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Mondal P, Roy KS, Bhagat SV, Singh S, Chattopadhyay A, Ghosh DD, Kundu TK, Roychoudhury S, Roy S. Disrupting the interaction between a p53 gain-of-function mutant and the transcriptional co-activator PC4 reverses drug resistance in cancer cells. FEBS Lett 2024; 598:1532-1542. [PMID: 38664232 DOI: 10.1002/1873-3468.14890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 01/21/2024] [Accepted: 02/13/2024] [Indexed: 06/27/2024]
Abstract
PC4 is a chromatin-associated protein and transcriptional coactivator whose role in gene regulation by wild-type p53 is now well known. Little is known about the roles of PC4 in tumor cells bearing mutant p53 genes. We show that PC4 associates with one of the tumor-associated gain-of-function p53 mutants, R273H. This association drives its recruitment to two promoters, UBE2C and MDR1, known to be responsible for imparting aggressive growth and resistance to many drugs. Here, we introduced a peptide that disrupts the PC4-R273Hp53 interaction to tumor cells bearing the R273HTP53 gene, which led to a lowering of MDR1 expression and abrogation of drug resistance in a mutant-specific manner. The results suggest that the PC4-R273Hp53 interaction may be a promising target for reducing proliferation and drug resistance in tumors.
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Affiliation(s)
- Priya Mondal
- Department of Biophysics, Bose Institute, Kolkata, India
| | - Kumar Singha Roy
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Supriya Varsha Bhagat
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Siddharth Singh
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | | | | | - Tapas K Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Susanta Roychoudhury
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Siddhartha Roy
- Department of Biophysics, Bose Institute, Kolkata, India
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2
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Yao X, Xu X, Hu K, Yang Z, Deng S. BANF1 promotes glutamate-induced apoptosis of HT-22 hippocampal neurons. Mol Biol Rep 2023; 50:9441-9452. [PMID: 37838622 DOI: 10.1007/s11033-023-08889-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 10/04/2023] [Indexed: 10/16/2023]
Abstract
BACKGROUND Glutamate exposure was fatal to HT-22 neuronal cells that derived from mouse hippocampus. This is often used as a model for hippocampus neurodegeneration in vitro. The targets relevant to glutamate-induced neuronal toxicity is not fully understood. In this study, we aimed to identify crucial factors associated with glutamate-induced cytotoxicity in HT-22 cells. METHODS HT-22 cells were treated with 7.5 mM glutamate for 24 h and isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis conducted to identify the differentially expressed proteins. Differential proteins were subjected to Gene Ontology analyses. Upregulation of barrier to autointegration factor (BANF1/BANF1) protein was confirmed by RT-qPCR and western blotting. Cell viability was measured by CKK-8 and MTT assays. Cell apoptosis rates and intracellular reactive oxygen species (ROS) levels were detected using flow cytometry. RESULTS A total of 5811 proteins were quantified by iTRAQ, 50 of which were recognized as significantly differential proteins (fold change ≥ 1.5 and P ≤ 0.05); 26 proteins were up-regulated and 24 were down-regulated after exposure to glutamate. GO enrichment analysis showed that the apoptotic signaling pathway was involved in cell death induced by glutamate. BANF1 expression level was markedly increased in HT-22 cells after glutamate treatment. Further, knockdown of BANF1 alleviated glutamate-mediated cell death with lower ROS levels. CONCLUSIONS In conclusion, we successfully filtered out differential proteins relevant to glutamate-mediated cytotoxicity. BANF1 upregulation promoted glutamate-induced apoptosis of HT-22 cells by enhancing ROS generation.
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Affiliation(s)
- Xinyu Yao
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xiaoyi Xu
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, Guangdong, China
| | - Kunhua Hu
- Proteomics Research Center, Sun Yat-Sen Medical College of Sun Yat-Sen University, Guangzhou, 510080, China
| | - Zhaoshou Yang
- The First Affiliated Hospital/School of Clinical Medicine of Guangdong Pharmaceutical University, Guangdong Pharmaceutical University, Guangzhou, 510080, China.
| | - Shaodong Deng
- The First Dongguan Affiliated Hospital of Guangdong Medical University, Dongguan, 523710, Guangdong, China.
- Scientific Research Platform, The Second Clinical Medical College, Guangdong Medical University, Dongguan, 523808, China.
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3
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Chatterjee C, Singh SK. Peptide and protein chemistry approaches to study the tumor suppressor protein p53. Org Biomol Chem 2022; 20:5500-5509. [PMID: 35786742 PMCID: PMC10112546 DOI: 10.1039/d2ob00902a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The tumor suppressor and master gene regulator protein p53 has been the subject of intense investigation for several decades due to its mutation in about half of all human cancers. However, mechanistic studies of p53 in cells are complicated by its many dynamic binding partners and heterogeneous post-translational modifications. The design of therapeutics that rescue p53 functions in cells requires a mechanistic understanding of its protein-protein interactions in specific protein complexes and identifying changes in p53 activity by diverse post-translational modifications. This review highlights the important roles that peptide and protein chemistry have played in biophysical and biochemical studies aimed at elucidating p53 regulation by several key binding partners. The design of various peptide inhibitors that rescue p53 function in cells and new opportunities in targeting p53-protein interactions are discussed. In addition, the review highlights the importance of a protein semisynthesis approach to comprehend the role of site-specific PTMs in p53 regulation.
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Affiliation(s)
- Champak Chatterjee
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA.
| | - Sumeet K Singh
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA.
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4
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Mustafi P, Hu M, Kumari S, Das C, Li G, Kundu T. Phosphorylation-dependent association of human chromatin protein PC4 to linker histone H1 regulates genome organization and transcription. Nucleic Acids Res 2022; 50:6116-6136. [PMID: 35670677 PMCID: PMC9226532 DOI: 10.1093/nar/gkac450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 05/08/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022] Open
Abstract
Human Positive Coactivator 4 (PC4) is a multifaceted chromatin protein involved in diverse cellular processes including genome organization, transcription regulation, replication, DNA repair and autophagy. PC4 exists as a phospho-protein in cells which impinges on its acetylation by p300 and thereby affects its transcriptional co-activator functions via double-stranded DNA binding. Despite the inhibitory effects, the abundance of phosphorylated PC4 in cells intrigued us to investigate its role in chromatin functions in a basal state of the cell. We found that casein kinase-II (CKII)-mediated phosphorylation of PC4 is critical for its interaction with linker histone H1. By employing analytical ultracentrifugation and electron microscopy imaging of in vitro reconstituted nucleosomal array, we observed that phospho-mimic (PM) PC4 displays a superior chromatin condensation potential in conjunction with linker histone H1. ATAC-sequencing further unveiled the role of PC4 phosphorylation to be critical in inducing chromatin compaction of a wide array of coding and non-coding genes in vivo. Concordantly, phospho-PC4 mediated changes in chromatin accessibility led to gene repression and affected global histone modifications. We propose that the abundance of PC4 in its phosphorylated state contributes to genome compaction contrary to its co-activator function in driving several cellular processes like gene transcription and autophagy.
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Affiliation(s)
- Pallabi Mustafi
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Mingli Hu
- National laboratory of Bio-macromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China
| | - Sujata Kumari
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Chandrima Das
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Guohong Li
- National laboratory of Bio-macromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China
| | - Tapas K Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
- Division of Neuroscience and Ageing Biology, CSIR-Central Drug Research Institute, Sitapur Road, Sector 10, Jankipuram Extension, Lucknow 226031, India
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5
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Cigrovski Berkovic M, Ulamec M, Marinovic S, Balen I, Mrzljak A. Malignant insulinoma: Can we predict the long-term outcomes? World J Clin Cases 2022; 10:5124-5132. [PMID: 35812675 PMCID: PMC9210919 DOI: 10.12998/wjcc.v10.i16.5124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 01/17/2022] [Accepted: 04/21/2022] [Indexed: 02/06/2023] Open
Abstract
Insulinomas are the most frequent type of functional pancreatic neuroendocrine tumors with a variety of neuroglycopenic and autonomic symptoms and well-defined diagnostic criteria; however, prediction of their clinical behavior and early differentiation between benign and malignant lesions remain a challenge. The comparative studies between benign and malignant cases are limited, suggesting that short clinical history, early hypoglycemia during fasting, high proinsulin, insulin, and C-peptide concentrations raise suspicion of malignancy. Indeed, malignant tumors are larger with higher mitotic count and Ki-67 proliferative activity, but there are no accurate histological criteria to distinguish benign from malignant forms. Several signaling pathways have been suggested to affect the pathophysiology and behavior of insulinomas; however, our knowledge is limited, urging a further understanding of molecular genetics. Therefore, there is a need for the identification of reliable markers of metastatic disease that could also serve as therapeutic targets in patients with malignant insulinoma. This opinion review reflects on current gaps in diagnostic and clinical aspects related to the malignant behavior of insulinoma.
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Affiliation(s)
- Maja Cigrovski Berkovic
- Department of Endocrinology, Diabetes, Metabolism and Clinical Pharmacology, Clinical Hospital Dubrava, Zagreb 10000, Croatia
- Department of Kinesiological Anthropology and Methodology, Faculty of Kinesiology, University of Zagreb, Zagreb 10000, Croatia
| | - Monika Ulamec
- Department of Pathology and Cytology “Ljudevit Jurak”, University Hospital Center “Sestre milosrdnice”, Zagreb 10000, Croatia
- Scientific Group for Research on Epigenetic Biomarkers and Department of Pathology, School of Medicine, University of Zagreb, Zagreb 10000, Croatia
| | - Sonja Marinovic
- Laboratory for Personalized Medicine, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb 10000, Croatia
| | - Ivan Balen
- Department of Gastroenterology and Endocrinology, General Hospital “Dr. Josip Bencevic”, Slavonski Brod 35000, Croatia
| | - Anna Mrzljak
- Department of Gastroenterology and Hepatology, UHC Zagreb, Zagreb 10000, Croatia
- School of Medicine, University of Zagreb, Zagreb 10000, Croatia
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6
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Pandey B, Dev A, Chakravorty D, Bhandare VV, Polley S, Roy S, Basu G. Insights on the disruption of the complex between human positive coactivator 4 and p53 by small molecules. Biochem Biophys Res Commun 2021; 578:15-20. [PMID: 34534740 DOI: 10.1016/j.bbrc.2021.09.020] [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: 08/07/2021] [Revised: 08/29/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
Interaction between human positive coactivator 4 (PC4), an abundant nuclear protein, and the tumor suppressor protein p53 plays a crucial role in initiating apoptosis. In certain neurodegenerative diseases PC4 assisted-p53-dependent apoptosis may play a central role. Thus, disruption of p53-PC4 interaction may be a good drug target for certain disease pathologies. A p53-derived short peptide (AcPep) that binds the C-terminal domain of PC4 (C-PC4) is known to disrupt PC4-p53 interaction. To fully characterize its binding mode and binding site on PC4, we co-crystallized C-PC4 with the peptide and determined its structure. The crystal, despite exhibiting mass spectrometric signature of the peptide, lacked peptide electron density and showed a novel crystal lattice, when compared to C-PC4 crystals without the peptide. Using peptide-docked models of crystal lattices, corresponding to our structure and the peptide-devoid structure we show the origin of the novel crystal lattice to be dynamically bound peptide at the previously identified putative binding site. The weak binding is proposed to be due to the lack of the N-terminal domain of PC4 (N-PC4), which we experimentally show to be disordered with no effect on PC4 stability. Taking cue from the structure, virtual screening of ∼18.6 million small molecules from the ZINC15 database was performed, followed by toxicity and binding free energy filtering. The novel crystal lattice of C-PC4 in presence of the peptide, the role of the disordered N-PC4 and the high throughput identification of potent small molecules will allow a better understanding and control of p53-PC4 interaction.
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Affiliation(s)
- Bhawna Pandey
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Aditya Dev
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Debamitra Chakravorty
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | | | - Smarajit Polley
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Siddhartha Roy
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Gautam Basu
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India.
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7
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On the specificity of protein-protein interactions in the context of disorder. Biochem J 2021; 478:2035-2050. [PMID: 34101805 PMCID: PMC8203207 DOI: 10.1042/bcj20200828] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 02/07/2023]
Abstract
With the increased focus on intrinsically disordered proteins (IDPs) and their large interactomes, the question about their specificity — or more so on their multispecificity — arise. Here we recapitulate how specificity and multispecificity are quantified and address through examples if IDPs in this respect differ from globular proteins. The conclusion is that quantitatively, globular proteins and IDPs are similar when it comes to specificity. However, compared with globular proteins, IDPs have larger interactome sizes, a phenomenon that is further enabled by their flexibility, repetitive binding motifs and propensity to adapt to different binding partners. For IDPs, this adaptability, interactome size and a higher degree of multivalency opens for new interaction mechanisms such as facilitated exchange through trimer formation and ultra-sensitivity via threshold effects and ensemble redistribution. IDPs and their interactions, thus, do not compromise the definition of specificity. Instead, it is the sheer size of their interactomes that complicates its calculation. More importantly, it is this size that challenges how we conceptually envision, interpret and speak about their specificity.
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8
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Ochiai K, Yamaoka M, Swaminathan A, Shima H, Hiura H, Matsumoto M, Kurotaki D, Nakabayashi J, Funayama R, Nakayama K, Arima T, Ikawa T, Tamura T, Sciammas R, Bouvet P, Kundu TK, Igarashi K. Chromatin Protein PC4 Orchestrates B Cell Differentiation by Collaborating with IKAROS and IRF4. Cell Rep 2020; 33:108517. [PMID: 33357426 DOI: 10.1016/j.celrep.2020.108517] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/10/2020] [Accepted: 11/22/2020] [Indexed: 12/24/2022] Open
Abstract
The chromatin protein positive coactivator 4 (PC4) has multiple functions, including chromatin compaction. However, its role in immune cells is largely unknown. We show that PC4 orchestrates chromatin structure and gene expression in mature B cells. B-cell-specific PC4-deficient mice show impaired production of antibody upon antigen stimulation. The PC4 complex purified from B cells contains the transcription factors (TFs) IKAROS and IRF4. IKAROS protein is reduced in PC4-deficient mature B cells, resulting in de-repression of their target genes in part by diminished interactions with gene-silencing components. Upon activation, the amount of IRF4 protein is not increased in PC4-deficient B cells, resulting in reduction of plasma cells. Importantly, IRF4 reciprocally induces PC4 expression via a super-enhancer. PC4 knockdown in human B cell lymphoma and myeloma cells reduces IKAROS protein as an anticancer drug, lenalidomide. Our findings establish PC4 as a chromatin regulator of B cells and a possible therapeutic target adjoining IKAROS in B cell malignancies.
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Affiliation(s)
- Kyoko Ochiai
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan.
| | - Mari Yamaoka
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan
| | - Amrutha Swaminathan
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Hiroki Shima
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan
| | - Hitoshi Hiura
- Department of Informative Genetics, Environment and Genome Research Center, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan
| | - Mitsuyo Matsumoto
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan; Center for Regulatory Epigenome and Diseases, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan
| | - Daisuke Kurotaki
- Department of Immunology, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Yokohama 236-0004, Japan
| | - Jun Nakabayashi
- Advanced Medical Research Center, Yokohama City University, Fukuura 3-9, Yokohama 236-0004, Japan
| | - Ryo Funayama
- Center for Regulatory Epigenome and Diseases, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan; Division of Cell Proliferation, United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan
| | - Keiko Nakayama
- Center for Regulatory Epigenome and Diseases, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan; Division of Cell Proliferation, United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan
| | - Takahiro Arima
- Department of Informative Genetics, Environment and Genome Research Center, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan
| | - Tomokatsu Ikawa
- Division of Immunobiology, Tokyo University of Science, Yamazaki 2669, Noda 278-0022, Japan
| | - Tomohiko Tamura
- Department of Immunology, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Yokohama 236-0004, Japan; Advanced Medical Research Center, Yokohama City University, Fukuura 3-9, Yokohama 236-0004, Japan
| | - Roger Sciammas
- Center for Immunology and Infectious Diseases, University of California Davis, Davis, CA 95616, USA
| | - Philippe Bouvet
- Université de Lyon, Ecole Normale Supérieure de Lyon, Centre de Recherche en Cancérologie de Lyon, Cancer Cell Plasticity Department, UMR INSERM 1052 CNRS 5286, Centre Léon Bérard, Lyon, France
| | - Tapas K Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
| | - Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan; Center for Regulatory Epigenome and Diseases, Tohoku University Graduate School of Medicine, Seiryo-machi 2-1, Sendai 980-8575, Japan.
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9
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Sikder S, Kaypee S, Kundu TK. Regulation of epigenetic state by non-histone chromatin proteins and transcription factors: Implications in disease. J Biosci 2020. [DOI: 10.1007/s12038-019-9974-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Vickers TA, Migawa MT, Seth PP, Crooke ST. Interaction of ASOs with PC4 Is Highly Influenced by the Cellular Environment and ASO Chemistry. J Am Chem Soc 2020; 142:9661-9674. [PMID: 32374993 DOI: 10.1021/jacs.0c01808] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The activity of PS-ASOs is strongly influenced by association with both inter- and intracellular proteins. The sequence, chemical nature, and structure of the ASO can have profound influences on the interaction of PS-ASOs with specific proteins. A more thorough understanding of how these pharmacological agents interact with various proteins and how chemical modifications, sequence, and structure influence interactions with proteins is needed to inform future ASO design efforts. To better understand the chemistry of PS-ASO interactions, we have focused on human positive cofactor 4 (PC4). Although several studies have investigated the in vitro binding properties of PC4 with endogenous nucleic acids, little is known about the chemistry of interaction of PS-ASOs with this protein. Here we examine in detail the impact of ASO backbone chemistry, 2'-modifications, and buffer environment on the binding affinity of PC4. In addition, using site-directed mutagenesis, we identify those amino acids that are specifically required for ASO binding interactions, and by substitution of abasic nucleotides we identify the positions on the ASO that most strongly influence affinity for PC4. Finally, to confirm that the interactions observed in vitro are biologically relevant, we use a recently developed complementation reporter system to evaluate the kinetics and subcellular localization of the interaction of ASO and PC4 in live cells.
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Affiliation(s)
- Timothy A Vickers
- Department of Core Antisense Research, IONIS Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, California 92010, United States
| | - Michael T Migawa
- Department of Medicinal ChemistryIONIS Pharmaceuticals, Inc.2855 Gazelle CourtCarlsbadCalifornia92010United States
| | - Punit P Seth
- Department of Medicinal ChemistryIONIS Pharmaceuticals, Inc.2855 Gazelle CourtCarlsbadCalifornia92010United States
| | - Stanley T Crooke
- Department of Core Antisense Research, IONIS Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, California 92010, United States
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11
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Efficacy of a small molecule inhibitor of the transcriptional cofactor PC4 in prevention and treatment of non-small cell lung cancer. PLoS One 2020; 15:e0230670. [PMID: 32231397 PMCID: PMC7108703 DOI: 10.1371/journal.pone.0230670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 03/05/2020] [Indexed: 12/19/2022] Open
Abstract
The human positive coactivator 4 (PC4) was originally identified as a multi-functional cofactor capable of mediating transcription activation by diverse gene- and tissue-specific activators. Recent studies suggest that PC4 might also function as a novel cancer biomarker and therapeutic target for different types of cancers. siRNA knockdown studies indicated that down-regulation of PC4 expression could inhibit tumorigeneicity of A549 non-small cell lung cancer tumor model in nude mice. Here we show that AG-1031, a small molecule identified by high throughput screening, can inhibit the double-stranded DNA binding activity of PC4, more effectively than its single-stranded DNA binding activity. AG-1031 also specifically inhibited PC4-dependent transcriptional activation in vitro using purified transcription factors. AG-1031 inhibited proliferation of several cultured cell lines derived from non-small cell lung cancers (NSCLC) and growth of tumors that formed from A549 cell xenografts in immuno-compromised mice. Moreover, pre-injection of AG-1031 in these mice not only reduced tumor size, but also prevented tumor formation in 20% of the animals. AG-1031 treated A549 cells and tumors from AG-1031 treated animals showed a significant decrease in the levels of both PC4 and VEGFC, a key mediator of angiogenesis in cancer. On the other hand, all tested mice remained constant weight during animal trials. These results demonstrated that AG-1031 could be a potential therapy for PC4-positive NSCLC.
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12
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Chen CY, Chen CC, Chuang WY, Leu YL, Ueng SH, Hsueh C, Yeh CT, Wang TH. Hydroxygenkwanin Inhibits Class I HDAC Expression and Synergistically Enhances the Antitumor Activity of Sorafenib in Liver Cancer Cells. Front Oncol 2020; 10:216. [PMID: 32158695 PMCID: PMC7052045 DOI: 10.3389/fonc.2020.00216] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 02/07/2020] [Indexed: 12/13/2022] Open
Abstract
Abnormal histone deacetylase (HDAC) expression is closely related to cancer development and progression. Many HDAC inhibitors have been widely used in cancer treatment; however, severe side effects often limit their clinical application. In this study, we attempted to identify natural compounds with HDAC inhibitory activity and low physiological toxicity and explored their feasibility and mechanisms of action in liver cancer treatment. A yeast screening system was used to identify natural compounds with HDAC inhibitory activity. Further, western blotting was used to verify inhibitory effects on HDAC in human liver cancer cell lines. Cell functional analysis was used to explore the effects and mechanisms and the in vitro results were verified in BALB/c nude mice. We found that hydroxygenkwanin (HGK), an extract from Daphne genkwa, inhibited class I HDAC expression, and thereby induced expression of tumor suppressor p21 and promoted acetylation and activation of p53 and p65. This resulted in the inhibition of growth, migration, and invasion of liver cancer cells and promoted cell apoptosis. Animal models revealed that HGK inhibited tumor growth in a synergistic manner with sorafenib. HGK inhibited class I HDAC expression and had low physiological toxicity. It has great potential as an adjuvant for liver cancer treatment and may be used in combination with anticancer drugs like sorafenib to improve therapeutic efficacy.
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Affiliation(s)
- Chi-Yuan Chen
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Research Center for Chinese Herbal Medicine, Graduate Institute of Health Industry Technology and Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Chin-Chuan Chen
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Wen-Yu Chuang
- Department of Anatomic Pathology, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan, Taiwan
| | - Yann-Lii Leu
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan.,Chinese Herbal Medicine Research Team, Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan.,Center for Traditional Chinese Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shir-Hwa Ueng
- Department of Anatomic Pathology, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan, Taiwan
| | - Chuen Hsueh
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Anatomic Pathology, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan, Taiwan
| | - Chau-Ting Yeh
- Department of Hepato-Gastroenterology, Liver Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Tong-Hong Wang
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Research Center for Chinese Herbal Medicine, Graduate Institute of Health Industry Technology and Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.,Department of Hepato-Gastroenterology, Liver Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
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13
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Sikder S, Kaypee S, Kundu TK. Regulation of epigenetic state by non-histone chromatin proteins and transcription factors: Implications in disease. J Biosci 2020; 45:15. [PMID: 31965993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Besides the fundamental components of the chromatin, DNA and octameric histone, the non-histone chromatin proteins and non-coding RNA play a critical role in the organization of functional chromatin domains. The non-histone chromatin proteins therefore regulate the transcriptional outcome in both physiological and pathophysiological state as well. They also help to maintain the epigenetic state of the genome indirectly. Several transcription factors and histone interacting factors also contribute in the maintenance of the epigenetic states, especially acetylation by the induction of autoacetylation ability of p300/CBP. Alterations of KAT activity have been found to be causally related to disease manifestation, and thus could be potential therapeutic target.
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Affiliation(s)
- Sweta Sikder
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560 064, India
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14
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Sikder S, Kumari S, Kumar M, Sen S, Singhal NB, Chellappan S, Godbole M, Chandrani P, Dutt A, Gopinath KS, Kundu TK. Chromatin protein PC4 is downregulated in breast cancer to promote disease progression: Implications of miR-29a. Oncotarget 2019; 10:6855-6869. [PMID: 31839879 PMCID: PMC6901337 DOI: 10.18632/oncotarget.27325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/19/2019] [Indexed: 02/05/2023] Open
Abstract
The human transcriptional coactivator PC4 has numerous roles to play in the cell. Other than its transcriptional coactivation function, it facilitates chromatin organization, DNA damage repair, viral DNA replication, etc. Although it was found to be an essential protein in vivo, the importance of this multifunctional protein in the regulation of different cellular pathways has not been investigated in details, particularly in oncogenesis. In this study, PC4 downregulation was observed in a significant proportion of mammary tissues obtained from Breast cancer patient samples as well as in a subset of highly invasive and metastatic Breast cancer patient-derived cell lines. We have identified a miRNA, miR-29a which potentially reduce the expression of PC4 both in RNA and protein level. This miR-29a was found to be indeed overexpressed in a substantial number of Breast cancer patient samples and cell lines as well, suggesting one of the key mechanisms of PC4 downregulation. Stable Knockdown of PC4 in MCF7 cells induced its migratory as well as invasive properties. Furthermore, in an orthotopic breast cancer mice model system; we have shown that reduced expression of PC4 enhances the tumorigenic potential substantially. Absence of PC4 led to the upregulation of several genes involved in Epithelial to Mesenchymal Transition (EMT), indicating the possible mechanism of uniform tumour progression in the orthotropic mice. Collectively these data establish the role of PC4 in tumour suppression.
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Affiliation(s)
- Sweta Sikder
- 1Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Sujata Kumari
- 1Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Manoj Kumar
- 1Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Shrinka Sen
- 1Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | | | | | - Mukul Godbole
- 3Integrated Cancer Genomics Lab, Advanced Centre for Treatment, Research and Education in Cancer, Mumbai, India
| | - Pratik Chandrani
- 3Integrated Cancer Genomics Lab, Advanced Centre for Treatment, Research and Education in Cancer, Mumbai, India
| | - Amit Dutt
- 3Integrated Cancer Genomics Lab, Advanced Centre for Treatment, Research and Education in Cancer, Mumbai, India
| | | | - Tapas K. Kundu
- 1Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
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15
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Mondal P, Saleem S, Sikder S, Kundu TK, Biswas SC, Roy S. Multifunctional transcriptional coactivator PC4 is a global co-regulator of p53-dependent stress response and gene regulation. J Biochem 2019; 166:403-413. [PMID: 31236588 DOI: 10.1093/jb/mvz050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 06/19/2019] [Indexed: 01/26/2023] Open
Abstract
Human positive coactivator 4 (PC4), a multifunctional chromatin-associated protein, is known to directly interact with p53 and modulate expressions of a few p53-dependent genes. However, the role of PC4 in p53's myriad of other regulatory functions is not known. The p53-PC4 interaction was selectively perturbed by a small peptide which led to abrogation of genotoxic stress-induced up-regulation of many p53-dependent genes and reduction of apoptosis in A549 cells. Over-expression of a PC4 point mutant, incapable of binding p53, recapitulated many of the effects of the peptide. Global gene expression profiling in A549 cells, upon peptide treatment, revealed PC4's involvement in the regulation of many p53-dependent pathways, including the Hippo pathway. Introduction of the peptide in neuronal cells significantly reduced its amyloid-β-induced death. Thus, PC4 emerges as a global co-regulator of p53 and a therapeutic target against pathogeneses where the p53-dependent cell death process plays a crucial role.
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Affiliation(s)
- Priya Mondal
- Department of Biophysics, Bose Institute, P1/12, CIT Scheme VIIM, Kolkata, West Bengal
| | - Suraiya Saleem
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, West Bengal
| | - Sweta Sikder
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Tapas K Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Subhas Chandra Biswas
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, West Bengal
| | - Siddhartha Roy
- Department of Biophysics, Bose Institute, P1/12, CIT Scheme VIIM, Kolkata, West Bengal
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16
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Megger DA, Abou-Eid S, Zülch B, Sitek B. Systematic analysis of synergistic proteome modulations in a drug combination of cisplatin and MLN4924. Mol Omics 2019; 14:450-457. [PMID: 30255909 DOI: 10.1039/c8mo00115d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chemotherapeutic treatment regimens often take advantage of synergistic effects of drug combinations. Anticipating that synergistic effects on the cell biological level likely manifest on the proteome level, the analysis of proteome modulations represents an appropriate strategy to study drug combinations on a molecular level. More specifically, the detection of single proteins exhibiting synergistic abundance changes could be helpful to shed light on key molecules, which contribute in mechanisms facilitating the synergistic interaction and therefore represent potential targets for specific therapeutic approaches. In the reported study we aimed to provide evidence for this assumption and investigated the drug combination of cisplatin and the neddylation inhibitor MLN4924 in HCT-116 cells via cell biological analyses and mass spectrometry-based quantitative proteomics. From 1789 proteins quantified with two unique peptides, activated RNA polymerase II transcriptional coactivator p15 (SUB1) was highlighted as the most synergistically regulated protein using a synergistic scoring approach. Western blotting and analyses of cellular processes associated with this protein (DNA damage, oxidative stress and apoptosis) revealed supporting evidence for the synergistic regulation. Whereas the distinct role of SUB1 in the investigated drug combination needs to be elucidated in future studies, the presented results demonstrated the benefit and feasibility of synergistic scoring of proteome alterations to highlight proteins that likely contribute to the underlying molecular mechanisms of synergistic effects. Data are available via ProteomeXchange with identifier PXD009185.
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Affiliation(s)
- Dominik Andre Megger
- Medizinisches Proteom-Center, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
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17
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Interaction of positive coactivator 4 with histone 3.3 protein is essential for transcriptional activation of the luteinizing hormone receptor gene. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:971-981. [PMID: 30496042 DOI: 10.1016/j.bbagrm.2018.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 11/23/2022]
Abstract
The luteinizing hormone receptor (LHR) is essential for sexual development and reproduction in mammals. We have established that Sp1 has a central role in derepression of LHR gene transcription induced by Trichostatin A (TSA) in MCF7 cells. Moreover, the co-activator PC4 which associates directly with Sp1 at the LHR promoter is essential for TSA-mediated LHR transcription. This study explores interactions of PC4 with histone proteins, which presumably triggers chromatin modifications during LHR transcriptional activation. TSA treatment of MCF7 cells expressing PC4-Flag protein induces acetylation of histone 3 (H3) and immunoprecipitation (IP) studies revealed its interaction with PC4-Flag protein. MS/MS analysis of the protein complex obtained after IP from TSA treated samples detected H3.3 acetylated at K9, K14, K18, K23 and K27 as a PC4 interacting protein. The association of PC4 with H3.3 was corroborated by IP and re-ChIP using H3.3 antibody. Similarly, IP and re-ChIP showed association of PC4 with H3 acetylated protein. Knockdown of PC4 in MCF7 cells reduced H3.3 enrichment, H3 acetylation at the Lys sites and LHR promoter activity in TSA treated cells despite an increase in H3 and H3.3 protein induced by TSA, linking PC4 to H3 acetylation and LHR transcription. Depletion of H3.3 A/B in MCF7 cells impair chromatin accessibility and enrichment of Pol II and TFIIB at the LHR promoter and its activation, resulting in marked reduction of LHR gene expression. Together, these findings point to the critical role of PC4 and its association with acetylated H3.3 in TSA-induced LHR gene transcription.
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18
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Shanmugam MK, Arfuso F, Arumugam S, Chinnathambi A, Jinsong B, Warrier S, Wang LZ, Kumar AP, Ahn KS, Sethi G, Lakshmanan M. Role of novel histone modifications in cancer. Oncotarget 2018; 9:11414-11426. [PMID: 29541423 PMCID: PMC5834259 DOI: 10.18632/oncotarget.23356] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/01/2017] [Indexed: 01/02/2023] Open
Abstract
Oncogenesis is a multistep process mediated by a variety of factors including epigenetic modifications. Global epigenetic post-translational modifications have been detected in almost all cancers types. Epigenetic changes appear briefly and do not involve permanent changes to the primary DNA sequence. These epigenetic modifications occur in key oncogenes, tumor suppressor genes, and transcription factors, leading to cancer initiation and progression. The most commonly observed epigenetic changes include DNA methylation, histone lysine methylation and demethylation, histone lysine acetylation and deacetylation. However, there are several other novel post-translational modifications that have been observed in recent times such as neddylation, sumoylation, glycosylation, phosphorylation, poly-ADP ribosylation, ubiquitination as well as transcriptional regulation and these have been briefly discussed in this article. We have also highlighted the diverse epigenetic changes that occur during the process of tumorigenesis and described the role of histone modifications that can occur on tumor suppressor genes as well as oncogenes, which regulate tumorigenesis and can thus form the basis of novel strategies for cancer therapy.
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Affiliation(s)
- Muthu K. Shanmugam
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Frank Arfuso
- Stem Cell and Cancer Biology Laboratory, School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Surendar Arumugam
- Institute of Molecular and Cell Biology, A*STAR, Biopolis Drive, Proteos, Singapore, Singapore
| | - Arunachalam Chinnathambi
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Bian Jinsong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sudha Warrier
- Division of Cancer Stem Cells and Cardiovascular Regeneration, School of Regenerative Medicine, Manipal Academy of Higher Education (MAHE), Bangalore, India
| | - Ling Zhi Wang
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Alan Prem Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Perth, WA, Australia
- National University Cancer Institute, National University Health System, Singapore, Singapore
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Kwang Seok Ahn
- College of Korean Medicine, Kyung Hee University, Dongdaemun-gu, Seoul, Korea
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Manikandan Lakshmanan
- Institute of Molecular and Cell Biology, A*STAR, Biopolis Drive, Proteos, Singapore, Singapore
- Department of Pathology, National University Hospital Singapore, Singapore, Singapore
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19
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Sub1/PC4, a multifaceted factor: from transcription to genome stability. Curr Genet 2017; 63:1023-1035. [DOI: 10.1007/s00294-017-0715-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 05/24/2017] [Accepted: 05/26/2017] [Indexed: 10/19/2022]
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20
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Griffin WC, Gao J, Byrd AK, Chib S, Raney KD. A biochemical and biophysical model of G-quadruplex DNA recognition by positive coactivator of transcription 4. J Biol Chem 2017; 292:9567-9582. [PMID: 28416612 DOI: 10.1074/jbc.m117.776211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/14/2017] [Indexed: 12/22/2022] Open
Abstract
DNA sequences that are guanine-rich have received considerable attention because of their potential to fold into a secondary, four-stranded DNA structure termed G-quadruplex (G4), which has been implicated in genomic instability and some human diseases. We have previously identified positive coactivator of transcription (PC4), a single-stranded DNA (ssDNA)-binding protein, as a novel G4 interactor. Here, to expand on these previous observations, we biochemically and biophysically characterized the interaction between PC4 and G4DNA. PC4 can bind alternative G4DNA topologies with a low nanomolar Kd value of ∼2 nm, similar to that observed for ssDNA. In consideration of the different structural features between G4DNA and ssDNA, these binding data indicated that PC4 can interact with G4DNA in a manner distinct from ssDNA. The stoichiometry of the PC4-G4 complex was 1:1 for PC4 dimer:G4 substrate. PC4 did not enhance the rate of folding of G4DNA, and formation of the PC4-G4DNA complex did not result in unfolding of the G4DNA structure. We assembled a G4DNA structure flanked by duplex DNA. We find that PC4 can interact with this G4DNA, as well as the complementary C-rich strand. Molecular docking simulations and DNA footprinting experiments suggest a model where a PC4 dimer accommodates the DNA with one monomer on the G4 strand and the second monomer bound to the C-rich strand. Collectively, these data provide a novel mode of PC4 binding to a DNA secondary structure that remains within the framework of the model for binding to ssDNA. Additionally, consideration of the PC4-G4DNA interaction could provide insight into the biological functions of PC4, which remain incompletely understood.
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Affiliation(s)
- Wezley C Griffin
- From the Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7101
| | - Jun Gao
- From the Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7101
| | - Alicia K Byrd
- From the Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7101
| | - Shubeena Chib
- From the Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7101
| | - Kevin D Raney
- From the Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205-7101
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21
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Caldwell RB, Braselmann H, Schoetz U, Heuer S, Scherthan H, Zitzelsberger H. Positive Cofactor 4 (PC4) is critical for DNA repair pathway re-routing in DT40 cells. Sci Rep 2016; 6:28890. [PMID: 27374870 PMCID: PMC4931448 DOI: 10.1038/srep28890] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 06/09/2016] [Indexed: 01/06/2023] Open
Abstract
PC4 is an abundant single-strand DNA binding protein that has been implicated in transcription and DNA repair. Here, we show that PC4 is involved in the cellular DNA damage response. To elucidate the role, we used the DT40 chicken B cell model, which produces clustered DNA lesions at Ig loci via the action of activation-induced deaminase. Our results help resolve key aspects of immunoglobulin diversification and suggest an essential role of PC4 in repair pathway choice. We show that PC4 ablation in gene conversion (GC)-active cells significantly disrupts GC but has little to no effect on targeted homologous recombination. In agreement, the global double-strand break repair response, as measured by γH2AX foci analysis, is unperturbed 16 hours post irradiation. In cells with the pseudo-genes removed (GC inactive), PC4 ablation reduced the overall mutation rate while simultaneously increasing the transversion mutation ratio. By tagging the N-terminus of PC4, gene conversion and somatic hypermutation are all but abolished even when native non-tagged PC4 is present, indicating a dominant negative effect. Our data point to a very early and deterministic role for PC4 in DNA repair pathway re-routing.
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Affiliation(s)
- Randolph B Caldwell
- Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH). Department of Radiation Sciences - Research Unit Radiation Cytogenetics, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Herbert Braselmann
- Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH). Department of Radiation Sciences - Research Unit Radiation Cytogenetics, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Ulrike Schoetz
- Clinical Cooperation Group 'Personalized Radiotherapy of Head and Neck Cancer', Helmholtz Zentrum München, Ingolstaedter Landstr 1, 85764, Neuherberg, Germany.,Department of Radiotherapy and Radiation Oncology, Ludwig-Maximilians-University Munich, Marchioninistr 15, 81377, Munich, Germany
| | - Steffen Heuer
- Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH). Department of Radiation Sciences - Research Unit Radiation Cytogenetics, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Harry Scherthan
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm. Neuherbergstr. 11, 80937 Muenchen, Germany
| | - Horst Zitzelsberger
- Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH). Department of Radiation Sciences - Research Unit Radiation Cytogenetics, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.,Clinical Cooperation Group 'Personalized Radiotherapy of Head and Neck Cancer', Helmholtz Zentrum München, Ingolstaedter Landstr 1, 85764, Neuherberg, Germany
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22
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Chakravarthi BVSK, Goswami MT, Pathi SS, Robinson AD, Cieślik M, Chandrashekar DS, Agarwal S, Siddiqui J, Daignault S, Carskadon SL, Jing X, Chinnaiyan AM, Kunju LP, Palanisamy N, Varambally S. MicroRNA-101 regulated transcriptional modulator SUB1 plays a role in prostate cancer. Oncogene 2016; 35:6330-6340. [PMID: 27270442 PMCID: PMC5140777 DOI: 10.1038/onc.2016.164] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/30/2016] [Accepted: 04/06/2016] [Indexed: 12/20/2022]
Abstract
MicroRNA-101, a tumor suppressor microRNA (miR), is often downregulated in cancer and is known to target multiple oncogenes. Some of the genes that are negatively regulated by miR-101 expression include histone methyltransferase EZH2 (enhancer of zeste homolog 2), COX2 (cyclooxygenase-2), POMP (proteasome maturation protein), CERS6, STMN1, MCL-1 and ROCK2, among others. In the present study, we show that miR-101 targets transcriptional coactivator SUB1 homolog (Saccharomyces cerevisiae)/PC4 (positive cofactor 4) and regulates its expression. SUB1 is known to have diverse role in vital cell processes such as DNA replication, repair and heterochromatinization. SUB1 is known to modulate transcription and acts as a mediator between the upstream activators and general transcription machinery. Expression profiling in several cancers revealed SUB1 overexpression, suggesting a potential role in tumorigenesis. However, detailed regulation and function of SUB1 has not been elucidated. In this study, we show elevated expression of SUB1 in aggressive prostate cancer. Knockdown of SUB1 in prostate cancer cells resulted in reduced cell proliferation, invasion and migration in vitro, and tumor growth and metastasis in vivo. Gene expression analyses coupled with chromatin immunoprecipitation revealed that SUB1 binds to the promoter regions of several oncogenes such as PLK1 (Polo-like kinase 1), C-MYC, serine-threonine kinase BUB1B and regulates their expression. Additionally, we observed SUB1 downregulated CDKN1B expression. PLK1 knockdown or use of PLK1 inhibitor can mitigate oncogenic function of SUB1 in benign prostate cancer cells. Thus, our study suggests that miR-101 loss results in increased SUB1 expression and subsequent activation of known oncogenes driving prostate cancer progression and metastasis. This study therefore demonstrates functional role of SUB1 in prostate cancer, and identifies its regulation and potential downstream therapeutic targets of SUB1 in prostate cancer.
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Affiliation(s)
- B V S K Chakravarthi
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA.,Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - M T Goswami
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - S S Pathi
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - A D Robinson
- Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - M Cieślik
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - D S Chandrashekar
- Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - S Agarwal
- Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - J Siddiqui
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - S Daignault
- Center for Cancer Biostatistics, Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - S L Carskadon
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - X Jing
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - A M Chinnaiyan
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Urology, University of Michigan, Ann Arbor, MI, USA.,Howard Hughes Medical Institute, University of Michigan Medical School, Ann Arbor, MI, USA.,Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA
| | - L P Kunju
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - N Palanisamy
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA.,Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA
| | - S Varambally
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA.,Department of Pathology, University of Michigan, Ann Arbor, MI, USA.,Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.,Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA.,Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
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23
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Dhanasekaran K, Kumari S, Boopathi R, Shima H, Swaminathan A, Bachu M, Ranga U, Igarashi K, Kundu TK. Multifunctional human transcriptional coactivator protein PC4 is a substrate of Aurora kinases and activates the Aurora enzymes. FEBS J 2016; 283:968-85. [DOI: 10.1111/febs.13653] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/24/2015] [Accepted: 01/11/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Karthigeyan Dhanasekaran
- Transcription and Disease Laboratory; Molecular Biology and Genetics Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore Karnataka India
| | - Sujata Kumari
- Transcription and Disease Laboratory; Molecular Biology and Genetics Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore Karnataka India
| | - Ramachandran Boopathi
- Transcription and Disease Laboratory; Molecular Biology and Genetics Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore Karnataka India
| | - Hiroki Shima
- Department of Biochemistry; Tohoku University Graduate School of Medicine; Sendai Japan
- Center for Regulatory Epigenome and Diseases; Tohoku University; Sendai Japan
- CREST; Japan Science and Technology Agency; Sendai Japan
| | - Amrutha Swaminathan
- Transcription and Disease Laboratory; Molecular Biology and Genetics Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore Karnataka India
| | - Mahesh Bachu
- Molecular Virology Laboratory; Molecular Biology and Genetics Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore Karnataka India
| | - Udaykumar Ranga
- Molecular Virology Laboratory; Molecular Biology and Genetics Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore Karnataka India
| | - Kazuhiko Igarashi
- Department of Biochemistry; Tohoku University Graduate School of Medicine; Sendai Japan
- Center for Regulatory Epigenome and Diseases; Tohoku University; Sendai Japan
- CREST; Japan Science and Technology Agency; Sendai Japan
| | - Tapas K. Kundu
- Transcription and Disease Laboratory; Molecular Biology and Genetics Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Bangalore Karnataka India
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24
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Wang X, Xu J, Liu C, Chen Y. Specific interaction of platinated DNA and proteins by surface plasmon resonance imaging. RSC Adv 2016. [DOI: 10.1039/c5ra27719a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A surface plasmon resonance imaging method to differentiate the interaction between the protein human high mobility group box 1 or human nuclear protein positive cofactor 4 (PC4) and DNAs has been developed.
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Affiliation(s)
- Xiao Wang
- Key Laboratory of Analytical Chemistry for Living Biosystems
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Jiying Xu
- Key Laboratory of Analytical Chemistry for Living Biosystems
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Chanjuan Liu
- Key Laboratory of Analytical Chemistry for Living Biosystems
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Yi Chen
- Key Laboratory of Analytical Chemistry for Living Biosystems
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
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Aubry A, Galiacy S, Ceccato L, Marchand C, Tricoire C, Lopez F, Bremner R, Racaud-Sultan C, Monsarrat B, Malecaze F, Allouche M. Peptides derived from the dependence receptor ALK are proapoptotic for ALK-positive tumors. Cell Death Dis 2015; 6:e1736. [PMID: 25950466 PMCID: PMC4669685 DOI: 10.1038/cddis.2015.102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 02/20/2015] [Accepted: 02/24/2015] [Indexed: 01/03/2023]
Abstract
ALK is a receptor tyrosine kinase with an oncogenic role in various types of human malignancies. Despite constitutive activation of the kinase through gene alterations, such as chromosomal translocation, gene amplification or mutation, treatments with kinase inhibitors invariably lead to the development of resistance. Aiming to develop new tools for ALK targeting, we took advantage of our previous demonstration identifying ALK as a dependence receptor, implying that in the absence of ligand the kinase-inactive ALK triggers or enhances apoptosis. Here, we synthesized peptides mimicking the proapoptotic domain of ALK and investigated their biological effects on tumor cells. We found that an ALK-derived peptide of 36 amino acids (P36) was cytotoxic for ALK-positive anaplastic large-cell lymphoma and neuroblastoma cell lines. In contrast, ALK-negative tumor cells and normal peripheral blood mononuclear cells were insensitive to P36. The cytotoxic effect was due to caspase-dependent apoptosis and required N-myristoylation of the peptide. Two P36-derived shorter peptides as well as a cyclic peptide also induced apoptosis. Surface plasmon resonance and mass spectrometry analysis of P36-interacting proteins from two responsive cell lines, Cost lymphoma and SH-SY5Y neuroblastoma, uncovered partners that could involve p53-dependent signaling and pre-mRNA splicing. Furthermore, siRNA-mediated knockdown of p53 rescued these cells from P36-induced apoptosis. Finally, we observed that a treatment combining P36 with the ALK-specific inhibitor crizotinib resulted in additive cytotoxicity. Therefore, ALK-derived peptides could represent a novel targeted therapy for ALK-positive tumors.
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Affiliation(s)
- A Aubry
- 1] Université de Toulouse, UPS, EA4555, GR2DE, CPTP, Toulouse F-31300, France [2] Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, M5G 1X5, Canada [3] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, M5S 1A1, Canada
| | - S Galiacy
- 1] Université de Toulouse, UPS, EA4555, GR2DE, CPTP, Toulouse F-31300, France [2] CHU Purpan, Toulouse F-31300, France
| | - L Ceccato
- Université de Toulouse, UPS, EA4555, GR2DE, CPTP, Toulouse F-31300, France
| | - C Marchand
- Université de Toulouse, UPS, EA4555, GR2DE, CPTP, Toulouse F-31300, France
| | - C Tricoire
- Université de Toulouse, UPS, EA4555, GR2DE, CPTP, Toulouse F-31300, France
| | - F Lopez
- INSERM, UMR1037, CRCT, Toulouse F-31000, France
| | - R Bremner
- 1] Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, M5G 1X5, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, M5S 1A1, Canada
| | - C Racaud-Sultan
- 1] INSERM, UMR 1043, CPTP, Toulouse F-31300, France [2] CNRS, UMR 5282, CPTP, Toulouse F-31300, France
| | - B Monsarrat
- CNRS, UMR 5089, IPBS, Toulouse F-31077, France
| | - F Malecaze
- 1] Université de Toulouse, UPS, EA4555, GR2DE, CPTP, Toulouse F-31300, France [2] CHU Purpan, Toulouse F-31300, France
| | - M Allouche
- Université de Toulouse, UPS, EA4555, GR2DE, CPTP, Toulouse F-31300, France
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Chen L, Du C, Wang L, Yang C, Zhang JR, Li N, Li Y, Xie XD, Gao GD. Human positive coactivator 4 (PC4) is involved in the progression and prognosis of astrocytoma. J Neurol Sci 2014; 346:293-8. [DOI: 10.1016/j.jns.2014.09.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 08/17/2014] [Accepted: 09/12/2014] [Indexed: 02/02/2023]
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Mulvey CM, Tudzarova S, Crawford M, Williams GH, Stoeber K, Godovac-Zimmermann J. Subcellular proteomics reveals a role for nucleo-cytoplasmic trafficking at the DNA replication origin activation checkpoint. J Proteome Res 2013; 12:1436-53. [PMID: 23320540 PMCID: PMC4261602 DOI: 10.1021/pr3010919] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Depletion of DNA replication initiation factors such as CDC7 kinase triggers the origin activation checkpoint in healthy cells and leads to a protective cell cycle arrest at the G1 phase of the mitotic cell division cycle. This protective mechanism is thought to be defective in cancer cells. To investigate how this checkpoint is activated and maintained in healthy cells, we conducted a quantitative SILAC analysis of the nuclear- and cytoplasmic-enriched compartments of CDC7-depleted fibroblasts and compared them to a total cell lysate preparation. Substantial changes in total abundance and/or subcellular location were detected for 124 proteins, including many essential proteins associated with DNA replication/cell cycle. Similar changes in protein abundance and subcellular distribution were observed for various metabolic processes, including oxidative stress, iron metabolism, protein translation and the tricarboxylic acid cycle. This is accompanied by reduced abundance of two karyopherin proteins, suggestive of reduced nuclear import. We propose that altered nucleo-cytoplasmic trafficking plays a key role in the regulation of cell cycle arrest. The results increase understanding of the mechanisms underlying maintenance of the DNA replication origin activation checkpoint and are consistent with our proposal that cell cycle arrest is an actively maintained process that appears to be distributed over various subcellular locations.
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Affiliation(s)
- Claire M. Mulvey
- Division of Medicine, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Slavica Tudzarova
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Mark Crawford
- Division of Medicine, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Gareth H. Williams
- Research Department of Pathology and UCL Cancer Institute, Rockefeller Building, University College London, University Street, London WC1E 6JJ, United Kingdom
| | - Kai Stoeber
- Research Department of Pathology and UCL Cancer Institute, Rockefeller Building, University College London, University Street, London WC1E 6JJ, United Kingdom
| | - Jasminka Godovac-Zimmermann
- Division of Medicine, University College London, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom
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Peng Y, Yang J, Zhang E, Sun H, Wang Q, Wang T, Su Y, Shi C. Human positive coactivator 4 is a potential novel therapeutic target in non-small cell lung cancer. Cancer Gene Ther 2012; 19:690-6. [PMID: 22918472 DOI: 10.1038/cgt.2012.52] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Transcriptional positive coactivator 4 (PC4) is a multifunctional nuclear protein that has important roles in DNA transcription, replication, repair and heterochromatinization. However, the role of PC4 in cancer remains to be clarified. Several studies propose that PC4 may act as a putative tumor suppressor. Here, we demonstrate for the first time that PC4 may represent a potential therapeutic target in non-small cell lung cancer (NSCLC). PC4 protein expression is significantly upregulated in NSCLC carcinoma tissues compared with their adjacent noncancerous counterparts as shown by immunohistochemical staining and western blotting in 104 pairs of formalin-fixed human NSCLC specimens and 6 fresh NSCLC samples. Knockdown of PC4 expression by sequence-specific small interfering RNA (siRNA) in human NSCLC cells (A549, H460 and H358) significantly inhibits the growth of cancer cells by the induction of cell cycle arrest and the increase of cell apoptosis in vitro. Interrupting the PC4 signaling pathway by injection of the PC4 siRNA liposome complex produced an effective regression of pre-established A549 cell xenografts in mice through growth inhibition and increased apoptosis. These results indicated that PC4 could be an attractive new therapeutic target for the treatment of NSCLC.
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Affiliation(s)
- Y Peng
- Institute of Combined Injury, State Key Laboratory of Trauma, Burns and Combined Injury, Research Center of Nanomedicine, College of Preventive Medicine, Third Military Medical University, Chongqing, China
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Sub1 and RPA associate with RNA polymerase II at different stages of transcription. Mol Cell 2011; 44:397-409. [PMID: 22055186 DOI: 10.1016/j.molcel.2011.09.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 06/06/2011] [Accepted: 09/30/2011] [Indexed: 01/24/2023]
Abstract
Single-stranded DNA-binding proteins play many roles in nucleic acid metabolism, but their importance during transcription remains unclear. Quantitative proteomic analysis of RNA polymerase II (RNApII) preinitiation complexes (PICs) identified Sub1 and the replication protein A complex (RPA), both of which bind single-stranded DNA (ssDNA). Sub1, homolog of mammalian coactivator PC4, exhibits strong genetic interactions with factors necessary for promoter melting. Sub1 localizes near the transcription bubble in vitro and binds to promoters in vivo dependent upon PIC assembly. In contrast, RPA localizes to transcribed regions of active genes, strongly correlated with transcribing RNApII but independently of replication. RFA1 interacts genetically with transcription elongation factor genes. Interestingly, RPA levels increase at active promoters in cells carrying a Sub1 deletion or ssDNA-binding mutant, suggesting competition for a common binding site. We propose that Sub1 and RPA interact with the nontemplate strand of RNApII complexes during initiation and elongation, respectively.
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Zhang ZJ, Tong YQ, Wang JJ, Yang C, Zhou GH, Li YH, Xie PL, Hu JY, Li GC. Spaceflight alters the gene expression profile of cervical cancer cells. CHINESE JOURNAL OF CANCER 2011; 30:842-52. [PMID: 22098948 PMCID: PMC4013332 DOI: 10.5732/cjc.011.10174] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Our previous study revealed that spaceflight induced biological changes in human cervical carcinoma Caski cells. Here, we report that 48A9 cells, which were subcloned from Caski cells, experienced significant growth suppression and exhibited low tumorigenic ability after spaceflight. To further understand the potential mechanism at the transcriptional level, we compared gene expression between 48A9 cells and ground control Caski cells with suppression subtractive hybridization (SSH) and reverse Northern blotting methods, and analyzed the relative gene network and molecular functions with the Ingenuity Pathways Analysis (IPA) program. We found 5 genes, SUB1, SGEF, MALAT-1, MYL6, and MT-CO2, to be up-regulated and identified 3 new cDNAs, termed B4, B5, and C4, in 48A9 cells. In addition, we also identified the two most significant gene networks to indicate the function of these genes using the IPA program. To our knowledge, our results show for the first time that spaceflight can reduce the growth of tumor cells, and we also provide a new model for oncogenesis study.
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Affiliation(s)
- Zhi-Jie Zhang
- Xiangya School of Medicine, Central South University, Changsha, Hunan, People's Republic of China
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Debnath S, Chatterjee S, Arif M, Kundu TK, Roy S. Peptide-protein interactions suggest that acetylation of lysines 381 and 382 of p53 is important for positive coactivator 4-p53 interaction. J Biol Chem 2011; 286:25076-87. [PMID: 21586571 DOI: 10.1074/jbc.m110.205328] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human transcriptional positive coactivator 4 (PC4) activates several p53-dependent genes. It has been demonstrated that this is a consequence of direct interaction with p53. Previously, we have concluded that PC4 interacts mainly with the C-terminal negative regulatory domain of p53 through its DNA binding C-terminal half. NMR chemical shift perturbation studies with peptide fragments indicated that amino acids 380-386 of p53 are crucial for interaction with PC4. This was verified by fluorescence anisotropy and sedimentation velocity studies. A peptide consisting of p53-(380-386) sequence, when attached to a cell penetration tag and nuclear localization signal, localizes to the nucleus and inhibits luciferase gene expression from a transfected plasmid carrying a Luc gene under a p53-dependent promoter. Acetylation of lysine 382/381 enhanced the binding of this peptide to PC4 by about an order of magnitude. NMR and mutagenesis studies indicated that serine 73 of PC4 is an important residue for recognition of p53. Intermolecular nuclear Overhauser effect placed aspartate 76 in the vicinity of lysine 381, indicating that the region around residues 73-76 of PC4 is important for p53 recognition. We conclude that the 380-386 region of p53 interacts with the region around residues 73-76 of PC4, and acetylation of lysine 382/381 of p53 may play an important role in modulating p53-PC4 interaction and as a consequence PC4 mediated activation of p53 target genes.
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Affiliation(s)
- Subrata Debnath
- Division of Structural Biology and Bioinformatics, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research (India), 4, Raja S. C. Mullick Road, Kolkata 700032, India
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Liao M, Zhang Y, Kang JH, Dufau ML. Coactivator function of positive cofactor 4 (PC4) in Sp1-directed luteinizing hormone receptor (LHR) gene transcription. J Biol Chem 2010; 286:7681-91. [PMID: 21193408 DOI: 10.1074/jbc.m110.188532] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The LHR has an essential role in sexual development and reproductive function, and its transcription is subjected to several modes of regulation. In this study, we investigated PC4 coactivator function in the control of LHR transcription. Knockdown of PC4 by siRNA inhibited the LHR basal promoter activity and trichostatin A (TSA)-induced gene transcriptional activation and expression in MCF-7 cells. While overexpression of PC4 alone had no effect on the LHR gene, it significantly enhanced Sp1- but not Sp3-mediated LHR transcriptional activity. PC4 directly interacts with Sp1 at the LHR promoter, and this interaction is negatively regulated by PC4 phosphorylation. The coactivator domain (22-91 aa) of PC4 and DNA binding domain of Sp1 are essential for PC4/Sp1 interaction. ChIP assay revealed significant occupancy of PC4 at the LHR promoter that increased upon TSA treatment. Disruption of PC4 expression significantly reduced TSA-induced recruitment of TFIIB and RNAP II, at the promoter. PC4 functions are beyond TSA-induced phosphatase release, PI3K-mediated Sp1 phosphorylation, and HDAC1/2/mSin3A co-repressor release indicating its role as linker coactivator of Sp1 and the transcriptional machinery. These findings demonstrated a critical aspect of LHR modulation whereby PC4 acts as a coactivator of Sp1 to contribute to the human of LHR transcription.
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Affiliation(s)
- Mingjuan Liao
- Molecular Endocrinology Section, Program of Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4510, USA
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Arif M, Senapati P, Shandilya J, Kundu TK. Protein lysine acetylation in cellular function and its role in cancer manifestation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1799:702-16. [PMID: 20965294 DOI: 10.1016/j.bbagrm.2010.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 10/08/2010] [Accepted: 10/12/2010] [Indexed: 01/05/2023]
Abstract
Lysine acetylation appears to be crucial for diverse biological phenomena, including all the DNA-templated processes, metabolism, cytoskeleton dynamics, cell signaling, and circadian rhythm. A growing number of cellular proteins have now been identified to be acetylated and constitute the complex cellular acetylome. Cross-talk among protein acetylation together with other post-translational modifications fine-tune the cellular functions of different protein machineries. Dysfunction of acetylation process is often associated with several diseases, especially cancer. This review focuses on the recent advances in the role of protein lysine acetylation in diverse cellular functions and its implications in cancer manifestation.
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Affiliation(s)
- Mohammed Arif
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur (P.O.), Bangalore-560 064, Karnataka, India
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Meyer KD, Lin SC, Bernecky C, Gao Y, Taatjes DJ. p53 activates transcription by directing structural shifts in Mediator. Nat Struct Mol Biol 2010; 17:753-60. [PMID: 20453859 PMCID: PMC2932482 DOI: 10.1038/nsmb.1816] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 03/23/2010] [Indexed: 12/24/2022]
Abstract
It is not well understood how the human Mediator complex, transcription factor IIH and RNA polymerase II (Pol II) work together with activators to initiate transcription. Activator binding alters Mediator structure, yet the functional consequences of such structural shifts remain unknown. The p53 C terminus and its activation domain interact with different Mediator subunits, and we find that each interaction differentially affects Mediator structure; strikingly, distinct p53-Mediator structures differentially affect Pol II activity. Only the p53 activation domain induces the formation of a large pocket domain at the Mediator-Pol II interaction site, and this correlates with activation of stalled Pol II to a productively elongating state. Moreover, we define a Mediator requirement for TFIIH-dependent Pol II C-terminal domain phosphorylation and identify substantial differences in Pol II C-terminal domain processing that correspond to distinct p53-Mediator structural states. Our results define a fundamental mechanism by which p53 activates transcription and suggest that Mediator structural shifts trigger activation of stalled Pol II complexes.
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Affiliation(s)
- Krista D Meyer
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, USA
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Abstract
Inactivation of p53 is critical for the formation of most tumors. Illumination of the key function(s) of p53 protein in protecting cells from becoming cancerous is therefore a worthy goal. Arguably p53's most important function is to act as a transcription factor that directly regulates perhaps several hundred of the cell's RNA polymerase II (RNAP II)-transcribed genes, and indirectly regulates thousands of others. Indeed p53 is the most well studied mammalian transcription factor. The p53 tetramer binds to its response element where it can recruit diverse transcriptional coregulators such as histone modifying enzymes, chromatin remodeling factors, subunits of the mediator complex, and components of general transcription machinery and preinitiation complex (PIC) to modulate RNAPII activity at target loci (Laptenko and Prives 2006). The p53 transcriptional program is regulated in a stimulus-specific fashion (Murray-Zmijewski et al. 2008; Vousden and Prives 2009), whereby distinct subsets of p53 target genes are induced in response to different p53-activating agents, likely allowing cells to tailor their response to different types of stress. How p53 is able to discriminate between these different loci is the subject of intense research. Here, we describe key aspects of the fundamentals of p53-mediated transcriptional regulation and target gene promoter selectivity.
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Affiliation(s)
- Rachel Beckerman
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Das C, Gadad SS, Kundu TK. Human Positive Coactivator 4 Controls Heterochromatinization and Silencing of Neural Gene Expression by Interacting with REST/NRSF and CoREST. J Mol Biol 2010; 397:1-12. [DOI: 10.1016/j.jmb.2009.12.058] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 12/29/2009] [Accepted: 12/30/2009] [Indexed: 10/20/2022]
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Analysis of newly established EST databases reveals similarities between heart regeneration in newt and fish. BMC Genomics 2010; 11:4. [PMID: 20047682 PMCID: PMC2823690 DOI: 10.1186/1471-2164-11-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 01/04/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The newt Notophthalmus viridescens possesses the remarkable ability to respond to cardiac damage by formation of new myocardial tissue. Surprisingly little is known about changes in gene activities that occur during the course of regeneration. To begin to decipher the molecular processes, that underlie restoration of functional cardiac tissue, we generated an EST database from regenerating newt hearts and compared the transcriptional profile of selected candidates with genes deregulated during zebrafish heart regeneration. RESULTS A cDNA library of 100,000 cDNA clones was generated from newt hearts 14 days after ventricular injury. Sequencing of 11520 cDNA clones resulted in 2894 assembled contigs. BLAST searches revealed 1695 sequences with potential homology to sequences from the NCBI database. BLAST searches to TrEMBL and Swiss-Prot databases assigned 1116 proteins to Gene Ontology terms. We also identified a relatively large set of 174 ORFs, which are likely to be unique for urodele amphibians. Expression analysis of newt-zebrafish homologues confirmed the deregulation of selected genes during heart regeneration. Sequences, BLAST results and GO annotations were visualized in a relational web based database followed by grouping of identified proteins into clusters of GO Terms. Comparison of data from regenerating zebrafish hearts identified biological processes, which were uniformly overrepresented during cardiac regeneration in newt and zebrafish. CONCLUSION We concluded that heart regeneration in newts and zebrafish led to the activation of similar sets of genes, which suggests that heart regeneration in both species might follow similar principles. The design of the newly established newt EST database allows identification of molecular pathways important for heart regeneration.
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Abstract
The p53 protein is one of the most important tumor suppressor proteins. Normally, the p53 protein is in a latent state. However, when its activity is required, e.g. upon DNA damage, nucleotide depletion or hypoxia, p53 becomes rapidly activated and initiates transcription of pro-apoptotic and cell cycle arrest-inducing target genes. The activity of p53 is regulated both by protein abundance and by post-translational modifications of pre-existing p53 molecules. In the 30 years of p53 research, a plethora of modifications and interaction partners that modulate p53's abundance and activity have been identified and new ones are continuously discovered. This review will summarize our current knowledge on the regulation of p53 abundance and activity.
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Affiliation(s)
- Karen A Boehme
- Forschungszentrum Karlsruhe, Institute of Toxicology and Genetics, Karlsruhe, Germany
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39
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Ravindra KC, Selvi BR, Arif M, Reddy BAA, Thanuja GR, Agrawal S, Pradhan SK, Nagashayana N, Dasgupta D, Kundu TK. Inhibition of lysine acetyltransferase KAT3B/p300 activity by a naturally occurring hydroxynaphthoquinone, plumbagin. J Biol Chem 2009; 284:24453-64. [PMID: 19570987 PMCID: PMC2782038 DOI: 10.1074/jbc.m109.023861] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Revised: 06/29/2009] [Indexed: 01/24/2023] Open
Abstract
Lysine acetyltransferases (KATs), p300 (KAT3B), and its close homologue CREB-binding protein (KAT3A) are probably the most widely studied KATs with well documented roles in various cellular processes. Hence, the dysfunction of p300 may result in the dysregulation of gene expression leading to the manifestation of many disorders. The acetyltransferase activity of p300/CREB-binding protein is therefore considered as a target for new generation therapeutics. We describe here a natural compound, plumbagin (RTK1), isolated from Plumbago rosea root extract, that inhibits histone acetyltransferase activity potently in vivo. Interestingly, RTK1 specifically inhibits the p300-mediated acetylation of p53 but not the acetylation by another acetyltransferase, p300/CREB-binding protein -associated factor, PCAF, in vivo. RTK1 inhibits p300 histone acetyltransferase activity in a noncompetitive manner. Docking studies and site-directed mutagenesis of the p300 histone acetyltransferase domain suggest that a single hydroxyl group of RTK1 makes a hydrogen bond with the lysine 1358 residue of this domain. In agreement with this, we found that indeed the hydroxyl group-substituted plumbagin derivatives lost the acetyltransferase inhibitory activity. This study describes for the first time the chemical entity (hydroxyl group) required for the inhibition of acetyltransferase activity.
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Affiliation(s)
- Kodihalli C. Ravindra
- From the Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064
| | - B. Ruthrotha Selvi
- From the Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064
| | - Mohammed Arif
- From the Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064
| | - B. A. Ashok Reddy
- From the Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064
| | - Gali R. Thanuja
- From the Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064
| | - Shipra Agrawal
- Institute of Bioinformatics and Applied Biotechnology, International Technology Park Bangalore, Whitefield Road, Bangalore 560066
| | - Suman Kalyan Pradhan
- Biophysics Division, Saha Institute of Nuclear Physics, I/AF, Bidhan Nagar, Kolkata 700064, India
| | - Natesh Nagashayana
- Central Government Health Scheme Dispensary Number 3, Basavanagudi, Bangalore 560004, and
| | - Dipak Dasgupta
- Biophysics Division, Saha Institute of Nuclear Physics, I/AF, Bidhan Nagar, Kolkata 700064, India
| | - Tapas K. Kundu
- From the Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064
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40
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Buganim Y, Rotter V. p53: Balancing tumour suppression and implications for the clinic. Eur J Cancer 2009; 45 Suppl 1:217-34. [DOI: 10.1016/s0959-8049(09)70037-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Rajagopalan S, Andreeva A, Teufel DP, Freund SM, Fersht AR. Interaction between the transactivation domain of p53 and PC4 exemplifies acidic activation domains as single-stranded DNA mimics. J Biol Chem 2009; 284:21728-37. [PMID: 19525231 PMCID: PMC2755895 DOI: 10.1074/jbc.m109.006429] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 06/11/2009] [Indexed: 12/03/2022] Open
Abstract
The tumor suppressor p53 regulates cell cycle arrest and apoptosis by transactivating several genes that are critical for these processes. The transcriptional activity of p53 is often regulated by post-translational modifications and its interactions with various transcriptional coactivators. Here we report a physical interaction between the N-terminal transactivation domain (TAD) of p53 and the C-terminal DNA-binding domain of positive cofactor 4 (PC4(CTD)). Using NMR spectroscopy, we showed that residues 35-57 (TAD2) interact with PC4. (15)N,(1)H HSQC and fluorescence competition experiments indicated that TAD binds to the DNA-binding site of PC4. Hepta-phosphorylation of the TAD peptide increased its binding affinity. Computer modeling of the p53N-PC4 complex revealed several important interactions that are reminiscent of those in the single-stranded DNA-PC4 complex. The ubiquitous nature of the acidic transactivation domain of p53 in mediating interactions with several transcription cofactors is also manifested as a DNA mimetic.
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Affiliation(s)
| | - Antonina Andreeva
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, United Kingdom
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Abstract
While the tumor suppressor functions of p53 have long been recognized, the contribution of p53 to numerous other aspects of disease and normal life is only now being appreciated. This burgeoning range of responses to p53 is reflected by an increasing variety of mechanisms through which p53 can function, although the ability to activate transcription remains key to p53's modus operandi. Control of p53's transcriptional activity is crucial for determining which p53 response is activated, a decision we must understand if we are to exploit efficiently the next generation of drugs that selectively activate or inhibit p53.
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Affiliation(s)
- Karen H Vousden
- The Beatson Institute for Cancer Research, Garscube Estate, Glasgow, UK.
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Shinmen N, Koshida T, Kumazawa T, Sato K, Shimada H, Matsutani T, Iwadate Y, Takiguchi M, Hiwasa T. Activation of NFAT signal by p53-K120R mutant. FEBS Lett 2009; 583:1916-22. [PMID: 19416725 DOI: 10.1016/j.febslet.2009.04.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Accepted: 04/27/2009] [Indexed: 11/20/2022]
Abstract
The tumor suppressor p53 is activated by phosphorylation and/or acetylation. We constructed 14 non-phosphorylated, 11 phospho-mimetic, and 1 non-acetylated point p53 mutations and compared their transactivation ability in U-87 human glioblastoma cells by the luciferase reporter assay. Despite mutations at the phosphorylation sites, only the p53-K120R and p53-S9E mutants had marginally reduced activities. On the other hand, the Nuclear factor of activated T-cells (NFAT)-luciferase reporter was more potently activated by p53-K120R than by wild-type p53 and other mutants in glioblastoma, hepatoma and esophageal carcinoma cells. This suggests that acetylation at Lys-120 of p53 negatively regulates a signaling pathway leading to NFAT activation.
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Affiliation(s)
- Natsuko Shinmen
- Department of Biochemistry and Genetics, Chiba University, Graduate School of Medicine, Chuo-ku, Chiba, Japan
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Placental oxidative stress alters expression of murine osteogenic genes and impairs fetal skeletal formation. Placenta 2008; 29:802-8. [PMID: 18675455 DOI: 10.1016/j.placenta.2008.06.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 06/19/2008] [Accepted: 06/22/2008] [Indexed: 11/20/2022]
Abstract
Fetal and placental developments rely on an intricate balance of nutrients, growth factors, and signaling pathways at precise times in gestation. Disruptions to this balance may result in disease that manifests in adulthood, a situation termed "developmental origins of health and disease". Diet, exercise, and certain chemical exposures during pregnancy increase oxidative stress (OS), and may alter trajectory of fetal osteogenic regulation in a manner that increases risk of adult bone dysfunction. The present study used gestational methylnitrosourea (MNU), a known inducer of OS, in C57BL/6 mice with or without dietary antioxidant quercetin (Q) supplementation. Several key placental genes that influence placental development and fetal osteogenesis (Hgf, Kitl, IFNalpha4, Ifrd, and IL-1beta) were altered by MNU, and largely normalized by Q. MNU treatment also resulted in small fetuses with disproportionately shortened limbs and distal limb malformations, and caused placental endothelial and trophoblast damage. Q was again protective against these fetal and placental pathologies. An unanticipated finding with Q supplementation was increased interdigital webbing, perhaps due to dose-related effects on apoptosis required for digital sculpting, or pro-oxidant effects of Q that caused a maturational delay. These results suggest that elevated OS may alter normal placental osteogenic signaling and fetal skeletal formation.
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Batta K, Yokokawa M, Takeyasu K, Kundu TK. Human transcriptional coactivator PC4 stimulates DNA end joining and activates DSB repair activity. J Mol Biol 2008; 385:788-99. [PMID: 19038270 DOI: 10.1016/j.jmb.2008.11.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 10/25/2008] [Accepted: 11/03/2008] [Indexed: 12/01/2022]
Abstract
Human transcriptional coactivator PC4 is a highly abundant nuclear protein that is involved in diverse cellular processes ranging from transcription to chromatin organization. Earlier, we have shown that PC4, a positive activator of p53, overexpresses upon genotoxic insult in a p53-dependent manner. In the present study, we show that PC4 stimulates ligase-mediated DNA end joining irrespective of the source of DNA ligase. Pull-down assays reveal that PC4 helps in the association of DNA ends through its C-terminal domain. In vitro nonhomologous end-joining assays with cell-free extracts show that PC4 enhances the joining of noncomplementary DNA ends. Interestingly, we found that PC4 activates double-strand break (DSB) repair activity through stimulation of DSB rejoining in vivo. Together, these findings demonstrate PC4 as an activator of nonhomologous end joining and DSB repair activity.
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Affiliation(s)
- Kiran Batta
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, PO Bangalore 560064, India
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Contreras-Levicoy J, Urbina F, Maldonado E. Schizosaccharomyces pombe positive cofactor 4 stimulates basal transcription from TATA-containing and TATA-less promoters through Mediator and transcription factor IIA. FEBS J 2008; 275:2873-83. [DOI: 10.1111/j.1742-4658.2008.06429.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Andrew AS, Jewell DA, Mason RA, Whitfield ML, Moore JH, Karagas MR. Drinking-water arsenic exposure modulates gene expression in human lymphocytes from a U.S. population. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:524-31. [PMID: 18414638 PMCID: PMC2290973 DOI: 10.1289/ehp.10861] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 01/21/2008] [Indexed: 05/18/2023]
Abstract
BACKGROUND Arsenic exposure impairs development and can lead to cancer, cardiovascular disease, and diabetes. The mechanism underlying these effects remains unknown. Primarily because of geologic sources of contamination, drinking-water arsenic levels are above the current recommended maximum contaminant level of 10 microg/L in the northeastern, western, and north central regions of the United States. OBJECTIVES We investigated the effects of arsenic exposure, defined by internal biomarkers at levels relevant to the United States and similarly exposed populations, on gene expression. METHODS We conducted separate Affymetrix microarray-based genomewide analyses of expression patterns. Peripheral blood lymphocyte samples from 21 controls interviewed (1999-2002) as part of a case-control study in New Hampshire were selected based on high- versus low-level arsenic exposure levels. RESULTS The biologic functions of the transcripts that showed statistically significant abundance differences between high- and low-arsenic exposure groups included an overrepresentation of genes involved in defense response, immune function, cell growth, apoptosis, regulation of cell cycle, T-cell receptor signaling pathway, and diabetes. Notably, the high-arsenic exposure group exhibited higher levels of several killer cell immunoglobulin-like receptors that inhibit natural killer cell activity. CONCLUSIONS These findings define biologic changes that occur with chronic arsenic exposure in humans and provide leads and potential targets for understanding and monitoring the pathogenesis of arsenic-induced diseases.
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Affiliation(s)
- Angeline S Andrew
- Dartmouth Medical School Section of Biostatistics and Epidemiology, 7927 Rubin 860, One Medical Center Dr., Lebanon, NH 03756, USA.
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