Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA112729 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:One-third of all ER+ breast tumors treated with endocrine therapy fail to respond, and the remainder are likely to relapse in the future. Almost all data on endocrine resistance has been obtained in models of invasive ductal carcinoma (IDC). However, invasive lobular carcinomas (ILC) comprise up to 15% of newly diagnosed invasive breast cancers diagnosed each year and, while the incidence of IDC has remained relatively constant during the last 20 years, the prevalence of ILC continues to increase among postmenopausal women. We report a new model of Tamoxifen (TAM)-resistant invasive lobular breast carcinoma cells that provides novel insights into the molecular mechanisms of endocrine resistance. SUM44 cells express ER and are sensitive to the growth inhibitory effects of antiestrogens. Selection for resistance to 4-hydroxytamoxifen led to the development of the SUM44/LCCTam cell line, which exhibits decreased expression of estrogen receptor alpha (ERα) and increased expression of the estrogen-related receptor gamma (ERRγ). Knockdown of ERRγ in SUM44/LCCTam cells by siRNA restores TAM sensitivity, and overexpression of ERRγ blocks the growth-inhibitory effects of TAM in SUM44 and MDA-MB-134 VI lobular breast cancer cells. ERRγ-driven transcription is also increased in SUM44/LCCTam, and inhibition of activator protein 1 (AP1) can restore or enhance TAM sensitivity. These data support a role for ERRγ/AP1 signaling in the development of TAM resistance, and suggest that expression of ERRγ may be a marker of poor Tamoxifen response.
2008-11-01 | GSE12708 | GEO
Project description:Gene expression profiling of invasive breast cancer events from the tamoxifen prevention trial
2025-01-24 | E-GEOD-12665 | ExpressionAtlas
Project description:Tamoxifen response and resistance in invasive lobular breast cancer
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Project description:Endocrine response in invasive lobular carcinoma is characterized by unique estrogen-mediated gene expression and de novo tamoxifen resistance (MM134)
2025-01-24 | E-GEOD-50693 | ExpressionAtlas
Project description:Endocrine response in invasive lobular carcinoma is characterized by unique estrogen-mediated gene expression and de novo tamoxifen resistance (SUM44)
2025-01-24 | E-GEOD-50694 | ExpressionAtlas
Project description:Invasive Lobular Carcinoma (ILC), a distinct subtype of breast cancer is hallmarked by E-Cadherin loss, slow proliferation, and hormone receptor positivity. Major challenges in clinical management of ILC is advanced stage at diagnosis, resistance to endocrine therapy, a cornerstone in treating ILC patients, and late recurrence. To elucidate the mechanisms underlying endocrine resistance in ILC, we have generated ILC cell lines (MDA-MB-134-VI and SUM44PE) resistant to tamoxifen, a selective estrogen receptor modulator. Our study reveals methylation mediated silencing of ASS1 and demethylation restored ASS1 expression markedly reducing IC50 for tamoxifen. Treating TAMR cell with Decitabine, a demethylating agent, or Farudodstat, a pyrimidine biosynthesis inhibitor, markedly augmented efficacy of tamoxifen. Collectively, our study unveils ASS1 downregulation as a novel mechanism underlying acquired resistance to tamoxifen in ILC and establishes a metabolic link between ASS1 and nucleic acid biosynthesis. ASS1 can be a potential biomarker and a therapeutic target in tamoxifen resistant ILC patients, warranting further investigation.
2024-10-18 | MSV000096128 | MassIVE
Project description:One-third of all ER+ breast tumors treated with endocrine therapy fail to respond, and the remainder are likely to relapse in the future. Almost all data on endocrine resistance has been obtained in models of invasive ductal carcinoma (IDC). However, invasive lobular carcinomas (ILC) comprise up to 15% of newly diagnosed invasive breast cancers diagnosed each year and, while the incidence of IDC has remained relatively constant during the last 20 years, the prevalence of ILC continues to increase among postmenopausal women. We report a new model of Tamoxifen (TAM)-resistant invasive lobular breast carcinoma cells that provides novel insights into the molecular mechanisms of endocrine resistance. SUM44 cells express ER and are sensitive to the growth inhibitory effects of antiestrogens. Selection for resistance to 4-hydroxytamoxifen led to the development of the SUM44/LCCTam cell line, which exhibits decreased expression of estrogen receptor alpha (ERα) and increased expression of the estrogen-related receptor gamma (ERRγ). Knockdown of ERRγ in SUM44/LCCTam cells by siRNA restores TAM sensitivity, and overexpression of ERRγ blocks the growth-inhibitory effects of TAM in SUM44 and MDA-MB-134 VI lobular breast cancer cells. ERRγ-driven transcription is also increased in SUM44/LCCTam, and inhibition of activator protein 1 (AP1) can restore or enhance TAM sensitivity. These data support a role for ERRγ/AP1 signaling in the development of TAM resistance, and suggest that expression of ERRγ may be a marker of poor Tamoxifen response. Experiment Overall Design: Total RNA was extracted from sub-confluent T-25 cm^2 tissue culture flasks of SUM44 and LCCTam cells, then processed and arrayed. Microarray data quality was then assessed using several tools, including those recommended by Affymetrix and a series of additional QC measures. The Robust Multiple-Array Average (RMA) method was used to preprocess the raw gene expression data, as implemented in the Bioconductor project (http://bioconductor.org). We then isolated a reduced dimension dataset that included genes that exhibit â¥2 fold change, p<0.05 and genes with intensity â¥log2(10) in both SUM44 and SUM44/LCCTam groups. Data visualization before and after dimensionality reduction was facilitated by multidimensional scaling as estimated using Principal Component Analysis (PCA) and Discriminant Component Analysis (DCA), to ensure that the global structure of the data was not altered by dimensionality reduction procedures.
2008-11-13 | E-GEOD-12708 | biostudies-arrayexpress
Project description:Integrated Molecular Analysis of Tamoxifen-Resistant Invasive Lobular Breast Cancer Cells
| PRJNA379018 | ENA
Project description:Targeting the PI3K-AKT-mTOR pathway is a promising therapeutic strategy for breast cancer treatment. However, low response rates and the development of acquired resistance to PI3K-AKT-mTOR inhibitors remain major challenges for successful patient treatment. Here, we show that MYC activation is a central and clinically relevant mechanism of resistance to mTOR inhibitors (mTORi) in breast cancer. Multi-omic profiling of mouse invasive lobular carcinoma (ILC) tumors revealed recurrent focal Myc amplification in tumors that acquire resistance to the mTORi AZD8055. The gained MYC activity was significantly associated with biological processes linked to mTORi response. Specifically, MYC counteracted the translation inhibitory effect induced by mTORi by promoting the translation of ribosomal proteins. In vitro and in vivo induction of MYC conferred resistance to AZD8055 as well as the clinically approved mTORi everolimus, both in mouse models of ILC and human breast cancer models. Conversely, AZD8055-resistant ILC cells depended on MYC, as demonstrated by synergistic growth inhibition using mTORi and MYCi combination treatment. Notably, MYC status was significantly associated with poor response to everolimus therapy in metastatic breast cancer patients. Thus, MYC is a clinically relevant determinant of mTORi resistance that may guide the selection of breast cancer patients for mTOR targeted therapies.
2023-05-02 | PXD041927 | Pride
Project description:Invasive lobular breast cancer (ILC) is the second most common histological sub-type of breast cancer. Although the majority of ILC are strongly hormone receptor positive and are of low-intermediate grade, they present a number of clinical challenges. These challenges include limitations in physical exam and breast imaging for early detection, decreased response to chemotherapy and prospective evidence for differences in the benefit from specific adjuvant endocrine treatment regimens when compared to invasive ductal cancer (IDC). In addition to loss of e-cadherin, ILCs possess genetic alterations that are suggestive of a unique estrogen receptor(ER) axis, including an increase in the frequency of FOXA1 mutations and decrease in GATA3 truncating mutations. We performed a randomized Phase II clinical trial, Palbociclib and Endocrine therapy for Lobular breast cancer Preoperative Study (PELOP), in which patients were stratified by histological subtype and found that the magnitude of the difference between the benefit from letrozole compared tamoxifen is significantly higher in ILC versus IDC. To elucidate the mechanism underlying this divergent response we comprehensively studied the ER axis in experimental models of ILC and IDC and clinical samples and show that ILC harbors a unique ER transcriptional axis that stems from increased FOXA1 chromatin binding and an altered chromatin state. These findings provide insights to the unique pattern of response to endocrine treatment in ILC and mechanisms of resistance to endocrine treatment, and offer new treatment strategies to improve outcomes for patients with this breast cancer subtype."
2022-08-31 | GSE152512 | GEO