1
|
Walby GD, Gu Q, Yang H, Martin SF. Structure-Affinity relationships of novel σ 2R/TMEM97 ligands. Bioorg Chem 2024; 145:107191. [PMID: 38432153 DOI: 10.1016/j.bioorg.2024.107191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/24/2024] [Accepted: 02/06/2024] [Indexed: 03/05/2024]
Abstract
The sigma 2 receptor (σ2R), which was recently identified as the transmembrane protein 97 (TMEM97), is increasingly attracting interest as a possible therapeutic target for indications in neuroscience. Toward identifying novel modulators of σ2R/TMEM97, we prepared a collection of benzoxazocine, benzomorphan, and methanobenzazepine ligands related to the known bioactive norbenzomorphans DKR-1677, FEM-1689, and EES-1686 and determined their Ki values for σ2R/TMEM97 and the sigma 1 receptor (σ1R). The σ2R/TMEM97 binding affinities and selectivities relative to σ1R of these new benzoxazocine, benzomorphan, and methanobenzazepine analogs are lower, often significantly lower, than their respective norbenzomorphan counterparts, suggesting the spatial orientation of pharmacophoric substituents is critical for binding to the two proteins. The benzoxazocine, benzomorphan, and methanobenzazepine congeners of DKR-1677 and FEM-1689 tend to be weakly selective for σ2R/TMEM97 versus σ1R, whereas EES-1686 derivatives exhibit the greatest selectivity, suggesting the size and/or nature of the substituent on the nitrogen atom of the scaffold may be important for selectivity. Computational docking studies were performed for the 1S,5R-and 1R,5S-enantiomers of DKR-1677, FEM-1689, and EES-1686 and their benzoxazocine, benzomorphan, and methanobenzazepine counterparts. These computations predict that the protonated amino group of each ligand forms a highly conserved salt bridge and a H-bonding interaction with Asp29 as well as a cation-π interaction with Tyr150 of σ2R/TMEM97. These electrostatic interactions are major driving forces for binding to σ2R/TMEM97 and are similar, though not identical, for each ligand. Other interactions within the well-defined binding pocket also tend to be comparable, but there are some major differences in how the hydrophobic aryl groups of various ligands interact with the protein surface external to the binding pocket. Overall, these studies show that the orientations of aryl and N-substituents on the norbenzomorphan and related scaffolds are important determinants of binding affinity of σ2R/TMEM97 ligands, and small changes can have significant effects upon binding profiles.
Collapse
Affiliation(s)
- Grant D Walby
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, United States
| | - Qi Gu
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, United States
| | - Hongfen Yang
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, United States
| | - Stephen F Martin
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, United States.
| |
Collapse
|
2
|
Zhong LJ, Fan JH, Chen P, Huang PF, Xiong BQ, Tang KW, Liu Y. Recent advances in ring-opening of cyclobutanone oximes for capturing SO 2, CO or O 2via a radical process. Org Biomol Chem 2023; 22:10-24. [PMID: 38018531 DOI: 10.1039/d3ob01762a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Cyclobutanone oximes and their derivatives are pivotal core structural motifs in organic chemistry. Iminyl-radical-triggered C-C bond cleavage of cyclobutanone oximes delivers an efficient strategy to produce stable distal cyano-substituted alkyl radicals, which can capture SO2, CO or O2 to form cyanoalkylsulfonyl radicals, cyanoalkylcarbonyl radicals or cyanoalkoxyl radicals under mild conditions. In the past several years, cyanoalkylsulfonylation/cyanoalkylcarbonyaltion/cyanoalkoxylation has attracted a lot of interest. In this updated report, the strategies for trapping SO2, CO or O2via iminyl-radical-triggered ring-opening of cyclobutanone oximes are summarized.
Collapse
Affiliation(s)
- Long-Jin Zhong
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Jian-Hong Fan
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Pu Chen
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Peng-Fei Huang
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Bi-Quan Xiong
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Ke-Wen Tang
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Yu Liu
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| |
Collapse
|
3
|
He Y, Su Q, Zhao L, Zhang L, Yu L, Shi J. Historical perspectives and recent advances in small molecule ligands of selective/biased/multi-targeted μ/δ/κ opioid receptor (2019-2022). Bioorg Chem 2023; 141:106869. [PMID: 37797454 DOI: 10.1016/j.bioorg.2023.106869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 09/11/2023] [Accepted: 09/15/2023] [Indexed: 10/07/2023]
Abstract
The opioids have been used for more than a thousand years and are not only the most widely prescribed drugs for moderate to severe pain and acute pain, but also the preferred drugs. However, their non-analgesic effects, especially respiratory depression and potential addiction, are important factors that plague the safety of clinical use and are an urgent problem for pharmacological researchers to address. Current research on analgesic drugs has evolved into different directions: de-opioidization; application of pharmacogenomics to individualize the use of opioids; development of new opioids with less adverse effects. The development of new opioid drugs remains a hot research topic, and with the in-depth study of opioid receptors and intracellular signal transduction mechanisms, new research ideas have been provided for the development of new opioid analgesics with less side effects and stronger analgesic effects. The development of novel opioid drugs in turn includes selective opioid receptor ligands, biased opioid receptor ligands, and multi-target opioid receptor ligands and positive allosteric modulators (PAMs) or antagonists and the single compound as multi-targeted agnoists/antagonists for different receptors. PAMs strategies are also getting newer and are the current research hotspots, including the BMS series of compounds and others, which are extensive and beyond the scope of this review. This review mainly focuses on the selective/biased/multi-targeted MOR/DOR/KOR (mu opioid receptor/delta opioid receptor/kappa opioid receptor) small molecule ligands and involves some cryo-electron microscopy (cryoEM) and structure-based approaches as well as the single compound as multi-targeted agnoists/antagonists for different receptors from 2019 to 2022, including discovery history, activities in vitro and vivo, and clinical studies, in an attempt to provide ideas for the development of novel opioid analgesics with fewer side effects.
Collapse
Affiliation(s)
- Ye He
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China
| | - Qian Su
- Department of Health Management & Institute of Health Management, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, China
| | - Liyun Zhao
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China
| | - Lijuan Zhang
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China.
| | - Lu Yu
- Department of Respiratory Medicine, Sichuan Academy of Medical Sciences and Sichuan provincial People's Hospital, Chengdu, 610072, China.
| | - Jianyou Shi
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China; State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, Sichuan, China.
| |
Collapse
|
4
|
Costanzo G, Turnaturi R, Parenti C, Spoto S, Piana S, Dichiara M, Zagni C, Galambos AR, Essmat N, Marrazzo A, Amata E, Al-Khrasani M, Pasquinucci L. New Insights into the Opioid Analgesic Profile of cis-(-)- N-Normetazocine-derived Ligands. Molecules 2023; 28:4827. [PMID: 37375382 DOI: 10.3390/molecules28124827] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
In this work, we report on the in vitro and in vivo pharmacological properties of LP1 analogs to complete the series of structural modifications aimed to generate compounds with improved analgesia. To do that, the phenyl ring in the N-substituent of our lead compound LP1 was replaced by an electron-rich or electron-deficient ring and linked through a propanamide or butyramide spacer at the basic nitrogen of the (-)-cis-N-normetazocine skeleton. In radioligand binding assays, compounds 3 and 7 were found to display nanomolar binding affinity for the μ opioid receptor (MOR) (Ki = 5.96 ± 0.08 nM and 1.49 ± 0.24 nM, respectively). In the mouse vas deferens (MVD) assay, compound 3 showed an antagonist effect against DAMGO ([D-Ala2, N-MePhe4, Gly-ol]-enkephalin), a highly selective MOR prototype agonist, whereas compound 7 produced naloxone reversible effect at MOR. Moreover, compound 7, as potent as LP1 and DAMGO at MOR, was able to reduce thermal and inflammatory pain assessed by the mouse tail-flick test and rat paw pressure thresholds (PPTs) measured by a Randall-Selitto test.
Collapse
Affiliation(s)
- Giuliana Costanzo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy
| | - Rita Turnaturi
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Carmela Parenti
- Department of Drug and Health Sciences, Section of Pharmacology and Toxicology, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Salvatore Spoto
- Department of Drug and Health Sciences, Section of Pharmacology and Toxicology, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Silvia Piana
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Maria Dichiara
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Chiara Zagni
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Anna Rita Galambos
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary
| | - Nariman Essmat
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary
| | - Agostino Marrazzo
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Emanuele Amata
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Mahmoud Al-Khrasani
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary
| | - Lorella Pasquinucci
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| |
Collapse
|
5
|
Costanzo G, Patamia V, Turnaturi R, Parenti C, Zagni C, Lombino J, Amata E, Marrazzo A, Pasquinucci L, Rescifina A. Design, synthesis, in vitro evaluation, and molecular modeling studies of N-substituted benzomorphans, analogs of LP2, as novel MOR ligands. Chem Biol Drug Des 2023; 101:1382-1392. [PMID: 36813756 DOI: 10.1111/cbdd.14220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/14/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023]
Abstract
6,7-Benzomorphans have been investigated in medicinal chemistry for developing new drugs. This nucleus could be considered a versatile scaffold. The physicochemical properties of benzomorphan N-substituent are crucial in achieving a definite pharmacological profile at opioid receptors. Thus, the dual-target MOR/DOR ligands LP1 and LP2 were obtained through N-substituent modifications. Specifically, LP2, bearing as N-substituent the (2R/S)-2-methoxy-2- phenylethyl group, is a dual-target MOR/DOR agonist and is successful in animal models of inflammatory and neuropathic pain. To obtain new opioid ligands, we focused on the design and synthesis of LP2 analogs. First, the 2-methoxyl group of LP2 was replaced by an ester or acid functional group. Then, spacers of different lengths were introduced at N-substituent. In-vitro, their affinity profile versus opioid receptors has been performed through competition binding assays. Molecular modeling studies were conducted to deeply analyze the binding mode and the interactions between the new ligands and all opioid receptors.
Collapse
Affiliation(s)
- Giuliana Costanzo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Vincenzo Patamia
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | - Rita Turnaturi
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | - Carmela Parenti
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | - Chiara Zagni
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | - Jessica Lombino
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | - Emanuele Amata
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | - Agostino Marrazzo
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | - Lorella Pasquinucci
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| | - Antonio Rescifina
- Department of Drug and Health Sciences, University of Catania, Catania, Italy
| |
Collapse
|
6
|
Uludag N, Duran E. An Improved Approach to the Synthesis of (±)-Noruleine. ORG PREP PROCED INT 2022. [DOI: 10.1080/00304948.2021.2022923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Nesimi Uludag
- Department of Chemistry, Organic Division, Faculty of Sciences and Arts, Namık Kemal University, Tekirdag, Turkey
| | - Ebru Duran
- Department of Chemistry, Organic Division, Faculty of Sciences and Arts, Namık Kemal University, Tekirdag, Turkey
| |
Collapse
|
7
|
Gálvez JA, Badorrey R, Mahía A, Díaz-de-Villegas MD. Asymmetric synthesis of (1R,5S)-2-methyl-6,7-benzomorphan via Aza-Prins reaction. Chirality 2021; 33:543-548. [PMID: 34279050 DOI: 10.1002/chir.23338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/06/2021] [Indexed: 11/09/2022]
Abstract
(1R,5S)-2-Methyl-6,7-benzomorphan has been synthesised from (R)-(benzyloxy)(phenyl)acetaldehyde. On a 2-mmol scale Bi (OTf)3 promoted Aza-Prins reaction with N-tosylhomoallylamine afforded an 88/12 mixture of 6-oxa-2-azabicyclo[3.2.1]octanes. Major diastereoisomer was converted to enantiomerically pure (2S,4S)-2-benzyl-1- methylpiperidin-4-ol via a high-yielding sequence hydrogenolysis/N-detosylation/N-methylation. Acid-catalysed intramolecular Friedel-Crafts cyclisation of the piperidinol afforded (1R,5S)-2-methyl-6,7-benzomorphan in five steps with a yield of 25%.
Collapse
Affiliation(s)
- José A Gálvez
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC - Universidad de Zaragoza, Zaragoza, Spain
| | - Ramón Badorrey
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC - Universidad de Zaragoza, Zaragoza, Spain
| | - Alejandro Mahía
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.,Biocomputation and Complex Systems Physics Institute (BIFI). Joint Unit IQFR-CSIC-BIFI, Joint Unit EEAD-CSIC-BIFI, Zaragoza, Spain
| | - María D Díaz-de-Villegas
- Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC - Universidad de Zaragoza, Zaragoza, Spain
| |
Collapse
|
8
|
Pasquinucci L, Parenti C, Georgoussi Z, Reina L, Tomarchio E, Turnaturi R. LP1 and LP2: Dual-Target MOPr/DOPr Ligands as Drug Candidates for Persistent Pain Relief. Molecules 2021; 26:molecules26144168. [PMID: 34299443 PMCID: PMC8305117 DOI: 10.3390/molecules26144168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/29/2021] [Accepted: 07/06/2021] [Indexed: 12/19/2022] Open
Abstract
Although persistent pain is estimated to affect about 20% of the adult population, current treatments have poor results. Polypharmacology, which is the administration of more than one drug targeting on two or more different sites of action, represents a prominent therapeutic approach for the clinical management of persistent pain. Thus, in the drug discovery process the "one-molecule-multiple targets" strategy nowadays is highly recognized. Indeed, multitarget ligands displaying a better antinociceptive activity with fewer side effects, combined with favorable pharmacokinetic and pharmacodynamic characteristics, have already been shown. Multitarget ligands possessing non-opioid/opioid and opioid/opioid mechanisms of action are considered as potential drug candidates for the management of various pain conditions. In particular, dual-target MOPr (mu opioid peptide receptor)/DOPr (delta opioid peptide receptor) ligands exhibit an improved antinociceptive profile associated with a reduced tolerance-inducing capability. The benzomorphan-based compounds LP1 and LP2 belong to this class of dual-target MOPr/DOPr ligands. In the present manuscript, the structure-activity relationships and the pharmacological fingerprint of LP1 and LP2 compounds as suitable drug candidates for persistent pain relief is described.
Collapse
Affiliation(s)
- Lorella Pasquinucci
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
- Correspondence: (L.P.); (R.T.); Tel.: +39-095-738-4273 (L.P. & R.T.)
| | - Carmela Parenti
- Department of Drug and Health Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy;
| | - Zafiroula Georgoussi
- Laboratory of Cellular Signaling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research “Demokritos” Ag. Paraskevi-Attikis, 15310 Athens, Greece;
| | - Lorena Reina
- Postgraduate School of Clinical Pharmacology, Toxicology University of Catania, via S. Sofia n. 97, 95100 Catania, Italy;
| | - Emilia Tomarchio
- Postgraduate School of Anesthesiology and Intensive Care, University of Milan, Via Francesco Sforza, 35, 20122 Milan, Italy;
| | - Rita Turnaturi
- Department of Drug and Health Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
- Correspondence: (L.P.); (R.T.); Tel.: +39-095-738-4273 (L.P. & R.T.)
| |
Collapse
|
9
|
Delayre B, Fung C, Wang Q, Zhu J. Enantioselective Total Synthesis of (+)‐Nordasycarpidone, (+)‐Dasycarpidone, and (+)‐Uleine. Helv Chim Acta 2021. [DOI: 10.1002/hlca.202100088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Bastien Delayre
- Laboratory of Synthesis and Natural Products Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne EPFL-SB-ISIC-LSPN BCH5304, CH- 1015 Lausanne Switzerland
| | - Cédric Fung
- Laboratory of Synthesis and Natural Products Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne EPFL-SB-ISIC-LSPN BCH5304, CH- 1015 Lausanne Switzerland
| | - Qian Wang
- Laboratory of Synthesis and Natural Products Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne EPFL-SB-ISIC-LSPN BCH5304, CH- 1015 Lausanne Switzerland
| | - Jieping Zhu
- Laboratory of Synthesis and Natural Products Institute of Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne EPFL-SB-ISIC-LSPN BCH5304, CH- 1015 Lausanne Switzerland
| |
Collapse
|
10
|
Spetea M, Schmidhammer H. Kappa Opioid Receptor Ligands and Pharmacology: Diphenethylamines, a Class of Structurally Distinct, Selective Kappa Opioid Ligands. Handb Exp Pharmacol 2021; 271:163-195. [PMID: 33454858 DOI: 10.1007/164_2020_431] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The kappa opioid receptor (KOR), a G protein-coupled receptor, and its endogenous ligands, the dynorphins, are prominent members of the opioid neuromodulatory system. The endogenous kappa opioid system is expressed in the central and peripheral nervous systems, and has a key role in modulating pain in central and peripheral neuronal circuits and a wide array of physiological functions and neuropsychiatric behaviors (e.g., stress, reward, emotion, motivation, cognition, epileptic seizures, itch, and diuresis). We review the latest advances in pharmacology of the KOR, chemical developments on KOR ligands with advances and challenges, and therapeutic and potential applications of KOR ligands. Diverse discovery strategies of KOR ligands targeting natural, naturally derived, and synthetic compounds with different scaffolds, as small molecules or peptides, with short or long-acting pharmacokinetics, and central or peripheral site of action, are discussed. These research efforts led to ligands with distinct pharmacological properties, as agonists, partial agonists, biased agonists, and antagonists. Differential modulation of KOR signaling represents a promising strategy for developing pharmacotherapies for several human diseases, either by activating (treatment of pain, pruritus, and epilepsy) or blocking (treatment of depression, anxiety, and addiction) the receptor. We focus on the recent chemical and pharmacological advances on diphenethylamines, a new class of structurally distinct, selective KOR ligands. Design strategies and investigations to define structure-activity relationships together with in vivo pharmacology of diphenethylamines as agonists, biased agonists, and antagonists and their potential use as therapeutics are discussed.
Collapse
Affiliation(s)
- Mariana Spetea
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria.
| | - Helmut Schmidhammer
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| |
Collapse
|
11
|
Schmidhammer H, Erli F, Guerrieri E, Spetea M. Development of Diphenethylamines as Selective Kappa Opioid Receptor Ligands and Their Pharmacological Activities. Molecules 2020; 25:molecules25215092. [PMID: 33147885 PMCID: PMC7663249 DOI: 10.3390/molecules25215092] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 02/01/2023] Open
Abstract
Among the opioid receptors, the kappa opioid receptor (KOR) has been gaining substantial attention as a promising molecular target for the treatment of numerous human disorders, including pain, pruritus, affective disorders (i.e., depression and anxiety), drug addiction, and neurological diseases (i.e., epilepsy). Particularly, the knowledge that activation of the KOR, opposite to the mu opioid receptor (MOR), does not produce euphoria or leads to respiratory depression or overdose, has stimulated the interest in discovering ligands targeting the KOR as novel pharmacotherapeutics. However, the KOR mediates the negative side effects of dysphoria/aversion, sedation, and psychotomimesis, with the therapeutic promise of biased agonism (i.e., selective activation of beneficial over deleterious signaling pathways) for designing safer KOR therapeutics without the liabilities of conventional KOR agonists. In this review, the development of new KOR ligands from the class of diphenethylamines is presented. Specifically, we describe the design strategies, synthesis, and pharmacological activities of differently substituted diphenethylamines, where structure–activity relationships have been extensively studied. Ligands with distinct profiles as potent and selective agonists, G protein-biased agonists, and selective antagonists, and their potential use as therapeutic agents (i.e., pain treatment) and research tools are described.
Collapse
MESH Headings
- Analgesics, Opioid/chemistry
- Analgesics, Opioid/therapeutic use
- Humans
- Ligands
- Pain/drug therapy
- Pain/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/chemistry
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/chemistry
- Receptors, Opioid, mu/metabolism
- Structure-Activity Relationship
Collapse
|
12
|
Pasquinucci L, Parenti C, Ruiz-Cantero MC, Georgoussi Z, Pallaki P, Cobos EJ, Amata E, Marrazzo A, Prezzavento O, Arena E, Dichiara M, Salerno L, Turnaturi R. Novel N-Substituted Benzomorphan-Based Compounds: From MOR-Agonist/DOR-Antagonist to Biased/Unbiased MOR Agonists. ACS Med Chem Lett 2020; 11:678-685. [PMID: 32435370 PMCID: PMC7236032 DOI: 10.1021/acsmedchemlett.9b00549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/28/2020] [Indexed: 12/21/2022] Open
Abstract
Modifications at the basic nitrogen of the benzomorphan scaffold allowed the development of compounds able to segregate physiological responses downstream of the receptor signaling, opening new possibilities in opioid drug development. Alkylation of the phenyl ring in the N-substituent of the MOR-agonist/DOR-antagonist LP1 resulted in retention of MOR affinity. Moreover, derivatives 7a, 7c, and 7d were biased MOR agonists toward ERK1,2 activity stimulation, whereas derivative 7e was a low potency MOR agonist on adenylate cyclase inhibition. They were further screened in the mouse tail flick test and PGE2-induced hyperalgesia and drug-induced gastrointestinal transit.
Collapse
Affiliation(s)
- Lorella Pasquinucci
- Department
of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Carmela Parenti
- Department
of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - M. Carmen Ruiz-Cantero
- Department
of Pharmacology, Faculty of Medicine and Institute of Neuroscience,
Biomedical Research Center, University of
Granada, Parque Tecnológico de Ciencias de la Salud, 18100 Armilla, Granada, Spain
- Teófilo Hernando
Institute for Drug Discovery, 28029 Madrid, Spain
| | - Zafiroula Georgoussi
- Laboratory
of Cellular Signaling and Molecular Pharmacology, Institute of Biosciences
and Applications, National Center for Scientific
Research “Demokritos″, Ag. Paraskevi 15310, Athens, Greece
| | - Paschalina Pallaki
- Laboratory
of Cellular Signaling and Molecular Pharmacology, Institute of Biosciences
and Applications, National Center for Scientific
Research “Demokritos″, Ag. Paraskevi 15310, Athens, Greece
| | - Enrique J. Cobos
- Department
of Pharmacology, Faculty of Medicine and Institute of Neuroscience,
Biomedical Research Center, University of
Granada, Parque Tecnológico de Ciencias de la Salud, 18100 Armilla, Granada, Spain
- Teófilo Hernando
Institute for Drug Discovery, 28029 Madrid, Spain
| | - Emanuele Amata
- Department
of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Agostino Marrazzo
- Department
of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Orazio Prezzavento
- Department
of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Emanuela Arena
- Department
of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Maria Dichiara
- Department
of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Loredana Salerno
- Department
of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Rita Turnaturi
- Department
of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| |
Collapse
|
13
|
Turnaturi R, Pasquinucci L, Chiechio S, Grasso M, Marrazzo A, Amata E, Dichiara M, Prezzavento O, Parenti C. Exploiting the Power of Stereochemistry in Drug Action: 3-[(2 S,6 S,11 S)-8-Hydroxy-6,11-dimethyl-1,4,5,6-tetrahydro-2,6-methano-3-benzazocin-3(2 H)-yl]- N-phenylpropanamide as Potent Sigma-1 Receptor Antagonist. ACS Chem Neurosci 2020; 11:999-1005. [PMID: 32186844 DOI: 10.1021/acschemneuro.9b00688] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
(+)-(2S,6S,11S)- and (-)-(2R,6R,11R)-Benzomorphan derivatives have a different binding affinity for sigma-1 (σ1R) and opioid receptors, respectively. In this study, we describe the synthesis of the (+)-enantiomer [(+)-LP1] of the benzomorphan MOR agonist/DOR antagonist LP1 [(-)-LP1]. The binding affinity of both (+)-LP1 and (-)-LP1 for σ1R and sigma-2 receptor (σ2R) was tested. Moreover, (+)-LP1 opioid receptor binding affinity was also investigated. Finally, (+)-LP1 was tested in a mouse model of inflammatory pain. Our results showed a nanomolar σ1R and binding affinity for (+)-LP1. Both (+)-LP1 and (-)-LP1 elicited a significant analgesic effect in a formalin test. Differently from (-)-LP1, the analgesic effect of (+)-LP1 was not reversed by naloxone, suggesting a σ1R antagonist profile. Furthermore, σ1R agonist PRE-084 was able to unmask the σ1R antagonistic component of the benzomorphan compound. (+)-LP1 could constitute an useful lead compound to develop new analgesics based on mechanisms of action alternative to opioid receptor activation.
Collapse
MESH Headings
- Analgesics/chemistry
- Analgesics/pharmacology
- Analgesics, Opioid/pharmacology
- Animals
- Benzomorphans/chemical synthesis
- Benzomorphans/pharmacology
- Disease Models, Animal
- Mice
- Pain/drug therapy
- Receptors, Opioid/drug effects
- Receptors, Opioid/metabolism
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/metabolism
- Receptors, sigma/antagonists & inhibitors
- Structure-Activity Relationship
- Sigma-1 Receptor
Collapse
Affiliation(s)
- Rita Turnaturi
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Lorella Pasquinucci
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Santina Chiechio
- Department of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
- Oasi Research Institute-IRCCS, Troina 94018, Italy
| | - Margherita Grasso
- Department of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
- Oasi Research Institute-IRCCS, Troina 94018, Italy
| | - Agostino Marrazzo
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Emanuele Amata
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Maria Dichiara
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Orazio Prezzavento
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Carmela Parenti
- Department of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| |
Collapse
|
14
|
Slavov S, Mattes W, Beger RD. Determination of structural factors affecting binding to mu, kappa and delta opioid receptors. Arch Toxicol 2020; 94:1215-1227. [PMID: 32107589 DOI: 10.1007/s00204-020-02684-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 02/21/2020] [Indexed: 11/30/2022]
Abstract
Addiction is a complex behavioral phenomenon in which naturally occurring or synthetic chemicals modulate the response of the reward system through their binding to a variety of neuroreceptors, resulting in compulsive substance-seeking and use despite harmful consequences to the individual. Among these, the opioid receptor (OR) family and more specifically, the mu-opioid receptor (MOR) subtype plays a critical role in the addiction to powerful prescription and illicit drugs such as hydrocodone, oxycodone, fentanyl, cocaine, and methamphetamine (Contet et al. in Curr Opin Neurobiol 14(3):370-378, 2004). Conversely, agonists binding to kappa (KOR) and antagonists binding to delta opioid receptors (DOR) have been reported to induce negative reinforcing effects. As more than 700 new psychoactive substances were illegally sold between 2009 and 2016 (DEA-DCT-DIR-032-18), most of them lacking basic toxicological and pharmacological profiles, molecular modeling approaches that could quickly and reliably fill the gaps in our knowledge would be highly desirable tools for determining the effects of these synthetics. Here, we report accurate 3D-spectrometric data-activity relationship classification models for large and diverse datasets of MOR, KOR and DOR binders with areas under the receiver operating characteristic curve for the "blind" prediction sets exceeding 0.88. Structural features associated with (selective) binding to MOR, KOR and/or DOR were identified. These models could assist regulatory agencies in evaluating the health risks associated with the use of unprofiled substances as well as to help the pharmaceutical industry in its search for new drugs to combat addiction.
Collapse
Affiliation(s)
- Svetoslav Slavov
- Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR, 72079, USA.
| | - William Mattes
- Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR, 72079, USA
| | - Richard D Beger
- Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR, 72079, USA
| |
Collapse
|
15
|
Turnaturi R, Chiechio S, Salerno L, Rescifina A, Pittalà V, Cantarella G, Tomarchio E, Parenti C, Pasquinucci L. Progress in the development of more effective and safer analgesics for pain management. Eur J Med Chem 2019; 183:111701. [PMID: 31550662 DOI: 10.1016/j.ejmech.2019.111701] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/26/2019] [Accepted: 09/12/2019] [Indexed: 02/06/2023]
Abstract
Opioid analgesics have been used for thousands of years in the treatment of pain and related disorders, and have become among the most widely prescribed medications. Among opioid analgesics, mu opioid receptor (MOR) agonists are the most commonly used and are indicated for acute and chronic pain management. However, their use results in a plethora of well-described side-effects. From selective delta opioid receptor (DOR) and kappa opioid receptor (KOR) agonists to multitarget MOR/DOR and MOR/KOR ligands, medicinal chemistry provided different approaches aimed at the development of opioid analgesics with an improved pharmacological and tolerability fingerprint. The emergent medicinal chemistry strategy to develop ameliorated opioid analgesics is based upon the concept that functional selectivity for G-protein signalling is necessary for the therapeutic effect, whether β-arrestin recruitment is mainly responsible for the manifestation of side effects, including the development of tolerance after repeated administrations. This review summarises most relevant biased MOR, DOR, KOR and multitarget MOR/DOR ligands synthesised in the last decade and their pharmacological profile in "in vitro" and "in vivo" studies. Such biased ligands could have a significant impact on modern drug discovery and represent a new strategy for the development of better-tolerated drug candidates.
Collapse
Affiliation(s)
- Rita Turnaturi
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125, Catania, Italy.
| | - Santina Chiechio
- Department of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125, Catania, Italy; Oasi Research Institute-IRCCS, Troina, Italy
| | - Loredana Salerno
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Antonio Rescifina
- Department of Drug Sciences, Chemistry Section, University of Catania, Viale A. Doria, 95125, Catania, Italy
| | - Valeria Pittalà
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Giuseppina Cantarella
- Department of Biomedical and Biotechnological Sciences, Pharmacology Section, University of Catania, Catania, Italy
| | | | - Carmela Parenti
- Department of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Lorella Pasquinucci
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
| |
Collapse
|
16
|
(2S)-N-2-methoxy-2-phenylethyl-6,7-benzomorphan compound (2S-LP2): Discovery of a biased mu/delta opioid receptor agonist. Eur J Med Chem 2019; 168:189-198. [PMID: 30822708 DOI: 10.1016/j.ejmech.2019.02.043] [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: 11/23/2018] [Revised: 02/11/2019] [Accepted: 02/11/2019] [Indexed: 12/12/2022]
Abstract
The pivotal role of the stereocenter at the N-substituent of the 6,7-benzomorphan scaffold was investigated combining synthetic and pharmacological approaches. 2R- and 2S-diastereoisomers of the multitarget MOR/DOR antinociceptive ligand LP2 (1) were synthesized and their pharmacological profile was evaluated in in vitro and vivo assays. From our results, 2S-LP2 (5) showed an improved pharmacological profile in comparison to LP2 (1) and 2R-LP2 (4). 2S-LP2 (5) elicited an antinociceptive effect with a 1.5- and 3-times higher potency than LP2 (1) and R-antipode (4), respectively. In vivo effect of 2S-LP2 (5) was consistent with the improved MOR/DOR efficacy profile assessed by radioligand binding assay, to evaluate the opioid receptor affinity, and BRET assay, to evaluate the capability to promote receptor/G-protein and receptor/β-arrestin 2 interaction. 2S-LP2 (5) was able to activate, with different efficacy, G-protein pathway over β-arrestin 2, behaving as biased agonist at MOR and mainly at DOR. Considering the therapeutic potential of both multitarget MOR/DOR agonism and functional selectivity over G-protein, the 2S-LP2 (5) biased multitarget MOR/DOR agonist could provide a safer treatment opportunity.
Collapse
|
17
|
Turnaturi R, Montenegro L, Marrazzo A, Parenti R, Pasquinucci L, Parenti C. Benzomorphan skeleton, a versatile scaffold for different targets: A comprehensive review. Eur J Med Chem 2018; 155:492-502. [PMID: 29908442 DOI: 10.1016/j.ejmech.2018.06.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/23/2018] [Accepted: 06/06/2018] [Indexed: 12/21/2022]
Abstract
Despite the fact that the benzomorphan skeleton has mainly been employed in medicinal chemistry for the development of opioid analgesics, it is a versatile structure. Its stereochemistry, as well as opportune modifications at the phenolic hydroxyl group and at the basic nitrogen, play a pivotal role addressing the benzomorphan-based compounds to a specific target. In this review, we describe the structure activity-relationships (SARs) of benzomorphan-based compounds acting at sigma 1 receptor (σ1R), sigma 2 receptor (σ2R), voltage-dependent sodium channel, N-Methyl-d-Aspartate (NMDA) receptor-channel complex and other targets. Collectively, the SARs data have highlighted that the benzomorphan nucleus could be regarded as a useful template for the synthesis of drug candidates for different targets.
Collapse
Affiliation(s)
- Rita Turnaturi
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria, 6, 95100, Catania, Italy.
| | - Lucia Montenegro
- Department of Drug Sciences, Pharmaceutical Technology Section, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Agostino Marrazzo
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria, 6, 95100, Catania, Italy
| | - Rosalba Parenti
- Department of Biomedical and Biotechnological Sciences, Physiology Section, University of Catania, Catania, Italy
| | - Lorella Pasquinucci
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria, 6, 95100, Catania, Italy
| | - Carmela Parenti
- Department of Drug Sciences, Pharmacology Section, University of Catania, Viale A. Doria, 6, 95100, Catania, Italy
| |
Collapse
|
18
|
Synthesis and Structure-Activity Relationships of (-)- cis- N-Normetazocine-Based LP1 Derivatives. Pharmaceuticals (Basel) 2018; 11:ph11020040. [PMID: 29734749 PMCID: PMC6027146 DOI: 10.3390/ph11020040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/02/2018] [Accepted: 05/03/2018] [Indexed: 12/25/2022] Open
Abstract
(−)-cis-N-Normetazocine represents a rigid scaffold able to mimic the tyramine moiety of endogenous opioid peptides, and the introduction of different N-substituents influences affinity and efficacy of respective ligands at MOR (mu opioid receptor), DOR (delta opioid receptor), and KOR (kappa opioid receptor). We have previously identified LP1, a MOR/DOR multitarget opioid ligand, with an N-phenylpropanamido substituent linked to (−)-cis-N-Normetazocine scaffold. Herein, we report the synthesis, competition binding and calcium mobilization assays of new compounds 10⁻16 that differ from LP1 by the nature of the N-substituent. In radioligand binding experiments, the compounds 10⁻13, featured by an electron-withdrawing or electron-donating group in the para position of phenyl ring, displayed improved affinity for KOR (Ki = 0.85⁻4.80 μM) in comparison to LP1 (7.5 μM). On the contrary, their MOR and DOR affinities were worse (Ki = 0.18⁻0.28 μM and Ki = 0.38⁻1.10 μM, respectively) with respect to LP1 values (Ki = 0.049 and 0.033 μM). Analogous trends was recorded for the compounds 14⁻16, featured by indoline, tetrahydroquinoline, and diphenylamine functionalities in the N-substituent. In calcium mobilization assays, the compound 10 with a p-fluorophenyl in the N-substituent shared the functional profile of LP1 (pEC50MOR = 7.01), although it was less active. Moreover, the p-methyl- (11) and p-cyano- (12) substituted compounds resulted in MOR partial agonists and DOR/KOR antagonists. By contrast, the derivatives 13⁻15 resulted as MOR antagonists, and the derivative 16 as a MOR/KOR antagonist (pKBMOR = 6.12 and pKBKOR = 6.11). Collectively, these data corroborated the critical role of the N-substituent in (−)-cis-N-Normetazocine scaffold. Thus, the new synthesized compounds could represent a template to achieve a specific agonist, antagonist, or mixed agonist/antagonist functional profile.
Collapse
|
19
|
Synthesis and Structure-Activity Relationships of LP1 Derivatives: N-Methyl-N-phenylethylamino Analogues as Novel MOR Agonists. Molecules 2018; 23:molecules23030677. [PMID: 29547588 PMCID: PMC6017588 DOI: 10.3390/molecules23030677] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 11/30/2022] Open
Abstract
The opioid pharmacological profile of cis-(−)-N-normetazocine derivatives is deeply affected by the nature of their N-substituents. Here, our efforts were focused on the synthesis and pharmacological evaluation of novel derivatives of the lead LP1, a multitarget opioid analgesic compound featuring an N-phenylpropanamido substituent. LP1 derivatives 5a–d and 6a–d were characterized by flexible groups at the N-substituent that allow them to reposition themselves relative to cis-(−)-N-normetazocine nucleus, thus producing different pharmacological profiles at the mu, delta and kappa opioid receptors (MOR, DOR and KOR) in in vitro and in vivo assays. Among the series, compound 5c, with the best in vitro and in vivo profile, resulted a MOR agonist which displays a KiMOR of 6.1 nM in a competitive binding assay, and an IC50 value of 11.5 nM and an Imax of 72% in measurement of cAMP accumulation in HEK293 cells stably expressing MOR, with a slight lower efficacy than LP1. Moreover, in a mouse model of acute thermal nociception, compound 5c, intraperitoneally administered, exhibits naloxone-reversed antinociceptive properties with an ED50 of 4.33 mg/kg. These results expand our understanding of the importance of N-substituent structural variations in the opioid receptor profile of cis-(−)-N-normetazocine derivatives and identify a new MOR agonist useful for the development of novel opioid analgesics for pain treatment.
Collapse
|