1
|
Naeimzadeh Y, Tajbakhsh A, Fallahi J. Understanding the prion-like behavior of mutant p53 proteins in triple-negative breast cancer pathogenesis: The current therapeutic strategies and future directions. Heliyon 2024; 10:e26260. [PMID: 38390040 PMCID: PMC10881377 DOI: 10.1016/j.heliyon.2024.e26260] [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: 10/23/2023] [Revised: 01/20/2024] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
Breast cancer (BC) is viewed as a significant public health issue and is the primary cause of cancer-related deaths among women worldwide. Triple-negative breast cancer (TNBC) is a particularly aggressive subtype that predominantly affects young premenopausal women. The tumor suppressor p53 playsa vital role in the cellular response to DNA damage, and its loss or mutations are commonly present in many cancers, including BC. Recent evidence suggests that mutant p53 proteins can aggregate and form prion-like structures, which may contribute to the pathogenesis of different types of malignancies, such as BC. This review provides an overview of BC molecular subtypes, the epidemiology of TNBC, and the role of p53 in BC development. We also discuss the potential implications of prion-like aggregation in BC and highlight future research directions. Moreover, a comprehensive analysis of the current therapeutic approaches targeting p53 aggregates in BC treatment is presented. Strategies including small molecules, chaperone inhibitors, immunotherapy, CRISPR-Cas9, and siRNA are discussed, along with their potential benefits and drawbacks. The use of these approaches to inhibit p53 aggregation and degradation represents a promising target for cancer therapy. Future investigations into the efficacy of these approaches against various p53 mutations or binding to non-p53 proteins should be conducted to develop more effective and personalized therapies for BC treatment.
Collapse
Affiliation(s)
- Yasaman Naeimzadeh
- Department of Molecular Medicine, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, 7133654361, Iran
| | - Amir Tajbakhsh
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Jafar Fallahi
- Department of Molecular Medicine, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, 7133654361, Iran
| |
Collapse
|
2
|
Gomes AS, Ramos H, Inga A, Sousa E, Saraiva L. Structural and Drug Targeting Insights on Mutant p53. Cancers (Basel) 2021; 13:3344. [PMID: 34283062 PMCID: PMC8268744 DOI: 10.3390/cancers13133344] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/29/2021] [Accepted: 06/29/2021] [Indexed: 12/20/2022] Open
Abstract
p53 is a transcription factor with a pivotal role in cell homeostasis and fate. Its impairment is a major event in tumor onset and development. In fact, about half of human cancers bear TP53 mutations that not only halt the normal function of p53, but also may acquire oncogenic gain of functions that favor tumorigenesis. Although considered undruggable for a long time, evidence has proven the capability of many compounds to restore a wild-type (wt)-like function to mutant p53 (mutp53). However, they have not reached the clinic to date. Structural studies have strongly contributed to the knowledge about p53 structure, stability, dynamics, function, and regulation. Importantly, they have afforded relevant insights into wt and mutp53 pharmacology at molecular levels, fostering the design and development of p53-targeted anticancer therapies. Herein, we provide an integrated view of mutp53 regulation, particularly focusing on mutp53 structural traits and on targeting agents capable of its reactivation, including their biological, biochemical and biophysical features. With this, we expect to pave the way for the development of improved small molecules that may advance precision cancer therapy by targeting p53.
Collapse
Affiliation(s)
- Ana Sara Gomes
- LAQV/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal; (A.S.G.); (H.R.)
| | - Helena Ramos
- LAQV/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal; (A.S.G.); (H.R.)
| | - Alberto Inga
- Laboratory of Transcriptional Networks, Department CIBIO, University of Trento, Via Sommarive 9, 38123 Trento, Italy;
| | - Emília Sousa
- Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal;
- CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Novo Edifício do Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal
| | - Lucília Saraiva
- LAQV/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal; (A.S.G.); (H.R.)
| |
Collapse
|
3
|
Luwang JW, Nair AR, Natesh R. Stability of p53 oligomers: Tetramerization of p53 impinges on its stability. Biochimie 2021; 189:99-107. [PMID: 34197865 DOI: 10.1016/j.biochi.2021.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/21/2021] [Accepted: 06/24/2021] [Indexed: 10/21/2022]
Abstract
The p53 protein has been known to exist structurally in three different forms inside the cells. Earlier studies have reported the predominance of the lower oligomeric forms of p53 over its tetrameric form inside the cells, although only the tetrameric p53 contributes to its transcriptional activity. However, it remains unclear the functional relevance of the existence of other p53 oligomers inside the cells. In this study, we characterize the stability and conformational state of tetrameric, dimeric and monomeric p53 that spans both DNA Binding Domain (DBD) and Tetramerization Domain (TD) of human p53 (94-360 amino acid residues). Intriguingly, our studies reveal an unexpected drastic reduction in tetrameric p53 thermal stability in comparison to its dimeric and monomeric form with a higher propensity to aggregate at physiological temperature. Our EMSA study suggests that tetrameric p53, not their lower oligomeric counterpart, exhibit rapid loss of binding to their consensus DNA elements at the physiological temperature. This detrimental effect of destabilization is imparted due to the tetramerization of p53 that drives the DBDs to misfold at a faster pace when compared to its lower oligomeric form. This crosstalk between DBDs is achieved when it exists as a tetramer but not as dimer or monomer. Our findings throw light on the plausible reason for the predominant existence of p53 in dimer and monomer forms inside the cells with a lesser population of tetramer form. Therefore, the transient disruption of tetramerization between TDs could be a potential cue for the stabilization of p53 inside the cells.
Collapse
Affiliation(s)
- Johnson Wahengbam Luwang
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, 695551, Kerala, India
| | - Aadithye R Nair
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, 695551, Kerala, India
| | - Ramanathan Natesh
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, 695551, Kerala, India.
| |
Collapse
|
4
|
Li L, Li X, Tang Y, Lao Z, Lei J, Wei G. Common cancer mutations R175H and R273H drive the p53 DNA-binding domain towards aggregation-prone conformations. Phys Chem Chem Phys 2020; 22:9225-9232. [DOI: 10.1039/c9cp06671c] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cancer mutations R175H and R273H induce p53C towards aggregation-prone conformations by increasing their SASA, water exposure of H-bonds and flexibility of loop2.
Collapse
Affiliation(s)
- Le Li
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Multiscale Research Institute of Complex Systems
- Fudan University
- Shanghai 200438
| | - Xuhua Li
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Multiscale Research Institute of Complex Systems
- Fudan University
- Shanghai 200438
| | - Yiming Tang
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Multiscale Research Institute of Complex Systems
- Fudan University
- Shanghai 200438
| | - Zenghui Lao
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Multiscale Research Institute of Complex Systems
- Fudan University
- Shanghai 200438
| | - Jiangtao Lei
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Multiscale Research Institute of Complex Systems
- Fudan University
- Shanghai 200438
| | - Guanghong Wei
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Multiscale Research Institute of Complex Systems
- Fudan University
- Shanghai 200438
| |
Collapse
|
5
|
Pradhan MR, Siau JW, Kannan S, Nguyen MN, Ouaray Z, Kwoh CK, Lane DP, Ghadessy F, Verma CS. Simulations of mutant p53 DNA binding domains reveal a novel druggable pocket. Nucleic Acids Res 2019; 47:1637-1652. [PMID: 30649466 PMCID: PMC6393305 DOI: 10.1093/nar/gky1314] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 11/25/2018] [Accepted: 01/09/2019] [Indexed: 01/01/2023] Open
Abstract
The DNA binding domain (DBD) of the tumor suppressor p53 is the site of several oncogenic mutations. A subset of these mutations lowers the unfolding temperature of the DBD. Unfolding leads to the exposure of a hydrophobic β-strand and nucleates aggregation which results in pathologies through loss of function and dominant negative/gain of function effects. Inspired by the hypothesis that structural changes that are associated with events initiating unfolding in DBD are likely to present opportunities for inhibition, we investigate the dynamics of the wild type (WT) and some aggregating mutants through extensive all atom explicit solvent MD simulations. Simulations reveal differential conformational sampling between the WT and the mutants of a turn region (S6-S7) that is contiguous to a known aggregation-prone region (APR). The conformational properties of the S6-S7 turn appear to be modulated by a network of interacting residues. We speculate that changes that take place in this network as a result of the mutational stress result in the events that destabilize the DBD and initiate unfolding. These perturbations also result in the emergence of a novel pocket that appears to have druggable characteristics. FDA approved drugs are computationally screened against this pocket.
Collapse
Affiliation(s)
- Mohan R Pradhan
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), 30 Biopolis Street, #07-01 Matrix, Singapore 138671.,School of Computer Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
| | - Jia Wei Siau
- p53 Laboratory, A*STAR (Agency for Science, Technology and Research), 8A Biomedical Grove, #06-04/05, Neuros/Immunos, Singapore 138648
| | - Srinivasaraghavan Kannan
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Minh N Nguyen
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Zohra Ouaray
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), 30 Biopolis Street, #07-01 Matrix, Singapore 138671.,School of Chemistry, University of Southampton, SO17 1BJ, United Kingdom
| | - Chee Keong Kwoh
- School of Computer Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
| | - David P Lane
- p53 Laboratory, A*STAR (Agency for Science, Technology and Research), 8A Biomedical Grove, #06-04/05, Neuros/Immunos, Singapore 138648
| | - Farid Ghadessy
- p53 Laboratory, A*STAR (Agency for Science, Technology and Research), 8A Biomedical Grove, #06-04/05, Neuros/Immunos, Singapore 138648
| | - Chandra S Verma
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), 30 Biopolis Street, #07-01 Matrix, Singapore 138671.,Department of Biological sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.,School of Biological sciences, Nanyang Technological University, 50 Nanyang Drive, Singapore 637551
| |
Collapse
|
6
|
Malfatti MC, Gerratana L, Dalla E, Isola M, Damante G, Di Loreto C, Puglisi F, Tell G. APE1 and NPM1 protect cancer cells from platinum compounds cytotoxicity and their expression pattern has a prognostic value in TNBC. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:309. [PMID: 31307523 PMCID: PMC6631760 DOI: 10.1186/s13046-019-1294-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 06/25/2019] [Indexed: 02/07/2023]
Abstract
Background Triple negative breast cancer (TNBC) is a breast cancer subgroup characterized by a lack of hormone receptors’ expression and no HER2 overexpression. These molecular features both drastically reduce treatment options and confer poor prognosis. Platinum (Pt)-salts are being investigated as a new therapeutic strategy. The base excision repair (BER) pathway is important for resistance to Pt-based therapies. Overexpression of APE1, a pivotal enzyme of the BER pathway, as well as the expression of NPM1, a functional regulator of APE1, are associated with poor outcome and resistance to Pt-based therapies. Methods We evaluated the role of NPM1, APE1 and altered NPM1/APE1 interaction in the response to Pt-salts treatment in different cell lines: APE1 knockout (KO) cells, NPM1 KO cells, cell line models having an altered APE1/NPM1 interaction and HCC70 and HCC1937 TNBC cell lines, having different levels of APE1/NPM1. We evaluated the TNBC cells response to new chemotherapeutic small molecules targeting the endonuclease activity of APE1 or the APE1/NPM1 interaction, in combination with Pt-salts treatments. Expression levels’ correlation between APE1 and NPM1 and their impact on prognosis was analyzed in a cohort of TNBC patients through immunohistochemistry. Bioinformatics analysis, using TCGA datasets, was performed to predict a molecular signature of cancers based on APE1 and NPM1 expression. Results APE1 and NPM1, and their interaction as well, protect from the cytotoxicity induced by Pt-salts treatment. HCC1937 cells, having higher levels of APE1/NPM1 proteins, are more resistant to Pt-salts treatment compared to the HCC70 cells. A sensitization effect by APE1 inhibitors to Pt-compounds was observed. The association of NPM1/APE1 with cancer gene signatures highlighted alterations concerning cell-cycle dependent proteins. Conclusions APE1 and NPM1 protect cancer cells from Pt-compounds cytotoxicity, suggesting a possible improvement of the activity of Pt-based therapy for TNBC, using the NPM1 and APE1 proteins as secondary therapeutic targets. Based on positive or negative correlation with APE1 and NPM1 gene expression levels, we finally propose several TNBC gene signatures that should deserve further attention for their potential impact on TNBC precision medicine approaches. Electronic supplementary material The online version of this article (10.1186/s13046-019-1294-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
| | - Lorenzo Gerratana
- Department of Medicine (DAME), University of Udine, Piazzale M. Kolbe 4, 33100, Udine, Italy.,Department of Oncology, ASUI Udine SMM University Hospital Udine, Udine, Italy
| | - Emiliano Dalla
- Department of Medicine (DAME), University of Udine, Piazzale M. Kolbe 4, 33100, Udine, Italy
| | - Miriam Isola
- Department of Medicine (DAME), University of Udine, Piazzale M. Kolbe 4, 33100, Udine, Italy
| | - Giuseppe Damante
- Department of Medicine (DAME), University of Udine, Piazzale M. Kolbe 4, 33100, Udine, Italy
| | - Carla Di Loreto
- Department of Medicine (DAME), University of Udine, Piazzale M. Kolbe 4, 33100, Udine, Italy.,Department of Pathology, ASUI Udine SMM University Hospital Udine, Udine, Italy
| | - Fabio Puglisi
- Department of Medicine (DAME), University of Udine, Piazzale M. Kolbe 4, 33100, Udine, Italy.,Department of Medical Oncology, Centro di Riferimento Oncologico (CRO), IRCCS, Aviano, Italy
| | - Gianluca Tell
- Department of Medicine (DAME), University of Udine, Piazzale M. Kolbe 4, 33100, Udine, Italy.
| |
Collapse
|
7
|
Verkhivker GM. Biophysical simulations and structure-based modeling of residue interaction networks in the tumor suppressor proteins reveal functional role of cancer mutation hotspots in molecular communication. Biochim Biophys Acta Gen Subj 2018; 1863:210-225. [PMID: 30339916 DOI: 10.1016/j.bbagen.2018.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/06/2018] [Accepted: 10/13/2018] [Indexed: 12/19/2022]
Abstract
In the current study, we have combined molecular simulations and energetic analysis with dynamics-based network modeling and perturbation response scanning to determine molecular signatures of mutational hotspot residues in the p53, PTEN, and SMAD4 tumor suppressor proteins. By examining structure, energetics and dynamics of these proteins, we have shown that inactivating mutations preferentially target a group of structurally stable residues that play a fundamental role in global propagation of dynamic fluctuations and mediating allosteric interaction networks. Through integration of long-range perturbation dynamics and network-based approaches, we have quantified allosteric potential of residues in the studied proteins. The results have revealed that mutational hotspot sites often correspond to high centrality mediating centers of the residue interaction networks that are responsible for coordination of global dynamic changes and allosteric signaling. Our findings have also suggested that structurally stable mutational hotpots can act as major effectors of allosteric interactions and mutations in these positions are typically associated with severe phenotype. Modeling of shortest inter-residue pathways has shown that mutational hotspot sites can also serve as key mediating bridges of allosteric communication in the p53 and PTEN protein structures. Multiple regression models have indicated that functional significance of mutational hotspots can be strongly associated with the network signatures serving as robust predictors of critical regulatory positions responsible for loss-of-function phenotype. The results of this computational investigation are compared with the experimental studies and reveal molecular signatures of mutational hotspots, providing a plausible rationale for explaining and localizing disease-causing mutations in tumor suppressor genes.
Collapse
Affiliation(s)
- Gennady M Verkhivker
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, United States; Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| |
Collapse
|
8
|
Kamada R, Toguchi Y, Nomura T, Imagawa T, Sakaguchi K. Tetramer formation of tumor suppressor protein p53: Structure, function, and applications. Biopolymers 2017; 106:598-612. [PMID: 26572807 DOI: 10.1002/bip.22772] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/22/2015] [Accepted: 11/02/2015] [Indexed: 01/10/2023]
Abstract
Tetramer formation of p53 is essential for its tumor suppressor function. p53 not only acts as a tumor suppressor protein by inducing cell cycle arrest and apoptosis in response to genotoxic stress, but it also regulates other cellular processes, including autophagy, stem cell self-renewal, and reprogramming of differentiated cells into stem cells, immune system, and metastasis. More than 50% of human tumors have TP53 gene mutations, and most of them are missense mutations that presumably reduce tumor suppressor activity of p53. This review focuses on the role of the tetramerization (oligomerization), which is modulated by the protein concentration of p53, posttranslational modifications, and/or interactions with its binding proteins, in regulating the tumor suppressor function of p53. Functional control of p53 by stabilizing or inhibiting oligomer formation and its bio-applications are also discussed. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 598-612, 2016.
Collapse
Affiliation(s)
- Rui Kamada
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Yu Toguchi
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Takao Nomura
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, 060-0812, Japan
| | - Toshiaki Imagawa
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Kazuyasu Sakaguchi
- Laboratory of Biological Chemistry, Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| |
Collapse
|
9
|
Kehrloesser S, Osterburg C, Tuppi M, Schäfer B, Vousden KH, Dötsch V. Intrinsic aggregation propensity of the p63 and p73 TI domains correlates with p53R175H interaction and suggests further significance of aggregation events in the p53 family. Cell Death Differ 2016; 23:1952-1960. [PMID: 27447112 PMCID: PMC5136486 DOI: 10.1038/cdd.2016.75] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 05/19/2016] [Accepted: 06/24/2016] [Indexed: 12/20/2022] Open
Abstract
The high percentage of p53 missense mutations found in cancer has been attributed to mutant acquired oncogenic gain of functions. Different aspects of these tumour-promoting functions are caused by repression of the transcriptional activity of p53 family members p63 and p73. A subset of frequently occurring p53 mutations results in thermodynamic destabilisation of the DNA-binding domain (DBD) rendering this domain highly unstable. These conformational mutants (such as p53R175H) have been suggested to directly bind to p63 and p73 via a co-aggregation mechanism mediated by their DBDs. Although the DBDs of p63 and p73 are in fact not sufficient for the interaction as shown previously, we demonstrate here that the transactivation inhibitory (TI) domains within the α-isoform-specific C termini of p63 and p73 are essential for binding to p53R175H. Hence, the closed dimeric conformation of inactive TAp63α that renders the TI domain inaccessible prevents efficient interaction. We further show that binding to p53R175H correlates with an intrinsic aggregation propensity of the tetrameric α-isoforms conferred by an openly accessible TI domain again supporting interaction via a co-aggregation mechanism.
Collapse
Affiliation(s)
- Sebastian Kehrloesser
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance and Cluster of Excellence Macromolecular Complexes (CEF), Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Christian Osterburg
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance and Cluster of Excellence Macromolecular Complexes (CEF), Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Marcel Tuppi
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance and Cluster of Excellence Macromolecular Complexes (CEF), Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Birgit Schäfer
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance and Cluster of Excellence Macromolecular Complexes (CEF), Goethe University Frankfurt, Frankfurt/Main, Germany
| | | | - Volker Dötsch
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance and Cluster of Excellence Macromolecular Complexes (CEF), Goethe University Frankfurt, Frankfurt/Main, Germany
| |
Collapse
|
10
|
Ooms AHAG, Gadd S, Gerhard DS, Smith MA, Guidry Auvil JM, Meerzaman D, Chen QR, Hsu CH, Yan C, Nguyen C, Hu Y, Ma Y, Zong Z, Mungall AJ, Moore RA, Marra MA, Huff V, Dome JS, Chi YY, Tian J, Geller JI, Mullighan CG, Ma J, Wheeler DA, Hampton OA, Walz AL, van den Heuvel-Eibrink MM, de Krijger RR, Ross N, Gastier-Foster JM, Perlman EJ. Significance of TP53 Mutation in Wilms Tumors with Diffuse Anaplasia: A Report from the Children's Oncology Group. Clin Cancer Res 2016; 22:5582-5591. [PMID: 27702824 PMCID: PMC5290091 DOI: 10.1158/1078-0432.ccr-16-0985] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/17/2016] [Accepted: 08/14/2016] [Indexed: 12/24/2022]
Abstract
PURPOSE To investigate the role and significance of TP53 mutation in diffusely anaplastic Wilms tumors (DAWTs). EXPERIMENTAL DESIGN All DAWTs registered on National Wilms Tumor Study-5 (n = 118) with available samples were analyzed for TP53 mutations and copy loss. Integrative genomic analysis was performed on 39 selected DAWTs. RESULTS Following analysis of a single random sample, 57 DAWTs (48%) demonstrated TP53 mutations, 13 (11%) copy loss without mutation, and 48 (41%) lacked both [defined as TP53-wild-type (wt)]. Patients with stage III/IV TP53-wt DAWTs (but not those with stage I/II disease) had significantly lower relapse and death rates than those with TP53 abnormalities. In-depth analysis of a subset of 39 DAWTs showed seven (18%) to be TP53-wt: These demonstrated gene expression evidence of an active p53 pathway. Retrospective pathology review of TP53-wt DAWT revealed no or very low volume of anaplasia in six of seven tumors. When samples from TP53-wt tumors known to contain anaplasia histologically were available, abnormal p53 protein accumulation was observed by immunohistochemistry. CONCLUSIONS These data support the key role of TP53 loss in the development of anaplasia in WT, and support its significant clinical impact in patients with residual anaplastic tumor following surgery. These data also suggest that most DAWTs will show evidence of TP53 mutation when samples selected for the presence of anaplasia are analyzed. This suggests that modifications of the current criteria to also consider volume of anaplasia and documentation of TP53 aberrations may better reflect the risk of relapse and death and enable optimization of therapeutic stratification. Clin Cancer Res; 22(22); 5582-91. ©2016 AACR.
Collapse
Affiliation(s)
- Ariadne H A G Ooms
- Department of Pathology and Laboratory Medicine, Ann and Robert H. Lurie Children's Hospital of Chicago, Robert H. Lurie Cancer Center, Northwestern University, Chicago, Illinois
- Princess Maxima Centre for Pediatric Oncology, Utrecht, the Netherlands
- Department of Pathology, Pathan BV, Sint Franciscus Gasthuis, Rotterdam, the Netherlands
| | - Samantha Gadd
- Department of Pathology and Laboratory Medicine, Ann and Robert H. Lurie Children's Hospital of Chicago, Robert H. Lurie Cancer Center, Northwestern University, Chicago, Illinois
| | - Daniela S Gerhard
- Office of Cancer Genomics, National Cancer Institute, Bethesda, Maryland
| | - Malcolm A Smith
- Cancer Therapy Evaluation Program, National Cancer Institute, Bethesda, Maryland
| | | | - Daoud Meerzaman
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Bethesda, Maryland
| | - Qing-Rong Chen
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Bethesda, Maryland
| | - Chih Hao Hsu
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Bethesda, Maryland
| | - Chunhua Yan
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Bethesda, Maryland
| | - Cu Nguyen
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Bethesda, Maryland
| | - Ying Hu
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Bethesda, Maryland
| | - Yussanne Ma
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency (BCCA), Vancouver, British Columbia, Canada
| | - Zusheng Zong
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency (BCCA), Vancouver, British Columbia, Canada
| | - Andrew J Mungall
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency (BCCA), Vancouver, British Columbia, Canada
| | - Richard A Moore
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency (BCCA), Vancouver, British Columbia, Canada
| | - Marco A Marra
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency (BCCA), Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vicki Huff
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jeffrey S Dome
- Division of Pediatric Hematology/Oncology, Children's National Medical Center, Washington, DC
| | - Yueh-Yun Chi
- Department of Biostatistics, University of Florida, Gainesville, Florida
| | - Jing Tian
- Department of Biostatistics, University of Florida, Gainesville, Florida
| | - James I Geller
- Division of Pediatric Oncology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Charles G Mullighan
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Jing Ma
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - David A Wheeler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Oliver A Hampton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Amy L Walz
- Division of Hematology-Oncology and Transplantation, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University's Feinberg School of Medicine, Chicago, Illinois
- Northwestern Medicine Developmental Therapeutics Institute, Northwestern Memorial Hospital, Chicago, Illinois
| | | | - Ronald R de Krijger
- Princess Maxima Centre for Pediatric Oncology, Utrecht, the Netherlands
- Department of Pathology, Reinier de Graaf Hospital, Delft, the Netherlands
| | - Nicole Ross
- Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Ohio State University College of Medicine, Columbus, Ohio
| | - Julie M Gastier-Foster
- Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Ohio State University College of Medicine, Columbus, Ohio
- Departments of Pathology and Pediatrics, Ohio State University College of Medicine, Columbus, Ohio
| | - Elizabeth J Perlman
- Department of Pathology and Laboratory Medicine, Ann and Robert H. Lurie Children's Hospital of Chicago, Robert H. Lurie Cancer Center, Northwestern University, Chicago, Illinois.
| |
Collapse
|
11
|
Ng JWK, Lama D, Lukman S, Lane DP, Verma CS, Sim AYL. R248Q mutation--Beyond p53-DNA binding. Proteins 2015; 83:2240-50. [PMID: 26442703 DOI: 10.1002/prot.24940] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/22/2015] [Accepted: 09/29/2015] [Indexed: 01/02/2023]
Abstract
R248 in the DNA binding domain (DBD) of p53 interacts directly with the minor groove of DNA. Earlier nuclear magnetic resonance (NMR) studies indicated that the R248Q mutation resulted in conformation changes in parts of DBD far from the mutation site. However, how information propagates from the mutation site to the rest of the DBD is still not well understood. We performed a series of all-atom molecular dynamics (MD) simulations to dissect sterics and charge effects of R248 on p53-DBD conformation: (i) wild-type p53 DBD; (ii) p53 DBD with an electrically neutral arginine side-chain; (iii) p53 DBD with R248A; (iv) p53 DBD with R248W; and (v) p53 DBD with R248Q. Our results agree well with experimental observations of global conformational changes induced by the R248Q mutation. Our simulations suggest that both charge- and sterics are important in the dynamics of the loop (L3) where the mutation resides. We show that helix 2 (H2) dynamics is altered as a result of a change in the hydrogen bonding partner of D281. In turn, neighboring L1 dynamics is altered: in mutants, L1 predominantly adopts the recessed conformation and is unable to interact with the major groove of DNA. We focused our attention the R248Q mutant that is commonly found in a wide range of cancer and observed changes at the zinc-binding pocket that might account for the dominant negative effects of R248Q. Furthermore, in our simulations, the S6/S7 turn was more frequently solvent exposed in R248Q, suggesting that there is a greater tendency of R248Q to partially unfold and possibly lead to an increased aggregation propensity. Finally, based on the observations made in our simulations, we propose strategies for the rescue of R248Q mutants.
Collapse
Affiliation(s)
- Jeremy W K Ng
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore.,Bioinformatics Institute, Agency for Science, Technology, and Research, Singapore, Republic of Singapore
| | - Dilraj Lama
- Bioinformatics Institute, Agency for Science, Technology, and Research, Singapore, Republic of Singapore
| | - Suryani Lukman
- Bioinformatics Institute, Agency for Science, Technology, and Research, Singapore, Republic of Singapore.,Department of Applied Mathematics and Sciences, Khalifa University of Science, Technology, and Research, Abu Dhabi, UAE
| | - David P Lane
- p53 Laboratory, Agency for Science, Technology, and Research, Singapore, Republic of Singapore
| | - Chandra S Verma
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore.,Bioinformatics Institute, Agency for Science, Technology, and Research, Singapore, Republic of Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Adelene Y L Sim
- Bioinformatics Institute, Agency for Science, Technology, and Research, Singapore, Republic of Singapore
| |
Collapse
|
12
|
The p53 tetramer shows an induced-fit interaction of the C-terminal domain with the DNA-binding domain. Oncogene 2015; 35:3272-81. [PMID: 26477317 PMCID: PMC4929483 DOI: 10.1038/onc.2015.388] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 08/08/2015] [Accepted: 09/03/2015] [Indexed: 12/15/2022]
Abstract
The Trp53 gene is the most frequently mutated gene in all human cancers. Its protein product p53 is a very powerful transcription factor that can activate different biochemical pathways and affect the regulation of metabolism, senescence, DNA damage response, cell cycle and cell death. The understanding of its function at the molecular level could be of pivotal relevance for therapy. Investigation of long-range intra- and interdomain communications in the p53 tetramer–DNA complex was performed by means of an atomistic model that included the tetramerization helices in the C-terminal domain, the DNA-binding domains and a consensus DNA-binding site of 18 base pairs. Nonsymmetric dynamics are illustrated in the four DNA-binding domains, with loop L1 switching from inward to outward conformations with respect to the DNA major groove. Direct intra- and intermonomeric long-range communications between the tetramerization and DNA-binding domains are noted. These long-distance conformational changes link the C terminus with the DNA-binding domain and provide a biophysical rationale for the reported functional regulation of the p53 C-terminal region. A fine characterization of the DNA deformation caused by p53 binding is obtained, with ‘static' deformations always present and measured by the slide parameter in the central thymine–adenine base pairs; we also detect ‘dynamic' deformations switched on and off by particular p53 tetrameric conformations and measured by the roll and twist parameters in the same base pairs. These different conformations can indeed modulate the electrostatic potential isosurfaces of the whole p53–DNA complex. These results provide a molecular/biophysical understanding of the evident role of the C terminus in post-translational modification that regulates the transcriptional function of p53. Furthermore, the unstructured C terminus is able to facilitate contacts between the core DNA-binding domains of the tetramer.
Collapse
|
13
|
Lui K, Sheikh MS, Huang Y. Regulation of p53 oligomerization by Ras superfamily protein RBEL1A. Genes Cancer 2015; 6:307-16. [PMID: 26413214 PMCID: PMC4575918 DOI: 10.18632/genesandcancer.71] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 06/28/2015] [Indexed: 12/21/2022] Open
Abstract
Our previous studies showed that RBEL1A overexpressed in multiple human malignancies and its depletion by RNAi caused severe growth inhibition in tumor cells. We also showed that RBEL1A directly interacted with p53 and such interactions occurred at the oligomeric domain of p53. However, the effect of such interactions on p53 oligomerization and function remained to be investigated. Here, we report that the interaction of RBEL1A and p53 suppressed p53 oligomer formation in unstressed cells and in cells exposed to DNA damage. Furthermore, purified RBEL1A blocked the oligomerization of recombinant p53 corresponding to residues 315-360 in vitro. RBEL1A also significantly reduced the oligomerization of the exogenously expressed C-terminal region (residues 301-393) of p53 in cells. Overexpression of RBEL1A (as seen in human tumors), also suppressed oligomerization by endogenous p53. Our results also showed that GTPase domain of RBEL1A at residues 1-235 was sufficient to block p53 oligomerization. Furthermore, silencing of endogenous RBEL1A significantly enhanced the formation of p53 oligomeric complex following ultraviolet radiation-mediated DNA damage and RBEL1A knockdown also enhanced expression of p53 target genes. Taken together, our studies provide important new molecular insights into the regulation of p53 and the oncogenic role of RBEL1A in the context to human malignancy.
Collapse
Affiliation(s)
- Ki Lui
- Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, NY, USA ; Division of Science and Technology, The Hong Kong Polytechnic University, Hong Kong Community College, Hung Hom, Kowloon, Hong Kong
| | - M Saeed Sheikh
- Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, NY, USA
| | - Ying Huang
- Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, NY, USA
| |
Collapse
|
14
|
Conn PM, Smith E, Spicer T, Chase P, Scampavia L, Janovick JA. A phenotypic high throughput screening assay for the identification of pharmacoperones for the gonadotropin releasing hormone receptor. Assay Drug Dev Technol 2015; 12:238-46. [PMID: 24831790 DOI: 10.1089/adt.2014.576] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We describe a phenotypic high throughput screening (HTS) calcium flux assay designed to identify pharmacoperones for the gonadotropin releasing hormone receptor (GnRHR). Pharmacoperones are target-specific, small molecules that diffuse into cells, rescue misfolded protein mutants, and restore them to function. Rescue is based on correcting the trafficking of mutants that would otherwise be retained in the endoplasmic reticulum and unable to function correctly. This approach identifies drugs with a significant degree of novelty, relying on cellular mechanisms that are not currently exploited. Development of such assays is important, since the extensive use of agonist/antagonist screens alone means that useful chemical structures may be present in existing libraries but have not been previously identified using existing methods. Our assay utilizes cell lines stably expressing a GnRHR mutant under the control of a tetracycline (OFF) transactivator. This allows us to quantitate the level of functional and properly trafficked G protein coupled receptors present in each test well. Furthermore, since we are able to turn receptor expression on and off, we can rapidly eliminate the majority of false positives from our screening results. Our data show that this approach is likely to be successful in identifying hits from large chemical libraries.
Collapse
Affiliation(s)
- P Michael Conn
- 1 Departments of Internal Medicine and Cell Biology/Biochemistry, Texas Tech University Health Sciences Center , Lubbock, Texas
| | | | | | | | | | | |
Collapse
|
15
|
Saha T, Kar RK, Sa G. Structural and sequential context of p53: A review of experimental and theoretical evidence. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 117:250-263. [PMID: 25550083 DOI: 10.1016/j.pbiomolbio.2014.12.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/14/2014] [Accepted: 12/16/2014] [Indexed: 12/18/2022]
Abstract
Approximately 27 million people are suffering from cancer that contains either an inactivating missense mutation of TP53 gene or partially abrogated p53 signaling pathway. Concerted action of folded and intrinsically disordered domains accounts for multi-faceted role of p53. The intricacy of dynamic p53 structure is believed to shed light on its cellular activity for developing new cancer therapies. In this review, insights into structural details of p53, diverse single point mutations affecting its core domain, thermodynamic understanding and therapeutic strategies for pharmacological rescue of p53 function has been illustrated. An effort has been made here to bridge the structural and sequential evidence of p53 from experimental to computational studies. First, we focused on the individual domains and the crucial protein-protein or DNA-protein contacts that determine conformation and dynamic behavior of p53. Next, the oncogenic mutations associated with cancer and its contribution to thermodynamic fluctuation has been discussed. Thus the emerging anti-cancer strategies include targeting of destabilized cancer mutants with selective inhibition of its negative regulators. Recent advances in development of small molecule inhibitors and peptides exploiting p53-MDM2 interaction has been included. In a nutshell, this review attempts to describe structural biology of p53 which provide new openings for structure-guided rescue.
Collapse
Affiliation(s)
- Taniya Saha
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata 700054, India
| | - Rajiv K Kar
- Division of Biophysics, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata 700054, India
| | - Gaurisankar Sa
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata 700054, India.
| |
Collapse
|
16
|
Gañán-Gómez I, Estañ-Omaña MC, Sancho P, Aller P, Boyano-Adánez MC. Mechanisms of resistance to apoptosis in the human acute promyelocytic leukemia cell line NB4. Ann Hematol 2014; 94:379-92. [PMID: 25322811 DOI: 10.1007/s00277-014-2237-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 10/07/2014] [Indexed: 12/31/2022]
Abstract
Current frontline therapies have improved overall survival in acute promyelocytic leukemia (APL) patients to exceptional rates; however, relapse is still a problem among high-risk and old patients. Therefore, the development of better and safer therapies continues to be a goal in the treatment of this disease. In the present work, we examined three different pathways that hinder cell death in the APL cell line NB4, shedding light on the mechanisms that underlie resistance to apoptosis in these cells and that might help provide them with a proliferative advantage. We found that the proteasome inhibitor MG-132 specifically induces in NB4 cells an Nrf2-mediated antioxidant response which counteracts mitochondria-dependent apoptosis induced by the lipophilic cation dequalinium. More importantly, we also demonstrated that high basal autophagy levels and the gain-of-function of mutant p53 are intrinsic mechanisms of resistance to apoptosis in this cell line. According to our results, the pharmacological inhibition of autophagy and p53 mutants are useful tools to explore resistance to apoptosis in APL and other types of cancer and could be the bases of new therapeutic approaches that improve the efficiency and allow dose reduction of the current treatments.
Collapse
MESH Headings
- Antineoplastic Combined Chemotherapy Protocols/pharmacology
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Antioxidants/metabolism
- Apoptosis/drug effects
- Apoptosis/genetics
- Cell Line, Tumor
- Cell Nucleus/drug effects
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Dequalinium/administration & dosage
- Dequalinium/pharmacology
- Dose-Response Relationship, Drug
- Drug Resistance, Neoplasm/genetics
- Gene Expression Regulation, Leukemic/drug effects
- HL-60 Cells
- Humans
- Leukemia, Promyelocytic, Acute/drug therapy
- Leukemia, Promyelocytic, Acute/genetics
- Leukemia, Promyelocytic, Acute/pathology
- Leupeptins/administration & dosage
- Leupeptins/pharmacology
- Protein Transport/drug effects
- Tumor Suppressor Protein p53/metabolism
Collapse
Affiliation(s)
- I Gañán-Gómez
- Department of System Biology, Unit of Biochemistry and Molecular Biology, Faculty of Medicine and Health Sciences, University of Alcalá (UAH), Carretera Madrid-Barcelona Km 33.6 s/n, 28871, Alcalá de Henares, Madrid, Spain
| | | | | | | | | |
Collapse
|
17
|
Sun Y, Myers CJ, Dicker AP, Lu B. A novel radiation-induced p53 mutation is not implicated in radiation resistance via a dominant-negative effect. PLoS One 2014; 9:e87492. [PMID: 24558369 PMCID: PMC3928108 DOI: 10.1371/journal.pone.0087492] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 12/27/2013] [Indexed: 11/19/2022] Open
Abstract
Understanding the mutations that confer radiation resistance is crucial to developing mechanisms to subvert this resistance. Here we describe the creation of a radiation resistant cell line and characterization of a novel p53 mutation. Treatment with 20 Gy radiation was used to induce mutations in the H460 lung cancer cell line; radiation resistance was confirmed by clonogenic assay. Limited sequencing was performed on the resistant cells created and compared to the parent cell line, leading to the identification of a novel mutation (del) at the end of the DNA binding domain of p53. Levels of p53, phospho-p53, p21, total caspase 3 and cleaved caspase 3 in radiation resistant cells and the radiation susceptible (parent) line were compared, all of which were found to be similar. These patterns held true after analysis of p53 overexpression in H460 cells; however, H1299 cells transfected with mutant p53 did not express p21, whereas those given WT p53 produced a significant amount, as expected. A luciferase assay demonstrated the inability of mutant p53 to bind its consensus elements. An MTS assay using H460 and H1299 cells transfected with WT or mutant p53 showed that the novel mutation did not improve cell survival. In summary, functional characterization of a radiation-induced p53 mutation in the H460 lung cancer cell line does not implicate it in the development of radiation resistance.
Collapse
Affiliation(s)
- Yunguang Sun
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Carey Jeanne Myers
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Adam Paul Dicker
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Bo Lu
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
18
|
He Y, Gong J, Wang Y, Qin Z, Jiang Y, Ma H, Jin G, Chen J, Hu Z, Guan X, Shen H. Potentially functional polymorphisms in aminoacyl-tRNA synthetases genes are associated with breast cancer risk in a Chinese population. Mol Carcinog 2014; 54:577-83. [DOI: 10.1002/mc.22128] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 11/13/2013] [Accepted: 12/12/2013] [Indexed: 11/12/2022]
Affiliation(s)
- Yisha He
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
| | - Jianhang Gong
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
| | - Yanru Wang
- Department of Medical Oncology; Jinling Hospital; Southern Medical University; 305 East Zhongshan Road, Nanjing Jiangsu Province P.R. China
| | - Zhenzhen Qin
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
- State Key Laboratory of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing P.R. China
| | - Yue Jiang
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
- State Key Laboratory of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing P.R. China
| | - Hongxia Ma
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
- State Key Laboratory of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing P.R. China
| | - Guangfu Jin
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
- State Key Laboratory of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing P.R. China
| | - Jiaping Chen
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
| | - Zhibin Hu
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
- State Key Laboratory of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing P.R. China
| | - Xiaoxiang Guan
- Department of Medical Oncology; Jinling Hospital; Southern Medical University; 305 East Zhongshan Road, Nanjing Jiangsu Province P.R. China
| | - Hongbing Shen
- Department of Epidemiology and Biostatistics; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Cancer Center; School of Public Health; Nanjing Medical University; Nanjing Jiangsu P.R. China
- State Key Laboratory of Reproductive Medicine; Institute of Toxicology; Nanjing Medical University; Nanjing P.R. China
| |
Collapse
|
19
|
Conn PM, Smithson DC, Hodder PS, Stewart MD, Behringer RR, Smith E, Ulloa-Aguirre A, Janovick JA. Transitioning pharmacoperones to therapeutic use: in vivo proof-of-principle and design of high throughput screens. Pharmacol Res 2013; 83:38-51. [PMID: 24373832 DOI: 10.1016/j.phrs.2013.12.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/16/2013] [Accepted: 12/16/2013] [Indexed: 12/26/2022]
Abstract
A pharmacoperone (from "pharmacological chaperone") is a small molecule that enters cells and serves as molecular scaffolding in order to cause otherwise-misfolded mutant proteins to fold and route correctly within the cell. Pharmacoperones have broad therapeutic applicability since a large number of diseases have their genesis in the misfolding of proteins and resultant misrouting within the cell. Misrouting may result in loss-of-function and, potentially, the accumulation of defective mutants in cellular compartments. Most known pharmacoperones were initially derived from receptor antagonist screens and, for this reason, present a complex pharmacology, although these are highly target specific. In this summary, we describe efforts to produce high throughput screens that identify these molecules from chemical libraries as well as a mouse model which provides proof-of-principle for in vivo protein rescue using existing pharmacoperones.
Collapse
Affiliation(s)
- P Michael Conn
- Department of Internal Medicine, Texas Tech University Health Science Center, 3601 4th Street, Lubbock, TX 79430, United States; Department of Cell Biology, Texas Tech University Health Science Center, 3601 4th Street, Lubbock, TX 79430, United States.
| | - David C Smithson
- Oregon Translational Research and Drug Development Institute (OTRADI), Portland, OR 97201, United States
| | - Peter S Hodder
- Translational Research Institute, Scripps Research Institute, Jupiter, FL 33458, United States
| | - M David Stewart
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, United States; Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, United States
| | - Richard R Behringer
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, United States
| | - Emery Smith
- Translational Research Institute, Scripps Research Institute, Jupiter, FL 33458, United States
| | - Alfredo Ulloa-Aguirre
- Research Support Network, Instituto Nacional de Ciencias Medicas y Nutricion, S-Z Universidad Autonoma de Mexico, Mexico, D.F., Mexico
| | - Jo Ann Janovick
- Department of Internal Medicine, Texas Tech University Health Science Center, 3601 4th Street, Lubbock, TX 79430, United States; Department of Cell Biology, Texas Tech University Health Science Center, 3601 4th Street, Lubbock, TX 79430, United States
| |
Collapse
|
20
|
Mapping the structural and dynamical features of multiple p53 DNA binding domains: insights into loop 1 intrinsic dynamics. PLoS One 2013; 8:e80221. [PMID: 24324553 PMCID: PMC3855832 DOI: 10.1371/journal.pone.0080221] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 09/30/2013] [Indexed: 11/19/2022] Open
Abstract
The transcription factor p53 regulates cellular integrity in response to stress. p53 is mutated in more than half of cancerous cells, with a majority of the mutations localized to the DNA binding domain (DBD). In order to map the structural and dynamical features of the DBD, we carried out multiple copy molecular dynamics simulations (totaling 0.8 μs). Simulations show the loop 1 to be the most dynamic element among the DNA-contacting loops (loops 1-3). Loop 1 occupies two major conformational states: extended and recessed; the former but not the latter displays correlations in atomic fluctuations with those of loop 2 (~24 Å apart). Since loop 1 binds to the major groove whereas loop 2 binds to the minor groove of DNA, our results begin to provide some insight into the possible mechanism underpinning the cooperative nature of DBD binding to DNA. We propose (1) a novel mechanism underlying the dynamics of loop 1 and the possible tread-milling of p53 on DNA and (2) possible mutations on loop 1 residues to restore the transcriptional activity of an oncogenic mutation at a distant site.
Collapse
|
21
|
Barros T, Guenther J, Kelch B, Anaya J, Prabhakar A, O'Donnell M, Kuriyan J, Lamers MH. A structural role for the PHP domain in E. coli DNA polymerase III. BMC STRUCTURAL BIOLOGY 2013; 13:8. [PMID: 23672456 PMCID: PMC3666897 DOI: 10.1186/1472-6807-13-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/07/2013] [Indexed: 12/05/2022]
Abstract
Background In addition to the core catalytic machinery, bacterial replicative DNA polymerases contain a Polymerase and Histidinol Phosphatase (PHP) domain whose function is not entirely understood. The PHP domains of some bacterial replicases are active metal-dependent nucleases that may play a role in proofreading. In E. coli DNA polymerase III, however, the PHP domain has lost several metal-coordinating residues and is likely to be catalytically inactive. Results Genomic searches show that the loss of metal-coordinating residues in polymerase PHP domains is likely to have coevolved with the presence of a separate proofreading exonuclease that works with the polymerase. Although the E. coli Pol III PHP domain has lost metal-coordinating residues, the structure of the domain has been conserved to a remarkable degree when compared to that of metal-binding PHP domains. This is demonstrated by our ability to restore metal binding with only three point mutations, as confirmed by the metal-bound crystal structure of this mutant determined at 2.9 Å resolution. We also show that Pol III, a large multi-domain protein, unfolds cooperatively and that mutations in the degenerate metal-binding site of the PHP domain decrease the overall stability of Pol III and reduce its activity. Conclusions While the presence of a PHP domain in replicative bacterial polymerases is strictly conserved, its ability to coordinate metals and to perform proofreading exonuclease activity is not, suggesting additional non-enzymatic roles for the domain. Our results show that the PHP domain is a major structural element in Pol III and its integrity modulates both the stability and activity of the polymerase.
Collapse
Affiliation(s)
- Tiago Barros
- Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Ou Y, Ma L, Ma L, Huang Z, Zhou W, Zhao C, Zhang B, Song Y, Yu C, Zhan Q. Overexpression of cyclin B1 antagonizes chemotherapeutic-induced apoptosis through PTEN/Akt pathway in human esophageal squamous cell carcinoma cells. Cancer Biol Ther 2012; 14:45-55. [PMID: 23114644 DOI: 10.4161/cbt.22627] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The role of cyclin B1 in the clinical therapeutic sensitivity of human esophageal squamous cell carcinoma (ESCC) remains to be defined. In this study, we found that elevated cyclin B1 expression attenuated the apoptosis induced by cisplatin or paclitaxel, while knockdown of cyclin B1 enhanced cisplatin or paclitaxel sensitivity in ESCC cells. Cyclin B1-mediated apoptosis may rely on the Bcl-2-dependent mitochondria-regulated intrinsic death pathway, and the antagonizing effect of cyclin B1 on chemotherapeutic agent-induced apoptosis was through PTEN/Akt pathway. Therefore, cyclin B1 might be a therapeutic target for the development of specific and efficient approaches in the treatment of ESCC.
Collapse
Affiliation(s)
- Yunwei Ou
- State Key Laboratory of Molecular Oncology, Cancer Institute and Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Retzlaff M, Rohrberg J, Küpper NJ, Lagleder S, Bepperling A, Manzenrieder F, Peschek J, Kessler H, Buchner J. The regulatory domain stabilizes the p53 tetramer by intersubunit contacts with the DNA binding domain. J Mol Biol 2012; 425:144-55. [PMID: 23103206 DOI: 10.1016/j.jmb.2012.10.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 10/16/2012] [Accepted: 10/18/2012] [Indexed: 12/24/2022]
Abstract
The tumor suppressor protein p53 is often referred to as the guardian of the genome. In the past, controversial findings have been presented for the role of the C-terminal regulatory domain (RD) of p53 as both a negative regulator and a positive regulator of p53 activity. However, the underlying mechanism remained enigmatic. To understand the function of the RD and of a dominant phosphorylation site within the RD, we analyzed p53 variants in vivo and in vitro. Our experiments revealed, surprisingly, that the p53 RD of one subunit interacts with the DNA binding domain of an adjacent subunit in the tetramer. This leads to the formation of intersubunit contacts that stabilize the tetrameric state of p53 and enhance its transcriptional activity in a cooperative manner. These effects are further modulated by phosphorylation of a conserved serine within the RD.
Collapse
Affiliation(s)
- Marco Retzlaff
- Center for Integrated Protein Science Munich at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
First-order rate-determining aggregation mechanism of p53 and its implications. Proc Natl Acad Sci U S A 2012; 109:13590-5. [PMID: 22869710 DOI: 10.1073/pnas.1211557109] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aggregation of p53 is initiated by first-order processes that generate an aggregation-prone state with parallel pathways of major or partial unfolding. Here, we elaborate the mechanism and explore its consequences, beginning with the core domain and extending to the full-length p53 mutant Y220C. Production of large light-scattering particles was slower than formation of the Thioflavin T-binding state and simultaneous depletion of monomer. EDTA removes Zn(2+) to generate apo-p53, which aggregated faster than holo-p53. Apo-Y220C also aggregated by both partial and major unfolding. Apo-p53 was not an obligatory intermediate in the aggregation of holo-p53, but affords a parallel pathway that may be relevant to oncogenic mutants with impaired Zn(2+) binding. Full-length tetrameric Y220C formed the Thioflavin T-binding state with similar rate constants to those of core domain, consistent with a unimolecular initiation that is unaffected by neighboring subunits, but very slowly formed small light-scattering particles. Apo-Y220C and aggregated holo-Y220C had little, if any, seeding effect on the initial polymerization of holo-Y220C (measured by Thioflavin T binding), consistent with initiation being a unimolecular process. But apo-Y220C and aggregated holo-Y220C accelerated somewhat the subsequent formation of light-scattering particles from holo-protein, implying coaggregation. The implications for cancer cells containing wild-type and unstable mutant alleles are that aggregation of wild-type p53 (or homologs) might not be seeded by aggregated mutant, but it could coaggregate with p53 or other cellular proteins that have undergone the first steps of aggregation and speed up the formation of microscopically observable aggregates.
Collapse
|
25
|
Molecular dynamic simulation insights into the normal state and restoration of p53 function. Int J Mol Sci 2012; 13:9709-9740. [PMID: 22949826 PMCID: PMC3431824 DOI: 10.3390/ijms13089709] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/06/2012] [Accepted: 07/11/2012] [Indexed: 12/13/2022] Open
Abstract
As a tumor suppressor protein, p53 plays a crucial role in the cell cycle and in cancer prevention. Almost 50 percent of all human malignant tumors are closely related to a deletion or mutation in p53. The activity of p53 is inhibited by over-active celluar antagonists, especially by the over-expression of the negative regulators MDM2 and MDMX. Protein-protein interactions, or post-translational modifications of the C-terminal negative regulatory domain of p53, also regulate its tumor suppressor activity. Restoration of p53 function through peptide and small molecular inhibitors has become a promising strategy for novel anti-cancer drug design and development. Molecular dynamics simulations have been extensively applied to investigate the conformation changes of p53 induced by protein-protein interactions and protein-ligand interactions, including peptide and small molecular inhibitors. This review focuses on the latest MD simulation research, to provide an overview of the current understanding of interactions between p53 and its partners at an atomic level.
Collapse
|
26
|
Abstract
Background Large-scale tumor sequencing projects are now underway to identify genetic mutations that drive tumor initiation and development. Most studies take a gene-based approach to identifying driver mutations, highlighting genes mutated in a large percentage of tumor samples as those likely to contain driver mutations. However, this gene-based approach usually does not consider the position of the mutation within the gene or the functional context the position of the mutation provides. Here we introduce a novel method for mapping mutations to distinct protein domains, not just individual genes, in which they occur, thus providing the functional context for how the mutation contributes to disease. Furthermore, aggregating mutations from all genes containing a specific protein domain enables the identification of mutations that are rare at the gene level, but that occur frequently within the specified domain. These highly mutated domains potentially reveal disruptions of protein function necessary for cancer development. Results We mapped somatic mutations from the protein coding regions of 100 colon adenocarcinoma tumor samples to the genes and protein domains in which they occurred, and constructed topographical maps to depict the “mutational landscapes” of gene and domain mutation frequencies. We found significant mutation frequency in a number of genes previously known to be somatically mutated in colon cancer patients including APC, TP53 and KRAS. In addition, we found significant mutation frequency within specific domains located in these genes, as well as within other domains contained in genes having low mutation frequencies. These domain “peaks” were enriched with functions important to cancer development including kinase activity, DNA binding and repair, and signal transduction. Conclusions Using our method to create the domain landscapes of mutations in colon cancer, we were able to identify somatic mutations with high potential to drive cancer development. Interestingly, the majority of the genes involved have a low mutation frequency. Therefore, themethod shows good potential for identifying rare driver mutations in current, large-scale tumor sequencing projects. In addition, mapping mutations to specific domains provides the necessary functional context for understanding how the mutations contribute to the disease, and may reveal novel or more refined gene and domain target regions for drug development.
Collapse
Affiliation(s)
- Nathan L Nehrt
- Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | | | | | | |
Collapse
|
27
|
Prolyl cis/trans isomerase signalling pathways in cancer. Curr Opin Pharmacol 2011; 11:281-7. [DOI: 10.1016/j.coph.2011.03.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 03/21/2011] [Indexed: 01/05/2023]
|
28
|
Mihai DM, Deng H, Kawamura A. Reproducible enrichment of extracellular heat shock proteins from blood serum using monomeric avidin. Bioorg Med Chem Lett 2011; 21:4134-7. [PMID: 21689931 DOI: 10.1016/j.bmcl.2011.05.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 10/18/2022]
Abstract
Extracellular heat shock proteins (eHsps) in blood circulation have been associated with various diseases, including cancer. However, the lack of methods to enrich eHsps from serum samples has hampered the characterization of eHsps. This Letter presents our serendipitous finding that the monomeric avidin resin can serve as an affinity resin to enrich eHsps from blood serum. Biochemical mechanism of this eHsp enrichment as well as implications in biomarker discovery is discussed.
Collapse
Affiliation(s)
- Doina M Mihai
- Department of Chemistry, Hunter College of CUNY, 695 Park Avenue, New York, NY 10065, USA
| | | | | |
Collapse
|
29
|
Interaction of the p53 DNA-binding domain with its n-terminal extension modulates the stability of the p53 tetramer. J Mol Biol 2011; 409:358-68. [PMID: 21457718 PMCID: PMC3176915 DOI: 10.1016/j.jmb.2011.03.047] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 03/22/2011] [Accepted: 03/23/2011] [Indexed: 12/30/2022]
Abstract
The tetrameric tumor suppressor p53 plays a pivotal role in the control of the cell cycle and provides a paradigm for an emerging class of oligomeric, multidomain proteins with structured and intrinsically disordered regions. Many of its biophysical and functional properties have been extrapolated from truncated variants, yet the exact structural and functional role of certain segments of the protein is unclear. We found from NMR and X-ray crystallography that the DNA-binding domain (DBD) of human p53, usually defined as residues 94-292, extends beyond these domain boundaries. Trp91, in the hinge region between the disordered proline-rich N-terminal domain and the DBD, folds back onto the latter and has a cation-π interaction with Arg174. These additional interactions increase the melting temperature of the DBD by up to 2 °C and inhibit aggregation of the p53 tetramer. They also modulate the dissociation of the p53 tetramer. The absence of the Trp91/Arg174 packing presumably allows nonnative DBD-DBD interactions that both nucleate aggregation and stabilize the interface. These data have important implications for studies of multidomain proteins in general, highlighting the fact that weak ordered-disordered domain interactions can modulate the properties of proteins of complex structure.
Collapse
|
30
|
Calhoun S, Daggett V. Structural effects of the L145Q, V157F, and R282W cancer-associated mutations in the p53 DNA-binding core domain. Biochemistry 2011; 50:5345-53. [PMID: 21561095 DOI: 10.1021/bi200192j] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The p53 tumor suppressor is a transcription factor involved in many important signaling pathways, such as apoptosis and cell-cycle arrest. In over half of human cancers, p53 function is compromised by a mutation in its gene. Mutations in the p53 DNA-binding core domain destabilize the structure and reduce DNA-binding activity. We performed molecular dynamics simulations at physiological temperature to study the structural and dynamic effects of the L145Q, V157F, and R282W cancer-associated mutations in comparison to the wild-type protein. While there were common regions of destabilization in the mutant simulations, structural changes particular to individual mutations were also observed. Significant backbone deviations of the H2 helix and S7-S8 loop were observed in all mutant simulations; the H2 helix binds to DNA. In addition, the L145Q and V157F mutations, which are located in the β-sandwich core of the domain, disrupted the β-sheet structure and the loop-sheet-helix motif. The R282W mutation caused distortion of the loop-sheet-helix motif, but otherwise this mutant was similar to the wild-type structure. The introduction of these mutations caused rearrangement of the DNA-binding surface, consistent with their reduced DNA-binding activity. The simulations reveal detailed effects of the mutations on the stability and dynamics of p53 that may provide insight for therapeutic approaches.
Collapse
Affiliation(s)
- Sara Calhoun
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013, USA
| | | |
Collapse
|
31
|
Singh OV. Protein-misfolding diseases and the paradigm of proteomics-based therapeutic targets. Expert Rev Proteomics 2010; 7:463-4. [PMID: 20653501 DOI: 10.1586/epr.10.71] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Om V Singh
- Division of Biological and Health Sciences, University of Pittsburgh, Bradford, PA 16701, USA.
| |
Collapse
|
32
|
Abstract
The p53 tumor suppressor is a transcription factor that contains a single zinc ion near its DNA binding interface. Zn(2+) is required for site-specific DNA binding and proper transcriptional activation. In addition to its functional significance, zinc plays a dominant role in determining whether p53 folds productively or misfolds. Insufficient zinc and excess zinc cause p53 to misfold by distinct mechanisms which both result in functional loss. The zinc-binding status of p53 in the cell is impacted significantly by the presence of tumorigenic mutations and by metal ion homeostasis. This review discusses mechanisms by which zinc modulates folding and misfolding of p53, how improper metal binding and release leads to loss of function and cancer, and how misfolding can be rescued by metallochaperones.
Collapse
Affiliation(s)
- Stewart N Loh
- Department of Biochemistry & Molecular Biology, State University of New York Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA
| |
Collapse
|