1
|
Tian GL, Hsieh CJ, Taylor M, Lee JY, Luedtke RR, Mach RH. Design and Synthesis of D 3R Bitopic Ligands with Flexible Secondary Binding Fragments: Radioligand Binding and Computational Chemistry Studies. Molecules 2023; 29:123. [PMID: 38202706 PMCID: PMC10779535 DOI: 10.3390/molecules29010123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
A series of bitopic ligands based on Fallypride with a flexible secondary binding fragment (SBF) were prepared with the goal of preparing a D3R-selective compound. The effect of the flexible linker ((R,S)-trans-2a-d), SBFs ((R,S)-trans-2h-j), and the chirality of orthosteric binding fragments (OBFs) ((S,R)-trans-d, (S,R)-trans-i, (S,S)-trans-d, (S,S)-trans-i, (R,R)-trans-d, and (R,R)-trans-i) were evaluated in in vitro binding assays. Computational chemistry studies revealed that the interaction of the fragment binding to the SBF increased the distance between the pyrrolidine nitrogen and ASP1103.32 of the D3R, thereby reducing the D3R affinity to a suboptimal level.
Collapse
Affiliation(s)
- Gui-Long Tian
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (G.-L.T.); (C.-J.H.)
| | - Chia-Ju Hsieh
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (G.-L.T.); (C.-J.H.)
| | - Michelle Taylor
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; (M.T.)
| | - Ji Youn Lee
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (G.-L.T.); (C.-J.H.)
| | - Robert R. Luedtke
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; (M.T.)
| | - Robert H. Mach
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (G.-L.T.); (C.-J.H.)
| |
Collapse
|
2
|
Hsieh CJ, Giannakoulias S, Petersson EJ, Mach RH. Computational Chemistry for the Identification of Lead Compounds for Radiotracer Development. Pharmaceuticals (Basel) 2023; 16:317. [PMID: 37259459 PMCID: PMC9964981 DOI: 10.3390/ph16020317] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 11/19/2023] Open
Abstract
The use of computer-aided drug design (CADD) for the identification of lead compounds in radiotracer development is steadily increasing. Traditional CADD methods, such as structure-based and ligand-based virtual screening and optimization, have been successfully utilized in many drug discovery programs and are highlighted throughout this review. First, we discuss the use of virtual screening for hit identification at the beginning of drug discovery programs. This is followed by an analysis of how the hits derived from virtual screening can be filtered and culled to highly probable candidates to test in in vitro assays. We then illustrate how CADD can be used to optimize the potency of experimentally validated hit compounds from virtual screening for use in positron emission tomography (PET). Finally, we conclude with a survey of the newest techniques in CADD employing machine learning (ML).
Collapse
Affiliation(s)
- Chia-Ju Hsieh
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sam Giannakoulias
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - E. James Petersson
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert H. Mach
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
3
|
Juza R, Musilek K, Mezeiova E, Soukup O, Korabecny J. Recent advances in dopamine D 2 receptor ligands in the treatment of neuropsychiatric disorders. Med Res Rev 2023; 43:55-211. [PMID: 36111795 DOI: 10.1002/med.21923] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 07/29/2022] [Accepted: 08/09/2022] [Indexed: 02/04/2023]
Abstract
Dopamine is a biologically active amine synthesized in the central and peripheral nervous system. This biogenic monoamine acts by activating five types of dopamine receptors (D1-5 Rs), which belong to the G protein-coupled receptor family. Antagonists and partial agonists of D2 Rs are used to treat schizophrenia, Parkinson's disease, depression, and anxiety. The typical pharmacophore with high D2 R affinity comprises four main areas, namely aromatic moiety, cyclic amine, central linker and aromatic/heteroaromatic lipophilic fragment. From the literature reviewed herein, we can conclude that 4-(2,3-dichlorophenyl), 4-(2-methoxyphenyl)-, 4-(benzo[b]thiophen-4-yl)-1-substituted piperazine, and 4-(6-fluorobenzo[d]isoxazol-3-yl)piperidine moieties are critical for high D2 R affinity. Four to six atoms chains are optimal for D2 R affinity with 4-butoxyl as the most pronounced one. The bicyclic aromatic/heteroaromatic systems are most frequently occurring as lipophilic appendages to retain high D2 R affinity. In this review, we provide a thorough overview of the therapeutic potential of D2 R modulators in the treatment of the aforementioned disorders. In addition, this review summarizes current knowledge about these diseases, with a focus on the dopaminergic pathway underlying these pathologies. Major attention is paid to the structure, function, and pharmacology of novel D2 R ligands, which have been developed in the last decade (2010-2021), and belong to the 1,4-disubstituted aromatic cyclic amine group. Due to the abundance of data, allosteric D2 R ligands and D2 R modulators from patents are not discussed in this review.
Collapse
Affiliation(s)
- Radomir Juza
- Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic.,Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Kamil Musilek
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic.,Biomedical Research Centre, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| | - Eva Mezeiova
- Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic.,Biomedical Research Centre, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| | - Ondrej Soukup
- Biomedical Research Centre, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| | - Jan Korabecny
- Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic.,Biomedical Research Centre, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| |
Collapse
|
4
|
Kim HY, Lee JY, Hsieh CJ, Taylor M, Luedtke RR, Mach RH. Design and Synthesis of Conformationally Flexible Scaffold as Bitopic Ligands for Potent D 3-Selective Antagonists. Int J Mol Sci 2022; 24:ijms24010432. [PMID: 36613875 PMCID: PMC9820167 DOI: 10.3390/ijms24010432] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/22/2022] [Accepted: 12/24/2022] [Indexed: 12/28/2022] Open
Abstract
Previous studies have confirmed that the binding of D3 receptor antagonists is competitively inhibited by endogenous dopamine despite excellent binding affinity for D3 receptors. This result urges the development of an alternative scaffold that is capable of competing with dopamine for binding to the D3 receptor. Herein, an SAR study was conducted on metoclopramide that incorporated a flexible scaffold for interaction with the secondary binding site of the D3 receptor. The alteration of benzamide substituents and secondary binding fragments with aryl carboxamides resulted in excellent D3 receptor affinities (Ki = 0.8-13.2 nM) with subtype selectivity to the D2 receptor ranging from 22- to 180-fold. The β-arrestin recruitment assay revealed that 21c with 4-(pyridine-4-yl)benzamide can compete well against dopamine with the highest potency (IC50 = 1.3 nM). Computational studies demonstrated that the high potency of 21c and its analogs was the result of interactions with the secondary binding site of the D3 receptor. These compounds also displayed minimal effects for other GPCRs except moderate affinity for 5-HT3 receptors and TSPO. The results of this study revealed that a new class of selective D3 receptor antagonists should be useful in behavioral pharmacology studies and as lead compounds for PET radiotracer development.
Collapse
Affiliation(s)
- Ho Young Kim
- Vagelos Laboratories, Department of Radiology, University of Pennsylvania, 1012, 231 S. 34th Street, Philadelphia, PA 19104, USA
| | - Ji Youn Lee
- Vagelos Laboratories, Department of Radiology, University of Pennsylvania, 1012, 231 S. 34th Street, Philadelphia, PA 19104, USA
| | - Chia-Ju Hsieh
- Vagelos Laboratories, Department of Radiology, University of Pennsylvania, 1012, 231 S. 34th Street, Philadelphia, PA 19104, USA
| | - Michelle Taylor
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Robert R. Luedtke
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Robert H. Mach
- Vagelos Laboratories, Department of Radiology, University of Pennsylvania, 1012, 231 S. 34th Street, Philadelphia, PA 19104, USA
- Correspondence:
| |
Collapse
|
5
|
Blass BE, Chen PJ, Taylor M, Griffin SA, Gordon JC, Luedtke RR. Design, synthesis, and evaluation of functionalized 5-(4-arylpiperazin-1-yl)-N-quinolinyl-pentanamides as selective dopamine D3 receptor ligands. Med Chem Res 2022. [DOI: 10.1007/s00044-022-02873-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
6
|
Synthesis of functionalized 5-(4-arylpiperazin-1-yl)-N-arylpentanamides and their evaluation as D3 receptor ligands. Med Chem Res 2022. [DOI: 10.1007/s00044-022-02872-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
7
|
Jiao X, Xing Y, Wang H, Jin X, Zhang T, Peng X, Li R, Liang L, Liu R, Han L, Li Z. A strategy based on gene sequencing and molecular docking for analysis and prediction of bioactive peptides in Shuxuetong injection. Biophys Chem 2021; 282:106749. [PMID: 34971853 DOI: 10.1016/j.bpc.2021.106749] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/19/2021] [Accepted: 12/21/2021] [Indexed: 12/15/2022]
Abstract
Peptides are a class of protein fragments with relatively high biological activity and intense specificity, which play crucial role in the treatment of Shuxuetong injection (SXT). However, the extraordinary complexity of Chinese medicinal formulates and the lack of systematic identification methods are primary challenges for study of pharmacodynamic peptides. In addition, infinitesimal peptides contents further hinder the identification and structural characterization of polypeptide by traditional means. In this paper, we described a strategy that LC-MS combined with molecular docking to systematically illustrate the peptide components of SXT. The key to this research was used of gene sequencing to establish a SXT protein database to further achieve the separation and enrichment of chemical methods. Moreover, the ADRA2A, PAR4 and DRD3 were precisely docked with the identified peptides. The result indicated that 12 compounds had stable binding ability and were speculated to be the latent bioactive monomers for the treatment of stroke. Additionally, 12 peptides were verified by cell-based experiment. The results showed that only YLKTT could indeed protect astrocytes from oxygen glucose deprivation/reoxygenation (OGD/R). The YLKTT showed higher activity than the others in vitro. It might be a completely new compound that has never been reported before, providing the basis for further research and a new paradigm for stroke.
Collapse
Affiliation(s)
- Xinyi Jiao
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Yanchao Xing
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Haitao Wang
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Xin Jin
- Military Medicine Section, Logistics University of Chinese People's Armed Police Force, 1 Huizhihuan Road, Dongli District, Tianjin 300309, China
| | - Tingting Zhang
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Xingru Peng
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Rui Li
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Liuyi Liang
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Rui Liu
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China.
| | - Lifeng Han
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China.
| | - Zheng Li
- State Key Laboratory of Component-based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, 10 Poyang Lake Road, West Zone of Tuanbo New City, Jinghai District, Tianjin 301617, China.
| |
Collapse
|
8
|
Blass BE, Chen PJ, Taylor M, Griffin SA, Gordon JC, Luedtke RR. Design, synthesis, and evaluation of functionalized 5-(4-arylpiperazin-1-yl)-N-arylpentanamides as selective dopamine D3 receptor ligands. Med Chem Res 2021. [DOI: 10.1007/s00044-021-02825-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
9
|
The Structural Determinants for α 1-Adrenergic/Serotonin Receptors Activity among Phenylpiperazine-Hydantoin Derivatives. Molecules 2021; 26:molecules26227025. [PMID: 34834117 PMCID: PMC8623851 DOI: 10.3390/molecules26227025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 12/26/2022] Open
Abstract
Several studies confirmed the reciprocal interactions between adrenergic and serotoninergic systems and the influence of these phenomena on the pathogenesis of anxiety. Hence, searching for chemical agents with a multifunctional pharmacodynamic profile may bring highly effective therapy for CNS disorders. This study presents a deep structural insight into the hydantoin-arylpiperazine group and their serotonin/α-adrenergic activity. The newly synthesized compounds were tested in the radioligand binding assay and the intrinsic activity was evaluated for the selected derivatives. The computer-aided SAR analysis enabled us to answer questions about the influence of particular structural fragments on selective vs. multifunctional activity. As a result of the performed investigations, there were two leading structures: (a) compound 12 with multifunctional adrenergic-serotonin activity, which is a promising candidate to be an effective anxiolytic agent; (b) compound 14 with high α1A/α1D affinity and selectivity towards α1B, which is recommended due to the elimination of probable cardiotoxic effect. The structural conclusions of this work provide significant support for future lead optimization in order to achieve the desired pharmacodynamic profile in searching for new CNS-modulating agents.
Collapse
|
10
|
Lee B, Taylor M, Griffin SA, McInnis T, Sumien N, Mach RH, Luedtke RR. Evaluation of Substituted N-Phenylpiperazine Analogs as D3 vs. D2 Dopamine Receptor Subtype Selective Ligands. Molecules 2021; 26:molecules26113182. [PMID: 34073405 PMCID: PMC8198181 DOI: 10.3390/molecules26113182] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 11/20/2022] Open
Abstract
N-phenylpiperazine analogs can bind selectively to the D3 versus the D2 dopamine receptor subtype despite the fact that these two D2-like dopamine receptor subtypes exhibit substantial amino acid sequence homology. The binding for a number of these receptor subtype selective compounds was found to be consistent with their ability to bind at the D3 dopamine receptor subtype in a bitopic manner. In this study, a series of the 3-thiophenephenyl and 4-thiazolylphenyl fluoride substituted N-phenylpiperazine analogs were evaluated. Compound 6a was found to bind at the human D3 receptor with nanomolar affinity with substantial D3 vs. D2 binding selectivity (approximately 500-fold). Compound 6a was also tested for activity in two in-vivo assays: (1) a hallucinogenic-dependent head twitch response inhibition assay using DBA/2J mice and (2) an L-dopa-dependent abnormal involuntary movement (AIM) inhibition assay using unilateral 6-hydroxydopamine lesioned (hemiparkinsonian) rats. Compound 6a was found to be active in both assays. This compound could lead to a better understanding of how a bitopic D3 dopamine receptor selective ligand might lead to the development of pharmacotherapeutics for the treatment of levodopa-induced dyskinesia (LID) in patients with Parkinson’s disease.
Collapse
Affiliation(s)
- Boeun Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (B.L.); (R.H.M.)
| | - Michelle Taylor
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center-Fort Worth, Fort Worth, TX 76107, USA; (M.T.); (S.A.G.); (T.M.); (N.S.)
| | - Suzy A. Griffin
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center-Fort Worth, Fort Worth, TX 76107, USA; (M.T.); (S.A.G.); (T.M.); (N.S.)
| | - Tamara McInnis
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center-Fort Worth, Fort Worth, TX 76107, USA; (M.T.); (S.A.G.); (T.M.); (N.S.)
| | - Nathalie Sumien
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center-Fort Worth, Fort Worth, TX 76107, USA; (M.T.); (S.A.G.); (T.M.); (N.S.)
| | - Robert H. Mach
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (B.L.); (R.H.M.)
| | - Robert R. Luedtke
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center-Fort Worth, Fort Worth, TX 76107, USA; (M.T.); (S.A.G.); (T.M.); (N.S.)
- Correspondence:
| |
Collapse
|
11
|
Hayatshahi HS, Luedtke RR, Taylor M, Chen PJ, Blass BE, Liu J. Factors Governing Selectivity of Dopamine Receptor Binding Compounds for D2R and D3R Subtypes. J Chem Inf Model 2021; 61:2829-2843. [PMID: 33988991 DOI: 10.1021/acs.jcim.1c00036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Targeting the D3 dopamine receptor (D3R) is a promising pharmacotherapeutic strategy for the treatment of many disorders. The structure of the D3R is similar to the D2 dopamine receptor (D2R), especially in the transmembrane spanning regions that form the orthosteric binding site, making it difficult to identify D3R selective pharmacotherapeutic agents. Here, we examine the molecular basis for the high affinity D3R binding and D3R vs D2R binding selectivity of substituted phenylpiperazine thiopheneamides. We show that removing the thiophenearylamide portion of the ligand consistently decreases the affinity of these ligands at D3R, while not affecting their affinity at the D2R. Our long (>10 μs) molecular dynamics simulations demonstrated that both dopamine receptor subtypes adopt two major conformations that we refer to as closed or open conformations, with D3R sampling the open conformation more frequently than D2R. The binding of ligands with conjoined orthosteric-allosteric binding moieties causes the closed conformation to populate more often in the trajectories. Also, significant differences were observed in the extracellular loops (ECL) of these two receptor subtypes leading to the identification of several residues that contribute differently to the ligand binding for the two receptors that could potentially contribute to ligand binding selectivity. Our observations also suggest that the displacement of ordered water in the binding pocket of D3R contributes to the affinity of the compounds containing an allosteric binding motif. These studies provide a better understanding of how a bitopic mode of engagement can determine ligands that bind selectively to D2 and D3 dopamine receptor subtypes.
Collapse
Affiliation(s)
- Hamed S Hayatshahi
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, Texas 76107, United States
| | - Robert R Luedtke
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, Texas 76107, United States
| | - Michelle Taylor
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, Texas 76107, United States
| | - Peng-Jen Chen
- Moulder Center for Drug Discovery Research, Department of Pharmaceutical Sciences, Temple University School of Pharmacy, 3307 North Broad Street, Philadelphia, Pennsylvania 19140, United States
| | - Benjamin E Blass
- Moulder Center for Drug Discovery Research, Department of Pharmaceutical Sciences, Temple University School of Pharmacy, 3307 North Broad Street, Philadelphia, Pennsylvania 19140, United States
| | - Jin Liu
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, Texas 76107, United States
| |
Collapse
|
12
|
Interaction of Ligands for PET with the Dopamine D3 Receptor: In Silico and In Vitro Methods. Biomolecules 2021; 11:biom11040529. [PMID: 33918451 PMCID: PMC8065765 DOI: 10.3390/biom11040529] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 12/28/2022] Open
Abstract
[18F]Fallypride and [18F]Fluortriopride (FTP) are two different PET radiotracers that bind with sub-nanomolar affinity to the dopamine D3 receptor (D3R). In spite of their similar D3 affinities, the two PET ligands display very different properties for labeling the D3R in vivo: [18F]Fallypride is capable of binding to D3R under "baseline" conditions, whereas [18F]FTP requires the depletion of synaptic dopamine in order to image the receptor in vivo. These data suggest that [18F]Fallypride is able to compete with synaptic dopamine for binding to the D3R, whereas [18F]FTP is not. The goal of this study was to conduct a series of docking and molecular dynamic simulation studies to identify differences in the ability of each molecule to interact with the D3R that could explain these differences with respect to competition with synaptic dopamine. Competition studies measuring the ability of each ligand to compete with dopamine in the β-arrestin assay were also conducted. The results of the in silico studies indicate that FTP has a weaker interaction with the orthosteric binding site of the D3R versus that of Fallypride. The results of the in silico studies were also consistent with the IC50 values of each compound in the dopamine β-arrestin competition assays. The results of this study indicate that in silico methods may be able to predict the ability of a small molecule to compete with synaptic dopamine for binding to the D3R.
Collapse
|
13
|
Gao X, Huang Z, Feng C, Guan C, Li R, Xie H, Chen J, Li M, Que R, Deng B, Cao P, Li M, Lu J, Huang Y, Li M, Yang W, Yang X, Wen C, Liang X, Yang Q, Chao YX, Chan LL, Yenari MA, Jin K, Chaudhuri KR, Zhang J, Tan EK, Wang Q. Multimodal analysis of gene expression from postmortem brains and blood identifies synaptic vesicle trafficking genes to be associated with Parkinson's disease. Brief Bioinform 2020; 22:5932213. [PMID: 33079984 DOI: 10.1093/bib/bbaa244] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/23/2020] [Accepted: 09/01/2020] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE We aimed to identify key susceptibility gene targets in multiple datasets generated from postmortem brains and blood of Parkinson's disease (PD) patients and healthy controls (HC). METHODS We performed a multitiered analysis to integrate the gene expression data using multiple-gene chips from 244 human postmortem tissues. We identified hub node genes in the highly PD-related consensus module by constructing protein-protein interaction (PPI) networks. Next, we validated the top four interacting genes in 238 subjects (90 sporadic PD, 125 HC and 23 Parkinson's Plus Syndrome (PPS)). Utilizing multinomial logistic regression analysis (MLRA) and receiver operating characteristic (ROC), we analyzed the risk factors and diagnostic power for discriminating PD from HC and PPS. RESULTS We identified 1333 genes that were significantly different between PD and HCs based on seven microarray datasets. The identified MEturquoise module is related to synaptic vesicle trafficking (SVT) dysfunction in PD (P < 0.05), and PPI analysis revealed that SVT genes PPP2CA, SYNJ1, NSF and PPP3CB were the top four hub node genes in MEturquoise (P < 0.001). The levels of these four genes in PD postmortem brains were lower than those in HC brains. We found lower blood levels of PPP2CA, SYNJ1 and NSF in PD compared with HC, and lower SYNJ1 in PD compared with PPS (P < 0.05). SYNJ1, negatively correlated to PD severity, displayed an excellent power to discriminating PD from HC and PPS. CONCLUSIONS This study highlights that SVT genes, especially SYNJ1, may be promising markers in discriminating PD from HCs and PPS.
Collapse
Affiliation(s)
- Xiaoya Gao
- Department of Neurology, Zhujiang Hospital, Southern Medical University, China
| | - Zifeng Huang
- Department of Neurology, Zhujiang Hospital of Southern Medical University, China
| | - Cailing Feng
- Department of Neurology, Zhujiang Hospital of Southern Medical University, China
| | - Chaohao Guan
- Department of Neurology, Zhujiang Hospital of Southern Medical University, China
| | - Ruidong Li
- Genetics, Genomics, and Bioinformatics Program, Department of Botany and Plant Sciences of University of California, USA
| | - Haiting Xie
- Department of Neurology of Zhujiang Hospital of Southern Medical University, China
| | - Jian Chen
- Department of Neurology of Zhujiang Hospital of Southern Medical University, China
| | - Mingchun Li
- Department of Neurology of Zhujiang Hospital of Southern Medical University, China
| | - Rongfang Que
- Department of Neurology, Zhujiang Hospital of Southern Medical University, China
| | - Bin Deng
- Department of Neurology of Zhujiang Hospital of Southern Medical University, China
| | - Peihua Cao
- Clinical Research Centre of Zhujiang Hospital of Southern Medical University, China
| | - Mengyan Li
- Department of Neurology of First Municipal Hospital of Guangzhou, China
| | - Jianjun Lu
- Laboratory for Neuromodulation of Guangdong Second Provincial General Hospital, China
| | - Yihong Huang
- Department of Neurology of Fifth Affiliated Hospital of Southern Medical University, China
| | - Minzi Li
- Department of Neurology, Zhujiang Hospital of Southern Medical University, Guanghzou, China
| | - Weihong Yang
- Department of Neurology, Zhujiang Hospital of Southern Medical University, China
| | - Xiaohua Yang
- Department of Neurology, Zhujiang Hospital of Southern Medical University, China
| | - Chunyan Wen
- Department of Neurology, Zhujiang Hospital of Southern Medical University, China
| | - Xiaomei Liang
- Department of Neurology, Zhujiang Hospital of Southern Medical University, China
| | - Qin Yang
- Department of Neurology of Zhujiang Hospital of Southern Medical University, China
| | - Yin-Xia Chao
- Department of Neurology of National Neuroscience Institute, Singapore General Hospital, Duke-NUS Medical School
| | - Ling-Ling Chan
- Department of Neurology of National Neuroscience Institute, Singapore General Hospital, Duke-NUS Medical School
| | | | - Kunlin Jin
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - K Ray Chaudhuri
- International Parkinson Foundation Centre of Excellence at Kings College Hospital and research director at Kings College Hospital, and Kings College, Denmark Hill, London, SE5 9RS UK
| | - Jing Zhang
- Department of Pathology, University of Washington School of Medicine (USA)
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute, Singapore General Hospital, and a professor in the Duke-NUS Medical School, Singapore
| | - Qing Wang
- Head of Department of Neurology, Zhujiang Hospital, Southern Medical University, China
| |
Collapse
|
14
|
Hayatshahi HS, Liu J. Filtering out Low-Affinity Bitropic Ligands for Dopamine Receptors Based on Ligand Conformation. ACS Chem Neurosci 2020; 11:2523-2527. [PMID: 32786308 DOI: 10.1021/acschemneuro.0c00263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We investigated the correlation between the conformations of a set of published 90 bitopic compounds on their affinity for two subtypes of the human dopamine receptor, D2R and D3R. Using molecular dynamics simulations, we showed that the compounds with large populations of compact conformation in the free solution are weak binders to both subtypes of the receptor. Our study provides a computational approach to quickly filter out low-affinity dopamine receptor ligands before their costly chemical synthesis.
Collapse
Affiliation(s)
- Hamed S. Hayatshahi
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Jin Liu
- Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| |
Collapse
|
15
|
Krohn KA, Vera DR. Concepts for design and analysis of receptor radiopharmaceuticals: The Receptor-Binding Radiotracers series of meetings provided the foundation. Nucl Med Biol 2020; 92:5-23. [PMID: 32331709 DOI: 10.1016/j.nucmedbio.2020.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/08/2020] [Indexed: 12/14/2022]
Abstract
A symposium at George Washington University on Receptor-Binding Radiotracers in 1980 and three follow-up meetings held at University of California, San Diego provided a forum for debating the critical concepts involved in the new field of designing and evaluating radiotracers for imaging receptors and transporters. This review is intended to educate young investigators who may be relatively new to receptor radiopharmaceutical development. Our anticipated audience includes researchers in basic pharmacology, radiochemistry, imaging technology and kinetic data analysis and how these disciplines have worked together to build our understanding of the human biology of transporters and receptor signaling in health and disease. We have chosen to focus on radiochemical design of a useful imaging agent and how design is coupled to analysis of data collected from dynamic imaging with that agent. Some pharmacology may be required for designing the imaging agent and some imaging physics may be important in optimizing the quality of data that is collected. However, the key to a successful imaging agent is matching the radiotracer to the target receptor and to analysis of the time-course data that is used to parse delivery from specific binding and subsequent metabolism or degradation. Properly designed imaging agents are providing critical information about human biology in health and disease as well as pharmacodynamic response to drug interventions. The review emphasizes some of the ideas that were controversial at the 1980 conference and chronicles with literature examples how they have resolved over the four decades of using radiotracers to study transporters and receptors in human subjects. These examples show that there are situations where a very small KD, i.e. high affinity, has the potential to yield an image that reflects blood flow more than receptor density. The examples also show that by combining two studies, one with high specific activity and a second with low specific activity injections one can unravel the pseudo-first order rate B'max into the true second-order rate constant, k3, and the unoccupied receptor density. The final section describes how mathematical methods first presented to the receptor-imaging community in 1980 are now being used to provide confidence in the analysis of kinetic biodistribution studies. Our hope is that by bringing these concepts together in a single review, the next generation of scientists developing receptor imaging agents can be much more efficient than their pioneers in developing useful imaging methods.
Collapse
Affiliation(s)
- Kenneth A Krohn
- Center for Radiochemistry Research, Department of Diagnostic Radiology, Mail Code L104, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, United States of America.
| | - David R Vera
- UCSD Moores Cancer Center, Department of Radiology, Mail Code 0819, University of California, San Diego, CA 92037, United States of America
| |
Collapse
|
16
|
Bashetti N, Shanmukha Kumar J, Seelam NV, Prasanna B, Mintz A, Damuka N, Devanathan S, Solingapuram Sai KK. One-pot synthesis of novel tert-butyl-4-substituted phenyl-1H-1,2,3-triazolo piperazine/piperidine carboxylates, potential GPR119 agonists. Bioorg Med Chem Lett 2019; 29:126707. [DOI: 10.1016/j.bmcl.2019.126707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/12/2019] [Accepted: 09/14/2019] [Indexed: 01/24/2023]
|
17
|
Shaik AB, Kumar V, Bonifazi A, Guerrero AM, Cemaj SL, Gadiano A, Lam J, Xi ZX, Rais R, Slusher BS, Newman AH. Investigation of Novel Primary and Secondary Pharmacophores and 3-Substitution in the Linking Chain of a Series of Highly Selective and Bitopic Dopamine D3 Receptor Antagonists and Partial Agonists. J Med Chem 2019; 62:9061-9077. [DOI: 10.1021/acs.jmedchem.9b00607] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Anver Basha Shaik
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Vivek Kumar
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Alessandro Bonifazi
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Adrian M. Guerrero
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Sophie L. Cemaj
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Alexandra Gadiano
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Jenny Lam
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Zheng-Xiong Xi
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Rana Rais
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Barbara S. Slusher
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Amy Hauck Newman
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse−Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| |
Collapse
|
18
|
Ribeiro JML, Filizola M. Insights From Molecular Dynamics Simulations of a Number of G-Protein Coupled Receptor Targets for the Treatment of Pain and Opioid Use Disorders. Front Mol Neurosci 2019; 12:207. [PMID: 31507375 PMCID: PMC6716474 DOI: 10.3389/fnmol.2019.00207] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/07/2019] [Indexed: 01/20/2023] Open
Abstract
Effective treatments for pain management remain elusive due to the dangerous side-effects of current gold-standard opioid analgesics, including the respiratory depression that has led to skyrocketing death rates from opioid overdoses over the past decade. In an attempt to address the horrific opioid crisis worldwide, the National Institute on Drug Abuse has recently proposed boosting research on specific pharmacological mechanisms mediated by a number of G protein-coupled receptors (GPCRs). This research is expected to expedite the discovery of medications for opioid overdose and opioid use disorders, leading toward a safer and more effective treatment of pain. Here, we review mechanistic insights from recent all-atom molecular dynamics simulations of a specific subset of GPCRs for which high-resolution experimental structures are available, including opioid, cannabinoid, orexin, metabotropic glutamate, and dopamine receptor subtypes.
Collapse
Affiliation(s)
- João Marcelo Lamim Ribeiro
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Marta Filizola
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| |
Collapse
|
19
|
Design, synthesis, and evaluation of N-(4-(4-phenyl piperazin-1-yl)butyl)-4-(thiophen-3-yl)benzamides as selective dopamine D 3 receptor ligands. Bioorg Med Chem Lett 2019; 29:2690-2694. [PMID: 31387791 DOI: 10.1016/j.bmcl.2019.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 11/20/2022]
Abstract
As part of our on-going effort to explore the role of dopamine receptors in drug addiction and identify potential novel therapies for this condition, we have a identified a series of N-(4-(4-phenyl piperazin-1-yl)butyl)-4-(thiophen-3-yl)benzamide D3 ligands. Members of this class are highly selective for D3 versus D2, and we have identified two compounds (13g and 13r) whose rat in vivo IV pharmacokinetic properties that indicate that they are suitable for assessment in in vivo efficacy models of substance use disorders.
Collapse
|
20
|
Reilly SW, Riad AA, Hsieh CJ, Sahlholm K, Jacome DA, Griffin S, Taylor M, Weng CC, Xu K, Kirschner N, Luedtke RR, Parry C, Malhotra S, Karanicolas J, Mach RH. Leveraging a Low-Affinity Diazaspiro Orthosteric Fragment to Reduce Dopamine D 3 Receptor (D 3R) Ligand Promiscuity across Highly Conserved Aminergic G-Protein-Coupled Receptors (GPCRs). J Med Chem 2019; 62:5132-5147. [PMID: 31021617 DOI: 10.1021/acs.jmedchem.9b00412] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Previously, we reported a 3-(2-methoxyphenyl)-9-(3-((4-methyl-5-phenyl-4 H-1,2,4-triazol-3-yl)thio)propyl)-3,9-diazaspiro[5.5]undecane (1) compound with excellent dopamine D3 receptor (D3R) affinity (D3R Ki = 12.0 nM) and selectivity (D2R/D3R ratio = 905). Herein, we present derivatives of 1 with comparable D3R affinity (32, D3R Ki = 3.2 nM, D2R/D3R ratio = 60) and selectivity (30, D3R Ki = 21.0 nM, D2R/D3R ratio = 934). Fragmentation of 1 revealed orthosteric fragment 5a to express an unusually low D3R affinity ( Ki = 2.7 μM). Compared to piperazine congener 31, which retains a high-affinity orthosteric fragment (5d, D3R Ki = 23.9 nM), 1 was found to be more selective for the D3R among D1- and D2-like receptors and exhibited negligible off-target interactions at serotoninergic and adrenergic G-protein-coupled receptors (GPCRs), common off-target sites for piperazine-containing D3R scaffolds. This study provides a unique rationale for implementing weakly potent orthosteric fragments into D3R ligand systems to minimize drug promiscuity at other aminergic GPCR sites.
Collapse
Affiliation(s)
- Sean W Reilly
- Department of Radiology , Perelman School of Medicine, University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Aladdin A Riad
- Department of Radiology , Perelman School of Medicine, University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Chia-Ju Hsieh
- Department of Radiology , Perelman School of Medicine, University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Kristoffer Sahlholm
- Department of Radiology , Perelman School of Medicine, University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Daniel A Jacome
- Department of Systems Pharmacology and Translational Therapeutics , University of Pennsylvania , 421 Curie Boulevard , Philadelphia , Pennsylvania 19104 , United States
| | - Suzy Griffin
- Department of Pharmacology and Neuroscience , University of North Texas Health Science Center , 3500 Camp Bowie Boulevard , Fort Worth , Texas 76107 , United States
| | - Michelle Taylor
- Department of Pharmacology and Neuroscience , University of North Texas Health Science Center , 3500 Camp Bowie Boulevard , Fort Worth , Texas 76107 , United States
| | - Chi-Chang Weng
- Department of Radiology , Perelman School of Medicine, University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Kuiying Xu
- Department of Radiology , Perelman School of Medicine, University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Nathan Kirschner
- Department of Radiology , Perelman School of Medicine, University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Robert R Luedtke
- Department of Pharmacology and Neuroscience , University of North Texas Health Science Center , 3500 Camp Bowie Boulevard , Fort Worth , Texas 76107 , United States
| | - Christopher Parry
- Program in Molecular Therapeutics , Fox Chase Cancer Center , 333 Cottman Avenue , Philadelphia , Pennsylvania 19111 , United States
| | - Shipra Malhotra
- Program in Molecular Therapeutics , Fox Chase Cancer Center , 333 Cottman Avenue , Philadelphia , Pennsylvania 19111 , United States
| | - John Karanicolas
- Program in Molecular Therapeutics , Fox Chase Cancer Center , 333 Cottman Avenue , Philadelphia , Pennsylvania 19111 , United States
| | - Robert H Mach
- Department of Radiology , Perelman School of Medicine, University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| |
Collapse
|