Histone H3 Lysine4 Acetylation-Methylation Dynamics Define Breast Cancer Subtypes [ChIP-seq]
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ABSTRACT: The molecular signature at histone H3K4 involved in epigenetic regulation of normal (MCF10A) and transformed (MCF7, MDA-MB-231) breast cells using ChIP-Seq technology. This study examines the dynamic distribution of H3K4me3 and H3K4ac histone modification associated with active chromatin to provide an understanding of the changes in epigenetic regulation associated with the unique breast cancer subtypes.
Project description:The molecular signature at histone H3K4 involved in epigenetic regulation of normal (MCF10A) and transformed (MCF7, MDA-MB-231) breast cells using ChIP-Seq technology. This study examines the dynamic distribution of H3K4me3 and H3K4ac histone modification associated with active chromatin to provide an understanding of the changes in epigenetic regulation associated with the unique breast cancer subtypes. H3K4me3 and H3K4ac histone modification study in normal (MCF10A) and transformed (MCF7, MDA-MB-231) breast cells using ChIP-Seq technology
Project description:The onset and progression of breast cancer are linked to genetic and epigenetic changes that alter the normal programming of cells. Epigenetic modifications of DNA and histones contribute to chromatin structure that results in the activation or repression of gene expression. Several epigenetic pathways have been shown to be highly deregulated in cancer cells. Targeting specific histone modifications represents a viable strategy to prevent oncogenic transformation, tumor growth or metastasis. Methylation of histone H3 lysine 4 has been extensively studied and shown to mark genes for expression; however this residue can also be acetylated and the specific function of this alteration is less well known. To define the relative roles of histone H3 methylation (H3K4me3) and acetylation (H3K4ac) in breast cancer, we determined genomic regions enriched for both marks in normal-like (MCF10A), transformed (MCF7) and metastatic (MDA-MB-231) cells using a genome-wide ChIP-Seq approach. Our data revealed a genome-wide gain of H3K4ac associated with both early and late breast cancer cell phenotypes, while gain of H3K4me3 was predominantly associated with late stage cancer cells. Enrichment of H3K4ac was overrepresented at promoters of genes associated with cancer-related phenotypic traits, such as estrogen response and epithelial-to-mesenchymal transition pathways. Our findings highlight an important role for H3K4ac in predicting epigenetic changes associated with early stages of transformation. In addition, our data provide a valuable resource for understanding epigenetic signatures that correlate with known breast cancer-associated oncogenic pathways. RNA-Seq of cell lines MCF10A, MCF7 and MDA-MB-231.
Project description:The molecular signature at histone H3K4me3 and H3K27me3 involved in epigenetic regulation of normal (MCF10A) and transformed (MCF7, MDA-MB-231) breast cells using ChIP-Seq technology. This study examines the dynamic distribution of H3K4me3, associated with active chromatin, and H3K27me3, associated with repressed chromatin, histone modifications to provide an understanding of the changes in epigenetic regulation associated with the unique breast cancer subtypes.
Project description:The molecular signature at histone H3K4me3 and H3K27me3 involved in epigenetic regulation of normal (MCF10A) and transformed (MCF7, MDA-MB-231) breast cells using ChIP-Seq technology. This study examines the dynamic distribution of H3K4me3, associated with active chromatin, and H3K27me3, associated with repressed chromatin, histone modifications to provide an understanding of the changes in epigenetic regulation associated with the unique breast cancer subtypes. histone H3K4me3 and H3K27me3 ChIP-seq normal (MCF10A) and transformed (MCF7, MDA-MB-231) breast cells Please note that the 'H3K4me3' and 'input' data are duplicated records of the samples represented in GSE69377 for the convenient retrieval of the complete raw data from SRA.
Project description:The onset and progression of breast cancer are linked to genetic and epigenetic changes that alter the normal programming of cells. Epigenetic modifications of DNA and histones contribute to chromatin structure that results in the activation or repression of gene expression. Several epigenetic pathways have been shown to be highly deregulated in cancer cells. Targeting specific histone modifications represents a viable strategy to prevent oncogenic transformation, tumor growth or metastasis. Methylation of histone H3 lysine 4 has been extensively studied and shown to mark genes for expression; however this residue can also be acetylated and the specific function of this alteration is less well known. To define the relative roles of histone H3 methylation (H3K4me3) and acetylation (H3K4ac) in breast cancer, we determined genomic regions enriched for both marks in normal-like (MCF10A), transformed (MCF7) and metastatic (MDA-MB-231) cells using a genome-wide ChIP-Seq approach. Our data revealed a genome-wide gain of H3K4ac associated with both early and late breast cancer cell phenotypes, while gain of H3K4me3 was predominantly associated with late stage cancer cells. Enrichment of H3K4ac was overrepresented at promoters of genes associated with cancer-related phenotypic traits, such as estrogen response and epithelial-to-mesenchymal transition pathways. Our findings highlight an important role for H3K4ac in predicting epigenetic changes associated with early stages of transformation. In addition, our data provide a valuable resource for understanding epigenetic signatures that correlate with known breast cancer-associated oncogenic pathways.
Project description:Methylation of histone H3 lysine 4 (H3K4me) is an evolutionarily conserved modification whose role in the regulation of gene expression has been extensively studied. In contrast, the function of H3K4 acetylation (H3K4ac) has received little attention because of a lack of tools to separate its function from that of H3K4me. Here we show that, in addition to being methylated, H3K4 is also acetylated in budding yeast. Genetic studies reveal that the histone acetyltransferases (HATs) Gcn5 and Rtt109 contribute to H3K4 acetylation in vivo. Whilst removal of H3K4ac from euchromatin mainly requires the histone deacetylase (HDAC) Hst1, Sir2 is needed for H3K4 deacetylation in heterochomatin. Using genome-wide chromatin immunoprecipitation (ChIP), we show that H3K4ac is enriched at promoters of actively transcribed genes and located just upstream of H3K4 tri-methylation (H3K4me3), a pattern that has been conserved in human cells. We find that the Set1-containing complex (COMPASS), which promotes H3K4me2 and -me3, also serves to limit the abundance of H3K4ac at gene promoters. In addition, we identify a group of genes that have high levels of H3K4ac in their promoters and are inadequately expressed in H3-K4R, but not in set1 mutant strains suggesting that H3K4ac plays a positive role in transcription. Our results reveal a novel regulatory feature of promoter-proximal chromatin, involving mutually exclusive histone modifications of the same histone residue (H3K4ac and H3K4me).
Project description:Current approaches to menopausal hormone therapy consist of compounds which provide tissue specific beneficial effects while working to minimize any increase in cancer risk associated with replacement therapy. In this study, an examination of the genomic distribution of histone modification and expression changes in two breast epithelial cell lines, the normal MCF10A cell line and the MCF-7 breast cancer cell line, upon treatment with several of the current therapies used for treating post-menopausal symptoms is presented. Analysis of the observed changes upon treatment with either 17-estradiol (E2), a combined treatment with the top 10 most abundant Premarin chemical equivalents (EC10), the non-steroidal SERM, Bazadoxifene (BZA) and the TSEC; BZA combined with EC10 (Duavee) or BZA combined with E2 provides evidence of expression changes in genes involved in DNA replication, nucleosome assembly, RNA-splicing and processing, biological regulation and cell signaling, and many of the known steroid response genes. There were distinct global changes in chromatin states observed that were specific to each of the breast epithelial cell type normal, basal MCF10A and ESR/PGR positive luminal breast cancer MCF7 cell lines and selective changes observed upon treatment with each of the treatment groups. Specifically, we observed a global loss of H3K4ac upon treatment with BZA. These changes were observed in both ESR1 bound and non-bound regions suggesting modifications in both promoters and enhancer regions. The levels of H3K4ac upon treatment of BZA showed a decrease below basal non-treated H3K4ac levels in MCF7. There was an increase observed with E2 and EC10 treatment in MCF7 that was mitigated by the addition of BZA to either steroid as a combined treatment. This study provides a better understanding of the role of epigenetic modifications in endocrine responsiveness and provides evidence of an improved therapeutic profile for combined TSEC compounds for treating and managing the overall physiological effects of declining estrogen.