Dynamic Chromatin Modification Sustains Epithelial-Mesenchymal Transition following Inducible Expression of Snail-1
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE52593 | GEO | 2013/12/18
SECONDARY ACCESSION(S): PRJNA229425
REPOSITORIES: GEO
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Project description:Epithelial-mesenchymal transition (EMT) is thought to contribute to cancer metastasis, but its underlying mechanisms are not well understood. To define early steps in this cellular transformation, we analyzed human mammary epithelial cells with tightly regulated expression of Snail-1, a master regulator of EMT. After Snail-1 induction, epithelial markers were repressed within 6 hr, and mesenchymal genes were induced at 24 hr. Snail-1 binding to its target promoters was transient (6-48 hr) despite continued protein expression, and it was followed by both transient and long-lasting chromatin changes. Pharmacological inhibition of selected histone acetylation and demethylation pathways suppressed the induction as well as the maintenance of Snail-1-mediated EMT. Thus, EMT involves an epigenetic switch that may be prevented or reversed with the use of small-molecule inhibitors of chromatin modifiers.
| S-EPMC4034764 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2013-12-18 | E-GEOD-52593 | biostudies-arrayexpress
Project description:Epithelial-Mesenchymal Transition (EMT) is thought to contribute to cancer metastasis, but its underlying mechanisms are not well understood. To define early steps in this cellular transformation, we analyzed human mammary epithelial cells with tightly regulated expression of Snail-1, a master regulator of EMT. Following Snail-1 induction, epithelial markers were repressed within 6 hours and mesenchymal genes induced at 24 hours. Snail-1 binding to its target promoters was transient (6-48 hours) despite continued protein expression and it was followed by both transient and long-lasting chromatin changes. To generate a potent reversible EMT-inducing stimulus, we created a Snail-1 retroviral expression construct, using a fused estrogen receptor (ER) response element to mediate regulation by exogenous 4-hydroxy-tamoxifen (4-OHT). Since Snail-1 protein stability and nuclear localization are suppressed by GSK3-beta-mediated phosphorylation, we substituted the six targeted amino acids (ER-Snail-1(6SA)), thus conferring constitutive activity to the induced protein (Zhou et al., 2004, Pubmed ID 15448698). Infection of non-transformed, immortalized human mammary epithelial MCF10A cells with ER-Snail-1(6SA), followed by treatment with 4-OHT, triggered morphological and biomarker characteristics of EMT. At 0, 6, 48 and 120 hours after beginning exposure to 4-OHT in ethanol (or, for controls, ethanol only) we ChIPed Snail-1 and 6 histone marks. We perfomed two replicates of each, except we only had one replicate of H3K27Me3 at 6 hours.
2013-12-18 | E-GEOD-52591 | biostudies-arrayexpress
Project description:Epithelial-Mesenchymal Transition (EMT) is thought to contribute to cancer metastasis, but its underlying mechanisms are not well understood. To define early steps in this cellular transformation, we analyzed human mammary epithelial cells with tightly regulated expression of Snail-1, a master regulator of EMT. Following Snail-1 induction, epithelial markers were repressed within 6 hours and mesenchymal genes induced at 24 hours. Snail-1 binding to its target promoters was transient (6-48 hours) despite continued protein expression and it was followed by both transient and long-lasting chromatin changes. To generate a potent reversible EMT-inducing stimulus, we created a Snail-1 retroviral expression construct, using a fused estrogen receptor (ER) response element to mediate regulation by exogenous 4-hydroxy-tamoxifen (4-OHT). Since Snail-1 protein stability and nuclear localization are suppressed by GSK3-beta-mediated phosphorylation, we substituted the six targeted amino acids (ER-Snail-1(6SA)), thus conferring constitutive activity to the induced protein (Zhou et al., 2004, Pubmed ID 15448698). Infection of non-transformed, immortalized human mammary epithelial MCF10A cells with ER-Snail-1(6SA), followed by treatment with 4-OHT, triggered morphological and biomarker characteristics of EMT. At 3, 6, 12, 24, 72 and 120 hours after beginning exposure to 4-OHT in ethanol (or, for controls, ethanol only) we extracted RNA and did gene expression analysis using microarrays. We perfomed three replicates of each.
2013-12-18 | E-GEOD-52592 | biostudies-arrayexpress
Project description:Epithelial-Mesenchymal Transition (EMT) is thought to contribute to cancer metastasis, but its underlying mechanisms are not well understood. To define early steps in this cellular transformation, we analyzed human mammary epithelial cells with tightly regulated expression of Snail-1, a master regulator of EMT. Following Snail-1 induction, epithelial markers were repressed within 6 hours and mesenchymal genes induced at 24 hours. Snail-1 binding to its target promoters was transient (6-48 hours) despite continued protein expression and it was followed by both transient and long-lasting chromatin changes.
2013-12-18 | GSE52592 | GEO
Project description:Epithelial-Mesenchymal Transition (EMT) is thought to contribute to cancer metastasis, but its underlying mechanisms are not well understood. To define early steps in this cellular transformation, we analyzed human mammary epithelial cells with tightly regulated expression of Snail-1, a master regulator of EMT. Following Snail-1 induction, epithelial markers were repressed within 6 hours and mesenchymal genes induced at 24 hours. Snail-1 binding to its target promoters was transient (6-48 hours) despite continued protein expression and it was followed by both transient and long-lasting chromatin changes.
2013-12-18 | GSE52591 | GEO
Project description:Reprogramming of fibroblasts to induced pluripotent stem cells (iPSCs) entails a mesenchymal to epithelial transition (MET). While attempting to dissect the mechanism of MET during reprogramming, we observed that knockdown (KD) of the epithelial-to-mesenchymal transition (EMT) factor SNAI1 (SNAIL) paradoxically reduced, while overexpression enhanced, reprogramming efficiency in human cells and in mouse cells, depending on strain. We observed nuclear localization of SNAI1 at an early stage of fibroblast reprogramming and using mouse fibroblasts expressing a knockin SNAI1-YFP reporter found cells expressing SNAI1 reprogrammed at higher efficiency. We further demonstrated that SNAI1 binds the let-7 promoter, which may play a role in reduced expression of let-7 microRNAs, enforced expression of which, early in the reprogramming process, compromises efficiency. Our data reveal an unexpected role for the EMT factor SNAI1 in reprogramming somatic cells to pluripotency.
| S-EPMC4235745 | biostudies-literature
Project description:Epithelial-to-mesenchymal transition (EMT) and the reverse process (MET) play central role in organ developmental biology. It is a fine tuned process that when disturbed leads to pathological conditions especially cancers with aggressive and metastatic behavior. Snail is an oncogene that has been well established to be a promoter of EMT through direct repression of epithelial morphology promoter E-cadherin. It can function in the nucleus, in the cytosol and as discovered recently, extracellularly through secretory vesicular structures. The intracellular transport of snail has for long been shown to be regulated by the nuclear pore complex. One of the Karyopherins, importin alpha, mediates snail import, while exportin 1 (Xpo1) also known as chromosome maintenance region 1 (CRM1) is its major nuclear exporter. A number of additional biological regulators are emerging that directly modulate Snail stability by altering its subcellular localization. These observations indicate that targeting the nuclear transport machinery could be an important and as of yet, unexplored avenue for therapeutic intervention against the EMT processes in cancer. In parallel, a number of novel agents that disrupt nuclear transport have recently been discovered and are being explored for their anti-cancer effects in the early clinical settings. Through this review we provide insights on the mechanisms regulating snail subcellular localization and how this impacts EMT. We discuss strategies on how the nuclear transport function can be harnessed to rein in EMT through modulation of snail signaling.
| S-EPMC4165636 | biostudies-literature
Project description:BackgroundHypoxia is an element of the tumour microenvironment that impacts upon numerous cellular factors linked to clinical aggressiveness in cancer. One such factor, Snail, a master regulator of the epithelial-mesenchymal transition (EMT), has been implicated in key tumour biological processes such as invasion and metastasis. In this study we set out to investigate regulation of EMT in hypoxia, and the importance of Snail in cell migration and clinical outcome in breast cancer.MethodsFour breast cancer cell lines were exposed to 0.1% oxygen and expression of EMT markers was monitored. The migratory ability was analysed following Snail overexpression and silencing. Snail expression was assessed in 500 tumour samples from premenopausal breast cancer patients, randomised to either 2 years of tamoxifen or no adjuvant treatment.ResultsExposure to 0.1% oxygen resulted in elevated levels of Snail protein, along with changes in vimentin and E-cadherin expression, and in addition increased migration of MDA-MB-468 cells. Overexpression of Snail increased the motility of MCF-7, T-47D and MDA-MB-231 cells, whereas silencing of the protein resulted in decreased migratory propensity of MCF-7, MDA-MB-468 and MDA-MB-231 cells. Moreover, nuclear Snail expression was associated with tumours of higher grade and proliferation rate, but not with disease recurrence. Interestingly, Snail negativity was associated with impaired tamoxifen response (P=0.048).ConclusionsOur results demonstrate that hypoxia induces Snail expression but generally not a migratory phenotype, suggesting that hypoxic cells are only partially pushed towards EMT. Furthermore, our study supports the link between Snail and clinically relevant features and treatment response.
| S-EPMC2778529 | biostudies-literature
Project description:Epithelial cells form spatially-organized adhesion complexes that establish polarity gradients, regulate cell proliferation, and direct wound healing. As cells accumulate oncogenic mutations, these key tumor suppression mechanisms are disrupted, eliminating many adhesion complexes and bypassing contact inhibition. The transcription factor Snail is often expressed in malignant cancers, where it promotes transcriptional reprogramming to drive epithelial-mesenchymal transition (EMT) and establishes a more invasive state. S-Palmitoylation describes the fatty-acyl post-translational modification of cysteine residues in proteins, and is required for membrane anchoring, trafficking, localization and function of hundreds of proteins involved in cell growth, polarity, and signaling. Since Snail-expression disrupts apico-basolateral cell polarity, we asked if Snail-dependent transformation induces proteome-wide changes in S-palmitoylation. MCF10A breast cancer cells were retrovirally transduced with Snail and correlated proteome-wide changes in protein abundance and S-palmitoylation were profiled by using stable isotope labeling in cell culture with amino acid (SILAC) mass spectrometry. This analysis identified increased levels of proteins involved in migration, glycolysis, and cell junction remodeling, and decreased levels of proteins involved in cell adhesion. Overall, protein S-palmitoylation is highly correlated with protein abundance, yet for a subset of proteins, this correlation is uncoupled. These findings suggest that Snail-overexpression affects the S-palmitoylation cycle of some proteins, which may participate in cell polarity and tumor suppression.
| S-EPMC5017304 | biostudies-literature