...

Keyword(s):

Breast Cancer ◽

Cytotoxic Activity ◽

Cancer Cells ◽

Cell Line ◽

Breast Cancer Cells ◽

X Ray ◽

Er Positive ◽

Normal Human ◽

Mcf 7

Crystals of Ph3SnCl (1) were grown from a methanol/acetonitrile solution. Compounds [Ph3SnOH]n (2) and [(Ph2Sn)4Cl2O2(OH)2] (3) were crystallized from diethyl ether/methanol/acetonitrile and hot acetone/water solutions respectively, of the white precipitation, formed by adding KOH to solutions of 1 and [Ph2SnCl2] in 1 : 1 and 1 : 2 molar ratios respectively. Complex 1 was characterized by X-ray crystallography. X-ray structure determination of compounds 2 and 3 confirmed the previously reported identities. The molecular structure of 1, reported here, is a new polymorphic form of the known one for Ph3SnCl. Four independent [Ph3SnCl] molecules constitute the crystal structure of 1. The moieties are packed in two pairs in a tail-to-tail arrangement. Complexes 1–3 were evaluated for their in vitro cytotoxic activity (cell viability) against human cancer cell lines: HeLa (human cervical), MCF-7 (breast, estrogen receptor (ER) positive), MDA-MB-231 (breast, ER negative), A549 (lung), Caki-1 (kidney carcinoma), 786-O (renal adenocarcinoma), K1 (thyroid carcinoma), and the normal human lung cell line MRC-5 (normal human fetal lung fibroblast cells) versus, the normal immortalized human mammary gland epithelial cell line MTSV17 with a sulforhodamine B (SRB) assay. The results show potent cytotoxic activity of the complexes against all cell lines used, which was superior to that of cisplatin (CDDP). Compounds 1–3 showed higher activity against breast cancer cells MCF-7 (ER positive) than against of MDA-MB-231 (ER negative). These findings prompted us to search for possible interaction of these complexes with other cellular elements of fundamental importance in cell proliferation. The influence of these complexes 1–3 upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX), as well as their binding affinity towards calf thymus-DNA, were kinetically and theoretically studied.

Download Full-text

Identification of estrogenically synthesized LRP16 as an ERα coactivator and its role in ERα-positive breast cancer

Journal of Clinical Oncology ◽

10.1200/jco.2006.24.18_suppl.10676 ◽

2006 ◽

Vol 24 (18_suppl) ◽

pp. 10676-10676

Author(s):

W. Han ◽

Y. Zhao ◽

Z. Wu ◽

Y. Mu ◽

L. Yu ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Northern Blot ◽

Breast Cancer Cells ◽

Tumor Diameter ◽

Er Positive ◽

Mcf 7 ◽

Positive Breast Cancer

10676 Background: Aberrant ERα activity is linked to genesis and malignant progression of breast cancer through direct target gene activation or repression. A complex network of coregulatory proteins is largely believed to determine the transcriptional activity of ERα. LRP16 was identified previously to be an estrogen (E2) responsive gene, but its function involving in conferring estrogen signalling pathway is not clear. Methods: Endogenous LRP16 expression in MCF-7 cells was stably suppressed by retrovirus-mediated small interference RNA (siRNA). The effects of LRP16 expression on E2-stimulated growth and invasive ability of MCF-7 cells were determined in vitro and in vivo assays. The effects of LRP16 expression on ERα transactivation were determined by luciferase assays. The interaction of LRP16 and ERα was examined by GST pull-down and coimmunopricipitation (CoIP) assays. Northern blot and Western blot were used to detect the mRNA and protein levels of ER target genes in LRP16-inhibited MCF-7 cells. The LRP16 expression levels in primary breast cancer were detected by Northern blot. Results: Fristly, LRP16 expression was characterized to be dependent on estrogen activities. Then, LRP16 was identified to be an estrogen-independent ERα cofactor in ER-positive breast cancer cells and demonstrate that LRP16 is an essential coactivator to ERα-mediated transactivation in an estrogen-dependent manner. Suppression of LRP16 expression in ER-positive breast cancer cells specifically inhibits the transcription of ER upregulated genes, results in the increase of E-cadherin expression through ER mediation. In vitro and in vivo data demonstrate that suppression of LRP16 inhibits the ability of estrogen-stimulated proliferation and invasiveness of ER-positive breast cancer cells. The pathological and clinical characteristics of human breast cancer includining ER/PR-positiveness, tumor diameter and the involvement of axillary lymphoid nodes were tightly linked with the LRP16 gene expression level. Conclusions: These results establish a mechanistic link between estrogen receptor status, its coactivator LRP16, and progression of ER-positive breast cancers, and may provide a novel antiestrogenic target for the therapy of ER positive breast cancer. No significant financial relationships to disclose.

Download Full-text