Translational control of breast cancer plasticity
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE149132 | GEO | 2020/04/27
REPOSITORIES: GEO
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Project description:DEAD-box RNA-binding proteins (RBPs) play a significant role in RNA metabolism to achieve cellular homeostasis, including miRNA biogenesis and transcription. Hypoxia induces stemness cell-like characteristics in cancer cells and promotes malignant progression. Despite the fact that hypoxia can induce the changes in protein and RNA modification, thereby regulating downstream gene expressions, how modifications at different molecular layers interplay with each other are poorly understood. Here we show that hypoxia induces HectH9-mediated K63-linked polyubiquitination of the DEAD-box protein DDX17 as well as reduces N6-methyladenosine (m6A) marks in pri-miRNAs. While m6A potentiates DDX17 binding to pri-miRNAs, decreased m6A modifications of pri-miRNAs and increased polyubiquitination of DDX17 under hypoxia lead to decreased DDX17 binding to pri-miRNAs binding. These events enhance the association of DDX17 with the ubiquitin receptor p300 and lead to a decrease in miRNA biogenesis, especially for miRNAs regulating stemness and stemness-related genes. In addition, polyubiquitinated DDX17 together with p300 upregulates H3K56Ac levels on the stemness and stemness-related genes, resulting in enhancement of tumor initiating ability. Post-transcriptionally, decreased miRNA production, including those targeting stemness genes or stemness-related genes, also facilitates tumor initiation. Together, hypoxia triggers DDX17 poly-ubiquitination, which orchestrates dual mechanisms to increase tumor initiating ability and promote tumor progression.
2018-03-09 | PXD006059 | JPOST Repository
Project description:The dosage-dependent recruitment of RNA polymerase II (Pol II) at the promoters of genes related to neurodevelopment and stem cell maintenance is required for transcription by the fine-tuned expression of SET-domain-containing protein 5 (SETD5). Pol II O-GlcNAcylation by O-GlcNAc transferase (OGT) is critical for preinitiation complex formation and transcription cycling. SETD5 dysregulation has been linked to stem cell-like properties in some cancer types; however, the role of SETD5 in cancer cell stemness has not yet been determined. We here show that aberrant SETD5 overexpression induces stemness in colorectal cancer (CRC) cells. SETD5 overexpression causes the upregulation of PI3K-AKT pathway-related genes and cancer stem cell (CSC) markers such as CD133, Kruppel-like factor 4 (KLF4), and estrogen-related receptor beta (ESRRB), leading to the gain of stem cell-like phenotypes. Our findings also revealed a functional relationship between SETD5, OGT, and Pol II. OGT-catalyzed Pol II glycosylation depends on SETD5, and the SETD5-Pol II interaction weakens in OGT-depleted cells, suggesting a SETD5-OGT-Pol II interdependence. SETD5 deficiency reduces Pol II occupancy at PI3K-AKT pathway-related genes and CD133 promoters, suggesting a role for SETD5-mediated Pol II recruitment in gene regulation. Moreover, the SETD5 depletion nullified the SETD5-induced stemness of CRC cells and Pol II O-GlcNAcylation. These findings support the hypothesis that SETD5 mediates OGT-catalyzed O-GlcNAcylation of RNA Pol II, which is involved in cancer cell stemness gain via CSC marker gene upregulation.
2023-11-16 | PXD041141 | Pride
Project description:MicroRNAs are small regulatory RNAs that post-transcriptionally control gene expression. Reduced expression of DICER, the enzyme involved in microRNA processing, is frequently observed in cancer and is associated with poor clinical outcome in various malignancies. Yet the underlying mechanisms are not well understood. Here, we identify tumor hypoxia as a regulator of DICER expression in large cohorts of breast cancer patients. We show that DICER expression is suppressed by hypoxia through an epigenetic mechanism that involves inhibition of oxygen-dependent H3K27me3 demethylases KDM6A/B and results in silencing of the DICER promoter. Subsequently, reduced miRNA processing leads to derepression of the miR-200 target ZEB1, stimulates the epithelial to mesenchymal transition and ultimately results in the acquisition of stem cell phenotypes in human mammary epithelial cells. Our study uncovers a previously unknown relationship between oxygen-sensitive epigenetic regulators, miRNA biogenesis and tumor stem cell phenotypes that may underlie poor outcome in breast cancer. miRNA profiling of MCF7 cells in normal or hypoxic conditions or after DICER knockdown in MCF7 cells.
2014-09-30 | E-GEOD-61720 | biostudies-arrayexpress
Project description:MicroRNAs are small regulatory RNAs that post-transcriptionally control gene expression. Reduced expression of DICER, the enzyme involved in microRNA processing, is frequently observed in cancer and is associated with poor clinical outcome in various malignancies. Yet the underlying mechanisms are not well understood. Here, we identify tumor hypoxia as a regulator of DICER expression in large cohorts of breast cancer patients. We show that DICER expression is suppressed by hypoxia through an epigenetic mechanism that involves inhibition of oxygen-dependent H3K27me3 demethylases KDM6A/B and results in silencing of the DICER promoter. Subsequently, reduced miRNA processing leads to derepression of the miR-200 target ZEB1, stimulates the epithelial to mesenchymal transition and ultimately results in the acquisition of stem cell phenotypes in human mammary epithelial cells. Our study uncovers a previously unknown relationship between oxygen-sensitive epigenetic regulators, miRNA biogenesis and tumor stem cell phenotypes that may underlie poor outcome in breast cancer. A total of 12 samples were analyzed. For each condition tested, 3 independent experiments were carried out (biological repicates).
2014-09-30 | E-GEOD-61721 | biostudies-arrayexpress
Project description:To understand the role of the epithelial-to-mesenchymal transition (EMT) and its reverse MET dynamics between health and disease, the identification of epithelial (E)- and mesenchymal (M)-specific genes is essential. The aim of the study was to derive genes that are characteristic E and M phenotypes in breast-derived cells. Their identification can help to understand the functional meaning of their expression and dynamic changes of individual cells, whole cell populations, and tumors, and even patients. Breast cancer stem cells (CSCs) are thought to drive recurrence and metastasis. Their identity has been linked to the epithelial-to-mesenchymal transition (EMT) but remains highly controversial since -- depending on the cell line studied -- either epithelial (E) or mesenchymal (M) markers, alone or together, have been associated with stemness. Using distinct transcript expression signatures characterizing the three different E, M and hybrid E/M cell types, our data support a novel model that links a mixed E/M signature with stemness in 1) individual cells, 2) luminal and basal cell lines, 3) in vivo xenograft mouse models, and 4) in all breast cancer subtypes. In particular, we found that co-expression of E and M signatures was associated with poorest outcome in luminal and basal breast cancer patients, as well as with enrichment for stem-like cells in both E and M breast cell lines. This link between a mixed E/M expression signature and stemness was explained by two findings: first, mixed cultures of E and M cells showed increased cooperation in mammosphere formation (indicative of stemness). Second, single-cell qPCR analysis revealed that E and M genes could be co-expressed in the same cell. These hybrid E/M cells were generated by both E or M cells and had stem-like character since they displayed increased plasticity, produced ALDH1+ progenies self-renewal and mammosphere formation compared to the more differentiated E and M cell types. Thus, the hybrid E/M state reflecting stemness and its promotion by E-M cooperation offers a dual biological rationale for the robust association of the mixed E/M signature with poor prognosis, independent of cellular origin. Together, our model explains previous paradoxical findings that breast CSCs appear to be M in luminal cell lines but E in basal breast cancer cell lines. Our results suggest that targeting E/M heterogeneity by eliminating hybrid E/M cells and cooperation between E and M cell types could improve breast cancer patient survival independent of breast cancer-subtype.
2015-03-17 | GSE66527 | GEO
Project description:Epithelial cells possess remarkable plasticity, having the ability to become mesenchymal cells through alterations in adhesion and motility (epithelial-to-mesenchymal transition or EMT). Recent studies suggest that EMT endows differentiated epithelial cells with stem cell traits, posing the interesting question of how epithelial plasticity is properly restricted to ensure epithelial differentiation during tissue morphogenesis. Here we identify zinc-finger transcription factor Ovol2 as a key suppressor of EMT of mammary epithelial cells. Epithelia-specific deletion of Ovol2 completely arrests mammary ductal morphogenesis, and depletes epithelial stem/progenitor cell reservoirs. Further, Ovol2-deficient epithelial cells undergo EMT in vivo to become non-epithelial cell types, and that Ovol2 directly represses key EMT inducers such as Zeb1 and regulates stem/progenitor cell responsiveness to TGF-beta. We also provide evidence for a suppressive role of Ovol2 in breast cancer progression. Our findings underscore the critical importance of exquisitely regulating epithelial plasticity to balance stemness with epithelial differentiation in development and cancer. We report ChIPseq data illustrating Ovol2 genome-wide targets in mouse mammary epithelial cells, suggesting that Ovol2 regulates a plethora of genes associated with the EMT process. Immunoprecipitated samples from HC11 mouse mammary epithelial cells with antibodies against Ovol2 and control IgG respectively were used for ChIP-seq experiments.
2014-03-19 | E-GEOD-53925 | biostudies-arrayexpress
Project description:Epithelial cells possess remarkable plasticity, having the ability to become mesenchymal cells through alterations in adhesion and motility (epithelial-to-mesenchymal transition or EMT). Recent studies suggest that EMT endows differentiated epithelial cells with stem cell traits, posing the interesting question of how epithelial plasticity is properly restricted to ensure epithelial differentiation during tissue morphogenesis. Here we identify zinc-finger transcription factor Ovol2 as a key suppressor of EMT of mammary epithelial cells. Epithelia-specific deletion of Ovol2 completely arrests mammary ductal morphogenesis, and depletes epithelial stem/progenitor cell reservoirs. Further, Ovol2-deficient epithelial cells undergo EMT in vivo to become non-epithelial cell types, and that Ovol2 directly represses key EMT inducers such as Zeb1 and regulates stem/progenitor cell responsiveness to TGF-beta. We also provide evidence for a suppressive role of Ovol2 in breast cancer progression. Our findings underscore the critical importance of exquisitely regulating epithelial plasticity to balance stemness with epithelial differentiation in development and cancer. TEBs from control and conditional Ovol2-knockout mammary glands were physically isolated for RNA extraction and hybridization on Affymetrix microarrays. In order to identify primary changes, we analyzed TEBs from 24-25-day-old mice, when morphological differences between control and Ovol2 SSKO were still minimal.
2014-03-19 | E-GEOD-53923 | biostudies-arrayexpress
Project description:Epithelial-to-mesenchymal transition (EMT) is a dynamic process that relies on cellular plasticity; an EMT/MET axis is critical for metastatic colonization of carcinomas. Unlike epithelial programming, regulation of mesenchymal programming is not well understood in EMT. Here we describe the first microRNA that enhances exclusively mesenchymal programming. We demonstrate that microRNA-424 is up-regulated early during a TWIST1/SNAI1-induced EMT, and that it causes cells to express mesenchymal genes without affecting epithelial genes, resulting in a mixed/intermediate EMT. Further, microRNA-424 increases motility, decreases adhesion and induces a growth arrest, changes associated with a complete EMT. Patient microRNA-424 levels positively associate with TWIST1/2 and EMT-like gene signatures and is increased in primary tumors versus matched normal breast. However, microRNA-424 is down-regulated in metastases versus matched primary tumors. Correspondingly, microRNA-424 decreases tumor initiation and is post-transcriptionally down-regulated in macrometastases in mice. RNA-seq identified microRNA-424 regulates numerous genes associated with EMT and breast cancer stemness including the novel miR-424 target, TGFBR3, which regulates mesenchymal phenotypes without influencing miR-424 effects on tumor-initiating phenotypes; instead, we show that ERK signaling is critical for such tumor-initiating effects of miR-424. These findings suggest microRNA-424 plays distinct roles downstream of EMT-inducing factors, facilitating earlier stages, but repressing later stages, of metastasis. Examination of mRNA levels in MCF12A human breast cell lines that stably over-expressed miR-424 or an empty vector (EV) control. Each group has three replicates.
2015-02-26 | E-GEOD-54505 | biostudies-arrayexpress
Project description:The receptor tyrosine kinase AXL is associated with epithelial plasticity in several solid tumors including breast cancer and AXL-targeting agents are currently in clinical trials. We hypothesized that AXL is a driver of stemness traits in cancer by co-option of a regulatory function normally reserved for stem cells. AXL-expressing cells in human mammary epithelial ducts co-expressed markers associated with multipotency, and AXL inhibition abolished colony-formation and self-maintenance activities while promoting terminal differentiation in vitro. Axl-null mice did not exhibit a strong developmental phenotype, but enrichment of Axl+ cells was required for mouse mammary gland reconstitution upon transplantation, and Axl-null mice had reduced incidence of Wnt1-driven mammary tumors. An AXL-dependent gene signature is a feature of transcriptomes in basal breast cancers, and reduced patient survival irrespective of subtype. Our interpretation is that AXL regulates access to epithelial plasticity programs in MaSCs and, when coopted, maintains acquired stemness in breast cancer cells.
2020-08-25 | GSE156662 | GEO
Project description:Ovarian cancer (OC) is the most lethal gynecological cancer due to its late diagnosis and, importantly, its high rate of chemoresistance. Hypoxia in solid tumors is an important source of chemoresistance that can determine poor patient prognosis. Such chemoresistance relies on the presence of cancer stem cells (CSCs), and hypoxia promotes their generation through transcriptional activation by HIF transcription factors. We use OC cell lines, xenograft models, OC patient samples, transcriptional databases, iPSCs and ATAC-seq. We show here that hypoxia induces the formation of ovarian CSCs through transcriptional activation of the PLD2 gene encoding phospholipase D2. HIF-1 activates PLD2 transcription through hypoxia response elements located within PLD2 promoter and an intronic enhancer. PLD2 overexpression leads to similar effects than hypoxia, increasing CSC-like features, stemness gene expression and enhancing cell reprogramming in OC cells, as well as chromatin accessibility around stemness genes detected by ATAC-seq. Conversely, PLD2 depletion in hypoxia partially suppresses these effects, indicating that PLD2 is a major determinant of hypoxia-induced CSC generation in OC. Indeed, PLD2 expression is high in OC patients leading to poor survival and a transcriptional switch in the genes related to the response to hypoxia and stemness. Finally, we demonstrate that PLD2 overexpression provokes resistance to platinum-based chemotherapy and that combination of cisplatin with pharmacological inhibition of PLD2 suppresses such resistance. Altogether, our work highlights the importance of the HIF-1-PLD2 axis for CSC generation and chemoresistance in OC and proposes an alternative treatment for patients with high PLD2 expression.
2023-08-06 | GSE210599 | GEO