Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA146337 | ENA |
REPOSITORIES: ENA
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Project description:Cancer cells exhibit the ability to proliferate indefinitely, but paradoxically, overexpression of cellular oncogenes in primary cells can result in a rapid and irreversible cell cycle arrest known as oncogene-induced senescence (OIS). However, we have shown that constitutive overexpression of the oncogene c-MYC in primary human foreskin fibroblasts results in a population of cells with unlimited lifespan; these immortalized cells are henceforth referred to as iMYC. Here, in order to further elucidate the mechanisms underlying the immortalization process, a gene expression signature of three independently established iMYC cell lines compared to matched early passage c-MYC overexpressing cells was derived. Network analysis of this "iMYC signature" indicated that a large fraction of the down-regulated genes were functionally connected and major nodes centered around the TGFb, IL-6 and IGF-1 signaling pathways. Here, we focused on the functional validation of the alteration of TGFb response during c-MYC-mediated immortalization. The results demonstrate loss of sensitivity of iMYC cells to activation of TGFb signaling upon ligand addition. Furthermore, we show that aberrant regulation of the p27 tumor suppressor protein in iMYC cells is a key event that contributes to loss of response to TGFb. These findings highlight the potential to reveal key pathways contributing to the self-renewal of cancer cells through functional mining of the unique gene expression signature of cells immortalized by c-MYC. Cell Cycle. 2011 Aug 1;10(15). Cell culture. Human foreskin fibroblast cell lines expressing empty vector pBABE or vector with gene sequence encoding c-MYC were previously described in PMID 17982115. Cells were cultured in Dulbecco’s modified eagle medium (DMEM) supplemented with 10% fetal bovine serum and penicillinstreptomycin. For cell growth assays, equal number of cells per cell line were plated and counted on the specified days after plating. Microarray analysis. Total RNA was purified using an RNeasy kit (Qiagen, Valencia, CA). Genome-scale expression analysis was performed using custom microarrays (Affymetrix, Santa Clara, CA) containing oligonucleotide probes corresponding to approximately 22,000 human genes. Microarray analysis was performed as described in PMID 12925520. Data were analyzed using Rosetta Resolver(TM) software. We determined a p-value cutoff of 0.01 for genes in all three samples.
2011-08-03 | E-GEOD-31002 | biostudies-arrayexpress
Project description:Cancer cells exhibit the ability to proliferate indefinitely, but paradoxically, overexpression of cellular oncogenes in primary cells can result in a rapid and irreversible cell cycle arrest known as oncogene-induced senescence (OIS). However, we have shown that constitutive overexpression of the oncogene c-MYC in primary human foreskin fibroblasts results in a population of cells with unlimited lifespan; these immortalized cells are henceforth referred to as iMYC. Here, in order to further elucidate the mechanisms underlying the immortalization process, a gene expression signature of three independently established iMYC cell lines compared to matched early passage c-MYC overexpressing cells was derived. Network analysis of this "iMYC signature" indicated that a large fraction of the down-regulated genes were functionally connected and major nodes centered around the TGFb, IL-6 and IGF-1 signaling pathways. Here, we focused on the functional validation of the alteration of TGFb response during c-MYC-mediated immortalization. The results demonstrate loss of sensitivity of iMYC cells to activation of TGFb signaling upon ligand addition. Furthermore, we show that aberrant regulation of the p27 tumor suppressor protein in iMYC cells is a key event that contributes to loss of response to TGFb. These findings highlight the potential to reveal key pathways contributing to the self-renewal of cancer cells through functional mining of the unique gene expression signature of cells immortalized by c-MYC. Cell Cycle. 2011 Aug 1;10(15).
2011-08-04 | GSE31002 | GEO
Project description:Cultured cancer cells exhibit substantial phenotypic heterogeneity when measured in a variety of ways such as sensitivity to drugs or the capacity to grow under various conditions. Among these, the ability to exhibit anchorage-independent cell growth (colony forming capacity in semisolid media) has been considered to be fundamental in cancer biology because it has been connected with tumor cell aggressiveness in vivo such as tumorigenic and metastatic potentials, and also utilized as a marker for in vitro transformation. Although multiple genetic factors for anchorage-independence have been identified, the molecular basis for this capacity is still largely unknown. To investigate the molecular mechanisms underlying anchorage-independent cell growth, we have used genome-wide DNA microarray studies to develop an expression signature associated with this phenotype. Using this signature, we identify a program of activated mitochondrial biogenesis associated with the phenotype of anchorage-independent growth and importantly, we demonstrate that this phenotype predicts potential for metastasis in primary breast and lung tumors. Keywords: c-Myc or v-Src retroviral vector-infected immortalized mouse embryonic fibroblasts. Expression data of c-Myc and v-Src transformed MEFs was used to validate an expression signature generated from human cultured breast cancer cell lines with anchorage-independent growth ability.
2009-04-10 | E-GEOD-15161 | biostudies-arrayexpress
Project description:BACKGROUND: The MYC oncogene contributes to induction and growth of many cancers but the full spectrum of the MYC transcriptional response remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: Using microarrays, we conducted a detailed kinetic study of genes that respond to MYCN or MYCNDeltaMBII induction in primary human fibroblasts. In parallel, we determined the response to steady state overexpression of MYCN and MYCNDeltaMBII in the same cell type. An overlapping set of 398 genes from the two protocols was designated a 'Core MYC Signature' and used for further analysis. Comparison of the Core MYC Signature to a published study of the genes induced by serum stimulation revealed that only 7.4% of the Core MYC Signature genes are in the Core Serum Response and display similar expression changes to both MYC and serum. Furthermore, more than 50% of the Core MYC Signature genes were not influenced by serum stimulation. In contrast, comparison to a panel of breast cancers revealed a strong concordance in gene expression between the Core MYC Signature and the basal-like breast tumor subtype, which is a subtype with poor prognosis. This concordance was supported by the higher average level of MYC expression in the same tumor samples. CONCLUSIONS/SIGNIFICANCE: The Core MYC Signature has clinical relevance as this profile can be used to deduce an underlying genetic program that is likely to contribute to a clinical phenotype. Therefore, the presence of the Core MYC Signature may predict clinical responsiveness to therapeutics that are designed to disrupt MYC-mediated phenotypes. reference X sample
2010-06-23 | E-GEOD-15523 | biostudies-arrayexpress
Project description:RNA-binding proteins control gene expression in cardiac fibroblasts during TGFb-driven fibrotic responses, including the eukaryotic translation initiation factor 4G2 (eIF4G2), which was known to facilitate alternative mRNA translation during cellular stresses. However, the precise role of eIF4G2 in cardiac fibroblast activation in response to fibrotic stress remains unclear. In this study, we found increased eIF4G2 protein levels in the hearts of heart failure patients and myocardial infarcted mice, as well as in TGFb-treated immortalized human and primary mouse cardiac fibroblasts. Depletion of eIF4G2 led to predominant translational downregulation of genes that are enriched in focal adhesion and extracellular matrix pathways. eIF4G2 knockdown reduced the proliferation, migration, and collagen secretion of TGFb-treated cardiac fibroblasts. Mechanistically, we found that the translation of IGFBP7 mRNA relies on eIF4G2, which is crucial for ECM production in response to pro-fibrotic stimuli. The interaction between eIF4G2 and a DEAD box RNA helicase DDX24 can regulate IGFBP7 protein expression in cardiac fibroblasts. Together, these findings suggest that the TGFb-eIF4G2-IGFBP7 axis establishes a novel translational regulatory circuit that governs cardiac fibroblast activation. Furthermore, conditional knockout of Eif4g2 in POSTN-positive myofibroblasts reduced cardiac fibrosis in the myocardial infarction mouse model, thus improving cardiac function. Our study provides insights into the molecular mechanism of eIF4G2-mediated translational regulation of crucial physiological mRNAs during cardiac fibroblast activation.
2024-07-31 | GSE239824 | GEO
Project description:RNA-binding proteins control gene expression in cardiac fibroblasts during TGFb-driven fibrotic responses, including the eukaryotic translation initiation factor 4G2 (eIF4G2), which was known to facilitate alternative mRNA translation during cellular stresses. However, the precise role of eIF4G2 in cardiac fibroblast activation in response to fibrotic stress remains unclear. In this study, we found increased eIF4G2 protein levels in the hearts of heart failure patients and myocardial infarcted mice, as well as in TGFb-treated immortalized human and primary mouse cardiac fibroblasts. Depletion of eIF4G2 led to predominant translational downregulation of genes that are enriched in focal adhesion and extracellular matrix pathways. eIF4G2 knockdown reduced the proliferation, migration, and collagen secretion of TGFb-treated cardiac fibroblasts. Mechanistically, we found that the translation of IGFBP7 mRNA relies on eIF4G2, which is crucial for ECM production in response to pro-fibrotic stimuli. The interaction between eIF4G2 and a DEAD box RNA helicase DDX24 can regulate IGFBP7 protein expression in cardiac fibroblasts. Together, these findings suggest that the TGFb-eIF4G2-IGFBP7 axis establishes a novel translational regulatory circuit that governs cardiac fibroblast activation. Furthermore, conditional knockout of Eif4g2 in POSTN-positive myofibroblasts reduced cardiac fibrosis in the myocardial infarction mouse model, thus improving cardiac function. Our study provides insights into the molecular mechanism of eIF4G2-mediated translational regulation of crucial physiological mRNAs during cardiac fibroblast activation.
2024-07-31 | GSE239823 | GEO
Project description:Myc, a member of the Myc Network, supervises proliferation, metabolism and ribosomal function. The Mlx Network cross-talks with the Myc Network and regulates overlapping functions. We describe here the consequences of conditional Myc and/or Mlx gene knockouts (KOs) in primary and immortalized murine embryonic fibroblasts (MEFs). MycKO and MycKOxMlxKO “double KO” (DKO) primary MEFs, but not MlxKO MEFs, rapidly growth-arrested and displayed features of aging and senescence. In DKO MEFs, these were transient, indicating that Mlx was necessary to maintain them. KO MEFs deregulated transcripts pertaining to mitochondrial and ribosomal structure and function, cell cycle, aging, senescence and DNA damage. The expression of DNA damage-related proteins was also abnormal. Immortalized KO MEFs remained proliferation-competent but demonstrated differential sensitivities to genotoxic agents. Immortalized MycKO MEFs spontaneously developed tetraploidy that was Mlx-dependent. Different aspects of MEF aging, senescence and DNA damage responses are therefore differentially regulated by the Myc and Mlx Networks.
2023-08-28 | GSE210362 | GEO
Project description:BACKGROUND: The MYC oncogene contributes to induction and growth of many cancers but the full spectrum of the MYC transcriptional response remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: Using microarrays, we conducted a detailed kinetic study of genes that respond to MYCN or MYCNDeltaMBII induction in primary human fibroblasts. In parallel, we determined the response to steady state overexpression of MYCN and MYCNDeltaMBII in the same cell type. An overlapping set of 398 genes from the two protocols was designated a 'Core MYC Signature' and used for further analysis. Comparison of the Core MYC Signature to a published study of the genes induced by serum stimulation revealed that only 7.4% of the Core MYC Signature genes are in the Core Serum Response and display similar expression changes to both MYC and serum. Furthermore, more than 50% of the Core MYC Signature genes were not influenced by serum stimulation. In contrast, comparison to a panel of breast cancers revealed a strong concordance in gene expression between the Core MYC Signature and the basal-like breast tumor subtype, which is a subtype with poor prognosis. This concordance was supported by the higher average level of MYC expression in the same tumor samples. CONCLUSIONS/SIGNIFICANCE: The Core MYC Signature has clinical relevance as this profile can be used to deduce an underlying genetic program that is likely to contribute to a clinical phenotype. Therefore, the presence of the Core MYC Signature may predict clinical responsiveness to therapeutics that are designed to disrupt MYC-mediated phenotypes.
2009-09-22 | GSE15523 | GEO
Project description:To address the question of whether v-myc modifies the stemness and potency of hNSCs, we first studied the expression of 90 genes related to stemness, self-renewal and differentiation in several v-myc immortalized cell lines (hNS1, hVM1, hCTX), non-immortalized neurospheres (hNPC derived from 9.5 and 10 weeks-old fetuses), hESCs (H9 and HS181) and human foreskin fibroblasts (hFF-1).
2014-11-29 | GSE63710 | GEO