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Koroleva EV, Kornoushenko YV, Karpenko AD, Bosko IP, Siniutsich JV, Ignatovich ZV, Andrianov AM. In silico design and computational evaluation of novel 2-arylaminopyrimidine-based compounds as potential multi-targeted protein kinase inhibitors: application for the native and mutant (T315I) Bcr-Abl tyrosine kinase. J Biomol Struct Dyn 2023; 41:4065-4080. [PMID: 35470777 DOI: 10.1080/07391102.2022.2062784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 04/02/2022] [Indexed: 10/18/2022]
Abstract
An integrated computational approach to drug discovery was used to identify novel potential inhibitors of the native and mutant (T315I) Bcr-Abl tyrosine kinase, the enzyme playing a key role in the pathogenesis of chronic myeloid leukemia (CML). This approach included i) design of chimeric molecules based on the 2-arylaminopyrimidine fragment, the main pharmacophore of the Abl kinase inhibitors imatinib and nilotinib used in the clinic for the CML treatment, ii) molecular docking of these compounds with the ATP-binding site of the native and mutant Abl kinase, iii) refinement of the ligand-binding poses by the quantum chemical method PM7, iv) molecular dynamics simulations of the ligand/Abl complexes, and v) prediction of the ligand/Abl binding affinity in terms of scoring functions of molecular docking, machine learning, quantum chemistry, and molecular dynamics. As a result, five top-ranking compounds able to effectively block the enzyme catalytic site were identified. According to the data obtained, these compounds exhibit close modes of binding to the Abl kinase active site that are mainly provided by hydrogen bonds and multiple van der Waals contacts. The identified compounds show high binding affinity to the native and mutant Abl kinase comparable with the one calculated for the FDA-approved kinase-targeted inhibitors imatinib, nilotinib, and ponatinib used in the calculations as a positive control. The results obtained testify to the predicted drug candidates against CML may serve as good scaffolds for the design of novel anticancer agents able to target the ATP-binding pocket of the native and mutant Abl kinase.Communicated by Ramaswamy H. Sarma.
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MESH Headings
- Humans
- Adenosine Triphosphate/metabolism
- Antineoplastic Agents/chemistry
- Antineoplastic Agents/pharmacology
- Catalytic Domain
- Computer Simulation
- Drug Design
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/genetics
- Hydrogen Bonding
- Imatinib Mesylate/pharmacology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Ligands
- Machine Learning
- Molecular Docking Simulation
- Molecular Dynamics Simulation
- Mutant Proteins/antagonists & inhibitors
- Mutant Proteins/genetics
- Mutation
- Protein Kinase Inhibitors/chemistry
- Protein Kinase Inhibitors/pharmacology
- Pyrimidines/chemistry
- Pyrimidines/pharmacology
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Affiliation(s)
- Elena V Koroleva
- Institute of Chemistry of New Materials, National Academy of Sciences of Belarus, Minsk, Republic of Belarus
| | - Yuri V Kornoushenko
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Republic of Belarus
| | - Anna D Karpenko
- United Institute of Informatics Problems, National Academy of Sciences of Belarus, Minsk, Republic of Belarus
| | - Ivan P Bosko
- United Institute of Informatics Problems, National Academy of Sciences of Belarus, Minsk, Republic of Belarus
| | - Julia V Siniutsich
- Institute of Chemistry of New Materials, National Academy of Sciences of Belarus, Minsk, Republic of Belarus
| | - Zhanna V Ignatovich
- Institute of Chemistry of New Materials, National Academy of Sciences of Belarus, Minsk, Republic of Belarus
| | - Alexander M Andrianov
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Republic of Belarus
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2
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Choudhary P, Singh T, Amod A, Singh S. Evaluation of phytoconstituents of Tinospora cordifolia against K417N and N501Y mutant spike glycoprotein and main protease of SARS-CoV-2- an in silico study. J Biomol Struct Dyn 2023; 41:4106-4123. [PMID: 35467486 DOI: 10.1080/07391102.2022.2062787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 04/02/2022] [Indexed: 10/18/2022]
Abstract
Coronavirus disease 2019 (COVID-19) caused appalling conditions over the globe, which is currently faced by the entire human population. One of the primary reasons behind the uncontrollable situation is the lack of specific therapeutics. In such conditions, drug repurposing of available drugs (viz. Chloroquine, Lopinavir, etc.) has been proposed, but various clinical and preclinical investigations indicated the toxicity and adverse side effects of these drugs. This study explores the inhibition potency of phytochemicals from Tinospora cordifolia (Giloy) against SARS CoV-2 drugable targets (spike glycoprotein and Mpro proteins) using molecular docking and MD simulation studies. ADMET, virtual screening, MD simulation, postsimulation analysis (RMSD, RMSF, Rg, SASA, PCA, FES) and MM-PBSA calculations were carried out to predict the inhibition efficacy of the phytochemicals against SARS CoV-2 targets. Tinospora compounds showed better binding affinity than the corresponding reference. Their binding affinity ranges from -9.63 to -5.68 kcal/mole with spike protein and -10.27 to -7.25 kcal/mole with main protease. Further 100 ns exhaustive simulation studies and MM-PBSA calculations supported favorable and stable binding of them. This work identifies Nine Tinospora compounds as potential inhibitors. Among those, 7-desacetoxy-6,7-dehydrogedunin was found to inhibit both spike (7NEG) and Mpro (7MGS and 6LU7) proteins, and Columbin was found to inhibit selected spike targets (7NEG and 7NX7). In all the analyses, these compounds performed well and confirms the stable binding. Hence the identified compounds, advocated as potential inhibitors can be taken for further in vitro and in vivo experimental validation to determine their anti-SARS-CoV-2 potential.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Princy Choudhary
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Uttar Pradesh, India
| | - Tanu Singh
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Uttar Pradesh, India
| | - Ayush Amod
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Uttar Pradesh, India
| | - Sangeeta Singh
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Uttar Pradesh, India
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3
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Lei Y, Li Y, Tan Y, Qian Z, Zhou Q, Jia D, Sun Q. Novel Mechanistic Observations and NES-Binding Groove Features Revealed by the CRM1 Inhibitors Plumbagin and Oridonin. J Nat Prod 2021; 84:1478-1488. [PMID: 33890470 DOI: 10.1021/acs.jnatprod.0c01231] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The protein chromosome region maintenance 1 (CRM1) is an important nuclear export factor and drug target in diseases such as cancer and viral infections. Several plant-derived CRM1 inhibitors including plumbagin and oridonin possess potent antitumor activities. However, their modes of CRM1 inhibition remain unclear. Here, a multimutant CRM1 was engineered to enable crystallization of these two small molecules in its NES groove. Plumbagin and oridonin share the same three conjugation sites in CRM1. In solution, these two inhibitors targeted more CRM1 sites and inhibited its activity through promoting its aggregation, in addition to directly targeting the NES groove. While the plumbagin-bound NES groove resembles the NES-bound groove state, the oridonin complex reveals for the first time a more open NES groove. The observed greater NES groove dynamics may improve cargo loading through a "capture-and-tighten" mechanism. This work thus provides new insights on the mechanism of CRM1 inhibition by two natural products and a structural basis for further development of these or other CRM1 inhibitors.
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Affiliation(s)
- Yuqin Lei
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, People's Republic of China
| | - Yuling Li
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, People's Republic of China
| | - Yuping Tan
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, People's Republic of China
| | - Zhiyong Qian
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, People's Republic of China
| | - Qiao Zhou
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, People's Republic of China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, Division of Neurology, West China Second University Hospital, Sichuan University, Chengdu 610041, People's Republic of China
| | - Qingxiang Sun
- Department of Pathology, State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, and Collaborative Innovation Centre of Biotherapy, Chengdu 610041, People's Republic of China
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4
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Teng KW, Tsai ST, Hattori T, Fedele C, Koide A, Yang C, Hou X, Zhang Y, Neel BG, O'Bryan JP, Koide S. Selective and noncovalent targeting of RAS mutants for inhibition and degradation. Nat Commun 2021; 12:2656. [PMID: 33976200 PMCID: PMC8113534 DOI: 10.1038/s41467-021-22969-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/07/2021] [Indexed: 02/07/2023] Open
Abstract
Activating mutants of RAS are commonly found in human cancers, but to date selective targeting of RAS in the clinic has been limited to KRAS(G12C) through covalent inhibitors. Here, we report a monobody, termed 12VC1, that recognizes the active state of both KRAS(G12V) and KRAS(G12C) up to 400-times more tightly than wild-type KRAS. The crystal structures reveal that 12VC1 recognizes the mutations through a shallow pocket, and 12VC1 competes against RAS-effector interaction. When expressed intracellularly, 12VC1 potently inhibits ERK activation and the proliferation of RAS-driven cancer cell lines in vitro and in mouse xenograft models. 12VC1 fused to VHL selectively degrades the KRAS mutants and provides more extended suppression of mutant RAS activity than inhibition by 12VC1 alone. These results demonstrate the feasibility of selective targeting and degradation of KRAS mutants in the active state with noncovalent reagents and provide a starting point for designing noncovalent therapeutics against oncogenic RAS mutants.
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Affiliation(s)
- Kai Wen Teng
- Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
| | - Steven T Tsai
- Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
| | - Takamitsu Hattori
- Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, USA
| | - Carmine Fedele
- Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
| | - Akiko Koide
- Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
- Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Chao Yang
- Department of Chemistry, New York University, New York, NY, USA
| | - Xuben Hou
- Department of Chemistry, New York University, New York, NY, USA
| | - Yingkai Zhang
- Department of Chemistry, New York University, New York, NY, USA
| | - Benjamin G Neel
- Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA
- Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - John P O'Bryan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, USA
- Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - Shohei Koide
- Perlmutter Cancer Center, New York University Langone Health, New York, NY, USA.
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, USA.
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5
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Zhang N, Zheng B, Yao X, Huang X, Du J, Shen Y, Huang Z, Chen J, Lin Q, Lan W, Lin W, Ma W. Identification and characterization of a novel mutant isocitrate dehydrogenase 1 inhibitor for glioma treatment. Biochem Biophys Res Commun 2021; 551:38-45. [PMID: 33714758 DOI: 10.1016/j.bbrc.2021.02.112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 02/22/2021] [Indexed: 01/22/2023]
Abstract
Isocitrate dehydrogenase 1 (IDH1) mutant R132H, promoting the oncometabolite D-2-hydroxyglutarate (D2HG), is a driver mutation and an emerging therapeutic target in glioma. This study identified a novel mutant IDH1 inhibitor, WM17, by virtual screening and enzymatic confirmation. It could bind to and increase mutant IDH1 protein's thermostability in both endogenous heterozygous cells and exogenous overexpressed cells. Consequently, WM17 reversed the accumulation of D2HG and histone hypermethylation in IDH1 mutated cells. Finally, we concluded that WM17 significantly inhibited cell migration in IDH1 mutated glioma cells, although it has no apparent effect on cell proliferation. Further studies are guaranteed toward the development of WM17 as a therapeutic agent for IDH1 mutated glioma.
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Affiliation(s)
- Na Zhang
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Bowen Zheng
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Xiaojun Yao
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Xiaoming Huang
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Jingjing Du
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Yunfu Shen
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Zhe Huang
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Junhe Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Qianyu Lin
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Wenjian Lan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Wanjun Lin
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau
| | - Wenzhe Ma
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, 999078, Macau.
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6
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Zhi J, Zhang P, Zhang W, Ruan X, Tian M, Guo S, Zhang W, Zheng X, Zhao L, Gao M. Inhibition of BRAF Sensitizes Thyroid Carcinoma to Immunotherapy by Enhancing tsMHCII-mediated Immune Recognition. J Clin Endocrinol Metab 2021; 106:91-107. [PMID: 32936899 DOI: 10.1210/clinem/dgaa656] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 09/14/2020] [Indexed: 12/28/2022]
Abstract
CONTEXT Multiple mechanisms play roles in restricting the ability of T-cells to recognize and eliminate tumor cells. OBJECTIVE To identify immune escape mechanisms involved in papillary thyroid carcinoma (PTC) to optimize immunotherapy. SETTING AND DESIGN iTRAQ analysis was conducted to identify proteins differentially expressed in PTC samples with or without BRAFV600E mutation. Molecular mechanisms regulating tumor cell evasion were investigated by in vitro modulations of BRAF/MAPK and related pathways. The pathological significance of identified tumor-specific major histocompatibility complex class II (tsMHCII) molecules in mediating tumor cell immune escape and targeted immune therapy was further evaluated in a transgenic mouse model of spontaneous thyroid cancer. RESULTS Proteomic analysis showed that tsMHCII level was significantly lower in BRAFV600E-associated PTCs and negatively correlated with BRAF mutation status. Constitutive activation of BRAF decreased tsMHCII surface expression on tumor cells, which inhibited activation of CD4+ T-cells and led to immune escape. Pathway analysis indicated that the transforming growth factor (TGF)-β1/SMAD3-mediated repression of tsMHCII, which could be reversed by BRAF inhibition (BRAFi). Targeting this pathway with a combined therapy of BRAF inhibitor PLX4032 and anti-PD-1 antibody efficiently blocked tumor growth by increasing CD4+ T-cell infiltration in a transgenic PTC mouse model. CONCLUSIONS Our results suggest that BRAFV600E mutation in PTC impairs the expression of tsMHCII through the TGF-β1/SMAD3 pathway to enhance immune escape. Combined treatment with PLX4032 and anti-PD-1 antibody promotes recognition and elimination of PTC by the immune system in a pre-clinical mouse model, and therefore offers an effective therapeutic strategy for patients with advanced PTC.
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MESH Headings
- Animals
- Antineoplastic Agents, Immunological/administration & dosage
- Antineoplastic Agents, Immunological/pharmacology
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- CD4-Positive T-Lymphocytes/drug effects
- CD4-Positive T-Lymphocytes/physiology
- Cells, Cultured
- Cytotoxicity, Immunologic/drug effects
- Cytotoxicity, Immunologic/genetics
- Cytotoxicity, Immunologic/immunology
- Drug Synergism
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Expression Regulation, Neoplastic/immunology
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/physiology
- Humans
- Immunotherapy/methods
- Lymphocyte Activation/drug effects
- Lymphocyte Activation/genetics
- Mice
- Mice, Transgenic
- Mutant Proteins/antagonists & inhibitors
- Mutation, Missense
- Nivolumab/administration & dosage
- Nivolumab/pharmacology
- Organ Specificity/genetics
- Organ Specificity/immunology
- Protein Kinase Inhibitors/administration & dosage
- Protein Kinase Inhibitors/pharmacology
- Proto-Oncogene Proteins B-raf/antagonists & inhibitors
- Proto-Oncogene Proteins B-raf/genetics
- Thyroid Cancer, Papillary/drug therapy
- Thyroid Cancer, Papillary/genetics
- Thyroid Cancer, Papillary/immunology
- Thyroid Cancer, Papillary/pathology
- Thyroid Neoplasms/drug therapy
- Thyroid Neoplasms/genetics
- Thyroid Neoplasms/immunology
- Thyroid Neoplasms/pathology
- Tumor Escape/drug effects
- Tumor Escape/genetics
- Tumor Escape/immunology
- Vemurafenib/administration & dosage
- Vemurafenib/pharmacology
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Affiliation(s)
- Jingtai Zhi
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Peitao Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, People's Republic of China
| | - Wei Zhang
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Xianhui Ruan
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Mengran Tian
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Shicheng Guo
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin
- Center for Precision Medicine Research, Marshfield Clinic Research Institute, Marshfield, Wisconsin
| | - Weiyu Zhang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, People's Republic of China
- College of Pharmacy, Nankai University, Tianjin, People's Republic of China
| | - Xiangqian Zheng
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
| | - Li Zhao
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, People's Republic of China
| | - Ming Gao
- Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, People's Republic of China
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7
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Abstract
Cancer cells regulate key enzymes in the glycolytic pathway to control the glycolytic flux, which is necessary for their growth and proliferation. One of the enzymes is pyruvate kinase muscle isoform 2 (PKM2), which is allosterically regulated by various small molecules. Using detailed biochemical and kinetic studies, we demonstrate that cysteine inhibits wild-type (wt) PKM2 by shifting from an active tetramer to a mixture of a tetramer and a less active dimer/monomer equilibrium and that the inhibition is dependent on cysteine concentration. The cysteine-mediated PKM2 inhibition is reversed by fructose 1,6-bisphosphate, an allosteric activator of PKM2. Furthermore, kinetic studies using two dimeric PKM2 variants, S437Y PKM2 and G415R PKM2, show that the reversal is caused by the tetramerization of wtPKM2. The crystal structure of the wtPKM2-Cys complex was determined at 2.25 Å, which showed that cysteine is held to the amino acid binding site via its main chain groups, similar to that observed for phenylalanine, alanine, serine, and tryptophan. Notably, ligand binding studies using fluorescence and isothermal titration calorimetry show that the presence of phosphoenolpyruvate alters the binding affinities of amino acids for wtPKM2 and vice versa, thereby unravelling the existence of a functionally bidirectional coupling between the amino acid binding site and the active site of wtPKM2.
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Affiliation(s)
- Dhiraj Srivastava
- Department of Chemistry , The University of Iowa , Iowa City , Iowa 52242 , United States
| | - Suparno Nandi
- Department of Chemistry , The University of Iowa , Iowa City , Iowa 52242 , United States
| | - Mishtu Dey
- Department of Chemistry , The University of Iowa , Iowa City , Iowa 52242 , United States
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8
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Subramanian K, Mitusińska K, Raedts J, Almourfi F, Joosten HJ, Hendriks S, Sedelnikova SE, Kengen SWM, Hagen WR, Góra A, Martins Dos Santos VAP, Baker PJ, van der Oost J, Schaap PJ. Distant Non-Obvious Mutations Influence the Activity of a Hyperthermophilic Pyrococcus furiosus Phosphoglucose Isomerase. Biomolecules 2019; 9:biom9060212. [PMID: 31159273 PMCID: PMC6627849 DOI: 10.3390/biom9060212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/20/2019] [Accepted: 05/28/2019] [Indexed: 01/06/2023] Open
Abstract
The cupin-type phosphoglucose isomerase (PfPGI) from the hyperthermophilic archaeon Pyrococcus furiosus catalyzes the reversible isomerization of glucose-6-phosphate to fructose-6-phosphate. We investigated PfPGI using protein-engineering bioinformatics tools to select functionally-important residues based on correlated mutation analyses. A pair of amino acids in the periphery of PfPGI was found to be the dominant co-evolving mutation. The position of these selected residues was found to be non-obvious to conventional protein engineering methods. We designed a small smart library of variants by substituting the co-evolved pair and screened their biochemical activity, which revealed their functional relevance. Four mutants were further selected from the library for purification, measurement of their specific activity, crystal structure determination, and metal cofactor coordination analysis. Though the mutant structures and metal cofactor coordination were strikingly similar, variations in their activity correlated with their fine-tuned dynamics and solvent access regulation. Alternative, small smart libraries for enzyme optimization are suggested by our approach, which is able to identify non-obvious yet beneficial mutations.
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Affiliation(s)
- Kalyanasundaram Subramanian
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Karolina Mitusińska
- Biotechnology Center, Silesian University of Technology, ul. Krzywoustego 8, 44-100 Gliwice, Poland.
- Faculty of Chemistry, Silesian University of Technology, ul. Strzody 9, 44-100 Gliwice, Poland.
| | - John Raedts
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Feras Almourfi
- Saudi Human Genome Project, National Center of Genome Technology, King Abdulaziz City for Science and Technology (KACST), Riyadh 11442, Saudi Arabia.
| | - Henk-Jan Joosten
- Bio-Prodict, Nieuwe Marktstraat 54E, 6511 AA Nijmegen, The Netherlands.
| | - Sjon Hendriks
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Svetlana E Sedelnikova
- The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
| | - Servé W M Kengen
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Wilfred R Hagen
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
| | - Artur Góra
- Biotechnology Center, Silesian University of Technology, ul. Krzywoustego 8, 44-100 Gliwice, Poland.
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Patrick J Baker
- The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
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9
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Abstract
The tumour suppressor gene TP53 is the most frequently mutated gene in cancer. Wild-type p53 can suppress tumour development by multiple pathways. However, mutation of TP53 and the resultant inactivation of p53 allow evasion of tumour cell death and rapid tumour progression. The high frequency of TP53 mutation in tumours has prompted efforts to restore normal function of mutant p53 and thereby trigger tumour cell death and tumour elimination. Small molecules that can reactivate missense-mutant p53 protein have been identified by different strategies, and two compounds are being tested in clinical trials. Novel approaches for targeting TP53 nonsense mutations are also underway. This Review discusses recent progress in pharmacological reactivation of mutant p53 and highlights problems and promises with these strategies.
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Affiliation(s)
- Vladimir J N Bykov
- Karolinska Institutet, Department of Oncology-Pathology, Cancer Center Karolinska (CCK), SE-171 77 Stockholm, Sweden
| | - Sofi E Eriksson
- Karolinska Institutet, Department of Oncology-Pathology, Cancer Center Karolinska (CCK), SE-171 77 Stockholm, Sweden
| | - Julie Bianchi
- Karolinska Institutet, Department of Oncology-Pathology, Cancer Center Karolinska (CCK), SE-171 77 Stockholm, Sweden
| | - Klas G Wiman
- Karolinska Institutet, Department of Oncology-Pathology, Cancer Center Karolinska (CCK), SE-171 77 Stockholm, Sweden
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10
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Yue X, Zhao Y, Xu Y, Zheng M, Feng Z, Hu W. Mutant p53 in Cancer: Accumulation, Gain-of-Function, and Therapy. J Mol Biol 2017; 429:1595-1606. [PMID: 28390900 PMCID: PMC5663274 DOI: 10.1016/j.jmb.2017.03.030] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 03/31/2017] [Accepted: 03/31/2017] [Indexed: 12/19/2022]
Abstract
Tumor suppressor p53 plays a central role in tumor suppression. p53 is the most frequently mutated gene in human cancer, and over half of human cancers contain p53 mutations. Majority of p53 mutations in cancer are missense mutations, leading to the expression of full-length mutant p53 (mutp53) protein. While the critical role of wild-type p53 in tumor suppression has been firmly established, mounting evidence has demonstrated that many tumor-associated mutp53 proteins not only lose the tumor-suppressive function of wild-type p53 but also gain new activities to promote tumorigenesis independently of wild-type p53, termed gain-of-function. Mutant p53 protein often accumulates to very high levels in tumors, contributing to malignant progression. Recently, mutp53 has become an attractive target for cancer therapy. Further understanding of the mechanisms underlying mutp53 protein accumulation and gain-of-function will accelerate the development of targeted therapies for human cancer harboring mutp53. In this review, we summarize the recent advances in the studies on mutp53 protein accumulation and gain-of-function and targeted therapies for mutp53 in human cancer.
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Affiliation(s)
- Xuetian Yue
- Rutgers Cancer Institute of New Jersey, Rutgers, the State University of New Jersey, New Brunswick, NJ 08903, USA
| | - Yuhan Zhao
- Rutgers Cancer Institute of New Jersey, Rutgers, the State University of New Jersey, New Brunswick, NJ 08903, USA
| | - Yang Xu
- Department of Hematology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Min Zheng
- State Key Lab of Diagnostic and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Zhaohui Feng
- Rutgers Cancer Institute of New Jersey, Rutgers, the State University of New Jersey, New Brunswick, NJ 08903, USA; Department of Pharmacology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08903, USA.
| | - Wenwei Hu
- Rutgers Cancer Institute of New Jersey, Rutgers, the State University of New Jersey, New Brunswick, NJ 08903, USA; Department of Pharmacology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08903, USA.
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11
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Posch C, Vujic I, Monshi B, Sanlorenzo M, Weihsengruber F, Rappersberger K, Ortiz-Urda S. Searching for the Chokehold of NRAS Mutant Melanoma. J Invest Dermatol 2016; 136:1330-1336. [PMID: 27160069 DOI: 10.1016/j.jid.2016.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/01/2016] [Accepted: 03/08/2016] [Indexed: 12/19/2022]
Abstract
Up to 18% of melanomas harbor mutations in the neuroblastoma rat-sarcoma homolog (NRAS). Yet, decades of research aimed to interfere with oncogenic RAS signaling have been largely disappointing and have not resulted in meaningful clinical outputs. Recent advances in disease modeling, structural biology, and an improved understanding of RAS cycling as well as RAS signaling networks have renewed hope for developing strategies to selectively block hyperactive RAS function. This review discusses direct and indirect blocking of activated RAS with a focus on current and potential future therapeutic approaches for NRAS mutant melanoma.
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Affiliation(s)
- Christian Posch
- Department of Dermatology, Mt. Zion Cancer Research Center, University of California San Francisco, San Francisco, California, USA; Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Department of Dermatology, The Rudolfstiftung Hospital, Academic Teaching Hospital, Medical University Vienna, Vienna, Austria.
| | - Igor Vujic
- Department of Dermatology, Mt. Zion Cancer Research Center, University of California San Francisco, San Francisco, California, USA; Department of Dermatology, The Rudolfstiftung Hospital, Academic Teaching Hospital, Medical University Vienna, Vienna, Austria
| | - Babak Monshi
- Department of Dermatology, The Rudolfstiftung Hospital, Academic Teaching Hospital, Medical University Vienna, Vienna, Austria
| | - Martina Sanlorenzo
- Department of Dermatology, Mt. Zion Cancer Research Center, University of California San Francisco, San Francisco, California, USA; Department of Medical Sciences, Section of Dermatology, University of Turin, Turin, Italy
| | - Felix Weihsengruber
- Department of Dermatology, The Rudolfstiftung Hospital, Academic Teaching Hospital, Medical University Vienna, Vienna, Austria
| | - Klemens Rappersberger
- Department of Dermatology, The Rudolfstiftung Hospital, Academic Teaching Hospital, Medical University Vienna, Vienna, Austria
| | - Susana Ortiz-Urda
- Department of Dermatology, Mt. Zion Cancer Research Center, University of California San Francisco, San Francisco, California, USA
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12
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Yasuda T, Fukada T, Nishida K, Nakayama M, Matsuda M, Miura I, Dainichi T, Fukuda S, Kabashima K, Nakaoka S, Bin BH, Kubo M, Ohno H, Hasegawa T, Ohara O, Koseki H, Wakana S, Yoshida H. Hyperactivation of JAK1 tyrosine kinase induces stepwise, progressive pruritic dermatitis. J Clin Invest 2016; 126:2064-76. [PMID: 27111231 DOI: 10.1172/jci82887] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 03/03/2016] [Indexed: 01/12/2023] Open
Abstract
Skin homeostasis is maintained by the continuous proliferation and differentiation of epidermal cells. The skin forms a strong but flexible barrier against microorganisms as well as physical and chemical insults; however, the physiological mechanisms that maintain this barrier are not fully understood. Here, we have described a mutant mouse that spontaneously develops pruritic dermatitis as the result of an initial defect in skin homeostasis that is followed by induction of a Th2-biased immune response. These mice harbor a mutation that results in a single aa substitution in the JAK1 tyrosine kinase that results in hyperactivation, thereby leading to skin serine protease overexpression and disruption of skin barrier function. Accordingly, treatment with an ointment to maintain normal skin barrier function protected mutant mice from dermatitis onset. Pharmacological inhibition of JAK1 also delayed disease onset. Together, these findings indicate that JAK1-mediated signaling cascades in skin regulate the expression of proteases associated with the maintenance of skin barrier function and demonstrate that perturbation of these pathways can lead to the development of spontaneous pruritic dermatitis.
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13
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Testoni E, Stephenson NL, Torres-Ayuso P, Marusiak AA, Trotter EW, Hudson A, Hodgkinson CL, Morrow CJ, Dive C, Brognard J. Somatically mutated ABL1 is an actionable and essential NSCLC survival gene. EMBO Mol Med 2016; 8:105-16. [PMID: 26758680 PMCID: PMC4734836 DOI: 10.15252/emmm.201505456] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 11/25/2015] [Accepted: 12/08/2015] [Indexed: 01/22/2023] Open
Abstract
The lack of actionable mutations in patients with non-small cell lung cancer (NSCLC) presents a significant hurdle in the design of targeted therapies for this disease. Here, we identify somatically mutated ABL1 as a genetic dependency that is required to maintain NSCLC cell survival. We demonstrate that NSCLC cells with ABL1 mutations are sensitive to ABL inhibitors and we verify that the drug-induced effects on cell viability are specific to pharmacological inhibition of the ABL1 kinase. Furthermore, we confirm that imatinib suppresses lung tumor growth in vivo, specifically in lung cancer cells harboring a gain-of-function (GOF) mutation in ABL1. Consistent with structural modeling, we demonstrate that mutations in ABL1 identified in primary NSCLC tumors and a lung cancer cell line increase downstream pathway activation compared to wild-type ABL1. Finally, we observe that the ABL1 cancer mutants display an increased cytosolic localization, which is associated with the oncogenic properties of the ABL1 kinase. In summary, our results suggest that NSCLC patients with ABL1 mutations could be stratified for treatment with imatinib in combination with other therapies.
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Affiliation(s)
- Ewelina Testoni
- Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - Natalie L Stephenson
- Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - Pedro Torres-Ayuso
- Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - Anna A Marusiak
- Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - Eleanor W Trotter
- Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - Andrew Hudson
- Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - Cassandra L Hodgkinson
- Clinical and Experimental Pharmacology Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - Christopher J Morrow
- Clinical and Experimental Pharmacology Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - Caroline Dive
- Clinical and Experimental Pharmacology Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
| | - John Brognard
- Signalling Networks in Cancer Group, Cancer Research UK Manchester Institute The University of Manchester, Manchester, UK
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14
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Lowder MA, Doerner AE, Schepartz A. Structural Differences between Wild-Type and Double Mutant EGFR Modulated by Third-Generation Kinase Inhibitors. J Am Chem Soc 2015; 137:6456-9. [PMID: 25973741 PMCID: PMC4638123 DOI: 10.1021/jacs.5b02326] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mutations in the EGFR kinase domain are implicated in non-small-cell lung cancer. Of particular interest is the drug-resistant double mutant (L858R/T790M, DM EGFR), which is not inhibited selectively by any approved kinase inhibitor. Here we apply bipartite tetracysteine display to demonstrate that DM and WT EGFR differ in structure outside the kinase domain. The structural difference is located within the cytoplasmic juxtamembrane segment (JM) that links the kinase domain with the extracellular and transmembrane regions and is essential for EGFR activation. We show further that third-generation DM EGFR-selective TKIs alter JM structure via allostery to restore the conformation found when WT EGFR is activated by the growth factors EGF and HB-EGF. This work suggests that the oncogenic activity of DM EGFR may extend beyond kinase activity per se to include kinase-independent activities. As JM structure may provide a biomarker for these kinase-independent functions, these insights could guide the development of allosteric, DM-selective inhibitors.
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Affiliation(s)
- Melissa A. Lowder
- Department of Molecular Biophysics & Biochemistry, Yale University, 225 Prospect St., New Haven CT 06511
| | - Amy E. Doerner
- Department of Chemistry, Yale University, 225 Prospect St., New Haven CT 06511
| | - Alanna Schepartz
- Department of Chemistry, Yale University, 225 Prospect St., New Haven CT 06511
- Department of Molecular, Cellular, and Developmental Biology, Yale University, 225 Prospect St., New Haven CT 06511
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15
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Martinez JM, Wang HZ, Lin RZ, Brink PR, White TW. Differential regulation of Connexin50 and Connexin46 by PI3K signaling. FEBS Lett 2015; 589:1340-5. [PMID: 25935417 PMCID: PMC4433579 DOI: 10.1016/j.febslet.2015.04.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/06/2015] [Accepted: 04/16/2015] [Indexed: 01/28/2023]
Abstract
Gap junction channels can modify their activity in response to cell signaling pathways. Here, we demonstrate that Connexin50 (Cx50) coupling, but not Connexin46 (Cx46), increased when co-expressed with a constitutively active p110α subunit of PI3K in Xenopus oocytes. In addition, inhibition of PI3K signaling by blocking p110α, or Akt, significantly decreased gap junctional conductance in Cx50 transfected HeLa cells, with no effect on Cx46. Alterations in coupling levels were not a result of reduced Cx50 unitary conductance, suggesting that changes in the number of active channels were responsible. These data indicate that Cx50 is specifically regulated by the PI3K signaling pathway.
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Affiliation(s)
- Jennifer M Martinez
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Hong-Zhan Wang
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Richard Z Lin
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Peter R Brink
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Thomas W White
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA.
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16
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Chen YJ, Lai KC, Kuo HH, Chow LP, Yih LH, Lee TC. HSP70 colocalizes with PLK1 at the centrosome and disturbs spindle dynamics in cells arrested in mitosis by arsenic trioxide. Arch Toxicol 2014; 88:1711-23. [PMID: 24623308 DOI: 10.1007/s00204-014-1222-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 03/03/2014] [Indexed: 11/26/2022]
Abstract
Heat shock protein 70 (HSP70) has been shown to be a substrate of Polo-like kinase 1 (PLK1), and it prevents cells arrested in mitosis by arsenic trioxide (ATO) from dying. Here, we report that HSP70 participates in ATO-induced spindle elongation, which interferes with mitosis progression. Our results demonstrate that HSP70 and PLK1 colocalize at the centrosome in ATO-arrested mitotic cells. HSP70 located at the centrosome was found to be phosphorylated by PLK1 at Ser⁶³¹ and Ser⁶³³. Moreover, unlike wild-type HSP70 (HSP70(wt)) and its phosphomimetic mutant (HSP70(SS631,633DD)), a phosphorylation-resistant mutant of HSP70 (HSP70(SS631,633AA)) failed to localize at the centrosome. ATO-induced spindle elongation was abolished in cells overexpressing HSP70(SS631,633AA). Conversely, mitotic spindles in cells ectopically expressing HSP70(SS631,633DD) were more resistant to nocodazole-induced depolymerization than in those expressing HSP70(wt) or HSP70(SS631,633AA). In addition, inhibition of PLK1 significantly reduced HSP70 phosphorylation and induced early onset of apoptosis in ATO-arrested mitotic cells. Taken together, our results indicate that PLK1-mediated phosphorylation and centrosomal localization of HSP70 may interfere with spindle dynamics and prevent apoptosis of ATO-arrested mitotic cells.
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Affiliation(s)
- Yu-Ju Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan
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17
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Abstract
Melanocortin 4 receptor (MC4R) is a key factor in regulating energy homeostasis, and null mutations occurring in the gene encoding MC4R cause severe early-onset morbid obesity in humans. Many obesity-causing mutations affecting MC4R clinically identified so far lead to failure of mutant receptors to shuttle to the plasma membrane. In this study, we show that a novel human MC4R antagonist, Ipsen 17, acted as an pharmacological chaperone of human MCR4. As tested with 12 obesity-causing human MC4R variants including S58C, E61K, N62S, I69T, P78L, C84R, G98R, T162I, R165W, W174C, C271Y, and P299H, Ipsen 17 was found to be the most universal pharmacological chaperone of MC4R reported so far because it can completely rescue nearly all mutant receptors (except P299H) with the highest potency (an EC50 value of approximately 10(-8) M) and efficiency when compared with results for other tested pharmacological chaperones of MC4R including ML00253764, PBA, MTHP, PPPone, MPCI, DCPMP, and NBP described in the literature. Once restored to the plasma membrane, defective human MC4R variants responded to α-MSH stimulation with an EC50 value of approximately 10(-8) M and displayed dramatically enhanced signaling ability (except for G98R) in a mutant-specific efficacy and potency profile. Taken together, these results indicate that Ipsen 17 represents a candidate for the development of a targeted treatment of severe early-onset morbid obesity caused by a large subset of inherited mutations in the human MC4R gene.
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Affiliation(s)
- Xiao-Hua Wang
- Key Laboratory of Food Nutrition and Safety (Tianjin University of Science and Technology)College of Food Engineering and Biotechnology, Ministry of Education, No. 29 13rd Road, Tianjin Economy-and-Technology Development Area, Tianjin 300457, People's Republic of ChinaObesita and Algaegen LLCCollege Station, Texas 77845, USACollege of BiotechnologyTianjin University of Science and Technology, Tianjin 300457, People's Republic of China
| | - Hao-Meng Wang
- Key Laboratory of Food Nutrition and Safety (Tianjin University of Science and Technology)College of Food Engineering and Biotechnology, Ministry of Education, No. 29 13rd Road, Tianjin Economy-and-Technology Development Area, Tianjin 300457, People's Republic of ChinaObesita and Algaegen LLCCollege Station, Texas 77845, USACollege of BiotechnologyTianjin University of Science and Technology, Tianjin 300457, People's Republic of China
| | - Bao-Lei Zhao
- Key Laboratory of Food Nutrition and Safety (Tianjin University of Science and Technology)College of Food Engineering and Biotechnology, Ministry of Education, No. 29 13rd Road, Tianjin Economy-and-Technology Development Area, Tianjin 300457, People's Republic of ChinaObesita and Algaegen LLCCollege Station, Texas 77845, USACollege of BiotechnologyTianjin University of Science and Technology, Tianjin 300457, People's Republic of China
| | - Peng Yu
- Key Laboratory of Food Nutrition and Safety (Tianjin University of Science and Technology)College of Food Engineering and Biotechnology, Ministry of Education, No. 29 13rd Road, Tianjin Economy-and-Technology Development Area, Tianjin 300457, People's Republic of ChinaObesita and Algaegen LLCCollege Station, Texas 77845, USACollege of BiotechnologyTianjin University of Science and Technology, Tianjin 300457, People's Republic of China
| | - Zhen-Chuan Fan
- Key Laboratory of Food Nutrition and Safety (Tianjin University of Science and Technology)College of Food Engineering and Biotechnology, Ministry of Education, No. 29 13rd Road, Tianjin Economy-and-Technology Development Area, Tianjin 300457, People's Republic of ChinaObesita and Algaegen LLCCollege Station, Texas 77845, USACollege of BiotechnologyTianjin University of Science and Technology, Tianjin 300457, People's Republic of ChinaKey Laboratory of Food Nutrition and Safety (Tianjin University of Science and Technology)College of Food Engineering and Biotechnology, Ministry of Education, No. 29 13rd Road, Tianjin Economy-and-Technology Development Area, Tianjin 300457, People's Republic of ChinaObesita and Algaegen LLCCollege Station, Texas 77845, USACollege of BiotechnologyTianjin University of Science and Technology, Tianjin 300457, People's Republic of China
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18
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Xie X, Langlais P, Zhang X, Heckmann BL, Saarinen AM, Mandarino LJ, Liu J. Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization. Am J Physiol Endocrinol Metab 2014; 306:E1449-59. [PMID: 24801391 PMCID: PMC4059987 DOI: 10.1152/ajpendo.00663.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adipose triglyceride lipase (ATGL), the rate-limiting enzyme for triacylglycerol (TG) hydrolysis, has long been known to be a phosphoprotein. However, the potential phosphorylation events that are involved in the regulation of ATGL function remain incompletely defined. Here, using a combinatorial proteomics approach, we obtained evidence that at least eight different sites of ATGL can be phosphorylated in adipocytes. Among them, Thr³⁷² resides within the hydrophobic region known to mediate lipid droplet (LD) targeting. Although it had no impact on the TG hydrolase activity, substitution of phosphorylation-mimic Asp for Thr³⁷² eliminated LD localization and LD-degrading capacity of ATGL expressed in HeLa cells. In contrast, mutation of Thr³⁷² to Ala gave a protein that bound LDs and functioned the same as the wild-type protein. In nonstimulated adipocytes, the Asp mutation led to decreased LD association and basal lipolytic activity of ATGL, whereas the Ala mutation produced opposite effects. Moreover, the LD translocation of ATGL upon β-adrenergic stimulation was also compromised by the Asp mutation. In accord with these findings, the Ala mutation promoted and the Asp mutation attenuated the capacity of ATGL to mediate lipolysis in adipocytes under both basal and stimulated conditions. Collectively, these studies identified Thr³⁷² as a novel phosphorylation site that may play a critical role in determining subcellular distribution as well as lipolytic action of ATGL.
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Affiliation(s)
- Xitao Xie
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Scottsdale, Arizona; HEALth Program, Mayo Clinic, Scottsdale, Arizona
| | | | - Xiaodong Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Scottsdale, Arizona; HEALth Program, Mayo Clinic, Scottsdale, Arizona
| | - Bradlee L Heckmann
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Scottsdale, Arizona; HEALth Program, Mayo Clinic, Scottsdale, Arizona; Mayo Graduate School, Rochester, Minnesota; and
| | - Alicia M Saarinen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Scottsdale, Arizona; HEALth Program, Mayo Clinic, Scottsdale, Arizona
| | - Lawrence J Mandarino
- HEALth Program, Mayo Clinic, Scottsdale, Arizona; Division of Endocrinology, Mayo Clinic, Scottsdale, Arizona; Center for Metabolic and Vascular Biology, Arizona State University, Tempe, Arizona
| | - Jun Liu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Scottsdale, Arizona; HEALth Program, Mayo Clinic, Scottsdale, Arizona; Division of Endocrinology, Mayo Clinic, Scottsdale, Arizona;
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19
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Drouet V, Ruiz M, Zala D, Feyeux M, Auregan G, Cambon K, Troquier L, Carpentier J, Aubert S, Merienne N, Bourgois-Rocha F, Hassig R, Rey M, Dufour N, Saudou F, Perrier AL, Hantraye P, Déglon N. Allele-specific silencing of mutant huntingtin in rodent brain and human stem cells. PLoS One 2014; 9:e99341. [PMID: 24926995 PMCID: PMC4057216 DOI: 10.1371/journal.pone.0099341] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/14/2014] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder resulting from polyglutamine expansion in the huntingtin (HTT) protein and for which there is no cure. Although suppression of both wild type and mutant HTT expression by RNA interference is a promising therapeutic strategy, a selective silencing of mutant HTT represents the safest approach preserving WT HTT expression and functions. We developed small hairpin RNAs (shRNAs) targeting single nucleotide polymorphisms (SNP) present in the HTT gene to selectively target the disease HTT isoform. Most of these shRNAs silenced, efficiently and selectively, mutant HTT in vitro. Lentiviral-mediated infection with the shRNAs led to selective degradation of mutant HTT mRNA and prevented the apparition of neuropathology in HD rat's striatum expressing mutant HTT containing the various SNPs. In transgenic BACHD mice, the mutant HTT allele was also silenced by this approach, further demonstrating the potential for allele-specific silencing. Finally, the allele-specific silencing of mutant HTT in human embryonic stem cells was accompanied by functional recovery of the vesicular transport of BDNF along microtubules. These findings provide evidence of the therapeutic potential of allele-specific RNA interference for HD.
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Affiliation(s)
- Valérie Drouet
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
| | - Marta Ruiz
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
| | - Diana Zala
- Institut Curie, Orsay, France
- UMR3306, Centre National de Recherché Scientifique (CNRS), Orsay, France
- U1005, Institut National de la Santé et de la Recherche Médicale (INSERM), Orsay France
| | - Maxime Feyeux
- U861, Institut National de la Santé et de la Recherche Médicale (INSERM), AFM, Evry, France
- UEVE U861, I-STEM, AFM, Evry, France
| | - Gwennaëlle Auregan
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
| | - Karine Cambon
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
| | - Laetitia Troquier
- Department of Clinical Neurosciences (DNC), Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Johann Carpentier
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
| | | | - Nicolas Merienne
- Department of Clinical Neurosciences (DNC), Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Fany Bourgois-Rocha
- U861, Institut National de la Santé et de la Recherche Médicale (INSERM), AFM, Evry, France
- UEVE U861, I-STEM, AFM, Evry, France
| | - Raymonde Hassig
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
| | - Maria Rey
- Department of Clinical Neurosciences (DNC), Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Noëlle Dufour
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
| | - Frédéric Saudou
- Institut Curie, Orsay, France
- UMR3306, Centre National de Recherché Scientifique (CNRS), Orsay, France
- U1005, Institut National de la Santé et de la Recherche Médicale (INSERM), Orsay France
| | - Anselme L. Perrier
- U861, Institut National de la Santé et de la Recherche Médicale (INSERM), AFM, Evry, France
- UEVE U861, I-STEM, AFM, Evry, France
| | - Philippe Hantraye
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
| | - Nicole Déglon
- Institute of Biomedical Imaging (I2BM) and Molecular Imaging Research Center (MIRCen), Atomic Energy Commission (CEA), Fontenay-aux-Roses, France
- URA2210, Centre National de Recherché Scientifique (CNRS), Fontenay-aux-Roses, France
- Department of Clinical Neurosciences (DNC), Lausanne University Hospital (CHUV), Lausanne, Switzerland
- * E-mail:
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Stich N, Model N, Samstag A, Gruener CS, Wolf HM, Eibl MM. Toxic shock syndrome toxin-1-mediated toxicity inhibited by neutralizing antibodies late in the course of continual in vivo and in vitro exposure. Toxins (Basel) 2014; 6:1724-41. [PMID: 24887085 PMCID: PMC4073126 DOI: 10.3390/toxins6061724] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/07/2014] [Accepted: 05/20/2014] [Indexed: 02/05/2023] Open
Abstract
Toxic shock syndrome (TSS) results from the host's overwhelming inflammatory response and cytokine storm mainly due to superantigens (SAgs). There is no effective specific therapy. Application of immunoglobulins has been shown to improve the outcome of the disease and to neutralize SAgs both in vivo and in vitro. However, in most experiments that have been performed, antiserum was either pre-incubated with SAg, or both were applied simultaneously. To mirror more closely the clinical situation, we applied a multiple dose (over five days) lethal challenge in a rabbit model. Treatment with toxic shock syndrome toxin 1 (TSST-1) neutralizing antibody was fully protective, even when administered late in the course of the challenge. Kinetic studies on the effect of superantigen toxins are scarce. We performed in vitro kinetic studies by neutralizing the toxin with antibodies at well-defined time points. T-cell activation was determined by assessing T-cell proliferation (3H-thymidine incorporation), determination of IL-2 release in the cell supernatant (ELISA), and IL-2 gene activation (real-time PCR (RT-PCR)). Here we show that T-cell activation occurs continuously. The application of TSST-1 neutralizing antiserum reduced IL-2 and TNFα release into the cell supernatant, even if added at later time points. Interference with the prolonged stimulation of proinflammatory cytokines is likely to be in vivo relevant, as postexposure treatment protected rabbits against the multiple dose lethal SAg challenge. Our results shed new light on the treatment of TSS by specific antibodies even at late stages of exposure.
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MESH Headings
- Animals
- Antibodies, Neutralizing/pharmacology
- Antibodies, Neutralizing/therapeutic use
- Antitoxins/pharmacology
- Antitoxins/therapeutic use
- Bacterial Toxins/antagonists & inhibitors
- Bacterial Toxins/genetics
- Bacterial Toxins/metabolism
- Bacterial Toxins/toxicity
- Cell Proliferation/drug effects
- Cells, Cultured
- Disease Models, Animal
- Enterotoxins/antagonists & inhibitors
- Enterotoxins/genetics
- Enterotoxins/metabolism
- Enterotoxins/toxicity
- Female
- Gene Expression Regulation/drug effects
- Humans
- Interleukin-2/genetics
- Interleukin-2/metabolism
- Leukocytes, Mononuclear/cytology
- Leukocytes, Mononuclear/drug effects
- Leukocytes, Mononuclear/immunology
- Leukocytes, Mononuclear/metabolism
- Lymphocyte Activation/drug effects
- Male
- Mutant Proteins/antagonists & inhibitors
- Mutant Proteins/metabolism
- Mutant Proteins/toxicity
- Rabbits
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Recombinant Proteins/toxicity
- Shock, Septic/drug therapy
- Shock, Septic/etiology
- Shock, Septic/immunology
- Shock, Septic/metabolism
- Superantigens/genetics
- Superantigens/metabolism
- Superantigens/toxicity
- Survival Analysis
- T-Lymphocytes/drug effects
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Toxicokinetics
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Norbert Stich
- Biomedizinische ForschungsgmbH Lazarettgasse 19/2, Vienna A-1090, Austria.
| | - Nina Model
- Biomedizinische ForschungsgmbH Lazarettgasse 19/2, Vienna A-1090, Austria.
| | - Aysen Samstag
- Immunology Outpatient Clinic, Schwarzspanierstrasse 15, Vienna A-1090, Austria.
| | - Corina S Gruener
- Biomedizinische ForschungsgmbH Lazarettgasse 19/2, Vienna A-1090, Austria.
| | - Hermann M Wolf
- Immunology Outpatient Clinic, Schwarzspanierstrasse 15, Vienna A-1090, Austria.
| | - Martha M Eibl
- Biomedizinische ForschungsgmbH Lazarettgasse 19/2, Vienna A-1090, Austria.
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21
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Masuyer G, Akif M, Czarny B, Beau F, Schwager SLU, Sturrock ED, Isaac RE, Dive V, Acharya KR. Crystal structures of highly specific phosphinic tripeptide enantiomers in complex with the angiotensin-I converting enzyme. FEBS J 2014; 281:943-56. [PMID: 24289879 PMCID: PMC4154125 DOI: 10.1111/febs.12660] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/22/2013] [Accepted: 11/25/2013] [Indexed: 11/27/2022]
Abstract
Human somatic angiotensin-I converting enzyme (ACE) is a zinc-dependent dipeptidyl carboxypeptidase and a central component of the renin angiotensin aldosterone system (RAAS). Its involvement in the modulation of physiological actions of peptide hormones has positioned ACE as an important therapeutic target for the treatment of hypertension and cardiovascular disorders. Here, we report the crystal structures of the two catalytic domains of human ACE (N- and C-) in complex with FI, the S enantiomer of the phosphinic ACE/ECE-1 (endothelin converting enzyme) dual inhibitor FII, to a resolution of 1.91 and 1.85 Å, respectively. In addition, we have determined the structure of AnCE (an ACE homologue from Drosophila melanogaster) in complex with both isomers. The inhibitor FI (S configuration) can adapt to the active site of ACE catalytic domains and shows key differences in its binding mechanism mostly through the reorientation of the isoxazole phenyl side group at the P₁' position compared with FII (R configuration). Differences in binding are also observed between FI and FII in complex with AnCE. Thus, the new structures of the ACE-inhibitor complexes presented here provide useful information for further exploration of ACE inhibitor pharmacophores involving phosphinic peptides and illustrate the role of chirality in enhancing drug specificity.
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Affiliation(s)
| | - Mohd Akif
- Department of Biology and BiochemistryUniversity of BathUK
- Department of BiochemistryUniversity of HyderabadIndia
| | - Bertrand Czarny
- Service d'Ingénierie Moléculaire des ProtéinesCEAiBiTecSGif‐sur‐YvetteFrance
| | - Fabrice Beau
- Service d'Ingénierie Moléculaire des ProtéinesCEAiBiTecSGif‐sur‐YvetteFrance
| | - Sylva L. U. Schwager
- Division of Medical BiochemistryInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownSouth Africa
| | - Edward D. Sturrock
- Division of Medical BiochemistryInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownSouth Africa
| | | | - Vincent Dive
- Service d'Ingénierie Moléculaire des ProtéinesCEAiBiTecSGif‐sur‐YvetteFrance
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22
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Luis BS, Carpino N. Insights into the suppressor of T-cell receptor (TCR) signaling-1 (Sts-1)-mediated regulation of TCR signaling through the use of novel substrate-trapping Sts-1 phosphatase variants. FEBS J 2014; 281:696-707. [PMID: 24256567 PMCID: PMC3968691 DOI: 10.1111/febs.12615] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 10/09/2013] [Accepted: 11/05/2013] [Indexed: 01/04/2023]
Abstract
High affinity substrate-trapping protein tyrosine phosphatases have been widely used both to investigate the endogenous targets of many phosphatases and to address questions of substrate specificity. Herein, we extend the concept of a substrate-trapping phosphatase to include an enzyme of the histidine phosphatase superfamily. This is the first description of substrate-trapping technology applied to a member of the histidine phosphatase family. The phosphatase suppressor of T-cell receptor signaling (Sts)-1 has recently been reported to negatively regulate signaling downstream of the T-cell receptor. We generated high-affinity substrate-trapping variants of Sts-1 by mutagenesis of key active site residues within the phosphatase catalytic domain. Mutation of both the nucleophilic His380 and the general acid Glu490 yielded Sts-1 enzymes that were catalytically inactive but showed high affinity for an important tyrosine kinase in T cells that Sts-1 is known to regulate, Zap-70. Sts-1 substrate-trapping mutants isolated tyrosine-phosphorylated Zap-70 from lysates of activated T cells, validating Zap-70 as a possible substrate for Sts-1 and highlighting the efficacy of the mutants as substrate-trapping agents. Inhibition of the Zap-70 interaction by vanadate suggests that the substrate-trapping effect occurred via the Sts-1 phosphatase active site. Finally, overexpression of Sts-1 substrate-trapping mutants in T cells blocked T-cell receptor signaling, confirming the inhibitory effect of Sts-1 on Zap-70.
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Affiliation(s)
- Boris S Luis
- Program in Molecular and Cellular Biology, Stony Brook University, NY, USA
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23
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24
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Abstract
Cytochrome c oxidase from bovine heart binds Ca2+ reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca2+ shifts the absorption spectrum of heme a, which allowed previously to determine the kinetics and equilibrium characteristics of the binding. However, no effect of Ca2+ on the functional characteristics of cytochrome oxidase was revealed earlier. Here we report that Ca2+ inhibits cytochrome oxidase activity of isolated bovine heart enzyme by 50–60% with Ki of ∼1 µM, close to Kd of calcium binding with the oxidase determined spectrophotometrically. The inhibition is observed only at low, but physiologically relevant, turnover rates of the enzyme (∼10 s−1 or less). No inhibitory effect of Ca2+ is observed under conventional conditions of cytochrome c oxidase activity assays (turnover number >100 s−1 at pH 8), which may explain why the effect was not noticed earlier. The inhibition is specific for Ca2+ and is reversed by EGTA. Na+ ions that compete with Ca2+ for binding with the Cation Binding Site, do not affect significantly activity of the enzyme but counteract the inhibitory effect of Ca2+. The Ca2+-induced inhibition of cytochrome c oxidase is observed also with the uncoupled mitochondria from several rat tissues. At the same time, calcium ions do not inhibit activity of the homologous bacterial cytochrome oxidases. Possible mechanisms of the inhibition are discussed as well as potential physiological role of Ca2+ binding with cytochrome oxidase. Ca2+- binding at the Cation Binding Site is proposed to inhibit proton-transfer through the exit part of the proton conducting pathway H in the mammalian oxidases.
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Affiliation(s)
- Tatiana Vygodina
- A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
| | - Anna Kirichenko
- A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
| | - Alexander A. Konstantinov
- A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
- * E-mail:
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25
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Mologni L, Redaelli S, Morandi A, Plaza-Menacho I, Gambacorti-Passerini C. Ponatinib is a potent inhibitor of wild-type and drug-resistant gatekeeper mutant RET kinase. Mol Cell Endocrinol 2013; 377:1-6. [PMID: 23811235 DOI: 10.1016/j.mce.2013.06.025] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/11/2013] [Accepted: 06/17/2013] [Indexed: 01/03/2023]
Abstract
RET kinase is aberrantly activated in thyroid cancers and in rare cases of lung and colon cancer, and has been validated as a molecular target in these tumors. Vandetanib was recently approved for the treatment of medullary thyroid cancer. However, vandetanib is ineffective in vitro against RET mutants carrying bulky aminoacids at position 804, the gatekeeper residue, similarly to drug-resistant BCR-ABL mutants in chronic myeloid leukemia. Ponatinib is a multi-target kinase inhibitor that was recently approved for treatment-refractory Philadelphia-positive leukemia. We show here potent inhibition of oncogenic RET by ponatinib, including the drug-insensitive V804M/L mutants. Ponatinib inhibited the growth of RET+ and BCR-ABL+ cells with similar potency, while not affecting RET-negative cells. Both in biochemical and in cellular assays ponatinib compared favorably with known RET inhibitors, such as vandetanib, cabozantinib, sorafenib, sunitinib and motesanib, used as reference compounds. We suggest that ponatinib should be considered for the treatment of RET+ tumors, in particular those expressing vandetanib-resistant V804M/L mutations.
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Affiliation(s)
- Luca Mologni
- Dept. of Health Sciences, University of Milano-Bicocca, via Cadore 48, 20900 Monza, Italy.
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26
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Hamson DK, Wainwright SR, Taylor JR, Jones BA, Watson NV, Galea LAM. Androgens increase survival of adult-born neurons in the dentate gyrus by an androgen receptor-dependent mechanism in male rats. Endocrinology 2013; 154:3294-304. [PMID: 23782943 DOI: 10.1210/en.2013-1129] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Gonadal steroids are potent regulators of adult neurogenesis. We previously reported that androgens, such as testosterone (T) and dihydrotestosterone (DHT), but not estradiol, increased the survival of new neurons in the dentate gyrus of the male rat. These results suggest androgens regulate hippocampal neurogenesis via the androgen receptor (AR). To test this supposition, we examined the role of ARs in hippocampal neurogenesis using 2 different approaches. In experiment 1, we examined neurogenesis in male rats insensitive to androgens due to a naturally occurring mutation in the gene encoding the AR (termed testicular feminization mutation) compared with wild-type males. In experiment 2, we injected the AR antagonist, flutamide, into castrated male rats and compared neurogenesis levels in the dentate gyrus of DHT and oil-treated controls. In experiment 1, chronic T increased hippocampal neurogenesis in wild-type males but not in androgen-insensitive testicular feminization mutation males. In experiment 2, DHT increased hippocampal neurogenesis via cell survival, an effect that was blocked by concurrent treatment with flutamide. DHT, however, did not affect cell proliferation. Interestingly, cells expressing doublecortin, a marker of immature neurons, did not colabel with ARs in the dentate gyrus, but ARs were robustly expressed in other regions of the hippocampus. Together these studies provide complementary evidence that androgens regulate adult neurogenesis in the hippocampus via the AR but at a site other than the dentate gyrus. Understanding where in the brain androgens act to increase the survival of new neurons in the adult brain may have implications for neurodegenerative disorders.
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Affiliation(s)
- D K Hamson
- Department of Psychology, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
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27
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Tahiri A, Røe K, Ree AH, de Wijn R, Risberg K, Busch C, Lønning PE, Kristensen V, Geisler J. Differential inhibition of ex-vivo tumor kinase activity by vemurafenib in BRAF(V600E) and BRAF wild-type metastatic malignant melanoma. PLoS One 2013; 8:e72692. [PMID: 24023633 PMCID: PMC3758344 DOI: 10.1371/journal.pone.0072692] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 07/12/2013] [Indexed: 01/03/2023] Open
Abstract
Background Treatment of metastatic malignant melanoma patients harboring BRAF(V600E) has improved drastically after the discovery of the BRAF inhibitor, vemurafenib. However, drug resistance is a recurring problem, and prognoses are still very bad for patients harboring BRAF wild-type. Better markers for targeted therapy are therefore urgently needed. Methodology In this study, we assessed the individual kinase activity profiles in 26 tumor samples obtained from patients with metastatic malignant melanoma using peptide arrays with 144 kinase substrates. In addition, we studied the overall ex-vivo inhibitory effects of vemurafenib and sunitinib on kinase activity status. Results Overall kinase activity was significantly higher in lysates from melanoma tumors compared to normal skin tissue. Furthermore, ex-vivo incubation with both vemurafenib and sunitinib caused significant decrease in phosphorylation of kinase substrates, i.e kinase activity. While basal phosphorylation profiles were similar in BRAF wild-type and BRAF(V600E) tumors, analysis with ex-vivo vemurafenib treatment identified a subset of 40 kinase substrates showing stronger inhibition in BRAF(V600E) tumor lysates, distinguishing the BRAF wild-type and BRAF(V600E) tumors. Interestingly, a few BRAF wild-type tumors showed inhibition profiles similar to BRAF(V600E) tumors. The kinase inhibitory effect of vemurafenib was subsequently analyzed in cell lines harboring different BRAF mutational status with various vemurafenib sensitivity in-vitro. Conclusions Our findings suggest that multiplex kinase substrate array analysis give valuable information about overall tumor kinase activity. Furthermore, intra-assay exposure to kinase inhibiting drugs may provide a useful tool to study mechanisms of resistance, as well as to identify predictive markers.
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Affiliation(s)
- Andliena Tahiri
- Department of Clinical Molecular Biology and Laboratory Sciences, Akershus University Hospital, Lørenskog, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Kathrine Røe
- Department of Clinical Molecular Biology and Laboratory Sciences, Akershus University Hospital, Lørenskog, Norway
- Department of Oncology, Akershus University Hospital, Lørenskog, Norway
| | - Anne H. Ree
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Oncology, Akershus University Hospital, Lørenskog, Norway
| | - Rik de Wijn
- PamGene International B.V., ‘s- Hertogenbosch, The Netherlands
| | - Karianne Risberg
- Department of Oncology, Akershus University Hospital, Lørenskog, Norway
| | - Christian Busch
- Section of Oncology, Institute of Medicine, University of Bergen, Bergen, Norway
| | - Per E. Lønning
- Section of Oncology, Institute of Medicine, University of Bergen, Bergen, Norway
- Department of Oncology, Haukeland University Hospital, Bergen, Norway
| | - Vessela Kristensen
- Department of Clinical Molecular Biology and Laboratory Sciences, Akershus University Hospital, Lørenskog, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Jürgen Geisler
- Department of Clinical Molecular Biology and Laboratory Sciences, Akershus University Hospital, Lørenskog, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Oncology, Akershus University Hospital, Lørenskog, Norway
- * E-mail:
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28
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Ilangovan A, Fletcher M, Rampioni G, Pustelny C, Rumbaugh K, Heeb S, Cámara M, Truman A, Chhabra SR, Emsley J, Williams P. Structural basis for native agonist and synthetic inhibitor recognition by the Pseudomonas aeruginosa quorum sensing regulator PqsR (MvfR). PLoS Pathog 2013; 9:e1003508. [PMID: 23935486 PMCID: PMC3723537 DOI: 10.1371/journal.ppat.1003508] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 06/05/2013] [Indexed: 12/02/2022] Open
Abstract
Bacterial populations co-ordinate gene expression collectively through quorum sensing (QS), a cell-to-cell communication mechanism employing diffusible signal molecules. The LysR-type transcriptional regulator (LTTR) protein PqsR (MvfR) is a key component of alkyl-quinolone (AQ)-dependent QS in Pseudomonas aeruginosa. PqsR is activated by 2-alkyl-4-quinolones including the Pseudomonas quinolone signal (PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone), its precursor 2-heptyl-4-hydroxyquinoline (HHQ) and their C9 congeners, 2-nonyl-3-hydroxy-4(1H)-quinolone (C9-PQS) and 2-nonyl-4-hydroxyquinoline (NHQ). These drive the autoinduction of AQ biosynthesis and the up-regulation of key virulence determinants as a function of bacterial population density. Consequently, PqsR constitutes a potential target for novel antibacterial agents which attenuate infection through the blockade of virulence. Here we present the crystal structures of the PqsR co-inducer binding domain (CBD) and a complex with the native agonist NHQ. We show that the structure of the PqsR CBD has an unusually large ligand-binding pocket in which a native AQ agonist is stabilized entirely by hydrophobic interactions. Through a ligand-based design strategy we synthesized and evaluated a series of 50 AQ and novel quinazolinone (QZN) analogues and measured the impact on AQ biosynthesis, virulence gene expression and biofilm development. The simple exchange of two isosteres (OH for NH2) switches a QZN agonist to an antagonist with a concomitant impact on the induction of bacterial virulence factor production. We also determined the complex crystal structure of a QZN antagonist bound to PqsR revealing a similar orientation in the ligand binding pocket to the native agonist NHQ. This structure represents the first description of an LTTR-antagonist complex. Overall these studies present novel insights into LTTR ligand binding and ligand-based drug design and provide a chemical scaffold for further anti-P. aeruginosa virulence drug development by targeting the AQ receptor PqsR. Populations of bacterial cells collectively co-ordinate their activities through cell-to-cell communication via the production and sensing of signal molecules. This is called quorum sensing (QS) and in many bacteria, QS controls the expression of virulence genes, the products of which damage host tissues. Consequently, QS systems are potential targets for antimicrobial agents which do not kill bacteria but instead block their ability to cause disease. Pseudomonas aeruginosa causes a wide range of human infections and produces an armoury of virulence factors. Since many of these are controlled by alkylquinolone (AQ)-dependent QS, we determined the crystal structure of the AQ receptor (PqsR) in order to visualize the shape of the AQ-binding site and better design PqsR inhibitors which compete for the AQ binding site and so block QS. This work in conjunction with the chemical synthesis of AQ analogues resulted in the discovery of potent quinazolinone inhibitors of PqsR. These blocked AQ and virulence factor production in P. aeruginosa as well as biofilm development. Our studies present novel insights into the structure of PqsR and create further opportunities for target-based antibacterial drug development.
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Affiliation(s)
- Aravindan Ilangovan
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Pharmacy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Matthew Fletcher
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Giordano Rampioni
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Christian Pustelny
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Kendra Rumbaugh
- Department of Surgery, University of Texas, Lubbock, Texas, United States of America
| | - Stephan Heeb
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Miguel Cámara
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Alex Truman
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Siri Ram Chhabra
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Jonas Emsley
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Pharmacy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Paul Williams
- Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- School of Molecular Medical Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- * E-mail:
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29
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Sun J, Singh V, Lau A, Stokes RW, Obregón-Henao A, Orme IM, Wong D, Av-Gay Y, Hmama Z. Mycobacterium tuberculosis nucleoside diphosphate kinase inactivates small GTPases leading to evasion of innate immunity. PLoS Pathog 2013; 9:e1003499. [PMID: 23874203 PMCID: PMC3715411 DOI: 10.1371/journal.ppat.1003499] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 05/30/2013] [Indexed: 11/18/2022] Open
Abstract
Defining the mechanisms of Mycobacterium tuberculosis (Mtb) persistence in the host macrophage and identifying mycobacterial factors responsible for it are keys to better understand tuberculosis pathogenesis. The emerging picture from ongoing studies of macrophage deactivation by Mtb suggests that ingested bacilli secrete various virulence determinants that alter phagosome biogenesis, leading to arrest of Mtb vacuole interaction with late endosomes and lysosomes. While most studies focused on Mtb interference with various regulators of the endosomal compartment, little attention was paid to mechanisms by which Mtb neutralizes early macrophage responses such as the NADPH oxidase (NOX2) dependent oxidative burst. Here we applied an antisense strategy to knock down Mtb nucleoside diphosphate kinase (Ndk) and obtained a stable mutant (Mtb Ndk-AS) that displayed attenuated intracellular survival along with reduced persistence in the lungs of infected mice. At the molecular level, pull-down experiments showed that Ndk binds to and inactivates the small GTPase Rac1 in the macrophage. This resulted in the exclusion of the Rac1 binding partner p67phox from phagosomes containing Mtb or Ndk-coated latex beads. Exclusion of p67phox was associated with a defect of both NOX2 assembly and production of reactive oxygen species (ROS) in response to wild type Mtb. In contrast, Mtb Ndk-AS, which lost the capacity to disrupt Rac1-p67phox interaction, induced a strong ROS production. Given the established link between NOX2 activation and apoptosis, the proportion of Annexin V positive cells and levels of intracellular active caspase 3 were significantly higher in cells infected with Mtb Ndk-AS compared to wild type Mtb. Thus, knock down of Ndk converted Mtb into a pro-apoptotic mutant strain that has a phenotype of increased susceptibility to intracellular killing and reduced virulence in vivo. Taken together, our in vitro and in vivo data revealed that Ndk contributes significantly to Mtb virulence via attenuation of NADPH oxidase-mediated host innate immunity. Mycobacterium tuberculosis (Mtb) is a very successful intracellular pathogen that infects lung macrophages. Its resistance to intracellular killing has been linked to the development of pulmonary tuberculosis (TB) in humans. Thus, understanding the mechanism by which Mycobacterium tuberculosis (Mtb) persists in the host is a prerequisite for development of efficient strategies to control TB disease. We have previously shown that Mtb nucleoside diphosphate kinase (Ndk) contributes to phagosome maturation arrest via inactivation of Rab5 and Rab7. In this study, we show that Ndk also targets and inactivates the small GTPase Rac1, an essential component of the macrophage NADPH oxidase (NOX2) complex. Ndk-dependent inactivation of Rac1 was associated with reduced NOX2-mediated production of reactive oxygen species (ROS) and ROS-dependent apoptosis. Conversely, disruption of Ndk expression converted Mtb into a mutant strain that induces strong ROS and apoptosis responses. This phenotype was associated with reduced survival of Ndk mutant in vitro and in vivo. Altogether, our findings demonstrate that Ndk contributes significantly to mycobacterial virulence.
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MESH Headings
- Animals
- Bacterial Proteins/antagonists & inhibitors
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Bone Marrow Cells/cytology
- Bone Marrow Cells/enzymology
- Bone Marrow Cells/immunology
- Bone Marrow Cells/microbiology
- Cell Line, Transformed
- Cells, Cultured
- Female
- Humans
- Immunity, Innate
- Macrophages/enzymology
- Macrophages/immunology
- Macrophages/microbiology
- Macrophages/ultrastructure
- Mice
- Mice, Inbred C57BL
- Mice, SCID
- Mutant Proteins/antagonists & inhibitors
- Mutant Proteins/genetics
- Mutant Proteins/metabolism
- Mycobacterium tuberculosis/enzymology
- Mycobacterium tuberculosis/immunology
- Mycobacterium tuberculosis/pathogenicity
- Mycobacterium tuberculosis/physiology
- NADPH Oxidases/antagonists & inhibitors
- NADPH Oxidases/metabolism
- Neuropeptides/antagonists & inhibitors
- Neuropeptides/genetics
- Neuropeptides/metabolism
- Nucleoside-Diphosphate Kinase/antagonists & inhibitors
- Nucleoside-Diphosphate Kinase/genetics
- Nucleoside-Diphosphate Kinase/metabolism
- Oligoribonucleotides, Antisense
- Phagosomes/enzymology
- Phagosomes/ultrastructure
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Tuberculosis, Pulmonary/enzymology
- Tuberculosis, Pulmonary/immunology
- Tuberculosis, Pulmonary/microbiology
- Tuberculosis, Pulmonary/pathology
- Virulence
- rac1 GTP-Binding Protein/antagonists & inhibitors
- rac1 GTP-Binding Protein/genetics
- rac1 GTP-Binding Protein/metabolism
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Affiliation(s)
- Jim Sun
- Division of Infectious Diseases, Department of Medicine and Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vijender Singh
- Division of Infectious Diseases, Department of Medicine and Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alice Lau
- Division of Infectious Diseases, Department of Medicine and Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Richard W. Stokes
- Life Sciences Centre, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrés Obregón-Henao
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Ian M. Orme
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Dennis Wong
- Division of Infectious Diseases, Department of Medicine and Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yossef Av-Gay
- Division of Infectious Diseases, Department of Medicine and Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zakaria Hmama
- Division of Infectious Diseases, Department of Medicine and Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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30
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Dutta D, Chakraborty S, Bandyopadhyay C, Valiya Veettil M, Ansari MA, Singh VV, Chandran B. EphrinA2 regulates clathrin mediated KSHV endocytosis in fibroblast cells by coordinating integrin-associated signaling and c-Cbl directed polyubiquitination. PLoS Pathog 2013; 9:e1003510. [PMID: 23874206 PMCID: PMC3715429 DOI: 10.1371/journal.ppat.1003510] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 06/06/2013] [Indexed: 12/22/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) interacts with human dermal endothelial cell surface tyrosine kinase EphrinA2 (EphA2) and integrins (α3β1 and αVβ3) in the lipid raft (LR) region, and EphA2 regulates macropinocytic virus entry by coordinating integrin-c-Cbl associated signaling. In contrast, KSHV enters human foreskin fibroblast (HFF) cells by LR-independent clathrin mediated endocytosis. The present studies conducted to identify the key molecules regulating KSHV entry in HFF cells showed that KSHV induces association with integrins (αVβ5, αVβ3 and α3β1) and EphA2 in non-LR regions early during infection and activates EphA2, which in turn associates with phosphorylated c-Cbl, myosin IIA, FAK, Src, and PI3-K, as well as clathrin and its adaptor AP2 and effector Epsin-15 proteins. EphA2 knockdown significantly reduced these signal inductions, virus internalization and gene expression. c-Cbl knockdown ablated the c-Cbl mediated K63 type polyubiquitination of EphA2 and clathrin association with EphA2 and KSHV. Mutations in EphA2's tyrosine kinase domain (TKD) or sterile alpha motif (SAM) abolished its interaction with c-Cbl. Mutations in tyrosine kinase binding (TKB) or RING finger (RF) domains of c-Cbl resulted in very poor association of c-Cbl with EphA2 and decreased EphA2 polyubiquitination. These studies demonstrated the contributions of these domains in EphA2 and c-Cbl association, EphA2 polyubiquitination and virus-EphA2 internalization. Collectively, these results revealed for the first time that EphA2 influences the tyrosine phosphorylation of clathrin, the role of EphA2 in clathrin mediated endocytosis of a virus, and c-Cbl mediated EphA2 polyubiquitination directing KSHV entry in HFF cells via coordinated signal induction and progression of endocytic events, all of which suggest that targeting EphA2 and c-Cbl could block KSHV entry and infection.
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Affiliation(s)
- Dipanjan Dutta
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Sayan Chakraborty
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Chirosree Bandyopadhyay
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Mohanan Valiya Veettil
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Mairaj Ahmed Ansari
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Vivek Vikram Singh
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Bala Chandran
- H. M. Bligh Cancer Research Laboratories, Department of Microbiology and Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
- * E-mail:
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31
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Serra-Moreno R, Zimmermann K, Stern LJ, Evans DT. Tetherin/BST-2 antagonism by Nef depends on a direct physical interaction between Nef and tetherin, and on clathrin-mediated endocytosis. PLoS Pathog 2013; 9:e1003487. [PMID: 23853598 PMCID: PMC3708871 DOI: 10.1371/journal.ppat.1003487] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 05/28/2013] [Indexed: 11/30/2022] Open
Abstract
Nef is the viral gene product employed by the majority of primate lentiviruses to overcome restriction by tetherin (BST-2 or CD317), an interferon-inducible transmembrane protein that inhibits the detachment of enveloped viruses from infected cells. Although the mechanisms of tetherin antagonism by HIV-1 Vpu and HIV-2 Env have been investigated in detail, comparatively little is known about tetherin antagonism by SIV Nef. Here we demonstrate a direct physical interaction between SIV Nef and rhesus macaque tetherin, define the residues in Nef required for tetherin antagonism, and show that the anti-tetherin activity of Nef is dependent on clathrin-mediated endocytosis. SIV Nef co-immunoprecipitated with rhesus macaque tetherin and the Nef core domain bound directly to a peptide corresponding to the cytoplasmic domain of rhesus tetherin by surface plasmon resonance. An analysis of alanine-scanning substitutions identified residues throughout the N-terminal, globular core and flexible loop regions of Nef that were required for tetherin antagonism. Although there was significant overlap with sequences required for CD4 downregulation, tetherin antagonism was genetically separable from this activity, as well as from other Nef functions, including MHC class I-downregulation and infectivity enhancement. Consistent with a role for clathrin and dynamin 2 in the endocytosis of tetherin, dominant-negative mutants of AP180 and dynamin 2 impaired the ability of Nef to downmodulate tetherin and to counteract restriction. Taken together, these results reveal that the mechanism of tetherin antagonism by Nef depends on a physical interaction between Nef and tetherin, requires sequences throughout Nef, but is genetically separable from other Nef functions, and leads to the removal of tetherin from sites of virus release at the plasma membrane by clathrin-mediated endocytosis. Tetherin (BST-2, CD317 or HM1.24) is an interferon-inducible cellular restriction factor that prevents the release of enveloped viruses from infected cells. Human and simian immunodeficiency viruses have evolved to use different viral proteins to overcome the anti-viral effects of tetherin. Whereas HIV-1 Vpu and HIV-2 Env counteract human tetherin, most SIVs use the accessory protein Nef to counteract tetherin in their non-human primate hosts. Here we show that the mechanism of tetherin antagonism by SIV Nef involves a direct physical interaction between the core domain of Nef and the cytoplasmic domain of tetherin, which results in the removal of tetherin from sites of virus assembly and release on the cell surface by a mechanism that depends on clathrin and dynamin 2. The Nef-mediated internalization of tetherin leads to the accumulation of tetherin within lysosomal compartments, suggesting that, similar to CD4− and MHC I-downregulation, Nef promotes the lysosomal degradation of tetherin.
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Affiliation(s)
- Ruth Serra-Moreno
- Division of Microbiology, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America
- * E-mail: (RSM); (DTE)
| | - Kerstin Zimmermann
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Lawrence J. Stern
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - David T. Evans
- Division of Microbiology, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America
- * E-mail: (RSM); (DTE)
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32
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Abstract
Small ubiquitin-like modifier (SUMO1-3) is a small group of proteins that are ligated to lysine residues in target proteins. SUMO conjugation is a highly dynamic process, as SUMOylated proteins are rapidly deconjugated by SUMO proteases. SUMO conjugation/deconjugation plays pivotal roles in major cellular pathways and is associated with a number of pathological conditions. It is therefore of significant clinical interest to develop new strategies to screen for compounds to specifically interfere with SUMO conjugation/deconjugation. Here, we describe a novel high-throughput screening (HTS)-compatible assay to identify inhibitors of SUMO proteases. The assay is based on AlphaScreen technology and uses His-tagged SUMO2 conjugated to Strep-tagged SUMO3 as a SUMO protease substrate. A bacterial SUMOylation system was used to generate this substrate. A three-step purification strategy was employed to yield substrate of high quality. Our data indicated that this unique substrate can be readily detected in the AlphaScreen assays in a dose-dependent manner. Cleavage reactions by SUMO protease with or without inhibitor were monitored based on AlphaScreen signals. Furthermore, the assay was adapted to a 384-well format, and the interplate and interday variability was evaluated in eight 384-well plates. The average Z' factor was 0.83 ± 0.04, confirming the suitability for HTS applications.
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Affiliation(s)
- Wei Yang
- Multidisciplinary Neuroprotection Laboratories, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA.
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33
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Rohle D, Popovici-Muller J, Palaskas N, Turcan S, Grommes C, Campos C, Tsoi J, Clark O, Oldrini B, Komisopoulou E, Kunii K, Pedraza A, Schalm S, Silverman L, Miller A, Wang F, Yang H, Chen Y, Kernytsky A, Rosenblum MK, Liu W, Biller SA, Su SM, Brennan CW, Chan TA, Graeber TG, Yen KE, Mellinghoff IK. An inhibitor of mutant IDH1 delays growth and promotes differentiation of glioma cells. Science 2013; 340:626-30. [PMID: 23558169 PMCID: PMC3985613 DOI: 10.1126/science.1236062] [Citation(s) in RCA: 867] [Impact Index Per Article: 78.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The recent discovery of mutations in metabolic enzymes has rekindled interest in harnessing the altered metabolism of cancer cells for cancer therapy. One potential drug target is isocitrate dehydrogenase 1 (IDH1), which is mutated in multiple human cancers. Here, we examine the role of mutant IDH1 in fully transformed cells with endogenous IDH1 mutations. A selective R132H-IDH1 inhibitor (AGI-5198) identified through a high-throughput screen blocked, in a dose-dependent manner, the ability of the mutant enzyme (mIDH1) to produce R-2-hydroxyglutarate (R-2HG). Under conditions of near-complete R-2HG inhibition, the mIDH1 inhibitor induced demethylation of histone H3K9me3 and expression of genes associated with gliogenic differentiation. Blockade of mIDH1 impaired the growth of IDH1-mutant--but not IDH1-wild-type--glioma cells without appreciable changes in genome-wide DNA methylation. These data suggest that mIDH1 may promote glioma growth through mechanisms beyond its well-characterized epigenetic effects.
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Affiliation(s)
- Dan Rohle
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Department of Pharmacology, Weill-Cornell Graduate School of Biomedical Sciences, New York, NY 10021, USA
| | | | - Nicolaos Palaskas
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Sevin Turcan
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Christian Grommes
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Carl Campos
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Jennifer Tsoi
- Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, University of California, Los Angeles, CA 90095, USA
| | - Owen Clark
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Barbara Oldrini
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Evangelia Komisopoulou
- Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, University of California, Los Angeles, CA 90095, USA
| | - Kaiko Kunii
- Agios Pharmaceuticals, Cambridge, MA 02139, USA
| | - Alicia Pedraza
- Department of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | | | | | - Alexandra Miller
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Fang Wang
- Agios Pharmaceuticals, Cambridge, MA 02139, USA
| | - Hua Yang
- Agios Pharmaceuticals, Cambridge, MA 02139, USA
| | - Yue Chen
- Agios Pharmaceuticals, Cambridge, MA 02139, USA
| | | | - Marc K. Rosenblum
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Wei Liu
- Agios Pharmaceuticals, Cambridge, MA 02139, USA
| | | | | | - Cameron W. Brennan
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Department of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Timothy A. Chan
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Thomas G. Graeber
- Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, University of California, Los Angeles, CA 90095, USA
| | | | - Ingo K. Mellinghoff
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Department of Pharmacology, Weill-Cornell Graduate School of Biomedical Sciences, New York, NY 10021, USA
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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34
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De Falco V, Buonocore P, Muthu M, Torregrossa L, Basolo F, Billaud M, Gozgit JM, Carlomagno F, Santoro M. Ponatinib (AP24534) is a novel potent inhibitor of oncogenic RET mutants associated with thyroid cancer. J Clin Endocrinol Metab 2013; 98:E811-9. [PMID: 23526464 DOI: 10.1210/jc.2012-2672] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The RET tyrosine kinase encoding gene acts as a dominantly transforming oncogene in thyroid carcinoma and other malignancies. Ponatinib (AP24534) is an oral ATP-competitive tyrosine kinase inhibitor that is in advanced clinical experimentation in leukemia. OBJECTIVE We tested whether ponatinib inhibited RET kinase and oncogenic activity. METHODS Ponatinib activity was studied by an in vitro RET immunocomplex kinase assay and immunoblotting. The effects of ponatinib on proliferation of human TT, MZ-CRC-1, and TPC-1 thyroid carcinoma cells, which harbor endogenous oncogenic RET alleles, and of NIH3T3 fibroblasts transfected with oncogenic RET mutants were determined. Ponatinib activity on TT cell xenografted tumors in athymic mice was measured. RESULTS Ponatinib inhibited immunopurified RET kinase at the IC₅₀ of 25.8 nM (95% confidence interval [CI] = 23.15-28.77 nM). It also inhibited (IC₅₀ = 33.9 nM; 95% CI = 26.41-43.58 nM) kinase activity of RET/V804M, a RET mutant displaying resistance to other tyrosine kinase inhibitor. Ponatinib blunted phosphorylation of point-mutant and rearranged RET-derived oncoproteins and inhibited proliferation of RET-transformed fibroblasts and RET mutant thyroid carcinoma cells. Finally, after 3 weeks of treatment with ponatinib (30 mg/kg/d), the volume of TT cell (medullary thyroid carcinoma) xenografts was reduced from 133 mm³ to an unmeasurable size (difference = 133 mm³, 95% CI = -83 to 349 mm³) (P < .001). Ponatinib-treated TT cell tumors displayed a reduction in the mitotic index, RET phosphorylation, and signaling. CONCLUSIONS Ponatinib is a potent inhibitor of RET kinase and has promising preclinical activity in models of RET-driven medullary thyroid carcinoma.
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Affiliation(s)
- Valentina De Falco
- Istituto di Endocrinologia ed Oncologia Sperimentale del Consiglio Nazionale delle Ricerche, Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, 80131 Naples, Italy
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35
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Osorio-Fuentealba C, Contreras-Ferrat AE, Altamirano F, Espinosa A, Li Q, Niu W, Lavandero S, Klip A, Jaimovich E. Electrical stimuli release ATP to increase GLUT4 translocation and glucose uptake via PI3Kγ-Akt-AS160 in skeletal muscle cells. Diabetes 2013; 62:1519-26. [PMID: 23274898 PMCID: PMC3636621 DOI: 10.2337/db12-1066] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Skeletal muscle glucose uptake in response to exercise is preserved in insulin-resistant conditions, but the signals involved are debated. ATP is released from skeletal muscle by contractile activity and can autocrinely signal through purinergic receptors, and we hypothesized it may influence glucose uptake. Electrical stimulation, ATP, and insulin each increased fluorescent 2-NBD-Glucose (2-NBDG) uptake in primary myotubes, but only electrical stimulation and ATP-dependent 2-NBDG uptake were inhibited by adenosine-phosphate phosphatase and by purinergic receptor blockade (suramin). Electrical stimulation transiently elevated extracellular ATP and caused Akt phosphorylation that was additive to insulin and inhibited by suramin. Exogenous ATP transiently activated Akt and, inhibiting phosphatidylinositol 3-kinase (PI3K) or Akt as well as dominant-negative Akt mutant, reduced ATP-dependent 2-NBDG uptake and Akt phosphorylation. ATP-dependent 2-NBDG uptake was also inhibited by the G protein βγ subunit-interacting peptide βark-ct and by the phosphatidylinositol 3-kinase-γ (PI3Kγ) inhibitor AS605240. ATP caused translocation of GLUT4myc-eGFP to the cell surface, mechanistically mediated by increased exocytosis involving AS160/Rab8A reduced by dominant-negative Akt or PI3Kγ kinase-dead mutants, and potentiated by myristoylated PI3Kγ. ATP stimulated 2-NBDG uptake in normal and insulin-resistant adult muscle fibers, resembling the reported effect of exercise. Hence, the ATP-induced pathway may be tapped to bypass insulin resistance.
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Affiliation(s)
- Cesar Osorio-Fuentealba
- Center for Molecular Studies of the Cell, Biomedical Sciences Institute, Universidad de Chile, Santiago, Chile
| | - Ariel E. Contreras-Ferrat
- Center for Molecular Studies of the Cell, Biomedical Sciences Institute, Universidad de Chile, Santiago, Chile
| | - Francisco Altamirano
- Center for Molecular Studies of the Cell, Biomedical Sciences Institute, Universidad de Chile, Santiago, Chile
| | - Alejandra Espinosa
- Center for Molecular Studies of the Cell, Biomedical Sciences Institute, Universidad de Chile, Santiago, Chile
- School of Medical Technology, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Qing Li
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Wenyan Niu
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Sergio Lavandero
- Center for Molecular Studies of the Cell, Biomedical Sciences Institute, Universidad de Chile, Santiago, Chile
- Faculty of Pharmaceutical and Chemical Sciences, Universidad de Chile, Santiago, Chile
- Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, Texas
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Enrique Jaimovich
- Center for Molecular Studies of the Cell, Biomedical Sciences Institute, Universidad de Chile, Santiago, Chile
- Corresponding author: Enrique Jaimovich,
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36
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Liu M, Bender SA, Cuny GD, Sherman W, Glicksman M, Ray SS. Type II kinase inhibitors show an unexpected inhibition mode against Parkinson's disease-linked LRRK2 mutant G2019S. Biochemistry 2013; 52:1725-36. [PMID: 23379419 PMCID: PMC3966205 DOI: 10.1021/bi3012077] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A number of well-known type II inhibitors (ATP-noncompetitive) that bind kinases in their DFG-out conformation were tested against wild-type LRRK2 and the most common Parkinson's disease-linked mutation, G2019S. We found that traditional type II inhibitors exhibit surprising variability in their inhibition mechanism between the wild type (WT) and the G2019S mutant of LRRK2. The type II kinase inhibitors were found to work in an ATP-competitive fashion against the G2019S mutant, whereas they appear to follow the expected noncompetitive mechanism against WT. Because the G2019S mutation lies in the DXG motif (DYG in LRRK2 but DFG in most other kinases) of the activation loop, we explored the structural consequence of the mutation on loop dynamics using an enhanced sampling method called metadynamics. The simulations suggest that the G2019S mutation stabilizes the DYG-in state of LRRK2 through a series of hydrogen bonds, leading to an increase in the conformational barrier between the active and inactive forms of the enzyme and a relative stabilization of the active form. The conformational bias toward the active form of LRRK2 mutants has two primary consequences. (1) The mutant enzyme becomes hyperactive, a known contributor to the Parkinsonian phenotype, as a consequence of being "locked" into the activated state, and (2) the mutation creates an unusual allosteric pocket that can bind type II inhibitors but in an ATP-competitive fashion. Our results suggest that developing type II inhibitors, which are generally considered superior to type I inhibitors because of desirable selectivity profiles, might be especially challenging for the G2019S LRRK2 mutant.
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Affiliation(s)
- Min Liu
- Harvard NeuroDiscovery Center, Harvard University, 65 Landsdowne St., #452, Cambridge, MA 02139
| | | | - Gregory D Cuny
- Harvard NeuroDiscovery Center, Harvard University, 65 Landsdowne St., #452, Cambridge, MA 02139
| | - Woody Sherman
- Schrodinger, 120 W. 45 Street, New York, NY, 10036
- Proteus Discovery Inc. 411 Massachusetts avenue, Cambridge, MA 02139-410
| | - Marcie Glicksman
- Harvard NeuroDiscovery Center, Harvard University, 65 Landsdowne St., #452, Cambridge, MA 02139
| | - Soumya S. Ray
- Harvard NeuroDiscovery Center, Harvard University, 65 Landsdowne St., #452, Cambridge, MA 02139
- Department of Neurology, Brigham and Women’s Hospital
- Center for Neurologic Diseases, Brigham and Women’s Hospital
- Proteus Discovery Inc. 411 Massachusetts avenue, Cambridge, MA 02139-410
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37
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Leach K, Wen A, Cook AE, Sexton PM, Conigrave AD, Christopoulos A. Impact of clinically relevant mutations on the pharmacoregulation and signaling bias of the calcium-sensing receptor by positive and negative allosteric modulators. Endocrinology 2013; 154:1105-16. [PMID: 23372019 DOI: 10.1210/en.2012-1887] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cinacalcet is predominantly used to treat secondary hyperparathyroidism due to end-stage renal failure, but, more recently, its potential clinical efficacy in treating patients with loss-of-function mutations in the calcium-sensing receptor (CaSR) has been recognized. Many clinically relevant CaSR mutations are located in the heptahelical membrane spanning and extracellular loop regions of the receptor, where allosteric modulators are predicted to bind. The aim of the present study was to investigate the impact of such mutations on the pharmacoregulation of the CaSR by the positive and negative allosteric modulators, cinacalcet and NPS-2143, respectively. Both cinacalcet and NPS-2143 effectively rescued mutants whose cell surface expression was substantially impaired, suggesting that both classes of drug can stabilize a receptor conformation that is trafficked more effectively to the cell surface. In addition, functional impairments in almost all mutant CaSRs were rescued by either cinacalcet or NPS-2143 via restoration of intracellular signaling. There was a significantly greater ability of both compounds to modulate agonist-stimulated intracellular Ca(2+) mobilization than ERK1/2 phosphorylation, indicating that the allosteric modulators engender bias in agonist-stimulated CaSR signaling to different pathways. Three mutations (G(670)R, P(748)R, and L(773)R) altered the binding affinity of allosteric modulators to the CaSR, and 3 mutations (V(817)I, L(773)R, and E(767)K) altered the cooperativity between the allosteric modulator and Ca(2+)(o). These findings have important implications for the treatment of diseases associated with CaSR mutations using allosteric CaSR modulators and for analyzing the effects of mutations on the function and pharmacoregulation of the CaSR.
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Affiliation(s)
- Katie Leach
- Monash Institute of Pharmaceutical Sciences, 399 Royal Parade, Parkville, 3052, Victoria, Australia.
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38
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Abstract
PTPN22 encodes the lymphoid tyrosine phosphatase (LYP) and is the second strongest non-HLA genetic risk factor for type 1 diabetes. The PTPN22 susceptibility allele generates an LYP variant with an arginine-to-tryptophan substitution at position 620 (R620W) that has been reported by several studies to impart a gain of function. However, a recent report investigating both human cells and a knockin mouse model containing the R620W homolog suggested that this variation causes faster protein degradation. Whether LYP R620W is a gain- or loss-of-function variant, therefore, remains controversial. To address this issue, we generated transgenic NOD mice (nonobese diabetic) in which Ptpn22 can be inducibly silenced by RNA interference. We found that Ptpn22 silencing in the NOD model replicated many of the phenotypes observed in C57BL/6 Ptpn22 knockout mice, including an increase in regulatory T cells. Notably, loss of Ptpn22 led to phenotypic changes in B cells opposite to those reported for the human susceptibility allele. Furthermore, Ptpn22 knockdown did not increase the risk of autoimmune diabetes but, rather, conferred protection from disease. Overall, to our knowledge, this is the first functional study of Ptpn22 within a model of type 1 diabetes, and the data do not support a loss of function for the PTPN22 disease variant.
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MESH Headings
- Amino Acid Substitution
- Animals
- Apoptosis
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- B-Lymphocytes/pathology
- Cell Differentiation
- Cells, Cultured
- Diabetes Mellitus, Type 1/immunology
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/pathology
- Diabetes Mellitus, Type 1/prevention & control
- Disease Models, Animal
- Enzyme Stability
- Female
- Gene Silencing
- Genetic Therapy
- Lymphocyte Activation
- Mice
- Mice, Inbred NOD
- Mice, Knockout
- Mice, Transgenic
- Mutant Proteins/antagonists & inhibitors
- Mutant Proteins/metabolism
- Protein Tyrosine Phosphatase, Non-Receptor Type 22/antagonists & inhibitors
- Protein Tyrosine Phosphatase, Non-Receptor Type 22/genetics
- Protein Tyrosine Phosphatase, Non-Receptor Type 22/metabolism
- Specific Pathogen-Free Organisms
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- T-Lymphocytes, Regulatory/pathology
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Affiliation(s)
- Peilin Zheng
- Rudolf Virchow Center, DFG Research Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Stephan Kissler
- Rudolf Virchow Center, DFG Research Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
- Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
- Corresponding author: Stephan Kissler,
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Subauste AR, Das AK, Li X, Elliot B, Evans C, El Azzouny M, Treutelaar M, Oral E, Leff T, Burant CF. Alterations in lipid signaling underlie lipodystrophy secondary to AGPAT2 mutations. Diabetes 2012; 61:2922-31. [PMID: 22872237 PMCID: PMC3478532 DOI: 10.2337/db12-0004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Congenital generalized lipodystrophy (CGL), secondary to AGPAT2 mutation is characterized by the absence of adipocytes and development of severe insulin resistance. In the current study, we investigated the adipogenic defect associated with AGPAT2 mutations. Adipogenesis was studied in muscle-derived multipotent cells (MDMCs) isolated from vastus lateralis biopsies obtained from controls and subjects harboring AGPAT2 mutations and in 3T3-L1 preadipocytes after knockdown or overexpression of AGPAT2. We demonstrate an adipogenic defect using MDMCs from control and CGL human subjects with mutated AGPAT2. This defect was rescued in CGL MDMCs with a retrovirus expressing AGPAT2. Both CGL-derived MDMCs and 3T3-L1 cells with knockdown of AGPAT2 demonstrated an increase in cell death after induction of adipogenesis. Lack of AGPAT2 activity reduces Akt activation, and overexpression of constitutively active Akt can partially restore lipogenesis. AGPAT2 modulated the levels of phosphatidic acid, lysophosphatidic acid, phosphatidylinositol species, as well as the peroxisome proliferator-activated receptor γ (PPARγ) inhibitor cyclic phosphatidic acid. The PPARγ agonist pioglitazone partially rescued the adipogenic defect in CGL cells. We conclude that AGPAT2 regulates adipogenesis through the modulation of the lipome, altering normal activation of phosphatidylinositol 3-kinase (PI3K)/Akt and PPARγ pathways in the early stages of adipogenesis.
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Affiliation(s)
- Angela R. Subauste
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Arun K. Das
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Xiangquan Li
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Brandon Elliot
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Charles Evans
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | | | - Mary Treutelaar
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Elif Oral
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Todd Leff
- Department of Pathology, Wayne State University, Detroit, Michigan
| | - Charles F. Burant
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
- Corresponding author: Charles F. Burant,
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Wolfson W. Ariad Pharmaceutical's ninja cancer drug inhibits armies of mutants. Chem Biol 2012; 19:1075-1076. [PMID: 22999871 DOI: 10.1016/j.chembiol.2012.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Trivellin G, Butz H, Delhove J, Igreja S, Chahal HS, Zivkovic V, McKay T, Patócs A, Grossman AB, Korbonits M. MicroRNA miR-107 is overexpressed in pituitary adenomas and inhibits the expression of aryl hydrocarbon receptor-interacting protein in vitro. Am J Physiol Endocrinol Metab 2012; 303:E708-19. [PMID: 22811466 DOI: 10.1152/ajpendo.00546.2011] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abnormal microRNA (miRNA) expression profiles have recently been associated with sporadic pituitary adenomas, suggesting that miRNAs can contribute to tumor formation; miRNAs are small noncoding RNAs that inhibit posttranscriptional expression of target mRNAs by binding to target sequences usually located in the 3'-UTR. In this study, we investigated the role played by miR-107, a miRNA associated with different human cancers, in sporadic pituitary adenomas and its interaction with the pituitary tumor suppressor gene aryl hydrocarbon receptor-interacting protein (AIP). miR-107 expression was evaluated in pituitary adenoma and normal pituitary samples using microRNA screen TLDA (TaqMan Low-Density Array) and RT-qPCR assays. We show that miR-107 expression was significantly upregulated in GH-secreting and nonfunctioning pituitary adenomas. We found that human AIP-3'-UTR is a target of miR-107 since miR-107 inhibited in vitro AIP expression to 53.9 ± 2% of the miRNA control in a luciferase assay and reduced endogenous AIP mRNA expression to 53 ± 22% of the miRNA control in human cells. However, we did not observe a negative correlation between AIP and miR-107 expression in the human tumor samples. Furthermore, we show that miR-107 overexpression inhibited cell proliferation in human neuroblastoma and rat pituitary adenoma cells. In conclusion, miR-107 is overexpressed in pituitary adenomas and may act as a tumor suppressor. We have identified and confirmed AIP as a miR-107 target gene. Expression data in human samples suggest that the expression of AIP and miR-107 could be influenced by a combination of tumorigenic factors as well as compensatory mechanisms stimulated by the tumorigenic process.
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Affiliation(s)
- Giampaolo Trivellin
- Dept. of Endocrinology, Barts & The London School of Medicine, Queen Mary University of London, London, UK EC1M 6BQ
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Rigat BA, Tropak MB, Buttner J, Crushell E, Benedict D, Callahan JW, Martin DR, Mahuran DJ. Evaluation of N-nonyl-deoxygalactonojirimycin as a pharmacological chaperone for human GM1 gangliosidosis leads to identification of a feline model suitable for testing enzyme enhancement therapy. Mol Genet Metab 2012; 107:203-12. [PMID: 22784478 PMCID: PMC4010500 DOI: 10.1016/j.ymgme.2012.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/12/2012] [Accepted: 06/12/2012] [Indexed: 12/26/2022]
Abstract
Deficiencies of lysosomal β-D-galactosidase can result in GM1 gangliosidosis, a severe neurodegenerative disease characterized by massive neuronal storage of GM1 ganglioside in the brain. Currently there are no available therapies that can even slow the progression of this disease. Enzyme enhancement therapy utilizes small molecules that can often cross the blood brain barrier, but are also often competitive inhibitors of their target enzyme. It is a promising new approach for treating diseases, often caused by missense mutations, associated with dramatically reduced levels of functionally folded enzyme. Despite a number of positive reports based on assays performed with patient cells, skepticism persists that an inhibitor-based treatment can increase mutant enzyme activity in vivo. To date no appropriate animal model, i.e., one that recapitulates a responsive human genotype and clinical phenotype, has been reported that could be used to validate enzyme enhancement therapy. In this report, we identify a novel enzyme enhancement-agent, N-nonyl-deoxygalactonojirimycin, that enhances the mutant β-galactosidase activity in the lysosomes of a number of patient cell lines containing a variety of missense mutations. We then demonstrate that treatment of cells from a previously described, naturally occurring feline model (that biochemically, clinically and molecularly closely mimics GM1 gangliosidosis in humans) with this molecule, results in a robust enhancement of their mutant lysosomal β-galactosidase activity. These data indicate that the feline model could be used to validate this therapeutic approach and determine the relationship between the disease stage at which this therapy is initiated and the maximum clinical benefits obtainable.
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Affiliation(s)
- Brigitte A. Rigat
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Canada M5G 1X8
| | - Michael B. Tropak
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Canada M5G 1X8
| | - Justin Buttner
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Canada M5G 1X8
| | - Ellen Crushell
- Clinical & Metabolic Genetics, The Hospital for Sick Children, Toronto, Canada M5G 1X8
| | - Daphne Benedict
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Canada M5G 1X8
| | - John W. Callahan
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Canada M5G 1X8
- Department of Biochemistry, University of Toronto, Toronto, Canada M5S 1A8
| | - Douglas R. Martin
- Scott-Ritchey Research Center and Dept. Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, AL 36849, USA
| | - Don J. Mahuran
- Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Canada M5G 1X8
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Canada M5S 1A8
- Corresponding author at: Genetics & Genome Biology Department, The Hospital for Sick Children, Room 9146 A, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8. Fax: +1 416 813 8700. (D.J. Mahuran)
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Liu R, Liu D, Xing M. The Akt inhibitor MK2206 synergizes, but perifosine antagonizes, the BRAF(V600E) inhibitor PLX4032 and the MEK1/2 inhibitor AZD6244 in the inhibition of thyroid cancer cells. J Clin Endocrinol Metab 2012; 97:E173-82. [PMID: 22090271 PMCID: PMC3275354 DOI: 10.1210/jc.2011-1054] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE The purpose of the study was to explore optimal combinations of currently actively developed drugs for dually targeting the Ras → Raf → MAPK kinase (MEK) → MAPK/ERK (MAPK) and the phosphatidylinositol 3-kinase/Akt pathways as effective treatments for thyroid cancer. EXPERIMENTAL DESIGN We tested the combinations of the Akt inhibitors MK2206 or perifosine with the BRAF(V600E) inhibitor PLX4032 or the MEK1/2 inhibitor AZD6244 in thyroid cancer cells harboring both the BRAF(V600E) and PIK3CA mutations. RESULTS We found that MK2206 could potently, when used alone, and synergistically, when combined with either PLX4032 or AZD6244, inhibit thyroid cancer cell growth with all the combination index values lower than 1. Perifosine could potently inhibit thyroid cancer cell growth when used alone, but a strong antagonism occurred between this drug and PLX4032 or AZD6244 in the inhibition of thyroid cancer cell growth with all combination index values higher than 1. Combinations of MK2206 with PLX4032 or AZD6244 dramatically enhanced G1 cell cycle arrest induced by each drug alone. However, G2 cell cycle arrest uniquely induced by perifosine alone and G1 cell cycle arrest induced by PLX4032 or AZD6244 were both reversed by combination treatments, providing a mechanism for their antagonism. All these drugs could correspondingly inhibit the MAPK and phosphatidylinositol 3-kinase/Akt signalings, confirming their expected target effects. CONCLUSIONS We demonstrated, unexpectedly, opposite outcomes of MK2206 and perifosine in their combinational treatments with BRAF(V600E)/MEK inhibitors in thyroid cancer cells. The data may help appropriate selection of these prominent drugs for clinical trials of combination therapies for thyroid cancer.
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Affiliation(s)
- Ruixin Liu
- Laboratory for Cellular and Molecular Thyroid Research, Division of Endocrinology and Metabolism, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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Goldin E, Zheng W, Motabar O, Southall N, Choi JH, Marugan J, Austin CP, Sidransky E. High throughput screening for small molecule therapy for Gaucher disease using patient tissue as the source of mutant glucocerebrosidase. PLoS One 2012; 7:e29861. [PMID: 22272254 PMCID: PMC3260169 DOI: 10.1371/journal.pone.0029861] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 12/05/2011] [Indexed: 01/11/2023] Open
Abstract
Gaucher disease (GD), the most common lysosomal storage disorder, results from the inherited deficiency of the lysosomal enzyme glucocerebrosidase (GCase). Previously, wildtype GCase was used for high throughput screening (HTS) of large collections of compounds to identify small molecule chaperones that could be developed as new therapies for GD. However, the compounds identified from HTS usually showed reduced potency later in confirmatory cell-based assays. An alternate strategy is to perform HTS on mutant enzyme to identify different lead compounds, including those enhancing mutant enzyme activities. We developed a new screening assay using enzyme extract prepared from the spleen of a patient with Gaucher disease with genotype N370S/N370S. In tissue extracts, GCase is in a more native physiological environment, and is present with the native activator saposin C and other potential cofactors. Using this assay, we screened a library of 250,000 compounds and identified novel modulators of mutant GCase including 14 new lead inhibitors and 30 lead activators. The activities of some of the primary hits were confirmed in subsequent cell-based assays using patient-derived fibroblasts. These results suggest that primary screening assays using enzyme extracted from tissues is an alternative approach to identify high quality, physiologically relevant lead compounds for drug development.
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Affiliation(s)
- Ehud Goldin
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
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Abstract
Substitutive therapy has significantly ameliorated the quality of life of patients with coagulation factor deficiencies. However, there are some limitations that support research towards alternative therapeutic approaches. Here we focus on the rescue of coagulation factor biosynthesis by targeting the RNA processing and translation, which would permit restoration of the altered gene expression while maintaining the gene regulation in the physiological tissues. The essential prerequisite of the three reported RNA-based correction approaches (i-iii), which rely on mutation types and are applicable even to large size mRNAs, is the presence in cells of the precursor (pre-mRNA) or mature mRNA forms. (i) In the F7 gene, modification of the small nuclear RNA U1 (U1 snRNA), the key component of the spliceosomal U1 ribonucleoprotein, re-directs correct usage of a mutated exon-intron junction, triggering synthesis of correct mRNA and secretion of functional factor (F)VII. (ii) Spliceosome-mediated RNA trans-splicing (SMaRT) between mutated and engineered pre-mRNAs produces normal FVIII mRNA and secretion of functional protein. (iii) Aminoglycoside drugs induce ribosome readthrough and suppress premature translation termination caused by nonsense mutations in FVII, VIII and IX. The rescued expression levels ranged from very low (aminoglycosides) to moderate (U1 snRNA and SMaRT), which could result in amelioration of the disease phenotypes. These findings prompt further studies aimed at demonstrating the clinical translatability of RNA-based strategies, which might open new avenues in the treatment of coagulation factor deficiencies.
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Affiliation(s)
- M Pinotti
- Department of Biochemistry and Molecular Biology, University of Ferrara, Trieste, Italy
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Rojas M, Arias CF, López S. Protein kinase R is responsible for the phosphorylation of eIF2alpha in rotavirus infection. J Virol 2010; 84:10457-66. [PMID: 20631127 PMCID: PMC2950594 DOI: 10.1128/jvi.00625-10] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 07/07/2010] [Indexed: 11/20/2022] Open
Abstract
The eukaryotic initiation translation factor 2 (eIF2) represents a key point in the regulation of protein synthesis. This factor delivers the initiator Met-tRNA to the ribosome, a process that is conserved in all eukaryotic cells. Many types of stress reduce global translation by triggering the phosphorylation of the α subunit of eIF2, which reduces the formation of the preinitiation translation complexes. Early during rotavirus infection, eIF2α becomes phosphorylated, and even under these conditions viral protein synthesis is not affected, while most of the cell protein synthesis is blocked. Here, we found that the kinase responsible for the phosphorylation of eIF2α in rotavirus-infected cells is PKR, since in mouse embryonic fibroblasts deficient in the kinase domain of PKR, or in MA104 cells where the expression of PKR was knocked down by RNA interference, eIF2α was not phosphorylated upon rotavirus infection. The viral component responsible for the activation of PKR seems to be viral double-stranded RNA, which is found in the cytoplasm of infected cells, outside viroplasms. Taken together, these results suggest that rotaviruses induce the PKR branch of the interferon system and have evolved a mechanism to translate its proteins, surpassing the block imposed by eIF2α phosphorylation.
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MESH Headings
- Animals
- Cell Line
- Cells, Cultured
- Enzyme Activation
- Eukaryotic Initiation Factor-2/genetics
- Eukaryotic Initiation Factor-2/metabolism
- Gene Knockdown Techniques
- Host-Pathogen Interactions/physiology
- Macaca mulatta
- Mice
- Mice, Knockout
- Mutant Proteins/antagonists & inhibitors
- Mutant Proteins/genetics
- Mutant Proteins/metabolism
- Phosphorylation
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Ribosome Subunits, Small, Eukaryotic/metabolism
- Ribosome Subunits, Small, Eukaryotic/virology
- Rotavirus/genetics
- Rotavirus/pathogenicity
- Rotavirus/physiology
- Rotavirus Infections/metabolism
- Transfection
- Viral Proteins/biosynthesis
- eIF-2 Kinase/antagonists & inhibitors
- eIF-2 Kinase/deficiency
- eIF-2 Kinase/genetics
- eIF-2 Kinase/metabolism
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Affiliation(s)
- Margarito Rojas
- Departamento de Génetica del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, Morelos 62210, México
| | - Carlos F. Arias
- Departamento de Génetica del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, Morelos 62210, México
| | - Susana López
- Departamento de Génetica del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, Morelos 62210, México
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Xie Z, Chng WJ, Tay KG, Liu SC, Zhou J, Chen CS. Therapeutic potential of antisense oligodeoxynucleotides in downregulating p53 oncogenic mutations in cancers. Biotechnol Lett 2010; 33:221-8. [PMID: 20882314 DOI: 10.1007/s10529-010-0423-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 09/15/2010] [Indexed: 12/22/2022]
Abstract
PURPOSE OF WORK mutation of the p53 gene is the most common genetic alteration in human cancers. Our study proposes to rationally design a p53 antisense oligonucleotide (ASO) repository, which contains a series of ASOs containing single nucleotide differences to discriminate between each mutant and wild type (WT) p53. The Sfold software was used to predict target-accessibility and we designed an initial series of antisense oligonucleotides (ASO) that target the p53 mutants A161T, R175H and R249S. Western-blot analysis indicated that ASOs strongly inhibited the expression of p53 mutants in a panel of human tumor cell lines (SNU-449, SK-BR-3 and PLC/PRF/5) while having little effect on the expression of WT p53 (HepG2 cells). In three cancer lines harboring each of the p53 mutations, mutant-specific ASO treatment led to a dose-dependent inhibition of cell growth, cell viability, colony formation and invasion, and expression of mutant p53-dependent survival proteins. Our preliminary results indicate that a single nucleotide difference in ASOs can discriminate between mutant and WT p53. These observations support the hypothesis that a p53 ASO repository can be a potentially valuable tool to knock down oncogenic mutant p53 and warrant the testing of a p53 ASO repository in in vivo settings.
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Affiliation(s)
- Zhigang Xie
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117456, Singapore
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Sridaran S, McClintock SK, Syphard LM, Herman KM, Barnwell JW, Udhayakumar V. Anti-folate drug resistance in Africa: meta-analysis of reported dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) mutant genotype frequencies in African Plasmodium falciparum parasite populations. Malar J 2010; 9:247. [PMID: 20799995 PMCID: PMC2940896 DOI: 10.1186/1475-2875-9-247] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 08/30/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes of Plasmodium falciparum are associated with resistance to anti-folate drugs, most notably sulphadoxine-pyrimethamine (SP). Molecular studies document the prevalence of these mutations in parasite populations across the African continent. However, there is no systematic review examining the collective epidemiological significance of these studies. This meta-analysis attempts to: 1) summarize genotype frequency data that are critical for molecular surveillance of anti-folate resistance and 2) identify the specific challenges facing the development of future molecular databases. METHODS This review consists of 220 studies published prior to 2009 that report the frequency of select dhfr and dhps mutations in 31 African countries. Maps were created to summarize the location and prevalence of the highly resistant dhfr triple mutant (N51I, C59R, S108N) genotype and dhps double mutant (A437G and K540E) genotype in Africa. A hierarchical mixed effects logistic regression was used to examine the influence of various factors on reported mutant genotype frequency. These factors include: year and location of study, age and clinical status of sampled population, and reporting conventions for mixed genotype data. RESULTS A database consisting of dhfr and dhps mutant genotype frequencies from all African studies that met selection criteria was created for this analysis. The map illustrates particularly high prevalence of both the dhfr triple and dhps double mutant genotypes along the Kenya-Tanzania border and Malawi. The regression model shows a statistically significant increase in the prevalence of both the dhfr triple and dhps double mutant genotypes in Africa. CONCLUSION Increasing prevalence of the dhfr triple mutant and dhps double mutant genotypes in Africa are consistent with the loss of efficacy of SP for treatment of clinical malaria in most parts of this continent. Continued assessment of the effectiveness of SP for the treatment of clinical malaria and intermittent preventive treatment in pregnancy is needed. The creation of a centralized resistance data network, such as the one proposed by the WorldWide Antimalarial Resistance Network (WWARN), will become a valuable resource for planning timely actions to combat drug resistant malaria.
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Affiliation(s)
- Sankar Sridaran
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton road NE, Mail Stop D-67 Atlanta, GA, 30333, USA.
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Abstract
ERK8 is the most recent addition for the MAPK family, and its mechanism of activation and function are not yet known, mainly due to the lack of any known physiological stimulator. In this report, we describe the preparation of reagents for the use of a novel method, the ligand interaction scan (LIScan), to study the function of this protein kinase. We generated a set of mutants of ERK8, and identified inhibited as well as stimulated forms. By specifically inhibiting or stimulating the mutants of ERK8, we show that the ERK8-induced inhibition of proliferation is altered. Moreover, we used the developed mutants to show for the first time that ERK8 translocates to the nucleus upon activation. The use of methods such as the ligand interaction scan may thus promote the analyses of the functions of uncharacterized proteins such as ERK8, and possibly help in controlling the activity of target proteins in various experimental systems and applications.
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Affiliation(s)
- Oran Erster
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
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