ABSTRACT: Chromatin immuno-precipitation using SUMO2 (Life Technologies) antibody in MCF10A cell line, treated with epidermal growth factor for 30 minutes.
Project description:Sequencing of total RNA and polysomal RNA of two cell lines, MCF7 (tumoral) and MCF10A (non-tumoral) Polysomal and total RNA was prepared from biological triplicates from the two cell lines. For each biological triplicate sub-confluent cell monolyers were lysed to produce cytoplasmic extracts. Half of each extract was fractionated on a sucrose gradient and the polysomal fraction recovered. Polysomal-associated RNA was recovered by Trizol extraction. From the second half of each sample total cyoplasmic RNA was recovered (Trizol extraction).
Project description:Although technological advances now allow increased tumor profiling, a detailed understanding of the mechanisms leading to the development of different cancers remains elusive. Our approach towards understanding the molecular events that lead to cancer is to characterize changes in transcriptional regulatory networks between normal and tumor tissue. Because enhancer activity is thought to be critical in regulating cell fate decisions, we have focused our studies on distal regulatory elements and transcription factors that bind to these elements. Using DNA methylation data, we identified more than 25,000 enhancers that are differentially activated in breast, prostate, and kidney tumor tissues, as compared to normal tissues. We then developed an analytical approach called TENET (Tracing Enhancer Networks using Epigenetic Traits) that correlates DNA methylation levels at enhancers with gene expression to identify more than 800,000 genome-wide links from enhancers to genes and from genes to enhancers. We found more than 1,200 transcription factors to be involved in these tumor-specific enhancer networks. We further characterized several transcription factors linked to a large number of enhancers in each tumor type, including GATA3 in non-basal breast tumors, HOXC6 and DLX1 in prostate tumors, and ZNF395 in kidney tumors. We showed that HOXC6 and DLX1 are associated with different clusters of prostate tumor-specific enhancers and confer distinct transcriptomic changes upon knockdown in C42B prostate cancer cells. We also discovered de novo motifs enriched in enhancers linked to ZNF395 in kidney tumors. Our studies characterized tumor-specific enhancers and revealed key transcription factors involved in enhancer networks for specific tumor types and subgroups. Our findings, which include a large set of identified enhancers and transcription factors linked to those enhancers in breast, prostate, and kidney cancers, will facilitate understanding of enhancer networks and mechanisms leading to the development of these cancers. Examination of FAIRE and ChIP assays in prostate and breast epithelial cells. RNA-seq assays in C42B, prostate cancer cell line after knocking down of TFs (HOXC6, DLX1).
Project description:Gene expression signatures encompassing dozens to hundreds of genes have been associated with many important parameters of cancer, but mechanisms of their control are largely unknown. Here we present a method based on genetic linkage that can prospectively identify functional regulators driving large-scale transcriptional signatures in cancer. Using this method we show that the wound response signature, a poor-prognosis expression pattern of 512 genes in breast cancer, is induced by coordinate amplifications of MYC and CSN5 (also known as JAB1 or COPS5). This information enabled experimental recapitulation, functional assessment and mechanistic elucidation of the wound signature in breast epithelial cells. Computed
Project description:Circular RNAs (circRNAs) are widespread circular forms of non-coding RNAs with largely unknown function. Because stimulation of mammary cells with the epidermal growth factor (EGF) leads to dynamic changes in the abundance of both coding and non-coding RNA molecules, and culminates in the acquisition of a robust migratory phenotype, this cellular model might disclose functions of circRNAs. Here we show that circRNAs of EGF-stimulated mammary cells are stably expressed, while mRNAs and micro-RNAs change within minutes. In general, the circRNAs we detected are relatively long-lived and weakly expressed. Interestingly, they are almost ubiquitously co-expressed with the corresponding linear transcripts, and the respective, shared promoter regions are more active compared to genes producing linear isoforms only. These findings imply that altered abundance of circRNAs, unlike changes in the levels of other RNAs, might not play critical roles in signaling cascades and downstream transcriptional networks that rapidly commit cells to specific outcomes. Detection of circRNAs from RNA-Seq â triplicate
Project description:We aimed to identify microRNAs that are regulated by YAP in human mammary epithelial cells. We utilized deep sequencing technology to identify microRNAs that are induced by YAP overexpression and repressed by YAP knockdown.
Project description:Oncogenic levels of Myc expression sensitize cells to multiple apoptotic stimuli and this protects long-lived organisms from cancer development. How cells discriminate physiological from supra-physiological levels of Myc is largely unknown. Here we show that induction of apoptosis by Myc in breast epithelial cells requires association of Myc with Miz1. Gene expression and ChIP-sequencing experiments show that oncogenic levels of Myc, but not of MycV394D, a point mutant that does not bind Miz1, recruit Miz1 to core promoters and enable binding of Myc/Miz1 complexes to low-affinity target sites, correlating with repression of a specific set of target genes. Repressed genes encode proteins involved in cell adhesion, migration and wound healing; their promoters are enriched for binding sites of the serum response (SRF) factor. Restoring SRF activity attenuates Myc-induced apoptosis in response to glutamine starvation, exposure to Trail and to DNA damage. We propose that supra-physiological levels of Myc engage Miz1 in repressive DNA binding complexes and suppress transcriptional progress. MIZ1, MYC-ER and MYC-ERVD ChIP-Seq with 10E2 and HC20 anti-ERalpha antibodies in MCF10A cells, performed on an Illumina IIx Genome Analyzer. Input sample is accessioned as GSM1423726.
Project description:The identification of the glucocorticoid receptor cistrome in a conditionally immortalized human podocyte cell line developed by transfection with the temperature-sensitive SV40-T gene