E2F6-mediated ceRNA and epigenetic silencing of miR-193a promote cancer stemness and immunoevasion in ovarian cancer
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE109184 | GEO | 2019/06/04
REPOSITORIES: GEO
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Project description:E2F6-mediated ceRNA and epigenetic silencing of miR-193a promote cancer stemness and immunoevasion in ovarian cancer
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Project description:In mouse development, long-term silencing by CpG island DNA methylation is specifically targeted to germline genes, however the molecular mechanisms of this specificity remain unclear. Here we demonstrate that the transcription factor E2F6, a member of the polycomb repressive complex 1.6 (PRC1.6), is critical to target and initiate epigenetic silencing at germline genes in early embryogenesis. Genome-wide, E2F6 binds preferentially to CpG islands in embryonic cells. E2F6 cooperates with MGA to silence a subgroup of germline genes in mouse embryonic stem cells and in vivo, a function that critically depends on the E2F6 marked box domain. Inactivation of E2f6 leads to a failure to deposit CpG island DNA methylation at these genes during implantation. Furthermore, E2F6 is required to initiate epigenetic silencing in early embryonic cells but becomes dispensable for the maintenance in differentiated cells. Our findings elucidate the mechanisms of epigenetic targeting of germline genes and provide a paradigm for how transient repression signals by DNA-binding factors in early embryonic cells are translated into long term epigenetic silencing during mammalian development.
2021-04-22 | PXD023974 | Pride
Project description:E2F6 plays oncogenic roles and in order to identify the molecular mechanism of E2F6 to promote tumorigenesis, RNA-seq was performed on Huh7 cells with or without E2F6.
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Project description:RNA-seq data for E2F6 knockdown in Huh7 cells
| PRJNA719120 | ENA
Project description:In the mouse, long-term silencing by CpG island DNA methylation is specifically targeted to germline genes in somatic cells, however the molecular mechanisms of this specificity remain unclear. Here we demonstrate that the transcription factor E2F6, a member of the polycomb repressive complex 1.6 (PRC1.6), is critical to target and initiate epigenetic silencing at germline genes in early embryogenesis. Genome-wide, E2F6 binds preferentially to CpG islands in embryonic cells. E2F6 cooperates with MGA to silence a subgroup of germline genes in mouse embryonic stem cells and in vivo, a function that critically depends on the E2F6 marked box domain. Furthermore, inactivation of E2f6 leads to a failure to deposit CpG island DNA methylation at these genes during implantation. Finally, we show that E2F6 is required to initiate epigenetic silencing in early embryonic cells but becomes dispensable for the maintenance in differentiated cells. Our findings elucidate the mechanisms of epigenetic targeting of germline genes and provide a paradigm for how transient repression signals by DNA-binding factors in early embryonic cells are translated into long term epigenetic silencing during mammalian development.
2021-04-26 | GSE149025 | GEO
Project description:We conducted a genome-wide screen by clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 library to identify genes which are particularly resistant to EGFRvIII GBM cells under the chemo-stress of TMZ. In vitro and in vivo validation of EGFRvIII-specific targets revealed several strong hits, including E2F6. Mechanistic studies demonstrated that E2F6 reveals its resistance to TMZ through NF-κB and TMZ inducement.
2020-06-04 | GSE112733 | GEO
Project description:Ovarian cancer is the most lethal cancer of the female reproductive system. In that regard, several epidemiological studies suggest that long-term exposure to estrogen could increase ovarian cancer risk, although its precise role remains controversial. To decipher a mechanism for this, we previously generated a mathematical model of how estrogen-mediated upregulation of the transcription factor, E2F6, upregulates the ovarian cancer stem/initiating cell marker, c-Kit, by epigenetic silencing the tumor suppressor miR-193a, and a competing endogenous (ceRNA) mechanism. In this study, we tested that previous mathematical model, showing that estrogen treatment of immortalized ovarian surface epithelial cells upregulated both E2F6 and c-KIT, but downregulated miR-193a. Luciferase assays further confirmed that microRNA-193a targets both E2F6 and c-Kit. Interestingly, ChIP-PCR and bisulphite pyrosequencing showed that E2F6 also epigenetically suppresses miR-193a, through recruitment of EZH2, and by a complex ceRNA mechanism in ovarian cancer cell lines. Importantly, cell line and animal experiments both confirmed that E2F6 promotes ovarian cancer stemness, whereas E2F6 or EZH2 depletion derepressed miR-193a, which opposes cancer stemness, by alleviating DNA methylation and repressive chromatin. Finally, 118 ovarian cancer patients with miR-193a promoter hypermethylation had poorer survival than those without hypermethylation. These results suggest that an estrogen-mediated E2F6 ceRNA network epigenetically and competitively inhibits microRNA-193a activity, promoting ovarian cancer stemness and tumorigenesis.
| S-EPMC6398890 | biostudies-other
Project description:We conducted a genome-wide screen by clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 library to identify genes which are particularly resistant to EGFRvIII GBM cells under the chemo-stress of TMZ. In vitro and in vivo validation of EGFRvIII-specific targets revealed several strong hits, including E2F6. Mechanistic studies demonstrated that E2F6 reveals its resistance to TMZ through NF-κB and TMZ inducement.EGFRvIII GBM cells under the chemo-stress of TMZ.
2020-06-04 | GSE112734 | GEO
Project description:In mouse development, long-term silencing by CpG island DNA methylation is specifically targeted to germline genes; however, the molecular mechanisms of this specificity remain unclear. Here, we demonstrate that the transcription factor E2F6, a member of the polycomb repressive complex 1.6 (PRC1.6), is critical to target and initiate epigenetic silencing at germline genes in early embryogenesis. Genome-wide, E2F6 binds preferentially to CpG islands in embryonic cells. E2F6 cooperates with MGA to silence a subgroup of germline genes in mouse embryonic stem cells and in embryos, a function that critically depends on the E2F6 marked box domain. Inactivation of E2f6 leads to a failure to deposit CpG island DNA methylation at these genes during implantation. Furthermore, E2F6 is required to initiate epigenetic silencing in early embryonic cells but becomes dispensable for the maintenance in differentiated cells. Our findings elucidate the mechanisms of epigenetic targeting of germline genes and provide a paradigm for how transient repression signals by DNA-binding factors in early embryonic cells are translated into long-term epigenetic silencing during mouse development.
| S-EPMC8195999 | biostudies-literature
Project description:BackgroundDocetaxel-based chemotherapy failure in advanced prostate carcinoma has partly been attributed to the resistance of prostate cancer (PC) cells to docetaxel-induced apoptosis. Hence, there is an urgent need to identify mechanisms of docetaxel chemoresistance and to develop new combination therapies.MethodsmiR-193a-5p level was evaluated by qPCR in prostate tissues and cell lines, and its expression in the tissues was also examined by in situ hybridization. PC cell line (PC3 cell) was transfected with miR-193a-5p mimic or its inhibitor, and then cell apoptosis and the expression of its downstream genes Bach2 and HO-1 were detected by TUNEL staining and Western blotting. Luciferase reporter assay was used to detect the effect of miR-193a-5p and Bach2 on HO-1 expression. Xenograft animal model was used to test the effect of miR-193a-5p and docetaxel on PC3 xenograft growth.ResultsmiR-193a-5p was upregulated in PC tissues and PC cell lines, with significant suppression of PC3 cell apoptosis induced by oxidative stress. Mechanistically, miR-193a-5p suppressed the expression of Bach2, a repressor of the HO-1 gene, by directly targeting the Bach2 mRNA 3'-UTR. Docetaxel treatment modestly decreased Bach2 expression and increased HO-1 level in PC3 cells, whereas a modest increase of HO-1 facilitated docetaxel-induced apoptosis. Notably, docetaxel-induced miR-193a-5p upregulation, which in turn inhibits Bach2 expression and thus relieves Bach2 repression of HO-1 expression, partly counteracted docetaxel-induced apoptosis, as evidenced by the increased Bcl-2 and decreased Bax expression. Accordingly, silencing of miR-193a-5p enhanced sensitization of PC3 cells to docetaxel-induced apoptosis. Finally, depletion of miR-193a-5p significantly reduced PC xenograft growth in vivo.ConclusionsSilencing of miR-193a-5p or blockade of the miR-193a-5p-Bach2-HO-1 pathway may be a novel therapeutic approach for castration-resistant PC.
| S-EPMC5721613 | biostudies-literature