Project description:Both gains and losses of DNA methylation are common in cancer but the factors controlling this methylation balance remain unclear. Triple negative breast cancer (TNBC), a subtype that does not overexpress hormone receptors or HER2/NEU is one of the most hypomethylated cancers observed. In search for an explanation for this, we discovered that the TET1 DNA demethylase is specifically overexpressed in about 40% of patients with TNBC, where it is associated with hypomethylation of up to 10% of queried CpG sites and a worse overall survival. Through bioinformatic analyses in both breast and ovarian cancer cell line panels, we uncovered an intricate network connecting TET1 to hypomethylation and activation of cancer specific oncogenic pathways including PI3K, EGFR and PDGF. TET1 expression correlated with sensitivity to drugs targeting the PI3K-mTOR pathway. CRISPR mediated deletion of TET1 in two independent TNBC cell lines resulted in reduced expression of PI3K pathway genes, upregulation of immune response genes and substantially reduced cellular proliferation, suggesting dependence of oncogenic pathways on TET1 overexpression. Our work establishes TET1 as a potential oncogene that contributes to aberrant hypomethylation in cancer and suggests that TET1 could serve as a novel druggable target for therapeutic intervention.
Project description:Both gains and losses of DNA methylation are common in cancer but the factors controlling this methylation balance remain unclear. Triple negative breast cancer (TNBC), a subtype that does not overexpress hormone receptors or HER2/NEU is one of the most hypomethylated cancers observed. In search for an explanation for this, we discovered that the TET1 DNA demethylase is specifically overexpressed in about 40% of patients with TNBC, where it is associated with hypomethylation of up to 10% of queried CpG sites and a worse overall survival. Through bioinformatic analyses in both breast and ovarian cancer cell line panels, we uncovered an intricate network connecting TET1 to hypomethylation and activation of cancer specific oncogenic pathways including PI3K, EGFR and PDGF. TET1 expression correlated with sensitivity to drugs targeting the PI3K-mTOR pathway. CRISPR mediated deletion of TET1 in two independent TNBC cell lines resulted in reduced expression of PI3K pathway genes, upregulation of immune response genes and substantially reduced cellular proliferation, suggesting dependence of oncogenic pathways on TET1 overexpression. Our work establishes TET1 as a potential oncogene that contributes to aberrant hypomethylation in cancer and suggests that TET1 could serve as a novel druggable target for therapeutic intervention.
Project description:Dissection of catalytic and non-catalytic functions of Tet1. DNA methylation (RRBS) profiling of wild type, Tet1 knockout and catalytic mutants during EpiLC differentiation.
Project description:EpCAM is frequently overexpressed in human invasive breast cancer. We reported EpCAM overexpression to be an independent prognostic marker for poor overall survival in node-positive breast cancer. We used microarrays in order to investigate changes of the transcriptome on EpCAM gene overexpression in human breast cancer cells Hs578T cells were found to express only very little EpCAM mRNA and protein in comparison to established and well characterized breast cancer cell lines such as MCF-7 or SK-BR-3. Hs578T cells were stably transfected with the EpCAM cDNA containing construct pIRESpuro3_EpCAM and the respective empty vector control.
Project description:This experiment is performed to reveal the novel binding sites of ZEB1 transcription factor globally in triple negative breast cancer cell line Hs578T. We also reveal the effect of TGF cytokine on the binding sites of ZEB1.
Project description:Global gene expression profile of Tet1 knockout ES cells is compared to wild-type ES cells. All ES lines used are V6.5 (mix 129 C57BL6 backgound). 2 Tet1 KO mice compared to 1 Tet1 wild type mouse.
Project description:This experiment is performed to reveal the novel binding sites of Snai1 transcription factor globally in triple negative breast cancer cell line Hs578T. We also reveal the effect of TGF cytokine on the binding sites of Snai1.
Project description:FBP1 is a rate limiting enzyme in glucogenogenesis and FBP1 expression changes cells to oxidative phosphorylation. Expressing FBP1 in basal-like breast cancer cells, which lack the expression of this enzyme, will identify the genes involved in glycolysis. FBP1 was expressed in MDA-MB231 and Hs578T cells, stable clones were selected, and RNA was prepared for microarray analysis.