Gene Amplification of Mediator Subunit 30 Redirects the MYC Transcriptional Program and Oncogenesis [Pro-Seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE264374 | GEO | 2024/05/30
REPOSITORIES: GEO
Similar Datasets
Project description:Understanding the molecular mechanisms underlying tumorigenesis is crucial for developing effective cancer therapies. Here, we investigate the common co-amplification of MED30 and MYC across diverse cancer types and its impact on oncogenic transcriptional programs. Transcriptional profiling of MYC and MED30 single or both overexpression/amplification revealed the over amount of MED30 lead MYC to a new transcriptional program that associate with poor prognosis. Mechanistically, MED30 overexpression/amplification recruits other Mediator components and binding of MYC to a small subset of novel genomic regulatory sites, changing the epigenetic marks and inducing the formation of new enhancers, which drive the expression of target genes crucial for cancer progression. In vivo studies in pancreatic ductal adenocarcinoma (PDAC) further validate the oncogenic potential of MED30, as its overexpression promotes tumor growth and can be attenuated by knockdown of MYC. Using another cancer type, MED30 knockdown reduces tumor growth particularly in MYC high-expressed glioblastoma (GBM) cell lines. Overall, our study elucidates the critical role of MED30 overexprssion in orchestrating oncogenic transcriptional programs and highlights its potential as a therapeutic target for MYC-amplified cancer.
2024-05-30 | GSE264275 | GEO
Project description:The transcription factor MYC is overexpressed in most cancers, where it drives multiple hallmarks of cancer progression. MYC is known to promote oncogenic transcription by binding to active promoters. In addition, MYC has also been shown to invade distal enhancers when expressed at oncogenic levels, but this enhancer binding has been proposed to have low gene-regulatory potential. Here, we demonstrate that MYC enhancer binding directly promotes cancer type-specific gene programs predictive of poor patient prognosis. MYC induces transcription of enhancer RNA through recruitment of RNAPII, rather than regulating RNAPII pause-release as is the case at promoters. This is mediated by MYC-induced H3K9 demethylation by KDM3A and acetylation by GCN5, leading to enhancer-specific BRD4 recruitment through its bromodomains, which facilitates RNAPII recruitment. Thus, we propose that MYC drives prognostic cancer type-specific gene programs by promoting RNAPII recruitment to enhancers through induction of an epigenetic switch.
2023-11-30 | PXD039586 | Pride
Project description:Introduction: Amplification at chromosome 8q24 is one of the most frequent genomic abnormalities in human cancers and is associated with reduced survival duration in breast and ovarian cancers. The minimal amplified region encodes c-MYC and the non-coding RNA, PVT1 including miR-1204 encoded in exon 1b. Here we analyzed the genomic changes at chromosome 8q24.21 in breast cancer and the functional roles of miR-1204 in breast and ovarian cancer progression. Methods: The genomic changes at chromosome 8q24.21 were detected in 997 breast cancer tumors and 40 breast cancer cell lines. Expression of miR-1204 in breast and ovarian cancer cell lines was investigated by qRT-PCR method. The role of miR-1204 in the tumorigenesis of breast and ovarian cancer was explored using both knockdown and overexpression of miR-1204 in vitro. Candidate miR-1204 target genes from two independent expression microarray datasets and computational predict programs were identified and further validated by qRT-PCR and western blot methods. The role of inhibition of miR-1204 on tamoxifen sensitivity in breast cancer cells was also investigated. Results: MiR-1204 is frequently co-amplified with MYC and expression of miR-1204 is strongly correlated with the expression and amplification of the noncoding PVT1 transcript and less so with MYC in human breast and ovarian cancer cells. Inhibition of miR-1204 decreases cell proliferation and increased apoptosis in breast and ovarian cancer cell lines with 8q24 amplification, but not in lines without amplification and so may be involved in Myc-induced apoptosis. Additionally, overexpression of miR-1204 enhances both breast and ovarian cancer cell growth and Myc-initiated Rat1A cell transformation. Computational and experimental analyses 30 promising candidate miR-1204 target genes. mRNA levels for these genes were assessed after over expression and knockdown of miR-1204 as were protein levels for 10 genes for which antibodies were available. These studies implicated VDR and ESR1 as miR-1204 targets. Inhibition of miR-1204 increased response to tamoxifen in Estrogen Receptor negative breast cancer cell lines. Conclusions: We conclude that amplification of miR-1204 contributes to breast and ovarian pathophysiology at least in part, by increasing proliferation and down regulating apoptosis and by decreasing expression of VDR and ESR1. Seven cell line sample pairs, where samples are LNA transfected with antimiR-1204 or antimiR-1204 control
2012-04-30 | E-GEOD-37185 | biostudies-arrayexpress
Project description:Introduction: Amplification at chromosome 8q24 is one of the most frequent genomic abnormalities in human cancers and is associated with reduced survival duration in breast and ovarian cancers. The minimal amplified region encodes c-MYC and the non-coding RNA, PVT1 including miR-1204 encoded in exon 1b. Here we analyzed the genomic changes at chromosome 8q24.21 in breast cancer and the functional roles of miR-1204 in breast and ovarian cancer progression. Methods: The genomic changes at chromosome 8q24.21 were detected in 997 breast cancer tumors and 40 breast cancer cell lines. Expression of miR-1204 in breast and ovarian cancer cell lines was investigated by qRT-PCR method. The role of miR-1204 in the tumorigenesis of breast and ovarian cancer was explored using both knockdown and overexpression of miR-1204 in vitro. Candidate miR-1204 target genes from two independent expression microarray datasets and computational predict programs were identified and further validated by qRT-PCR and western blot methods. The role of inhibition of miR-1204 on tamoxifen sensitivity in breast cancer cells was also investigated. Results: MiR-1204 is frequently co-amplified with MYC and expression of miR-1204 is strongly correlated with the expression and amplification of the noncoding PVT1 transcript and less so with MYC in human breast and ovarian cancer cells. Inhibition of miR-1204 decreases cell proliferation and increased apoptosis in breast and ovarian cancer cell lines with 8q24 amplification, but not in lines without amplification and so may be involved in Myc-induced apoptosis. Additionally, overexpression of miR-1204 enhances both breast and ovarian cancer cell growth and Myc-initiated Rat1A cell transformation. Computational and experimental analyses 30 promising candidate miR-1204 target genes. mRNA levels for these genes were assessed after over expression and knockdown of miR-1204 as were protein levels for 10 genes for which antibodies were available. These studies implicated VDR and ESR1 as miR-1204 targets. Inhibition of miR-1204 increased response to tamoxifen in Estrogen Receptor negative breast cancer cell lines. Conclusions: We conclude that amplification of miR-1204 contributes to breast and ovarian pathophysiology at least in part, by increasing proliferation and down regulating apoptosis and by decreasing expression of VDR and ESR1.
2012-05-01 | GSE37185 | GEO
Project description:In neuroblastoma, amplification of the oncogenic basic helix-loop-helix (bHLH) transcription factor (TF) MYCN is the defining prognosticator of high-risk disease, occurs in one-third of neuroblastoma, and drastically reduces overall survival rates1,2. As a proto-oncogene, targeted MYCN overexpression in peripheral neural crest is sufficient to initiate disease in mouse models3. In MYCN amplified neuroblastoma, elevated expression of the factor is crucial to maintain tumor stemness4,5 and is associated with increased proliferation and aberrant cell cycle progression, as these tumors lack the ability to arrest in G1 in response to irradiation6-9. MYCN down-regulation broadly reverses these oncogenic phenotypes in a variety of neuroblastoma models10-12 and recent thereapeutic strategies to indirectly target MYCN production or protein stability have reduced tumor growth in vivo13-15. These observations motivate an investigation of MYCN binding in MYCN amplified tumors as it remains fundamentally unclear how elevated levels of the factor occupy the genome and alter transcriptional programs in neuroblastoma. Here we present the first dynamic chromatin and transcriptional landscape of direct MYCN perturbation in neuroblastoma. We find that at oncogenic levels, MYCN associates with E-box (CANNTG) binding motifs in an affinity dependent manner across most active cis-regulatory promoters and enhancers. MYCN shutdown globally reduces histone acetylation and transcription, consistent with prior descriptions of MYC proteins as non-linear amplifiers of gene expression. We establish that MYCN load at the promoter and proximal enhancers predicts transcriptional responsiveness to MYCN shutdown and that MYCN enhancer binding occurs prominently at the most strongly occupied and down-regulated genes, suggesting a role for these tissue specific elements in predicating MYCN responsive â??targetâ?? genes. At these invaded enhancers, we identify the lineage specific bHLH TWIST1 as a key collaborator and dependency of oncogenic MYCN. These data suggest that MYCN enhancer invasion helps shape transcriptional amplification of the neuroblastoma gene expression program to promote tumorigenesis. ATAC-Seq in SHEP21, BE2C, KELLY, NGP, and MM1S cell lines
2016-09-01 | E-GEOD-80152 | biostudies-arrayexpress
Project description:In neuroblastoma, amplification of the oncogenic basic helix-loop-helix (bHLH) transcription factor (TF) MYCN is the defining prognosticator of high-risk disease, occurs in one-third of neuroblastoma, and drastically reduces overall survival rates. As a proto-oncogene, targeted MYCN overexpression in peripheral neural crest is sufficient to initiate disease in mouse models. In MYCN amplified neuroblastoma, elevated expression of the factor is crucial to maintain tumor stemness and is associated with increased proliferation and aberrant cell cycle progression, as these tumors lack the ability to arrest in G1 in response to irradiation. MYCN down-regulation broadly reverses these oncogenic phenotypes in a variety of neuroblastoma models and recent thereapeutic strategies to indirectly target MYCN production or protein stability have reduced tumor growth in vivo. These observations motivate an investigation of MYCN binding in MYCN amplified tumors as it remains fundamentally unclear how elevated levels of the factor occupy the genome and alter transcriptional programs in neuroblastoma. Here we present the first dynamic chromatin and transcriptional landscape of direct MYCN perturbation in neuroblastoma. We find that at oncogenic levels, MYCN associates with E-box (CANNTG) binding motifs in an affinity dependent manner across most active cis-regulatory promoters and enhancers. MYCN shutdown globally reduces histone acetylation and transcription, consistent with prior descriptions of MYC proteins as non-linear amplifiers of gene expression. We establish that MYCN load at the promoter and proximal enhancers predicts transcriptional responsiveness to MYCN shutdown and that MYCN enhancer binding occurs prominently at the most strongly occupied and down-regulated genes, suggesting a role for these tissue specific elements in predicating MYCN responsive âtargetâ genes. At these invaded enhancers, we identify the lineage specific bHLH TWIST1 as a key collaborator and dependency of oncogenic MYCN. These data suggest that MYCN enhancer invasion helps shape transcriptional amplification of the neuroblastoma gene expression program to promote tumorigenesis. ChIP-Seq in SHEP21, BE2C, KELLY, and NGP neuroblastoma cell lines for H3K27ac, H3K4me3, RNA PolII, MYCN, BRD4, or TWIST1
2016-09-01 | E-GEOD-80151 | biostudies-arrayexpress
Project description:The MYC oncogene encodes for the MYC protein and is frequently dysregulated across multiple cancer cell types, making it an attractive target for cancer therapy. MYC overexpression leads to MYC binding at active enhancers, resulting in a global transcriptional amplification of active genes. Since superenhancers are frequently dysregulated in cancer, we hypothesized that MYC preferentially invades into superenhancers and alters the cancer genome organization. To that end, we performed ChIP-seq, RNA-seq, 4C-seq and SIQHiC (Spike-in Quantitative Hi-C) on the U2OS osteosarcoma cell line with tetracycline-inducible MYC. MYC overexpression in U2OS cells modulated histone acetylation and increased MYC binding at superenhancers. SIQHiC analysis revealed increased global chromatin contact frequency, particularly at chromatin interactions connecting MYC binding sites at promoters and enhancers. Immunofluorescence staining showed that MYC molecules formed punctate foci at these transcriptionally active domains after MYC overexpression. These results demonstrate the accumulation of overexpressed MYC at promoter-enhancer hubs and suggest that MYC invades into enhancers through spatial proximity. At the same time, the increased protein-protein interactions may strengthen these chromatin interactions to increase chromatin contact frequency. CTCF siRNA knockdown in MYC overexpressed U2OS cells demonstrated that removal of architectural proteins can disperse MYC and abrogate the increase in chromatin contacts. By elucidating the chromatin landscape of MYC driven cancers, we can potentially target MYC associated chromatin interactions for cancer therapy.
2022-01-17 | GSE164777 | GEO
Project description:The oncogenic transcription factor (c-)Myc is overexpressed in a variety of cancers including subtypes of B cell lymphoma. Here we study long noncoding (lnc)RNAs regulated by Myc, arguing that these lncRNAs may be involved in the very strong effect of Myc on cell proliferation. Using multiple in vitro models and taking into account the kinetics of the response to Myc as well as Myc binding sites we defined two Myc-induced and four Myc-repressed lncRNA candidates. Expression levels of the top Myc-induced lncRNA KTN1-AS1 are low in normal B cell subsets and strongly increased in multiple Myc-positive lymphoma cell lines. In addition, primary lymphoma cases stratified by high or low Myc expression show the expected KTN1-AS1 expression differences. Knockdown of KTN1-AS1 severely impaired the cell growth of multiple Burkitt lymphoma cell lines. Gene expression analysis showed that KTN1-AS1 knockdown affects >300 genes genome wide with a strong enrichment of Myc-target genes involved in metabolism and biosynthesis. In line with this finding, KTN1-AS1 depletion in B cell lymphoma cells caused a substantial decrease of Myc transcript and protein. Thus, our data indicates that KTN1-AS1 overexpression in lymphoma may reinforce high Myc expression at the transcriptional level to activate gene expression programs supporting the high metabolic rate present in lymphoma cells. In conclusion, we identified a novel positive feedback loop between c-Myc and KTN1-AS1 in B cell lymphoma cells. LncRNAs such as KTN1-AS1, that regulate important oncogenic factors in specific cell types, may open new ways to cancer therapy.
2020-04-03 | GSE119923 | GEO
Project description:The oncogenic transcription factor (c-)Myc is overexpressed in a variety of cancers including subtypes of B cell lymphoma. Here we study long noncoding (lnc)RNAs regulated by Myc, arguing that these lncRNAs may be involved in the very strong effect of Myc on cell proliferation. Using multiple in vitro models and taking into account the kinetics of the response to Myc as well as Myc binding sites we defined two Myc-induced and four Myc-repressed lncRNA candidates. Expression levels of the top Myc-induced lncRNA KTN1-AS1 are low in normal B cell subsets and strongly increased in multiple Myc-positive lymphoma cell lines. In addition, primary lymphoma cases stratified by high or low Myc expression show the expected KTN1-AS1 expression differences. Knockdown of KTN1-AS1 severely impaired the cell growth of multiple Burkitt lymphoma cell lines. Gene expression analysis showed that KTN1-AS1 knockdown affects >300 genes genome wide with a strong enrichment of Myc-target genes involved in metabolism and biosynthesis. In line with this finding, KTN1-AS1 depletion in B cell lymphoma cells caused a substantial decrease of Myc transcript and protein. Thus, our data indicates that KTN1-AS1 overexpression in lymphoma may reinforce high Myc expression at the transcriptional level to activate gene expression programs supporting the high metabolic rate present in lymphoma cells. In conclusion, we identified a novel positive feedback loop between c-Myc and KTN1-AS1 in B cell lymphoma cells. LncRNAs such as KTN1-AS1, that regulate important oncogenic factors in specific cell types, may open new ways to cancer therapy.
2020-04-03 | GSE119924 | GEO
Project description:The high frequency of somatic copy number alterations, as opposed to point mutations, is considered a unique feature of high-grade serous ovarian carcinoma (HGSOC). Amplification-dependent overexpression of RECQL4, which participates in DNA replication and repair, mediates the development of various cancers, but its pathobiological and clinical roles are poorly understood. Here, using bioinformatics analysis, RECQL4 amplification was found to occur in 27% of HGSOC samples in the TCGA cohort. RECQL4 was found to be upregulated and associated with a poor prognosis based on the immunohistochemistry staining of HGSOC. Functionally, RECQL4 overexpression increased proliferation and invasion of ovarian cancer cells both in vitro and in vivo. RECQL4 silencing had the opposite effects. In addition, RECQL4 knockdown enhanced the sensitivity of ovarian cancer cells to cisplatin and PARP inhibitor (PARPi). Further mechanistic investigations revealed that MAFB was a downstream target of RECQL4. The oncogenic effect of RECQL4 was attenuated after MAFB knockdown. Moreover, RECQL4 overexpression was negatively regulated by the tumour suppressor miR-10a-5p. Collectively, these findings indicate that genomic amplification and low expression of miR-10a-5p contribute to RECQL4 overexpression in ovarian cancer. This is the first study to reveal the oncogenic functions and clinical significance of RECQL4 in ovarian cancer.
2020-10-13 | GSE153839 | GEO