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Kokot T, Zimmermann JP, Schwäble AN, Reimann L, Herr AL, Höfflin N, Köhn M, Warscheid B. Protein phosphatase-1 regulates the binding of filamin C to FILIP1 in cultured skeletal muscle cells under mechanical stress. Sci Rep 2024; 14:27348. [PMID: 39521905 PMCID: PMC11550807 DOI: 10.1038/s41598-024-78953-8] [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: 07/22/2024] [Accepted: 11/05/2024] [Indexed: 11/16/2024] Open
Abstract
The actin-binding protein filamin c (FLNc) is a key mediator in the response of skeletal muscle cells to mechanical stress. In addition to its function as a structural scaffold, FLNc acts as a signaling adaptor which is phosphorylated at S2234 in its mechanosensitive domain 20 (d20) through AKT. Here, we discovered a strong dephosphorylation of FLNc-pS2234 in cultured skeletal myotubes under acute mechanical stress, despite high AKT activity. We found that all three protein phosphatase 1 (PP1) isoforms are part of the FLNc d18-21 interactome. Enzymatic assays demonstrate that PP1 efficiently dephosphorylates FLNc-pS2234 and in vitro and in cells upon PP1 activation using specific modulators. FLNc-pS2234 dephosphorylation promotes the interaction with FILIP1, a mediator for filamin degradation. Altogether, we present a model in which dephosphorylation of FLNc d20 by the dominant action of PP1c prevails over AKT activity to promote the binding of the filamin degradation-inducing factor FILIP1 during acute mechanical stress.
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Affiliation(s)
- Thomas Kokot
- Integrative Signaling Research, Institute of Biology III, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Johannes P Zimmermann
- Biochemistry II, Theodor-Boveri-Institut, Biozentrum, Faculty of Chemistry and Pharmacy, University of Würzburg, Würzburg, Germany
| | - Anja N Schwäble
- Biochemistry - Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany
- Current address: Celonic AG, Basel, Switzerland
| | - Lena Reimann
- Biochemistry - Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany
- Current address: Celonic AG, Basel, Switzerland
| | - Anna L Herr
- Biochemistry - Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany
- Current address: Sartorius CellGenix GmbH, Freiburg, Germany
| | - Nico Höfflin
- Integrative Signaling Research, Institute of Biology III, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Maja Köhn
- Integrative Signaling Research, Institute of Biology III, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Bettina Warscheid
- Biochemistry II, Theodor-Boveri-Institut, Biozentrum, Faculty of Chemistry and Pharmacy, University of Würzburg, Würzburg, Germany.
- Biochemistry - Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany.
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2
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Matos B, Gomes AAS, Bernardino R, Alves MG, Howl J, Jerónimo C, Fardilha M. CAVPENET Peptide Inhibits Prostate Cancer Cells Proliferation and Migration through PP1γ-Dependent Inhibition of AKT Signaling. Pharmaceutics 2024; 16:1199. [PMID: 39339236 PMCID: PMC11434739 DOI: 10.3390/pharmaceutics16091199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Revised: 09/03/2024] [Accepted: 09/08/2024] [Indexed: 09/30/2024] Open
Abstract
Protein phosphatase 1 (PP1) complexes have emerged as promising targets for anticancer therapies. The ability of peptides to mimic PP1-docking motifs, and so modulate interactions with regulatory factors, has enabled the creation of highly selective modulators of PP1-dependent cellular processes that promote tumor growth. The major objective of this study was to develop a novel bioactive cell-penetrating peptide (bioportide), which, by mimicking the PP1-binding motif of caveolin-1 (CAV1), would regulate PP1 activity, to hinder prostate cancer (PCa) progression. The designed bioportide, herein designated CAVPENET, and a scrambled homologue, were synthesized using microwave-assisted solid-phase methodologies and evaluated using PCa cell lines. Our findings indicate that CAVPENET successfully entered PCa cells to influence both viability and migration. This tumor suppressor activity of CAVPENET was attributed to inhibition of AKT signaling, a consequence of increased PP1γ activity. This led to the suppression of glycolytic metabolism and alteration in lipid metabolism, collectively representing the primary mechanism responsible for the anticancer properties of CAVPENET. Our results underscore the potential of the designed peptide as a novel therapy for PCa patients, setting the stage for further testing in more advanced models to fully realize its therapeutic promise.
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Affiliation(s)
- Bárbara Matos
- Laboratory of Signal Transduction, Department of Medical Sciences, iBiMED-Institute of Biomedicine, University of Aveiro, 3810-193 Aveiro, Portugal
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO Porto), Porto Comprehensive Cancer Center Raquel Seruca (Porto.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal
| | - Antoniel A S Gomes
- Department of Biophysics & Pharmacology, Institute of Biosciences of Botucatu, São Paulo State University, Botucatu 18610-034, SP, Brazil
| | - Raquel Bernardino
- Unit for Multidisciplinary Research in Biomedicine (UMIB), School of Medicine and Biomedical Sciences (ICBAS), University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), 4050-600 Porto, Portugal
| | - Marco G Alves
- Department of Medical Sciences, iBiMED-Institute of Biomedicine, University of Aveiro, 3810-193 Aveiro, Portugal
| | - John Howl
- Faculty of Health, Education and Life Sciences, Birmingham City University, Edgbaston, Birmingham B15 3TN, UK
| | - Carmen Jerónimo
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO Porto), Porto Comprehensive Cancer Center Raquel Seruca (Porto.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal
- Department of Pathology and Molecular Immunology, ICBAS-School of Medicine and Biomedical Sciences, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Margarida Fardilha
- Laboratory of Signal Transduction, Department of Medical Sciences, iBiMED-Institute of Biomedicine, University of Aveiro, 3810-193 Aveiro, Portugal
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3
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Wißfeld J, Hering M, Ten Bosch N, Cui G. The immunosuppressive drug cyclosporin A has an immunostimulatory function in CD8 + T cells. Eur J Immunol 2024; 54:e2350825. [PMID: 38650034 DOI: 10.1002/eji.202350825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 04/03/2024] [Accepted: 04/05/2024] [Indexed: 04/25/2024]
Abstract
Cyclosporin A is a well-established immunosuppressive drug used to treat or prevent graft-versus-host disease, the rejection of organ transplants, autoimmune disorders, and leukemia. It exerts its immunosuppressive effects by inhibiting calcineurin-mediated dephosphorylation of the nuclear factor of activated T cells (NFAT), thus preventing its nuclear entry and suppressing T cell activation. Here we report an unexpected immunostimulatory effect of cyclosporin A in activating the mammalian target of rapamycin complex 1 (mTORC1), a crucial metabolic hub required for T cell activation. Through screening a panel of tool compounds known to regulate mTORC1 activation, we found that cyclosporin A activated mTORC1 in CD8+ T cells in a 3-phosphoinositide-dependent protein kinase 1 (PDK1) and protein kinase B (PKB/AKT)-dependent manner. Mechanistically, cyclosporin A inhibited the calcineurin-mediated AKT dephosphorylation, thereby stabilizing mTORC1 signaling. Cyclosporin A synergized with mTORC1 pathway inhibitors, leading to potent suppression of proliferation and cytokine production in CD8+ T cells and an increase in the killing of acute T cell leukemia cells. Consequently, relying solely on CsA is insufficient to achieve optimal therapeutic outcomes. It is necessary to simultaneously target both the calcineurin-NFAT pathway and the mTORC1 pathway to maximize therapeutic efficacy.
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Affiliation(s)
- Jannis Wißfeld
- Helmholtz Institute for Translational Oncology (HI-TRON) Mainz, Mainz, Germany
- T Cell Metabolism Group (D192), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marvin Hering
- Helmholtz Institute for Translational Oncology (HI-TRON) Mainz, Mainz, Germany
- T Cell Metabolism Group (D192), German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
- Skin Cancer Unit, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim (UMM), Mannheim, Germany
| | - Nora Ten Bosch
- Helmholtz Institute for Translational Oncology (HI-TRON) Mainz, Mainz, Germany
- T Cell Metabolism Group (D192), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Guoliang Cui
- Helmholtz Institute for Translational Oncology (HI-TRON) Mainz, Mainz, Germany
- T Cell Metabolism Group (D192), German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
- Key Laboratory of Immune Response and Immunotherapy, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
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4
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Nie Y, Chu C, Qin Q, Shen H, Wen L, Tang Y, Qu M. Lipid metabolism and oxidative stress in patients with Alzheimer's disease and amnestic mild cognitive impairment. Brain Pathol 2024; 34:e13202. [PMID: 37619589 PMCID: PMC10711261 DOI: 10.1111/bpa.13202] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 07/26/2023] [Indexed: 08/26/2023] Open
Abstract
Lipid metabolism and oxidative stress are key mechanisms in Alzheimer's disease (AD). The link between plasma lipid metabolites and oxidative stress in AD patients is poorly understood. This study was to identify markers that distinguish AD and amnestic mild cognitive impairment (aMCI) from NC, and to reveal potential links between lipid metabolites and oxidative stress. We performed non-targeted lipid metabolism analysis of plasma from patients with AD, aMCI, and NC using LC-MS/MS. The plasma malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) levels were assessed. We found significant differences in lipid metabolism between patients with AD and aMCI compared to those in NC. AD severity is associated with lipid metabolites, especially TG (18:0_16:0_18:0) + NH4, TG (18:0_16:0_16:0) + NH4, LPC(16:1e)-CH3, and PE (20:0_20:4)-H. SPH (d16:0) + H, SPH (d18:1) + H, and SPH (d18:0) + H were high-performance markers to distinguish AD and aMCI from NC. The AUC of three SPHs combined to predict AD was 0.990, with specificity and sensitivity as 0.949 and 1, respectively; the AUC of three SPHs combined to predict aMCI was 0.934, with specificity and sensitivity as 0.900, 0.981, respectively. Plasma MDA concentrations were higher in the AD group than in the NC group (p = 0.003), whereas plasma SOD levels were lower in the AD (p < 0.001) and aMCI (p = 0.045) groups than in NC, and GSH-Px activity were higher in the AD group than in the aMCI group (p = 0.007). In addition, lipid metabolites and oxidative stress are widely associated. In conclusion, this study distinguished serum lipid metabolism in AD, aMCI, and NC subjects, highlighting that the three SPHs can distinguish AD and aMCI from NC. Additionally, AD patients showed elevated oxidative stress, and there are complex interactions between lipid metabolites and oxidative stress.
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Affiliation(s)
- Yuting Nie
- Department of NeurologyXuanwu Hospital, Capital Medical UniversityBeijingChina
| | - Changbiao Chu
- Department of NeurologyXuanwu Hospital, Capital Medical UniversityBeijingChina
| | - Qi Qin
- Department of NeurologyXuanwu Hospital, Capital Medical UniversityBeijingChina
| | - Huixin Shen
- Department of NeurologyXuanwu Hospital, Capital Medical UniversityBeijingChina
| | - Lulu Wen
- Department of NeurologyXuanwu Hospital, Capital Medical UniversityBeijingChina
| | - Yi Tang
- Department of NeurologyXuanwu Hospital, Capital Medical UniversityBeijingChina
| | - Miao Qu
- Department of NeurologyXuanwu Hospital, Capital Medical UniversityBeijingChina
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5
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Wu C, Zhang W, Luo Y, Cheng C, Wang X, Jiang Y, Li S, Luo L, Yang Y. Zebrafish ppp1r21 mutant as a model for the study of primary biliary cholangitis. J Genet Genomics 2023; 50:1004-1013. [PMID: 37271428 DOI: 10.1016/j.jgg.2023.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 05/05/2023] [Accepted: 05/22/2023] [Indexed: 06/06/2023]
Abstract
Primary biliary cholangitis (PBC) is an autoimmune cholestatic liver disease that progresses to fibrosis and cirrhosis, resulting from the gradual destruction of intrahepatic bile ducts. Exploring genetic variants associated with PBC is essential to understand the pathogenesis of PBC. Here we identify a zebrafish balloon dog (blg) mutant with intrahepatic bile duct branching defects, exhibiting several key pathological PBC-like features, including immunodominant autoantigen PDC-E2 production, cholangiocyte apoptosis, immune cell infiltration, inflammatory activation, and liver fibrosis. blg encodes the protein phosphatase 1 regulatory subunit 21 (Ppp1r21), which is enriched in the liver and its peripheral tissues and plays a vital role in the early intrahepatic bile duct formation stage. Further studies show an excessive activation of the PI3K/AKT/mTOR pathway in the hepatic tissues in the mutant, while treatment with the pathway inhibitor LY294002 and rapamycin partially rescues intrahepatic bile duct branching defects and alleviates the PBC-like symptoms. These findings implicate the potential role of the Ppp1r21-mediated PI3K/AKT/mTOR pathway in the pathophysiology of PBC.
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Affiliation(s)
- Chaoying Wu
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Wenfeng Zhang
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Yiyu Luo
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Chaoqing Cheng
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Xinjuan Wang
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Yan Jiang
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Shuang Li
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Lingfei Luo
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Yun Yang
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China.
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Yadav Y, Sharma M, Dey CS. PP1γ regulates neuronal insulin signaling and aggravates insulin resistance leading to AD-like phenotypes. Cell Commun Signal 2023; 21:82. [PMID: 37085815 PMCID: PMC10120118 DOI: 10.1186/s12964-023-01071-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 02/08/2023] [Indexed: 04/23/2023] Open
Abstract
BACKGROUND PP1γ is one of the isoforms of catalytic subunit of a Ser/Thr phosphatase PP1. The role of PP1γ in cellular regulation is largely unknown. The present study investigated the role of PP1γ in regulating neuronal insulin signaling and insulin resistance in neuronal cells. PP1 was inhibited in mouse neuroblastoma cells (N2a) and human neuroblastoma cells (SH-SY5Y). The expression of PP1α and PP1γ was determined in insulin resistant N2a, SH-SY5Y cells and in high-fat-diet-fed-diabetic mice whole-brain-lysates. PP1α and PP1γ were silenced by siRNA in N2a and SH-SY5Y cells and effect was tested on AKT isoforms, AS160 and GSK3 isoforms using western immunoblot, GLUT4 translocation by confocal microscopy and glucose uptake by fluorescence-based assay. RESULTS Results showed that, in one hand PP1γ, and not PP1α, regulates neuronal insulin signaling and insulin resistance by regulating phosphorylation of AKT2 via AKT2-AS160-GLUT4 axis. On the other hand, PP1γ regulates phosphorylation of GSK3β via AKT2 while phosphorylation of GSK3α via MLK3. Imbalance in this regulation results into AD-like phenotype. CONCLUSION PP1γ acts as a linker, regulating two pathophysiological conditions, neuronal insulin resistance and AD. Video Abstract.
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Affiliation(s)
- Yamini Yadav
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Medha Sharma
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Chinmoy Sankar Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India.
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7
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Kim HG, Jeong SG, Kim JH, Cho JY. Phosphatase inhibition by sodium orthovanadate displays anti-inflammatory action by suppressing AKT-IKKβ signaling in RAW264.7 cells. Toxicol Rep 2022; 9:1883-1893. [PMID: 36518371 PMCID: PMC9742970 DOI: 10.1016/j.toxrep.2022.09.012] [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: 07/25/2022] [Revised: 09/08/2022] [Accepted: 09/29/2022] [Indexed: 11/06/2022] Open
Abstract
Sodium orthovanadate (Na3VO4) is an inhibitor of phosphatases that acts as a phosphate analog and is being developed as an anti-diabetes drug. Phosphatases play important roles in inflammatory signal pathways by modulating the removal of phosphate moieties of key signaling proteins. However, the role of protein phosphatases on the inflammatory response has not been fully established. In this study, we investigated how phosphatases can control the inflammatory response using Na3VO4 in LPS-stimulated RAW264.7 cells and explored the molecular mechanisms by NO assay, mRNA analysis, immunoblotting analysis, kinase assay, luciferase reporter gene assay, and mutation strategy. Na3VO4 decreased the release of nitric oxide (NO) and suppressed the expression of pro-inflammatory genes at the transcriptional level, without cytotoxicity. The translocation of nuclear factor (NF)-κB subunits into the nucleus and the level of p-IκBα were reduced by Na3VO4, as was IKKβ activity. Na3VO4 inhibited NF-κB-Luc activity under AKT1/2 and IKKβ overexpression. However, the inhibitory effect of Na3VO4 against NF-κB-Luc was not observed in the group overexpressing both AKT2 and IKKβ-M10, a mutant in which the 10 serine residues in the autophosphorylated region of the C-terminal were replaced with alanine. Na3VO4 directly decreased the activity of protein phosphatase 1α (PP1α) and protein phosphatase 2 A (PP2A) by 95%. Phosphatase inhibition by Na3VO4 also selectively suppressed AKT-IKKβ signaling by directly blocking the phosphatase activity of PP1 and PP2A, consequently down-regulating NF-κB and inflammatory gene expression. Therefore, these results suggest that vanadium compounds including Na3VO4 can be developed as anti-inflammatory drugs.
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Affiliation(s)
| | | | - Ji Hye Kim
- Department of Integrative Biotechnology and Biomedical Institute for Convergence at SKKU, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jae Youl Cho
- Department of Integrative Biotechnology and Biomedical Institute for Convergence at SKKU, Sungkyunkwan University, Suwon 16419, Republic of Korea
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Matos B, Howl J, Jerónimo C, Fardilha M. Modulation of serine/threonine-protein phosphatase 1 (PP1) complexes: A promising approach in cancer treatment. Drug Discov Today 2021; 26:2680-2698. [PMID: 34390863 DOI: 10.1016/j.drudis.2021.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/23/2021] [Accepted: 08/05/2021] [Indexed: 01/21/2023]
Abstract
Cancer is the second leading cause of death worldwide. Despite the availability of numerous therapeutic options, tumor heterogeneity and chemoresistance have limited the success of these treatments, and the development of effective anticancer therapies remains a major focus in oncology research. The serine/threonine-protein phosphatase 1 (PP1) and its complexes have been recognized as potential drug targets. Research on the modulation of PP1 complexes is currently at an early stage, but has immense potential. Chemically diverse compounds have been developed to disrupt or stabilize different PP1 complexes in various cancer types, with the objective of inhibiting disease progression. Beneficial results obtained in vitro now require further pre-clinical and clinical validation. In conclusion, the modulation of PP1 complexes seems to be a promising, albeit challenging, therapeutic strategy for cancer.
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Affiliation(s)
- Bárbara Matos
- Laboratory of Signal Transduction, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal; Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Institute of Oncology of Porto (IPO Porto), 4200-072 Porto, Portugal
| | - John Howl
- Molecular Pharmacology Group, Research Institute in Healthcare Science, University of Wolverhampton, Wolverhampton WV1 1LY, UK
| | - Carmen Jerónimo
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Institute of Oncology of Porto (IPO Porto), 4200-072 Porto, Portugal; Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), 4050-513 Porto, Portugal
| | - Margarida Fardilha
- Laboratory of Signal Transduction, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal.
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Haapalainen AM, Daddali R, Hallman M, Rämet M. Human CPPED1 belongs to calcineurin-like metallophosphoesterase superfamily and dephosphorylates PI3K-AKT pathway component PAK4. J Cell Mol Med 2021; 25:6304-6317. [PMID: 34009729 PMCID: PMC8366450 DOI: 10.1111/jcmm.16607] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 04/20/2021] [Accepted: 04/26/2021] [Indexed: 12/20/2022] Open
Abstract
Protein kinases and phosphatases regulate cellular processes by reversible phosphorylation and dephosphorylation events. CPPED1 is a recently identified serine/threonine protein phosphatase that dephosphorylates AKT1 of the PI3K-AKT signalling pathway. We previously showed that CPPED1 levels are down-regulated in the human placenta during spontaneous term birth. In this study, based on sequence comparisons, we propose that CPPED1 is a member of the class III phosphodiesterase (PDE) subfamily within the calcineurin-like metallophosphoesterase (MPE) superfamily rather than a member of the phosphoprotein phosphatase (PPP) or metal-dependent protein phosphatase (PPM) protein families. We used a human proteome microarray to identify 36 proteins that putatively interact with CPPED1. Of these, GRB2, PAK4 and PIK3R2 are known to regulate the PI3K-AKT pathway. We further confirmed CPPED1 interactions with PAK4 and PIK3R2 by coimmunoprecipitation analyses. We characterized the effect of CPPED1 on phosphorylation of PAK4 and PIK3R2 in vitro by mass spectrometry. CPPED1 dephosphorylated specific serine residues in PAK4, while phosphorylation levels in PIK3R2 remained unchanged. Our findings indicate that CPPED1 may regulate PI3K-AKT pathway activity at multiple levels. Higher CPPED1 levels may inhibit PI3K-AKT pathway maintaining pregnancy. Consequences of decreased CPPED1 expression during labour remain to be elucidated.
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Affiliation(s)
- Antti M. Haapalainen
- PEDEGO Research Unit and Medical Research Center OuluUniversity of OuluOuluFinland
- Department of Children and AdolescentsOulu University HospitalOuluFinland
| | - Ravindra Daddali
- PEDEGO Research Unit and Medical Research Center OuluUniversity of OuluOuluFinland
- Department of Children and AdolescentsOulu University HospitalOuluFinland
| | - Mikko Hallman
- PEDEGO Research Unit and Medical Research Center OuluUniversity of OuluOuluFinland
- Department of Children and AdolescentsOulu University HospitalOuluFinland
| | - Mika Rämet
- PEDEGO Research Unit and Medical Research Center OuluUniversity of OuluOuluFinland
- Department of Children and AdolescentsOulu University HospitalOuluFinland
- Faculty of Medicine and Health TechnologyTampere UniversityTampereFinland
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Dong W, Rasid O, Chevalier C, Connor M, Eldridge MJG, Hamon MA. Streptococcus pneumoniae Infection Promotes Histone H3 Dephosphorylation by Modulating Host PP1 Phosphatase. Cell Rep 2021; 30:4016-4026.e4. [PMID: 32209465 DOI: 10.1016/j.celrep.2020.02.116] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/15/2020] [Accepted: 02/21/2020] [Indexed: 10/24/2022] Open
Abstract
Pathogenic bacteria can alter host gene expression through post-translational modifications of histones. We show that a natural colonizer, Streptococcus pneumoniae, induces specific histone modifications, including robust dephosphorylation of histone H3 on serine 10 (H3S10), during infection of respiratory epithelial cells. The bacterial pore-forming toxin pneumolysin (PLY), along with the pyruvate oxidase SpxB responsible for H2O2 production, play important roles in the induction of this modification. The combined effects of PLY and H2O2 trigger host signaling that culminates in H3S10 dephosphorylation, which is mediated by the host cell phosphatase PP1. Strikingly, S. pneumoniae infection induces dephosphorylation and subsequent activation of PP1 catalytic activity. Colonization of PP1 catalytically deficient cells results in impaired intracellular S. pneumoniae survival and infection. Interestingly, PP1 activation and H3S10 dephosphorylation are not restricted to S. pneumoniae and appear to be general epigenomic mechanisms favoring intracellular survival of pathogenic bacteria.
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Affiliation(s)
- Wenyang Dong
- G5 Chromatine et Infection, Institut Pasteur, Paris 75015, France; Université de Paris, Sorbonne Paris Cité, Paris, France
| | - Orhan Rasid
- G5 Chromatine et Infection, Institut Pasteur, Paris 75015, France
| | | | - Michael Connor
- G5 Chromatine et Infection, Institut Pasteur, Paris 75015, France
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Oda S, Hirabuki Y, Takeuchi T, Kagawa T, Yokoi T. Plasma miR-218a-5p as a biomarker for acute cholestatic liver injury in rats and investigation of its pathophysiological roles. J Appl Toxicol 2021; 41:1537-1552. [PMID: 33565098 DOI: 10.1002/jat.4144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/28/2020] [Accepted: 01/11/2021] [Indexed: 01/07/2023]
Abstract
MicroRNAs (miRNA) have received considerable attention as potential biomarkers for drug-induced liver injury. We recently reported that the plasma levels of miR-143-3p and miR-218a-5p increased in severe cholestasis in rats. This study aimed to investigate whether these miRNAs increase in a severity-dependent manner and to elucidate their pathophysiological roles in cholestasis. Male Sprague-Dawley rats were orally administered different doses of α-naphthylisothiocyanate or 4,4-methylenedianiline to induce acute cholestasis. They were also orally administered acetaminophen or thioacetamide to induce hepatocellular injury. We found that plasma miR-143-3p and miR-218a-5p levels increased in a dose-dependent manner in cholestatic rats but not in hepatocellular injury. Bioinformatic analysis provided putative target genes of hsa-miR-218-5p, rno-miR-218a-5p, and mmu-miR-218-5p, among which GNAI2, PPP1CB, and PPP2R5A were experimentally validated as their direct target genes in human cholangiocyte line MMNK-1. Proliferation of MMNK-1 cells was significantly suppressed after overexpression of miR-218-5p and transduction of siRNAs for GNAI2, PPP1CB, and PPP2R5A. In the cholestatic livers of rats, Ppp1cb and Ppp2r5a expression levels decreased, whereas Gnai2 expression levels increased compared with those in vehicle-treated rats, suggesting that Ppp1cb and Ppp2r5a may be under the control of miR-218a-5p in vivo. In conclusion, our data suggest that miR-218(a)-5p is involved in the suppression of cholangiocyte proliferation by inhibiting the expression of PPP1CB and PPP2R5A, thereby contributing to the pathogenesis of cholestasis; and miR-218a-5p leaks into the plasma probably from damaged cholangiocytes in a severity-dependent manner in rats. Therefore, miR-218a-5p overexpression could be one of the underlying mechanisms of acute cholestatic liver injury in rats.
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Affiliation(s)
- Shingo Oda
- Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuka Hirabuki
- Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Taiki Takeuchi
- Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takumi Kagawa
- Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tsuyoshi Yokoi
- Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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12
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Umesalma S, Kaemmer CA, Kohlmeyer JL, Letney B, Schab AM, Reilly JA, Sheehy RM, Hagen J, Tiwari N, Zhan F, Leidinger MR, O'Dorisio TM, Dillon J, Merrill RA, Meyerholz DK, Perl AL, Brown BJ, Braun TA, Scott AT, Ginader T, Taghiyev AF, Zamba GK, Howe JR, Strack S, Bellizzi AM, Narla G, Darbro BW, Quelle FW, Quelle DE. RABL6A inhibits tumor-suppressive PP2A/AKT signaling to drive pancreatic neuroendocrine tumor growth. J Clin Invest 2019; 129:1641-1653. [PMID: 30721156 DOI: 10.1172/jci123049] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 01/24/2019] [Indexed: 12/15/2022] Open
Abstract
Hyperactivated AKT/mTOR signaling is a hallmark of pancreatic neuroendocrine tumors (PNETs). Drugs targeting this pathway are used clinically, but tumor resistance invariably develops. A better understanding of factors regulating AKT/mTOR signaling and PNET pathogenesis is needed to improve current therapies. We discovered that RABL6A, a new oncogenic driver of PNET proliferation, is required for AKT activity. Silencing RABL6A caused PNET cell-cycle arrest that coincided with selective loss of AKT-S473 (not T308) phosphorylation and AKT/mTOR inactivation. Restoration of AKT phosphorylation rescued the G1 phase block triggered by RABL6A silencing. Mechanistically, loss of AKT-S473 phosphorylation in RABL6A-depleted cells was the result of increased protein phosphatase 2A (PP2A) activity. Inhibition of PP2A restored phosphorylation of AKT-S473 in RABL6A-depleted cells, whereas PP2A reactivation using a specific small-molecule activator of PP2A (SMAP) abolished that phosphorylation. Moreover, SMAP treatment effectively killed PNET cells in a RABL6A-dependent manner and suppressed PNET growth in vivo. The present work identifies RABL6A as a new inhibitor of the PP2A tumor suppressor and an essential activator of AKT in PNET cells. Our findings offer what we believe is a novel strategy of PP2A reactivation for treatment of PNETs as well as other human cancers driven by RABL6A overexpression and PP2A inactivation.
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Affiliation(s)
| | | | | | | | | | | | - Ryan M Sheehy
- Department of Pharmacology.,Free Radical & Radiation Biology Training Program
| | | | | | | | - Mariah R Leidinger
- Department of Pathology, in the College of Medicine, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
| | | | | | | | - David K Meyerholz
- Department of Pathology, in the College of Medicine, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
| | - Abbey L Perl
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
| | | | | | | | | | - Agshin F Taghiyev
- Pediatrics, Colleges of Medicine, Engineering, or Public Health, University of Iowa, Iowa City, Iowa, USA
| | | | | | | | - Andrew M Bellizzi
- Department of Pathology, in the College of Medicine, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
| | - Goutham Narla
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Benjamin W Darbro
- Pediatrics, Colleges of Medicine, Engineering, or Public Health, University of Iowa, Iowa City, Iowa, USA
| | | | - Dawn E Quelle
- Department of Pharmacology.,Molecular Medicine Graduate Program.,Free Radical & Radiation Biology Training Program.,Department of Pathology, in the College of Medicine, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
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13
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IPP-1 controls Akt/CREB phosphorylation extension in A 2a adenosine receptor signaling cascade in MIN6 pancreatic β-cell line. Eur J Pharmacol 2019; 850:88-96. [PMID: 30772395 DOI: 10.1016/j.ejphar.2019.02.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 11/23/2022]
Abstract
Signaling through A2a adenosine receptor specifically prevent pancreatic β-cells (PBCs) loses under diabetogenic conditions. However, signaling mediators of this receptor in PBCs remained unidentified. Thus, we aimed to investigate the possible involvement of PKA/Akt/IPP-1/CREB pathway in MIN6 β-cells. In addition, we investigated IPP-1 role in A2a receptor signaling pathway. The expression of A2a receptor in MIN6 cell line was evaluated by RT-PCR and its functionality confirmed by quantification of cAMP in response to the CGS 21680, an A2a receptor agonist. MTT and Brdu assays were used to evaluate cell viability and proliferation, respectively. PKA activity and insulin release were evaluated using ELISA methods. P-Akt/Akt, p-IPP-1/IPP-1, and p-CREB/CREB levels were assessed using western blotting. IPP-1 knock down assessments was performed using specific siRNA. Our result revealed that MIN6 cells express A2a receptor which actively increased cAMP levels (with EC50 = 2.41 µM) and PKA activity. Activation of this receptor increased cell viability, proliferation and insulin release. Moreover, we mentioned A2a receptor stimulation increased p-Akt, p-IPP-1, and p-CREB levels in dose (max at 10 µM of CGS 21680) and time (max at 30 min after CGS 21680 treatment) dependent manner. Interestingly, herein, we found in IPP-1 knocked down cells, A2a receptor failed to activate Akt and CREB. Altogether, we mentioned that in MIN6 cells A2a receptor increase cell viability, proliferation and insulin release through PKA/Akt/IPP-1/CREB signaling pathway. In addition, we conclude A2a receptor signaling through this pathway is dependent to activation of IPP-1.
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14
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Protein Phosphatase 1 Regulatory Subunit SDS22 Inhibits Breast Cancer Cell Tumorigenesis by Functioning as a Negative Regulator of the AKT Signaling Pathway. Neoplasia 2018; 21:30-40. [PMID: 30500680 PMCID: PMC6262785 DOI: 10.1016/j.neo.2018.10.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 01/22/2023] Open
Abstract
Protein phosphatases play a crucial role in cell cycle progression, cell survival, cellular signaling, and genomic integrity. The protein phosphatase 1 (PP1) regulatory subunit SDS22 plays a significant role in cell cycle progression. A recent study showed that SDS22 plays a vital role in epithelial integrity and tumor suppression in Drosophila. However, its tumor suppressive activity remains obscure in the mammalian system. Here, for the first time, we show that SDS22 inhibits the growth of breast cancer cells through induction of apoptosis. SDS22 negatively regulates the AKT kinase signaling pathway through PP1. SDS22 associates predominantly with AKT and dephosphorylates the phospho Thr308 and phospho Ser473 through PP1 and hence abrogates the cell migration, invasion, and tumor growth. Thus, our study deciphers the long-standing question of how PP1 negatively regulates the AKT signaling pathway. Further, we observed a significant converse correlation in the expression levels of SDS22 and phospho form of AKT with reduced levels of SDS22 in the higher grades of cancer. Overall, our results suggest that SDS22 could be a putative tumor suppressor and replenishment of SDS22 would be an important strategy to restrict the tumor progression.
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15
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Sugano E, Edwards G, Saha S, Wilmott LA, Grambergs RC, Mondal K, Qi H, Stiles M, Tomita H, Mandal N. Overexpression of acid ceramidase (ASAH1) protects retinal cells (ARPE19) from oxidative stress. J Lipid Res 2018; 60:30-43. [PMID: 30413652 DOI: 10.1194/jlr.m082198] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 10/26/2018] [Indexed: 01/08/2023] Open
Abstract
Over 11 million people in the United States alone have some form of age-related macular degeneration (AMD). Oxidative stress, cell death, and the degeneration of retinal pigment epithelial (RPE) cells contribute to AMD pathology. Recent evidence suggests that ceramide (Cer), a cellular sphingolipid mediator that acts as a second messenger to induce apoptosis, might play a role in RPE cell death. The lysosomal breakdown of Cer by acid ceramidase [N-acylsphingosine amidohydrolase (ASAH)1] into sphingosine (Sph) is the major source for Sph 1-phosphate production, which has an opposing role to Cer and provides cytoprotection. Here, we investigated the role of Cer in human RPE-derived ARPE19 cells under hydrogen peroxide-induced oxidative stress, and show that Cer and hexosyl-Cer levels increase in the oxidatively stressed ARPE19 cells, which can be prevented by overexpression of lysosomal ASAH1. This study demonstrates that oxidative stress generates sphingolipid death mediators in retinal cells and that induction of ASAH1 could rescue retinal cells from oxidative stress by hydrolyzing excess Cers.
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Affiliation(s)
- Eriko Sugano
- Division of Science and Engineering, Iwate University, Morioka 020-8551, Japan
| | - Genea Edwards
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Saikat Saha
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Lynda A Wilmott
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Richard C Grambergs
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Koushik Mondal
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163
| | - Hui Qi
- Department of Ophthalmology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104
| | - Megan Stiles
- Department of Ophthalmology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104
| | - Hiroshi Tomita
- Division of Science and Engineering, Iwate University, Morioka 020-8551, Japan
| | - Nawajes Mandal
- Departments of Ophthalmology University of Tennessee Health Science Center, Memphis, TN 38163 .,Department of Ophthalmology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104.,Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163
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16
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Protein Phosphatase 1α and Cofilin Regulate Nuclear Translocation of NF-κB and Promote Expression of the Anti-Inflammatory Cytokine Interleukin-10 by T Cells. Mol Cell Biol 2018; 38:MCB.00041-18. [PMID: 30181394 DOI: 10.1128/mcb.00041-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 08/23/2018] [Indexed: 02/07/2023] Open
Abstract
While several protein serine/threonine kinases control cytokine production by T cells, the roles of serine/threonine phosphatases are largely unexplored. Here, we analyzed the involvement of protein phosphatase 1α (PP1α) in cytokine synthesis following costimulation of primary human T cells. Small interfering RNA (siRNA)-mediated knockdown of PP1α (PP1KD) or expression of a dominant negative PP1α (D95N-PP1) drastically diminished interleukin-10 (IL-10) production. Focusing on a key transcriptional activator of human IL-10, we demonstrate that nuclear translocation of NF-κB was significantly inhibited in PP1KD or D95N-PP1 cells. Interestingly, knockdown of cofilin, a known substrate of PP1 containing a nuclear localization signal, also prevented nuclear accumulation of NF-κB. Expression of a constitutively active nonphosphorylatable S3A-cofilin in D95N-PP1 cells restored nuclear translocation of NF-κB and IL-10 expression. Subpopulation analysis revealed that defective nuclear translocation of NF-κB was most prominent in CD4+ CD45RA- CXCR3- T cells that included IL-10-producing TH2 cells. Together these findings reveal novel functions for PP1α and its substrate cofilin in T cells namely the regulation of the nuclear translocation of NF-κB and promotion of IL-10 production. These data suggest that stimulation of PP1α could limit the overwhelming immune responses seen in chronic inflammatory diseases.
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17
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Szymonowicz K, Oeck S, Malewicz NM, Jendrossek V. New Insights into Protein Kinase B/Akt Signaling: Role of Localized Akt Activation and Compartment-Specific Target Proteins for the Cellular Radiation Response. Cancers (Basel) 2018; 10:cancers10030078. [PMID: 29562639 PMCID: PMC5876653 DOI: 10.3390/cancers10030078] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 12/19/2022] Open
Abstract
Genetic alterations driving aberrant activation of the survival kinase Protein Kinase B (Akt) are observed with high frequency during malignant transformation and cancer progression. Oncogenic gene mutations coding for the upstream regulators or Akt, e.g., growth factor receptors, RAS and phosphatidylinositol-3-kinase (PI3K), or for one of the three Akt isoforms as well as loss of the tumor suppressor Phosphatase and Tensin Homolog on Chromosome Ten (PTEN) lead to constitutive activation of Akt. By activating Akt, these genetic alterations not only promote growth, proliferation and malignant behavior of cancer cells by phosphorylation of various downstream signaling molecules and signaling nodes but can also contribute to chemo- and radioresistance in many types of tumors. Here we review current knowledge on the mechanisms dictating Akt’s activation and target selection including the involvement of miRNAs and with focus on compartmentalization of the signaling network. Moreover, we discuss recent advances in the cross-talk with DNA damage response highlighting nuclear Akt target proteins with potential involvement in the regulation of DNA double strand break repair.
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Affiliation(s)
- Klaudia Szymonowicz
- Institute of Cell Biology (Cancer Research), University of Duisburg-Essen Medical School, 45122 Essen, Germany.
| | - Sebastian Oeck
- Institute of Cell Biology (Cancer Research), University of Duisburg-Essen Medical School, 45122 Essen, Germany.
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Nathalie M Malewicz
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Verena Jendrossek
- Institute of Cell Biology (Cancer Research), University of Duisburg-Essen Medical School, 45122 Essen, Germany.
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18
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Suppression of c-Myc and RRM2 expression in pancreatic cancer cells by the sphingosine kinase-2 inhibitor ABC294640. Oncotarget 2018; 7:60181-60192. [PMID: 27517489 PMCID: PMC5312377 DOI: 10.18632/oncotarget.11112] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 07/06/2016] [Indexed: 01/07/2023] Open
Abstract
Pancreatic cancer remains extremely difficult to treat, with the average lifespan following diagnosis being only 3-6 months, resulting in a death to incidence ratio of 0.94. A major reason for this high mortality rate is resistance to the main chemotherapeutic agent used to treat this disease, gemcitabine. Alterations in nucleoside and gemcitabine metabolism, specifically over-expression of ribonucleotide reductase, have been implicated as a major mechanism of resistance to this drug. Here, we show that inhibition of sphingosine kinase-2 by the specific inhibitor ABC294640 is synergistically cytotoxic with gemcitabine toward three human pancreatic cancer cell lines. Treatment with ABC294640 results in decreased expression of both RRM2 and MYC in all three cell lines. Additionally, expression of c-Myc protein and phosphorylation of Rb at S780 both decrease in a dose-dependent manner in response to ABC294640, while acetylation of H3-K9 and p21 levels increase. Pretreatment with the protein phosphatase 1 inhibitor okadaic acid or the ceramide synthase inhibitor fumonisin B1 fails to prevent the effects of ABC294640 on Rb phosphorylation. These data indicate a role for sphingosine kinase-2 in E2F and c-Myc mediated transcription through alteration of histone acetylation and p21 expression. These effects of ABC294640 suggest that it may be an effective agent for pancreatic cancer, particularly in combination with gemcitabine.
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19
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Bonneau B, Ando H, Kawaai K, Hirose M, Takahashi-Iwanaga H, Mikoshiba K. IRBIT controls apoptosis by interacting with the Bcl-2 homolog, Bcl2l10, and by promoting ER-mitochondria contact. eLife 2016; 5. [PMID: 27995898 PMCID: PMC5173324 DOI: 10.7554/elife.19896] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 11/24/2016] [Indexed: 12/15/2022] Open
Abstract
IRBIT is a molecule that interacts with the inositol 1,4,5-trisphosphate (IP3)-binding pocket of the IP3 receptor (IP3R), whereas the antiapoptotic protein, Bcl2l10, binds to another part of the IP3-binding domain. Here we show that Bcl2l10 and IRBIT interact and exert an additive inhibition of IP3R in the physiological state. Moreover, we found that these proteins associate in a complex in mitochondria-associated membranes (MAMs) and that their interplay is involved in apoptosis regulation. MAMs are a hotspot for Ca2+ transfer between endoplasmic reticulum (ER) and mitochondria, and massive Ca2+ release through IP3R in mitochondria induces cell death. We found that upon apoptotic stress, IRBIT is dephosphorylated, becoming an inhibitor of Bcl2l10. Moreover, IRBIT promotes ER mitochondria contact. Our results suggest that by inhibiting Bcl2l10 activity and promoting contact between ER and mitochondria, IRBIT facilitates massive Ca2+ transfer to mitochondria and promotes apoptosis. This work then describes IRBIT as a new regulator of cell death.
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Affiliation(s)
- Benjamin Bonneau
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
| | - Hideaki Ando
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
| | - Katsuhiro Kawaai
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
| | - Matsumi Hirose
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
| | | | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
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20
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Sharma P, Arias EB, Cartee GD. Protein Phosphatase 1-α Regulates AS160 Ser588 and Thr642 Dephosphorylation in Skeletal Muscle. Diabetes 2016; 65:2606-17. [PMID: 27246912 PMCID: PMC5001182 DOI: 10.2337/db15-0867] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 05/23/2016] [Indexed: 01/09/2023]
Abstract
Akt substrate of 160 kDa (AS160) phosphorylation on Thr(642) and Ser(588) by Akt is essential for insulin's full effect on glucose transport. However, protein phosphorylation is determined by the balance of actions by kinases and phosphatases, and the specific phosphatase(s) controlling AS160 dephosphorylation is (are) unknown. Accordingly, we assessed roles of highly expressed skeletal muscle serine/threonine phosphatases (PP1, PP2A, PP2B, and PP2C) on AS160 dephosphorylation. Preliminary screening of candidate phosphatases used an AS160 dephosphorylation assay. Lysates from insulin-stimulated skeletal muscle were treated with pharmacological phosphatase inhibitors and assessed for AS160 Ser(588) and Thr(642) dephosphorylation. AS160 dephosphorylation on both phosphorylation sites was unaltered by PP2B or PP2C inhibitors. Okadaic acid (low dose inhibits PP2A; high dose inhibits PP1) delayed AS160 Ser(588) (both doses) and Thr(642) (high dose only) dephosphorylation concomitant with greater Akt phosphorylation (both doses). AS160 was coimmunoprecipitated with PP1-α but not with PP1-β, PP1-γ1, or PP2A. Recombinant inhibitor-2 protein (a selective PP1 inhibitor) delayed AS160 dephosphorylation on both phosphorylation sites without altering Akt phosphorylation. Furthermore, knockdown of PP1-α but not PP1-β or PP1-γ1 by small interfering RNA caused greater AS160 Ser(588) and Thr(642) phosphorylation concomitant with unaltered Akt phosphorylation. Together, these results identified PP1-α as a regulator of AS160 Thr(642) and Ser(588) dephosphorylation in skeletal muscle.
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Affiliation(s)
- Pragya Sharma
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI
| | - Edward B Arias
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI
| | - Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI Institute of Gerontology, University of Michigan, Ann Arbor, MI
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21
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Wang L, Zhao J, Ren J, Hall KH, Moorman JP, Yao ZQ, Ning S. Protein phosphatase 1 abrogates IRF7-mediated type I IFN response in antiviral immunity. Eur J Immunol 2016; 46:2409-2419. [PMID: 27469204 DOI: 10.1002/eji.201646491] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/12/2016] [Accepted: 07/26/2016] [Indexed: 02/04/2023]
Abstract
Interferon (IFN) regulatory factor 7 (IRF7) plays a key role in the production of IFN-α in response to viral infection, and phosphorylation at IRF7 C-terminal serine sites is prelude to its function. However, phosphatases that negatively regulate IRF7 phosphorylation and activity have not been reported. In this study, we have identified a conserved protein phosphatase 1 (PP1)-binding motif in human and mouse IRF7 proteins, and shown that PP1 physically interacts with IRF7. Exogenous expression of PP1 subunits (PP1α, β, or γ) ablates IKKε-stimulated IRF7 phosphorylation and dramatically attenuates IRF7 transcriptional activity. Inhibition of PP1 activity significantly increases IRF7 phosphorylation and IRF7-mediated IFN-α production in response to Newcastle disease virus (NDV) infection or Toll-like receptor 7 (TLR7) challenge, leading to impaired viral replication. In addition, IFN treatment, TLR challenges and viral infection induce PP1 expression. Our findings disclose for the first time a pivotal role for PP1 in impeding IRF7-mediated IFN-α production in host immune responses.
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Affiliation(s)
- Ling Wang
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA
| | - Juan Zhao
- Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA
| | - Junping Ren
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA
| | - Kenton H Hall
- Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA
| | - Jonathan P Moorman
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA.,Hepatitis (HCV/HIV) Program, James H Quillen VA Medical Center, Johnson City, TN, USA
| | - Zhi Q Yao
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA.,Hepatitis (HCV/HIV) Program, James H Quillen VA Medical Center, Johnson City, TN, USA
| | - Shunbin Ning
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA. .,Department of Internal Medicine, East Tennessee State University, Quillen College of Medicine, Johnson City, TN, USA.
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22
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Huang SH, Lien JC, Chen CJ, Liu YC, Wang CY, Ping CF, Lin YF, Huang AC, Lin CW. Antiviral Activity of a Novel Compound CW-33 against Japanese Encephalitis Virus through Inhibiting Intracellular Calcium Overload. Int J Mol Sci 2016; 17:ijms17091386. [PMID: 27563890 PMCID: PMC5037666 DOI: 10.3390/ijms17091386] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 07/26/2016] [Accepted: 08/18/2016] [Indexed: 01/31/2023] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, has five genotypes (I, II, III, IV, and V). JEV genotype I circulates widely in some Asian countries. However, current JEV vaccines based on genotype III strains show low neutralizing capacities against genotype I variants. In addition, JE has no specific treatment, except a few supportive treatments. Compound CW-33, an intermediate synthesized derivative of furoquinolines, was investigated for its antiviral activities against JEV in this study. CW-33 exhibited the less cytotoxicity to Syrian baby hamster kidney (BHK-21) and human medulloblastoma (TE761) cells. CW-33 dose-dependently reduced the cytopathic effect and apoptosis of JEV-infected cells. Supernatant virus yield assay pinpointed CW-33 as having potential anti-JEV activity with IC50 values ranging from 12.7 to 38.5 μM. Time-of-addition assay with CW-33 indicated that simultaneous and post-treatment had no plaque reduction activity, but continuous and simultaneous treatments proved to have highly effective antiviral activity, with IC50 values of 32.7 and 48.5 μM, respectively. CW-33 significantly moderated JEV-triggered Ca2+ overload, which correlated with the recovery of mitochondria membrane potential as well as the activation of Akt/mTOR and Jak/STAT1 signals in treated infected cells. Phosphopeptide profiling by LC-MS/MS revealed that CW-33 upregulated proteins from the enzyme modulator category, such as protein phosphatase inhibitor 2 (I-2), Rho GTPase-activating protein 35, ARF GTPase-activating protein GIT2, and putative 3-phosphoinositide-dependent protein kinase 2. These enzyme modulators identified were associated with the activation of Akt/mTOR and Jak/STAT1 signals. Meanwhile, I-2 treatment substantially inhibited the apoptosis of JEV-infected cells. The results demonstrated that CW-33 exhibited a significant potential in the development of anti-JEV agents.
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Affiliation(s)
- Su-Hua Huang
- Department of Biotechnology, Asia University, Wufeng, Taichung 413, Taiwan.
| | - Jin-Cherng Lien
- School of Pharmacy, China Medical University, Taichung 404, Taiwan.
| | - Chao-Jung Chen
- Proteomics Core Laboratory, Department of Medical Research, China Medical University Hospital, Taichung 404, Taiwan.
| | - Yu-Ching Liu
- Proteomics Core Laboratory, Department of Medical Research, China Medical University Hospital, Taichung 404, Taiwan.
| | - Ching-Ying Wang
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung 404, Taiwan.
| | - Chia-Fong Ping
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung 404, Taiwan.
| | - Yu-Fong Lin
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung 404, Taiwan.
| | - An-Cheng Huang
- Department of Nursing, St. Mary's Junior College of Medicine, Nursing and Management, Yilan County 266, Taiwan.
| | - Cheng-Wen Lin
- Department of Biotechnology, Asia University, Wufeng, Taichung 413, Taiwan.
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung 404, Taiwan.
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Rahman A, Thayyullathil F, Pallichankandy S, Galadari S. Hydrogen peroxide/ceramide/Akt signaling axis play a critical role in the antileukemic potential of sanguinarine. Free Radic Biol Med 2016; 96:273-89. [PMID: 27154977 DOI: 10.1016/j.freeradbiomed.2016.05.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/27/2016] [Accepted: 05/01/2016] [Indexed: 12/29/2022]
Abstract
Dysregulation of apoptosis is a prime hallmark of leukemia. Therefore, drugs which restore the sensitivity of leukemic cells to apoptotic stimuli are promising candidates in the treatment of leukemia. Recently, we have demonstrated that sanguinarine (SNG), a benzophenanthridine alkaloid, isolated from Sanguinaria canadensis induces ROS-dependent ERK1/2 activation and autophagic cell death in human malignant glioma cells (Pallichankandy et al., 2015; [43]). In this study, we investigated the antileukemic potential of SNG in vitro, and further examined the molecular mechanisms of SNG-induced cell death. In human leukemic cells, SNG activated apoptotic cell death pathway characterized by activation of caspase cascade, DNA fragmentation and down-regulation of anti-apoptotic proteins. Importantly, we have identified a crucial role for hydrogen peroxide (H2O2)-dependent ceramide (Cer) generation in the facilitation of SNG-induced apoptosis. Additionally, we have found that SNG inhibits Akt, a key anti-apoptotic protein kinase by dephosphorylating it at Ser(473), leading to the dephosphorylation of its downstream targets, GSK3β and mTOR. Interestingly, inhibition of Cer generation, using acid sphingomyelinase inhibitor, significantly reduced the SNG-induced Akt dephosphorylation and apoptosis, whereas, activation of Cer generation using inhibitors of acid ceramidase and glucosylceramide synthase enhanced it. Furthermore, using a group of ceramide activated protein phosphatases (CAPPs) inhibitor (calyculin A, Okadaic acid, and phosphatidic acid), the involvement of protein phosphatase 1 form of CAPP in SNG-induced Akt dephosphorylation and apoptosis was demonstrated. Altogether, these results underscore a critical role for H2O2-Cer-Akt signaling axis in the antileukemic action of SNG.
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Affiliation(s)
- Anees Rahman
- Cell Signaling Laboratory, Department of Biochemistry, College of Medicine and Health Sciences, UAE University, P.O. Box 17666, Al Ain, Abu Dhabi, United Arab Emirates.
| | - Faisal Thayyullathil
- Cell Signaling Laboratory, Department of Biochemistry, College of Medicine and Health Sciences, UAE University, P.O. Box 17666, Al Ain, Abu Dhabi, United Arab Emirates.
| | - Siraj Pallichankandy
- Cell Signaling Laboratory, Department of Biochemistry, College of Medicine and Health Sciences, UAE University, P.O. Box 17666, Al Ain, Abu Dhabi, United Arab Emirates.
| | - Sehamuddin Galadari
- Cell Signaling Laboratory, Department of Biochemistry, College of Medicine and Health Sciences, UAE University, P.O. Box 17666, Al Ain, Abu Dhabi, United Arab Emirates; Al Jalila Foundation Research Centre, P.O. Box 300100, Dubai, United Arab Emirates.
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24
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Nakahashi A, C. Siddegowda AK, Hammam MAS, Gowda SGB, Murai Y, Monde K. Stereochemical Study of Sphingosine by Vibrational Circular Dichroism. Org Lett 2016; 18:2327-30. [DOI: 10.1021/acs.orglett.6b00477] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Atsufumi Nakahashi
- Faculty
of Advanced Life
Science, Frontier Research Center for the Post-Genome Science and
Technology, Hokkaido University, Kita 21, Nishi 11, Sapporo 001-0021, Japan
| | - Ananda Kumar C. Siddegowda
- Faculty
of Advanced Life
Science, Frontier Research Center for the Post-Genome Science and
Technology, Hokkaido University, Kita 21, Nishi 11, Sapporo 001-0021, Japan
| | - Mostafa A. S. Hammam
- Faculty
of Advanced Life
Science, Frontier Research Center for the Post-Genome Science and
Technology, Hokkaido University, Kita 21, Nishi 11, Sapporo 001-0021, Japan
| | - Siddabasave Gowda B. Gowda
- Faculty
of Advanced Life
Science, Frontier Research Center for the Post-Genome Science and
Technology, Hokkaido University, Kita 21, Nishi 11, Sapporo 001-0021, Japan
| | - Yuta Murai
- Faculty
of Advanced Life
Science, Frontier Research Center for the Post-Genome Science and
Technology, Hokkaido University, Kita 21, Nishi 11, Sapporo 001-0021, Japan
| | - Kenji Monde
- Faculty
of Advanced Life
Science, Frontier Research Center for the Post-Genome Science and
Technology, Hokkaido University, Kita 21, Nishi 11, Sapporo 001-0021, Japan
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25
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Resveratrol augments ER stress and the cytotoxic effects of glycolytic inhibition in neuroblastoma by downregulating Akt in a mechanism independent of SIRT1. Exp Mol Med 2016; 48:e210. [PMID: 26891914 PMCID: PMC4892869 DOI: 10.1038/emm.2015.116] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 09/07/2015] [Accepted: 09/22/2015] [Indexed: 12/15/2022] Open
Abstract
Cancer cells typically display increased rates of aerobic glycolysis that are correlated with tumor aggressiveness and a poor prognosis. Targeting the glycolytic pathway has emerged as an attractive therapeutic route mainly because it should spare normal cells. Here, we evaluate the effects of combining the inhibition of glycolysis with application of the polyphenolic compound resveratrol (RSV) in neuroblastoma (NB) cancer cell lines. Inhibiting glycolysis with 2-deoxy-D-glucose (2-DG) significantly reduced NB cell viability and was associated with increased endoplasmic reticulum (ER) stress and Akt activity. Administration of 2-DG increased the expression of the ER molecular chaperones GRP78 and GRP94, the prodeath protein C/EBP homology protein (CHOP) and the phosphorylation of Akt at S473, T450 and T308. Combined treatment with both RSV and 2-DG reduced GRP78, GRP94 and Akt phosphorylation but increased CHOP and NB cell death when compared with the administration of 2-DG alone. The selective inhibition of Akt activity also decreased 2-DG-induced GRP78 and GRP94 expression and increased CHOP expression, suggesting that Akt can modulate ER stress. Protein phosphatase 1α (PP1α) was activated by RSV, as indicated by a reduction in PP1α phosphorylation at T320. Pretreatment of cells with tautomycin, a selective PP1α inhibitor, prevented the RSV-mediated decrease in Akt phosphorylation, suggesting that RSV enhances 2-DG-induced cell death by activating PP1 and downregulating Akt. The RSV-mediated inhibition of Akt in the presence of 2-DG was not prevented by the selective inhibition of SIRT1, a known target of RSV, indicating that the effects of RSV on this pathway are independent of SIRT1. We propose that RSV inhibits Akt activity by increasing PP1α activity, thereby potentiating 2-DG-induced ER stress and NB cell death.
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Abstract
Studies over the past two decades have identified ceramide as a multifunctional central molecule in the sphingolipid biosynthetic pathway. Given its diverse tumor suppressive activities, molecular understanding of ceramide action will produce fundamental insights into processes that limit tumorigenesis and may identify key molecular targets for therapeutic intervention. Ceramide can be activated by a diverse array of stresses such as heat shock, genotoxic damage, oxidative stress and anticancer drugs. Ceramide triggers a variety of tumor suppressive and anti-proliferative cellular programs such as apoptosis, autophagy, senescence, and necroptosis by activating or repressing key effector molecules. Defects in ceramide generation and metabolism in cancer contribute to tumor cell survival and resistance to chemotherapy. The potent and versatile anticancer activity profile of ceramide has motivated drug development efforts to (re-)activate ceramide in established tumors. This review focuses on our current understanding of the tumor suppressive functions of ceramide and highlights the potential downstream targets of ceramide which are involved in its tumor suppressive action.
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27
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Lackey BR, Gray SL. Identification of kinases, phosphatases, and phosphorylation sites in human and porcine spermatozoa. Syst Biol Reprod Med 2015; 61:345-52. [PMID: 26467841 DOI: 10.3109/19396368.2015.1089335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Multiple inter-connected signaling pathways, involving kinases and phosphatases, form a framework that controls sperm motility, function, and fertilizing ability. Methods that give a broad view of the proteomic landscape may prove valuable in uncovering new crosstalk connections, as well as in discovering new proteins within this regulatory framework. A multi-immunoblotting strategy was utilized to evaluate this concept on human and porcine spermatozoa samples. In human and porcine spermatozoa, a diversity of kinases were identified including protein kinase A (PKA), protein kinase B (PKB), isoforms of protein kinase C (PKC), calmodulin-dependent kinases (CAMK), casein kinase (CK), and isoforms of glycogen synthase kinase (GSK3). Several phosphatases, such as protein phosphatase (PP)-1, PP2A, PP2C, and mitogen activated protein kinase (MAPK) phosphatase (MKP-1), were identified in human spermatozoa. The phosphorylation epitopes recognized belonged to members of the MAPK family, in addition to α and β isoforms of GSK3 and cAMP response element binding protein (CREB). Proteomic approaches that allow a broad view may aid in understanding the crosstalk between signaling systems in spermatozoal physiology.
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Affiliation(s)
- Brett R Lackey
- a Endocrine Physiology Laboratory, AVS Department, Clemson University , Clemson , SC , USA
| | - Sandra L Gray
- a Endocrine Physiology Laboratory, AVS Department, Clemson University , Clemson , SC , USA
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28
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Akt kinase C-terminal modifications control activation loop dephosphorylation and enhance insulin response. Biochem J 2015. [PMID: 26201515 DOI: 10.1042/bj20150325] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The Akt protein kinase, also known as protein kinase B, plays key roles in insulin receptor signalling and regulates cell growth, survival and metabolism. Recently, we described a mechanism to enhance Akt phosphorylation that restricts access of cellular phosphatases to the Akt activation loop (Thr(308) in Akt1 or protein kinase B isoform alpha) in an ATP-dependent manner. In the present paper, we describe a distinct mechanism to control Thr(308) dephosphorylation and thus Akt deactivation that depends on intramolecular interactions of Akt C-terminal sequences with its kinase domain. Modifications of amino acids surrounding the Akt1 C-terminal mTORC2 (mammalian target of rapamycin complex 2) phosphorylation site (Ser(473)) increased phosphatase resistance of the phosphorylated activation loop (pThr(308)) and amplified Akt phosphorylation. Furthermore, the phosphatase-resistant Akt was refractory to ceramide-dependent dephosphorylation and amplified insulin-dependent Thr(308) phosphorylation in a regulated fashion. Collectively, these results suggest that the Akt C-terminal hydrophobic groove is a target for the development of agents that enhance Akt phosphorylation by insulin.
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29
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Cross Regulation Between cGMP-dependent Protein Kinase and Akt in Vasodilatation of Porcine Pulmonary Artery. J Cardiovasc Pharmacol 2014; 64:452-9. [DOI: 10.1097/fjc.0000000000000137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Rego A, Trindade D, Chaves SR, Manon S, Costa V, Sousa MJ, Côrte-Real M. The yeast model system as a tool towards the understanding of apoptosis regulation by sphingolipids. FEMS Yeast Res 2013; 14:160-78. [DOI: 10.1111/1567-1364.12096] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/02/2013] [Accepted: 09/06/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
- António Rego
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
- Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
| | - Dário Trindade
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
- CNRS; UMR5095; Université de Bordeaux 2; Bordeaux France
| | - Susana R. Chaves
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
| | - Stéphen Manon
- CNRS; UMR5095; Université de Bordeaux 2; Bordeaux France
| | - Vítor Costa
- Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
- Departamento de Biologia Molecular; Instituto de Ciências Biomédicas Abel Salazar; Universidade do Porto; Porto Portugal
| | - Maria João Sousa
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
| | - Manuela Côrte-Real
- Departamento de Biologia; Centro de Biologia Molecular e Ambiental; Universidade do Minho; Braga Portugal
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Vadlakonda L, Dash A, Pasupuleti M, Anil Kumar K, Reddanna P. The Paradox of Akt-mTOR Interactions. Front Oncol 2013; 3:165. [PMID: 23802099 PMCID: PMC3687210 DOI: 10.3389/fonc.2013.00165] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Accepted: 06/07/2013] [Indexed: 12/20/2022] Open
Abstract
The serine threonine protein kinase, Akt, is at the central hub of signaling pathways that regulates cell growth, differentiation, and survival. The reciprocal relation that exists between the two activating phosphorylation sites of Akt, T308 and S473, and the two mTOR complexes, C1 and C2, forms the central controlling hub that regulates these cellular functions. In our previous review “PI3Kinase (PI3K)-AKT-mTOR and Wnt signaling pathways in cell cycle” we discussed the reciprocal relation between mTORC1 and C2 complexes in regulating cell metabolism and cell cycle progression in cancer cells. We present in this article, a hypothesis that activation of Akt-T308 phosphorylation in the presence of high ATP:AMP ratio promotes the stability of its phosphorylations and activates mTORC1 and the energy consuming biosynthetic processes. Depletion of energy leads to inactivation of mTORC1, activation of AMPK, FoxO, and promotes constitution of mTORC2 that leads to phosphorylation of Akt S473. Akt can also be activated independent of PI3K; this appears to have an advantage under situations like dietary restrictions, where insulin/insulin growth factor signaling could be a casualty.
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Acid ceramidase induces sphingosine kinase 1/S1P receptor 2-mediated activation of oncogenic Akt signaling. Oncogenesis 2013; 2:e49. [PMID: 23732709 PMCID: PMC3740300 DOI: 10.1038/oncsis.2013.14] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Acid ceramidase (AC) is overexpressed in most prostate tumors and confers oncogenic phenotypes to prostate cancer cells. AC modulates the cellular balance between ceramide, sphingosine and sphingosine 1-phosphate (S1P). These bioactive sphingolipids have diverse, powerful and often oppositional impacts on cell signaling, including the activation status of the oncogenic kinase Akt. Our studies show that AC expression correlates with phosphorylation of Akt in human prostate tumors, and elevation of phosphorylated Akt in tumor versus patient-matched benign tissue is contingent upon AC elevation. Investigation of the mechanism for AC-induced Akt activation revealed that AC activates Akt through sphingosine kinase 1 (SphK1)-derived generation of S1P. This signaling pathway proceeds through S1P receptor 2 (S1PR2)-dependent stimulation of PI3K. Functionally, AC-overexpressing cells are insensitive to cytotoxic chemotherapy, however, these cells are more susceptible to targeted inhibition of Akt. AC-overexpressing cells proliferate more rapidly than control cells and form more colonies in soft agar; however, these effects are profoundly sensitive to Akt inhibition, demonstrating increased dependence on Akt signaling for the oncogenic phenotypes of AC-overexpressing cells. These observations may have clinical implications for targeted therapy as PI3K and Akt inhibitors emerge from clinical trials.
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33
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Thayyullathil F, Pallichankandy S, Rahman A, Kizhakkayil J, Chathoth S, Patel M, Galadari S. Caspase-3 mediated release of SAC domain containing fragment from Par-4 is necessary for the sphingosine-induced apoptosis in Jurkat cells. J Mol Signal 2013; 8:2. [PMID: 23442976 PMCID: PMC3599610 DOI: 10.1186/1750-2187-8-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 02/23/2013] [Indexed: 12/26/2022] Open
Abstract
Background Prostate apoptosis response-4 (Par-4) is a tumor-suppressor protein that selectively activates and induces apoptosis in cancer cells, but not in normal cells. The cancer specific pro-apoptotic function of Par-4 is encoded in its centrally located SAC (Selective for Apoptosis induction in Cancer cells) domain (amino acids 137–195). The SAC domain itself is capable of nuclear entry, caspase activation, inhibition of NF-κB activity, and induction of apoptosis in cancer cells. However, the precise mechanism(s) of how the SAC domain is released from Par-4, in response to apoptotic stimulation, is not well explored. Results In this study, we demonstrate for the first time that sphingosine (SPH), a member of the sphingolipid family, induces caspase-dependant cleavage of Par-4, leading to the release of SAC domain containing fragment from it. Par-4 is cleaved at the EEPD131G site on incubation with caspase-3 in vitro, and by treating cells with several anti-cancer agents. The caspase-3 mediated cleavage of Par-4 is blocked by addition of the pan-caspase inhibitor z-VAD-fmk, caspase-3 specific inhibitor Ac-DEVD-CHO, and by introduction of alanine substitution for D131 residue. Moreover, suppression of SPH-induced Akt dephosphorylation also abrogated the caspase dependant cleavage of Par-4. Conclusion Evidence provided here shows that Par-4 is cleaved by caspase-3 during SPH-induced apoptosis. Cleavage of Par-4 leads to the generation of SAC domain containing fragment which may possibly be essential and sufficient to induce or augment apoptosis in cancer cells.
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Affiliation(s)
- Faisal Thayyullathil
- Cell Signaling Laboratory, Department of Biochemistry, College of Medicine and Health Sciences, UAE University, P,O, Box 17666, Al Ain, Abu Dhabi, UAE.
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Kizhakkayil J, Thayyullathil F, Chathoth S, Hago A, Patel M, Galadari S. Glutathione regulates caspase-dependent ceramide production and curcumin-induced apoptosis in human leukemic cells. Free Radic Biol Med 2012; 52:1854-64. [PMID: 22387197 DOI: 10.1016/j.freeradbiomed.2012.02.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 02/20/2012] [Accepted: 02/22/2012] [Indexed: 10/28/2022]
Abstract
Depletion of intracellular glutathione (GSH) is the prime hallmark of the progression of apoptosis. Previously, we reported that curcumin induces reactive oxygen species (ROS)-mediated depletion of GSH, which leads to caspase-dependent and independent apoptosis in mouse fibroblast cells (F. Thayyullathil et al., Free Radic. Biol. Med.45, 1403-1412, 2008). In this study, we investigated the antileukemic potential of curcumin in vitro, and we further examined the molecular mechanisms of curcumin-induced apoptosis in human leukemic cells. Curcumin suppresses the growth of human leukemic cells via ROS-independent GSH depletion, which leads to caspase activation, inhibition of sphingomyelin synthase (SMS) activity, and induction of ceramide (Cer) generation. Pretreatment of leukemic cells with carbobenzoxy-Val-Ala-Asp fluoromethylketone, a universal inhibitor of caspases, abrogates the SMS inhibition and Cer generation, and in turn prevents curcumin-induced cell death. Curcumin treatment of leukemic cells also downregulates the expression of the inhibitor of apoptosis proteins (IAPs), phospho-Akt, c-Myc, and cyclin D1. Extracellular supplementation with GSH attenuates curcumin-induced depletion of GSH, caspase-dependent inhibition of SMS, Cer generation, and downregulation of IAPs, whereas, L-D-buthionine sulfoximine, a widely used inhibitor of GSH synthesis, potentiates GSH depletion, Cer generation, and apoptosis induced by curcumin. Taken together, our findings provide evidence suggesting for the first time that GSH regulates caspase-dependent inhibition of SMS activity, Cer generation, and apoptosis induced by curcumin in human leukemic cells.
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Affiliation(s)
- Jaleel Kizhakkayil
- Cell Signaling Laboratory, Department of Biochemistry, Faculty of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
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35
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Kim J, Kim SY, Kang S, Yoon HR, Sun BK, Kang D, Kim JH, Song JJ. HSP27 modulates survival signaling networks in cells treated with curcumin and TRAIL. Cell Signal 2012; 24:1444-52. [PMID: 22449710 DOI: 10.1016/j.cellsig.2012.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 03/08/2012] [Accepted: 03/08/2012] [Indexed: 01/08/2023]
Abstract
The combination of curcumin and TRAIL and their role in enhancing apoptotic cell death has been reported by many studies. However, the exact molecular mechanism of apoptosis mediated by curcumin and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is not yet completely understood. In this study, we observed a close connection between dephosphorylated Akt and an increase in phosphorylated heat shock protein 27 (HSP27) during combined treatment with curcumin and TRAIL. Akt dephosphorylation was cumulatively regulated by protein phosphatase 1 (PP1), phosphoinositide-dependent kinase-1 (PDK1), and src. PP1 and PDK1 directly interacted with HSP27, whereas src indirectly interacted with HSP27 via the tumor necrosis factor receptor-associated factor 6 complex. In conclusion, HSP27 modulated cell survival by its interactions with various binding partners, depending on the level of phosphorylated HSP27.
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Affiliation(s)
- Jina Kim
- Institute for Cancer Research, College of Medicine, Yonsei University, Seoul, Republic of Korea
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36
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Glutathione selectively inhibits Doxorubicin induced phosphorylation of p53Ser¹⁵, caspase dependent ceramide production and apoptosis in human leukemic cells. Biochem Biophys Res Commun 2011; 411:1-6. [PMID: 21669188 DOI: 10.1016/j.bbrc.2011.05.156] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Accepted: 05/31/2011] [Indexed: 12/14/2022]
Abstract
Glutathione (GSH) is the most abundant non-protein antioxidant in mammalian cells. It has been implicated in playing an important role in different signal transduction pathways, and its depletion is an early hallmark in the progression of apoptosis in response to a number of proapoptotic stimuli. We have selectively investigated the role of GSH in cytotoxic response of Jurkat and Molt-4 human leukemic cells to the anti-cancer drug Doxorubicin. In this study, we have shown that extracellular supplementation of GSH to human leukemic cells renders them a resistant phenotype to Doxorubicin treatment. Glutathione pre-treatment inhibits Doxorubicin-induced p53Ser(15) phosphorylation, caspase dependent ceramide (Cer) generation, Poly (ADP-ribose) polymerase (PARP) cleavage, and DNA fragmentation. Taken together, these results indicate that the major cellular antioxidant GSH influences the chemotherapeutic efficacy of Doxorubicin towards human leukemic cells.
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