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Lin X, Ahmad A, Ivanov AI, Simhadri J, Wang S, Kumari N, Ammosova T, Nekhai S. HIV-1 Transcription Inhibitor 1E7-03 Decreases Nucleophosmin Phosphorylation. Mol Cell Proteomics 2023; 22:100488. [PMID: 36563749 PMCID: PMC9975258 DOI: 10.1016/j.mcpro.2022.100488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 12/07/2022] [Accepted: 12/18/2022] [Indexed: 12/25/2022] Open
Abstract
Transcription activation of latent human immunodeficiency virus-1 (HIV-1) occurs due to HIV-1 rebound, the interruption of combination antiretroviral therapy, or development of drug resistance. Thus, novel HIV-1 inhibitors, targeting HIV-1 transcription are needed. We previously developed an HIV-1 transcription inhibitor, 1E7-03, that binds to the noncatalytic RVxF-accommodating site of protein phosphatase 1 and inhibits HIV-1 replication in cultured cells and HIV-1-infected humanized mice by impeding protein phosphatase 1 interaction with HIV-1 Tat protein. However, host proteins and regulatory pathways targeted by 1E7-03 that contribute to its overall HIV-1 inhibitory activity remain to be identified. To address this issue, we performed label-free quantitative proteome and phosphoproteome analyses of noninfected and HIV-1-infected CEM T cells that were untreated or treated with 1E7-03. 1E7-03 significantly reprogramed the phosphorylation profile of proteins including PPARα/RXRα, TGF-β, and PKR pathways. Phosphorylation of nucleophosmin (NPM1) at Ser-125 residue in PPARα/RXRα pathway was significantly reduced (>20-fold, p = 1.37 × 10-9), followed by the reduced phosphorylation of transforming growth factor-beta 2 at Ser-46 (TGF-β2, >12-fold, p = 1.37 × 10-3). Downregulation of NPM1's Ser-125 phosphorylation was further confirmed using Western blot. Phosphorylation mimicking NPM1 S125D mutant activated Tat-induced HIV-1 transcription and exhibited enhanced NPM1-Tat interaction compared to NPM1 S125A mutant. Inhibition of Aurora A or Aurora B kinases that phosphorylate NPM1 on Ser-125 residue inhibited HIV-1, further supporting the role of NPM1 in HIV-1 infection. Taken together, 1E7-03 reprogrammed PPARα/RXRα and TGF-β pathways that contribute to the inhibition of HIV-1 transcription. Our findings suggest that NPM1 phosphorylation is a plausible target for HIV-1 transcription inhibition.
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Key Words
- actn4, alpha-actinin-1
- asl, argininosuccinate lyase
- aspm, abnormal spindle-like microcephaly-associated protein
- cart, combination antiretroviral therapy
- cdk2, cell cycle-dependent kinase 2
- ck2, casein kinase 2
- dmso, dimethyl sulfoxide
- egln1, egl-9 family hypoxia inducible factor 1
- erk/p38, extracellular signal-regulated kinase p38
- fa, formic acid
- gadd34, growth arrest and dna damage-inducible protein
- hif-1α, hypoxia-inducible factor 1α
- hiv-1 vif protein, viral infectivity factor, an hiv-1 accessory protein
- hiv-1, human immunodeficiency virus-1
- hsp90, heat shock protein 90
- ipa, ingenuity pathway analysis
- lc-ft/ms, tandem liquid chromatography-fourier transform mass spectrometry
- mapk, mitogen-activated protein kinase
- map3k4, mitogen-activated protein kinase kinase kinase 4
- mita, mediator of interferon response factor 3 activation
- nfat, nuclear factor of activated t cells
- nf-κb, nuclear factor kappa-light-chain-enhancer of activated b cell
- npm1, nucleophosmin
- oa, okadaic acid
- pi3k/akt, phosphoinositide 3-kinase/ ak strain transforming or protein kinase b
- pp, protein phosphatase
- pparα/rxrα, peroxisome proliferator-activated receptor α/ retinoid x receptor α
- ptm, posttranslational modification
- rnr2, ribonucleotide reductase 2
- rt, reverse transcription
- samhd1, sam domain and hd domain-containing protein 1
- smad7, mothers against decapentaplegic homolog 7
- stat5, signal transducer and activator of transcription 5 taf4
- taf4, transcription factor tfiid subunit tata-box-binding protein (tbp)-associated factor 4
- tgf-β2, transforming growth factor-beta
- tp53, tumor protein p53
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Affiliation(s)
- Xionghao Lin
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA; College of Dentistry, Howard University, Washington, District of Columbia, USA
| | - Asrar Ahmad
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Andrey I Ivanov
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Jyothirmai Simhadri
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Songping Wang
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Namita Kumari
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA; Department of Microbiology, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Tatiana Ammosova
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA; Department of Medicine, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Sergei Nekhai
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA; Department of Microbiology, College of Medicine, Howard University, Washington, District of Columbia, USA; Department of Medicine, College of Medicine, Howard University, Washington, District of Columbia, USA.
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Yang T, He R, Li G, Liang J, Zhao L, Zhao X, Li L, Wang P. Growth arrest and DNA damage-inducible protein 34 (GADD34) contributes to cerebral ischemic injury and can be detected in plasma exosomes. Neurosci Lett 2021; 758:136004. [PMID: 34098025 DOI: 10.1016/j.neulet.2021.136004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 10/21/2022]
Abstract
Growth arrest and DNA damage-inducible protein 34 (GADD34), one of the key effectors of negative feedback loops, is induced by stress and subsequently attempts to restore homeostasis. It plays a critical role in response to DNA damage and endoplasmic reticulum stress. GADD34 has opposing effects on different stimulus-induced cell apoptosis events in many nervous system diseases, but its role in ischemic stroke is unclear. In this study, we evaluated the role of GADD34 and its distribution in a rat cerebral ischemic model. The results showed that GADD34 was increased in the cortex and contributed to brain injury in ischemic rats. Furthermore, treatment with a GADD34 inhibitor reduced the infarct volume, improved functional outcomes, and inhibited neuronal apoptosis in the cortical penumbra after ischemia. The role of GADD34 in ischemic stroke was associated with the dephosphorylation of eukaryotic translation initiation factor 2α (eIF2α) and phosphorylation of p53. In addition, the GADD34 level was increased in plasma exosomes of cerebral ischemic rats. These findings indicate that GADD34 could be a potential therapeutic target and biomarker for ischemic stroke.
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Affiliation(s)
- Tianhui Yang
- Department of Neurobiology and Key Laboratory of Neurodegenerative Diseases of Liaoning Province, Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Ruyi He
- College of Pharmacy, Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Gongzhe Li
- College of Pharmacy, Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Jia Liang
- Institution of Life Science, Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Liang Zhao
- College of Pharmacy, Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Xing Zhao
- Department of Ophthalmology and Otolaryngology, Liaoning Provincial Corps Hospital of Chinese People's Armed Police Forces, Shenyang, Liaoning, China
| | - Liyang Li
- Department of Ophthalmology and Otolaryngology, Liaoning Provincial Corps Hospital of Chinese People's Armed Police Forces, Shenyang, Liaoning, China
| | - Peng Wang
- Department of Neurobiology and Key Laboratory of Neurodegenerative Diseases of Liaoning Province, Jinzhou Medical University, Jinzhou, Liaoning, China.
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Cell Cycle and DNA Repair Regulation in the Damage Response: Protein Phosphatases Take Over the Reins. Int J Mol Sci 2020; 21:ijms21020446. [PMID: 31936707 PMCID: PMC7014277 DOI: 10.3390/ijms21020446] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/29/2019] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Cells are constantly suffering genotoxic stresses that affect the integrity of our genetic material. Genotoxic insults must be repaired to avoid the loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental abnormalities and tumorigenesis. To combat this threat, eukaryotic cells have evolved a set of sophisticated molecular mechanisms that are collectively known as the DNA damage response (DDR). This surveillance system controls several aspects of the cellular response, including the detection of lesions, a temporary cell cycle arrest, and the repair of the broken DNA. While the regulation of the DDR by numerous kinases has been well documented over the last decade, the complex roles of protein dephosphorylation have only recently begun to be investigated. Here, we review recent progress in the characterization of DDR-related protein phosphatases during the response to a DNA lesion, focusing mainly on their ability to modulate the DNA damage checkpoint and the repair of the damaged DNA. We also discuss their protein composition and structure, target specificity, and biochemical regulation along the different stages encompassed in the DDR. The compilation of this information will allow us to better comprehend the physiological significance of protein dephosphorylation in the maintenance of genome integrity and cell viability in response to genotoxic stress.
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Ramos F, Villoria MT, Alonso-Rodríguez E, Clemente-Blanco A. Role of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DNA damage response. Cell Stress 2019; 3:70-85. [PMID: 31225502 PMCID: PMC6551743 DOI: 10.15698/cst2019.03.178] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Maintenance of genome integrity is fundamental for cellular physiology. Our hereditary information encoded in the DNA is intrinsically susceptible to suffer variations, mostly due to the constant presence of endogenous and environmental genotoxic stresses. Genomic insults must be repaired to avoid loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental anomalies and tumorigenesis. To safeguard our genome, cells have evolved a series of mechanisms collectively known as the DNA damage response (DDR). This surveillance system regulates multiple features of the cellular response, including the detection of the lesion, a transient cell cycle arrest and the restoration of the broken DNA molecule. While the role of multiple kinases in the DDR has been well documented over the last years, the intricate roles of protein dephosphorylation have only recently begun to be addressed. In this review, we have compiled recent information about the function of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DDR, focusing mainly on their capacity to regulate the DNA damage checkpoint and the repair mechanism encompassed in the restoration of a DNA lesion.
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Affiliation(s)
- Facundo Ramos
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - María Teresa Villoria
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Esmeralda Alonso-Rodríguez
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
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5
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Gil RS, Vagnarelli P. Protein phosphatases in chromatin structure and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:90-101. [PMID: 30036566 PMCID: PMC6227384 DOI: 10.1016/j.bbamcr.2018.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/29/2018] [Accepted: 07/18/2018] [Indexed: 12/19/2022]
Abstract
Chromatin structure and dynamics are highly controlled and regulated processes that play an essential role in many aspects of cell biology. The chromatin transition stages and the factors that control this process are regulated by post-translation modifications, including phosphorylation. While the role of protein kinases in chromatin dynamics has been quite well studied, the nature and regulation of the counteracting phosphatases represent an emerging field but are still at their infancy. In this review we summarize the current literature on phosphatases involved in the regulation of chromatin structure and dynamics, with emphases on the major knowledge gaps that should require attention and more investigation.
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Affiliation(s)
- Raquel Sales Gil
- Colleges of Health and Life Science, Research Institute for Environment Health and Society, Brunel University London, London UB8 3PH, UK
| | - Paola Vagnarelli
- Colleges of Health and Life Science, Research Institute for Environment Health and Society, Brunel University London, London UB8 3PH, UK.
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McKinley KL, Cheeseman IM. Large-Scale Analysis of CRISPR/Cas9 Cell-Cycle Knockouts Reveals the Diversity of p53-Dependent Responses to Cell-Cycle Defects. Dev Cell 2017; 40:405-420.e2. [PMID: 28216383 DOI: 10.1016/j.devcel.2017.01.012] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/23/2016] [Accepted: 01/23/2017] [Indexed: 12/20/2022]
Abstract
Defining the genes that are essential for cellular proliferation is critical for understanding organismal development and identifying high-value targets for disease therapies. However, the requirements for cell-cycle progression in human cells remain incompletely understood. To elucidate the consequences of acute and chronic elimination of cell-cycle proteins, we generated and characterized inducible CRISPR/Cas9 knockout human cell lines targeting 209 genes involved in diverse cell-cycle processes. We performed single-cell microscopic analyses to systematically establish the effects of the knockouts on subcellular architecture. To define variations in cell-cycle requirements between cultured cell lines, we generated knockouts across cell lines of diverse origins. We demonstrate that p53 modulates the phenotype of specific cell-cycle defects through distinct mechanisms, depending on the defect. This work provides a resource to broadly facilitate robust and long-term depletion of cell-cycle proteins and reveals insights into the requirements for cell-cycle progression.
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Affiliation(s)
- Kara L McKinley
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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7
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Bergmann J, Müller M, Baumann N, Reichert M, Heneweer C, Bolik J, Lücke K, Gruber S, Carambia A, Boretius S, Leuschner I, Becker T, Rabe B, Herkel J, Wunderlich FT, Mittrücker HW, Rose-John S, Schmidt-Arras D. IL-6 trans-signaling is essential for the development of hepatocellular carcinoma in mice. Hepatology 2017; 65:89-103. [PMID: 27770462 DOI: 10.1002/hep.28874] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 09/08/2016] [Accepted: 09/11/2016] [Indexed: 12/11/2022]
Abstract
UNLABELLED Hepatocellular carcinoma (HCC) is one of the most frequent tumors worldwide with rising incidence. The inflammatory cytokine, interleukin-6 (IL-6), is a critical mediator of HCC development. It can signal through two distinct pathways: the IL-6 classic and the IL-6 trans-signaling pathway. Whereas IL-6 classic signaling is important for innate and acquired immunity, IL-6 trans-signaling has been linked to accelerated liver regeneration and several chronic inflammatory pathologies. However, its implication in liver tumorigenesis has not been addressed yet. Here, we show that IL-6 trans-signaling, but not IL-6 classic signaling, is essential to promote hepatocellular carcinogenesis by two mechanisms: First, it prevents DNA-damage-induced hepatocyte apoptosis through suppression of p53 and enhances β-catenin activation and tumor proliferation. Second, IL-6 trans-signaling directly induces endothelial cell proliferation to promote tumor angiogenesis. Consequently, soluble gp130 fused to Fc transgenic mice lacking IL-6 trans-signaling are largely protected from tumor formation in a diethylnitrosamine/3,3',5,5'-tetrachloro-1,4-bis(pyridyloxy)benzene model of HCC. CONCLUSION IL-6 trans-signaling, and not IL-6 classic signaling, is mandatory for development of hepatocellular carcinogenesis. Therefore, specific inhibition of IL-6 trans-signaling, rather than total inhibition of IL-6 signaling, is sufficient to blunt tumor initiation and impair tumor progression without compromising IL-6 classic signaling-driven protective immune responses. (Hepatology 2017;65:89-103).
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Affiliation(s)
- Juri Bergmann
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany.,Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Miryam Müller
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Niklas Baumann
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Manuel Reichert
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany.,Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Carola Heneweer
- Department of Radiology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Julia Bolik
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Karsten Lücke
- Institute of Immunology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Sabine Gruber
- Max-Planck-Institute for Metabolism Research, CECAD and Institute for Genetics, Cologne, Germany
| | - Antonella Carambia
- Department of Medicine I, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Boretius
- Department of Radiology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Ivo Leuschner
- Institute of Pathology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Thomas Becker
- Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Björn Rabe
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Johannes Herkel
- Department of Medicine I, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - F Thomas Wunderlich
- Max-Planck-Institute for Metabolism Research, CECAD and Institute for Genetics, Cologne, Germany
| | - Hans-Willi Mittrücker
- Institute of Immunology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Stefan Rose-John
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Dirk Schmidt-Arras
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany
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8
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Otsuka R, Harada N, Aoki S, Shirai K, Nishitsuji K, Nozaki A, Hatakeyama A, Shono M, Mizusawa N, Yoshimoto K, Nakaya Y, Kitahata H, Sakaue H. C-terminal region of GADD34 regulates eIF2α dephosphorylation and cell proliferation in CHO-K1 cells. Cell Stress Chaperones 2016; 21:29-40. [PMID: 26318739 PMCID: PMC4679745 DOI: 10.1007/s12192-015-0633-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/05/2015] [Accepted: 08/10/2015] [Indexed: 10/23/2022] Open
Abstract
GADD34 is a member of a growth arrest and DNA damage (GADD)-inducible gene family. Here, we established a novel Chinese hamster ovary (CHO)-K1-derived cell line, CHO-K1-G34M, which carries a nonsense mutation (termed the Q525X mutation) in the GADD34 gene. The Q525X mutant protein lacks the C-terminal 66 amino acids required for GADD34 to bind to and activate protein phosphatase 1 (PP1). We investigated the effects of GADD34 with or without the Q525X mutation on the phosphorylation status of PP1 target proteins, including the α subunit of eukaryotic initiation factor 2 (eIF2α) and glycogen synthase kinase 3β (GSK3β). CHO-K1-G34M cells had higher levels of eIF2α phosphorylation compared to the control CHO-K1-normal cells both in the presence and absence of endoplasmic reticulum stress. Overexpression of the wild-type GADD34 protein in CHO-K1-normal cells largely reduced eIF2α phosphorylation, while overexpression of the Q525X mutant did not produce similar reductions. Meanwhile, neither wild type nor Q525X mutation of GADD34 affected the GSK3β phosphorylation status. GADD34 also did not affect the canonical Wnt signaling pathway downstream of GSK3β. Cell proliferation rates were higher, while expression levels of the cyclin-dependent kinase inhibitor p21 were lower in CHO-K1-G34M cells compared to the CHO-K1-normal cells. The GADD34 Q525X mutant had a reduced ability to inhibit cell proliferation and enhance p21 expression of the CHO-K1-normal cells compared to the wild-type GADD34 protein. These results suggest that the GADD34 protein C-terminal plays important roles in regulating not only eIF2α dephosphorylation but also cell proliferation in CHO-K1 cells.
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Affiliation(s)
- Ryo Otsuka
- Department of Dental Anesthesiology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8504, Japan
| | - Nagakatsu Harada
- Department of Nutrition and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan.
| | - Shouhei Aoki
- Department of Nutrition and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan
| | - Kanna Shirai
- Department of Nutrition and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan
| | - Kazuchika Nishitsuji
- Department of Molecular Pathology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan
| | - Ayane Nozaki
- Department of Nutrition and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan
| | - Adzumi Hatakeyama
- Department of Nutrition and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan
| | - Masayuki Shono
- Support Center for Advanced Medical Sciences, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan
| | - Noriko Mizusawa
- Department of Medical Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8504, Japan
| | - Katsuhiko Yoshimoto
- Department of Medical Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8504, Japan
| | - Yutaka Nakaya
- Department of Nutrition and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan
| | - Hiroshi Kitahata
- Department of Dental Anesthesiology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8504, Japan
| | - Hiroshi Sakaue
- Department of Nutrition and Metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Tokushima City, 770-8503, Japan
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Stamper BD, Garcia ML, Nguyen DQ, Beyer RP, Bammler TK, Farin FM, Kavanagh TJ, Nelson SD. p53 Contributes to Differentiating Gene Expression Following Exposure to Acetaminophen and Its Less Hepatotoxic Regioisomer Both In Vitro and In Vivo. GENE REGULATION AND SYSTEMS BIOLOGY 2015; 9:1-14. [PMID: 26056430 PMCID: PMC4454132 DOI: 10.4137/grsb.s25388] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/06/2015] [Accepted: 04/14/2015] [Indexed: 01/20/2023]
Abstract
The goal of the present study was to compare hepatic toxicogenomic signatures across in vitro and in vivo mouse models following exposure to acetaminophen (APAP) or its relatively nontoxic regioisomer 3′-hydroxyacetanilide (AMAP). Two different Affymetrix microarray platforms and one Agilent Oligonucleotide microarray were utilized. APAP and AMAP treatments resulted in significant and large changes in gene expression that were quite disparate, and likely related to their different toxicologic profiles. Ten transcripts, all of which have been implicated in p53 signaling, were identified as differentially regulated at all time-points following APAP and AMAP treatments across multiple microarray platforms. Protein-level quantification of p53 activity aligned with results from the transcriptomic analysis, thus supporting the implicated mechanism of APAP-induced toxicity. Therefore, the results of this study provide good evidence that APAP-induced p53 phosphorylation and an altered p53-driven transcriptional response are fundamental steps in APAP-induced toxicity.
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Affiliation(s)
| | | | - Duy Q Nguyen
- School of Pharmacy, Pacific University, Hillsboro, OR, USA
| | - Richard P Beyer
- Department of Environmental and Occupational Health Sciences, University Of Washington, Seattle, WA, USA
| | - Theo K Bammler
- Department of Environmental and Occupational Health Sciences, University Of Washington, Seattle, WA, USA
| | - Frederico M Farin
- Department of Environmental and Occupational Health Sciences, University Of Washington, Seattle, WA, USA
| | - Terrance J Kavanagh
- Department of Environmental and Occupational Health Sciences, University Of Washington, Seattle, WA, USA
| | - Sidney D Nelson
- Department of Medicinal Chemistry, University Of Washington, Seattle, WA, USA
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10
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Ban J, Aryee DNT, Fourtouna A, van der Ent W, Kauer M, Niedan S, Machado I, Rodriguez-Galindo C, Tirado OM, Schwentner R, Picci P, Flanagan AM, Berg V, Strauss SJ, Scotlandi K, Lawlor ER, Snaar-Jagalska E, Llombart-Bosch A, Kovar H. Suppression of deacetylase SIRT1 mediates tumor-suppressive NOTCH response and offers a novel treatment option in metastatic Ewing sarcoma. Cancer Res 2014; 74:6578-88. [PMID: 25281719 DOI: 10.1158/0008-5472.can-14-1736] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The developmental receptor NOTCH plays an important role in various human cancers as a consequence of oncogenic mutations. Here we describe a novel mechanism of NOTCH-induced tumor suppression involving modulation of the deacetylase SIRT1, providing a rationale for the use of SIRT1 inhibitors to treat cancers where this mechanism is inactivated because of SIRT1 overexpression. In Ewing sarcoma cells, NOTCH signaling is abrogated by the driver oncogene EWS-FLI1. Restoration of NOTCH signaling caused growth arrest due to activation of the NOTCH effector HEY1, directly suppressing SIRT1 and thereby activating p53. This mechanism of tumor suppression was validated in Ewing sarcoma cells, B-cell tumors, and human keratinocytes where NOTCH dysregulation has been implicated pathogenically. Notably, the SIRT1/2 inhibitor Tenovin-6 killed Ewing sarcoma cells in vitro and prohibited tumor growth and spread in an established xenograft model in zebrafish. Using immunohistochemistry to analyze primary tissue specimens, we found that high SIRT1 expression was associated with Ewing sarcoma metastasis and poor prognosis. Our findings suggest a mechanistic rationale for the use of SIRT1 inhibitors being developed to treat metastatic disease in patients with Ewing sarcoma.
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Affiliation(s)
- Jozef Ban
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Dave N T Aryee
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria. Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Argyro Fourtouna
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Wietske van der Ent
- Institute of Biology and Department of Pathology, Leiden University, Leiden, The Netherlands
| | - Max Kauer
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Stephan Niedan
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Isidro Machado
- Department of Pathology, University Medical School, València, Spain
| | | | - Oscar M Tirado
- Laboratori d'Oncología Molecular, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Raphaela Schwentner
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Piero Picci
- Laboratory of Experimental Oncology, Rizzoli Institute, Bologna, Italy
| | | | - Verena Berg
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Sandra J Strauss
- UCL Cancer Institute, University College London, London, United Kingdom
| | - Katia Scotlandi
- Laboratory of Experimental Oncology, Rizzoli Institute, Bologna, Italy
| | - Elizabeth R Lawlor
- Translational Oncology Program, Departments of Pediatrics and Pathology, University of Michigan, Ann Arbor, Michigan
| | - Ewa Snaar-Jagalska
- Institute of Biology and Department of Pathology, Leiden University, Leiden, The Netherlands
| | | | - Heinrich Kovar
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria. Department of Pediatrics, Medical University of Vienna, Vienna, Austria.
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11
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Estevez-Garcia P, Lopez-Calderero I, Molina-Pinelo S, Muñoz-Galvan S, Salinas A, Gomez-Izquierdo L, Lucena-Cacace A, Felipe-Abrio B, Paz-Ares L, Garcia-Carbonero R, Carnero A. Spinophilin loss correlates with poor patient prognosis in advanced stages of colon carcinoma. Clin Cancer Res 2013; 19:3925-35. [PMID: 23729363 DOI: 10.1158/1078-0432.ccr-13-0057] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The genomic region 17q21 is frequently associated with microsatellite instability and LOH in cancer, including gastric and colorectal carcinomas. This region contains several putative tumor suppressor genes, including Brca1, NM23, prohibitin, and spinophilin (Spn, PPP1R9B, neurabin II). The scaffold protein Spn is one of the regulatory subunits of phosphatase-1 (PP1) that targets PP1 to distinct subcellular locations and couples PP1 to its target. Thus, Spn may alter cell-cycle progression via the regulation of the phosphorylation status of the retinoblastoma protein, a direct target of PP1. Therefore, we analyzed whether Spn levels were reduced in colorectal carcinomas and whether Spn levels correlated with prognosis or response to therapy. EXPERIMENTAL DESIGN By means of immunohistochemistry or quantitative PCR, we studied the levels of Spn in stages II, III, and IV colorectal carcinoma tumors and correlated to other clinicopathologic features as well as prognosis or response to therapy. RESULTS Spn was lost in a percentage of human gastric, small intestine, and colorectal carcinomas. In patients with colorectal carcinoma, tumoral Spn downregulation correlated with a more aggressive histologic phenotype (poorer tumor differentiation and higher proliferative Ki67 index). Consistent with this observation, lower Spn protein expression levels were associated with faster relapse and poorer survival in patients with stage III colorectal carcinoma, particularly among those receiving adjuvant fluoropyrimidine therapy. We validated this result in an independent cohort of patients with metastatic colorectal carcinoma treated with standard chemotherapy. Although patients that achieved an objective tumor response exhibited Spn levels similar to nontumoral tissue, nonresponding patients showed a significant reduction in Spn mRNA levels. CONCLUSIONS Our data suggest that Spn downregulation contributes to a more aggressive biologic behavior, induces chemoresistance, and is associated with a poorer survival in patients with advanced stages of colorectal carcinoma.
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12
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Protein phosphatase 1 inhibits p53 signaling by dephosphorylating and stabilizing Mdmx. Cell Signal 2012; 25:796-804. [PMID: 23277204 DOI: 10.1016/j.cellsig.2012.12.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/16/2012] [Accepted: 12/21/2012] [Indexed: 12/17/2022]
Abstract
The activation and stabilization of the p53 protein play a major role in the DNA damage response. Protein levels of p53 are tightly controlled by transcriptional regulation and a number of positive and negative posttranslational modifiers, including kinases, phosphatases, E3 ubiquitin ligases, deubiquitinases, acetylases and deacetylases. One of the primary p53 regulators is Mdmx. Despite its RING domain and structural similarity with Mdm2, Mdmx does not have an intrinsic ligase activity, but inhibits the transcriptional activity of p53. Previous studies reported that Mdmx is phosphorylated and destabilized in response to DNA damage stress. Three phosphorylation sites identified are Ser342, Ser367, and Ser403. In the present study, we identify protein phosphatase 1 (PP1) as a negative regulator in the p53 signaling pathway. PP1 directly interacts with Mdmx and specifically dephosphorylates Mdmx at Ser367. The dephosphorylation of Mdmx increases its stability and thereby inhibits p53 activity. Our results suggest that PP1 is a crucial component in the ATM-Chk2-p53 signaling pathway.
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13
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14
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Kim DH, Kundu JK, Surh YJ. Redox modulation of p53: mechanisms and functional significance. Mol Carcinog 2011; 50:222-34. [PMID: 21465572 DOI: 10.1002/mc.20709] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The tumor suppressor protein p53 functions as a stress-responsive transcription factor. In response to oxidative, nitrosative, and electrophilic insults, p53 undergoes post-translational modifications, such as oxidation and covalent modification of cysteines, nitration of tyrosines, acetylation of lysines, phosphorylation of serine/threonine residues, etc. Because p53 plays a vital role in the transcriptional regulation of genes encoding proteins involved in a wide spectrum of biochemical processes including DNA repair, cell-cycle regulation, and programmed cell death, the redox-modification of p53 appears to be an important determinant of cell fate. This review highlights the redox regulation of p53 and its consequences on cellular function.
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Affiliation(s)
- Do-Hee Kim
- College of Pharmacy, Seoul National University, Seoul, South Korea
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15
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Ozaki T, Nakagawara A. Role of p53 in Cell Death and Human Cancers. Cancers (Basel) 2011; 3:994-1013. [PMID: 24212651 PMCID: PMC3756401 DOI: 10.3390/cancers3010994] [Citation(s) in RCA: 398] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 02/22/2011] [Accepted: 02/22/2011] [Indexed: 02/08/2023] Open
Abstract
p53 is a nuclear transcription factor with a pro-apoptotic function. Since over 50% of human cancers carry loss of function mutations in p53 gene, p53 has been considered to be one of the classical type tumor suppressors. Mutant p53 acts as the dominant-negative inhibitor toward wild-type p53. Indeed, mutant p53 has an oncogenic potential. In some cases, malignant cancer cells bearing p53 mutations display a chemo-resistant phenotype. In response to a variety of cellular stresses such as DNA damage, p53 is induced to accumulate in cell nucleus to exert its pro-apoptotic function. Activated p53 promotes cell cycle arrest to allow DNA repair and/or apoptosis to prevent the propagation of cells with serious DNA damage through the transactivation of its target genes implicated in the induction of cell cycle arrest and/or apoptosis. Thus, the DNA-binding activity of p53 is tightly linked to its tumor suppressive function. In the present review article, we describe the regulatory mechanisms of p53 and also p53-mediated therapeutic strategies to cure malignant cancers.
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Affiliation(s)
- Toshinori Ozaki
- Laboratory of Anti-tumor Research, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuoh-ku, Chiba 260-8717, Japan; E-Mail:
| | - Akira Nakagawara
- Division of Biochemistry and Laboratory of Innovative Cancer Therapeutics, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuoh-ku, Chiba 260-8717, Japan
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +81-43-264-5431; Fax: +81-43-265-4459
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16
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Abstract
DNA fragmentation is a hallmark of apoptosis that is induced by apoptotic stimuli in various cell types. Apoptotic signal pathways, which eventually cause DNA fragmentation, are largely mediated by the family of cysteinyl aspartate-specific protease caspases. Caspases mediate apoptotic signal transduction by cleavage of apoptosis-implicated proteins and the caspases themselves. In the process of caspase activation, reversible protein phosphorylation plays an important role. The activation of various proteins is regulated by phosphorylation and dephosphorylation, both upstream and downstream of caspase activation. Many kinases/phosphatases are involved in the control of cell survival and death, including the mitogen-activated protein kinase signal transduction pathways. Reversible protein phosphorylation is involved in the widespread regulation of cellular signal transduction and apoptotic processes. Therefore, phosphatase/kinase inhibitors are commonly used as apoptosis inducers/inhibitors. Whether protein phosphorylation induces apoptosis depends on many factors, such as the type of phosphorylated protein, the degree of activation and the influence of other proteins. Phosphorylation signaling pathways are intricately interrelated; it was previously shown that either induction or inhibition of phosphorylation causes cell death. Determination of the relationship between protein and phosphorylation helps to reveal how apoptosis is regulated. Here we discuss DNA fragmentation and protein phosphorylation, focusing on caspase and serine/threonine protein phosphatase activation.
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Affiliation(s)
- Ikuko Kitazumi
- Bio Process Research and Development Laboratories, Kyowa Hakko Kirin Co. Ltd, Takasaki, Gunma, Japan
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17
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Ozaki T, Nakagawara A. p53: the attractive tumor suppressor in the cancer research field. J Biomed Biotechnol 2010; 2011:603925. [PMID: 21188172 PMCID: PMC3004423 DOI: 10.1155/2011/603925] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 10/07/2010] [Indexed: 01/16/2023] Open
Abstract
p53 is one of the most studied tumor suppressors in the cancer research field. Of note, over 50% of human tumors carry loss of function mutations, and thus p53 has been considered to be a classical Knudson-type tumor suppressor. From the functional point of view, p53 is a nuclear transcription factor to transactivate a variety of its target genes implicated in the induction of cell cycle arrest, DNA repair, and apoptotic cell death. In response to cellular stresses such as DNA damage, p53 is activated and promotes cell cycle arrest followed by the replacement of DNA lesions and/or apoptotic cell death. Therefore, p53 is able to maintain the genomic integrity to prevent the accumulation of genetic alterations, and thus stands at a crossroad between cell survival and cell death. In this paper, we describe a variety of molecular mechanisms behind the regulation of p53.
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Affiliation(s)
- Toshinori Ozaki
- Laboratory of Anti-Tumor Research, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan
| | - Akira Nakagawara
- Laboratory of Innovative Cancer Therapeutics, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuoh-ku, Chiba 260-8717, Japan
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18
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Abstract
The cellular response to DNA damage is a crucial surveillance mechanism that maintains genomic integrity and prevents cancer progression. Previous studies identified multiple Ser/Thr protein kinases that have pivotal roles in the activation of this response. It is interesting that a growing body of evidence suggests that these kinases and their substrates are under tight modulation by numerous Ser/Thr phosphatases. In this study, we review recent reports that reveal new functions and regulation of these phosphatases. Similar to the kinases in this pathway, phosphatases may also be intimately involved in cancer progression and present valuable targets for cancer therapy.
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19
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Carlessi L, Buscemi G, Fontanella E, Delia D. A protein phosphatase feedback mechanism regulates the basal phosphorylation of Chk2 kinase in the absence of DNA damage. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:1213-23. [PMID: 20599567 DOI: 10.1016/j.bbamcr.2010.06.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 05/20/2010] [Accepted: 06/14/2010] [Indexed: 12/11/2022]
Abstract
The checkpoint kinase Chk2 is an effector component of the ATM-dependent DNA damage response (DDR) pathway. The activation of Chk2 by genotoxic stress involves its phosphorylation on T68 by ATM and additional auto/transphosphorylations. Here we demonstrate that in unperturbed cells, chemical inhibition of Chk2 by VRX0466617 (VRX) enhances the phosphorylation of Chk2-T68 throughout the cell cycle phases. This event, dependent on the presence of ATM and catalytically functional Chk2, is not consequential to DNA damage, as neither gamma-H2AX nuclear foci nor increased ATM activation is detected in VRX-treated cells, suggesting the involvement of other regulatory proteins. As serine/threonine protein phosphatases (PPs) regulate the phosphorylation and deactivation of proteins of the DDR pathway, we analyzed their role in phospho-T68-Chk2 regulation. We found that intracellular inhibition of PP1 and PP2A-like activities by okadaic acid markedly raised the accumulation of Chk2-pT68 without DNA damage induction, and this phenomenon was also seen when PP1-C, PP2A-C, and Wip1/PPM1D were simultaneously knockdown by siRNA. Altogether, these data indicate a novel mechanism in undamaged cells where PPs function to maintain the balance between ATM and its direct substrate Chk2 through a regulatory circuit.
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Affiliation(s)
- Luigi Carlessi
- Dept of Experimental Oncology, Fondazione IRCCS Istituto Nazionale Tumori, Milano, Italy
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20
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Inhibitory role of cAMP on doxorubicin-induced apoptosis in pre-B ALL cells through dephosphorylation of p53 serine residues. Apoptosis 2010; 15:196-203. [PMID: 19882354 DOI: 10.1007/s10495-009-0417-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Exposure of cells to chemotherapeutic drug doxorubicin, a DNA-damaging agent, induces an increase in the levels and activity of the wild-type p53 protein. Less well appreciated was the effect of cAMP levels on posttranslational modifications of p53 in response to doxorubicin. Here we show that elevation of cAMP in pre-B acute lymphoblastic leukemia NALM-6 cells significantly attenuated phosphorylation state of p53 at Ser6, Ser9, Ser15, Ser20, Ser37, Ser46 and Ser392 upon exposure to doxorubicin. Increased cAMP levels also shifted the ratio of the death promoter to death repressor genes via alteration of Bcl-2 and Bax proteins expression. In conclusion, our results suggest that activation of cAMP-signaling system may repress p53-dependent apoptosis in malignant cells exposed to doxorubicin.
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21
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Mi J, Bolesta E, Brautigan DL, Larner JM. PP2A regulates ionizing radiation-induced apoptosis through Ser46 phosphorylation of p53. Mol Cancer Ther 2009; 8:135-40. [PMID: 19139122 DOI: 10.1158/1535-7163.mct-08-0457] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In response to ionizing radiation, p53 plays a critical role in regulating DNA repair and apoptosis. Among multiple phosphorylation sites, evidence suggests that Ser46 promotes apoptotic cell death through mitochondrial outer membrane permeabilization (MOMP) and subsequent activation of the caspase 7-PARP pathway. Therefore, we investigated which phosphatase regulates Ser46 after ionizing radiation, reasoning that the responsible phosphatase should be a target for radiosensitization. We determined that both inhibition of PP2A by the cell-permeable inhibitor calyculin A and knockdown of PP2A by RNAi (a) enhanced Ser46 phosphorylation in p53 and (b) induced coincident caspase 7 and PARP cleavage in response to ionizing radiation. Furthermore, mutation of p53 Ser46 to Ala attenuated ionizing radiation-induced apoptotic signaling. Consequently, we concluded that PP2A regulates ionizing radiation-induced apoptotic signaling through dephosphorylation of p53 Ser46.
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Affiliation(s)
- Jun Mi
- Department of Radiation Oncology, Center for Cell Signaling, University of Virginia Health System, Box 800383 Charlottesville, VA, USA
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22
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Imbeault M, Ouellet M, Tremblay MJ. Microarray study reveals that HIV-1 induces rapid type-I interferon-dependent p53 mRNA up-regulation in human primary CD4+ T cells. Retrovirology 2009; 6:5. [PMID: 19146679 PMCID: PMC2637825 DOI: 10.1186/1742-4690-6-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 01/15/2009] [Indexed: 11/10/2022] Open
Abstract
Background Infection with HIV-1 has been shown to alter expression of a large array of host cell genes. However, previous studies aimed at investigating the putative HIV-1-induced modulation of host gene expression have been mostly performed in established human cell lines. To better approximate natural conditions, we monitored gene expression changes in a cell population highly enriched in human primary CD4+ T lymphocytes exposed to HIV-1 using commercial oligonucleotide microarrays from Affymetrix. Results We report here that HIV-1 influences expression of genes related to many important biological processes such as DNA repair, cellular cycle, RNA metabolism and apoptosis. Notably, expression of the p53 tumor suppressor and genes involved in p53 homeostasis such as GADD34 were up-regulated by HIV-1 at the mRNA level. This observation is distinct from the previously reported p53 phosphorylation and stabilization at the protein level, which precedes HIV-1-induced apoptosis. We present evidence that the HIV-1-mediated increase in p53 gene expression is associated with virus-mediated induction of type-I interferon (i.e. IFN-α and IFN-β). Conclusion These observations have important implications for our understanding of HIV-1 pathogenesis, particularly in respect to the virus-induced depletion of CD4+ T cells.
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Affiliation(s)
- Michaël Imbeault
- Centre de Recherche en Infectiologie, Centre Hospitalier de l'Université Laval, and Faculté de Médecine, Université Laval, Québec, Canada.
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23
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Tchivilev I, Madamanchi NR, Vendrov AE, Niu XL, Runge MS. Identification of a protective role for protein phosphatase 1cgamma1 against oxidative stress-induced vascular smooth muscle cell apoptosis. J Biol Chem 2008; 283:22193-205. [PMID: 18540044 DOI: 10.1074/jbc.m803452200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The development of therapeutic strategies to inhibit reactive oxygen species (ROS)-mediated damage in blood vessels has been limited by a lack of specific targets for intervention. Targeting ROS-mediated events in the vessel wall is of interest, because ROS play important roles throughout atherogenesis. In early atherosclerosis, ROS stimulate vascular smooth muscle cell (VSMC) growth, whereas in late stages of lesion development, ROS induce VSMC apoptosis, causing atherosclerotic plaque instability. To identify putative protective genes against oxidative stress, mouse aortic VSMC were infected with a retroviral human heart cDNA expression library, and apoptosis was induced in virus-infected cells by 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) treatment. A total of 17 different, complete cDNAs were identified from the DMNQ-resistant VSMC clones by PCR amplification and sequencing. The cDNA encoding PP1cgamma1 (catalytic subunit of protein phosphatase 1) was present in several independent DMNQ-resistant VSMC clones. DMNQ increased mitochondrial ROS production, caspase-3/7 activity, DNA fragmentation, and decreased mitochondrial transmembrane potential in VSMC while decreasing PP1cgamma1 activity and expression. Depletion of PP1cgamma1 expression by short hairpin RNA significantly enhanced basal as well as DMNQ-induced VSMC apoptosis. PP1cgamma1 overexpression abrogated DMNQ-induced JNK1 activity, p53 Ser(15) phosphorylation, and Bax expression and protected VSMC against DMNQ-induced apoptosis. In addition, PP1cgamma1 overexpression attenuated DMNQ-induced caspase-3/7 activation and DNA fragmentation. Inhibition of p53 protein expression using small interfering RNA abrogated DMNQ-induced Bax expression and significantly attenuated VSMC apoptosis. Together, these data indicate that PP1cgamma1 overexpression promotes VSMC survival by interfering with JNK1 and p53 phosphorylation cascades involved in apoptosis.
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Affiliation(s)
- Igor Tchivilev
- Department of Medicine, Carolina Cardiovascular Biology Center, University of North Carolina, Chapel Hill, North Carolina 27599-7126, USA
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24
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Patterns of microcystin-LR induced alteration of the expression of genes involved in response to DNA damage and apoptosis. Toxicon 2008; 51:615-23. [DOI: 10.1016/j.toxicon.2007.11.009] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 11/16/2007] [Accepted: 11/19/2007] [Indexed: 11/19/2022]
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25
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Lee SJ, Lim CJ, Min JK, Lee JK, Kim YM, Lee JY, Won MH, Kwon YG. Protein phosphatase 1 nuclear targeting subunit is a hypoxia inducible gene: its role in post-translational modification of p53 and MDM2. Cell Death Differ 2007; 14:1106-16. [PMID: 17318220 DOI: 10.1038/sj.cdd.4402111] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
p53, the most commonly mutated tumor suppressor gene in human cancers, is a master regulator of apoptosis in many types of cells. Recently, protein phosphatase-1 (PP1) has emerged as a key phosphatase of p53, which modulates the interaction of p53 with its regulatory protein mouse double minute 2 (MDM2) and transcriptional activity. In the present study, we demonstrate the potential role of PP1 nuclear targeting subunit (PNUTS) in regulating the phosphorylation and apoptotic activities of p53. Hypoxia significantly increased mRNA and protein expression of PNUTS in various cell lines concomitantly with increases in p53. Promoter analysis confirmed the presence of hypoxia response elements in the promoter region of the PNUTS gene, which respond to hypoxia and forced expression of hypoxia-inducible factor 1 alpha. Overexpression of PNUTS markedly increased cell death in response to hypoxia, with increased expression of Bax, an apoptosis-related gene induced by p53. Consistently, PNUTS increased the nuclear localization, phosphorylation, and transcriptional activity of p53 as well as the ubiquitin-dependent proteosomal degradation of MDM2. However, the W401A mutant form of PNUTS, which is incapable of binding to PP1, failed to induce these events. Taken together, our findings suggest that PNUTS may play an important role in controlling cell death in response to cellular stresses such as hypoxia through the post-translational modification of p53 and MDM2.
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Affiliation(s)
- S-J Lee
- Department of Biochemistry, College of Sciences, Yonsei University, Shinchon-dong, Seodaemoon-gu, Seoul, Korea
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26
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Guo C, Mi J, Brautigan DL, Larner JM. ATM regulates ionizing radiation-induced disruption of HDAC1:PP1:Rb complexes. Cell Signal 2006; 19:504-10. [PMID: 17008050 DOI: 10.1016/j.cellsig.2006.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 07/11/2006] [Accepted: 08/13/2006] [Indexed: 01/03/2023]
Abstract
Ionizing radiation elicits signaling events that coordinate DNA repair and interruption of cell cycle progression. We previously demonstrated that ionizing radiation (IR) of cells activates nuclear protein phosphatase-1 (PP1) by promoting dephosphorylation of Thr320, an inhibitory site in the enzyme and that the ATM kinase is required for this response. We sought to identify potential targets of IR-activated PP1. Untreated and IR-treated Jurkat cells were labeled with (32)P orthophosphate, and nuclear extracts were subjected to microcystin affinity chromatography to recover phosphatase complexes that were analyzed by 2D-PAGE and mass spectrometry. Several proteins associated with protein phosphatases demonstrated a significant decrease in (32)P intensity following IR, and one of these was identified as HDAC1. Co-immunoprecipitation revealed complexes containing PP1 with HDAC1 and Rb in cell extracts. In response to IR, there was an ATM-dependent activation of PP1, dephosphorylation of HDAC1, dissociation of HDAC1-PP1-Rb complexes and increased HDAC1 activity. These results suggest that IR regulates HDAC1 phosphorylation and activity through ATM-dependent activation of PP1.
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Affiliation(s)
- Changyue Guo
- Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA 22908, United States
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27
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Li DWC, Liu JP, Schmid PC, Schlosser R, Feng H, Liu WB, Yan Q, Gong L, Sun SM, Deng M, Liu Y. Protein serine/threonine phosphatase-1 dephosphorylates p53 at Ser-15 and Ser-37 to modulate its transcriptional and apoptotic activities. Oncogene 2006; 25:3006-22. [PMID: 16501611 DOI: 10.1038/sj.onc.1209334] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We have previously demonstrated that the serine/threonine protein phosphatase-1 (PP-1) plays an important role in promoting cell survival. However, the molecular mechanisms by which PP-1 promotes survival remain largely unknown. In the present study, we provide evidence to show that PP-1 can directly dephosphorylate a master regulator of apoptosis, p53, to negatively modulate its transcriptional and apoptotic activities, and thus to promote cell survival. As a transcriptional factor, the function of p53 can be greatly regulated by phosphorylation and dephosphorylation. While the kinases responsible for phosphorylation of the 17 serine/threonine sites have been identified, the dephosphorylation of these sites remains largely unknown. In the present study, we demonstrate that PP-1 can dephosphorylate p53 at Ser-15 and Ser-37 through co-immunoprecipitation, in vitro and in vivo dephosphorylation assays, overexpression and silence of the gene encoding the catalytic subunit for PP-1. We further show that mutations mimicking constitutive dephosphorylation or phosphorylation of p53 at these sites attenuate or enhance its transcriptional activity, respectively. As a result of the changed p53 activity, expression of the downstream apoptosis-related genes such as bcl-2 and bax is accordingly altered and the apoptotic events are either largely abrogated or enhanced. Thus, our results demonstrate that PP-1 directly dephosphorylates p53, and dephosphorylation of p53 has as important impact on its functions as phosphorylation does. In addition, our results reveal that one of the molecular mechanisms by which PP-1 promotes cell survival is to dephosphorylate p53, and thus negatively regulate p53-dependent death pathway.
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MESH Headings
- Amino Acid Substitution
- Animals
- Apoptosis/drug effects
- Apoptosis/genetics
- Apoptosis/physiology
- Cell Line/drug effects
- Cell Line/enzymology
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Genes, Reporter
- Genes, bcl-2
- Genes, p53
- Humans
- Immunoprecipitation
- Lens, Crystalline/cytology
- Marine Toxins
- Mice
- Mice, Knockout
- Okadaic Acid/pharmacology
- Oxazoles/pharmacology
- Phosphoprotein Phosphatases/antagonists & inhibitors
- Phosphoprotein Phosphatases/genetics
- Phosphoprotein Phosphatases/physiology
- Phosphorylation/drug effects
- Phosphoserine/metabolism
- Protein Binding
- Protein Interaction Mapping
- Protein Phosphatase 1
- Protein Processing, Post-Translational/drug effects
- Protein Processing, Post-Translational/physiology
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- RNA Interference
- RNA, Small Interfering/pharmacology
- Recombinant Fusion Proteins/physiology
- Transcription, Genetic/drug effects
- Transcription, Genetic/physiology
- Tumor Suppressor Protein p53/chemistry
- Tumor Suppressor Protein p53/metabolism
- bcl-2-Associated X Protein/biosynthesis
- bcl-2-Associated X Protein/genetics
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Affiliation(s)
- D W-C Li
- The Hormel Institute, University of Minnesota, Austin, 55912, USA.
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28
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Nery FC, Rui E, Kuniyoshi TM, Kobarg J. Evidence for the interaction of the regulatory protein Ki-1/57 with p53 and its interacting proteins. Biochem Biophys Res Commun 2006; 341:847-55. [PMID: 16455055 DOI: 10.1016/j.bbrc.2006.01.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Accepted: 01/11/2006] [Indexed: 12/15/2022]
Abstract
Ki-1/57 is a cytoplasmic and nuclear phospho-protein of 57 kDa and interacts with the adaptor protein RACK1, the transcription factor MEF2C, and the chromatin remodeling factor CHD3, suggesting that it might be involved in the regulation of transcription. Here, we describe yeast two-hybrid studies that identified a total of 11 proteins interacting with Ki-1/57, all of which interact or are functionally associated with p53 or other members of the p53 family of proteins. We further found that Ki-1/57 is able to interact with p53 itself in the yeast two-hybrid system when the interaction was tested directly. This interaction could be confirmed by pull down assays with purified proteins in vitro and by reciprocal co-immunoprecipitation assays from the human Hodgkin analogous lymphoma cell line L540. Furthermore, we found that the phosphorylation of p53 by PKC abolishes its interaction with Ki-1/57 in vitro.
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Affiliation(s)
- Flávia C Nery
- Centro de Biologia Molecular Estrutural, Laboratório Nacional de Luz Síncrotron, Rua Giuseppe Máximo Scolfaro 10.000, C.P. 6192, 13084-971 Campinas, SP, Brazil
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Fu WY, Xu LH, Yu YN. Proteomic Analysis of Cellular Response to Microcystin in Human Amnion FL Cells. J Proteome Res 2005; 4:2207-15. [PMID: 16335968 DOI: 10.1021/pr050325k] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Microcystins (MC), the potent inhibitor of protein phosphatase 1 and 2A, are hepatotoxins of increasing importance due to its high acute toxicity and potent tumor promoting activity. So far, the exact mechanisms of MC-induced hepatotoxicity and tumor promoting activity have not been fully elucidated. To better understand the mechanisms underlying microcystin-RR (MC-RR) induced toxicity as well as provide the possibility for the establishment of biomarkers for MC-RR exposure, differential proteome analysis on human amnion FL cells treated by MC-RR was carried out using two-dimensional gel electrophoresis (2-DE) followed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Image analysis of silver-stained 2-dimensional gels revealed that 89 proteins showed significant differential expression in MC-RR treated cells compared with control, and 8 proteins were unique to MC-RR treated cells and 8 proteins were only detected in control cells. Sixty-six proteins were further identified with high confidence by peptide mass fingerprinting. Some of the identified differentially expressed proteins have clearly relationship with the process of apoptosis, signal transduction, and cytoskeleton alteration which are consistent with the literature. The functional implications of alterations in the levels of these proteins were discussed. However, most of which have not been reported previously to be involved in cellular processes responded to MC-RR. Therefore, this work will provide new insight into the mechanism of MC-RR toxicity.
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Affiliation(s)
- Wen-yu Fu
- Department of Biochemistry and Molecular Biology, Zhejiang University, School of Medicine, Hangzhou, China
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Abstract
Interest in the tumour suppressor p53 has generated much information regarding the complexity of its function and regulation in carcinogenesis. However, gaps still exist in our knowledge regarding the role of p53 post-translational modifications in carcinogenesis and cancer prevention. A thorough understanding of p53 will be extremely useful in the development of new strategies for treating and preventing cancer, including restoration of p53 function and selective killing of tumours with mutant TP53.
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Affiliation(s)
- Ann M Bode
- The Hormel Institute, University of Minnesota, 801 16th Avenue NE, Austin, Minnesota 55912, USA
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