Dataset Information

Transcription profiling of human MCF7 cells after EGF, HRG stimulation

ABSTRACT: Sharing common ErbB/HER receptor signaling pathway, heregulin (HRG) induces differentiation of MCF-7 breast cancer cells while epidermal growth factor (EGF) elicits proliferation. Although the cell fate led by those two ligands was totally different, the gene expression profile in early transcription was unexpectedly qualitatively similar, suggesting that the gene expression in late transcription, not early transcription, may reflect a respect of ligand specificity. In this study, based on the data from time-course microarray of all human genes, we predicted and determined a series of transcription factors which may control HRG-specific timed-late transcription and cellular differentiation of MCF-7 cells. Validation analyses showed that one of activator protein 1 (AP-1) families appeared just after c-Fos expression, another AP-1 family partner, induced expression of another transcription factor through activation of AP-1 complex. Furthermore, expression of this transcription factors caused suppression of extracellular signal-regulated kinase (ERK) phosphorylation which is sustainedly regulated by HRG-initiated ErbB signaling. Overall, our analysis indicated an importance of formation of timed-transcriptional regulatory network and its function to control upstream signaling pathway through negative feedback for cellular differentiation. Experiment Overall Design: MCF7 human breast cancer cells were stimulated by the growth hormone (epidermal growth factor (EGF) or heregulin (HRG)). Control was set as non-treated cells.

ORGANISM(S): Homo sapiens

SUBMITTER: Hatakeyama Mariko

PROVIDER: S-ECPF-GEOD-13009 | biostudies-other |

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Using a chromatin immunoprecipitation-paired end diTag cloning and sequencing strategy, we mapped estrogen receptor alpha (ERalpha) binding sites in MCF-7 breast cancer cells. We identified 1,234 high confidence binding clusters of which 94% are projected to be bona fide ERalpha binding regions. Only 5% of the mapped estrogen receptor binding sites are located within 5 kb upstream of the transcriptional start sites of adjacent genes, regions containing the proximal promoters, whereas vast majority of the sites are mapped to intronic or distal locations (>5 kb from 5' and 3' ends of adjacent transcript), suggesting transcriptional regulatory mechanisms over significant physical distances. Of all the identified sites, 71% harbored putative full estrogen response elements (EREs), 25% bore ERE half sites, and only 4% had no recognizable ERE sequences. Genes in the vicinity of ERalpha binding sites were enriched for regulation by estradiol in MCF-7 cells, and their expression profiles in patient samples segregate ERalpha-positive from ERalpha-negative breast tumors. The expression dynamics of the genes adjacent to ERalpha binding sites suggest a direct induction of gene expression through binding to ERE-like sequences, whereas transcriptional repression by ERalpha appears to be through indirect mechanisms. Our analysis also indicates a number of candidate transcription factor binding sites adjacent to occupied EREs at frequencies much greater than by chance, including the previously reported FOXA1 sites, and demonstrate the potential involvement of one such putative adjacent factor, Sp1, in the global regulation of ERalpha target genes. Unexpectedly, we found that only 22%-24% of the bona fide human ERalpha binding sites were overlapping conserved regions in whole genome vertebrate alignments, which suggest limited conservation of functional binding sites. Taken together, this genome-scale analysis suggests complex but definable rules governing ERalpha binding and gene regulation. Experiment Overall Design: We used oligonucleotide expression microarrays (Affymetrix GeneChip U133 Plus 2.0) to identify estradiol (E2)-responsive genes in the estrogen-receptor positive breast cancer cell line, MCF7. MCF7 cells were grown to 30-50% confluency and exposed to 10 nM E2 (or vehicle only) at 12, 24, and 48 hours. Each timepoint was performed in triplicate (ie, biological replicates). Total RNA was isolated from cells using the Qiagen RNeasy kit, and 5 micrograms of total RNA was amplified, labeled and hybridized to the array according to the manufacturer’s protocols.

Dataset Information

Transcription profiling of human MCF7 cells after EGF, HRG stimulation

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets