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Newton SR, Sobus JR, Ulrich EM, Singh RR, Chao A, McCord J, Laughlin-Toth S, Strynar M. Examining NTA performance and potential using fortified and reference house dust as part of EPA's Non-Targeted Analysis Collaborative Trial (ENTACT). Anal Bioanal Chem 2020; 412:4221-4233. [PMID: 32335688 DOI: 10.1007/s00216-020-02658-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/30/2020] [Accepted: 04/09/2020] [Indexed: 11/29/2022]
Abstract
Non-targeted analysis (NTA) methods are being increasingly used to aid in the identification of unknown compounds in the environment, a problem that has challenged environmental chemists for decades. Despite its increased use, quality assurance practices for NTA have not been well established. Furthermore, capabilities and limitations of certain NTA methods have not been thoroughly evaluated. Standard reference material dust (SRM 2585) was used here to evaluate the ability of NTA to identify previously reported compounds, as well as a suite of 365 chemicals that were spiked at various stages of the analytical procedure. Analysis of the unaltered SRM 2585 extracts revealed that several previously reported compounds can be identified by NTA, and that correct identification was dependent on concentration. A manual inspection of unknown features in SRM 2585 revealed the presence of two chlorinated and fluorinated compounds in high abundance, likely precursors to perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS). A retrospective analysis of data from the American Healthy Homes Survey revealed that these compounds were present in 42% of sampled homes. Spiking the dust at various stages of sample preparation revealed losses from extraction, cleanup, and instrumental analysis; the log Kow for individual compounds influenced the overall recovery levels but no pattern could be discerned from the various degrees of interference that the matrix had on the ionization efficiency of the spiked chemicals. Analysis of the matrix-free chemical mixture at low, medium, and high concentrations led to more correct identifications than analysis at one, very high concentration. Varying the spiked amount and identifying reported compounds at known concentrations allowed an estimation of the lower limits of identification (LOIs) for NTA, analogous to limits of detection in targeted analysis. The LOIs were much lower than levels in dust that would be likely to cause bioactivity in humans, indicating that NTA is useful for identifying and monitoring compounds that may be of toxicological concern. Graphical abstract.
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Affiliation(s)
- Seth R Newton
- Center for Computational Toxicology and Exposure, Office of Research & Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA.
| | - Jon R Sobus
- Center for Computational Toxicology and Exposure, Office of Research & Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Elin M Ulrich
- Center for Computational Toxicology and Exposure, Office of Research & Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Randolph R Singh
- Oak Ridge Institute for Science and Education, Post-Doctoral Participant, National Exposure Research Laboratory, Office of Research & Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA.,Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, 4365, Esch-sur-Alzette, Luxembourg
| | - Alex Chao
- Oak Ridge Institute for Science and Education, Post-Doctoral Participant, National Exposure Research Laboratory, Office of Research & Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - James McCord
- Center for Environmental Measurement and Modeling, Office of Research & Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Sarah Laughlin-Toth
- Oak Ridge Institute for Science and Education, Post-Doctoral Participant, National Exposure Research Laboratory, Office of Research & Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA.,Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Mark Strynar
- Center for Environmental Measurement and Modeling, Office of Research & Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
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Carter EK, Laughlin-Toth S, Dodd T, Wilson WD, Ivanov I. Small molecule binders recognize DNA microstructural variations via an induced fit mechanism. Phys Chem Chem Phys 2019; 21:1841-1851. [PMID: 30629058 PMCID: PMC6497476 DOI: 10.1039/c8cp05537h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [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: 01/09/2023]
Abstract
Regulation of gene-expression by specific targeting of protein-nucleic acid interactions has been a long-standing goal in medicinal chemistry. Transcription factors are considered "undruggable" because they lack binding sites well suited for binding small-molecules. In order to overcome this obstacle, we are interested in designing small molecules that bind to the corresponding promoter sequences and either prevent or modulate transcription factor association via an allosteric mechanism. To achieve this, we must design small molecules that are both sequence-specific and able to target G/C base pair sites. A thorough understanding of the relationship between binding affinity and the structural aspects of the small molecule-DNA complex would greatly aid in rational design of such compounds. Here we present a comprehensive analysis of sequence-specific DNA association of a synthetic minor groove binder using long timescale molecular dynamics. We show how binding selectivity arises from a combination of structural factors. Our results provide a framework for the rational design and optimization of synthetic small molecules in order to improve site-specific targeting of DNA for therapeutic uses in the design of selective DNA binders targeting transcription regulation.
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Affiliation(s)
- E. Kathleen Carter
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
| | - Sarah Laughlin-Toth
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Thomas Dodd
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
| | - W. David Wilson
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
| | - Ivaylo Ivanov
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
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3
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Marchetti C, Zyner KG, Ohnmacht SA, Robson M, Haider SM, Morton JP, Marsico G, Vo T, Laughlin-Toth S, Ahmed AA, Di Vita G, Pazitna I, Gunaratnam M, Besser RJ, Andrade ACG, Diocou S, Pike JA, Tannahill D, Pedley RB, Evans TRJ, Wilson WD, Balasubramanian S, Neidle S. Targeting Multiple Effector Pathways in Pancreatic Ductal Adenocarcinoma with a G-Quadruplex-Binding Small Molecule. J Med Chem 2018; 61:2500-2517. [PMID: 29356532 PMCID: PMC5867665 DOI: 10.1021/acs.jmedchem.7b01781] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [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: 12/07/2017] [Indexed: 12/11/2022]
Abstract
Human pancreatic ductal adenocarcinoma (PDAC) involves the dysregulation of multiple signaling pathways. A novel approach to the treatment of PDAC is described, involving the targeting of cancer genes in PDAC pathways having over-representation of G-quadruplexes, using the trisubstituted naphthalene diimide quadruplex-binding compound 2,7-bis(3-morpholinopropyl)-4-((2-(pyrrolidin-1-yl)ethyl)amino)benzo[ lmn][3,8]phenanthroline-1,3,6,8(2 H,7 H)-tetraone (CM03). This compound has been designed by computer modeling, is a potent inhibitor of cell growth in PDAC cell lines, and has anticancer activity in PDAC models, with a superior profile compared to gemcitabine, a commonly used therapy. Whole-transcriptome RNA-seq methodology has been used to analyze the effects of this quadruplex-binding small molecule on global gene expression. This has revealed the down-regulation of a large number of genes, rich in putative quadruplex elements and involved in essential pathways of PDAC survival, metastasis, and drug resistance. The changes produced by CM03 represent a global response to the complexity of human PDAC and may be applicable to other currently hard-to-treat cancers.
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Affiliation(s)
- Chiara Marchetti
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Katherine G. Zyner
- Cancer
Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K.
| | - Stephan A. Ohnmacht
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Mathew Robson
- Cancer
Research UK Cancer Centre, UCL Cancer Institute, University College London, London WC1E 6BT, U.K.
| | - Shozeb M. Haider
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Jennifer P. Morton
- Cancer
Research UK, Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD U.K.
- Institute
of Cancer Sciences. University of Glasgow, Glasgow G12 8QQ, U.K.
| | - Giovanni Marsico
- Cancer
Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K.
| | - Tam Vo
- Department
of Chemistry and Center for Biotechnology and Drug Design, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - Sarah Laughlin-Toth
- Department
of Chemistry and Center for Biotechnology and Drug Design, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - Ahmed A. Ahmed
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Gloria Di Vita
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Ingrida Pazitna
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Mekala Gunaratnam
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Rachael J. Besser
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Ana C. G. Andrade
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
| | - Seckou Diocou
- UCL
Cancer Institute, University College London, London WC1E 6BT, U.K.
| | - Jeremy A. Pike
- Cancer
Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K.
| | - David Tannahill
- Cancer
Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K.
| | - R. Barbara Pedley
- UCL
Cancer Institute, University College London, London WC1E 6BT, U.K.
| | - T. R. Jeffry Evans
- Cancer
Research UK, Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD U.K.
- Institute
of Cancer Sciences. University of Glasgow, Glasgow G12 8QQ, U.K.
| | - W. David Wilson
- Department
of Chemistry and Center for Biotechnology and Drug Design, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - Shankar Balasubramanian
- Cancer
Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, U.K.
- Department
of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
- The
School of Clinical Medicine, University
of Cambridge, Cambridge CB2 0SP, U.K.
| | - Stephen Neidle
- UCL
School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, U.K.
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Laughlin-Toth S, Carter EK, Ivanov I, Wilson WD. DNA microstructure influences selective binding of small molecules designed to target mixed-site DNA sequences. Nucleic Acids Res 2017; 45:1297-1306. [PMID: 28180310 PMCID: PMC5388402 DOI: 10.1093/nar/gkw1232] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/18/2016] [Accepted: 11/23/2016] [Indexed: 12/18/2022] Open
Abstract
Specific targeting of protein–nucleic acid interactions is an area of current interest, for example, in the regulation of gene-expression. Most transcription factor proteins bind in the DNA major groove; however, we are interested in an approach using small molecules to target the minor groove to control expression by an allosteric mechanism. In an effort to broaden sequence recognition of DNA-targeted-small-molecules to include both A·T and G·C base pairs, we recently discovered that the heterocyclic diamidine, DB2277, forms a strong monomer complex with a DNA sequence containing 5΄-AAAGTTT-3΄. Competition mass spectrometry and surface plasmon resonance identified new monomer complexes, as well as unexpected binding of two DB2277 with certain sequences. Inherent microstructural differences within the experimental DNAs were identified through computational analyses to understand the molecular basis for recognition. These findings emphasize the critical nature of the DNA minor groove microstructure for sequence-specific recognition and offer new avenues to design synthetic small molecules for effective regulation of gene-expression.
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Affiliation(s)
- Sarah Laughlin-Toth
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
| | - E Kathleen Carter
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
| | - Ivaylo Ivanov
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
| | - W David Wilson
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
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5
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Pett L, Kiakos K, Satam V, Patil P, Laughlin-Toth S, Gregory M, Bowerman M, Olson K, Savagian M, Lee M, Lee M, Wilson WD, Hochhauser D, Hartley JA. Modulation of topoisomerase IIα expression and chemosensitivity through targeted inhibition of NF-Y:DNA binding by a diamino p-anisyl-benzimidazole (Hx) polyamide. Biochim Biophys Acta Gene Regul Mech 2017; 1860:617-629. [PMID: 27750031 PMCID: PMC5757371 DOI: 10.1016/j.bbagrm.2016.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 10/11/2016] [Accepted: 10/12/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND Sequence specific polyamide HxIP 1, targeted to the inverted CCAAT Box 2 (ICB2) on the topoisomerase IIα (topo IIα) promoter can inhibit NF-Y binding, re-induce gene expression and increase sensitivity to etoposide. To enhance biological activity, diamino-containing derivatives (HxI*P 2 and HxIP* 3) were synthesised incorporating an alkyl amino group at the N1-heterocyclic position of the imidazole/pyrrole. METHODS DNase I footprinting was used to evaluate DNA binding of the diamino Hx-polyamides, and their ability to disrupt the NF-Y:ICB2 interaction assessed using EMSAs. Topo IIα mRNA (RT-PCR) and protein (Immunoblotting) levels were measured following 18h polyamide treatment of confluent A549 cells. γH2AX was used as a marker for etoposide-induced DNA damage after pre-treatment with HxIP* 3 and cell viability was measured using Cell-Titer Glo®. RESULTS Introduction of the N1-alkyl amino group reduced selectivity for the target sequence 5'-TACGAT-3' on the topo IIα promoter, but increased DNA binding affinity. Confocal microscopy revealed both fluorescent diamino polyamides localised in the nucleus, yet HxI*P 2 was unable to disrupt the NF-Y:ICB2 interaction and showed no effect against the downregulation of topo IIα. In contrast, inhibition of NF-Y binding by HxIP* 3 stimulated dose-dependent (0.1-2μM) re-induction of topo IIα and potentiated cytotoxicity of topo II poisons by enhancing DNA damage. CONCLUSIONS Polyamide functionalisation at the N1-position offers a design strategy to improve drug-like properties. Dicationic HxIP* 3 increased topo IIα expression and chemosensitivity to topo II-targeting agents. GENERAL SIGNIFICANCE Pharmacological modulation of topo IIα expression has the potential to enhance cellular sensitivity to clinically-used anticancer therapeutics. This article is part of a Special Issue entitled: Nuclear Factor Y in Development and Disease, edited by Prof. Roberto Mantovani.
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Affiliation(s)
- Luke Pett
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London, WC1E 6BT, UK
| | - Konstantinos Kiakos
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London, WC1E 6BT, UK
| | - Vijay Satam
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Pravin Patil
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Sarah Laughlin-Toth
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Matthew Gregory
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Michael Bowerman
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Kevin Olson
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Mia Savagian
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Megan Lee
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Moses Lee
- Department of Chemistry, Hope College, Holland, MI 49423, United States; Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Daniel Hochhauser
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London, WC1E 6BT, UK
| | - John A Hartley
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London, WC1E 6BT, UK.
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