This SuperSeries is composed of the SubSeries listed below.
EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors in transgenic mice.
Specimen part, Cell line
View SamplesThe newly identified claudin-low subtype of cancer is believed to represent the most primitive breast malignancies, having arisen from transformation of an early epithelial precursor with inherent stemness properties and metaplastic features. Challenging this hypothesis, we show both in vitro and in vivo that transcription factors inducing epithelial-mesenchymal transition can drive the development of claudin-low tumors from differentiated mammary epithelial cells, by playing a dual role in cell transformation and dedifferentiation.
EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors in transgenic mice.
Specimen part, Cell line
View SamplesThe newly identified claudin-low subtype of cancer is believed to represent the most primitive breast malignancies, having arisen from transformation of an early epithelial precursor with inherent stemness properties and metaplastic features. Challenging this hypothesis, we show both in vitro and in vivo that transcription factors inducing epithelial-mesenchymal transition can drive the development of claudin-low tumors from differentiated mammary epithelial cells, by playing a dual role in cell transformation and dedifferentiation.
EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors in transgenic mice.
Specimen part, Cell line
View SamplesDNA methylation is thought to induce a transcriptional silencing through the combination of two mechanisms: the repulsion of transcriptional activators that do not recognize their binding sites when methylated, and the recruitment of transcriptional repressors that specifically bind methylated DNA. Methyl CpG Binding Domain proteins MeCP2, MBD1 and MBD2 belong to the latter category. However, the exact contribution of each protein in the DNA methylation dependent transcriptional repression occurring during development and diseases remains elusive. Here we present MBD2 ChIPseq data generated from the endogenous protein in an isogenic cellular model of human mammary oncogenic transformation. In immortalized or transformed cells, MBD2 was found in one fourth of methylated regions and associated with transcriptional silencing. Depletion of MBD2 induces upregulations of genes bound by MBD2 and methylated in their transcriptional start site regions. MBD2 was partially redistributed on methylated DNA during oncogenic transformation, independently of DNA methylation changes. Genes downregulated during this transformation preferentially gained MBD2 binding sites on their promoter. Depletion of MBD2 in transformed cells induced the upregulation of some of these repressed genes, independently of the strategy used for the abrogation of oncosuppressive barriers. Our data confirm that MBD2 is a major interpret of DNA methylation, and show an unreported dynamic in this interpretation during oncogenic transformation. Overall design: RNAseq of untreated HMEC-hTERT cells, siCtrl, siMBD2 or DAC treated HMLER cells, siCtrl or siMBD2 treated HME-ZEB1-RAS and HME-shP53-RAS cells, in duplicates.
Dynamics of MBD2 deposition across methylated DNA regions during malignant transformation of human mammary epithelial cells.
No sample metadata fields
View SamplesWe have demonstrated that the oncogenic activation of B-RAF (using a truncated delta-BRAF-ER version inducible with tamoxifen) in the melan-a melanocyte cell line triggers the activation of Zeb1 and Twist1 at the expanse of Zeb2 and Snail2. Enforced maintenance of Zeb2 or Snail2 expression reduces the B-RAF oncogenic potential while ectopic expression of Zeb1 or Twist1 cooperates with B-RAF in melan-a cell transformation. To get an insight into the properties of these embryonic transcription factors, gene expression profiles of melan-a-derived cell lines either expressing a non-activated B-RAF (- tamoxifen) or an activated BRAF (+ tamoxifen) alone or in combination with Snail2, Zeb2, Twist1 or Zeb1 have been established.
A switch in the expression of embryonic EMT-inducers drives the development of malignant melanoma.
Cell line
View SamplesThe expression profiles of 64 neuroblastic tumors (mainly neuroblastoma) were determined on Affymetrix chips HG U133 Plus 2.0.
Somatic and germline activating mutations of the ALK kinase receptor in neuroblastoma.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A stemness-related ZEB1-MSRB3 axis governs cellular pliancy and breast cancer genome stability.
Specimen part, Cell line
View SamplesAberrant cell proliferation, a hallmark of most cancers, requires the escape from intrinsic antitumour barriers. Primary among these is the DNA damage response (DDR). In both cell culture-models and in early stages of tumorigenesis in vivo, activated oncogenes induce DNA replication stress and DNA double-strand breaks (DSBs), leading to DDR activation and p53-dependent apoptosis and/or senescence. The means by which tumour-initiating cells, also termed cancer stem cells (CSCs), circumvent this oncosuppressive response is unknown. Here we demonstrate that the ZEB1 transcription factor provides breast CSCs with the ability to withstand an aberrant mitogenic activity. Its forced expression in human mammary epithelial cells is sufficient to alleviate DNA replicative stress and to decrease the production of reactive oxygen species, an important contributor to DDR and oncogene-induced senescence. Consistently, human breast cancer cells with endogenous ZEB1 expression show two characteristic features: low levels of DSBs and DDR markers, reflecting mitigation of the DNA replication stress, and a low p53 mutation frequency, reflecting a weak selective pressure for inactivation. Using high-throughput sequencing analysis of controlled cellular models, we further demonstrate that ZEB1 delays the onset of structural chromosomal instability (CIN), a known consequence of replicative stress and prevents the emergence of chromosome 8p deletions and 8q amplifications, two prevalent abnormalities in high-grade breast cancers. Supporting these findings, ZEB1 expression discriminates human breast tumours by their copy number alterations (CNAs) and chromosome 8 aberrations. We propose that the tumorigenic potential of CSCs relies upon their unique capacity to tolerate oncogenic stimuli through the alleviation of DNA replication stress.
A stemness-related ZEB1-MSRB3 axis governs cellular pliancy and breast cancer genome stability.
Specimen part
View SamplesCooperative dependencies between mutant oncoproteins and wild-type proteins are critical in cancer pathogenesis and therapy resistance. Although spleen tyrosine kinase (SYK) has been implicated in hematologic malignancies, it is rarely mutated. We used kinase activity profiling to identify collaborators of SYK in acute myeloid leukemia (AML) and determined that FMS-like tyrosine kinase 3 (FLT3) is transactivated by SYK via direct binding. Highly activated SYK is predominantly found in FLT3-ITD positive AML and cooperates with FLT3-ITD to activate MYC transcriptional programs. FLT3-ITD AML cells are more vulnerable to SYK suppression than FLT3 wild-type counterparts. In a FLT3-ITD in vivo model, SYK is indispensable for myeloproliferative disease (MPD) development, and SYK overexpression promotes overt transformation to AML and resistance to FLT3-ITD-targeted therapy.
SYK is a critical regulator of FLT3 in acute myeloid leukemia.
Cell line, Treatment
View SamplesExpression of the yeast Cth2 protein stimulates degradation of mRNAs encoding proteins with Fe-dependent functions in metabolism, in iron storage and in other cellular processes. We demonstrate that in response to Fe deprivation, the Cth2-homologue, Cth1, stimulates specific degradation of mRNAs involved in mitochondrially localized activities that include respiration and amino acid biosynthesis. Furthermore, yeast cells grown under Fe deprivation accumulate mRNAs encoding proteins that function in glucose metabolism. These studies demonstrate a reprogramming of cellular metabolism during Fe-starvation dependent on the coordinated activities of two mRNA binding proteins.
Cooperation of two mRNA-binding proteins drives metabolic adaptation to iron deficiency.
No sample metadata fields
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