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Kohler R, Engeland K. A-MYB substitutes for B-MYB in activating cell cycle genes and in stimulating proliferation. Nucleic Acids Res 2024; 52:6830-6849. [PMID: 38747345 PMCID: PMC11229319 DOI: 10.1093/nar/gkae370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 04/15/2024] [Accepted: 04/24/2024] [Indexed: 07/09/2024] Open
Abstract
A-MYB (MYBL1) is a transcription factor with a role in meiosis in spermatocytes. The related B-MYB protein is a key oncogene and a master regulator activating late cell cycle genes. To activate genes, B-MYB forms a complex with MuvB and is recruited indirectly to cell cycle genes homology region (CHR) promoter sites of target genes. Activation through the B-MYB-MuvB (MMB) complex is essential for successful mitosis. Here, we discover that A-MYB has a function in transcriptional regulation of the mitotic cell cycle and can substitute for B-MYB. Knockdown experiments in cells not related to spermatogenesis show that B-MYB loss alone merely delays cell cycle progression. Only dual knockdown of B-MYB and A-MYB causes G2/M cell cycle arrest, endoreduplication, and apoptosis. A-MYB can substitute for B-MYB in binding to MuvB. The resulting A-MYB-MuvB complex activates genes through CHR sites. We find that A-MYB activates the same target genes as B-MYB. Many of the corresponding proteins are central regulators of the cell division cycle. In summary, we demonstrate that A-MYB is an activator of the mitotic cell cycle by activating late cell cycle genes.
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Affiliation(s)
- Robin Kohler
- Molecular Oncology, Medical School, University of Leipzig, Semmelweisstr. 14, 04103 Leipzig, Germany
| | - Kurt Engeland
- Molecular Oncology, Medical School, University of Leipzig, Semmelweisstr. 14, 04103 Leipzig, Germany
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2
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Fischer M. Gene regulation by the tumor suppressor p53 - The omics era. Biochim Biophys Acta Rev Cancer 2024; 1879:189111. [PMID: 38740351 DOI: 10.1016/j.bbcan.2024.189111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 05/08/2024] [Accepted: 05/10/2024] [Indexed: 05/16/2024]
Abstract
The transcription factor p53 is activated in response to a variety of cellular stresses and serves as a prominent and potent tumor suppressor. Since its discovery, we have sought to understand how p53 functions as both a transcription factor and a tumor suppressor. Two decades ago, the field of gene regulation entered the omics era and began to study the regulation of entire genomes. The omics perspective has greatly expanded our understanding of p53 functions and has begun to reveal its gene regulatory network. In this mini-review, I discuss recent insights into the p53 transcriptional program from high-throughput analyses.
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Affiliation(s)
- Martin Fischer
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany.
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3
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Humayun A, Lin LYT, Li HH, Fornace AJ. FAILLA MEMORIAL LECTURE How We Got Here: One Laboratory's Odyssey in the Field of Radiation-Inducible Genes. Radiat Res 2024; 201:617-627. [PMID: 38573158 DOI: 10.1667/rade-23-00205.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/11/2024] [Indexed: 04/05/2024]
Abstract
This review focuses on early discoveries that contributed to our understanding and the scope of transcriptional responses after radiation damage. Before the development of modern approaches to assess overall global transcriptomic responses, the idea that mammalian cells could respond to DNA-damaging agents in a manner analogous to bacteria was not generally accepted. To investigate this possibility, the development of technology to identify differentially expressed low-abundance transcripts substantially facilitated our appreciation that DNA damaging agents like UV radiation and subsequently ionizing radiation did in fact produce robust transcriptional responses. Here we focus on our identification and characterization of radiation-inducible genes, and how even early studies on stress gene signaling highlighted the broad scope of transcriptional responses to radiation damage. Since then, the central role of transcriptional responses to radiation injury in maintaining genome integrity has been highlighted in many processes, including cell cycle checkpoint control, resistance to cancer by p53 and other key factors, cell senescence, and metabolism.
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Affiliation(s)
- Arslon Humayun
- Department of Oncology, Lombardi Comprehensive Cancer Center, Washington, DC
| | | | - Heng-Hong Li
- Department of Oncology, Lombardi Comprehensive Cancer Center, Washington, DC
| | - Albert J Fornace
- Department of Oncology, Lombardi Comprehensive Cancer Center, Washington, DC
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC
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4
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Abad E, Sandoz J, Romero G, Zadra I, Urgel-Solas J, Borredat P, Kourtis S, Ortet L, Martínez CM, Weghorn D, Sdelci S, Janic A. The TP53-activated E3 ligase RNF144B is a tumour suppressor that prevents genomic instability. J Exp Clin Cancer Res 2024; 43:127. [PMID: 38685100 PMCID: PMC11057071 DOI: 10.1186/s13046-024-03045-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 04/11/2024] [Indexed: 05/02/2024] Open
Abstract
BACKGROUND TP53, the most frequently mutated gene in human cancers, orchestrates a complex transcriptional program crucial for cancer prevention. While certain TP53-dependent genes have been extensively studied, others, like the recently identified RNF144B, remained poorly understood. This E3 ubiquitin ligase has shown potent tumor suppressor activity in murine Eμ Myc-driven lymphoma, emphasizing its significance in the TP53 network. However, little is known about its targets and its role in cancer development, requiring further exploration. In this work, we investigate RNF144B's impact on tumor suppression beyond the hematopoietic compartment in human cancers. METHODS Employing TP53 wild-type cells, we generated models lacking RNF144B in both non-transformed and cancerous cells of human and mouse origin. By using proteomics, transcriptomics, and functional analysis, we assessed RNF144B's impact in cellular proliferation and transformation. Through in vitro and in vivo experiments, we explored proliferation, DNA repair, cell cycle control, mitotic progression, and treatment resistance. Findings were contrasted with clinical datasets and bioinformatics analysis. RESULTS Our research underscores RNF144B's pivotal role as a tumor suppressor, particularly in lung adenocarcinoma. In both human and mouse oncogene-expressing cells, RNF144B deficiency heightened cellular proliferation and transformation. Proteomic and transcriptomic analysis revealed RNF144B's novel function in mediating protein degradation associated with cell cycle progression, DNA damage response and genomic stability. RNF144B deficiency induced chromosomal instability, mitotic defects, and correlated with elevated aneuploidy and worse prognosis in human tumors. Furthermore, RNF144B-deficient lung adenocarcinoma cells exhibited resistance to cell cycle inhibitors that induce chromosomal instability. CONCLUSIONS Supported by clinical data, our study suggests that RNF144B plays a pivotal role in maintaining genomic stability during tumor suppression.
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Affiliation(s)
- Etna Abad
- Department of Medicine and Life Sciences, Universidad Pompeu Fabra, Barcelona, 08003, Spain
| | - Jérémy Sandoz
- Department of Medicine and Life Sciences, Universidad Pompeu Fabra, Barcelona, 08003, Spain
| | - Gerard Romero
- Department of Medicine and Life Sciences, Universidad Pompeu Fabra, Barcelona, 08003, Spain
- Thoracic Cancers Translational Genomics Unit, Vall d'Hebron Institute of Oncology (VHIO), Barcelona, 08035, Spain
| | - Ivan Zadra
- Department of Medicine and Life Sciences, Universidad Pompeu Fabra, Barcelona, 08003, Spain
| | - Julia Urgel-Solas
- Department of Medicine and Life Sciences, Universidad Pompeu Fabra, Barcelona, 08003, Spain
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, 08003, Spain
| | - Pablo Borredat
- Department of Medicine and Life Sciences, Universidad Pompeu Fabra, Barcelona, 08003, Spain
| | - Savvas Kourtis
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, 08003, Spain
| | - Laura Ortet
- Department of Medicine and Life Sciences, Universidad Pompeu Fabra, Barcelona, 08003, Spain
| | - Carlos M Martínez
- Pathology Platform, Instituto Murciano de Investigación Biosanitaria (IMIB-Pascual Parrilla), Murcia, 30120, Spain
| | - Donate Weghorn
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, 08003, Spain
| | - Sara Sdelci
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, 08003, Spain
| | - Ana Janic
- Department of Medicine and Life Sciences, Universidad Pompeu Fabra, Barcelona, 08003, Spain.
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5
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Łasut-Szyszka B, Gdowicz-Kłosok A, Małachowska B, Krześniak M, Będzińska A, Gawin M, Pietrowska M, Rusin M. Transcriptomic and proteomic study of cancer cell lines exposed to actinomycin D and nutlin-3a reveals numerous, novel candidates for p53-regulated genes. Chem Biol Interact 2024; 392:110946. [PMID: 38460933 DOI: 10.1016/j.cbi.2024.110946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 02/28/2024] [Accepted: 03/06/2024] [Indexed: 03/11/2024]
Abstract
Transcriptomic analyses have revealed hundreds of p53-regulated genes; however, these studies used a limited number of cell lines and p53-activating agents. Therefore, we searched for candidate p53-target genes by employing stress factors and cell lines never before used in a high-throughput search for p53-regulated genes. We performed RNA-Seq on A549 cells exposed to camptothecin, actinomycin D, nutlin-3a, as well as a combination of actinomycin D and nutlin-3a (A + N). The latter two substances synergise upon the activation of selected p53-target genes. A similar analysis was performed on other cell lines (U-2 OS, NCI-H460, A375) exposed to A + N. To identify proteins in cell lysates or those secreted into a medium of A549 cells in control conditions or treated with A + N, we employed mass spectrometry. The expression of selected genes strongly upregulated by A + N or camptothecin was examined by RT-PCR in p53-deficient cells and their controls. We found that p53 participates in the upregulation of: ACP5, APOL3, CDH3, CIBAR2, CRABP2, CTHRC1, CTSH, FAM13C, FBXO2, FRMD8, FRZB, GAST, ICOSLG, KANK3, KCNK6, KLRG2, MAFB, MR1, NDRG4, PTAFR, RETSAT, TMEM52, TNFRSF14, TRANK1, TYSND1, WFDC2, WFDC5, WNT4 genes. Twelve of these proteins were detected in the secretome and/or proteome of treated cells. Our data generated new hypotheses concerning the functioning of p53. Many genes activated by A + N or camptothecin are also activated by interferons, indicating a noticeable overlap between transcriptional programs of p53 and these antiviral cytokines. Moreover, several identified genes code for antagonists of WNT/β-catenin signalling pathways, which suggests new connections between these two cancer-related signalling systems. One of these antagonists is DRAXIN. Previously, we found that its gene is activated by p53. In this study, using mass spectrometry and Western blotting, we detected expression of DRAXIN in a medium of A549 cells exposed to A + N. Thus, this protein functions not only in the development of the nervous system, but it may also have a new cancer-related function.
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Affiliation(s)
- Barbara Łasut-Szyszka
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101, Gliwice, Poland
| | - Agnieszka Gdowicz-Kłosok
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101, Gliwice, Poland
| | - Beata Małachowska
- Department of Radiation Oncology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY, 10461, USA
| | - Małgorzata Krześniak
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101, Gliwice, Poland
| | - Agnieszka Będzińska
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101, Gliwice, Poland
| | - Marta Gawin
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101, Gliwice, Poland
| | - Monika Pietrowska
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101, Gliwice, Poland
| | - Marek Rusin
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101, Gliwice, Poland.
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6
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Rodencal J, Kim N, He A, Li VL, Lange M, He J, Tarangelo A, Schafer ZT, Olzmann JA, Long JZ, Sage J, Dixon SJ. Sensitization of cancer cells to ferroptosis coincident with cell cycle arrest. Cell Chem Biol 2024; 31:234-248.e13. [PMID: 37963466 PMCID: PMC10925838 DOI: 10.1016/j.chembiol.2023.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/19/2023] [Accepted: 10/13/2023] [Indexed: 11/16/2023]
Abstract
Ferroptosis is a non-apoptotic form of cell death that can be triggered by inhibiting the system xc- cystine/glutamate antiporter or the phospholipid hydroperoxidase glutathione peroxidase 4 (GPX4). We have investigated how cell cycle arrest caused by stabilization of p53 or inhibition of cyclin-dependent kinase 4/6 (CDK4/6) impacts ferroptosis sensitivity. Here, we show that cell cycle arrest can enhance sensitivity to ferroptosis induced by covalent GPX4 inhibitors (GPX4i) but not system xc- inhibitors. Greater sensitivity to GPX4i is associated with increased levels of oxidizable polyunsaturated fatty acid-containing phospholipids (PUFA-PLs). Higher PUFA-PL abundance upon cell cycle arrest involves reduced expression of membrane-bound O-acyltransferase domain-containing 1 (MBOAT1) and epithelial membrane protein 2 (EMP2). A candidate orally bioavailable GPX4 inhibitor increases lipid peroxidation and shrinks tumor volumes when combined with a CDK4/6 inhibitor. Thus, cell cycle arrest may make certain cancer cells more susceptible to ferroptosis in vivo.
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Affiliation(s)
- Jason Rodencal
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Nathan Kim
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Andrew He
- Departments of Pediatrics and Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Veronica L Li
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Sarafan ChEM-H, Stanford University, Stanford, CA 94035, USA
| | - Mike Lange
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jianping He
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Amy Tarangelo
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Zachary T Schafer
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - James A Olzmann
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Jonathan Z Long
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Sarafan ChEM-H, Stanford University, Stanford, CA 94035, USA
| | - Julien Sage
- Departments of Pediatrics and Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Scott J Dixon
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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Rakotopare J, Toledo F. p53 in the Molecular Circuitry of Bone Marrow Failure Syndromes. Int J Mol Sci 2023; 24:14940. [PMID: 37834388 PMCID: PMC10573108 DOI: 10.3390/ijms241914940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Mice with a constitutive increase in p53 activity exhibited features of dyskeratosis congenita (DC), a bone marrow failure syndrome (BMFS) caused by defective telomere maintenance. Further studies confirmed, in humans and mice, that germline mutations affecting TP53 or its regulator MDM4 may cause short telomeres and alter hematopoiesis, but also revealed features of Diamond-Blackfan anemia (DBA) or Fanconi anemia (FA), two BMFSs, respectively, caused by defects in ribosomal function or DNA repair. p53 downregulates several genes mutated in DC, either by binding to promoter sequences (DKC1) or indirectly via the DREAM repressor complex (RTEL1, DCLRE1B), and the p53-DREAM pathway represses 22 additional telomere-related genes. Interestingly, mutations in any DC-causal gene will cause telomere dysfunction and subsequent p53 activation to further promote the repression of p53-DREAM targets. Similarly, ribosomal dysfunction and DNA lesions cause p53 activation, and p53-DREAM targets include the DBA-causal gene TSR2, at least 9 FA-causal genes, and 38 other genes affecting ribosomes or the FA pathway. Furthermore, patients with BMFSs may exhibit brain abnormalities, and p53-DREAM represses 16 genes mutated in microcephaly or cerebellar hypoplasia. In sum, positive feedback loops and the repertoire of p53-DREAM targets likely contribute to partial phenotypic overlaps between BMFSs of distinct molecular origins.
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Affiliation(s)
- Jeanne Rakotopare
- Genetics of Tumor Suppression, Institut Curie, CEDEX 05, 75248 Paris, France;
- CNRS UMR3244, 75005 Paris, France
- Faculty of Science and Engineering, Sorbonne University, 75005 Paris, France
- Institut Curie, PSL Research University, 75005 Paris, France
| | - Franck Toledo
- Genetics of Tumor Suppression, Institut Curie, CEDEX 05, 75248 Paris, France;
- CNRS UMR3244, 75005 Paris, France
- Faculty of Science and Engineering, Sorbonne University, 75005 Paris, France
- Institut Curie, PSL Research University, 75005 Paris, France
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8
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Rakotopare J, Lejour V, Duval C, Eldawra E, Escoffier H, Toledo F. A systematic approach identifies p53-DREAM pathway target genes associated with blood or brain abnormalities. Dis Model Mech 2023; 16:dmm050376. [PMID: 37661832 PMCID: PMC10581385 DOI: 10.1242/dmm.050376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/21/2023] [Indexed: 09/05/2023] Open
Abstract
p53 (encoded by Trp53) is a tumor suppressor, but mouse models have revealed that increased p53 activity may cause bone marrow failure, likely through dimerization partner, RB-like, E2F4/E2F5 and MuvB (DREAM) complex-mediated gene repression. Here, we designed a systematic approach to identify p53-DREAM pathway targets, the repression of which might contribute to abnormal hematopoiesis. We used Gene Ontology analysis to study transcriptomic changes associated with bone marrow cell differentiation, then chromatin immunoprecipitation-sequencing (ChIP-seq) data to identify DREAM-bound promoters. We next created positional frequency matrices to identify evolutionary conserved sequence elements potentially bound by DREAM. The same approach was developed to find p53-DREAM targets associated with brain abnormalities, also observed in mice with increased p53 activity. Putative DREAM-binding sites were found for 151 candidate target genes, of which 106 are mutated in a blood or brain genetic disorder. Twenty-one DREAM-binding sites were tested and found to impact gene expression in luciferase assays, to notably regulate genes mutated in dyskeratosis congenita (Rtel1), Fanconi anemia (Fanca), Diamond-Blackfan anemia (Tsr2), primary microcephaly [Casc5 (or Knl1), Ncaph and Wdr62] and pontocerebellar hypoplasia (Toe1). These results provide clues on the role of the p53-DREAM pathway in regulating hematopoiesis and brain development, with implications for tumorigenesis.
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Affiliation(s)
- Jeanne Rakotopare
- Genetics of Tumor Suppression, Institut Curie, Paris 75248 Cedex 05, France
- CNRS UMR3244, Paris 75005, France
- Sorbonne University, Paris 75005, France
- PSL Research University, Paris 75005, France
| | - Vincent Lejour
- Genetics of Tumor Suppression, Institut Curie, Paris 75248 Cedex 05, France
- CNRS UMR3244, Paris 75005, France
- Sorbonne University, Paris 75005, France
- PSL Research University, Paris 75005, France
| | - Carla Duval
- Genetics of Tumor Suppression, Institut Curie, Paris 75248 Cedex 05, France
- CNRS UMR3244, Paris 75005, France
- Sorbonne University, Paris 75005, France
- PSL Research University, Paris 75005, France
| | - Eliana Eldawra
- Genetics of Tumor Suppression, Institut Curie, Paris 75248 Cedex 05, France
- CNRS UMR3244, Paris 75005, France
- Sorbonne University, Paris 75005, France
- PSL Research University, Paris 75005, France
| | | | - Franck Toledo
- Genetics of Tumor Suppression, Institut Curie, Paris 75248 Cedex 05, France
- CNRS UMR3244, Paris 75005, France
- Sorbonne University, Paris 75005, France
- PSL Research University, Paris 75005, France
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9
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Rodencal J, Kim N, Li VL, He A, Lange M, He J, Tarangelo A, Schafer ZT, Olzmann JA, Sage J, Long JZ, Dixon SJ. A Cell Cycle-Dependent Ferroptosis Sensitivity Switch Governed by EMP2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.19.549715. [PMID: 37502927 PMCID: PMC10370086 DOI: 10.1101/2023.07.19.549715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Ferroptosis is a non-apoptotic form of cell death characterized by iron-dependent lipid peroxidation. Ferroptosis can be induced by system xc- cystine/glutamate antiporter inhibition or by direct inhibition of the phospholipid hydroperoxidase glutathione peroxidase 4 (GPX4). The regulation of ferroptosis in response to system xc- inhibition versus direct GPX4 inhibition may be distinct. Here, we show that cell cycle arrest enhances sensitivity to ferroptosis triggered by GPX4 inhibition but not system xc- inhibition. Arrested cells have increased levels of oxidizable polyunsaturated fatty acid-containing phospholipids, which drives sensitivity to GPX4 inhibition. Epithelial membrane protein 2 (EMP2) expression is reduced upon cell cycle arrest and is sufficient to enhance ferroptosis in response to direct GPX4 inhibition. An orally bioavailable GPX4 inhibitor increased markers of ferroptotic lipid peroxidation in vivo in combination with a cell cycle arresting agent. Thus, responses to different ferroptosis-inducing stimuli can be regulated by cell cycle state.
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Affiliation(s)
- Jason Rodencal
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Nathan Kim
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Veronica L. Li
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew He
- Departments of Pediatrics and Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mike Lange
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jianping He
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Amy Tarangelo
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Zachary T. Schafer
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - James A. Olzmann
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Julien Sage
- Departments of Pediatrics and Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jonathan Z. Long
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Scott J. Dixon
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Lead contact
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10
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Kandhaya-Pillai R, Miro-Mur F, Alijotas-Reig J, Tchkonia T, Schwartz S, Kirkland JL, Oshima J. Key elements of cellular senescence involve transcriptional repression of mitotic and DNA repair genes through the p53-p16/RB-E2F-DREAM complex. Aging (Albany NY) 2023; 15:4012-4034. [PMID: 37219418 PMCID: PMC10258023 DOI: 10.18632/aging.204743] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 05/03/2023] [Indexed: 05/24/2023]
Abstract
Cellular senescence is a dynamic stress response process that contributes to aging. From initiation to maintenance, senescent cells continuously undergo complex molecular changes and develop an altered transcriptome. Understanding how the molecular architecture of these cells evolve to sustain their non-proliferative state will open new therapeutic avenues to alleviate or delay the consequences of aging. Seeking to understand these molecular changes, we studied the transcriptomic profiles of endothelial replication-induced senescence and senescence induced by the inflammatory cytokine, TNF-α. We previously reported gene expressional pattern, pathways, and the mechanisms associated with upregulated genes during TNF-α induced senescence. Here, we extend our work and find downregulated gene signatures of both replicative and TNF-α senescence were highly overlapped, involving the decreased expression of several genes associated with cell cycle regulation, DNA replication, recombination, repair, chromatin structure, cellular assembly, and organization. We identified multiple targets of p53/p16-RB-E2F-DREAM that are essential for proliferation, mitotic progression, resolving DNA damage, maintaining chromatin integrity, and DNA synthesis that were repressed in senescent cells. We show that repression of multiple target genes in the p53/p16-RB-E2F-DREAM pathway collectively contributes to the stability of the senescent arrest. Our findings show that the regulatory connection between DREAM and cellular senescence may play a potential role in the aging process.
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Affiliation(s)
- Renuka Kandhaya-Pillai
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
- Systemic Autoimmune Diseases Research Unit, Vall d’Hebron Research Institute (VHIR), Barcelona 08035, Spain
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
| | - Francesc Miro-Mur
- Systemic Autoimmune Diseases Research Unit, Vall d’Hebron Research Institute (VHIR), Barcelona 08035, Spain
| | - Jaume Alijotas-Reig
- Systemic Autoimmune Diseases Research Unit, Vall d’Hebron Research Institute (VHIR), Barcelona 08035, Spain
| | - Tamar Tchkonia
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
- Department of Physiology, Mayo Clinic, Rochester, MN 55905, USA
| | - Simo Schwartz
- Drug Delivery and Targeting Group, Clinical Biochemistry Department, Vall d’Hebron Hospital, Barcelona 08035, Spain
| | - James L. Kirkland
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
- Department of Physiology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Junko Oshima
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
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Łasut-Szyszka B, Rusin M. The Wheel of p53 Helps to Drive the Immune System. Int J Mol Sci 2023; 24:ijms24087645. [PMID: 37108808 PMCID: PMC10143509 DOI: 10.3390/ijms24087645] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/18/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
The p53 tumor suppressor protein is best known as an inhibitor of the cell cycle and an inducer of apoptosis. Unexpectedly, these functions of p53 are not required for its tumor suppressive activity in animal models. High-throughput transcriptomic investigations as well as individual studies have demonstrated that p53 stimulates expression of many genes involved in immunity. Probably to interfere with its immunostimulatory role, many viruses code for proteins that inactivate p53. Judging by the activities of immunity-related p53-regulated genes it can be concluded that p53 is involved in detection of danger signals, inflammasome formation and activation, antigen presentation, activation of natural killer cells and other effectors of immunity, stimulation of interferon production, direct inhibition of virus replication, secretion of extracellular signaling molecules, production of antibacterial proteins, negative feedback loops in immunity-related signaling pathways, and immunologic tolerance. Many of these p53 functions have barely been studied and require further, more detailed investigations. Some of them appear to be cell-type specific. The results of transcriptomic studies have generated many new hypotheses on the mechanisms utilized by p53 to impact on the immune system. In the future, these mechanisms may be harnessed to fight cancer and infectious diseases.
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Affiliation(s)
- Barbara Łasut-Szyszka
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101 Gliwice, Poland
| | - Marek Rusin
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101 Gliwice, Poland
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12
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Schwab K, Coronel L, Riege K, Sacramento EK, Rahnis N, Häckes D, Cirri E, Groth M, Hoffmann S, Fischer M. Multi-omics analysis identifies RFX7 targets involved in tumor suppression and neuronal processes. Cell Death Discov 2023; 9:80. [PMID: 36864036 PMCID: PMC9981735 DOI: 10.1038/s41420-023-01378-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/19/2023] [Accepted: 02/22/2023] [Indexed: 03/04/2023] Open
Abstract
Recurrently mutated in lymphoid neoplasms, the transcription factor RFX7 is emerging as a tumor suppressor. Previous reports suggested that RFX7 may also have a role in neurological and metabolic disorders. We recently reported that RFX7 responds to p53 signaling and cellular stress. Furthermore, we found RFX7 target genes to be dysregulated in numerous cancer types also beyond the hematological system. However, our understanding of RFX7's target gene network and its role in health and disease remains limited. Here, we generated RFX7 knock-out cells and employed a multi-omics approach integrating transcriptome, cistrome, and proteome data to obtain a more comprehensive picture of RFX7 targets. We identify novel target genes linked to RFX7's tumor suppressor function and underscoring its potential role in neurological disorders. Importantly, our data reveal RFX7 as a mechanistic link that enables the activation of these genes in response to p53 signaling.
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Affiliation(s)
- Katjana Schwab
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Luis Coronel
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Konstantin Riege
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Erika K. Sacramento
- grid.418245.e0000 0000 9999 5706Core Facility for Proteomics, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Norman Rahnis
- grid.418245.e0000 0000 9999 5706Core Facility for Proteomics, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - David Häckes
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Emilio Cirri
- grid.418245.e0000 0000 9999 5706Core Facility for Proteomics, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Marco Groth
- grid.418245.e0000 0000 9999 5706Core Facility for Next-Generation Sequencing, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Steve Hoffmann
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Martin Fischer
- Computational Biology Group, Leibniz Institute on Aging-Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745, Jena, Germany.
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13
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Fischer M, Riege K, Hoffmann S. The landscape of human p53-regulated long non-coding RNAs reveals critical host gene co-regulation. Mol Oncol 2023. [PMID: 36852646 DOI: 10.1002/1878-0261.13405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/20/2023] [Accepted: 02/27/2023] [Indexed: 03/01/2023] Open
Abstract
The role of long non-coding RNAs (lncRNAs) in p53-mediated tumor suppression has become increasingly appreciated in the past decade. Thus, the identification of p53-regulated lncRNAs can be a promising starting point to select and prioritize lncRNAs for functional analyses. By integrating transcriptome and transcription factor-binding data, we identified 379 lncRNAs that are recurrently differentially regulated by p53. Dissecting the mechanisms by which p53 regulates many of them, we identified sets of lncRNAs regulated either directly by p53 or indirectly through the p53-RFX7 and p53-p21-DREAM/RB:E2F pathways. Importantly, we identified multiple p53-responsive lncRNAs that are co-regulated with their protein-coding host genes, revealing an important mechanism by which p53 may regulate lncRNAs. Further analysis of transcriptome data and clinical data from cancer patients showed that recurrently p53-regulated lncRNAs are associated with patient survival. Together, the integrative analysis of the landscape of p53-regulated lncRNAs provides a powerful resource facilitating the identification of lncRNA function and displays the mechanisms of p53-dependent regulation that could be exploited for developing anticancer approaches.
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Affiliation(s)
- Martin Fischer
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Konstantin Riege
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
| | - Steve Hoffmann
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
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14
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Kaller M, Shi W, Hermeking H. c-MYC-Induced AP4 Attenuates DREAM-Mediated Repression by p53. Cancers (Basel) 2023; 15:cancers15041162. [PMID: 36831504 PMCID: PMC9954515 DOI: 10.3390/cancers15041162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023] Open
Abstract
BACKGROUND The deregulated expression of the c-MYC oncogene activates p53, which is presumably mediated by ARF/INK4, as well as replication-stress-induced DNA damage. Here, we aimed to determine whether the c-MYC-inducible AP4 transcription factor plays a role in this context using a genetic approach. METHODS We used a CRISPR/Cas9 approach to generate AP4- and/or p53-deficient derivatives of MCF-7 breast cancer cells harboring an ectopic, inducible c-MYC allele. Cell proliferation, senescence, DNA damage, and comprehensive RNA expression profiles were determined after activation of c-MYC. In addition, we analyzed the expression data from primary breast cancer samples. RESULTS Loss of AP4 resulted in elevated levels of both spontaneous and c-MYC-induced DNA damage, senescence, and diminished cell proliferation. Deletion of p53 in AP4-deficient cells reverted senescence and proliferation defects without affecting DNA damage levels. RNA-Seq analyses showed that loss of AP4 enhanced repression of DREAM and E2F target genes after p53 activation by c-MYC. Depletion of p21 or the DREAM complex component LIN37 abrogated this effect. These p53-dependent effects were conserved on the level of clinical and gene expression associations found in primary breast cancer tumors. CONCLUSIONS Our results establish AP4 as a pivotal factor at the crossroads of c-MYC, E2F, and p53 target gene regulation.
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Affiliation(s)
- Markus Kaller
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig-Maximilians-University München, D-80337 Munich, Germany
| | - Wenjing Shi
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig-Maximilians-University München, D-80337 Munich, Germany
| | - Heiko Hermeking
- Experimental and Molecular Pathology, Institute of Pathology, Ludwig-Maximilians-University München, D-80337 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, D-80336 Munich, Germany
- German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
- Correspondence: ; Tel.: +49-89-2180-73685; Fax: +49-89-2180-73697
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15
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Panatta E, Butera A, Celardo I, Leist M, Melino G, Amelio I. p53 regulates expression of nuclear envelope components in cancer cells. Biol Direct 2022; 17:38. [PMID: 36461070 PMCID: PMC9716746 DOI: 10.1186/s13062-022-00349-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 12/03/2022] Open
Abstract
Nuclear organisation and architecture are essential for the maintenance of genomic integrity as well as for the epigenetic regulations and gene expression. Disruption of lamin B1, major structural and functional member of the nuclear lamina, is observed in human laminopathies and in sporadic cancers, and leads to chromosomal rearrangements and alterations of gene expression. The tumour suppressor p53 has been shown to direct specific transcriptional programmes by regulating lamin A/C, however its relationship with lamin B1 has remained elusive. Here, we show that loss of p53 correlates with increased expression of members belonging to the nuclear pore complex and nuclear lamina and directly regulates transcription of lamin B1. We show that the genomic loci of a fraction of p53-dependent genes physically interact with lamin B1 and Nup210. This observation provides a possible mechanistic explanation for the p53-depedent changes of chromatin accessibility, with the consequent influence of expression and rearrangement of these genomic sites in pancreatic cancer. Overall, these data suggest a potential functional and biochemical regulatory network connecting p53 and nuclear architecture.
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Affiliation(s)
- Emanuele Panatta
- grid.6530.00000 0001 2300 0941Department of Experimental Medicine, TOR, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Alessio Butera
- grid.9811.10000 0001 0658 7699Division of Systems Toxicology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Ivana Celardo
- grid.9811.10000 0001 0658 7699Division of in-Vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Marcel Leist
- grid.9811.10000 0001 0658 7699Division of in-Vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Gerry Melino
- grid.6530.00000 0001 2300 0941Department of Experimental Medicine, TOR, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Ivano Amelio
- grid.6530.00000 0001 2300 0941Department of Experimental Medicine, TOR, University of Rome Tor Vergata, 00133 Rome, Italy ,grid.9811.10000 0001 0658 7699Division of Systems Toxicology, Department of Biology, University of Konstanz, Konstanz, Germany
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16
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Fischer M, Schade AE, Branigan TB, Müller GA, DeCaprio JA. Coordinating gene expression during the cell cycle. Trends Biochem Sci 2022; 47:1009-1022. [PMID: 35835684 DOI: 10.1016/j.tibs.2022.06.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/08/2022] [Accepted: 06/14/2022] [Indexed: 02/08/2023]
Abstract
Cell cycle-dependent gene transcription is tightly controlled by the retinoblastoma (RB):E2F and DREAM complexes, which repress all cell cycle genes during quiescence. Cyclin-dependent kinase (CDK) phosphorylation of RB and DREAM allows for the expression of two gene sets. The first set of genes, with peak expression in G1/S, is activated by E2F transcription factors (TFs) and is required for DNA synthesis. The second set, with maximum expression during G2/M, is required for mitosis and is coordinated by the MuvB complex, together with B-MYB and Forkhead box M1 (FOXM1). In this review, we summarize the key findings that established the distinct control mechanisms regulating G1/S and G2/M gene expression in mammals and discuss recent advances in the understanding of the temporal control of these genes.
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Affiliation(s)
- Martin Fischer
- Computational Biology Group, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), 07745, Jena, Germany.
| | - Amy E Schade
- Genetics Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Timothy B Branigan
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Gerd A Müller
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - James A DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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17
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Synthesizing genome regulation data with vote-counting. Trends Genet 2022; 38:1208-1216. [PMID: 35817619 DOI: 10.1016/j.tig.2022.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/31/2022] [Accepted: 06/16/2022] [Indexed: 01/24/2023]
Abstract
The increasing availability of high-throughput datasets allows amalgamating research information across a large body of genome regulation studies. Given the recent success of meta-analyses on transcriptional regulators, epigenetic marks, and enhancer:gene associations, we expect that such surveys will continue to provide novel and reproducible insights. However, meta-analyses are severely hampered by the diversity of available data, concurring protocols, an eclectic amount of bioinformatics tools, and myriads of conceivable parameter combinations. Such factors can easily bar life scientists from synthesizing omics data and substantially curb their interpretability. Despite statistical challenges of the method, we would like to emphasize the advantages of joining data from different sources through vote-counting and showcase examples that achieve a simple but highly intuitive data integration.
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18
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Heijkants RC, Teunisse AFAS, de Jong D, Glinkina K, Mei H, Kielbasa SM, Szuhai K, Jochemsen AG. MDMX Regulates Transcriptional Activity of p53 and FOXO Proteins to Stimulate Proliferation of Melanoma Cells. Cancers (Basel) 2022; 14:cancers14184482. [PMID: 36139642 PMCID: PMC9496676 DOI: 10.3390/cancers14184482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/25/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary We have investigated the transcriptional changes occurring in uveal and cutaneous melanoma cell lines upon depletion of MDMX (aka:MDM4). Computational analyses of the mRNAs/genes affected upon MDMX depletion determined that many were containing a p53-bindingsite, but even more contained a FOX recognition site(s). Since connections between MDM2 and FOXO1 had already been published, we investigated whether indeed a subset of the MDMX-regulated genes are dependent on FOXO1/FOXO3 expression. Indeed, a number of such target genes, i.e., PIK3IP1, MXD4 and ZMAT3, were found to be FOXO target genes in our cell models. Some of these genes were recently identified as indirect p53-target genes, and their expression was found to be regulated by RFX7 transcription factor, which was found activated upon pharmacological activation of p53, e.g., by Nutlin-3. However, a clear involvement of RFX7 in our model could not be established, but an interplay between FOXO and RFX7 factors seems evident. Abstract The tumor suppressor protein p53 has an important role in cell-fate determination. In cancer cells, the activity of p53 is frequently repressed by high levels of MDMX and/or MDM2. MDM2 is a ubiquitin ligase whose activity results in ubiquitin- and proteasome-dependent p53 degradation, while MDMX inhibits p53-activated transcription by shielding the p53 transactivation domain. Interestingly, the oncogenic functions of MDMX appear to be more wide-spread than inhibition of p53. The present study aimed to elucidate the MDMX-controlled transcriptome. Therefore, we depleted MDMX with four distinct shRNAs from a high MDMX expressing uveal melanoma cell line and determined the effect on the transcriptome by RNAseq. Biological function analyses indicate the inhibition of the cell cycle regulatory genes and stimulation of cell death activating genes upon MDMX depletion. Although the inhibition of p53 activity clearly contributes to the transcription regulation controlled by MDMX, it appeared that the transcriptional regulation of multiple genes did not only rely on p53 expression. Analysis of gene regulatory networks indicated a role for Forkhead box (FOX) transcription factors. Depletion of FOXO proteins partly prevented the transcriptional changes upon MDMX depletion. Furthermore, depletion of FOXO proteins relatively diminished the growth inhibition upon MDMX knockdown, although the knockdown of the FOXO transcription factors also reduces cell growth. In conclusion, the p53-independent oncogenic functions of MDMX could be partially explained by its regulation of FOXO activity.
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Affiliation(s)
- Renier C. Heijkants
- Department of Cell and Chemical Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Amina F. A. S. Teunisse
- Department of Cell and Chemical Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Danielle de Jong
- Department of Cell and Chemical Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Kseniya Glinkina
- Department of Cell and Chemical Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Szymon M. Kielbasa
- Sequencing Analysis Support Core, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
- Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Karoly Szuhai
- Department of Cell and Chemical Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Aart G. Jochemsen
- Department of Cell and Chemical Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
- Correspondence:
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