scholarly journals Activating transcription factor-2 (ATF2) is a key determinant of resistance to endocrine treatment in an in vitro model of breast cancer

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Athina Giannoudis ◽  
Mohammed Imad Malki ◽  
Bharath Rudraraju ◽  
Hisham Mohhamed ◽  
Suraj Menon ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Transcription Factor ◽  
Endocrine Resistance ◽  
Endocrine Treatment ◽  
Mcf7 Cells ◽  
Microarray Gene Expression ◽  
Mcf7 Cell Line ◽  
Activating Transcription Factor

Abstract Background Activating transcription factor-2 (ATF2), a member of the leucine zipper family of DNA binding proteins, has been implicated as a tumour suppressor in breast cancer. However, its exact role in breast cancer endocrine resistance is still unclear. We have previously shown that silencing of ATF2 leads to a loss in the growth-inhibitory effects of tamoxifen in the oestrogen receptor (ER)-positive, tamoxifen-sensitive MCF7 cell line and highlighted that this multi-faceted transcription factor is key to the effects of tamoxifen in an endocrine sensitive model. In this work, we explored further the in vitro role of ATF2 in defining the resistance to endocrine treatment. Materials and methods We knocked down ATF2 in TAMR, LCC2 and LCC9 tamoxifen-resistant breast cancer cell lines as well as the parental tamoxifen sensitive MCF7 cell line and investigated the effects on growth, colony formation and cell migration. We also performed a microarray gene expression profiling (Illumina Human HT12_v4) to explore alterations in gene expression between MCF7 and TAMRs after ATF2 silencing and confirmed gene expression changes by quantitative RT-PCR. Results By silencing ATF2, we observed a significant growth reduction of TAMR, LCC2 and LCC9 with no such effect observed with the parental MCF7 cells. ATF2 silencing was also associated with a significant inhibition of TAMR, LCC2 and LCC9 cell migration and colony formation. Interestingly, knockdown of ATF2 enhanced the levels of ER and ER-regulated genes, TFF1, GREB1, NCOA3 and PGR, in TAMR cells both at RNA and protein levels. Microarray gene expression identified a number of genes known to mediate tamoxifen resistance, to be differentially regulated by ATF2 in TAMR in relation to the parental MCF7 cells. Moreover, differential pathway analysis confirmed enhanced ER activity after ATF2 knockdown in TAMR cells. Conclusion These data demonstrate that ATF2 silencing may overcome endocrine resistance and highlights further the dual role of this transcription factor that can mediate endocrine sensitivity and resistance by modulating ER expression and activity.

scholarly journals Non-canonical AR activity facilitates endocrine resistance in breast cancer

2019 ◽  
Vol 26 (2) ◽  
pp. 251-264 ◽  
Author(s):  
KeeMing Chia ◽  
Heloisa Milioli ◽  
Neil Portman ◽  
Geraldine Laven-Law ◽  
Rhiannon Coulson ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Clinical Trials ◽  
Endocrine Resistance ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Breast Cancer Cell Lines ◽  
Microarray Gene Expression ◽  
Pdx Model

The role of androgen receptor (AR) in endocrine-resistant breast cancer is controversial and clinical trials targeting AR with an AR antagonist (e.g., enzalutamide) have been initiated. Here, we investigated the consequence of AR antagonism using in vitro and in vivo models of endocrine resistance. AR antagonism in MCF7-derived tamoxifen-resistant (TamR) and long-term estrogen-deprived breast cancer cell lines were achieved using siRNA-mediated knockdown or pharmacological inhibition with enzalutamide. The efficacy of enzalutamide was further assessed in vivo in an estrogen-independent endocrine-resistant patient-derived xenograft (PDX) model. Knockdown of AR inhibited the growth of the endocrine-resistant cell line models. Microarray gene expression profiling of the TamR cells following AR knockdown revealed perturbations in proliferative signaling pathways upregulated in endocrine resistance. AR loss also increased some canonical ER signaling events and restored sensitivity of TamR cells to tamoxifen. In contrast, enzalutamide did not recapitulate the effect of AR knockdown in vitro, even though it inhibited canonical AR signaling, which suggests that it is the non-canonical AR activity that facilitated endocrine resistance. Enzalutamide had demonstrable efficacy in inhibiting AR activity in vivo but did not affect the growth of the endocrine-resistant PDX model. Our findings implicate non-canonical AR activity in facilitating an endocrine-resistant phenotype in breast cancer. Unlike canonical AR signaling which is inhibited by enzalutamide, non-canonical AR activity is not effectively antagonized by enzalutamide, and this has important implications in the design of future AR-targeted clinical trials in endocrine-resistant breast cancer.

scholarly journals Viability of MCF7 Cells Exposed to Basolateral Secretion from CaCo2 Cells Pretreated with Fecal Waters from Breast Cancer Patients and Controls

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 308-308
Author(s):  
Jean-Marie Bard ◽  
Christine Bobin-Dubigeon ◽  
Huyen-Trang Luu ◽  
Françoise Le Vacon ◽  
Thomas Carton ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Regression Model ◽  
Breast Cancer Patients ◽  
Cell Secretion ◽  
Mcf7 Cells ◽  
Cancer Disease ◽  
Caco2 Cells ◽  
Bacterial Groups

Abstract Objectives There is increasing evidence suggesting that microbiota may play a role in breast cancer disease and influence the disease severity. Several mechanisms may be involved in this relationship. Our hypothesis is that the role of microbiota in the disease may be at least partly related to its influence in gut lipid and lipoprotein metabolisms. This hypothesis was tested in an in vitro model combining MCF7 and Caco2 cells. Methods 32 women newly diagnosed for breast cancer, before any treatment and 28 apparently healthy women provided their stools from which bacterial DNA was extracted and amplified by qPCR, targeting 16S rRNA sequences specific to bacterial groups. Fecal waters (FW) were also obtained from these stools. Intestinal Caco-2 cells grown on filter inserts were incubated apically with 10% FW for 24 h. Then, MCF-7 cells were incubated with the whole basolateral medium for 24 h. The viability of these cells was estimated by MTT test. In parallel, LXR, apolipoproteins AIV and E gene expression was estimated by RT QPCR in CaCo2 cells and short chain fatty acids (SCFA) were quantified in FW. A logistic regression model was used to establish the Odds ratios (OR) for the disease of MCF7 viability and CaCo2 gene expression. The relationship between % bacterial groups, CaCo2 gene expression, SCFA and viability was established by regression models. Results Patients and controls differed by the MCF7 viability (1.05 [1.01–1.10], p = 0.04) and a tendency towards a difference was observed for apo AIV gene expression (0.63 [0.39–1.01], p = 0.055), (OR [5th-95th]). Viability was positively correlated with % Bifidobacterium sp.  (21.18 ± 7.66, p = 0.008) and negatively correlated with valerate (−2.849 ± 1.048, p = 0.009), (ß±s.d.). These correlations were maintained in a multiple regression model. Conclusions Microbiota may interact with intestine cell lipid metabolism and therefore influence cancer disease through gut cell secretion or permeability. Funding Sources Ligue Contre le cancer and private funds from Integrated Center for Oncology.

scholarly journals Hypoxia-induced switch in SNAT2/SLC38A2 regulation generates endocrine resistance in breast cancer

2019 ◽  
Vol 116 (25) ◽  
pp. 12452-12461 ◽  
Author(s):  
Matteo Morotti ◽  
Esther Bridges ◽  
Alessandro Valli ◽  
Hani Choudhry ◽  
Helen Sheldon ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Hypoxia Inducible Factor ◽  
Tumor Hypoxia ◽  
Endocrine Resistance ◽  
Regulatory Elements ◽  
Estrogen Receptor Α ◽  
Mcf7 Cells ◽  
Glutamine Transporter

Tumor hypoxia is associated with poor patient outcomes in estrogen receptor-α–positive (ERα+) breast cancer. Hypoxia is known to affect tumor growth by reprogramming metabolism and regulating amino acid (AA) uptake. Here, we show that the glutamine transporter, SNAT2, is the AA transporter most frequently induced by hypoxia in breast cancer, and is regulated by hypoxia both in vitro and in vivo in xenografts. SNAT2 induction in MCF7 cells was also regulated by ERα, but it became predominantly a hypoxia-inducible factor 1α (HIF-1α)–dependent gene under hypoxia. Relevant to this, binding sites for both HIF-1α and ERα overlap in SNAT2’s cis-regulatory elements. In addition, the down-regulation of SNAT2 by the ER antagonist fulvestrant was reverted in hypoxia. Overexpression of SNAT2 in vitro to recapitulate the levels induced by hypoxia caused enhanced growth, particularly after ERα inhibition, in hypoxia, or when glutamine levels were low. SNAT2 up-regulation in vivo caused complete resistance to antiestrogen and, partially, anti-VEGF therapies. Finally, high SNAT2 expression levels correlated with hypoxia profiles and worse outcome in patients given antiestrogen therapies. Our findings show a switch in the regulation of SNAT2 between ERα and HIF-1α, leading to endocrine resistance in hypoxia. Development of drugs targeting SNAT2 may be of value for a subset of hormone-resistant breast cancer.

Investigating tamoxifen resistance in the luminal B estrogen receptor positive breast cancer subtype: Tailoring treatment in hormone responsive breast cancer

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 10603-10603 ◽  
Author(s):  
S. Loi ◽  
C. Sotiriou ◽  
B. Haibe-Kains ◽  
F. Lallemand ◽  
N. Conus ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Her2 Overexpression ◽  
Mcf7 Cells ◽  
Luminal A ◽  
Gene Set ◽  
Luminal B ◽  
Vitro Model ◽  
Her2 Signaling

10603 Background: We recently reported that the two estrogen receptor (ER) positive breast cancer (BC) molecular subtypes can be defined by their expression of proliferation genes using a gene expression index (GGI): the luminal A and B subtypes have low and high levels respectively (J Clin Onc, in press). When treated with adjuvant tamoxifen, luminal A tumors have a good prognosis, however the clinical outcome of the luminal B subtype was poor. This study aimed to explain the biological basis for these observations using global gene expression profiling and an in vitro model of ER+ BC. Methods: 246 ER+ BC samples from women treated with adjuvant tamoxifen monotherapy were analyzed with affymetrix gene expression arrays and evaluated using gene set enrichment analysis (GSEA). ER+ MCF-7 BC cells (control) treated with tamoxifen (TAM) and heregulin (HRG) were used to investigate molecular pathways identified using GSEA. Results: We found that a gene set suggesting ERBB2 pathway activation was significantly enriched in the luminal B subtype (p=0.02). Only 10% of samples overexpressed HER2 by immunohistochemistry, suggesting that activation of HER2 signaling pathways is independent of HER2 overexpression and may contribute to TAM resistance in this subtype. To validate this hypothesis, MCF-7 cell-lines were treated with HRG (HRG-MCF7) to create a model of ERBB2 pathway activation. HRG-MCF7 cells displayed phosphorylation of HER2/3 without HER2 overexpression. Treatment with HRG overcame TAM induced cell cycle arrest with higher S-phase fraction (p<0.01) and increased anchorage- independent colony formation (p<0.01). Gene expression profiling confirmed significant enrichment of the ERBB2 gene set (p<0.01) and higher GGI levels (p=0.02) in HRG-MCF7 cells compared with control. Conclusions: HRG-MCF7 cells may be useful as an in vitro model of the TAM resistant luminal B subtype. In this group, targeting activated HER2 signaling may be a helpful treatment strategy despite the lack of HER2 overexpression. Our data suggests that agents like lapatinib may be effective only in the luminal B and not the luminal A tumors, demonstrating the importance of stratifying by subtype in future clinical trials of ER+ disease. No significant financial relationships to disclose.

Melatonin Differentially Modulates NF-кB Expression in Breast and Liver Cancer Cells

2019 ◽  
Vol 18 (12) ◽  
pp. 1688-1694 ◽  
Author(s):  
Jucimara Colombo ◽  
Bruna V. Jardim-Perassi ◽  
João P.S. Ferreira ◽  
Cristine Z. Braga ◽  
Nathália M. Sonehara ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Transcription Factor ◽  
Liver Cancer ◽  
Cancer Cells ◽  
Hepg2 Cells ◽  
In Vitro Study ◽  
Inhibitory Effect

Background: NF-kB (nuclear factor kappa B) is a transcription factor composed of two subunits, p50 and p65, which plays a key role in the inflammatory process. Melatonin has oncostatic, antiangiogenic and antimetastatic properties, and some recent studies have indicated an inhibitory effect of melatonin on NF-kB in some types of cancer. This work aims to investigate the effects of melatonin treatment on the expression of NFkB in breast and liver cancer models. Method: The breast cancer xenographic model was performed using female Balb/c nude athymic mice injected with MDA-MB-231 cells. The animals were treated with 40 mg/Kg of melatonin for 21 days. Volume of the tumors was measured with a digital caliper. Hepatocarcinoma model was developed by using the HepG2 cells in vitro, treated with 1 mM melatonin for 24 h. The expression of NF-kB protein was verified by immunohistochemistry and immunocytochemistry and quantified by optical densitometry, in vivo study and in vitro study, respectively. NF-kB gene expression was performed by quantitative RT-PCR. Results: The breast cancer xenografts nude mice treated with melatonin showed reduced tumor size (P=0.0022). There was a decrease in NF-kB protein staining (P=0.0027) and gene expression (P=0.0185) in mice treated with melatonin. The opposite results were observed for the hepatocarcinoma model. HepG2 cells treated with melatonin showed an increase in the NF-kB immunostaining when compared to control cells (P=0.0042). Conclusion: Our results indicated that the treatment with melatonin was able to decrease both gene and protein expressions of NF-kB in breast cancer cells and, conversely, increase the transcription factor protein expression in hepatocarcinoma cells. These data highlighted a double role in the expression of NF-kB, depending on the cell type. Further studies are needed to better elucidate the action of melatonin in NF-kB, since this transcription factor acts on different signaling pathways that are fundamental for carcinogenesis.

scholarly journals Hypoxia-induced switch in SNAT2/SLC38A2 regulation generates endocrine-resistance in breast cancer

2018 ◽  
Author(s):  
Matteo Morotti ◽  
Esther Bridges ◽  
Alessandro Valli ◽  
Hani Choudhry ◽  
Helen Sheldon ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Hypoxia ◽  
Endocrine Resistance ◽  
Estrogen Therapy ◽  
Regulatory Elements ◽  
Estrogen Receptor Α ◽  
Mcf7 Cells ◽  
Glutamine Transporter

AbstractTumor hypoxia is associated with poor patient outcomes in estrogen receptor-α (ERα) positive breast cancer. Hypoxia is known to affect tumor growth by reprogramming metabolism and regulating amino acid (AA) uptake. Here we show that the glutamine transporter, SNAT2, is the AA transporter most frequently induced by hypoxia in breast cancer and it is regulated by HIF1α bothin-vitroandin-vivoin xenografts. SNAT2 induction in MCF7 cells was also regulated by ERα but it became predominantly a HIF-1α-dependent gene under hypoxia. Relevant to this, binding sites for both HIF-1α and ERα overlap in SNAT2’s cis-regulatory elements. In addition, the downregulation of SNAT2 by the ER antagonist fulvestrant was reverted in hypoxia.Overexpression of SNAT2in-vitroto recapitulate the levels induced by hypoxia caused enhanced growth, particularly after ERα inhibition, in hypoxia, or when glutamine levels were low. SNAT2 upregulationin-vivocaused complete resistance to anti-estrogen and, partially, anti-VEGF therapies. Finally, high SNAT2 expression levels correlate with HIF-1α and worse outcome in patients given anti-estrogen therapy. Our findings show a switch in regulation of SNAT2 between ERα and HIF-1α, leading to endocrine resistance in hypoxia. Development of drugs targeting SNAT2 may be of value for a subset of hormone-resistant breast cancer.

Gene Expression Assay in the Management of Early Breast Cancer

2020 ◽  
Vol 27 (17) ◽  
pp. 2826-2839 ◽  
Author(s):  
Roberta Caputo ◽  
Daniela Cianniello ◽  
Antonio Giordano ◽  
Michela Piezzo ◽  
Maria Riemma ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Decision Making ◽  
Adjuvant Chemotherapy ◽  
Early Breast Cancer ◽  
Treatment Decision ◽  
Endocrine Treatment ◽  
Expression Ratio ◽  
Treatment Decision Making ◽  
Low Sensitivity

The addition of adjuvant chemotherapy to hormonal therapy is often considered questionable in patients with estrogen receptor-positive early breast cancer. Low risk of disease relapse after endocrine treatment alone and/or a low sensitivity to chemotherapy are reasons behind not all patients benefit from chemotherapy. Most of the patients could be exposed to unnecessary treatment- related adverse events and health care costs when treatment decision-making is based only on classical clinical histological features. Gene expression profile has been developed to refine physician’s decision-making process and to tailor personalized treatment to patients. In particular, these tests are designed to spare patients the side effects of unnecessary treatment, and ensure that adjuvant chemotherapy is correctly recommended to patients with early breast cancer. In this review, we will discuss the main diagnostic tests and their potential clinical applications (Oncotype DX, MammaPrint, PAM50/Prosigna, EndoPredict, MapQuant Dx, IHC4, and Theros-Breast Cancer Gene Expression Ratio Assay).

Coumarin-Fatty Acid Conjugates as Potential ERα/AKT-1 Antagonists for ER Positive Breast Cancer

2020 ◽  
Vol 20 (4) ◽  
pp. 437-449
Author(s):  
Jubie Selvaraj ◽  
Jameera B.A. John ◽  
Nanjan M. Joghee ◽  
Justin Antony ◽  
Ashish Wadhwani ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Fatty Acid ◽  
Binding Assay ◽  
Uterine Cancer ◽  
Design Development ◽  
Structure Based Drug Design ◽  
Ic50 Values ◽  
Cancer Activity

Background: : Current drugs used for the treatment of hormone-dependent breast cancer function as anti-estrogens in the breast, in addition to Estrogen Receptor (ER) agonists in the uterus, thus elevate a woman’s risk of developing uterine cancer. This is due to the lack of selective binding and partial agonistic effect of these drugs towards estrogen receptors. In recent years, therefore, researchers have turned their attention towards antiestrogens devoid of these agonist properties and thus have a mechanism of action different from the existing drugs. Objective:: In this context, we report here the design, development and in vitro evaluation of some novel pharmacophores containing coumarin and fatty acid scaffolds for their anti-breast cancer activity. Methods: : A library of coumarin-fatty acid conjugates was designed using structure-based drug design approach. The conjugates which have shown good in silico results were then synthesized, characterized and evaluated for their anti-breast cancer activity by MTT assay, Apoptotic assay, Cell proliferation assay, Estrogen binding assay and Gene expression study. Results: Out of the fifteen compounds screened, two compounds, SAC-2 and LNAC-2, showed good activity with IC50 values 22µg/ml, 25μg/ml, respectively. These compounds suppressed the proliferation of ER overexpressed MCF-7 cells, increased ERα degradation and hence inactivate the ERα pathway. ER binding assay and gene expression RT-PCR study reveal that SAC-2 downregulated the expression of ERα receptor and AKT-1 gene. Conclusion:: Compound SAC-2 is a good antagonist to ER and hence has a potential for treating breast cancer and other cancers where AKT plays an important role.

Subnuclear compartmentalization of sequence-specific transcription factors and regulation of eukaryotic gene expression

2005 ◽  
Vol 83 (4) ◽  
pp. 535-547 ◽  
Author(s):  
Gareth N Corry ◽  
D Alan Underhill
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Current Knowledge ◽  
Nuclear Architecture ◽  
Subnuclear Localization ◽  
Modular Structures

To date, the majority of the research regarding eukaryotic transcription factors has focused on characterizing their function primarily through in vitro methods. These studies have revealed that transcription factors are essentially modular structures, containing separate regions that participate in such activities as DNA binding, protein–protein interaction, and transcriptional activation or repression. To fully comprehend the behavior of a given transcription factor, however, these domains must be analyzed in the context of the entire protein, and in certain cases the context of a multiprotein complex. Furthermore, it must be appreciated that transcription factors function in the nucleus, where they must contend with a variety of factors, including the nuclear architecture, chromatin domains, chromosome territories, and cell-cycle-associated processes. Recent examinations of transcription factors in the nucleus have clarified the behavior of these proteins in vivo and have increased our understanding of how gene expression is regulated in eukaryotes. Here, we review the current knowledge regarding sequence-specific transcription factor compartmentalization within the nucleus and discuss its impact on the regulation of such processes as activation or repression of gene expression and interaction with coregulatory factors.Key words: transcription, subnuclear localization, chromatin, gene expression, nuclear architecture.

scholarly journals MCM3 upregulation confers endocrine resistance in breast cancer and is a predictive marker of diminished tamoxifen benefit

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Sanne Løkkegaard ◽  
Daniel Elias ◽  
Carla L. Alves ◽  
Martin V. Bennetzen ◽  
Anne-Vibeke Lænkholm ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cancer Patients ◽  
Endocrine Therapy ◽  
Endocrine Resistance ◽  
Predictive Marker ◽  
Endocrine Treatment ◽  
Breast Cancer Patients ◽  
Minichromosome Maintenance ◽  
Primary Tumors

AbstractResistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancer is a major clinical problem with poorly understood mechanisms. There is an unmet need for prognostic and predictive biomarkers to allow appropriate therapeutic targeting. We evaluated the mechanism by which minichromosome maintenance protein 3 (MCM3) influences endocrine resistance and its predictive/prognostic potential in ER+ breast cancer. We discovered that ER+ breast cancer cells survive tamoxifen and letrozole treatments through upregulation of minichromosome maintenance proteins (MCMs), including MCM3, which are key molecules in the cell cycle and DNA replication. Lowering MCM3 expression in endocrine-resistant cells restored drug sensitivity and altered phosphorylation of cell cycle regulators, including p53(Ser315,33), CHK1(Ser317), and cdc25b(Ser323), suggesting that the interaction of MCM3 with cell cycle proteins is an important mechanism of overcoming replicative stress and anti-proliferative effects of endocrine treatments. Interestingly, the MCM3 levels did not affect the efficacy of growth inhibitory by CDK4/6 inhibitors. Evaluation of MCM3 levels in primary tumors from four independent cohorts of breast cancer patients receiving adjuvant tamoxifen mono-therapy or no adjuvant treatment, including the Stockholm tamoxifen (STO-3) trial, showed MCM3 to be an independent prognostic marker adding information beyond Ki67. In addition, MCM3 was shown to be a predictive marker of response to endocrine treatment. Our study reveals a coordinated signaling network centered around MCM3 that limits response to endocrine therapy in ER+ breast cancer and identifies MCM3 as a clinically useful prognostic and predictive biomarker that allows personalized treatment of ER+ breast cancer patients.

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