Project description:We report mRNA profiles of human breast cancer cell lines, MCF7 parental, and MCF7-derived tamoxifen resistant cell lines MCF7-TR1 and MCF7-TR2.
Project description:We aim to the investigate the role of tamoxifen in breast cancer progression. LCC2 and MCF-7 cells were used as the resistant and sensitive model.
Project description:Estrogen signaling pathway is critical for breast cancer development and has remained the major adjuvant therapeutic target for this disease. Tamoxifen has been used in clinic for many years to treat ER-positive breast cancer. However a great many (30%) suffer relapse due to drug resistance. In this study, the bromodomain inhibitor JQ1 was found to down-regulate ERalpha gene expression and have anti-tumor effect in cultured tamoxifen-resisant breast cancer cells. We used microarrays to detail the global programme of gene expression in tamoxifen-resistant MCF7 cells treated with the bromodomain inhibitor JQ1. Tamoxifen-resistant breast cancer MCF7 cells were treated with DMSO (vehicle) or JQ1 (0.2 uM) for 24 hours before total RNA was purified for microarray. Each sample was triplicated.
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.
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.
Project description:Estrogen signaling pathway is critical for breast cancer development and has remained the major adjuvant therapeutic target for this disease. Tamoxifen has been used in clinic for many years to treat ER-positive breast cancer. However a great many (30%) suffer relapse due to drug resistance. In this study, the bromodomain inhibitor JQ1 was found to down-regulate ERalpha gene expression and have anti-tumor effect in cultured tamoxifen-resisant breast cancer cells. We used microarrays to detail the global programme of gene expression in tamoxifen-resistant MCF7 cells treated with the bromodomain inhibitor JQ1.