BASP1 modifies the Tamoxifen response
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE78199 | GEO | 2016/08/01
SECONDARY ACCESSION(S): PRJNA312917
REPOSITORIES: GEO
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Project description:We report that WT1 transcriptional repressor protein BASP1 interacts with oestrogen receptor alpha (Erα), and interaction which in enhanced in the presence of Tamoxifen. We utilised RNASeq to identify common BASP1 and ERα target genes as well as Tamoxifen responsive genes that are altered in the absence of BASP1. Total mRNA sequencing analysis of MCF7 cells treated with either siRNA against BASP1 or negative control siRNA, with and without Tamoxifen treatment. Each experiment was performed in triplicate.
2016-08-01 | E-GEOD-78199 | biostudies-arrayexpress
Project description:Approximately 40% ERα-positive breast cancer patients suffer from therapeutic resistance to tamoxifen. Although reduced ERα level is the major cause of tamoxifen resistance, the underlying mechanisms remain elusive. Here, we report that FRMD8 raises the level of ERα at both transcriptional and post-translational layers. FRMD8 deficiency in MMTV-Cre+; Frmd8fl/fl; PyMT mice accelerates mammary tumor growth and loss of luminal phenotype, and confers tamoxifen resistance. Single-cell RNA profiling reveals that Frmd8 loss decreases the proportion of hormone-sensing differentiated epithelial cells and downregulates the levels of ERα. Mechanically, on one hand, loss of FRMD8 inhibits ESR1 transcription via suppressing the expression of FOXO3A, a transcription factor of ESR1. On the other hand, FRMD8 interacts both with ERα and UBE3A, and disrupts the interaction of UBE3A with ERα, thereby blocking UBE3A-mediated ERα degradation. In breast cancer patients, FRMD8 gene promoter is found hypermethylated and low level of FRMD8 predicts poor prognosis. Therefore, FRMD8 is an important regulator of ERα and may control therapeutic sensitivity to tamoxifen in ERα-positive breast cancer patients.
2025-04-09 | GSE244582 | GEO
Project description:We have analysed the dynamic between WT1 and BASP1 in the regulation of gene expression in myelogenous leukaemia K562 cells. Our analysis reveals that BASP1 is a significant regulator of WT1 that is recruited to WT1-binding sites and suppresses WT1-mediated transcriptional activation at several WT1 target genes. We found that WT1 and BASP1 can divert the differentiation program of K562 cells to a non-blood cell type following induction by the phorbol ester PMA. Cell lines were generated expressing the BASP1 gene from the vector pcDNA3. Array analysis was performed on 4 conditions: cells expressing BASP1 and controls, in the absence and presence of Phorbol 12-myristate 13-acetate (PMA).
2010-12-18 | E-MEXP-2573 | biostudies-arrayexpress
Project description:The molecular explanation for tamoxifen serving as a breast cancer treatment but displaying partial estrogenic in the uterus is not known. Previously, we reported that differential promoter context and cofactor recruitment contribute to the tissue specificity of tamoxifen. Here, we investigated the genomic basis for the partial oestrogenic activity of tamoxifen in the endometrium. We showed that tamoxifen not only affects the rate of transcription of oestrogen target genes but also targets a unique set of genes. Since oestrogen and tamoxifen are both able to bind to oestrogen receptors (ERs) and because both promote endometrial carcinogenesis, we hypothesized that the molecular effectors for ERs in endometrial carcinogenesis most likely reside in genes that are commonly targeted by oestrogen and tamoxifen. Among those target genes, we identified a paired-box gene PAX2 that is critically involved in cell proliferation and carcinogenesis in the endometrium. Our experiments also demonstrated that PAX2 is activated by oestrogen and tamoxifen in endometrial carcinomas but not in normal endometrium, and this activation is associated with cancer-linked hypomethylation of the PAX2 promoter. Keywords: actions of tamoxifen
2005-07-29 | GSE3013 | GEO
Project description:Tamoxifen Resistant (TR) gene profile from Breast cancer cell lines T47D and ZR75-1 with their oestrogen-deprieved conterparts were analysed for gene associated with TR. We used Microarray Affymetrix HU133plus 2.0 chips for gene expression of TR cell lines, normalised them against GEO data available for normal T47D (GSM70667) and ZR75-1 (GSM70668). We grew parental breast cancer cell lines in tamoxifen containing media (0.1 microM) for 6 months and labelled them tamoxifen resistant (TR). Oestrogen-Deprieved cells were grown in charcoal-stripped media for 6 months then tamoxifen (0.1 microM) was added to the media and cells maintained a further 6 months and termed Oestrogen deprieved-tamoxifen resistant (ODTR) .
2010-12-31 | E-GEOD-22664 | biostudies-arrayexpress
Project description:About one-third of oestrogen receptor alpha- positive breast cancer patients treated with tamoxifen relapse. Here we identify the nuclear receptor retinoic acid receptor alpha as a marker of tamoxifen resistance. Using quantitative mass spectrometry-based proteomics, we show that retinoic acid receptor alpha protein networks and levels differ in a tamoxifen-sensitive (MCF7) and a tamoxifen-resistant (LCC2) cell line. High intratumoural retinoic acid receptor alpha protein levels also correlate with reduced relapse-free survival in oestrogen receptor alpha-positive breast cancer patients treated with adjuvant tamoxifen solely. A similar retinoic acid receptor alpha expression pattern is seen in a comparable independent patient cohort. An oestrogen receptor alpha and retinoic acid receptor alpha ligand screening reveals that tamoxifen-resistant LCC2 cells have increased sensitivity to retinoic acid receptor alpha ligands and are less sensitive to oestrogen receptor alpha ligands compared with MCF7 cells. Our data indicate that retinoic acid receptor alpha may be a novel therapeutic target and a predictive factor for oestrogen receptor alpha-positive breast cancer patients treated with adjuvant tamoxifen. Peptide and protein identification data set 1: Peptide identification from the MALDI-TOF/TOF data was carried out using the Paragon algorithm in the ProteinPilot 2.0 software package (Applied Biosystems) 46. Default settings for a 4800 instrument were used (i.e., no manual settings for mass tolerance was given). The following parameters were selected in the analysis method: iTRAQ 4plex peptide labelled as sample type, MMTS as alkylating agent of cysteine, trypsin as digesting enzyme, 4800 as instrument, gel based ID and Urea denaturation as special factors, biological modifications as ID focus, and thorough ID as search effort. Peptide identification from the Q-TOF data was carried out using the Spectrum Mill Protein Identification software (Agilent). Data was extracted between MH+ 600 and 4000 Da (Agilent's definition). Scans with the same precursor m/z 90 sec, 0.05 m/z matching with a minimum of 20 peaks in MS2 were merged. Peptide and protein identification data set 2: Proteome discoverer 1.3 with sequest-percolator was used for protein identification. Precursor mass tolerance was set to 10 ppm and for fragments 0.8 Da and 0.02 Da were used for detection in the linear iontrap and the orbitrap, respectively. Oxidized methionine and phosphorylation on S,T and Y was set as dynamic modifications, and carbamidomethylation, N-terminal 8plex iTRAQ, and lysyl 8plex iTRAQ as fixed modifications. Spectra were matched to ensembl 68 limited to human protein sequences, and results were filtered to 1% FDR.
2013-07-24 | PXD000281 | Pride
Project description:Tamoxifen, a small molecule inhibitor that binds the Estrogen Receptor alpha (ERα), blocks breast cancer progression while increasing the risk for endometrial cancer. In this study, we assessed genome-wide ERα-chromatin interactions in surgical specimens of endometrial tumors from patients who were previously treated for breast cancer with tamoxifen, and endometrial tumors from patients who were treated without tamoxifen. We compared ERα and signal at differential ERα sites in endometrial tumors of nine patients who received tamoxifen with endometrial tumors with six patients who never used tamoxifen. In addition, we performed H3K27ac (a marker for activity) ChIPs on the above mentioned endometrial tumors, and assed this signal at differential ERα sites. Compared to endometrial tumors of non-users, tamoxifen-associated endometrial tumors exposed higher H3K27ac intensities at ERα sites that are enriched in tamoxifen-associated endometrial tumors. Four tamoxifen-associated endometrial tumors that we used in our analysis have been previously published as Tumor A, B, D, and E in GSE81213.
2017-03-06 | GSE94031 | GEO
Project description:Tamoxifen, a small molecule inhibitor that binds the Estrogen Receptor alpha (ERα), blocks breast cancer progression while increasing the risk for endometrial cancer. In this study, we assessed genome-wide ERα-chromatin interactions in surgical specimens of endometrial tumors from patients who were previously treated for breast cancer with tamoxifen, and endometrial tumors from patients who were treated without tamoxifen. We compared ERα and signal at differential ERα sites in endometrial tumors of nine patients who received tamoxifen with endometrial tumors with six patients who never used tamoxifen. In addition, we performed H3K27ac (a marker for activity) ChIPs on the above mentioned endometrial tumors, and assed this signal at differential ERα sites. Compared to endometrial tumors of non-users, tamoxifen-associated endometrial tumors exposed higher H3K27ac intensities at ERα sites that are enriched in tamoxifen-associated endometrial tumors. Four tamoxifen-associated endometrial tumors that we used in our analysis have been previously published as Tumor A, B, D, and E in GSE81213.
2017-03-07 | GSE94523 | GEO
Project description:Estrogen receptor alpha (ERα) is highly expressed in most breast cancers. Consequently, ERα modulators, such as tamoxifen, are successful in breast cancer treatment, although tamoxifen resistance is commonly observed. While tamoxifen resistance may be caused by altered ERα signaling, the molecular mechanisms regulating ERα signaling and tamoxifen resistance are not entirely clear. Here, we found that PAK4 expression was consistently correlated to poor patient outcome in endocrine treated and tamoxifen-only treated breast cancer patients. Importantly, while PAK4 overexpression promoted tamoxifen resistance in MCF-7 human breast cancer cells, pharmacological treatment with a group II PAK (PAK4, 5, 6) inhibitor, GNE-2861, sensitized tamoxifen resistant MCF-7/LCC2 breast cancer cells to tamoxifen. Mechanistically, we identified a regulatory positive feedback loop, where ERα bound to the PAK4 gene, thereby promoting PAK4 expression, while PAK4 in turn stabilized the ERα protein, activated ERα transcriptional activity and ERα target gene expression. Further, PAK4 phosphorylated ERα-Ser305, a phosphorylation event needed for the PAK4 activation of ERα-dependent transcription. In conclusion, PAK4 may be a suitable target for perturbing ERα signaling and tamoxifen resistance in breast cancer patients.
2015-12-12 | GSE73320 | GEO
Project description:Estrogen receptor α (ERα) is a key transcriptional regulator in the majority of breast cancers. ERα-positive patients are frequently treated with tamoxifen, but resistance is common. In this study, we refined a previously identified 111-gene outcome prediction-classifier, revealing FEN1 as the strongest determining factor in ERα-positive patient prognostication. FEN1 levels were predictive of outcome in tamoxifen-treated patients, and FEN1 played a causal role in ERα-driven cell growth. FEN1 impacted the transcriptional-activity of ERα by facilitating coactivator recruitment to the ERα transcriptional complex. FEN1 blockade induced proteasome-mediated degradation of activated ERα, resulting in loss of ERα-driven gene expression and eradicated tumor cell proliferation. Finally, a high-throughput 465,195 compound screen identified a novel FEN1 inhibitor, which effectively blocked ERα-function and inhibited proliferation of tamoxifen-resistant cell lines as well as ex-vivo cultured ERα-positive breast tumors. Collectively, these results provide therapeutic proof-of-principle for FEN1 blockade in tamoxifen-resistant breast cancer.
2020-06-01 | GSE95302 | GEO