Project description:Promoter methylation was assayed in a number of breast cancer and control normal samples along with the effects of 5'-aza-2'-deoxycytidine on breast cancer cell line transcriptomes. Aberrant promoter hypermethylation is frequently observed in cancer. The potential for this to contribute to tumour development depends on whether the genes affected are repressed because of their methylation. Many aberrantly methylated genes play important roles in development and are bivalently marked in ES cells suggesting that their aberrant methylation may reflect developmental processes. We investigated this possibility by analysing promoter methylation in 19 breast cancer cell lines, 10 normal tissues and 47 primary breast tumours. In order to determine the role of DNA methylation in silencing genes in breast cancer, we also examined the effects of the demethylating agent 5-aza-2?-deoxycytidine on gene expression in 3 breast cancer cell lines and HCT116 cells. Gene expression changes were also assayed in the DNA methyltransferase deficient HCT116 DKO cell line. Our findings implicate aberrant DNA methylation as a marker of cell lineage rather than tumour progression and suggest that, in most cases, it does not cause the repression with which it is associated. A number of human breast cancer cell lines, breast tumours and normal tissues were analysed on Illumina Infinium Methylation27 Beadchips to assay promoter methylation. Selected cell lines were analysed on expression arrays before and after treatment with 5-aza-2'-deoxycytidine.
Project description:Promoter methylation was assayed in a number of breast cancer and control normal samples along with the effects of 5'-aza-2'-deoxycytidine on breast cancer cell line transcriptomes. Aberrant promoter hypermethylation is frequently observed in cancer. The potential for this to contribute to tumour development depends on whether the genes affected are repressed because of their methylation. Many aberrantly methylated genes play important roles in development and are bivalently marked in ES cells suggesting that their aberrant methylation may reflect developmental processes. We investigated this possibility by analysing promoter methylation in 19 breast cancer cell lines, 10 normal tissues and 47 primary breast tumours. In order to determine the role of DNA methylation in silencing genes in breast cancer, we also examined the effects of the demethylating agent 5-aza-2?-deoxycytidine on gene expression in 3 breast cancer cell lines and HCT116 cells. Gene expression changes were also assayed in the DNA methyltransferase deficient HCT116 DKO cell line. Our findings implicate aberrant DNA methylation as a marker of cell lineage rather than tumour progression and suggest that, in most cases, it does not cause the repression with which it is associated.
Project description:Blood and endothelial cells arise from hemangiogenic progenitors that are specified from FLK1-expressing mesoderm by the transcription factor ETV2. FLK1 mesoderm also contributes to other tissues, including vascular smooth muscle (VSM) and cardiomyocytes. However, the developmental process of FLK1 mesoderm generation and its derivatives and the lineage relationship among FLK1 mesoderm derivatives these tissues remain obscure. Recent single cell RNA-sequencing (scRNA-seq) studies of early stages of embryogenesis embryos, or in vitro differentiated human embryonic stem (ES) cells have differentiation provided unprecedented information on the spatiotemporal resolution of cells in embryogenesis. Nonetheless, these snapshots still nonetheless offer insufficient information on dynamic developmental processes due to inadvertently missing intermediate states and unavoidable batch effects. Here we performed scRNA-seq of mouse ES cells in asynchronous embryoid bodies (EBs), in vitro differentiated embryonic stem (ES) cells containing undifferentiated ES cells and its differentiated hemangiogenic progeny, as well as yolk sacs, the first hematopoietic extraembryonic tissue in developing embryo that contains hemangiogenic and VSM lineages. We captured a continuous developmental process from undifferentiated pluripotent cells to FLK1 mesoderm-derived tissues involved in hemangiogenesis. This continuous transcriptome map will benefit both basic and applied studies of mesoderm and its derivatives.