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Abstract
p53 plays a key role in regulating DNA damage response by suppressing cell cycle progression or inducing apoptosis depending on extent of DNA damage. However, it is not clear why mild genotoxic stress favors growth arrest, whereas excessive lesions signal cells to die. Here we showed that TAp73, a p53 homologue thought to have a similar function as p53, restrains the transcriptional activity of p53 and prevents excessive activation of its downstream targets upon low levels of DNA damage, which results in cell cycle arrest. Extensive DNA damage triggers TAp73 depletion through ubiquitin/proteasome-mediated degradation of E2F1, leading to enhanced transcriptional activation by p53 and subsequent induction of apoptosis. These findings provide novel insights into the regulation of p53 function and suggest that TAp73 keeps p53 activity in check in regulating cell fate decisions upon genotoxic stress.
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Tebaldi T, Zaccara S, Alessandrini F, Bisio A, Ciribilli Y, Inga A. Whole-genome cartography of p53 response elements ranked on transactivation potential. BMC Genomics 2015; 16:464. [PMID: 26081755 PMCID: PMC4470028 DOI: 10.1186/s12864-015-1643-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 05/20/2015] [Indexed: 11/18/2022] Open
Abstract
Background Many recent studies using ChIP-seq approaches cross-referenced to trascriptome data and also to potentially unbiased in vitro DNA binding selection experiments are detailing with increasing precision the p53-directed gene regulatory network that, nevertheless, is still expanding. However, most experiments have been conducted in established cell lines subjected to specific p53-inducing stimuli, both factors potentially biasing the results. Results We developed p53retriever, a pattern search algorithm that maps p53 response elements (REs) and ranks them according to predicted transactivation potentials in five classes. Besides canonical, full site REs, we developed specific pattern searches for non-canonical half sites and 3/4 sites and show that they can mediate p53-dependent responsiveness of associated coding sequences. Using ENCODE data, we also mapped p53 REs in about 44,000 distant enhancers and identified a 16-fold enrichment for high activity REs within those sites in the comparison with genomic regions near transcriptional start sites (TSS). Predictions from our pattern search were cross-referenced to ChIP-seq, ChIP-exo, expression, and various literature data sources. Based on the mapping of predicted functional REs near TSS, we examined expression changes of thirteen genes as a function of different p53-inducing conditions, providing further evidence for PDE2A, GAS6, E2F7, APOBEC3H, KCTD1, TRIM32, DICER, HRAS, KITLG and TGFA p53-dependent regulation, while MAP2K3, DNAJA1 and potentially YAP1 were identified as new direct p53 target genes. Conclusions We provide a comprehensive annotation of canonical and non-canonical p53 REs in the human genome, ranked on predicted transactivation potential. We also establish or corroborate direct p53 transcriptional control of thirteen genes. The entire list of identified and functionally classified p53 REs near all UCSC-annotated genes and within ENCODE mapped enhancer elements is provided. Our approach is distinct from, and complementary to, existing methods designed to identify p53 response elements. p53retriever is available as an R package at: http://tomateba.github.io/p53retriever. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1643-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Toma Tebaldi
- Centre for Integrative Biology (CIBIO), University of Trento, via delle Regole 101, 38123, Mattarello, TN, Italy.
| | - Sara Zaccara
- Centre for Integrative Biology (CIBIO), University of Trento, via delle Regole 101, 38123, Mattarello, TN, Italy.
| | - Federica Alessandrini
- Centre for Integrative Biology (CIBIO), University of Trento, via delle Regole 101, 38123, Mattarello, TN, Italy.
| | - Alessandra Bisio
- Centre for Integrative Biology (CIBIO), University of Trento, via delle Regole 101, 38123, Mattarello, TN, Italy.
| | - Yari Ciribilli
- Centre for Integrative Biology (CIBIO), University of Trento, via delle Regole 101, 38123, Mattarello, TN, Italy.
| | - Alberto Inga
- Centre for Integrative Biology (CIBIO), University of Trento, via delle Regole 101, 38123, Mattarello, TN, Italy.
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53
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Kumazawa T, Nishimura K, Katagiri N, Hashimoto S, Hayashi Y, Kimura K. Gradual reduction in rRNA transcription triggers p53 acetylation and apoptosis via MYBBP1A. Sci Rep 2015; 5:10854. [PMID: 26044764 PMCID: PMC4456663 DOI: 10.1038/srep10854] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 05/05/2015] [Indexed: 12/19/2022] Open
Abstract
The nucleolus, whose primary function is ribosome biogenesis, plays an essential role in p53 activation. Ribosome biogenesis is inhibited in response to cellular stress and several nucleolar proteins translocate from the nucleolus to the nucleoplasm, where they activate p53. In this study, we analysed precisely how impaired ribosome biogenesis regulates the activation of p53 by depleting nucleolar factors involved in rRNA transcription or rRNA processing. Nucleolar RNA content decreased when rRNA transcription was inhibited. In parallel with the reduced levels of nucleolar RNA content, the nucleolar protein Myb-binding protein 1 A (MYBBP1A) translocated to the nucleoplasm and increased p53 acetylation. The acetylated p53 enhanced p21 and BAX expression and induced apoptosis. In contrast, when rRNA processing was inhibited, MYBBP1A remained in the nucleolus and nonacetylated p53 accumulated, causing cell cycle arrest at the G1 phase by inducing p21 but not BAX. We propose that the nucleolus functions as a stress sensor to modulate p53 protein levels and its acetylation status, determining cell fate between cell cycle arrest and apoptosis by regulating MYBBP1A translocation.
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Affiliation(s)
- Takuya Kumazawa
- 1] Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennnoudai, Tsukuba 305-8577, Japan [2] First Department of Internal Medicine, Nara Medical University, 840 Shijo-cho Kashihara, Nara 634-8522, Japan
| | - Kazuho Nishimura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennnoudai, Tsukuba 305-8577, Japan
| | - Naohiro Katagiri
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennnoudai, Tsukuba 305-8577, Japan
| | - Sayaka Hashimoto
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennnoudai, Tsukuba 305-8577, Japan
| | - Yuki Hayashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennnoudai, Tsukuba 305-8577, Japan
| | - Keiji Kimura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennnoudai, Tsukuba 305-8577, Japan
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54
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Speidel D. The role of DNA damage responses in p53 biology. Arch Toxicol 2015; 89:501-17. [PMID: 25618545 DOI: 10.1007/s00204-015-1459-z] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 01/08/2015] [Indexed: 12/16/2022]
Abstract
The tumour suppressor p53 is a central player in cellular DNA damage responses. P53 is upregulated and activated by genotoxic stress and induces a transcriptional programme with effectors promoting apoptosis, cell cycle arrest, senescence and DNA repair. For the best part of the last three decades, these DNA damage-related programmes triggered by p53 were unequivocally regarded as the major if not sole mechanism by which p53 exerts its tumour suppressor function. However, this interpretation has been challenged by a number of recent in vivo studies, demonstrating that mice which are defective in inducing p53-dependent apoptosis, cell cycle arrest and senescence suppress thymic lymphoma as well as wild-type p53 expressing animals. Consequently, the importance of DNA damage responses for p53-mediated tumour suppression has been questioned. In this review, I summarize current knowledge on p53-controlled DNA damage responses and argue that these activities, while their role has certainly changed, remain an important feature of p53 biology with relevance for cancer therapy and tumour suppression.
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Affiliation(s)
- Daniel Speidel
- Children's Medical Research Institute, 214 Hawkesbury Road, Westmead, NSW, 2145, Australia,
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55
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Singh SK, Chen NM, Hessmann E, Siveke J, Lahmann M, Singh G, Voelker N, Vogt S, Esposito I, Schmidt A, Brendel C, Stiewe T, Gaedcke J, Mernberger M, Crawford HC, Bamlet WR, Zhang JS, Li XK, Smyrk TC, Billadeau DD, Hebrok M, Neesse A, Koenig A, Ellenrieder V. Antithetical NFATc1-Sox2 and p53-miR200 signaling networks govern pancreatic cancer cell plasticity. EMBO J 2015; 34:517-30. [PMID: 25586376 DOI: 10.15252/embj.201489574] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In adaptation to oncogenic signals, pancreatic ductal adenocarcinoma (PDAC) cells undergo epithelial-mesenchymal transition (EMT), a process combining tumor cell dedifferentiation with acquisition of stemness features. However, the mechanisms linking oncogene-induced signaling pathways with EMT and stemness remain largely elusive. Here, we uncover the inflammation-induced transcription factor NFATc1 as a central regulator of pancreatic cancer cell plasticity. In particular, we show that NFATc1 drives EMT reprogramming and maintains pancreatic cancer cells in a stem cell-like state through Sox2-dependent transcription of EMT and stemness factors. Intriguingly, NFATc1-Sox2 complex-mediated PDAC dedifferentiation and progression is opposed by antithetical p53-miR200c signaling, and inactivation of the tumor suppressor pathway is essential for tumor dedifferentiation and dissemination both in genetically engineered mouse models (GEMM) and human PDAC. Based on these findings, we propose the existence of a hierarchical signaling network regulating PDAC cell plasticity and suggest that the molecular decision between epithelial cell preservation and conversion into a dedifferentiated cancer stem cell-like phenotype depends on opposing levels of p53 and NFATc1 signaling activities.
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Affiliation(s)
- Shiv K Singh
- Signaling and Transcription Laboratory, Department of Gastroenterology, Philipps University, Marburg, Germany
| | - Nai-Ming Chen
- Department of Gastroenterology II, University Medical Center Goettingen, Goettingen, Germany
| | - Elisabeth Hessmann
- Department of Gastroenterology II, University Medical Center Goettingen, Goettingen, Germany
| | - Jens Siveke
- II. Medizinische Klinik, Klinikum rechts der Isar, Technische Universität, Munich, Germany
| | - Marlen Lahmann
- Institute for Molecular Tumor Biology, Philipps University, Marburg, Germany
| | - Garima Singh
- Signaling and Transcription Laboratory, Department of Gastroenterology, Philipps University, Marburg, Germany
| | - Nadine Voelker
- Signaling and Transcription Laboratory, Department of Gastroenterology, Philipps University, Marburg, Germany
| | - Sophia Vogt
- Signaling and Transcription Laboratory, Department of Gastroenterology, Philipps University, Marburg, Germany
| | - Irene Esposito
- Institute of Pathology, Helmholtz Zentrum, Munich, Germany
| | - Ansgar Schmidt
- Institute of Pathology, Philipps University, Marburg, Germany
| | - Cornelia Brendel
- Department of Hematology and Oncology, Philipps University, Marburg, Germany
| | - Thorsten Stiewe
- Institute for Molecular Tumor Biology, Philipps University, Marburg, Germany
| | - Jochen Gaedcke
- Department of Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Marco Mernberger
- Institute for Molecular Tumor Biology, Philipps University, Marburg, Germany
| | - Howard C Crawford
- Department of Cancer Biology, Mayo Clinic Florida, Jacksonville, FL, USA
| | - William R Bamlet
- Division of Biostatistics, College of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Jin-San Zhang
- Division of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN, USA School of Pharmaceutical Sciences and Key Laboratory of Biotechnology and Pharmaceutical Engineering, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiao-Kun Li
- School of Pharmaceutical Sciences and Key Laboratory of Biotechnology and Pharmaceutical Engineering, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Thomas C Smyrk
- Division of Anatomic Pathology, Mayo Clinic, Rochester, MN, USA
| | - Daniel D Billadeau
- Division of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN, USA
| | | | - Albrecht Neesse
- Department of Gastroenterology II, University Medical Center Goettingen, Goettingen, Germany
| | - Alexander Koenig
- Department of Gastroenterology II, University Medical Center Goettingen, Goettingen, Germany Division of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Volker Ellenrieder
- Department of Gastroenterology II, University Medical Center Goettingen, Goettingen, Germany
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56
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Monti P, Ciribilli Y, Bisio A, Foggetti G, Raimondi I, Campomenosi P, Menichini P, Fronza G, Inga A. ∆N-P63α and TA-P63α exhibit intrinsic differences in transactivation specificities that depend on distinct features of DNA target sites. Oncotarget 2015; 5:2116-30. [PMID: 24926492 PMCID: PMC4039150 DOI: 10.18632/oncotarget.1845] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
TP63 is a member of the TP53 gene family that encodes for up to ten different TA and ΔN isoforms through alternative promoter usage and alternative splicing. Besides being a master regulator of gene expression for squamous epithelial proliferation, differentiation and maintenance, P63, through differential expression of its isoforms, plays important roles in tumorigenesis. All P63 isoforms share an immunoglobulin-like folded DNA binding domain responsible for binding to sequence-specific response elements (REs), whose overall consensus sequence is similar to that of the canonical p53 RE. Using a defined assay in yeast, where P63 isoforms and RE sequences are the only variables, and gene expression assays in human cell lines, we demonstrated that human TA- and ΔN-P63α proteins exhibited differences in transactivation specificity not observed with the corresponding P73 or P53 protein isoforms. These differences 1) were dependent on specific features of the RE sequence, 2) could be related to intrinsic differences in their oligomeric state and cooperative DNA binding, and 3) appeared to be conserved in evolution. Since genotoxic stress can change relative ratio of TA- and ΔN-P63α protein levels, the different transactivation specificity of each P63 isoform could potentially influence cellular responses to specific stresses.
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57
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Abstract
Discoveries in cytogenetics, molecular biology, and genomics have revealed that genome change is an active cell-mediated physiological process. This is distinctly at variance with the pre-DNA assumption that genetic changes arise accidentally and sporadically. The discovery that DNA changes arise as the result of regulated cell biochemistry means that the genome is best modelled as a read-write (RW) data storage system rather than a read-only memory (ROM). The evidence behind this change in thinking and a consideration of some of its implications are the subjects of this article. Specific points include the following: cells protect themselves from accidental genome change with proofreading and DNA damage repair systems; localized point mutations result from the action of specialized trans-lesion mutator DNA polymerases; cells can join broken chromosomes and generate genome rearrangements by non-homologous end-joining (NHEJ) processes in specialized subnuclear repair centres; cells have a broad variety of natural genetic engineering (NGE) functions for transporting, diversifying and reorganizing DNA sequences in ways that generate many classes of genomic novelties; natural genetic engineering functions are regulated and subject to activation by a range of challenging life history events; cells can target the action of natural genetic engineering functions to particular genome locations by a range of well-established molecular interactions, including protein binding with regulatory factors and linkage to transcription; and genome changes in cancer can usefully be considered as consequences of the loss of homeostatic control over natural genetic engineering functions.
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Affiliation(s)
- James A Shapiro
- Department of Biochemistry and Molecular Biology, University of Chicago, GCISW123B, 979 E. 57th Street, Chicago, IL 60637, USA
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58
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Abstract
p53 is a crucial tumour suppressor that responds to diverse stress signals by orchestrating specific cellular responses, including transient cell cycle arrest, cellular senescence and apoptosis, which are all processes associated with tumour suppression. However, recent studies have challenged the relative importance of these canonical cellular responses for p53-mediated tumour suppression and have highlighted roles for p53 in modulating other cellular processes, including metabolism, stem cell maintenance, invasion and metastasis, as well as communication within the tumour microenvironment. In this Opinion article, we discuss the roles of classical p53 functions, as well as emerging p53-regulated processes, in tumour suppression.
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Affiliation(s)
- Kathryn T Bieging
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, CCSR-South, Room 1255, 269 Campus Drive, Stanford, California 94305, USA
| | - Stephano Spano Mello
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, CCSR-South, Room 1255, 269 Campus Drive, Stanford, California 94305, USA
| | - Laura D Attardi
- 1] Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, CCSR-South, Room 1255, 269 Campus Drive, Stanford, California 94305, USA. [2] Department of Genetics, Stanford University School of Medicine, CCSR-South, Room 1255, 269 Campus Drive, Stanford, California 94305, USA
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59
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Khoo KH, Hoe KK, Verma CS, Lane DP. Drugging the p53 pathway: understanding the route to clinical efficacy. Nat Rev Drug Discov 2014; 13:217-36. [PMID: 24577402 DOI: 10.1038/nrd4236] [Citation(s) in RCA: 555] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The tumour suppressor p53 is the most frequently mutated gene in human cancer, with more than half of all human tumours carrying mutations in this particular gene. Intense efforts to develop drugs that could activate or restore the p53 pathway have now reached clinical trials. The first clinical results with inhibitors of MDM2, a negative regulator of p53, have shown efficacy but hint at on-target toxicities. Here, we describe the current state of the development of p53 pathway modulators and new pathway targets that have emerged. The challenge of targeting protein-protein interactions and a fragile mutant transcription factor has stimulated many exciting new approaches to drug discovery.
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Affiliation(s)
| | - Khoo Kian Hoe
- p53 Laboratory (p53Lab), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, #06-06, Immunos, 138648 Singapore
| | - Chandra S Verma
- 1] Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street #07-01, Matrix, 138671 Singapore. [2] School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore. [3] Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543 Singapore
| | - David P Lane
- p53 Laboratory (p53Lab), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, #06-06, Immunos, 138648 Singapore
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60
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Bisio A, Ciribilli Y, Fronza G, Inga A, Monti P. TP53 Mutants in the Tower of Babel of Cancer Progression. Hum Mutat 2014; 35:689-701. [DOI: 10.1002/humu.22514] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 01/06/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Alessandra Bisio
- Laboratory of Transcriptional Networks; Centre for Integrative Biology (CIBIO); University of Trento; Trento Italy
| | - Yari Ciribilli
- Laboratory of Transcriptional Networks; Centre for Integrative Biology (CIBIO); University of Trento; Trento Italy
| | - Gilberto Fronza
- Mutagenesis Unit; IRCSS Azienda Ospedaliera Universitaria San Martino-IST-Istituto Nazionale per la Ricerca sul Cancro; Genoa Italy
| | - Alberto Inga
- Laboratory of Transcriptional Networks; Centre for Integrative Biology (CIBIO); University of Trento; Trento Italy
| | - Paola Monti
- Mutagenesis Unit; IRCSS Azienda Ospedaliera Universitaria San Martino-IST-Istituto Nazionale per la Ricerca sul Cancro; Genoa Italy
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61
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Trusina A. Stress induced telomere shortening: longer life with less mutations? BMC SYSTEMS BIOLOGY 2014; 8:27. [PMID: 24580844 PMCID: PMC4015310 DOI: 10.1186/1752-0509-8-27] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Accepted: 02/17/2014] [Indexed: 01/15/2023]
Abstract
Background Mutations accumulate as a result of DNA damage and imperfect DNA repair machinery. In higher eukaryotes the accumulation and spread of mutations is limited in two primary ways: through p53-mediated programmed cell death and cellular senescence mediated by telomeres. Telomeres shorten at every cell division and cell stops dividing once the shortest telomere reaches a critical length. It has been shown that the rate of telomere attrition is accelerated when cells are exposed to DNA damaging agents. However the implications of this mechanism are not fully understood. Results With the help of in silico model we investigate the effect of genotoxic stress on telomere attrition and apoptosis in a population of non-identical replicating cells. When comparing the populations of cells with constant vs. stress-induced rate of telomere shortening we find that stress induced telomere shortening (SITS) increases longevity while reducing mutation rate. Interestingly, however, the effect takes place only when genotoxic stresses (e.g. reactive oxygen species due to metabolic activity) are distributed non-equally among cells. Conclusions Our results for the first time show how non-equal distribution of metabolic load (and associated genotoxic stresses) combined with stress induced telomere shortening can delay aging and minimize mutations.
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Affiliation(s)
- Ala Trusina
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK 2100, Copenhagen, Denmark.
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62
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Abstract
The mechanisms by which p53 suppresses tumor growth remain ill defined. In this issue of Cell Reports, Timofeev et al. (2013) and Valente et al. (2013) reveal context-dependent contributions of p53-dependent apoptosis to its tumor-suppressive function.
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Affiliation(s)
- Hestia Mellert
- Howard Hughes Medical Institute and Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
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63
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Cui F, Zhurkin VB. Rotational positioning of nucleosomes facilitates selective binding of p53 to response elements associated with cell cycle arrest. Nucleic Acids Res 2013; 42:836-47. [PMID: 24153113 PMCID: PMC3902933 DOI: 10.1093/nar/gkt943] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The tumor suppressor protein p53 exhibits high affinity to the response elements regulating cell cycle arrest genes (CCA-sites), but relatively low affinity to the sites associated with apoptosis (Apo-sites). This in vivo tendency cannot be explained solely by the p53-DNA binding constants measured in vitro. Since p53 can bind nucleosomal DNA, we sought to understand if the two groups of p53 sites differ in their accessibility when embedded in nucleosomes. To this aim, we analyzed the sequence-dependent bending anisotropy of human genomic DNA containing p53 sites. For the 20 CCA-sites, we calculated rotational positioning patterns predicting that most of the sites are exposed on the nucleosomal surface. This is consistent with experimentally observed positioning of human nucleosomes. Remarkably, the sequence-dependent DNA anisotropy of both the p53 sites and flanking DNA work in concert producing strong positioning signals. By contrast, both the predicted and observed rotational settings of the 38 Apo-sites in nucleosomes suggest that many of these sites are buried inside, thus preventing immediate p53 recognition and delaying gene induction. The distinct chromatin organization of the CCA response elements appears to be one of the key factors facilitating p53-DNA binding and subsequent activation of genes associated with cell cycle arrest.
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Affiliation(s)
- Feng Cui
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, 85 Lomb Memorial Drive Rochester, NY 14623, USA and Laboratory of Cell Biology, National Cancer Institute, NIH Bg. 37, Room 3035A, Convent Dr., Bethesda, MD 20892, USA
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64
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Pagano B, Jama A, Martinez P, Akanho E, Bui TTT, Drake AF, Fraternali F, Nikolova PV. Structure and stability insights into tumour suppressor p53 evolutionary related proteins. PLoS One 2013; 8:e76014. [PMID: 24124530 PMCID: PMC3790848 DOI: 10.1371/journal.pone.0076014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/19/2013] [Indexed: 01/06/2023] Open
Abstract
The p53 family of genes and their protein products, namely, p53, p63 and p73, have over one billion years of evolutionary history. Advances in computational biology and genomics are enabling studies of the complexities of the molecular evolution of p53 protein family to decipher the underpinnings of key biological conditions spanning from cancer through to various metabolic and developmental disorders and facilitate the design of personalised medicines. However, a complete understanding of the inherent nature of the thermodynamic and structural stability of the p53 protein family is still lacking. This is due, to a degree, to the lack of comprehensive structural information for a large number of homologous proteins and to an incomplete knowledge of the intrinsic factors responsible for their stability and how these might influence function. Here we investigate the thermal stability, secondary structure and folding properties of the DNA-binding domains (DBDs) of a range of proteins from the p53 family using biophysical methods. While the N- and the C-terminal domains of the p53 family show sequence diversity and are normally targets for post-translational modifications and alternative splicing, the central DBD is highly conserved. Together with data obtained from Molecular Dynamics simulations in solution and with structure based homology modelling, our results provide further insights into the molecular properties of evolutionary related p53 proteins. We identify some marked structural differences within the p53 family, which could account for the divergence in biological functions as well as the subtleties manifested in the oligomerization properties of this family.
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Affiliation(s)
- Bruno Pagano
- King’s College London, School of Biomedical Sciences, Department of Biochemistry & Randall Division of Cell and Molecular Biophysics, New Hunt’s House, London, United Kingdom
- Department of Pharmacy, University of Naples “Federico II”, Napoli, Italy
| | - Abdullah Jama
- Institute for Pharmaceutical Science, London, United Kingdom
| | - Pierre Martinez
- King’s College London, School of Biomedical Sciences, Department of Biochemistry & Randall Division of Cell and Molecular Biophysics, New Hunt’s House, London, United Kingdom
| | - Ester Akanho
- Institute for Pharmaceutical Science, London, United Kingdom
| | - Tam T. T. Bui
- Institute for Pharmaceutical Science, London, United Kingdom
| | - Alex F. Drake
- Institute for Pharmaceutical Science, London, United Kingdom
| | - Franca Fraternali
- King’s College London, School of Biomedical Sciences, Department of Biochemistry & Randall Division of Cell and Molecular Biophysics, New Hunt’s House, London, United Kingdom
- * E-mail: (PN), (FF)
| | - Penka V. Nikolova
- Institute for Pharmaceutical Science, London, United Kingdom
- * E-mail: (PN), (FF)
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65
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Schlereth K, Heyl C, Krampitz AM, Mernberger M, Finkernagel F, Scharfe M, Jarek M, Leich E, Rosenwald A, Stiewe T. Characterization of the p53 cistrome--DNA binding cooperativity dissects p53's tumor suppressor functions. PLoS Genet 2013; 9:e1003726. [PMID: 23966881 PMCID: PMC3744428 DOI: 10.1371/journal.pgen.1003726] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 07/01/2013] [Indexed: 01/07/2023] Open
Abstract
p53 protects us from cancer by transcriptionally regulating tumor suppressive programs designed to either prevent the development or clonal expansion of malignant cells. How p53 selects target genes in the genome in a context- and tissue-specific manner remains largely obscure. There is growing evidence that the ability of p53 to bind DNA in a cooperative manner prominently influences target gene selection with activation of the apoptosis program being completely dependent on DNA binding cooperativity. Here, we used ChIP-seq to comprehensively profile the cistrome of p53 mutants with reduced or increased cooperativity. The analysis highlighted a particular relevance of cooperativity for extending the p53 cistrome to non-canonical binding sequences characterized by deletions, spacer insertions and base mismatches. Furthermore, it revealed a striking functional separation of the cistrome on the basis of cooperativity; with low cooperativity genes being significantly enriched for cell cycle and high cooperativity genes for apoptotic functions. Importantly, expression of high but not low cooperativity genes was correlated with superior survival in breast cancer patients. Interestingly, in contrast to most p53-activated genes, p53-repressed genes did not commonly contain p53 binding elements. Nevertheless, both the degree of gene activation and repression were cooperativity-dependent, suggesting that p53-mediated gene repression is largely indirect and mediated by cooperativity-dependently transactivated gene products such as CDKN1A, E2F7 and non-coding RNAs. Since both activation of apoptosis genes with non-canonical response elements and repression of pro-survival genes are crucial for p53's apoptotic activity, the cistrome analysis comprehensively explains why p53-induced apoptosis, but not cell cycle arrest, strongly depends on the intermolecular cooperation of p53 molecules as a possible safeguard mechanism protecting from accidental cell killing. The tumor suppressor gene p53 counteracts tumor growth by activating genes that prevent cell proliferation or induce cell death. How p53 selects genes in the genome to direct cell fate specifically into one or the other direction remains unclear. We show that the ability of p53 molecules to interact and thereby cooperate, influences which genes in the genome p53 is regulating. In the absence of cooperation, p53 only binds and regulates a limited ‘default’ set of genes that is proficient to stop cell proliferation but insufficient to induce cell death. Cooperation increases p53's DNA binding and enables context-dependent activation of apoptosis genes and repression of pro-survival genes which together triggers cell death. As the concerted effort of p53 molecules is needed, the threshold for cell killing is raised possibly to protect us from accidental cell loss. Thus, by shaping the genomic binding pattern, p53 cooperation fine-tunes the gene activity pattern to steer cell fate into the most appropriate, context-dependent direction. The genome-wide binding patterns of cooperating and non-cooperating p53 proteins generated in this study provide a comprehensive list of p53 binding sites as a resource for the scientific community to further explore mechanisms of tumor suppression by p53.
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Affiliation(s)
| | - Charlotte Heyl
- Molecular Oncology, Philipps-University, Marburg, Germany
| | | | | | - Florian Finkernagel
- Institute of Molecular Biology and Tumor Research, Philipps-University, Marburg, Germany
| | - Maren Scharfe
- Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Michael Jarek
- Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ellen Leich
- Institute of Pathology, University of Würzburg, Würzburg, Germany
| | | | - Thorsten Stiewe
- Molecular Oncology, Philipps-University, Marburg, Germany
- * E-mail:
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66
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Ciribilli Y, Monti P, Bisio A, Nguyen HT, Ethayathulla AS, Ramos A, Foggetti G, Menichini P, Menendez D, Resnick MA, Viadiu H, Fronza G, Inga A. Transactivation specificity is conserved among p53 family proteins and depends on a response element sequence code. Nucleic Acids Res 2013; 41:8637-53. [PMID: 23892287 PMCID: PMC3794606 DOI: 10.1093/nar/gkt657] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Structural and biochemical studies have demonstrated that p73, p63 and p53 recognize DNA with identical amino acids and similar binding affinity. Here, measuring transactivation activity for a large number of response elements (REs) in yeast and human cell lines, we show that p53 family proteins also have overlapping transactivation profiles. We identified mutations at conserved amino acids of loops L1 and L3 in the DNA-binding domain that tune the transactivation potential nearly equally in p73, p63 and p53. For example, the mutant S139F in p73 has higher transactivation potential towards selected REs, enhanced DNA-binding cooperativity in vitro and a flexible loop L1 as seen in the crystal structure of the protein–DNA complex. By studying, how variations in the RE sequence affect transactivation specificity, we discovered a RE-transactivation code that predicts enhanced transactivation; this correlation is stronger for promoters of genes associated with apoptosis.
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Affiliation(s)
- Yari Ciribilli
- Laboratory of Transcriptional Networks, Centre for Integrative Biology (CIBIO), University of Trento, TN, 38060 Italy, Molecular Mutagenesis and DNA Repair Unit, IRCSS Azienda Ospedaliera Universitaria San Martino-IST-Istituto Nazionale per la Ricerca sul Cancro, Genoa 16132, Italy, Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, 92093, USA and Chromosome Stability Group, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, NIEHS, NIH, RTP, NC, 27709, USA
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67
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Abstract
Resting tumor cells represent a huge challenge during anticancer therapy due to their increased treatment resistance. TNF-related apoptosis-inducing ligand (TRAIL) is a putative future anticancer drug, currently in phases I and II clinical studies. We recently showed that TRAIL is able to target leukemia stem cell surrogates. Here, we tested the ability of TRAIL to target cell cycle-arrested tumor cells. Cell cycle arrest was induced in tumor cell lines and xenografted tumor cells in G0, G1 or G2 using cytotoxic drugs, phase-specific inhibitors or RNA interference against cyclinB and E. Biochemical or molecular arrest at any point of the cell cycle increased TRAIL-induced apoptosis. Accordingly, when cell cycle arrest was disabled by addition of caffeine, the antitumor activity of TRAIL was reduced. Most important for clinical translation, tumor cells from three children with B precursor or T cell acute lymphoblastic leukemia showed increased TRAIL-induced apoptosis upon knockdown of either cyclinB or cyclinE, arresting the cell cycle in G2 or G1, respectively. Taken together and in contrast to most conventional cytotoxic drugs, TRAIL exerts enhanced antitumor activity against cell cycle-arrested tumor cells. Therefore, TRAIL might represent an interesting drug to treat static-tumor disease, for example, during minimal residual disease.
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68
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Timofeev O, Schlereth K, Wanzel M, Braun A, Nieswandt B, Pagenstecher A, Rosenwald A, Elsässer HP, Stiewe T. p53 DNA binding cooperativity is essential for apoptosis and tumor suppression in vivo. Cell Rep 2013; 3:1512-25. [PMID: 23665223 DOI: 10.1016/j.celrep.2013.04.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/08/2013] [Accepted: 04/08/2013] [Indexed: 10/26/2022] Open
Abstract
Four molecules of the tumor suppressor p53 assemble to cooperatively bind proapoptotic target genes. The structural basis for cooperativity consists of interactions between adjacent DNA binding domains. Mutations at the interaction interface that compromise cooperativity were identified in cancer patients, suggesting a requirement of cooperativity for tumor suppression. We report on an analysis of cooperativity mutant p53E177R mice. Apoptotic functions of p53 triggered by DNA damage and oncogenes were abolished in these mice, whereas functions in cell-cycle control, senescence, metabolism, and antioxidant defense were retained and were sufficient to suppress development of spontaneous T cell lymphoma. Cooperativity mutant mice are nevertheless highly cancer prone and susceptible to different oncogene-induced tumors. Our data underscore the relevance of DNA binding cooperativity for p53-dependent apoptosis and tumor suppression and highlight cooperativity mutations as a class of p53 mutations that result in a selective loss of apoptotic functions due to an altered quaternary structure of the p53 tetramer.
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Affiliation(s)
- Oleg Timofeev
- Department of Molecular Oncology, University of Marburg, 35032 Marburg, Germany
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69
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Impact of the p53 status of tumor cells on extrinsic and intrinsic apoptosis signaling. Cell Commun Signal 2013; 11:27. [PMID: 23594441 PMCID: PMC3641951 DOI: 10.1186/1478-811x-11-27] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 04/03/2013] [Indexed: 12/19/2022] Open
Abstract
Background The p53 protein is the best studied target in human cancer. For decades, p53 has been believed to act mainly as a tumor suppressor and by transcriptional regulation. Only recently, the complex and diverse function of p53 has attracted more attention. Using several molecular approaches, we studied the impact of different p53 variants on extrinsic and intrinsic apoptosis signaling. Results We reproduced the previously published results within intrinsic apoptosis induction: while wild-type p53 promoted cell death, different p53 mutations reduced apoptosis sensitivity. The prediction of the impact of the p53 status on the extrinsic cell death induction was much more complex. The presence of p53 in tumor cell lines and primary xenograft tumor cells resulted in either augmented, unchanged or reduced cell death. The substitution of wild-type p53 by mutant p53 did not affect the extrinsic apoptosis inducing capacity. Conclusions In summary, we have identified a non-expected impact of p53 on extrinsic cell death induction. We suggest that the impact of the p53 status of tumor cells on extrinsic apoptosis signaling should be studied in detail especially in the context of therapeutic approaches that aim to restore p53 function to facilitate cell death via the extrinsic apoptosis pathway.
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70
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Human cytomegalovirus pUL29/28 and pUL38 repression of p53-regulated p21CIP1 and caspase 1 promoters during infection. J Virol 2012; 87:2463-74. [PMID: 23236067 DOI: 10.1128/jvi.01926-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
During infection by human cytomegalovirus (HCMV), the tumor suppressor protein p53, which promotes efficient viral gene expression, is stabilized. However, the expression of numerous p53-responsive cellular genes is not upregulated. The molecular mechanism used to manipulate the transcriptional activity of p53 during infection remains unclear. The HCMV proteins IE1, IE2, pUL44, and pUL84 likely contribute to the regulation of p53. In this study, we used a discovery-based approach to identify the protein targets of the HCMV protein pUL29/28 during infection. Previous studies have demonstrated that pUL29/28 regulates viral gene expression by interacting with the chromatin remodeling complex NuRD. Here, we observed that pUL29/28 also associates with p53, an additional deacetylase complex, and several HCMV proteins, including pUL38. We confirmed the interaction between p53 and pUL29/28 in both the presence and absence of infection. HCMV pUL29/28 with pUL38 altered the activity of the 53-regulatable p21CIP1 promoter. During infection, pUL29/28 and pUL38 contributed to the inhibition of p21CIP1 as well as caspase 1 expression. The expression of several other p53-regulating genes was not altered. Infection using a UL29-deficient virus resulted in increased p53 binding and histone H3 acetylation at the responsive promoters. Furthermore, expression of pUL29/28 and its interacting partner pUL38 contributed to an increase in the steady-state protein levels of p53. This study identified two additional HCMV proteins, pUL29/28 and pUL38, which participate in the complex regulation of p53 transcriptional activity during infection.
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71
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Oxidized DJ-1 inhibits p53 by sequestering p53 from promoters in a DNA-binding affinity-dependent manner. Mol Cell Biol 2012; 33:340-59. [PMID: 23149933 DOI: 10.1128/mcb.01350-12] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
DJ-1 is an oncogene and the causative gene for familial Parkinson's disease. Although the oxidative status of DJ-1 at cysteine 106 (C106) is thought to affect all of the activities of DJ-1 and excess oxidation leads to the onset of various diseases, the precise molecular mechanisms underlying the effects of oxidation of DJ-1 on protein-protein interactions of DJ-1 remain unclear. In this study, we found that DJ-1 bound to the DNA-binding region of p53 in a manner dependent on the oxidation of C106. Of the p53 target genes, the expression level and promoter activity of the DUSP1 gene, but not those of the p21 gene, were increased in H(2)O(2)-treated DJ-1(-/-) cells and were decreased in wild-type DJ-1- but not C106S DJ-1-transfected H1299 cells through sequestration of p53 from the DUSP1 promoter by DJ-1. DUSP1 downregulated by oxidized DJ-1 activated extracellular signal-regulated kinase (ERK) and decreased apoptosis. The DUSP1 and p21 promoters harbor nonconsensus and consensus p53 recognition sequences, respectively, which have low affinity and high affinity for p53. However, DJ-1 inhibited p21 promoter activity exhibited by p53 mutants harboring low DNA-binding affinity but not by wild-type p53. These results indicate that DJ-1 inhibits the expression of p53 target genes and depend on p53 DNA-binding affinity and oxidation of DJ-1 C106.
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72
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Yunlei Z, Zhe C, Yan L, Pengcheng W, Yanbo Z, Le S, Qianjin L. INMAP, a novel truncated version of POLR3B, represses AP-1 and p53 transcriptional activity. Mol Cell Biochem 2012; 374:81-9. [PMID: 23124897 DOI: 10.1007/s11010-012-1507-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 10/25/2012] [Indexed: 12/17/2022]
Abstract
INMAP was first identified as an interphase nucleus and mitotic apparatus-associated protein that plays essential roles in the formation of the spindle and cell-cycle progression. Here, we report that INMAP might be conserved from prokaryotes to humans, is a truncated version of the RNA polymerase III subunit B POLR3B, and is up-regulated in several human cancer cell lines including HeLa, Bel-7402, HepG2 and BGC-823. Deletion analysis revealed that the 209-290 amino-acid region is necessary for the punctate distribution of INMAP in the nucleus. Furthermore, over-expression of INMAP inhibited the transcriptional activities of p53 and AP-1 in a dose-dependent manner. These results suggest that INMAP may function through the p53 and AP-1 pathways, thus providing a possible link of its activity with tumourigenesis. Integrating our data and those in previous studies, it can be concluded that INMAP plays dual functional roles in the coordination of mitotic kinetics with gene expression as well as in cell-fate determination and proliferation.
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Affiliation(s)
- Zhou Yunlei
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, 100875, People's Republic of China
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73
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Abstract
Understanding how the tumor suppressor p53 induces cell cycle arrest or apoptosis is critical for developing chemotherapeutic strategies. We have generated targeted transgenic reporter mice with which we can study p53 activity at specific promoters, and propose a model in which p53 protein conformation is key to target gene selection.
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Affiliation(s)
- Amanda M Goh
- p53 Laboratory, Agency for Science, Technology and Research, Singapore
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74
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Li H, Qian W, Weng X, Wu Z, Li H, Zhuang Q, Feng B, Bian Y. Glucocorticoid receptor and sequential P53 activation by dexamethasone mediates apoptosis and cell cycle arrest of osteoblastic MC3T3-E1 cells. PLoS One 2012; 7:e37030. [PMID: 22719835 PMCID: PMC3375272 DOI: 10.1371/journal.pone.0037030] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 04/11/2012] [Indexed: 12/02/2022] Open
Abstract
Glucocorticoids play a pivotal role in the proliferation of osteoblasts, but the underlying mechanism has not been successfully elucidated. In this report, we have investigated the molecular mechanism which elucidates the inhibitory effects of dexamethasone on murine osteoblastic MC3T3-E1 cells. It was found that the inhibitory effects were largely attributed to apoptosis and G1 phase arrest. Both the cell cycle arrest and apoptosis were dependent on glucocorticoid receptor (GR), as they were abolished by GR blocker RU486 pre-treatment and GR interference. G1 phase arrest and apoptosis were accompanied with a p53-dependent up-regulation of p21 and pro-apoptotic genes NOXA and PUMA. We also proved that dexamethasone can’t induce apoptosis and cell cycle arrest when p53 was inhibited by p53 RNA interference. These data demonstrate that proliferation of MC3T3-E1 cell was significantly and directly inhibited by dexamethasone treatment via aberrant GR activation and subsequently P53 activation.
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Affiliation(s)
- Hui Li
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Wenwei Qian
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xisheng Weng
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- * E-mail:
| | - Zhihong Wu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Huihua Li
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Qianyu Zhuang
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Bin Feng
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yanyan Bian
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
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75
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Guan YQ, Zheng Z, Liang L, Li Z, Zhang L, Du J, Liu JM. The apoptosis of OVCAR-3 induced by TNF-α plus IFN-γ co-immobilized polylactic acid copolymers. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm31972a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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76
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Muscolini M, Montagni E, Palermo V, Di Agostino S, Gu W, Abdelmoula-Souissi S, Mazzoni C, Blandino G, Tuosto L. The cancer-associated K351N mutation affects the ubiquitination and the translocation to mitochondria of p53 protein. J Biol Chem 2011; 286:39693-702. [PMID: 21953469 PMCID: PMC3220532 DOI: 10.1074/jbc.m111.279539] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 09/27/2011] [Indexed: 12/17/2022] Open
Abstract
Stress-induced monoubiquitination of p53 is a crucial event for the nuclear-cytoplasm-mitochondria trafficking and transcription-independent pro-apoptotic functions of p53. Although an intact ubiquitination pathway and a functional nuclear export sequence are required for p53 nuclear export, the role of specific residues within this region in regulating both processes remains largely unknown. Here we characterize the mechanisms accounting for the nuclear accumulation of a new point mutation (Lys-351 to Asn) in the nuclear export sequence of p53 identified in a cisplatin-resistant ovarian carcinoma cell line (A2780 CIS). We found that K351N substitution abrogates the monoubiquitination of p53 induced by both Mdm2 and MSL2 E3-ligases. As a consequence, cells expressing p53 K351N mutant showed defects in cisplatin-induced translocation of p53 to mitochondria, Bax oligomerization, and mitochondrial membrane depolarization. These data identify K351N as a critical mutation of p53 that contributes to the development and maintenance of resistance to cisplatin.
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Affiliation(s)
- Michela Muscolini
- From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Biology and Biotechnology, Sapienza University, 00185-Rome, Italy
| | - Elisa Montagni
- From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Biology and Biotechnology, Sapienza University, 00185-Rome, Italy
| | - Vanessa Palermo
- From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Biology and Biotechnology, Sapienza University, 00185-Rome, Italy
| | - Silvia Di Agostino
- the Translational Oncogenomic Unit, Via Elio Chianesi, Istituto Regina Elena-IFO, 00144-Rome, Italy
| | - Wei Gu
- the Institute for Cancer Genetics and Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10027, and
| | | | - Cristina Mazzoni
- From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Biology and Biotechnology, Sapienza University, 00185-Rome, Italy
| | - Giovanni Blandino
- the Translational Oncogenomic Unit, Via Elio Chianesi, Istituto Regina Elena-IFO, 00144-Rome, Italy
| | - Loretta Tuosto
- From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Biology and Biotechnology, Sapienza University, 00185-Rome, Italy
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77
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Zhou Z, Sturgis EM, Liu Z, Wang LE, Wei Q, Li G. Genetic variants of a BH3-only pro-apoptotic gene, PUMA, and risk of HPV16-associated squamous cell carcinoma of the head and neck. Mol Carcinog 2011; 51 Suppl 1:E54-64. [PMID: 22086558 DOI: 10.1002/mc.21838] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 10/13/2011] [Accepted: 10/19/2011] [Indexed: 11/11/2022]
Abstract
P53 up-regulated modulator of apoptosis (PUMA) is a critical factor in the intrinsic apoptotic pathway. Through PUMA-dependent mechanisms, human papillomavirus 16 (HPV16) oncoprotein may affect apoptosis by E6-mediated p53 degradation. To examine whether the PUMA variants modify the association between HPV16 serology and risk of squamous cell carcinoma of the head and neck (SCCHN), we genotyped two polymorphisms in the PUMA promoter (rs3810294 and rs2032809) in 380 cases and 335 cancer-free controls of non-Hispanic Whites, who were frequency-matched by age (±5 yr), sex, smoking, and drinking status. We found that each individual polymorphism had only a modest impact on risk of SCCHN, particularly in oropharyngeal cancer for rs3810294 and non-oropharyngeal cancer for rs2032809. After we stratified the individuals by HPV16 serology, and used those with the corresponding common homozygous genotype and HPV16 seronegativity as the reference group, for each polymorphism we found that the risk of SCCHN associated with HPV16 seropositivity was higher among those with variant genotypes than those with the corresponding common homozygous genotype. Notably, this effect modification was particularly pronounced in several subgroups including never smokers, never drinkers, younger patients, and patients with oropharyngeal cancer. Furthermore, we also characterized the functional relevance of the two polymorphisms to explore the genotype-phenotype correlation. Our results suggested that the PUMA promoter polymorphisms may be a biomarker for risk of HPV16-associated SCCHN, particularly in never smokers, never drinkers, younger patients, and patients with oropharyngeal cancer. Larger studies are needed to validate our findings.
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Affiliation(s)
- Ziyuan Zhou
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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78
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Endogenous retrovirus drives hitherto unknown proapoptotic p63 isoforms in the male germ line of humans and great apes. Proc Natl Acad Sci U S A 2011; 108:3624-9. [PMID: 21300884 DOI: 10.1073/pnas.1016201108] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
TAp63, but not its homolog p53, eliminates oocytes that suffered DNA damage. An equivalent gene for guarding the male germ line is currently not known. Here we identify hitherto unknown human p63 transcripts with unique 5'-ends derived from incorporated exons upstream of the currently mapped TP63 gene. These unique p63 transcripts are highly and specifically expressed in testis. Their most upstream region corresponds to a LTR of the human endogenous retrovirus 9 (ERV9). The insertion of this LTR upstream of the TP63 locus occurred only recently in evolution and is unique to humans and great apes (Hominidae). A corresponding p63 protein is the sole p63 species in healthy human testis, and is strongly expressed in spermatogenic precursors but not in mature spermatozoa. In response to DNA damage, this human male germ-cell-encoded TAp63 protein (designated GTAp63) is activated by caspase cleavage near its carboxyterminal domain and induces apoptosis. Human testicular cancer tissues and cell lines largely lost p63 expression. However, pharmacological inhibition of histone deacetylases completely restores p63 expression in testicular cancer cells (>3,000-fold increase). Our data support a model whereby testis-specific GTAp63 protects the genomic integrity of the male germ line and acts as a tumor suppressor. In Hominidae, this guardian function was greatly enhanced by integration of an endogenous retrovirus upstream of the TP63 locus that occurred 15 million years ago. By providing increased germ-line stability, this event may have contributed to the evolution of hominids and enabled their long reproductive periods.
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79
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Abstract
Mutations in the TP53 gene are a feature of 50% of all reported cancer cases. In the other 50% of cases, the TP53 gene itself is not mutated but the p53 pathway is often partially inactivated. Cancer therapies that target specific mutant genes are proving to be highly active and trials assessing agents that exploit the p53 system are ongoing. Many trials are aimed at stratifying patients on the basis of TP53 status. In another approach, TP53 is delivered as a gene therapy; this is the only currently approved p53-based treatment. The p53 protein is overexpressed in many cancers and p53-based vaccines are undergoing trials. Processed cell-surface p53 is being exploited as a target for protein-drug conjugates, and small-molecule drugs that inhibit the activity of MDM2, the E3 ligase that regulates p53 levels, have been developed by several companies. The first MDM2 inhibitors are being trialed in both hematologic and solid malignancies. Finally, the first agent found to restore the active function of mutant TP53 has just entered the clinic. Here we discuss the basis of these trials and the future of p53-based therapy.
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80
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Schlereth K, Charles JP, Bretz AC, Stiewe T. Life or death: p53-induced apoptosis requires DNA binding cooperativity. Cell Cycle 2010; 9:4068-76. [PMID: 20948308 DOI: 10.4161/cc.9.20.13595] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The tumor suppressor p53 provides exquisite protection from cancer by balancing cell survival and death in response to stress. Sustained stress or irreparable damage trigger p53's killer functions to permanently eliminate genetically-altered cells as a potential source of cancer. To prevent the unnecessary loss of cells that could cause premature aging as a result of stem cell attrition, the killer functions of p53 are tightly regulated and balanced against protector functions that promote damage repair and support survival in response to low stress or mild damage. In molecular terms these p53-based cell fate decisions involve protein interactions with cofactors and modifying enzymes, which modulate the activation of distinct sets of p53 target genes. In addition, we demonstrate that part of this regulation occurs at the level of DNA binding. We show that the killer function of p53 requires the four DNA binding domains within the p53 tetramer to interact with one another. These intermolecular interactions enable cooperative binding of p53 to less perfect response elements in the genome, which are present in many target genes essential for apoptosis. Modulating p53 interactions within the tetramer could therefore present a novel promising strategy to fine-tune p53-based cell fate decisions.
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81
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Kleinmaier R, Keller M, Igel P, Buschauer A, Gschwind RM. Conformations, Conformational Preferences, and Conformational Exchange of N′-Substituted N-Acylguanidines: Intermolecular Interactions Hold the Key. J Am Chem Soc 2010; 132:11223-33. [DOI: 10.1021/ja103756y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Roland Kleinmaier
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Max Keller
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Patrick Igel
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Armin Buschauer
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Ruth M. Gschwind
- Institut für Organische Chemie and Institut für Pharmazie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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Villanueva T. We bonded--now make a decision. Nat Rev Cancer 2010; 10:454. [PMID: 20589971 DOI: 10.1038/nrc2881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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