1
|
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.
Collapse
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.
| |
Collapse
|
2
|
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.
Collapse
|
3
|
O’Connor CM, Taylor SE, Miller KM, Hurst L, Haanen TJ, Suhan TK, Zawacki KP, Noto FK, Trako J, Mohan A, Sangodkar J, Zamarin D, DiFeo A, Narla G. Targeting Ribonucleotide Reductase Induces Synthetic Lethality in PP2A-Deficient Uterine Serous Carcinoma. Cancer Res 2022; 82:721-733. [PMID: 34921012 PMCID: PMC8857033 DOI: 10.1158/0008-5472.can-21-1987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/14/2021] [Accepted: 11/30/2021] [Indexed: 11/16/2022]
Abstract
Uterine serous carcinoma (USC) is a highly aggressive endometrial cancer subtype with limited therapeutic options and a lack of targeted therapies. While mutations to PPP2R1A, which encodes the predominant protein phosphatase 2A (PP2A) scaffolding protein Aα, occur in 30% to 40% of USC cases, the clinical actionability of these mutations has not been studied. Using a high-throughput screening approach, we showed that mutations in Aα results in synthetic lethality following treatment with inhibitors of ribonucleotide reductase (RNR). In vivo, multiple models of Aα mutant uterine serous tumors were sensitive to clofarabine, an RNR inhibitor (RNRi). Aα-mutant cells displayed impaired checkpoint signaling upon RNRi treatment and subsequently accumulated more DNA damage than wild-type (WT) cells. Consistently, inhibition of PP2A activity using LB-100, a catalytic inhibitor, sensitized WT USC cells to RNRi. Analysis of The Cancer Genome Atlas data indicated that inactivation of PP2A, through loss of PP2A subunit expression, was prevalent in USC, with 88% of patients with USC harboring loss of at least one PP2A gene. In contrast, loss of PP2A subunit expression was rare in uterine endometrioid carcinomas. While RNRi are not routinely used for uterine cancers, a retrospective analysis of patients treated with gemcitabine as a second- or later-line therapy revealed a trend for improved outcomes in patients with USC treated with RNRi gemcitabine compared with patients with endometrioid histology. Overall, our data provide experimental evidence to support the use of ribonucleotide reductase inhibitors for the treatment of USC. SIGNIFICANCE A drug repurposing screen identifies synthetic lethal interactions in PP2A-deficient uterine serous carcinoma, providing potential therapeutic avenues for treating this deadly endometrial cancer.
Collapse
Affiliation(s)
- Caitlin M. O’Connor
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
| | - Sarah E. Taylor
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Kathryn M. Miller
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York City, New York
| | - Lauren Hurst
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Terrance J. Haanen
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
- Department of Cancer Biology, The University of Michigan, Ann Arbor, Michigan
| | - Tahra K. Suhan
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Kaitlin P. Zawacki
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | | | - Jonida Trako
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Arathi Mohan
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Jaya Sangodkar
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
| | - Dmitriy Zamarin
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York City, New York
| | - Analisa DiFeo
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
- Department of Pathology, The University of Michigan, Ann Arbor, Michigan
- Department of Obstetrics and Gynecology, The University of Michigan, Ann Arbor, Michigan
| | - Goutham Narla
- Department of Internal Medicine: Division of Genetic Medicine, The University of Michigan, Ann Arbor, Michigan
- Rogel Cancer Center, The University of Michigan, Ann Arbor, Michigan
| |
Collapse
|
4
|
Cleavage and Polyadenylation Specificity Factor 6 Is Required for Efficient HIV-1 Latency Reversal. mBio 2021; 12:e0109821. [PMID: 34154414 PMCID: PMC8262898 DOI: 10.1128/mbio.01098-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The HIV-1 latent reservoir is the major barrier to an HIV cure. Due to low levels or lack of transcriptional activity, HIV-1 latent proviruses in vivo are not easily detectable and cannot be targeted by either natural immune mechanisms or molecular therapies based on protein expression. To target the latent reservoir, further understanding of HIV-1 proviral transcription is required. In this study, we demonstrate a novel role for cleavage and polyadenylation specificity factor 6 (CPSF6) in HIV-1 transcription. We show that knockout of CPSF6 hinders reactivation of latent HIV-1 proviruses by PMA in primary CD4+ cells. CPSF6 knockout reduced HIV-1 transcription, concomitant with a drastic reduction in the phosphorylation levels of Pol II and CDK9. Knockout of CPSF6 led to abnormal stabilization of protein phosphatase 2A (PP2A) subunit A, which then acted to dephosphorylate CDK9, downmodulating CDK9's ability to phosphorylate the Pol II carboxy-terminal domain. In agreement with this mechanism, incubation with the PP2A inhibitor, LB100, restored HIV-1 transcription in the CPSF6 knockout cells. Destabilization of PP2A subunit A occurs in the ubiquitin proteasome pathway, wherein CPSF6 acts as a substrate adaptor for the ITCH ubiquitin ligase. Our observations reveal a novel role of CPSF6 in HIV-1 transcription, which appears to be independent of its known roles in cleavage and polyadenylation and the targeting of preintegration complexes to the chromatin for viral DNA integration. IMPORTANCE CPSF6 is a cellular factor that regulates cleavage and polyadenylation of mRNAs and participates in HIV-1 infection by facilitating targeting of preintegration complexes to the chromatin. Our observations reveal a second role of CPSF6 in the HIV-1 life cycle that involves regulation of viral transcription through controlling the stability of protein phosphatase 2A, which in turn regulates the phosphorylation/dephosphorylation status of critical residues in CDK9 and Pol II.
Collapse
|
5
|
Chen L, Guo P, Li W, Fang F, Zhu W, Fan J, Wang F, Gao Y, Zhao Q, Wang Q, Xiao Y, Xing X, Li D, Shi T, Yu D, Aschner M, Zhang L, Chen W. Perturbation of Specific Signaling Pathways Is Involved in Initiation of Mouse Liver Fibrosis. Hepatology 2021; 73:1551-1569. [PMID: 32654205 DOI: 10.1002/hep.31457] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/09/2020] [Accepted: 06/11/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND AIMS To identify the regulatory role of protein phosphatase 2A (PP2A) in the development of liver disease, we generated a mouse model with hepatocyte-specific deletion of Ppp2r1a gene (encoding PP2A Aα subunit). APPROACH AND RESULTS Homozygote (HO) mice and matched wild-type littermates were investigated at 3, 6, 9, 12, 15, and 18 months of age. Pathological examination showed that PP2A Aα deficiency in hepatocytes resulted in progressive liver fibrosis phenotype from 9 months of age. No hepatocyte death was observed in HO mice. However, perturbation of pathways including epidermal growth factor receptor 1 (EGFR1), amino acid metabolism, and translation factors as well as leptin and adiponectin led to pronounced hepatic fibrosis. In vitro studies demonstrated the involvement of specific B subunit complexes in the regulation of EGFR1 signaling pathway and cross talk between defected hepatocytes and stimulation of interstitial hyperplasia. It is noteworthy that HO mice failed to develop hepatocellular carcinoma for as long as 22 months of age. We further demonstrate that PP2A Aβ-containing holoenzymes played a critical role in preventing hepatocyte apoptosis and antagonizing tumorigenesis through specific pathways on Aα loss. Furthermore, PP2A Aα and Aβ were functionally distinct, and the Aβ isoform failed to substitute for Aα in the development of inflammation and liver fibrosis. CONCLUSIONS These observations identify pathways that contribute to the pathogenesis of liver fibrosis and provide putative therapeutic targets for its treatment.
Collapse
Affiliation(s)
- Liping Chen
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Ping Guo
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Wenxue Li
- Department of Toxicology, Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Fei Fang
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian, China
| | - Wei Zhu
- Department of Toxicology, Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Junling Fan
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Fangping Wang
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Yuanyuan Gao
- The Center for Bioinformatics and Computational Biology, Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Qun Zhao
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian, China
| | - Qing Wang
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Yongmei Xiao
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Xiumei Xing
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Daochuan Li
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Tieliu Shi
- The Center for Bioinformatics and Computational Biology, Shanghai Key Laboratory of Regulatory Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Dianke Yu
- School of Public Health, Qingdao University, Qingdao, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY
| | - Lihua Zhang
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, National Chromatographic Research and Analysis Center, Dalian, China
| | - Wen Chen
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|
6
|
O'Connor CM, Leonard D, Wiredja D, Avelar RA, Wang Z, Schlatzer D, Bryson B, Tokala E, Taylor SE, Upadhyay A, Sangodkar J, Gingras AC, Westermarck J, Xu W, DiFeo A, Brautigan DL, Haider S, Jackson M, Narla G. Inactivation of PP2A by a recurrent mutation drives resistance to MEK inhibitors. Oncogene 2020; 39:703-717. [PMID: 31541192 PMCID: PMC6980487 DOI: 10.1038/s41388-019-1012-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/26/2019] [Accepted: 08/09/2019] [Indexed: 12/27/2022]
Abstract
The serine/threonine Protein Phosphatase 2A (PP2A) functions as a tumor suppressor by negatively regulating multiple oncogenic signaling pathways. The canonical PP2A holoenzyme comprises a scaffolding subunit (PP2A Aα/β), which serves as the platform for binding of both the catalytic C subunit and one regulatory B subunit. Somatic heterozygous missense mutations in PPP2R1A, the gene encoding the PP2A Aα scaffolding subunit, have been identified across multiple cancer types, but the effects of the most commonly mutated residue, Arg-183, on PP2A function have yet to be fully elucidated. In this study, we used a series of cellular and in vivo models and discovered that the most frequent Aα R183W mutation formed alternative holoenzymes by binding of different PP2A regulatory subunits compared with wild-type Aα, suggesting a rededication of PP2A functions. Unlike wild-type Aα, which suppressed tumorigenesis, the R183W mutant failed to suppress tumor growth in vivo through activation of the MAPK pathway in RAS-mutant transformed cells. Furthermore, cells expressing R183W were less sensitive to MEK inhibitors. Taken together, our results demonstrate that the R183W mutation in PP2A Aα scaffold abrogates the tumor suppressive actions of PP2A, thereby potentiating oncogenic signaling and reducing drug sensitivity of RAS-mutant cells.
Collapse
Affiliation(s)
- Caitlin M O'Connor
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Daniel Leonard
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Danica Wiredja
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH, USA
| | - Rita A Avelar
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Zhizhi Wang
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Daniela Schlatzer
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH, USA
| | - Benjamin Bryson
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Eesha Tokala
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah E Taylor
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Aditya Upadhyay
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Jaya Sangodkar
- Department of Internal Medicine: Genetic Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Jukka Westermarck
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Wenqing Xu
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Analisa DiFeo
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA
| | - David L Brautigan
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Shozeb Haider
- Department of Pharmaceutical and Biological Chemistry, University College London, London, UK
| | - Mark Jackson
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - Goutham Narla
- Department of Internal Medicine: Genetic Medicine, University of Michigan, Ann Arbor, MI, USA.
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA.
| |
Collapse
|