Project description:MCF-7 is an estrogen receptor-positive breast cancer cell line. This experiment is designed to study (1) the effect of estradiol (E2) exposure and (2) lysine methyltransferase 2B (KMT2B) knockdown in MCF-7 cells. Cells were grown for 72 hours prior to treatment with vehicle or 10 nM E2 for 4 and 24 hours. Additionally, to assess the effect of KMT2B knockdown, MCF-7 cells were transfected with KMT2B targeting siRNA or scrambled control siRNA in the absence or presence of E2. RNA were isolated using Trizol and hybridized to Affymetrix GeneChip Human Genome U133 Plus 2.0 array.
Project description:Genome-wide association studies for breast cancer have identified over 80 different risk regions in the genome, with the FGFR2 locus consistently identified as the most strongly associated locus. However, we know little about the mechanisms by which the FGFR2 locus mediates risk or the pathways in which multiple risk loci may combine to cause disease. Here we use a systems biology approach to elucidate the regulatory networks operating in breast cancer and examine the role of FGFR2 in mediating risk. Using model systems we identify FGFR2-regulated genes and, combining variant set enrichment and eQTL analysis, show that these are preferentially linked to breast cancer risk loci. Our results support the concept that cancer-risk associated genes cluster in pathways The data consists of 18 microarray samples after knocking down PTTG1 and SPDEF in MCF-7 cells. The data have been pre-processed in R using the Beadarray package, and are presented in the form of log2 expression values. The experiment was carried out on Humanv4 BeadChips arrays interrogating 48107 randomly-distributed bead-types, and in this experiment there was a mean of 22 beads per bead-type (Standard Deviation of 5)
Project description:Using a transcriptional network derived from 2000 breast cancer gene expression profiles we identify the master regulators (MRs) of FGFR2 signalling. To validate the identified regulons, we examined whether there was enrichment of TF binding near the transcription start sites (TSS) of genes found in the regulons of a particular MR. For ESR1 and SPDEF, ChIP-seq experiments were performed in MCF-7 cells, while existing data was analysed for FOXA1 (Hurtado et al. Nature Genetics, 43:27–33, 2010) and GATA3 (Theodorou, et al., Genome Res 23: 12-22, 2013). ChIP-seq experiments were performed on three biological replicates per each transcription factor. For each sample, 36bp single-end reads were obtained. Peak regions were identified in all ChIP-seq TF data sets using the peak caller algorithm MACS (Zhang et al., Genome Biology, 9(9):R137, 2008) with default parameters.
Project description:To examine the role of PSF and NONO in estrogen-dependent breast cancer, MCF-7 cells were treated with siRNA targeting PSF, NONO or control siRNA (siControl). Microarray analysis revealed PSF- or NONO-regulated genes in MCF-7 cells.
Project description:We investigated the functions/pathways affected by SPEN knockdown in breast cancer by global expression profiling in a cell model, where the human breast cancer cell line, MCF-7, were transfected with an shRNA targeting SPEN mRNA.
Project description:Despite improvements in therapeutic strategies for treating breast cancers, tumor relapse and chemoresistance remain major issues in patient outcomes. Indeed, cancer cells display a metabolic plasticity allowing a quick adaptation to tumoral microenvironment and to cellular stresses induced by chemotherapy. Recently, long non-coding RNA molecules (lncRNAs) have emerged as important regulators of cellular metabolic orientation. In the present study, we addressed the role of the long non-coding RNA molecule (lncRNA) SAMMSON on the metabolic reprogramming and chemoresistance of MCF-7 breast cancer cells resistant to doxorubicin (MCF-7dox). Our results showed an overexpression of SAMMSON in MCF-7dox compared to doxorubicin-sensitive cells (MCF-7). Silencing of SAMMSON expression by siRNA in MCF-7dox cells resulted in a metabolic rewiring with improvement of oxidative metabolism, decreased mitochondrial ROS production, increased mitochondrial replication, transcription and translation and an attenuation of chemoresistance. These results highlight the role of SAMMSON in the metabolic adaptations leading to the development of chemoresistance in breast cancer cells. Thus, targeting SAMMSON expression levels represents a promising therapeutic route to circumvent doxorubicin resistance in breast cancers.
Project description:To examine the role of long non-coding RNA TMPO-AS1 in breast cancer, MCF-7 cells were treated with siRNAs targeting TMPO-AS1 (siTMPO-AS1) or control siRNA (siControl). TMPO-AS1 was shown to closely associate with estrogen signaling pathway.
Project description:To examine the role of SCFD2 in breast cancer, MCF-7 cells were treated with siRNAs targeting SCFD2 (siSCFD2) or control siRNA (siControl). SCFD2 silencing represses expressions of anti-apoptotic genes which are positively associated with shorter relapse-free survival in ER-positive breast cancer patients. These results reveal the clinical and functional significance of SCFD2 and its targets in hormone-dependent breast cancer. SCFD2 may be applied to the cancer management as a promising diagnostic and therapeutic target.
Project description:Using a siRNA screen we identified the histone demethylase enzyme KDM3A as a potential positive regulator of ER signalling in breast cancer. To interrogate the full extent of KDM3A regulation on ER signalling we assessed basal and estrogen (E2)- stimulated global gene expression changes in KDM3A-depleted MCF-7 cells by microarray analysis using the Illumina Human HT12 Version 4 BeadChip array. We identified ER regulated genes affected by KDM3A knockdown and determined that KDM3A is required for ER recruitment to estrogen response elements in the promotors of ER regulated genes. We also identified that KDM3A regulates expression of a number of genes involved in proliferation and that knockdown of KDM3A inhibits ER positive breast cancer cell growth. MCF-7 cells were transfected with either a non-silencing scrambled control siRNA (siSCR) or a KDM3A targeting siRNA (siKDM3A-B) using Lipfectamine RNAiMAX (Invitrogen) to a final concentration of 25 nM in steroid depleted conditions. Cells were grown for 48 hours prior to treatment with vehicle or 10 nM E2 for 4 hours before RNA extraction using TRIzol (Ambion, Life Technologies) and hybridization of triplicate samples to an Illumine HT-12 v4 BeadChip array. One sample failed due to low amounts of cRNA and was therefore not included in the analysis (siKDM3A + E2 Replicate 3). The array for replicates 1 and 2 was performed in August 2013 (Array 1) and replicate 3 in August 2014 (Array 2). When processing the data Array 2 was normalized to Array 1.
Project description:The goals of this study were to identify LIN28 downstream gene targets in breast cancer cells. We use a subclone of the MCF-7 breast cancer cell line, MCF-7M as our model system. Methods: mRNA profiles from MCF-7M breast cancer cells treated with siRNA against non-targeting control (NT), LIN28, hnRNP A1, LIN28 and hnRNPA1 (LIN28A1) for 72 hrs were generated by deep sequencing, in duplicate, using Illumina HiSeq 2000. The sequence reads that passed quality filters were analyzed at the transcript isoform level with two methods: Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Results: Using an optimized data analysis workflow, we mapped over 200 million sequence reads per sample to the human genome (build h19). Each of the four groups had two biological replicates. We developed a custom method to identify alternative splicing events and identified 111 genes with significant (FDR<0.05) differential splicing for LIN28 depleted cells compared to non-targeting siRNA control, as well as 249 and 182 genes for hnRNP A1 and LIN28A1 respectively. RNA-seq data were validated with by qRT–PCR analysis of a subset of genes. Conclusions: Results reveal that LIN28 regulates alternative splicing and steady state mRNA expression of genes implicated in aspects of breast cancer biology. Notably, cells lacking LIN28 undergo significant isoform switching of the ENAH gene, resulting in a decrease in the expression of ENAH exon 11a isoform. Expression of ENAH isoform 11a has been shown to be elevated in breast cancers that express HER2. mRNA profiles of MCF-7M cells treated with siRNA for NT control, LIN28, hnRNP A1, and LIN28 plus hnRNP A1 (A1) (LIN28A1) were generated by deep sequencing, in duplicate, using Illumina HiSeq 2000