Project description:Genome-wide association studies have identified a locus within the second intron of the FGFR2 gene that is consistently the most strongly associated with estrogen receptor-poisive breast cancer risk. 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. Previously, a systems biology approach was adopted to elucidate the regulatory networks operating in MCF-7 breast cancer cells in order to examine the role of FGFR2 in mediating risk. Here, the same approach has been employed using MCF-7 cells that have been treated with siRNA directed against FGFR2, in order to knock-down FGFR2 expression, to confirm that the differential gene expression that we see when FGF10 signalling is perturbed, on a background of estrogen signalling, is mediated via FGFR2 stimulation.
Project description:Genome-wide association studies have identified a locus within the second intron of the FGFR2 gene that is consistently the most strongly associated with estrogen receptor-poisive breast cancer risk. 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. Previously, a systems biology approach was adopted to elucidate the regulatory networks operating in MCF-7 breast cancer cells in order to examine the role of FGFR2 in mediating risk. Here, the same approach has been employed using a number of different estrogen receptor-positive breast cancer cell lines in order to see if the previous findings are reproducible and consistent in estrogen receptor-positive disease.
Project description:Estrogen signaling in breast cancer cells relies on long-range chromatin interactions connecting distal regulatory elements bound by the estrogen receptor 1 (ESR1) to target gene promoters. This ensures stimulus and subtype-specific transcriptional responses. Expanding on the function of CTCF and the cohesin complex in breast cancer, we demonstrate that the chromatin-looping factor ZNF143 binds the promoter of most early-response estrogen target genes connected to distal regulatory elements in ESR1-positive breast cancer cells. Its chromatin occupancy is unaffected by estrogen stimulation, supporting a stable three-dimensional genomic architecture within the early response to estrogen. Its loss abrogates the estrogen-induced transcriptional response and growth of breast cancer cells. When taking into account CTCF, ZNF143 and cohesin complex subunits, we show that chromatin-looping factors are genetically altered in over 20% of ESR1-positive primary breast tumors. Furthermore, the overexpression of ZNF143, CTCF and RAD21, a cohesin complex subunit, in ESR1-positive breast tumors associates with a worse clinical outcome. Overall, our results suggest that ZNF143 is a new critical effector of the estrogen response and highlights the contribution of the chromatin looping machinery to ESR1-positive breast cancer development. mRNA profiles of MCF-7 cells (siCtl or siZNF143) under vehicle (EtOH) or E2 (10 uM 17-beta oestradiol) stimulation
Project description:Studying transcription factor (TF) interactions and gene regulatory networks in breast cancer, we have recently identified two distinct and opposing clusters of TFs associated with estrogen receptor-positive and -negative breast cancer and breast cancer risk. The relative activity of these two groups of TFs has a dramatic effect on patient outcomes and is likely to influence the phenotypic plasticity observed in breast cancer. We have identified two novel interactors (NFIB and YBX1) of the estrogen receptor (ESR1) using Rapid Immunoprecipitation Mass Spectrometry of Endogenous Proteins (RIME), co-immunoprecipitation and microscopy experiments. Both NFIB and YBX1 are members of the group of risk TFs that oppose the activity of the risk TFs associated with estrogen receptor-positive disease, and we have demonstrated that they both repress the transcriptional activity of ESR1. Here, we examine the effect of NFIB and YBX1 overexpression on the transcriptome of an estrogen receptor-positive breast cancer cell line to see if these risk TFs are able to repress the ESR1 regulon and drive cells towards a less estrogen-dependent phenotype.
Project description:Estrogen signaling in breast cancer cells relies on long-range chromatin interactions connecting distal regulatory elements bound by the estrogen receptor 1 (ESR1) to target gene promoters. This ensures stimulus and subtype-specific transcriptional responses. Expanding on the function of CTCF and the cohesin complex in breast cancer, we demonstrate that the chromatin-looping factor ZNF143 binds the promoter of most early-response estrogen target genes connected to distal regulatory elements in ESR1-positive breast cancer cells. Its chromatin occupancy is unaffected by estrogen stimulation, supporting a stable three-dimensional genomic architecture within the early response to estrogen. Its loss abrogates the estrogen-induced transcriptional response and growth of breast cancer cells. When taking into account CTCF, ZNF143 and cohesin complex subunits, we show that chromatin-looping factors are genetically altered in over 20% of ESR1-positive primary breast tumors. Furthermore, the overexpression of ZNF143, CTCF and RAD21, a cohesin complex subunit, in ESR1-positive breast tumors associates with a worse clinical outcome. Overall, our results suggest that ZNF143 is a new critical effector of the estrogen response and highlights the contribution of the chromatin looping machinery to ESR1-positive breast cancer development. Examination of genome-wide ZNF143 binding in MCF-7 cells
Project description:Estrogen signaling in breast cancer cells relies on long-range chromatin interactions connecting distal regulatory elements bound by the estrogen receptor 1 (ESR1) to target gene promoters. This ensures stimulus and subtype-specific transcriptional responses. Expanding on the function of CTCF and the cohesin complex in breast cancer, we demonstrate that the chromatin-looping factor ZNF143 binds the promoter of most early-response estrogen target genes connected to distal regulatory elements in ESR1-positive breast cancer cells. Its chromatin occupancy is unaffected by estrogen stimulation, supporting a stable three-dimensional genomic architecture within the early response to estrogen. Its loss abrogates the estrogen-induced transcriptional response and growth of breast cancer cells. When taking into account CTCF, ZNF143 and cohesin complex subunits, we show that chromatin-looping factors are genetically altered in over 20% of ESR1-positive primary breast tumors. Furthermore, the overexpression of ZNF143, CTCF and RAD21, a cohesin complex subunit, in ESR1-positive breast tumors associates with a worse clinical outcome. Overall, our results suggest that ZNF143 is a new critical effector of the estrogen response and highlights the contribution of the chromatin looping machinery to ESR1-positive breast cancer development.
Project description:Estrogen signaling in breast cancer cells relies on long-range chromatin interactions connecting distal regulatory elements bound by the estrogen receptor 1 (ESR1) to target gene promoters. This ensures stimulus and subtype-specific transcriptional responses. Expanding on the function of CTCF and the cohesin complex in breast cancer, we demonstrate that the chromatin-looping factor ZNF143 binds the promoter of most early-response estrogen target genes connected to distal regulatory elements in ESR1-positive breast cancer cells. Its chromatin occupancy is unaffected by estrogen stimulation, supporting a stable three-dimensional genomic architecture within the early response to estrogen. Its loss abrogates the estrogen-induced transcriptional response and growth of breast cancer cells. When taking into account CTCF, ZNF143 and cohesin complex subunits, we show that chromatin-looping factors are genetically altered in over 20% of ESR1-positive primary breast tumors. Furthermore, the overexpression of ZNF143, CTCF and RAD21, a cohesin complex subunit, in ESR1-positive breast tumors associates with a worse clinical outcome. Overall, our results suggest that ZNF143 is a new critical effector of the estrogen response and highlights the contribution of the chromatin looping machinery to ESR1-positive breast cancer development.
Project description:Fibroblast Growth Factor (FGF) dependent signalling is frequently activated in cancer by a variety of different mechanisms. However, the downstream signal transduction pathways involved are poorly characterised. Here a quantitative differential phosphoproteomics approach, SILAC, is applied to identify FGF-regulated phosphorylation events in two triple- negative breast tumour cell lines, MFM223 and SUM52PE, that exhibit amplified expression of FGF receptor 2 (FGFR2) and are dependent on continued FGFR2 signalling for cell viability. Comparative Gene Ontology proteome analysis revealed that SUM52PE cells were enriched in proteins associated with cell metabolism and MFM223 cells enriched in proteins associated with cell adhesion and migration. FGFR2 inhibition by SU5402 impacts a significant fraction of the observed phosphoproteome of these cells. This study expands the known landscape of FGF signalling and identifies many new targets for functional investigation. FGF signalling pathways are found to be flexible in architecture as both shared, and divergent, responses to inhibition of FGFR2 kinase activity in the canonical RAF/MAPK/ERK/RSK and PI3K/AKT/PDK/mTOR/S6K pathways are identified. Inhibition of phosphorylation-dependent negative-feedback pathways is observed, defining mechanisms of intrinsic resistance to FGFR2 inhibition. These findings have implications for the therapeutic application of FGFR inhibitors as they identify both common and divergent responses in cells harbouring the same genetic lesion and pathways of drug resistance.
Project description:Comparison between Estrogen receptor positive and Estrogen receptor negative breast cancer samples Keywords: breast cancer type comparison