scholarly journals ELOVL2: a novel tumor suppressor attenuating tamoxifen resistance in breast cancer

2020 ◽  
Author(s):  
Dawoon Jeong ◽  
Juyeon Ham ◽  
Hyeon Woo Kim ◽  
Heejoo Kim ◽  
Hwee Won Ji ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Drug Resistance ◽  
Cancer Patients ◽  
Tumor Tissue ◽  
Tamoxifen Resistance ◽  
Colony Formation Assay ◽  
Breast Cancer Patients ◽  
Methylation Analysis ◽  
Genome Wide ◽  
Mcf 7

Abstract Background To comprehensively understand the molecular mechanism of tamoxifen resistance (TamR) acquisition by epigenetically regulated genes, it is essential to identify pivotal genes by genome-wide methylation analysis and verify their function in xenograft animal model and cancer patients. Methods The MCF-7/TamR breast cancer cell line was developed and a genome-wide methylation array was performed. The methylation and expression of ELOVL2 was validated in cultured cells, xenografted tumor tissue, and breast cancer patients by methylation-specific PCR, qRT-PCR, Western blot analysis, and immunohistochemistry. Deregulation of ELOVL2 and THEM4 was achieved using siRNA or generating stable transfectants. Tam sensitivity, cell growth, and apoptosis were monitored by colorimetric and colony formation assay and flow cytometric analysis. Pathway analysis was performed to generate networks for the differentially methylated genes in the MCF-7/TamR cells and for the differentially expressed genes in the ELOVL2-overexpressing cells. Results Genome-wide methylation analysis in the MCF-7/TamR cells identified elongation of very-long chain fatty acid protein 2 (ELOVL2) to be significantly hypermethylated and downregulated, which was further verified in the tumor tissues from TamR breast cancer patients (n = 28) compared with those from Tam-sensitive (TamS) patients (n = 33) (P < 0.001). Immunohistochemical analysis of tissues from cancer patients showed lower expression of ELOVL2 in the TamR than TamS tissues. Growth of the MCF-7/TamR cells overexpressing ELOVL2 was retarded in cell culture and also in xenograft tumor tissue. Strikingly, ELOVL2 attenuated resistance to Tam up to 70% judged by the colorimetric and colony formation assay and xenograft mouse model. ELOVL2 contributed to the recovery of Tam sensitivity by regulating a group of genes in the AKT and ERα signaling pathways, e.g., THEM4, which plays crucial roles in drug resistance. Conclusions ELOVL2 was hypermethylated and downregulated in TamR breast cancer patients compared with TamS patients. ELOVL2 is responsible for the recovery of Tam sensitivity. AKT- and ERα-hubbed networks are pivotal in ELOVL2 signaling, where THEM4 contributes to the relaying ELOVL2 signaling. This study implies that deregulation of a gene in fatty acid metabolism can lead to drug resistance, giving insight into the development of a new therapeutic strategy for drug-resistant breast cancer.

scholarly journals Identification and Analysis of Estrogen Receptor α Promoting Tamoxifen Resistance-Related lncRNAs

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xiulei Zhang ◽  
Shanjun Gao ◽  
Zhen Li ◽  
Wei Wang ◽  
Guangzhi Liu
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Patients ◽  
Estrogen Receptor Alpha ◽  
Acquired Resistance ◽  
Tamoxifen Resistance ◽  
Estrogen Receptor Α ◽  
Rna Seq ◽  
Breast Cancer Patients ◽  
Mcf 7

70-75% breast cancer patients are estrogen receptor alpha positive (ERα+), and the antiestrogen drug tamoxifen has been used for the past three decades. However, in 20-30% of these patients, tamoxifen therapy fails due to intrinsic or acquired resistance. A previous study has showed ERα signaling still exerts significant roles in the development of tamoxifen resistance and several lncRNAs have been demonstrated important roles in tamoxifen resistance. But ERα directly regulated and tamoxifen resistance related lncRNAs remain to be discovered. We reanalyze the published ERα chromatin immunoprecipitation-seq (ChIP-seq) and RNA-seq data of tamoxifen-sensitive (MCF-7/WT) and tamoxifen-resistant (MCF-7/TamR) breast cancer cells. We demonstrate that there are differential ERα recruitment events and the differentials may alert the expression profile in MCF-7/WT and MCF-7/TamR cells. Furthermore, we make an overlap of the ERα binding lncRNAs and differentially expressed lncRNAs and get 49 ERα positively regulated lncRNAs. Among these lncRNAs, the expression levels of AC117383.1, AC144450.1, RP11-15H20.6, and ATXN1-AS1 are negatively correlated with the survival probability of breast cancer patients and ELOVL2-AS1, PCOLCE-AS1, ITGA9-AS1, and FLNB-AS1 are positively correlated. These lncRNAs may be potential diagnosis or prognosis markers of tamoxifen resistance.

scholarly journals Antiestrogen-resistant human breast cancer cells require activated Protein Kinase B/Akt for growth

2005 ◽  
Vol 12 (3) ◽  
pp. 599-614 ◽  
Author(s):  
T Frogne ◽  
J S Jepsen ◽  
S S Larsen ◽  
C K Fog ◽  
B L Brockdorff ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Cell Lines ◽  
Human Breast Cancer ◽  
Neutralizing Antibodies ◽  
Breast Cancer Cells ◽  
Resistant Cell ◽  
Breast Cancer Patients ◽  
Human Breast ◽  
Mcf 7

Development of acquired resistance to antiestrogens is a major clinical problem in endocrine treatment of breast cancer patients. The IGF system plays a profound role in many cancer types, including breast cancer. Thus, overexpression and/or constitutive activation of the IGF-I receptor (IGF-IR) or different components of the IGF-IR signaling pathway have been reported to render breast cancer cells less estrogen dependent and capable of sustaining cell proliferation in the presence of antiestrogens. In this study, growth of the antiestrogen-sensitive human breast cancer cell line MCF-7 was inhibited by treatment with IGF-IR-neutralizing antibodies. In contrast, IGF-IR-neutralizing antibodies had no effect on growth of two different antiestrogen-resistant MCF-7 sublines. A panel of antiestrogen-resistant cell lines was investigated for expression of IGF-IR and either undetectable or severely reduced IGF-IR levels were observed. No increase in insulin receptor substrate 1 (IRS-1) or total PKB/Akt (Akt) was detected in the resistant cell lines. However, a significant increase in phosphorylated Akt (pAkt) was found in four of six antiestrogen-resistant cell lines. Overexpression of pAkt was associated with increased Akt kinase activity in both a tamoxifen- and an ICI 182,780-resistant cell line. Inhibition of Akt phosphorylation by the phosphatidylinositol 3-kinase (PI3-K) inhibitor wortmannin or the Akt inhibitor SH-6 (structurally modified phosphatidyl inositol ether liquid analog PIA 6) resulted in a more pronounced growth inhibitory effect on the antiestrogen-resistant cells compared with the parental cells, suggesting that signaling via Akt is required for antiestrogen-resistant cell growth in at least a subset of our antiestrogen-resistant cell lines. PTEN expression and activity was not decreased in cell lines overexpressing pAkt. Our data demonstrate that Akt is a target for treatment of antiestrogen-resistant breast cancer cell lines and we suggest that antiestrogen-resistant breast cancer patients may benefit from treatment targeted to inhibit Akt signaling.

Genome-Wide Methylation Analysis Identifies NOX4 and KDM5A as Key Regulators in Inhibiting Breast Cancer Cell Proliferation by Ginsenoside Rg3

2018 ◽  
Vol 46 (06) ◽  
pp. 1333-1355 ◽  
Author(s):  
Juyeon Ham ◽  
Seungyeon Lee ◽  
Hyunkyung Lee ◽  
Dawoon Jeong ◽  
Sungbin Park ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Proliferation ◽  
Cell Growth ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Growth Effect ◽  
Breast Cancer Patients ◽  
Ginsenoside Rg3 ◽  
Methylation Analysis ◽  
Genome Wide

Ginsenoside Rg3 is a key metabolite of ginseng and is known to inhibit cancer cell growth. However, the epigenetics of CpG methylation and its regulatory mechanism have yet to be determined. Genome-wide methylation analysis of MCF-7 breast cancer cells treated with Rg3 was performed to identify epigenetically regulated genes and pathways. The effect of Rg3 on apoptosis and cell proliferation was examined by a colony formation assay and a dye-based cell proliferation assay. The association between methylation and gene expression was monitored by RT-PCR and Western blot analysis. Genome-wide methylation analysis identified the “cell morphology”-related pathway as the top network. Rg3 induced late stage apoptosis but inhibited cell proliferation up to 60%. Hypermethylated TRMT1L, PSMC6 and NOX4 were downregulated by Rg3, while hypomethylated ST3GAL4, RNLS and KDM5A were upregulated. In accordance, downregulation of NOX4 by siRNA abrogated the cell growth effect of Rg3, while the effect was opposite for KDM5A. Notably, breast cancer patients with a higher expression of NOX4 and KDM5A showed poor and good prognosis of survival, respectively. In conclusion, Rg3 deregulated tumor-related genes through alteration of the epigenetic methylation level leading to growth inhibition of cancer cells.

scholarly journals Association Between Pak1 Expression and Subcellular Localization and Tamoxifen Resistance in Breast Cancer Patients

2006 ◽  
Vol 98 (10) ◽  
pp. 671-680 ◽  
Author(s):  
Caroline Holm ◽  
Suresh Rayala ◽  
Karin Jirström ◽  
Olle Stål ◽  
Rakesh Kumar ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Subcellular Localization ◽  
Cancer Patients ◽  
Tamoxifen Resistance ◽  
Breast Cancer Patients ◽  
Pak1 Expression

scholarly journals Prevalence of ESR1 E380Q mutation in tumor tissue and plasma from Japanese breast cancer patients

BMC Cancer ◽  
2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Takashi Takeshita ◽  
Yutaka Yamamoto ◽  
Mutsuko Yamamoto-Ibusuki ◽  
Aiko Sueta ◽  
Mai Tomiguchi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Tumor Tissue ◽  
Breast Cancer Patients

Chemokine CXCL13 is overexpressed in the tumor tissue and in the peripheral blood of breast cancer patients

2008 ◽  
Vol 26 (15_suppl) ◽  
pp. 22029-22029
Author(s):  
D. Atanackovic ◽  
Y. Hildebrandt ◽  
A. Marx ◽  
Y. Cao ◽  
C. Bokemeyer ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Peripheral Blood ◽  
Tumor Tissue ◽  
Breast Cancer Patients

Translational cell study exploring the role of estrogen receptor β expression as a predictive and/or prognostic factor in breast cancer patients

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e22185-e22185
Author(s):  
S. Saji ◽  
N. Honma ◽  
M. Hirose ◽  
S. Hayashi ◽  
K. Kuroi
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cell Line ◽  
Cancer Patients ◽  
Triple Negative ◽  
Breast Cancer Patients ◽  
Her 2 ◽  
Mcf 7 ◽  
Cell Study ◽  
Positive Breast Cancer

e22185 Background: We have reported that positive expression of Estrogen receptor β (ERβ) was associated with better prognosis in the early breast cancer patients treated with adjuvant tamoxifen monotherapy (J Clin Oncol. 2008). In addition, this was also true in the ERα-negative/PR-negative/Her-2 negative patients. We explored the biological impact of ERβ in breast cancer cell lines to determine whether these observations were due to its prognostic power or predictive power of response to the therapy. Methods: Since MCF-7 cell was ERβ-negative ERα-positive cell line, we established two stable clones of MCF-7 by introducing ERβ expression vector (β-clone 1, β-clone 2) as the model of ERβ-positive ERα-positive breast cancer. MDA-MB 231 cell was used as ERβ-positive triple-negative cell line. These cells were subjected to proliferation, expression and functional analysis. Results: In western blotting, both β-clone 1 and clone 2 showed decreased expression of PR and Her-2 than parent MCF-7, although there were no differences in ERα expression. Expression of ERβ decreased estradiol (E2) induced proliferation ability and rate of cells in S-phase cycle. PPT (ERα-specific agonist) and DPN (ERβ-specific agonist) did not show any difference in response, and IC 50 for 4 OH-tamoxifen and fulvestrant did not differ among MCF-7, β-clone 1 and clone 2 (0.05–0.1 μM). Whereas, cell death due to deprivation of E2 from 1nM to 1pM was more frequently observed in ERβ-expressing clones than in parent MCF-7 cell. These cell deaths did not involve standard apoptosis pathway with caspase-3/7 activation and PARP cleavage. E2, DPN and PPT did not affect the proliferation of ERβ-positive triple negative MDA-MB 231 cell, and IC 50 for 4-OH tamoxifen was too high (8 μM) to be achieved in clinical pharmacological dose. Conclusions: From our cell study, better prognosis of ERβ-positive breast cancer patient who treated with adjuvant tamoxifen is mainly due to its own favorable biological behavior. However, this prognostic impact may include the favorable response to the treatment, when we use estrogen-deprivation therapy such as aromatase inhibitors (AIs). Additional clinical study in AI users would be required to address this issue. No significant financial relationships to disclose.

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