1
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Ando S, Tanaka K, Matsumoto M, Oyama Y, Tomabechi Y, Yamagata A, Shirouzu M, Nakagawa R, Okimoto N, Taiji M, Sato K, Ohama T. The luciferase-based in vivo protein-protein interaction assay revealed that CHK1 promotes PP2A and PME-1 interaction. J Biol Chem 2024; 300:107277. [PMID: 38588804 PMCID: PMC11098961 DOI: 10.1016/j.jbc.2024.107277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/12/2024] [Accepted: 04/02/2024] [Indexed: 04/10/2024] Open
Abstract
Protein phosphatase 2A (PP2A) is an essential serine/threonine protein phosphatase, and its dysfunction is involved in the onset of cancer and neurodegenerative disorders. PP2A functions as a trimeric holoenzyme whose composition is regulated by the methyl-esterification (methylation) of the PP2A catalytic subunit (PP2Ac). Protein phosphatase methylesterase-1 (PME-1) is the sole PP2Ac methylesterase, and the higher PME-1 expression is observed in various cancer and neurodegenerative diseases. Apart from serving as a methylesterase, PME-1 acts as a PP2A inhibitory protein, binding directly to PP2Ac and suppressing its activity. The intricate function of PME-1 hinders drug development by targeting the PME-1/PP2Ac axis. This study applied the NanoBiT system, a bioluminescence-based protein interaction assay, to elucidate the molecular mechanism that modulates unknown PME-1/PP2Ac protein-protein interaction (PPI). Compound screening identified that the CHK1 inhibitors inhibited PME-1/PP2Ac association without affecting PP2Ac methylation levels. CHK1 directly phosphorylates PP2Ac to promote PME-1 association. Phospho-mass spectrometry identified multiple phospho-sites on PP2Ac, including the Thr219, that affect PME-1 interaction. An anti-phospho-Thr219 PP2Ac antibody was generated and showed that CHK1 regulates the phosphorylation levels of this site in cells. On the contrary, in vitro phosphatase assay showed that CHK1 is the substrate of PP2A, and PME-1 hindered PP2A-mediated dephosphorylation of CHK1. Our data provides novel insights into the molecular mechanisms governing the PME-1/PP2Ac PPI and the triad relationship between PP2A, PME-1, and CHK1.
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Affiliation(s)
- Sana Ando
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Keiko Tanaka
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Maharu Matsumoto
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Yuki Oyama
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Yuri Tomabechi
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | - Atsushi Yamagata
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | - Mikako Shirouzu
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | - Reiko Nakagawa
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | - Noriaki Okimoto
- Laboratory for Computational Molecular Design, RIKEN Center for Biosystems Dynamics Research (BDR), Osaka, Japan; Drug Discovery Molecular Simulation Platform Unit, RIKEN Center for Biosystems Dynamics Research (BDR), Osaka, Japan
| | - Makoto Taiji
- Laboratory for Computational Molecular Design, RIKEN Center for Biosystems Dynamics Research (BDR), Osaka, Japan; Drug Discovery Molecular Simulation Platform Unit, RIKEN Center for Biosystems Dynamics Research (BDR), Osaka, Japan
| | - Koichi Sato
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan; Research Institute for Cell Design Medical Science, Yamaguchi University, Yamaguchi, Japan
| | - Takashi Ohama
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan; Research Institute for Cell Design Medical Science, Yamaguchi University, Yamaguchi, Japan.
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2
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Ikeda S, Sato K, Ohama T. Transcriptome analysis revealed that PME-1 suppresses inflammatory signaling, activates PI3K/Akt signaling, and promotes epithelial-mesenchymal transition. Biochem Biophys Res Commun 2024; 692:149148. [PMID: 38043157 DOI: 10.1016/j.bbrc.2023.149148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 09/28/2023] [Accepted: 10/23/2023] [Indexed: 12/05/2023]
Abstract
Protein phosphatase 2A (PP2A) is an essential serine/threonine protein phosphatase that belongs to the type2A protein phosphatase family with PP4 and PP6. PP2A functions as a trimeric holoenzyme, and the composition of the trimer is regulated by the methyl-esterification (methylation) of PP2A. Demethylation of PP2A is catalyzed by protein phosphatase methyl-esterase-1 (PME-1). Despite the physiological and pathophysiological importance of PME-1, the impact of changes in PME-1 expression on the transcriptome has not been reported. This study provides transcriptome data to gain a comprehensive understanding of the effects of PME-1 knockout on intracellular signaling of mouse embryonic fibroblasts. Our data showed that PME-1 suppresses inflammatory signaling, activates PI3K/Akt signaling, and promotes epithelial-mesenchymal transition.
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Affiliation(s)
- Shunta Ikeda
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Koichi Sato
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Takashi Ohama
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan.
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3
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Guffens L, Derua R, Janssens V. PME-1 sensitizes glioblastoma cells to oxidative stress-induced cell death by attenuating PP2A-B55α-mediated inactivation of MAPKAPK2-RIPK1 signaling. Cell Death Discov 2023; 9:265. [PMID: 37500619 PMCID: PMC10374899 DOI: 10.1038/s41420-023-01572-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/13/2023] [Accepted: 07/20/2023] [Indexed: 07/29/2023] Open
Abstract
Glioblastoma (GBM) is the most common primary brain tumor in adults. Current standard therapy is surgery followed by radiotherapy, with concurrent and adjuvant temozolomide chemotherapy. GBM is characterized by almost uniformly fatal outcomes, highlighting the unmet clinical need for more efficient, biomarker-guided treatments. Protein phosphatase methylesterase-1 (PME-1), a regulator of the tumor suppressive phosphatase PP2A, promotes PP2A demethylation and inactivation, and is overexpressed in 44% of GBM, associated with increased tumor grade and cellular proliferation. Here, we aimed to investigate how reactive oxygen species (ROS), a frequent by-product of radiotherapy and temozolomide chemotherapy, regulate PP2A function via its methylesterase PME-1, and how PME-1 overexpression impacts the response of GBM cells to oxidative stress. We found that in two glioblastoma cell lines, U87MG and U251MG, expression of PME-1 is positively correlated with the sensitivity of the cells to H2O2 or t-BHP-induced oxidative stress. Experiments using the irreversible pharmacologic PME-1 inhibitor, AMZ30, and different PME-1 mutants, revealed that the methylesterase function, the PP2A binding capacity, and the nuclear localization of PME-1 are all important for the sensitizing effect of PME-1 expression. Furthermore, we identified increased nuclear localization of the PP2A-B55α subunit, increased binding of PP2A-B55α to PME-1, and increased B55α-bound PP2A-C demethylation upon oxidative stress. Lastly, we uncovered increased stress-induced phosphorylation and activity of MAPKAPK2 and RIPK1 in PME-1 overexpressing U87MG cells, which caused the observed sensitization to t-BHP treatment. Our data reveal a novel role for PME-1 in oxidative stress-induced GBM cell death, regulating nuclear PP2A-B55α activity and MAPKAPK2-RIPK1 signaling. Patients with GBM tumors overexpressing PME-1, although having a worse prognosis due to increased cellular proliferation of the tumor, could actually be more responsive to oxidative stress-inducing therapies.
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Affiliation(s)
- Liesbeth Guffens
- Laboratory of Protein Phosphorylation & Proteomics, Dept. Cellular & Molecular Medicine, KU Leuven, B-3000, Leuven, Belgium
- KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium
| | - Rita Derua
- Laboratory of Protein Phosphorylation & Proteomics, Dept. Cellular & Molecular Medicine, KU Leuven, B-3000, Leuven, Belgium
- SyBioMa, KU Leuven, B-3000, Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Dept. Cellular & Molecular Medicine, KU Leuven, B-3000, Leuven, Belgium.
- KU Leuven Cancer Institute (LKI), B-3000, Leuven, Belgium.
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4
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Arribas RL, Viejo L, Bravo I, Martínez M, Ramos E, Romero A, García-Frutos EM, Janssens V, Montiel C, de Los Ríos C. C-glycosides analogues of the okadaic acid central fragment exert neuroprotection via restoration of PP2A-phosphatase activity: A rational design of potential drugs for Alzheimer's disease targeting tauopathies. Eur J Med Chem 2023; 251:115245. [PMID: 36905916 DOI: 10.1016/j.ejmech.2023.115245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/24/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023]
Abstract
Protein phosphatase 2A (PP2A) is an important Ser/Thr phosphatase that participates in the regulation of multiple cellular processes. This implies that any deficient activity of PP2A is the responsible of severe pathologies. For instance, one of the main histopathological features of Alzheimer's disease is neurofibrillary tangles, which are mainly comprised by hyperphosphorylated forms of tau protein. This altered rate of tau phosphorylation has been correlated with PP2A depression AD patients. With the goal of preventing PP2A inactivation in neurodegeneration scenarios, we have aimed to design, synthesize and evaluate new ligands of PP2A capable of preventing its inhibition. To achieve this goal, the new PP2A ligands present structural similarities with the central fragment C19-C27 of the well-established PP2A inhibitor okadaic acid (OA). Indeed, this central moiety of OA does not exert inhibitory actions. Hence, these compounds lack PP2A-inhibiting structural motifs but, in contrast, compete with PP2A inhibitors, thus recovering phosphatase activity. Proving this hypothesis, most compounds showed a good neuroprotective profile in neurodegeneration models related to PP2A impairment, highlighting derivative 10, named ITH12711, as the most promising one. This compound (1) restored in vitro and cellular PP2A catalytic activity, measured on a phospho-peptide substrate and by western-blot analyses, (2) proved good brain penetration measured by PAMPA, and (3) prevented LPS-induced memory impairment of mice in the object recognition test. Thus, the promising outcomes of the compound 10 validate our rational approach to design new PP2A-activating drugs based on OA central fragment.
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Affiliation(s)
- Raquel L Arribas
- Instituto-Fundación Teófilo Hernando, Universidad Autónoma de Madrid, 28029, Madrid, Spain; Departamento de Ciencias Básicas de la Salud, Universidad Rey Juan Carlos, 28922, Alcorcón, Spain
| | - Lucía Viejo
- Instituto-Fundación Teófilo Hernando, Universidad Autónoma de Madrid, 28029, Madrid, Spain; Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, C/ Diego de León, 62, 28006, Madrid, Spain
| | - Isaac Bravo
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, C/ Diego de León, 62, 28006, Madrid, Spain; Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, 28049, Madrid, Spain
| | - Minerva Martínez
- Instituto-Fundación Teófilo Hernando, Universidad Autónoma de Madrid, 28029, Madrid, Spain
| | - Eva Ramos
- Departamento de Farmacología y Toxicología, Facultad de Veterinaria, Universidad Complutense, 28040, Madrid, Spain
| | - Alejandro Romero
- Departamento de Farmacología y Toxicología, Facultad de Veterinaria, Universidad Complutense, 28040, Madrid, Spain
| | - Eva M García-Frutos
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, 28049, Madrid, Spain; Universidad de Alcalá, Departamento de Química Orgánica y Química Inorgánica, Ctra. Madrid-Barcelona Km.33,600, 28871, Alcalá de Henares, Madrid, Spain
| | - Veerle Janssens
- Department of Cellular & Molecular Medicine, Laboratory of Protein Phosphorylation and Proteomics, KU Leuven, B-3000, Leuven, Belgium; LBI (KU Leuven Brain Institute), B-3000, Leuven, Belgium
| | - Carmen Montiel
- Instituto-Fundación Teófilo Hernando, Universidad Autónoma de Madrid, 28029, Madrid, Spain
| | - Cristóbal de Los Ríos
- Instituto-Fundación Teófilo Hernando, Universidad Autónoma de Madrid, 28029, Madrid, Spain; Departamento de Ciencias Básicas de la Salud, Universidad Rey Juan Carlos, 28922, Alcorcón, Spain; Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, C/ Diego de León, 62, 28006, Madrid, Spain.
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5
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Haanen TJ, O'Connor CM, Narla G. Biased holoenzyme assembly of protein phosphatase 2A (PP2A): From cancer to small molecules. J Biol Chem 2022; 298:102656. [PMID: 36328247 PMCID: PMC9707111 DOI: 10.1016/j.jbc.2022.102656] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/25/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a family of serine threonine phosphatases responsible for regulating protein phosphorylation, thus opposing the activity of cellular kinases. PP2A is composed of a catalytic subunit (PP2A Cα/β) and scaffolding subunit (PP2A Aα/β) and various substrate-directing B regulatory subunits. PP2A biogenesis is regulated at multiple levels. For example, the sequestration of the free catalytic subunit during the process of biogenesis avoids promiscuous phosphatase activity. Posttranslational modifications of PP2A C direct PP2A heterotrimeric formation. Additionally, PP2A functions as a haploinsufficient tumor suppressor, where attenuated PP2A enzymatic activity creates a permissive environment for oncogenic transformation. Recent work studying PP2A in cancer showed that its role in tumorigenesis is more nuanced, with some holoenzymes being tumor suppressive, while others are required for oncogenic transformation. In cancer biology, PP2A function is modulated through various mechanisms including the displacement of specific B regulatory subunits by DNA tumor viral antigens, by recurrent mutations, and through loss of carboxymethyl-sensitive heterotrimeric complexes. In aggregate, these alterations bias PP2A activity away from its tumor suppressive functions and toward oncogenic ones. From a therapeutic perspective, molecular glues and disruptors present opportunities for both the selective stabilization of tumor-suppressive holoenzymes and disruption of holoenzymes that are pro-oncogenic. Collectively, these approaches represent an attractive cancer therapy for a wide range of tumor types. This review will discuss the mechanisms by which PP2A holoenzyme formation is dysregulated in cancer and the current therapies that are aimed at biasing heterotrimer formation of PP2A for the treatment of cancer.
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6
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Kokot T, Köhn M. Emerging insights into serine/threonine-specific phosphoprotein phosphatase function and selectivity. J Cell Sci 2022; 135:277104. [DOI: 10.1242/jcs.259618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
ABSTRACT
Protein phosphorylation on serine and threonine residues is a widely distributed post-translational modification on proteins that acts to regulate their function. Phosphoprotein phosphatases (PPPs) contribute significantly to a plethora of cellular functions through the accurate dephosphorylation of phosphorylated residues. Most PPPs accomplish their purpose through the formation of complex holoenzymes composed of a catalytic subunit with various regulatory subunits. PPP holoenzymes then bind and dephosphorylate substrates in a highly specific manner. Despite the high prevalence of PPPs and their important role for cellular function, their mechanisms of action in the cell are still not well understood. Nevertheless, substantial experimental advancements in (phospho-)proteomics, structural and computational biology have contributed significantly to a better understanding of PPP biology in recent years. This Review focuses on recent approaches and provides an overview of substantial new insights into the complex mechanism of PPP holoenzyme regulation and substrate selectivity.
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Affiliation(s)
- Thomas Kokot
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg 1 , Freiburg 79104 , Germany
- University of Freiburg, 2 Faculty of Biology , Freiburg 79104 , Germany
| | - Maja Köhn
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg 1 , Freiburg 79104 , Germany
- University of Freiburg, 2 Faculty of Biology , Freiburg 79104 , Germany
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7
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Li Y, Balakrishnan VK, Rowse M, Wu CG, Bravos AP, Yadav VK, Ivarsson YI, Strack S, Novikova IV, Xing Y. Coupling to short linear motifs creates versatile PME-1 activities in PP2A holoenzyme demethylation and inhibition. eLife 2022; 11:79736. [PMID: 35924897 PMCID: PMC9398451 DOI: 10.7554/elife.79736] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/03/2022] [Indexed: 11/30/2022] Open
Abstract
Protein phosphatase 2A (PP2A) holoenzymes target broad substrates by recognizing short motifs via regulatory subunits. PP2A methylesterase 1 (PME-1) is a cancer-promoting enzyme and undergoes methylesterase activation upon binding to the PP2A core enzyme. Here, we showed that PME-1 readily demethylates different families of PP2A holoenzymes and blocks substrate recognition in vitro. The high-resolution cryoelectron microscopy structure of a PP2A-B56 holoenzyme–PME-1 complex reveals that PME-1 disordered regions, including a substrate-mimicking motif, tether to the B56 regulatory subunit at remote sites. They occupy the holoenzyme substrate-binding groove and allow large structural shifts in both holoenzyme and PME-1 to enable multipartite contacts at structured cores to activate the methylesterase. B56 interface mutations selectively block PME-1 activity toward PP2A-B56 holoenzymes and affect the methylation of a fraction of total cellular PP2A. The B56 interface mutations allow us to uncover B56-specific PME-1 functions in p53 signaling. Our studies reveal multiple mechanisms of PME-1 in suppressing holoenzyme functions and versatile PME-1 activities derived from coupling substrate-mimicking motifs to dynamic structured cores.
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Affiliation(s)
- Yitong Li
- Department of Oncology, University of Wisconsin-Madison, Madison, United States
| | | | - Michael Rowse
- Indiana University - Purdue University Columbus, Columbus, United States
| | - Cheng-Guo Wu
- Department of Oncology, University of Wisconsin-Madison, Madison, United States
| | | | - Vikash K Yadav
- 5Department of Chemistry, Uppsala University, Uppsala, Sweden
| | - YIva Ivarsson
- 5Department of Chemistry, Uppsala University, Uppsala, Sweden
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, United States
| | - Irina V Novikova
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, United States
| | - Yongna Xing
- Department of Oncology, University of Wisconsin-Madison, Madison, United States
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8
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Chen N, Tang J, Su Q, Chou WC, Zheng F, Guo Z, Yu G, Shao W, Li H, Wu S. Paraquat-induced oxidative stress regulates N6-methyladenosine (m 6A) modification of circular RNAs. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 290:117816. [PMID: 34425375 DOI: 10.1016/j.envpol.2021.117816] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 07/16/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Paraquat (PQ), a widely used herbicide and well-known oxidative stress inducer, has been linked to numerous neurodegenerative diseases, but the underlying mechanism(s) remains unknown. Circular RNAs (circRNAs) have recently been reported to be associated with oxidative stress in Parkinson's disease. Herein, we performed methylated RNA immunoprecipitation and RNA sequencing assays for mouse neuroblastoma (Neuro-2a) cells and successfully established a positive link between the alteration of circRNAs driven by m6A modification and PQ-induced oxidative stress. We observed oxidative stress and antioxidative stress present distinct m6A modification pattern of circRNAs as well as biological effect. Gene ontology and pathway analysis predicted that differentially m6A-methylated and expressed circRNAs are highly clustered in pathways associated with function and development of nervous system, including axon cargo transport, nervous system development, long-term potentiation, and neurotrophic signaling pathways. Moreover, we demonstrated that the alteration of m6A-methylated circRNAs upon PQ exposure could be partially reversed by N-acetylcysteine pretreatment. The mechanistic analysis further demonstrated that N-acetylcysteine pretreatment attenuated the decreased expression of target genes (UBC and PPP2CA) induced by PQ. These findings revealed distinct patterns of differentially m6A-modified circRNAs, indicating that m6A could participate in a specific regulatory network of circRNAs to modulate the expression of downstream genes in response to PQ-induced oxidative stress. In conclusion, our work established a link between m6A modification of circRNAs and PQ-induced oxidative stress, and further studies are required to explore the underlying molecular mechanisms associated with PQ-induced neurotoxicity.
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Affiliation(s)
- Nengzhou Chen
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, 350122, China
| | - Jianping Tang
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, 350122, China
| | - Qianqian Su
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, 350122, China
| | - Wei-Chun Chou
- Institute of Computational Comparative Medicine (ICCM), Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, United States
| | - Fuli Zheng
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, 350122, China
| | - Zhenkun Guo
- The Key Laboratory of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou, 350122, China; Fujian Provincial Key Laboratory of Environment Factors and Cancer, School of Public Health, Fujian Medical University, Fuzhou, 350122, China
| | - Guangxia Yu
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, 350122, China
| | - Wenya Shao
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, 350122, China
| | - Huangyuan Li
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, 350122, China; The Key Laboratory of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou, 350122, China; Fujian Provincial Key Laboratory of Environment Factors and Cancer, School of Public Health, Fujian Medical University, Fuzhou, 350122, China
| | - Siying Wu
- Department of Epidemiology and Health Statistics, School of Public Health, Fujian Medical University, Fuzhou, 350122, China; Fujian Provincial Key Laboratory of Environment Factors and Cancer, School of Public Health, Fujian Medical University, Fuzhou, 350122, China.
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9
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Lyons SP, Greiner EC, Cressey LE, Adamo ME, Kettenbach AN. Regulation of PP2A, PP4, and PP6 holoenzyme assembly by carboxyl-terminal methylation. Sci Rep 2021; 11:23031. [PMID: 34845248 PMCID: PMC8630191 DOI: 10.1038/s41598-021-02456-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 11/15/2021] [Indexed: 12/16/2022] Open
Abstract
The family of Phosphoprotein Phosphatases (PPPs) is responsible for most cellular serine and threonine dephosphorylation. PPPs achieve substrate specificity and selectivity by forming multimeric holoenzymes. PPP holoenzyme assembly is tightly controlled, and changes in the cellular repertoire of PPPs are linked to human disease, including cancer and neurodegeneration. For PP2A, PP4, and PP6, holoenzyme formation is in part regulated by carboxyl (C)-terminal methyl-esterification (often referred to as "methylation"). Here, we use mass spectrometry-based proteomics, methylation-ablating mutations, and genome editing to elucidate the role of C-terminal methylation on PP2A, PP4, and PP6 holoenzyme assembly. We find that the catalytic subunits of PP2A, PP4, and PP6 are frequently methylated in cancer cells and that deletion of the C-terminal leucine faithfully recapitulates loss of methylation. We observe that loss of PP2A methylation consistently reduced B55, B56, and B72 regulatory subunit binding in cancer and non-transformed cell lines. However, Striatin subunit binding is only affected in non-transformed cells. For PP4, we find that PP4R1 and PP4R3β bind in a methylation-dependent manner. Intriguingly, loss of methylation does not affect PP6 holoenzymes. Our analyses demonstrate in an unbiased, comprehensive, and isoform-specific manner the crucial regulatory function of endogenous PPP methylation in transformed and non-transformed cell lines.
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Affiliation(s)
- Scott P Lyons
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | | | | | | | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
- Norris Cotton Cancer Center, Lebanon, NH, USA.
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10
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Hollenstein DM, Gérecová G, Romanov N, Ferrari J, Veis J, Janschitz M, Beyer R, Schüller C, Ogris E, Hartl M, Ammerer G, Reiter W. A phosphatase-centric mechanism drives stress signaling response. EMBO Rep 2021; 22:e52476. [PMID: 34558777 PMCID: PMC8567219 DOI: 10.15252/embr.202152476] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 08/27/2021] [Accepted: 09/03/2021] [Indexed: 12/14/2022] Open
Abstract
Changing environmental cues lead to the adjustment of cellular physiology by phosphorylation signaling networks that typically center around kinases as active effectors and phosphatases as antagonistic elements. Here, we report a signaling mechanism that reverses this principle. Using the hyperosmotic stress response in Saccharomyces cerevisiae as a model system, we find that a phosphatase-driven mechanism causes induction of phosphorylation. The key activating step that triggers this phospho-proteomic response is the Endosulfine-mediated inhibition of protein phosphatase 2A-Cdc55 (PP2ACdc55 ), while we do not observe concurrent kinase activation. In fact, many of the stress-induced phosphorylation sites appear to be direct substrates of the phosphatase, rendering PP2ACdc55 the main downstream effector of a signaling response that operates in parallel and independent of the well-established kinase-centric stress signaling pathways. This response affects multiple cellular processes and is required for stress survival. Our results demonstrate how a phosphatase can assume the role of active downstream effectors during signaling and allow re-evaluating the impact of phosphatases on shaping the phosphorylome.
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Affiliation(s)
- David Maria Hollenstein
- Department of Biochemistry and Cell BiologyMax Perutz LabsVienna BioCenter (VBC)University of ViennaViennaAustria
| | - Gabriela Gérecová
- Department of Biochemistry and Cell BiologyMax Perutz LabsVienna BioCenter (VBC)University of ViennaViennaAustria
| | | | - Jessica Ferrari
- Department of Biochemistry and Cell BiologyMax Perutz LabsVienna BioCenter (VBC)University of ViennaViennaAustria
| | - Jiri Veis
- Department of Biochemistry and Cell BiologyMax Perutz LabsVienna BioCenter (VBC)University of ViennaViennaAustria
- Center for Medical BiochemistryMax Perutz Labs, Vienna BioCenterMedical University of ViennaViennaAustria
| | - Marion Janschitz
- Department of Biochemistry and Cell BiologyMax Perutz LabsVienna BioCenter (VBC)University of ViennaViennaAustria
| | - Reinhard Beyer
- Department of Applied Genetics and Cell Biology (DAGZ)University of Natural Resources and Life Sciences (BOKU)ViennaAustria
- Research Platform Bioactive Microbial Metabolites (BiMM)Tulln a.d. DonauAustria
| | - Christoph Schüller
- Department of Applied Genetics and Cell Biology (DAGZ)University of Natural Resources and Life Sciences (BOKU)ViennaAustria
- Research Platform Bioactive Microbial Metabolites (BiMM)Tulln a.d. DonauAustria
| | - Egon Ogris
- Center for Medical BiochemistryMax Perutz Labs, Vienna BioCenterMedical University of ViennaViennaAustria
| | - Markus Hartl
- Department of Biochemistry and Cell BiologyMax Perutz LabsVienna BioCenter (VBC)University of ViennaViennaAustria
- Mass Spectrometry FacilityMax Perutz Labs, Vienna BioCenterUniversity of ViennaViennaAustria
| | - Gustav Ammerer
- Department of Biochemistry and Cell BiologyMax Perutz LabsVienna BioCenter (VBC)University of ViennaViennaAustria
| | - Wolfgang Reiter
- Department of Biochemistry and Cell BiologyMax Perutz LabsVienna BioCenter (VBC)University of ViennaViennaAustria
- Mass Spectrometry FacilityMax Perutz Labs, Vienna BioCenterUniversity of ViennaViennaAustria
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11
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Xu Y, Wei L, Tang S, Shi Q, Wu B, Yang X, Zou Y, Wang X, Ao Q, Meng L, Wei X, Zhang N, Li Y, Lan C, Chen M, Li X, Lu C. Regulation PP2Ac methylation ameliorating autophagy dysfunction caused by Mn is associated with mTORC1/ULK1 pathway. Food Chem Toxicol 2021; 156:112441. [PMID: 34363881 DOI: 10.1016/j.fct.2021.112441] [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: 02/05/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 01/18/2023]
Abstract
Manganese (Mn) exposure leads to autophagy dysfunction and causes neurodegenerative diseases such as Parkinson's syndrome and Alzheimer's disease. However, the mechanism of neurotoxicity of Mn has been less clear. The methylation of the protein phosphatase 2A catalytic subunit determines the dephosphorylation activity of protein phosphatase and plays an important role in autophagy regulation. In this investigation, we established a model of Mn (0-2000 μmol/L) exposure to N2a cells for 12 h, used the PPME-1 inhibitor ABL-127, and constructed an LCMT1-overexpressing N2a cell line. We also regulated the PP2Ac methylation level and explored the effect of PP2Ac methylation on Mn-induced (0-1000 μmol/L) N2a cellular autophagy. Our results showed that Mn > 500 μmol/L induced N2a cell damage and increased oxidative stress. Moreover, Mn modulated autophagy in N2a cells by downregulating PP2Ac methylation, which regulated mTORC1 signaling pathway activation. Both ABL-127 and LCMT1 overexpression can upregulate PP2Ac methylation in parallel with ameliorating N2a cell abnormal autophagy induced by Mn, Briefly, the upregulation of PP2Ac methylation can ameliorate the autophagy disorder of N2a by Mn and effectively alleviate Mn-induced cytotoxicity and oxidative stress, indicating that regulation of autophagy is a protective strategy against Mn-induced neurotoxicity.
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Affiliation(s)
- Yilu Xu
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Lancheng Wei
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Shen Tang
- School of Preclinical Medicine, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Preclinical Medicine, Nanning, 530021, China
| | - Qianqian Shi
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Bin Wu
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Xiaobo Yang
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Yunfeng Zou
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Xinhang Wang
- School of Preclinical Medicine, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Preclinical Medicine, Nanning, 530021, China
| | - Qingqing Ao
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Ling Meng
- School of Preclinical Medicine, Guangxi Medical University, Nanning, 530021, China
| | - Xuejing Wei
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Ning Zhang
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Yunqing Li
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Chunhua Lan
- School of Preclinical Medicine, Guangxi Medical University, Nanning, 530021, China
| | - Muting Chen
- School of Public Health, Guangxi Medical University, Nanning, 530021, China
| | - Xiyi Li
- School of Public Health, Guangxi Medical University, Nanning, 530021, China.
| | - Cailing Lu
- School of Public Health, Guangxi Medical University, Nanning, 530021, China.
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12
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Ikeda S, Tsuji S, Ohama T, Sato K. Involvement of PP2A methylation in the adipogenic differentiation of bone marrow-derived mesenchymal stem cell. J Biochem 2021; 168:643-650. [PMID: 32663263 DOI: 10.1093/jb/mvaa077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 06/20/2020] [Accepted: 07/06/2020] [Indexed: 12/12/2022] Open
Abstract
Bone marrow-derived mesenchymal stem cells (BM-MSCs) are multipotent stem cells with ability to self-replicate and differentiate into mesodermal derivatives, such as adipocytes and osteoblasts. BM-MSCs are a critical component of the tumour microenvironment. They support tumour progression by recruiting additional BM-MSCs and by differentiating into myofibroblasts (also called cancer-associated fibroblasts). Protein phosphatase 2A (PP2A) is an essential serine/threonine protein phosphatase that regulates a broad range of cellular signalling. PP2A forms a heterotrimer to dephosphorylate specific substrates. The reversible methylesterification (methylation) of Leu309 in the catalytic subunit of PP2A (PP2Ac) regulates biogenesis of the PP2A holoenzyme. It is unknown whether the methylation of PP2Ac plays a role in BM-MSC differentiation. Our experiments determined that protein levels of PP2A subunits and PP2A methyltransferase (LCMT-1) are significantly altered during differentiation. PP2Ac methylation levels in BM-MSCs decrease over time in response to an adipogenic differentiation stimulus. However, blockage of PP2A demethylation using the PP2A dimethyl-esterase inhibitors enhanced adipocyte differentiation. This suggests that PP2Ac demethylation is involved in adipocyte differentiation resistance. The results of our study provide a greater understanding of the regulation of BM-MSCs differentiation by PP2A holoenzyme.
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Affiliation(s)
- Shunta Ikeda
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Shunya Tsuji
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Takashi Ohama
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Koichi Sato
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
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13
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Frohner IE, Mudrak I, Schüchner S, Anrather D, Hartl M, Sontag JM, Sontag E, Wadzinski BE, Preglej T, Ellmeier W, Ogris E. PP2A C Phospho-Tyr 307 Antibodies Are Not Specific for this Modification but Are Sensitive to Other PP2A C Modifications Including Leu 309 Methylation. Cell Rep 2021; 30:3171-3182.e6. [PMID: 32130916 DOI: 10.1016/j.celrep.2020.02.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/03/2019] [Accepted: 02/07/2020] [Indexed: 02/06/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is an important regulator of signal transduction pathways and a tumor suppressor. Phosphorylation of the PP2A catalytic subunit (PP2AC) at tyrosine 307 has been claimed to inactivate PP2A and was examined in more than 180 studies using commercial antibodies, but this modification was never identified using mass spectrometry. Here we show that the most cited pTyr307 monoclonal antibodies, E155 and F-8, are not specific for phosphorylated Tyr307 but instead are hampered by PP2AC methylation at leucine 309 or phosphorylation at threonine 304. Other pTyr307 antibodies are sensitive to PP2AC methylation as well, and some cross-react with pTyr residues in general, including phosphorylated hemagglutinin tags. We identify pTyr307 using targeted mass spectrometry after transient overexpression of PP2AC and Src kinase. Yet under such conditions, none of the tested antibodies show exclusive pTyr307 specificity. Thus, data generated using these antibodies need to be revisited, and the mechanism of PP2A inactivation needs to be redefined.
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Affiliation(s)
- Ingrid E Frohner
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Ingrid Mudrak
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Stefan Schüchner
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Dorothea Anrather
- Mass Spectrometry Facility, Max Perutz Labs, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Markus Hartl
- Mass Spectrometry Facility, Max Perutz Labs, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Jean-Marie Sontag
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Estelle Sontag
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Brian E Wadzinski
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Teresa Preglej
- Division of Immunobiology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Wilfried Ellmeier
- Division of Immunobiology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Egon Ogris
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
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14
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Fujimoto T, Tsunedomi R, Matsukuma S, Yoshimura K, Oga A, Fujiwara N, Fujiwara Y, Matsui H, Shindo Y, Tokumitsu Y, Suzuki N, Kobayashi S, Hazama S, Eguchi H, Nagano H. Cathepsin B is highly expressed in pancreatic cancer stem-like cells and is associated with patients' surgical outcomes. Oncol Lett 2020; 21:30. [PMID: 33240436 PMCID: PMC7681200 DOI: 10.3892/ol.2020.12291] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 09/15/2020] [Indexed: 12/12/2022] Open
Abstract
Cancer stem-like cells (CSLCs) in solid tumors are resistant to conventional chemotherapy and molecularly targeted therapy, which is thought to contribute to cancer recurrence and metastasis. The present study aimed to identify biomarkers for pancreatic CSLCs (P-CSLCs). Using our previously reported methods, P-CSLC-enriched populations were generated from pancreatic cancer cell lines. The protein expression profiles of these populations were compared with those of parental cells using two-dimensional electrophoresis, tandem mass spectrometry, flow cytometry and immunohistochemistry. Protein expression in surgical specimens was also evaluated for relationships with clinical outcomes. A lysosomal cysteine protease, cathepsin B (CTSB), was significantly upregulated in P-CSLCs compared with that in the parental cells, as shown using western blotting. Flow cytometry analysis also confirmed that CTSB was more highly expressed on the surface of P-CSLCs compared with that on parental cells. Moreover, PCLCs had elevated cellular secretions of CTSB compared with the parental cells. Finally, CTSB expression was evaluated in 69 resected tumor specimens, and high expression was associated with the patients' clinicopathological features and surgical outcomes. The present results suggested that CTSB is a biomarker for poor survival in patients with pancreatic cancer, which is possibly associated with P-CSLCs. This novel biomarker may also have potential as a therapeutic target.
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Affiliation(s)
- Takuya Fujimoto
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Ryouichi Tsunedomi
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Satoshi Matsukuma
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Kiyoshi Yoshimura
- Department of Clinical Research in Tumor Immunology, Showa University Clinical Research Institute for Clinical Pharmacology and Therapeutics, Setagaya, Tokyo 157-8577, Japan
| | - Atsunori Oga
- Department of Molecular Pathology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Nobuyuki Fujiwara
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Yasuhiro Fujiwara
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Hiroto Matsui
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Yoshitaro Shindo
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Yukio Tokumitsu
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Nobuaki Suzuki
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Shogo Kobayashi
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Shoichi Hazama
- Department of Translational Research and Developmental Therapeutics Against Cancer, Yamaguchi University School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Hidetoshi Eguchi
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Hiroaki Nagano
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
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15
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Yamada K, Hazama S, Suzuki N, Xu M, Nakagami Y, Fujiwara N, Tsunedomi R, Yoshida S, Tomochika S, Matsukuma S, Matsui H, Tokumitsu Y, Kanekiyo S, Shindo Y, Watanabe Y, Iida M, Takeda S, Ioka T, Ueno T, Ogihara H, Hamamoto Y, Hoshii Y, Kawano H, Fujita T, Kawakami Y, Nagano H. Siglec-7 is a predictive biomarker for the efficacy of cancer vaccination against metastatic colorectal cancer. Oncol Lett 2020; 21:10. [PMID: 33240416 PMCID: PMC7681234 DOI: 10.3892/ol.2020.12271] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/29/2020] [Indexed: 12/22/2022] Open
Abstract
Cancer immunotherapy, including vaccination, is considered a major scientific and medical breakthrough. However, cancer immunotherapy does not result in durable objective responses against colorectal cancer (CRC). To improve the efficacy of immunotherapy, the present study investigated several biomarkers for selecting patients who were expected to respond well to immunotherapy. Firstly, a comprehensive proteomic analysis was performed using tumor tissue lysates from patients enrolled in a phase II study, in which five human leukocyte antigen (HLA)-A*24:02-restricted peptides were administered. Sialic acid-binding immunoglobulin type lectin (Siglec)-7 was identified as a potential predictive biomarker. Subsequently, this biomarker was validated using western blot analysis, and immunofluorescence using tissue samples from the patients enrolled in the phase II study. The expression levels of Siglec-7 detected by immunofluorescence were quantified and their association with overall survival (OS) in patients treated with the peptide vaccine was examined. Furthermore, considering the important role of tumor-infiltrating lymphocytes (TILs) for CRC prognosis, the densities of CD3+, CD4+, CD8+ and forkhead box P3 (FOXP3)+ T cells in CRC tissues were examined and compared with Siglec-7 expression. The mean expression levels of Siglec-7 were significantly higher in patients with poor prognosis, with an OS of ≤2 years, as shown in comprehensive proteomic analysis (P=0.016) and western blot analysis (P=0.025). Immunofluorescence analysis demonstrated that Siglec-7 was expressed in intratumoral macrophages. The OS in patients with high Siglec-7 expression was significantly shorter than in that in patients with low Siglec-7 expression (P=0.017) in the HLA-A*24:02-matched patients. However, this difference was not observed in the HLA-unmatched patients. There was no significant difference in OS between patients according to the numbers of TILs, nor significant correlation between TILs and Siglec-7 expression. In conclusion, Siglec-7 expression in macrophages in tumor tissue may be a novel predictive biomarker for the efficacy of immunotherapy against metastatic CRC.
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Affiliation(s)
- Kensuke Yamada
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Shoichi Hazama
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan.,Department of Translational Research and Developmental Therapeutics Against Cancer, Yamaguchi University School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Nobuaki Suzuki
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Ming Xu
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Yuki Nakagami
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan.,Department of Translational Research and Developmental Therapeutics Against Cancer, Yamaguchi University School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Nobuyuki Fujiwara
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Ryouichi Tsunedomi
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Shin Yoshida
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Shinobu Tomochika
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Satoshi Matsukuma
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Hiroto Matsui
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Yukio Tokumitsu
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Shinsuke Kanekiyo
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Yoshitaro Shindo
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Yusaku Watanabe
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Michihisa Iida
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Shigeru Takeda
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Tatsuya Ioka
- Oncology Center, Yamaguchi University Hospital, Ube, Yamaguchi 755-8505, Japan
| | - Tomio Ueno
- Department of Gastroenterological Surgery, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
| | - Hiroyuki Ogihara
- Division of Electrical, Electronic and Information Engineering, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan
| | - Yoshihiko Hamamoto
- Division of Electrical, Electronic and Information Engineering, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan
| | - Yoshinobu Hoshii
- Department of Diagnostic Pathology, Yamaguchi University Hospital, Ube, Yamaguchi 755-8505, Japan
| | - Hiroo Kawano
- Department of Basic Laboratory Sciences, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Tomonobu Fujita
- Division of Cellular Signaling, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Yutaka Kawakami
- Division of Cellular Signaling, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Hiroaki Nagano
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
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16
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Labuzan SA, Lynch SA, Cooper LM, Waddell DS. Inhibition of protein phosphatase methylesterase 1 dysregulates MAP kinase signaling and attenuates muscle cell differentiation. Gene 2020; 739:144515. [DOI: 10.1016/j.gene.2020.144515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 02/07/2023]
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17
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Du B, Liao H, Zhang S. Expression Pattern and Prognostic Utility of PME-1 in Patients with Hepatocellular Carcinoma. Cancer Manag Res 2020; 12:2937-2945. [PMID: 32431540 PMCID: PMC7197939 DOI: 10.2147/cmar.s252873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 04/02/2020] [Indexed: 12/24/2022] Open
Abstract
Purpose Hepatocellular carcinoma (HCC) remains one of the most common malignancies. While there is lack of markers capable of predicting which patients are at risk of aggressive course of the disease. Although a few protein phosphatase methyl-esterase-1 (PME-1) tumor-promoting mechanisms have been reported, the role of PME-1 in cancer including HCC occurrence and progression remains to be elucidated. The aim of this study was to explore the expression pattern and relationship between PME-1 with the pathological parameters in patients with HCC. Methods PME-1 expression was assessed from HCC tissue chips via immunohistochemistry. Chi-square test was used to identify the association between PME-1 staining and clinicopathological variables of HCC patients. Kaplan–Meier analysis and Cox regression analysis were performed to draw survival curves and verify the independent prognostic factors of HCC patients, respectively. Results We found that PME-1 expression was significantly higher in HCC tumor tissues compared with non-tumor tissues (P < 0.001). Furthermore, high expression level of PME-1 was significantly associated with differentiation (P = 0.047), tumor number (P = 0.001), intrahepatic or extrahepatic metastasis (P = 0.018), and recurrence (P = 0.001). Kaplan–Meier analysis revealed that high expression level of PME-1 was associated with shorter survival (P < 0.001). Univariate analysis with Log-rank test revealed that PME-1 expression status was significantly correlated with overall survival (P < 0.001). Furthermore, multivariate models with Cox proportional hazards analysis showed that high expression of PME-1 was a statistically independent predictive factor of poor prognosis in HCC patients (hazard ratio, 3.429; 95% confidence interval, 1.369–8.589; P = 0.009). Conclusion In conclusion, these findings indicated that PME-1 expression was associated with aggressive pathological features and worse oncological outcomes, suggesting its potential therapeutic value for patients with HCC.
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Affiliation(s)
- Baoying Du
- Department of Hepatopancreatobiliary Surgery, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Hongfeng Liao
- Department of Pathology, Zhongshan Hospital of Xiamen University, Xiamen, People's Republic of China
| | - Sheng Zhang
- Department of Pathology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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18
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PP2A Functions during Mitosis and Cytokinesis in Yeasts. Int J Mol Sci 2019; 21:ijms21010264. [PMID: 31906018 PMCID: PMC6981662 DOI: 10.3390/ijms21010264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 12/13/2022] Open
Abstract
Protein phosphorylation is a common mechanism for the regulation of cell cycle progression. The opposing functions of cell cycle kinases and phosphatases are crucial for accurate chromosome segregation and exit from mitosis. Protein phosphatases 2A are heterotrimeric complexes that play essential roles in cell growth, proliferation, and regulation of the cell cycle. Here, we review the function of the protein phosphatase 2A family as the counteracting force for the mitotic kinases. We focus on recent findings in the regulation of mitotic exit and cytokinesis by PP2A phosphatases in S. cerevisiae and other fungal species.
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19
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Nader CP, Cidem A, Verrills NM, Ammit AJ. Protein phosphatase 2A (PP2A): a key phosphatase in the progression of chronic obstructive pulmonary disease (COPD) to lung cancer. Respir Res 2019; 20:222. [PMID: 31623614 PMCID: PMC6798356 DOI: 10.1186/s12931-019-1192-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 09/20/2019] [Indexed: 02/06/2023] Open
Abstract
Lung cancer (LC) has the highest relative risk of development as a comorbidity of chronic obstructive pulmonary disease (COPD). The molecular mechanisms that mediate chronic inflammation and lung function impairment in COPD have been identified in LC. This suggests the two diseases are more linked than once thought. Emerging data in relation to a key phosphatase, protein phosphatase 2A (PP2A), and its regulatory role in inflammatory and tumour suppression in both disease settings suggests that it may be critical in the progression of COPD to LC. In this review, we uncover the importance of the functional and active PP2A holoenzyme in the context of both diseases. We describe PP2A inactivation via direct and indirect means and explore the actions of two key PP2A endogenous inhibitors, cancerous inhibitor of PP2A (CIP2A) and inhibitor 2 of PP2A (SET), and the role they play in COPD and LC. We explain how dysregulation of PP2A in COPD creates a favourable inflammatory micro-environment and promotes the initiation and progression of tumour pathogenesis. Finally, we highlight PP2A as a druggable target in the treatment of COPD and LC and demonstrate the potential of PP2A re-activation as a strategy to halt COPD disease progression to LC. Although further studies are required to elucidate if PP2A activity in COPD is a causal link for LC progression, studies focused on the potential of PP2A reactivating agents to reduce the risk of LC formation in COPD patients will be pivotal in improving clinical outcomes for both COPD and LC patients in the future.
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Affiliation(s)
- Cassandra P Nader
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Aylin Cidem
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, 2308, Australia
- Priority Research Centre for Cancer Research, Innovation & Translation, Faculty of Health & Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW, 2305, Australia
| | - Alaina J Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.
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Remmerie M, Janssens V. PP2A: A Promising Biomarker and Therapeutic Target in Endometrial Cancer. Front Oncol 2019; 9:462. [PMID: 31214504 PMCID: PMC6558005 DOI: 10.3389/fonc.2019.00462] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 05/14/2019] [Indexed: 12/14/2022] Open
Abstract
Over the last decade, the use of targeted therapies has immensely increased in the treatment of cancer. However, treatment for endometrial carcinomas (ECs) has lagged behind, although potential molecular markers have been identified. This is particularly problematic for the type II ECs, since these aggressive tumors are usually not responsive toward the current standard therapies. Therefore, type II ECs are responsible for most EC-related deaths, indicating the need for new treatment options. Interestingly, molecular analyses of type II ECs have uncovered frequent genetic alterations (up to 40%) in PPP2R1A, encoding the Aα subunit of the tumor suppressive heterotrimeric protein phosphatase type 2A (PP2A). PPP2R1A mutations were also reported in type I ECs and other common gynecologic cancers, albeit at much lower frequencies (0-7%). Nevertheless, PP2A inactivation in the latter cancer types is common via other mechanisms, in particular by increased expression of Cancerous Inhibitor of PP2A (CIP2A) and PP2A Methylesterase-1 (PME-1) proteins. In this review, we discuss the therapeutic potential of direct and indirect PP2A targeting compounds, possibly in combination with other anti-cancer drugs, in EC. Furthermore, we investigate the potential of the PP2A status as a predictive and/or prognostic marker for type I and II ECs.
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Affiliation(s)
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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