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Zessin M, Meleshin M, Hilscher S, Schiene-Fischer C, Barinka C, Jung M, Schutkowski M. Continuous Fluorescent Sirtuin Activity Assay Based on Fatty Acylated Lysines. Int J Mol Sci 2023; 24:ijms24087416. [PMID: 37108579 PMCID: PMC10138348 DOI: 10.3390/ijms24087416] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/06/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Lysine deacetylases, like histone deacetylases (HDACs) and sirtuins (SIRTs), are involved in many regulatory processes such as control of metabolic pathways, DNA repair, and stress responses. Besides robust deacetylase activity, sirtuin isoforms SIRT2 and SIRT3 also show demyristoylase activity. Interestingly, most of the inhibitors described so far for SIRT2 are not active if myristoylated substrates are used. Activity assays with myristoylated substrates are either complex because of coupling to enzymatic reactions or time-consuming because of discontinuous assay formats. Here we describe sirtuin substrates enabling direct recording of fluorescence changes in a continuous format. Fluorescence of the fatty acylated substrate is different when compared to the deacylated peptide product. Additionally, the dynamic range of the assay could be improved by the addition of bovine serum albumin, which binds the fatty acylated substrate and quenches its fluorescence. The main advantage of the developed activity assay is the native myristoyl residue at the lysine side chain avoiding artifacts resulting from the modified fatty acyl residues used so far for direct fluorescence-based assays. Due to the extraordinary kinetic constants of the new substrates (KM values in the low nM range, specificity constants between 175,000 and 697,000 M-1s-1) it was possible to reliably determine the IC50 and Ki values for different inhibitors in the presence of only 50 pM of SIRT2 using different microtiter plate formats.
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Affiliation(s)
- Matthes Zessin
- Department of Medicinal Chemistry, Institute of Pharmacy, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - Marat Meleshin
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - Sebastian Hilscher
- Department of Medicinal Chemistry, Institute of Pharmacy, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - Cordelia Schiene-Fischer
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - Cyril Barinka
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Prumyslova 595, 25250 Vestec, Czech Republic
| | - Manfred Jung
- Institute of Pharmaceutical Sciences, University of Freiburg, Albertstraße 25, 79104 Freiburg, Germany
| | - Mike Schutkowski
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
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2
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Zessin M, Meleshin M, Simic Z, Kalbas D, Arbach M, Gebhardt P, Melesina J, Liebscher S, Bordusa F, Sippl W, Barinka C, Schutkowski M. Continuous Sirtuin/HDAC (histone deacetylase) activity assay using thioamides as PET (Photoinduced Electron Transfer)-based fluorescence quencher. Bioorg Chem 2021; 117:105425. [PMID: 34695733 DOI: 10.1016/j.bioorg.2021.105425] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/07/2021] [Accepted: 10/09/2021] [Indexed: 12/28/2022]
Abstract
Histone deacylase 11 and human sirtuins are able to remove fatty acid-derived acyl moieties from the ε-amino group of lysine residues. Specific substrates are needed for investigating the biological functions of these enzymes. Additionally, appropriate screening systems are required for identification of modulators of enzymatic activities of HDAC11 and sirtuins. We designed and synthesized a set of activity probes by incorporation of a thioamide quencher unit into the fatty acid-derived acyl chain and a fluorophore in the peptide sequence. Systematic variation of both fluorophore and quencher position resulted "super-substrates" with catalytic constants of up to 15,000,000 M-1s-1 for human sirtuin 2 (Sirt2) enabling measurements using enzyme concentrations down to 100 pM in microtiter plate-based screening formats. It could be demonstrated that the stalled intermediate formed by the reaction of Sirt2-bound thiomyristoylated peptide and NAD+ has IC50 values below 200 pM.
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Affiliation(s)
- Matthes Zessin
- Department of Medicinal Chemistry, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Marat Meleshin
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Zeljko Simic
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Diana Kalbas
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Miriam Arbach
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Philip Gebhardt
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Jelena Melesina
- Department of Medicinal Chemistry, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Sandra Liebscher
- Department of Natural Product Biochemistry, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Frank Bordusa
- Department of Natural Product Biochemistry, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Wolfgang Sippl
- Department of Medicinal Chemistry, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Cyril Barinka
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Mike Schutkowski
- Department of Enzymology, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany.
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3
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Desaulniers D, Vasseur P, Jacobs A, Aguila MC, Ertych N, Jacobs MN. Integration of Epigenetic Mechanisms into Non-Genotoxic Carcinogenicity Hazard Assessment: Focus on DNA Methylation and Histone Modifications. Int J Mol Sci 2021; 22:10969. [PMID: 34681626 PMCID: PMC8535778 DOI: 10.3390/ijms222010969] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
Epigenetics involves a series of mechanisms that entail histone and DNA covalent modifications and non-coding RNAs, and that collectively contribute to programing cell functions and differentiation. Epigenetic anomalies and DNA mutations are co-drivers of cellular dysfunctions, including carcinogenesis. Alterations of the epigenetic system occur in cancers whether the initial carcinogenic events are from genotoxic (GTxC) or non-genotoxic (NGTxC) carcinogens. NGTxC are not inherently DNA reactive, they do not have a unifying mode of action and as yet there are no regulatory test guidelines addressing mechanisms of NGTxC. To fil this gap, the Test Guideline Programme of the Organisation for Economic Cooperation and Development is developing a framework for an integrated approach for the testing and assessment (IATA) of NGTxC and is considering assays that address key events of cancer hallmarks. Here, with the intent of better understanding the applicability of epigenetic assays in chemical carcinogenicity assessment, we focus on DNA methylation and histone modifications and review: (1) epigenetic mechanisms contributing to carcinogenesis, (2) epigenetic mechanisms altered following exposure to arsenic, nickel, or phenobarbital in order to identify common carcinogen-specific mechanisms, (3) characteristics of a series of epigenetic assay types, and (4) epigenetic assay validation needs in the context of chemical hazard assessment. As a key component of numerous NGTxC mechanisms of action, epigenetic assays included in IATA assay combinations can contribute to improved chemical carcinogen identification for the better protection of public health.
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Affiliation(s)
- Daniel Desaulniers
- Environmental Health Sciences and Research Bureau, Hazard Identification Division, Health Canada, AL:2203B, Ottawa, ON K1A 0K9, Canada
| | - Paule Vasseur
- CNRS, LIEC, Université de Lorraine, 57070 Metz, France;
| | - Abigail Jacobs
- Independent at the Time of Publication, Previously US Food and Drug Administration, Rockville, MD 20852, USA;
| | - M. Cecilia Aguila
- Toxicology Team, Division of Human Food Safety, Center for Veterinary Medicine, US Food and Drug Administration, Department of Health and Human Services, Rockville, MD 20852, USA;
| | - Norman Ertych
- German Centre for the Protection of Laboratory Animals (Bf3R), German Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany;
| | - Miriam N. Jacobs
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton OX11 0RQ, UK;
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4
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Amjadi M, Hallaj T, Hildebrandt N. A sensitive homogeneous enzyme assay for euchromatic histone-lysine-N-methyltransferase 2 (G9a) based on terbium-to-quantum dot time-resolved FRET. ACTA ACUST UNITED AC 2020; 11:173-179. [PMID: 34336605 PMCID: PMC8314039 DOI: 10.34172/bi.2021.23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 06/01/2020] [Accepted: 06/13/2020] [Indexed: 12/20/2022]
Abstract
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Introduction: Histone modifying enzymes include several classes of enzymes that are responsible for various post-translational modifications of histones such as methylation and acetylation. They are important epigenetic factors, which may involve several diseases and so their assay, as well as screening of their inhibitors, are of great importance. Herein, a bioassay based on terbium-to-quantum dot (Tb-to-QD) time-resolved Förster resonance energy transfer (TR-FRET) was developed for monitoring the activity of G9a, the euchromatic histone-lysine N-methyltransferase 2. Overexpression of G9a has been reported in some cancers such as ovarian carcinoma, lung cancer, multiple myeloma and brain cancer. Thus, inhibition of this enzyme is important for therapeutic purposes. Methods: In this assay, a biotinylated peptide was used as a G9a substrate in conjugation with streptavidin-coated ZnS/CdSe QD as FRET acceptor, and an anti-mark antibody labeled with Tb as a donor. Time-resolved fluorescence was used for measuring FRET ratios. Results: We examined three QDs, with emission wavelengths of 605, 655 and 705 nm, as FRET acceptors and investigated FRET efficiency between the Tb complex and each of them. Since the maximum FRET efficiency was obtained for Tb to QD705 (more than 50%), this pair was exploited for designing the enzyme assay. We showed that the method has excellent sensitivity and selectivity for the determination of G9a at concentrations as low as 20 pM. Furthermore, the designed assay was applied for screening of an enzyme inhibitor, S-(5’-Adenosyl)-L-homocysteine (SAH). Conclusion: It was shown that Tb-to-QD FRET is an outstanding platform for developing a homogenous assay for the G9a enzyme and its inhibitors. The obtained results confirmed that this assay was quite sensitive and could be used in the field of inhibitor screening.
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Affiliation(s)
- Mohammad Amjadi
- Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 5166616471, Iran
| | - Tooba Hallaj
- Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 5166616471, Iran.,Cellular and Molecular Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, Iran
| | - Niko Hildebrandt
- NanoBioPhotonics (nanofret.com), Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, Université Paris-Sud, CNRS, CEA, Orsay, France.,Laboratoire Chimie Organique, Bioorganique, Réactivité et Analyse (COBRA), Université de Rouen Normandie, CNRS, INSA, 76821 Mont-Saint-Aignan, France
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5
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Hallaj T, Amjadi M, Qiu X, Susumu K, Medintz IL, Hildebrandt N. Terbium-to-quantum dot Förster resonance energy transfer for homogeneous and sensitive detection of histone methyltransferase activity. NANOSCALE 2020; 12:13719-13730. [PMID: 32573632 DOI: 10.1039/d0nr03383a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The development of rapid, simple, and versatile biosensors for monitoring the activity of histone modifying enzymes (HMEs) is needed for the improvement of diagnostic assays, screening of HME inhibitors, and a better understanding of HME kinetics in different environments. Nanoparticles can play an important role in this regard by improving or complementing currently available enzyme detection technologies. Here, we present the development and application of a homogeneous methyltransferase (SET7/9) assay based on time-gated Förster resonance energy transfer (TG-FRET) between terbium complexes (Tb) and luminescent semiconductor quantum dots (QDs). Specific binding of a Tb-antibody conjugate to a SET7/9-methylated Lys4 on a histone H3(1-21) peptide substrate attached to the QD surface resulted in efficient FRET and provided the mechanism for monitoring the SET7/9 activity. Two common peptide-QD attachment strategies (biotin-streptavidin and polyhistidine-mediated self-assembly), two different QD colors (625 and 705 nm), and enzyme sensing with post- or pre-assembled QD-peptide conjugates demonstrated the broad applicability of this assay design. Limits of detection in the low picomolar concentration range, high selectivity tested against non-specific antibodies, enzymes, and co-factors, determination of the inhibition constants of the SET7/9 inhibitors SAH and (R)-PFI-2, and analysis of the co-factor (SAM) concentration-dependent enzyme kinetics of SET7/9 which followed the Michaelis-Menten model highlighted the excellent performance of this TG-FRET HME activity assay.
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Affiliation(s)
- Tooba Hallaj
- Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 5166616471, Iran. and Cellular and Molecular Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia 5714783734, Iran
| | - Mohammad Amjadi
- Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 5166616471, Iran.
| | - Xue Qiu
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France and School of Medicine and Pharmacy, Ocean University of China. 5, Yushan Road, 266003 Qingdao, Shandong, China
| | - Kimihiro Susumu
- Optical Sciences Division, Code 5600, U.S. Naval Research Laboratory, Washington, D.C. 20375, USA and KeyW Corporation, Hanover, Maryland 21076, USA
| | - Igor L Medintz
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, D.C. 20375, USA
| | - Niko Hildebrandt
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France and nanoFRET.com, Laboratoire COBRA (Chimie Organique, Bioorganique, Réactivité et Analyse), Université de Rouen Normandie, CNRS, INSA, 76821 Mont-Saint-Aignan, France.
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6
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Li ASM, Li F, Eram MS, Bolotokova A, Dela Seña CC, Vedadi M. Chemical probes for protein arginine methyltransferases. Methods 2019; 175:30-43. [PMID: 31809836 DOI: 10.1016/j.ymeth.2019.11.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/29/2019] [Accepted: 11/29/2019] [Indexed: 12/28/2022] Open
Abstract
Protein arginine methyltransferases (PRMTs) catalyze the transfer of methyl groups to specific arginine residues of their substrates using S-adenosylmethionine as a methyl donor, contributing to regulation of many biological processes including transcription, and DNA damage repair. Dysregulation of PRMT expression is often associated with various diseases including cancers. Different methods have been used to characterize the activities of PRMTs and determine their kinetic parameters including mass spectrometry, radiometric, and antibody-based assays. Here, we present kinetic characterization of PRMTs using a radioactivity-based assay for better comparison along with previously reported values. We also report on full characterization of PRMT9 activity with SAP145 peptide as substrate. We further review the potent, selective and cell-active PRMT inhibitors discovered in recent years to provide a better understanding of available tools to investigate the roles these proteins play in health and disease.
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Affiliation(s)
- Alice Shi Ming Li
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Fengling Li
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Mohammad S Eram
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Albina Bolotokova
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Carlo C Dela Seña
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Masoud Vedadi
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
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7
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Kutil Z, Mikešová J, Zessin M, Meleshin M, Nováková Z, Alquicer G, Kozikowski A, Sippl W, Bařinka C, Schutkowski M. Continuous Activity Assay for HDAC11 Enabling Reevaluation of HDAC Inhibitors. ACS OMEGA 2019; 4:19895-19904. [PMID: 31788622 PMCID: PMC6882135 DOI: 10.1021/acsomega.9b02808] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/18/2019] [Indexed: 05/05/2023]
Abstract
Histone deacetylase 11 (HDAC11) preferentially removes fatty acid residues from lysine side chains in a peptide or protein environment. Here, we report the development and validation of a continuous fluorescence-based activity assay using an internally quenched TNFα-derived peptide derivative as a substrate. The threonine residue in the +1 position was replaced by the quencher amino acid 3'-nitro-l-tyrosine and the fatty acyl moiety substituted by 2-aminobenzoylated 11-aminoundecanoic acid. The resulting peptide substrate enables fluorescence-based direct and continuous readout of HDAC11-mediated amide bond cleavage fully compatible with high-throughput screening formats. The Z'-factor is higher than 0.85 for the 15 μM substrate concentration, and the signal-to-noise ratio exceeds 150 for 384-well plates. In the absence of NAD+, this substrate is specific for HDAC11. Reevaluation of inhibitory data using our novel assay revealed limited potency and selectivity of known HDAC inhibitors, including Elevenostat, a putative HDAC11-specific inhibitor.
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Affiliation(s)
- Zsófia Kutil
- Institute
of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Jana Mikešová
- Institute
of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Matthes Zessin
- Department
of Medicinal Chemistry, Institute of Pharmacy, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Marat Meleshin
- Department
of Enzymology, Institute of Biochemistry and Biotechnology, Charles
Tanford Protein Centre, Martin Luther University
Halle-Wittenberg, Kurt-Mothes-Straße
3a, 06120 Halle
(Saale), Germany
| | - Zora Nováková
- Institute
of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Glenda Alquicer
- Institute
of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Alan Kozikowski
- StarWise
Therapeutics LLC, 505
S Rosa Road, Suite 27, Madison, Wisconsin 53719-1235, United States
| | - Wolfgang Sippl
- Department
of Medicinal Chemistry, Institute of Pharmacy, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Cyril Bařinka
- Institute
of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
- E-mail: . Tel.: +420-325-873-777 (C.B.)
| | - Mike Schutkowski
- Department
of Enzymology, Institute of Biochemistry and Biotechnology, Charles
Tanford Protein Centre, Martin Luther University
Halle-Wittenberg, Kurt-Mothes-Straße
3a, 06120 Halle
(Saale), Germany
- E-mail: . Tel.: +49-345-5524-828 (M.S.)
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8
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Zessin M, Kutil Z, Meleshin M, Nováková Z, Ghazy E, Kalbas D, Marek M, Romier C, Sippl W, Bařinka C, Schutkowski M. One-Atom Substitution Enables Direct and Continuous Monitoring of Histone Deacylase Activity. Biochemistry 2019; 58:4777-4789. [PMID: 31682411 DOI: 10.1021/acs.biochem.9b00786] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We developed a one-step direct assay for the determination of histone deacylase (HDAC) activity by substituting the carbonyl oxygen of the acyl moiety with sulfur, resulting in thioacylated lysine side chains. This modification is recognized by class I HDACs with different efficiencies ranging from not accepted for HDAC1 to kinetic constants similar to that of the parent oxo substrate for HDAC8. Class II HDACs can hydrolyze thioacylated substrates with approximately 5-10-fold reduced kcat values, which resembles the effect of thioamide substitution in metallo-protease substrates. Class IV HDAC11 accepts thiomyristoyl modification less efficiently with an ∼5-fold reduced specificity constant. On the basis of the unique spectroscopic properties of thioamide bonds (strong absorption in spectral range of 260-280 nm and efficient fluorescence quenching), HDAC-mediated cleavage of thioamides could be followed by ultraviolet-visible and fluorescence spectroscopy in a continuous manner. The HDAC activity assay is compatible with microtiter plate-based screening formats up to 1536-well plates with Z' factors of >0.75 and signal-to-noise ratios of >50. Using thioacylated lysine residues in p53-derived peptides, we optimized substrates for HDAC8 with a catalytic efficiency of >250000 M-1 s-1, which are more than 100-fold more effective than most of the known substrates. We determined inhibition constants of several inhibitors for human HDACs using thioacylated peptidic substrates and found good correlation with the values from the literature. On the other hand, we could introduce N-methylated, N-acylated lysine residues as inhibitors for HDACs with an IC50 value of 1 μM for an N-methylated, N-myristoylated peptide derivative and human HDAC11.
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Affiliation(s)
- Matthes Zessin
- Department of Medicinal Chemistry, Institute of Pharmacy , Martin-Luther-University Halle-Wittenberg , 06120 Halle/Saale , Germany
| | - Zsófia Kutil
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV , Prumyslova 595 , 252 50 Vestec , Czech Republic
| | - Marat Meleshin
- Department of Enzymology, Institute of Biochemistry and Biotechnology, Charles-Tanford-Protein Center , Martin-Luther-University Halle-Wittenberg , 06120 Halle/Saale , Germany
| | - Zora Nováková
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV , Prumyslova 595 , 252 50 Vestec , Czech Republic
| | - Ehab Ghazy
- Department of Medicinal Chemistry, Institute of Pharmacy , Martin-Luther-University Halle-Wittenberg , 06120 Halle/Saale , Germany
| | - Diana Kalbas
- Department of Enzymology, Institute of Biochemistry and Biotechnology, Charles-Tanford-Protein Center , Martin-Luther-University Halle-Wittenberg , 06120 Halle/Saale , Germany
| | - Martin Marek
- Departement de Biologie Structurale Integrative, Institut de Genetique et Biologie Moleculaire et Cellulaire (IGBMC) , Universite de Strasbourg (UDS), CNRS, INSERM , 1 rue Laurent Fries, B.P. 10142 , 67404 Illkirch Cedex IGBMC, France
| | - Christophe Romier
- Departement de Biologie Structurale Integrative, Institut de Genetique et Biologie Moleculaire et Cellulaire (IGBMC) , Universite de Strasbourg (UDS), CNRS, INSERM , 1 rue Laurent Fries, B.P. 10142 , 67404 Illkirch Cedex IGBMC, France
| | - Wolfgang Sippl
- Department of Medicinal Chemistry, Institute of Pharmacy , Martin-Luther-University Halle-Wittenberg , 06120 Halle/Saale , Germany
| | - Cyril Bařinka
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV , Prumyslova 595 , 252 50 Vestec , Czech Republic
| | - Mike Schutkowski
- Department of Enzymology, Institute of Biochemistry and Biotechnology, Charles-Tanford-Protein Center , Martin-Luther-University Halle-Wittenberg , 06120 Halle/Saale , Germany
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9
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He M, Han Z, Liu L, Zheng YG. Untersuchung der epigenetischen Funktionen von Lysin‐Acetyltransferasen mit Methoden der chemischen Biologie. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Maomao He
- Department of Pharmaceutical and Biochemical Sciences and Department of Statistics University of Georgia Athens Georgia 30602 USA
| | - Zhen Han
- Department of Pharmaceutical and Biochemical Sciences and Department of Statistics University of Georgia Athens Georgia 30602 USA
| | - Liang Liu
- Department of Pharmaceutical and Biochemical Sciences and Department of Statistics University of Georgia Athens Georgia 30602 USA
| | - Y. George Zheng
- Department of Pharmaceutical and Biochemical Sciences and Department of Statistics University of Georgia Athens Georgia 30602 USA
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10
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He M, Han Z, Liu L, Zheng YG. Chemical Biology Approaches for Investigating the Functions of Lysine Acetyltransferases. Angew Chem Int Ed Engl 2017; 57:1162-1184. [PMID: 28786225 DOI: 10.1002/anie.201704745] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Indexed: 12/20/2022]
Abstract
The side-chain acetylation of lysine residues in histones and non-histone proteins catalyzed by lysine acetyltransferases (KATs) represents a widespread posttranslational modification (PTM) in the eukaryotic cells. Lysine acetylation plays regulatory roles in major cellular pathways inside and outside the nucleus. In particular, KAT-mediated histone acetylation has an effect on all DNA-templated epigenetic processes. Aberrant expression and activation of KATs are commonly observed in human diseases, especially cancer. In recent years, the study of KAT functions in biology and disease has greatly benefited from chemical biology tools and strategies. In this Review, we present the past and current accomplishments in the design of chemical biology approaches for the interrogation of KAT activity and function. These methods and probes are classified according to their mechanisms of action and respective applications, with both strengths and limitations discussed.
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Affiliation(s)
- Maomao He
- Department of Pharmaceutical and Biochemical Sciences and Department of Statistics, University of Georgia, Athens, Georgia, 30602 (U, SA
| | - Zhen Han
- Department of Pharmaceutical and Biochemical Sciences and Department of Statistics, University of Georgia, Athens, Georgia, 30602 (U, SA
| | - Liang Liu
- Department of Pharmaceutical and Biochemical Sciences and Department of Statistics, University of Georgia, Athens, Georgia, 30602 (U, SA
| | - Y George Zheng
- Department of Pharmaceutical and Biochemical Sciences and Department of Statistics, University of Georgia, Athens, Georgia, 30602 (U, SA
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11
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Duchin S, Vershinin Z, Levy D, Aharoni A. A continuous kinetic assay for protein and DNA methyltransferase enzymatic activities. Epigenetics Chromatin 2015; 8:56. [PMID: 26675044 PMCID: PMC4678762 DOI: 10.1186/s13072-015-0048-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 11/25/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Methyltransferases (MTs) catalyze the S-adenosylmethionine (SAM)-dependent methylation of a wide variety of protein and DNA substrates. Methylation of lysine, arginine or cytosine regulates a variety of biological processes including transcriptional activation and gene silencing. Despite extensive studies of the cellular roles of MTs, their quantitative kinetic characterization remains challenging. In the past decade, several assays have been developed to monitor methyl transfer activity utilizing different approaches including radiolabeling, antibodies or mass-spectrometry analysis. However, each approach suffers from different limitation and no easy continuous assay for detection of MT activity exists. RESULTS We have developed a continuous coupled assay for the general detection of MTs activity. In this assay, the formation of S-adenosylhomocysteine (SAH) product is coupled NAD(P)H oxidation through three enzyme reactions including glutamate dehydrogenase leading to absorbance changes at 340 nm. The utility and versatility of this assay is demonstrated for SET7/9 and SETD6 with peptides and full length protein substrates and for M.HaeIII with a DNA substrate. CONCLUSIONS This study shows a simple and robust assay for the continuous monitoring of MT enzymatic activity. This assay can be used for the determination of steady-state kinetic enzymatic parameters (e.g., k cat and K M) for a wide variety of MTs and can be easily adapted for high-throughput detection of MT activity for various applications.
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Affiliation(s)
- Shai Duchin
- Departments of Life Sciences, Ben-Gurion University of the Negev, 84105 Be'er Sheva, Israel.,The National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, 84105 Be'er Sheva, Israel
| | - Zlata Vershinin
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Ben-Gurion University of the Negev, 84105 Be'er Sheva, Israel.,The National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, 84105 Be'er Sheva, Israel
| | - Dan Levy
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Ben-Gurion University of the Negev, 84105 Be'er Sheva, Israel.,The National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, 84105 Be'er Sheva, Israel
| | - Amir Aharoni
- Departments of Life Sciences, Ben-Gurion University of the Negev, 84105 Be'er Sheva, Israel.,The National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, 84105 Be'er Sheva, Israel
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12
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Ma H, Howitz KT, Horiuchi KY, Wang Y. Histone Methyltransferase Activity Assays. EPIGENETICS FOR DRUG DISCOVERY 2015. [DOI: 10.1039/9781782628484-00267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Histone methyltransferases (HMTs) methylate either the lysine or arginine residues on histones and other proteins and play a crucial role in epigenetic regulation. Over 70 HMTs are encoded by the human genome, and many have been implicated in the aetiology of cancer, inflammatory diseases, neurodegenerative diseases and other conditions. There are currently about a dozen HMT activity assays available, and many of these assay formats are applicable to other epigenetic factors, such as histone acetyltransferases, histone deacetylases, and histone and DNA demethylases. Many factors need to be considered in selecting an HMT assay for drug discovery studies, including cost, adaptability to high-throughput screening, and rates of false positives and false negatives. This chapter describes the mechanisms of the major assay platforms available for HMT screening and profiling and presents the advantages and limitations associated with each.
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Affiliation(s)
- Haiching Ma
- Reaction Biology Corporation One Great Valley Parkway, Suite 2 Malvern PA 19355 USA
| | - Konrad T. Howitz
- Reaction Biology Corporation One Great Valley Parkway, Suite 2 Malvern PA 19355 USA
| | - Kurumi Y. Horiuchi
- Reaction Biology Corporation One Great Valley Parkway, Suite 2 Malvern PA 19355 USA
| | - Yuren Wang
- Reaction Biology Corporation One Great Valley Parkway, Suite 2 Malvern PA 19355 USA
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13
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Martinez NJ, Simeonov A. Cell-based assays to support the profiling of small molecules with histone methyltransferase and demethylase modulatory activity. DRUG DISCOVERY TODAY. TECHNOLOGIES 2015; 18:9-17. [PMID: 26723887 DOI: 10.1016/j.ddtec.2015.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/07/2015] [Indexed: 02/07/2023]
Abstract
Histone methylation is a prevalent and dynamic chromatin modification, executed by the action of histone methyltransferases (HMTs) and demethylases (HDMs). Aberrant activity of many of these enzymes is associated with human disease, hence, there is a growing interest in identifying corresponding small molecule inhibitors with therapeutic potential. To date, most of the technologies supporting the identification of these inhibitors constitute in vitro biochemical assays which, although robust and sensitive, do not study HMTs and HDMs in their native cellular state nor provide information of inhibitor's cell permeability and toxicity. The evident need for complementary cellular approaches has recently propelled the development of cell-based assays that enable screening of HMT and HDM enzymes in a more relevant environment. Here, we highlight current cellular methodologies for HMT and HDM drug discovery support. We anticipate that implementation of these cell-based assays will positively impact the discovery of pharmacologically potent HMT and HDM inhibitors.
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Affiliation(s)
- Natalia J Martinez
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, United States
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, United States.
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14
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Luense S, Denner P, Fernández-Montalván A, Hartung I, Husemann M, Stresemann C, Prechtl S. Quantification of histone H3 Lys27 trimethylation (H3K27me3) by high-throughput microscopy enables cellular large-scale screening for small-molecule EZH2 inhibitors. ACTA ACUST UNITED AC 2014; 20:190-201. [PMID: 25409661 PMCID: PMC4361481 DOI: 10.1177/1087057114559668] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
EZH2 inhibition can decrease global histone H3 lysine 27 trimethylation (H3K27me3) and thereby reactivates silenced tumor suppressor genes. Inhibition of EZH2 is regarded as an option for therapeutic cancer intervention. To identify novel small-molecule (SMOL) inhibitors of EZH2 in drug discovery, trustworthy cellular assays amenable for phenotypic high-throughput screening (HTS) are crucial. We describe a reliable approach that quantifies changes in global levels of histone modification marks using high-content analysis (HCA). The approach was validated in different cell lines by using small interfering RNA and SMOL inhibitors. By automation and miniaturization from a 384-well to 1536-well plate, we demonstrated its utility in conducting phenotypic HTS campaigns and assessing structure-activity relationships (SAR). This assay enables screening of SMOL EZH2 inhibitors and can advance the mechanistic understanding of H3K27me3 suppression, which is crucial with regard to epigenetic therapy. We observed that a decrease in global H3K27me3, induced by EZH2 inhibition, comprises two distinct mechanisms: (1) inhibition of de novo DNA methylation and (II) inhibition of dynamic, replication-independent H3K27me3 turnover. This report describes an HCA assay for primary HTS to identify, profile, and optimize cellular active SMOL inhibitors targeting histone methyltransferases, which could benefit epigenetic drug discovery.
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Affiliation(s)
- Svenja Luense
- Lead Discovery Berlin-Screening, Global Drug Discovery, Bayer Pharma AG, Berlin, Germany
| | - Philip Denner
- Lead Discovery Berlin-Screening, Global Drug Discovery, Bayer Pharma AG, Berlin, Germany
| | | | - Ingo Hartung
- Department of Medicinal Chemistry Berlin, Medicinal Chemistry I, Microbiological Chemistry, Global Drug Discovery, Bayer Pharma AG, Berlin, Germany
| | - Manfred Husemann
- Lead Discovery Berlin-Screening, Global Drug Discovery, Bayer Pharma AG, Berlin, Germany
| | - Carlo Stresemann
- Department of Oncology, Chromatin Modulation and Oncogenomics, Global Drug Discovery, Bayer Pharma AG, Berlin, Germany
| | - Stefan Prechtl
- Lead Discovery Berlin-Screening, Global Drug Discovery, Bayer Pharma AG, Berlin, Germany
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15
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Hildebrandt N, Wegner KD, Algar WR. Luminescent terbium complexes: Superior Förster resonance energy transfer donors for flexible and sensitive multiplexed biosensing. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2014.01.020] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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Sandi C, Sandi M, Anjomani Virmouni S, Al-Mahdawi S, Pook MA. Epigenetic-based therapies for Friedreich ataxia. Front Genet 2014; 5:165. [PMID: 24917884 PMCID: PMC4042889 DOI: 10.3389/fgene.2014.00165] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 05/19/2014] [Indexed: 11/29/2022] Open
Abstract
Friedreich ataxia (FRDA) is a lethal autosomal recessive neurodegenerative disorder caused primarily by a homozygous GAA repeat expansion mutation within the first intron of the FXN gene, leading to inhibition of FXN transcription and thus reduced frataxin protein expression. Recent studies have shown that epigenetic marks, comprising chemical modifications of DNA and histones, are associated with FXN gene silencing. Such epigenetic marks can be reversed, making them suitable targets for epigenetic-based therapy. Furthermore, since FRDA is caused by insufficient, but functional, frataxin protein, epigenetic-based transcriptional re-activation of the FXN gene is an attractive therapeutic option. In this review we summarize our current understanding of the epigenetic basis of FXN gene silencing and we discuss current epigenetic-based FRDA therapeutic strategies.
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Affiliation(s)
| | | | | | | | - Mark A. Pook
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University LondonUxbridge, UK
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17
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Schutkowski M, Fischer F, Roessler C, Steegborn C. New assays and approaches for discovery and design of Sirtuin modulators. Expert Opin Drug Discov 2014; 9:183-99. [DOI: 10.1517/17460441.2014.875526] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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18
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Qian J, Lu L, Wu J, Ma H. Development of multiple cell-based assays for the detection of histone H3 Lys27 trimethylation (H3K27me3). Assay Drug Dev Technol 2013; 11:449-56. [PMID: 23992119 DOI: 10.1089/adt.2013.515] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Posttranslational modification of histone proteins in eukaryotes plays an important role in gene transcription and chromatin structure. Dysregulation of the enzymes involved in histone modification has been linked to many cancer forms, making this target class a potential new area for therapeutics. A reliable assay to monitor small-molecule inhibition of various epigenetic enzymes should play a critical role in drug discovery to fight cancer. However, it has been challenging to develop cell-based assays for high-throughput screening (HTS) and compound profiling. Recently, two homogeneous cell-based assay kits using the AlphaLISA(®) and LanthaScreen(®) technologies to detect trimethyl histone H3 Lysine 27 have become commercially available, and a heterogeneous cell assay with modified dissociation-enhanced lanthanide fluorescence immunoassay (DELFIA(®)) format has been reported. To compare their pros and cons, we evaluated, optimized, and validated these three assay formats in three different cell lines and compared their activities with traditional Western blot detection of histone methylation inhibition by using commercial and in-house small-molecule inhibitors. Our data indicate that, although all four formats produced acceptable results, the homogeneous AlphaLISA assay was best suited for HTS and compound profiling due to its wider window and ease of automation. The DELFIA and Western blot assays were useful as validation tools to confirm the cell activities and eliminate potential false-positive compounds.
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Affiliation(s)
- Jie Qian
- Reaction Biology Corp., Malvern, Pennsylvania
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19
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Zeng H, Wu J, Bedford MT, Sbardella G, Hoffmann FM, Bi K, Xu W. A TR-FRET-based functional assay for screening activators of CARM1. Chembiochem 2013; 14:827-35. [PMID: 23585185 PMCID: PMC3828750 DOI: 10.1002/cbic.201300029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Indexed: 11/07/2022]
Abstract
Epigenetics is an emerging field that demands selective cell-permeable chemical probes to perturb, especially in vivo, the activity of specific enzymes involved in modulating the epigenetic codes. Coactivator-associated arginine methyltransferase 1 (CARM1) is a coactivator of estrogen receptor α (ERα), the main target in human breast cancer. We previously showed that twofold overexpression of CARM1 in MCF7 breast cancer cells increased the expression of ERα-target genes involved in differentiation and reduced cell proliferation, thus leading to the hypothesis that activating CARM1 by chemical activators might be therapeutically effective in breast cancer. Selective, potent, cell-permeable CARM1 activators will be essential to test this hypothesis. Here we report the development of a cell-based, time-resolved (TR) FRET assay that uses poly(A) binding protein 1 (PABP1) methylation to monitor cellular activity of CARM1. The LanthaScreen TR-FRET assay uses MCF7 cells expressing GFP-PABP1 fusion protein through BacMam gene delivery system, methyl-PABP1 specific antibody, and terbium-labeled secondary antibody. This assay has been validated as reflecting the expression and/or activity of CARM1 and optimized for high throughput screening to identify CARM1 allosteric activators. This TR-FRET platform serves as a generic tool for functional screening of cell-permeable, chemical modulators of CARM1 for elucidation of its in vivo functions.
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Affiliation(s)
- Hao Zeng
- Graduate Program in Cellular and Molecular Biology, McArdle Laboratory for Cancer Research and Carbone Comprehensive Cancer Center, University of Wisconsin, 1400 University Ave, Madison, WI 53706, USA
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20
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Airenne KJ, Hu YC, Kost TA, Smith RH, Kotin RM, Ono C, Matsuura Y, Wang S, Ylä-Herttuala S. Baculovirus: an insect-derived vector for diverse gene transfer applications. Mol Ther 2013; 21:739-49. [PMID: 23439502 PMCID: PMC3616530 DOI: 10.1038/mt.2012.286] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 12/11/2012] [Indexed: 01/23/2023] Open
Abstract
Insect-derived baculoviruses have emerged as versatile and safe workhorses of biotechnology. Baculovirus expression vectors (BEVs) have been applied widely for crop and forest protection, as well as safe tools for recombinant protein production in insect cells. However, BEVs ability to efficiently transduce noninsect cells is still relatively poorly recognized despite the fact that efficient baculovirus-mediated in vitro and ex vivo gene delivery into dormant and dividing vertebrate cells of diverse origin has been described convincingly by many authors. Preliminary proof of therapeutic potential has also been established in preclinical studies. This review summarizes the advantages and current status of baculovirus-mediated gene delivery. Stem cell transduction, preclinical animal studies, tissue engineering, vaccination, cancer gene therapy, viral vector production, and drug discovery are covered.
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Affiliation(s)
- Kari J Airenne
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Yu-Chen Hu
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Thomas A Kost
- Biological Reagents and Assay Development, GlaxoSmithKline R&D, Research Triangle Park, North Carolina, USA
| | - Richard H Smith
- Molecular Virology and Gene Therapy Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert M Kotin
- Molecular Virology and Gene Therapy Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Chikako Ono
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Yoshiharu Matsuura
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Shu Wang
- Institute of Bioengineering and Nanotechnology, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Seppo Ylä-Herttuala
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
- Research Unit, Kuopio University Hospital, Kuopio, Finland
- Gene Therapy Unit, Kuopio University Hospital, Kuopio, Finland
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21
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Hancock MK, Hermanson SB, Dolman NJ. A quantitative TR-FRET plate reader immunoassay for measuring autophagy. Autophagy 2012; 8:1227-44. [PMID: 22622129 DOI: 10.4161/auto.20441] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Autophagy involves the isolation and targeting of unwanted cellular components to lysosomes for their digestion and reuse. Autophagic dysregulation has recently been implicated in a wide range of disease processes, yet facile methods for quantifying autophagy have been lacking in the field. Here we describe the generation of a quantitative plate reader assay for measuring the autophagic activity of cells. One of the best characterized autophagy markers is the protein LC3B, which normally resides in the cytosol (LC3B-I) but upon induction of autophagy becomes lipidated and embedded in autophagosomal membranes (LC3B-II). To quantify autophagy, we reasoned that GFP-tagged LC3B could serve as a time-resolved fluorescence resonance energy transfer (TR-FRET) acceptor upon cell lysis in the presence of terbium-labeled LC3B antibodies. Using this TR-FRET immunoassay approach, we screened a panel of LC3B antibodies and identified an antibody that exhibits strong preferential affinity toward autophagosome-associated LC3B-II and thereby facilitates specific detection of autophagic activity. The plate reader format provides both a quantitative and an objective result, thus overcoming some of the key limitations of the traditional immunoblotting and imaging approaches used to monitor autophagy. Moreover, since the assay step requires only a single addition of cell lysis buffer containing the detection antibody its simple workflow is both automation-friendly and scalable, which renders it suitable for high-throughput screening. We demonstrate how this TR-FRET immunoassay for GFP-tagged LC3B-II can be applied to quantitatively detect changes in the autophagy activity of cells, including estimating effects on autophagic flux.
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Affiliation(s)
- Michael K Hancock
- Discovery & ADMET-TOX Systems--Life Technologies Corporation, Madison, WI, USA.
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22
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Luo M. Current chemical biology approaches to interrogate protein methyltransferases. ACS Chem Biol 2012; 7:443-63. [PMID: 22220966 DOI: 10.1021/cb200519y] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Protein methyltransferases (PMTs) play various physiological and pathological roles through methylating histone and nonhistone targets. However, most PMTs including more than 60 human PMTs remain to be fully characterized. The current approaches to elucidate the functions of PMTs have been diversified by many emerging chemical biology technologies. This review focuses on progress in these aspects and is organized into four discussion modules (assays, substrates, cofactors, and inhibitors) that are important to elucidate biological functions of PMTs. These modules are expected to provide general guidance and present emerging methods for researchers to select and combine suitable PMT-activity assays, well-defined substrates, novel SAM surrogates, and PMT inhibitors to interrogate PMTs.
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Affiliation(s)
- Minkui Luo
- Molecular Pharmacology
and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New
York 10065, United States
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