1
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Structure-Activity Relationships of 7-Substituted Dimethyltyrosine-Tetrahydroisoquinoline Opioid Peptidomimetics. Molecules 2019; 24:molecules24234302. [PMID: 31779072 PMCID: PMC6930500 DOI: 10.3390/molecules24234302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 02/07/2023] Open
Abstract
The opioid receptors modulate a variety of biological functions, including pain, mood, and reward. As a result, opioid ligands are being explored as potential therapeutics for a variety of indications. Multifunctional opioid ligands, which act simultaneously at more than one type of opioid receptor, show promise for use in the treatment of addiction, pain, and other conditions. Previously, we reported the creation of bifunctional kappa opioid receptor (KOR) agonist/mu opioid receptor (MOR) partial agonist ligands from the classically delta opioid receptor (DOR) antagonist selective dimethyltyrosine-tetrahydroisoquinoline (Dmt-Tiq) scaffold through the addition of a 7-benzyl pendant on the tetrahydroisoquinoline ring. This study further explores the structure–activity relationships surrounding 7-position pendants on the Dmt-Tiq scaffold. Some analogues maintain a KOR agonist/MOR partial agonist profile, which is being explored in the development of a treatment for cocaine addiction. Others display a MOR agonist/DOR antagonist profile, which has potential to be used in the creation of a less addictive pain medication. Ultimately, we report the synthesis and in vitro evaluation of novel opioid ligands with a variety of multifunctional profiles.
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2
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Montgomery D, Anand JP, Griggs NW, Fernandez TJ, Hartman JG, Sánchez-Santiago AA, Pogozheva ID, Traynor JR, Mosberg HI. Novel Dimethyltyrosine-Tetrahydroisoquinoline Peptidomimetics with Aromatic Tetrahydroisoquinoline Substitutions Show in Vitro Kappa and Mu Opioid Receptor Agonism. ACS Chem Neurosci 2019; 10:3682-3689. [PMID: 31199621 DOI: 10.1021/acschemneuro.9b00250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The dimethyltyrosine-tetrahydroisoquinoline (Dmt-Tiq) scaffold was originally developed in the production of selective delta opioid receptor (DOR) antagonists. Installation of a 7-benzyl pendant on the tetrahydroisoquinoline core of this classic opioid scaffold introduced kappa opioid receptor (KOR) agonism. Further modification of this pendant resulted in retention of KOR agonism and the addition of mu opioid receptor (MOR) partial agonism, a bifunctional profile with potential to be used in the treatment of cocaine addiction.
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Affiliation(s)
- Deanna Montgomery
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jessica P. Anand
- Department of Pharmacology, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
- Edward F. Domino Research Center, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nicholas W. Griggs
- Department of Pharmacology, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Thomas J. Fernandez
- Department of Pharmacology, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joshua G. Hartman
- Department of Pharmacology, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Ashley A. Sánchez-Santiago
- Department of Pharmacology, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Irina D. Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - John R. Traynor
- Department of Pharmacology, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
- Edward F. Domino Research Center, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Henry I. Mosberg
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
- Edward F. Domino Research Center, Medical School, University of Michigan, Ann Arbor, Michigan 48109, United States
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3
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Kohlmann J, Braun T, Laubenstein R, Herrmann R. Suzuki-Miyaura Cross-Coupling Reactions of Highly Fluorinated Arylboronic Esters: Catalytic Studies and Stoichiometric Model Reactions on the Transmetallation Step. Chemistry 2017; 23:12218-12232. [DOI: 10.1002/chem.201700549] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Indexed: 12/23/2022]
Affiliation(s)
- Johannes Kohlmann
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Thomas Braun
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Reik Laubenstein
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Roy Herrmann
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Straße 2 12489 Berlin Germany
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4
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Kormos CM, Gichinga MG, Maitra R, Runyon SP, Thomas JB, Brieaddy LE, Mascarella SW, Navarro HA, Carroll FI. Design, synthesis, and biological evaluation of (3R)-1,2,3,4-tetrahydro-7-hydroxy-N-[(1S)-1-[[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethyl-1-piperidinyl]methyl]-2-methylpropyl]-3-isoquinolinecarboxamide (JDTic) analogues: in vitro pharmacology and ADME profile. J Med Chem 2014; 57:7367-81. [PMID: 25133923 PMCID: PMC4161151 DOI: 10.1021/jm5008177] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
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JDTic analogues 4–15 which have
the hydroxyl groups replaced with other groups were synthesized and
their in vitro efficacy at the μ, δ, and κ opioid
receptors determined and compared to JDTic using [35S]GTPγS
assays. Compounds 4, 5, 6, 13, 14, and 15 had Ke = 0.024, 0.01, 0.039, 0.02, 0.11, and 0.041 nM compared
to the Ke = 0.02 nM for JDTic at the κ
receptor and were highly selective for the κ receptor relative
to the μ and δ opioid receptors. Unexpectedly, replacement
of the 3-hydroxyl substituent of the 4-(3-hydroxyphenyl) group of
JDTic with a H, F, or Cl substituent leads to potent and selective
KOR antagonists. In vitro studies to determine various ADME properties
combined with calculated TPSA, clogP, and logBB values suggests that
the potent and selective κ opioid receptors 4, 5, 13, and 14 deserve consideration
for further development toward potential drugs for CNS disorders.
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Affiliation(s)
- Chad M Kormos
- Research Triangle Institute , 3040 Cornwallis Road, P.O. Box 12194, Research Triangle Park, North Carolina 27709-6679, United States
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5
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6
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Fichna J, Piestrzeniewicz M, Gach K, Poels J, Burgeon E, Vanden Broeck J, Janecka A. [d-1-Nal4]endomorphin-2 is a potent μ-opioid receptor antagonist in the aequorin luminescence-based calcium assay. Life Sci 2006; 79:1094-9. [PMID: 16624333 DOI: 10.1016/j.lfs.2006.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Accepted: 03/08/2006] [Indexed: 11/30/2022]
Abstract
A functional assay, based on aequorin-derived luminescence triggered by receptor-mediated changes in Ca(2+) levels, was used to examine relative potency and efficacy of the micro-opioid receptor antagonists. A series of position 3- and 4-substituted endomorphin-2 (Tyr-Pro-Phe-Phe-NH(2)) analogues containing D-3-(1-naphthyl)-alanine (D-1-Nal) or D-3-(2-naphthyl)-alanine (D-2-Nal), which were previously shown to reverse antinociception induced by endomorphin-2 in the in vivo hot-plate test in mice, was tested in the aequorin luminescence-based calcium assay to examine their micro-opioid antagonist potency in vitro. A recombinant mammalian cell line expressing the micro-opioid receptor together with a luminescent reporter protein, apoaequorin, was used in the study. The results obtained in this functional assay indicated that analogues with D-1-Nal or D-2-Nal substitutions in position 4 of endomorphin-2 are strong micro-opioid receptor antagonists, while those substituted in position 3 are partial agonists. Exceptional antagonist potency in the calcium assay was observed for [D-1-Nal(4)]endomorphin-2. The pA(2) value for this analogue was 7.95, compared to the value of 8.68 obtained for the universal, non-selective opioid antagonist of the alkaloid structure, naloxone. The obtained results were compared with the data from the hot-plate test in mice. In that in vivo assay [D-1-Nal(4)]endomorphin-2 was also the most potent analogue of the series.
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Affiliation(s)
- Jakub Fichna
- Laboratory of Biomolecular Chemistry, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland
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7
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Li T, Shiotani K, Miyazaki A, Fujita Y, Tsuda Y, Ambo A, Sasaki Y, Jinsmaa Y, Marczak E, Bryant SD, Lazarus LH, Okada Y. New series of potent delta-opioid antagonists containing the H-Dmt-Tic-NH-hexyl-NH-R motif. Bioorg Med Chem Lett 2005; 15:5517-20. [PMID: 16183273 DOI: 10.1016/j.bmcl.2005.08.073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Revised: 08/20/2005] [Accepted: 08/26/2005] [Indexed: 11/20/2022]
Abstract
Heterodimeric compounds H-Dmt-Tic-NH-hexyl-NH-R (R=Dmt, Tic, and Phe) exhibited high affinity to delta- (K(i)delta=0.13-0.89nM) and mu-opioid receptors (K(i)mu=0.38-2.81nM) with extraordinary potent delta antagonism (pA(2)=10.2-10.4). These compounds represent the prototype for a new class of structural homologues lacking mu-opioid receptor-associated agonism (IC(50)=1.6-5.8muM) based on the framework of bis-[H-Dmt-NH]-alkyl (Okada, Y.; Tsuda, Y.; Fujita, Y.; Yokoi, T.; Sasaki, Y.; Ambo, A.; Konishi, R.; Nagata, M.; Salvadori, S.; Jinsmaa, Y.; Bryant, S. D.; Lazarus, L. H. J. Med. Chem.2003, 46, 3201), which exhibited both high mu affinity and bioactivity.
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Affiliation(s)
- Tingyou Li
- The Graduate School of Food and Medicinal Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
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8
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Van den Eynde I, Laus G, Schiller PW, Kosson P, Chung NN, Lipkowski AW, Tourwé D. A new structural motif for mu-opioid antagonists. J Med Chem 2005; 48:3644-8. [PMID: 15887972 DOI: 10.1021/jm0491795] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
On the basis of the structural features of the Dmt-Tic pharmacophore, a new motif leading to a fairly potent mu-opioid antagonist is described. This motif contains the 4-amino-1,2,4,5-tetrahydro-2-benzazepine-3-one skeleton as a substitute for the Tic residue, which provides the conformational constraint compatible with the mu-opioid receptor. The stereoselective synthesis of four stereoisomers is performed starting from homochiral 2',6'-dimethyltyrosine (Dmt) and o-aminomethylphenylalanine.
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Affiliation(s)
- Isabelle Van den Eynde
- Eenheid Organische Chemie, Vrije Universiteit Brussel, 2, Pleinlaan, B-1050 Brussels, Belgium
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9
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Balboni G, Salvadori S, Guerrini R, Negri L, Giannini E, Bryant SD, Jinsmaa Y, Lazarus LH. Synthesis and opioid activity of N,N-dimethyl-Dmt-Tic-NH-CH(R)-R' analogues: acquisition of potent delta antagonism. Bioorg Med Chem 2004; 11:5435-41. [PMID: 14642588 DOI: 10.1016/j.bmc.2003.09.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
N,N-Dimethylation of the H-Dmt-Tic-NH-CH(R)-R' series of compounds produced no significant affect on the high delta-opioid receptor affinity (K(i)=0.035-0.454 nM), but dramatically decreased that for the micro-opioid receptor. The effect of N-methylation was independent of the length of the linker (R); however, the bioactivities were affected by the chemical composition of the third aromatic group (R'): phenyl (Ph) (5'-8') elicited a greater reduction in micro-affinity (40-70-fold) compared to analogues containing 1H-benzimidazole-2-yl (Bid) (9-fold). The major consequences of N,N-dimethylation on in vitro bioactivity were: (i). a loss of delta-agonism coupled with the appearance of potent delta antagonism (4'-7') (pA(2)=8.14-9.47), while 1 exhibited only a 160-fold decreased delta agonism (1') and the delta antagonism of 8 enhanced >10-fold (pA(2)=10.62, 8'); and (ii). a consistent loss of micro-affinity resulted in enhanced delta-opioid receptor selectivity. With the exception of compound 1', the change in the hydrophobic environment at the N-terminus and formation of a tertiary amine by N,N-dimethylation in analogues of the Dmt-Tic pharmacophore produced potent delta-selective antagonists.
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Affiliation(s)
- Gianfranco Balboni
- Department of Toxicology, University of Cagliary, I-09126, Cagliary, Italy
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10
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Bryant SD, Jinsmaa Y, Salvadori S, Okada Y, Lazarus LH. Dmt and opioid peptides: a potent alliance. Biopolymers 2004; 71:86-102. [PMID: 12767112 DOI: 10.1002/bip.10399] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The introduction of the Dmt (2',6'-dimethyl-L-tyrosine)-Tic pharmacophore into the design of opioid ligands produced an extraordinary family of potent delta-opioid receptor antagonists and heralded a new phase in opioid research. First reviewed extensively in 1998, the incorporation of Dmt into a diverse group of opioid molecules stimulated the opioid field leading to the development of unique analogues with remarkable properties. This overview will document the crucial role played by this residue in the proliferation of opioid peptides with high receptor affinity (K(i) equal to or less than 1 nM) and potent bioactivity. The discussion will include the metamorphosis between delta-opioid receptor antagonists to delta-agonists based solely on subtle structural changes at the C-terminal region of the Dmt-Tic pharmacophore as well as their behavior in vivo. Dmt may be considered promiscuous due to the acquisition of potent mu-agonism by dermorphin and endomorphin derivatives as well as by a unique class of opioidmimetics containing two Dmt residues separated by alkyl or pyrazinone linkers. Structural studies on the Dmt-Tic compounds were enhanced tremendously by x-ray diffraction data for three potent and biologically diverse Dmt-Tic opioidmimetics that led to the development of pharmacophores for both delta-opioid receptor agonists and antagonists. Molecular modeling studies of other unique Dmt opioid analogues illuminated structural differences between delta- and mu-receptor ligand interactions. The future of these compounds as therapeutic applications for various medical syndromes including the control of cancer-associated pain is only a matter of time and perseverance.
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Affiliation(s)
- Sharon D Bryant
- Peptide Neurochemistry, LCBRA, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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11
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Pagé D, Nguyen N, Bernard S, Coupal M, Gosselin M, Lepage J, Adam L, Brown W. New scaffolds in the development of mu opioid-receptor ligands. Bioorg Med Chem Lett 2003; 13:1585-9. [PMID: 12699761 DOI: 10.1016/s0960-894x(03)00194-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A new class of mu selective receptor antagonists has been developed using a combinatorial approach based on previously reported Dmt-Tic dipeptide ligands. Modified tetrahydroisoquinoline (Tiq) residues were reacted with different electrophiles in order to create novel molecules that would mimic the original dipeptide. A specific class of thioureas bearing basic pyrrolidine residues were shown to give good binding affinities. Further alkylation of the pyrrolidine ring with benzyl derivatives also proved to increase the mu binding affinity. In addition, it was demonstrated that mu binding was enhanced by the presence of polar groups around the benzyl ring having hydrogen-bonding character (donor/acceptor). This new class of ligands represents a novel scaffold in the development of opioid analogues.
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Affiliation(s)
- Daniel Pagé
- Department of Chemistry, AstraZeneca R&D Montreal, 7171 Frederick-Banting, Saint-Laurent, Quebec, Canada H4S 1Z9.
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12
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Okada Y, Fujita Y, Motoyama T, Tsuda Y, Yokoi T, Li T, Sasaki Y, Ambo A, Jinsmaa Y, Bryant SD, Lazarus LH. Structural studies of [2',6'-dimethyl-L-tyrosine1]endomorphin-2 analogues: enhanced activity and cis orientation of the Dmt-Pro amide bond. Bioorg Med Chem 2003; 11:1983-94. [PMID: 12670649 DOI: 10.1016/s0968-0896(03)00068-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Analogues of endomorphin-2 (EM-2: Tyr-Pro-Phe-Phe-NH(2)) (1) were designed to examine the importance of each residue on mu-opioid receptor interaction. Replacement of Tyr(1) by 2',6'-dimethyl-L-tyrosine (Dmt) (9-12) exerted profound effects: [Dmt(1)]EM-2 (9) elevated mu-opioid affinity 4.6-fold (K(i mu=0.15 nM) yet selectivity fell 330-fold as delta-affinity rose (K(i)delta=28.2 nM). This simultaneous increased mu- and delta-receptor bioactivities resulted in dual agonism (IC(50)=0.07 and 1.87 nM, respectively). While substitution of Phe(4) by a phenethyl group (4) decreased mu affinity (K(i)mu=13.3 nM), the same derivative containing Dmt (12) was comparable to EM-2 but also acquired weak delta antagonism (pA(2)=7.05). 1H NMR spectroscopy revealed a trans configuration (1:2 to 1:3, cis/trans) in the Tyr-Pro amide bond, but a cis configuration (5:3 to 13:7, cis/trans) with Dmt-Pro analogues.
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Affiliation(s)
- Yoshio Okada
- Faculty of Pharmaceutical Sciences, Department of Medicinal Chemistry, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan.
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13
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Balboni G, Salvadori S, Guerrini R, Negri L, Giannini E, Jinsmaa Y, Bryant SD, Lazarus LH. Potent delta-opioid receptor agonists containing the Dmt-Tic pharmacophore. J Med Chem 2002; 45:5556-63. [PMID: 12459023 DOI: 10.1021/jm020336e] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Conversion of delta-opioid receptor antagonists containing the 2',6'-dimethyl-L-tyrosine (Dmt)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) pharmacophore into potent delta-agonists required a third heteroaromatic nucleus, such as 1H-benzimidazole-2-yl (Bid) and a linker of specified length both located C-terminally to Tic in the general formula H-Dmt-Tic-NH-CH(R)-R'. The distance between Tic and Bid is a determining factor responsible for the acquisition of delta agonism (2, 2', 3, 4, 6) or delta antagonism (8). Compounds containing a C-terminal Ala (1, 1'), Asp (5), or Asn (7) with an amide (1, 1', 5) or free acid group (7) served as delta-antagonist controls lacking the third heteroaromatic ring. A change in chirality of the spacer (2, 2') or inclusion of a negative charge via derivatives of Asp (4, 6) resulted in potent delta agonism and moderate mu agonism, although delta-receptor affinity decreased about 10-fold for 4 while mu affinity fell by over 2 orders of magnitude. Repositioning of the negative charge in the linker altered activity: H-Dmt-Tic-NH-CH(CH(2)-Bid)COOH (6) maintained high delta affinity (K(i) = 0.042 nM) and delta agonism (IC(50) = 0.015 nM), but attachment of the free acid group to Bid [H-Dmt-Tic-NH-CH(2)-Bid(CH(2)-COOH) (9)] reconstituted delta antagonism (K(e) = 0.27 nM). The data demonstrate that a linker separating the Dmt-Tic pharmacophore and Bid, regardless of the presence of a negative charge, is important in the acquisition of opioids exhibiting potent delta agonism and weak mu agonism from a parent delta antagonist.
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MESH Headings
- Animals
- Benzimidazoles/chemical synthesis
- Benzimidazoles/chemistry
- Benzimidazoles/pharmacology
- Binding, Competitive
- Brain/metabolism
- Dipeptides/chemical synthesis
- Dipeptides/chemistry
- Dipeptides/pharmacology
- Electric Stimulation
- Guinea Pigs
- In Vitro Techniques
- Intestine, Small/innervation
- Models, Molecular
- Muscle Contraction/drug effects
- Muscle, Smooth/drug effects
- Muscle, Smooth/innervation
- Myenteric Plexus/drug effects
- Neuromuscular Junction/drug effects
- Neuromuscular Junction/physiology
- Radioligand Assay
- Rats
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/metabolism
- Structure-Activity Relationship
- Tetrahydroisoquinolines
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Affiliation(s)
- Gianfranco Balboni
- Department of Toxicology, University of Cagliari, I-09126 Cagliari, Italy
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14
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Bryant SD, George C, Flippen-Anderson JL, Deschamps JR, Salvadori S, Balboni G, Guerrini R, Lazarus LH. Crystal structures of dipeptides containing the Dmt-Tic pharmacophore. J Med Chem 2002; 45:5506-13. [PMID: 12459018 DOI: 10.1021/jm020330p] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The crystal structures of three analogues of the potent delta-opioid receptor antagonist H-Dmt-Tic-OH (2',6'-dimethyl-L-tyrosine-L-1,2,3,4-tetrahydroisoquinoline-3-carboxylate), N,N (CH(3))(2)-Dmt-Tic-OH (1), H-Dmt-Tic-NH-1-adamantane (2), and N,N(CH(3))(2)-Dmt-Tic-NH-1-adamantane (3) were determined by X-ray single-crystal analysis. Crystals of 1 were grown by slow evaporation, while those of 2 and 3 were grown by vapor diffusion. Compounds 1 and 3 crystallized in the monoclinic space group P2(1), and 2 crystallized in the tetragonal space group P4(3). Common backbone atom superimpositions of structures derived from X-ray diffraction studies resulted in root-mean-square (rms) deviations of 0.2-0.5 A, while all-atom superimpositions gave higher rms deviations from 0.8 to 1.2 A. Intramolecular distances between the aromatic ring centers of Dmt and Tic were 5.1 A in 1, 6.3 A in 2, and 6.5 A in 3. The orientation of the C-terminal substituent 1-adamantane in 2 and 3 was affected by differences in the psi torsion angles and strong hydrogen bonds with adjacent molecules. Despite the high delta-opioid receptor affinity exhibited by each analogue (K(i) < 0.3 nM), high mu receptor affinity (K(i) < 1 nM) was manifested only with the bulky C-terminal 1-adamantane analogues 2 and 3. Furthermore, the bioactivity of both 2 and 3 exhibited mu-agonism, while 3 also had potent delta-antagonist activity. Those data demonstrated that a C-terminal hydrophobic group was an important determinant for eliciting mu-agonism, whereas N-methylation maintained delta-antagonism. Furthermore, the structural results support the hypothesis that expanded dimensions between aromatic nuclei is important for acquiring mu-agonism.
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Affiliation(s)
- Sharon D Bryant
- Peptide Neurochemistry, LCBRA, National Institute of Environmental Health Sciences, P.O. Box 12233, Mail Drop C3-04, Research Triangle Park, North Carolina 27709, USA.
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15
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Balboni G, Guerrini R, Salvadori S, Bianchi C, Rizzi D, Bryant SD, Lazarus LH. Evaluation of the Dmt-Tic pharmacophore: conversion of a potent delta-opioid receptor antagonist into a potent delta agonist and ligands with mixed properties. J Med Chem 2002; 45:713-20. [PMID: 11806723 DOI: 10.1021/jm010449i] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Analogues of the 2',6'-dimethyl-L-tyrosine (Dmt)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) pharmacophore were prepared to test the hypothesis that a "spacer" and a third aromatic center in opioid peptides are required to convert a delta-antagonist into ligands with delta-agonist or with mixed delta-antagonist/mu-agonist properties. Potent delta-agonists and bifunctional compounds with high delta- and mu-opioid receptor affinities were obtained by varying the spacer length [none, NH-CH(2), NH-CH(2)-CH(2), Gly-NH-CH(2)] and C-terminal aromatic nucleus [1H-benzimidazole-2-yl, phenyl (Ph) and benzyl groups]. C-terminal modification primarily affected mu-opioid receptor affinities, which increased maximally 1700-fold relative to the prototype delta-antagonist H-Dmt-Tic-NH(2) and differentially modified bioactivity. In the absence of a spacer (1), the analogue exhibited dual delta-agonism (pEC(50), 7.28) and delta-antagonism (pA(2), 7.90). H-Dmt-Tic-NH-CH(2)-1H-benzimidazole-2-yl (Bid) (2) became a highly potent delta-agonist (pEC(50), 9.90), slightly greater than deltorphin C (pEC(50), 9.56), with mu-agonism (pE(50), 7.57), while H-Dmt-Tic-Gly-NH-CH(2)-Bid (4) retained potent delta-antagonism (pA(2), 9.0) but with an order of magnitude less mu-agonism. Similarly, H-Dmt-Tic-Gly-NH-Ph (5) had nearly equivalent high delta-agonism (pEC(50), 8.52) and mu-agonism (pEC(50), 8.59), while H-Dmt-Tic-Gly-NH-CH(2)-Ph (6) whose spacer was longer by a single methylene group exhibited potent delta-antagonism (pA(2), 9.25) and very high mu-agonism (pEC(50), 8.57). These data confirm that the distance between the Dmt-Tic pharmacophore and a third aromatic nucleus is an important criterion in converting Dmt-Tic from a highly potent delta-antagonist into a potent delta-agonist or into ligands with mixed delta- and mu-opioid properties.
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Affiliation(s)
- Gianfranco Balboni
- Department of Toxicology, University of Cagliary, I09126 Cagliary, Italy
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Pagé D, Naismith A, Schmidt R, Coupal M, Labarre M, Gosselin M, Bellemare D, Payza K, Brown W. Novel C-terminus modifications of the Dmt-Tic motif: a new class of dipeptide analogues showing altered pharmacological profiles toward the opioid receptors. J Med Chem 2001; 44:2387-90. [PMID: 11448220 DOI: 10.1021/jm015532k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The design, synthesis and pharmacological evaluation of a novel class of Dmt-Tic dipeptide analogues are described. These resulting analogues bearing different C-terminal functionalities were found to bind to the human delta receptor with high affinity. One specific class of dipeptides bearing urea/thiourea functionalities showed partial to full activation of the delta receptor. Several dipeptides also showed good binding affinities with full activation of the human kappa receptor, a novel property for those ligands.
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MESH Headings
- Dipeptides/chemical synthesis
- Dipeptides/chemistry
- Dipeptides/metabolism
- Humans
- Isoquinolines/chemistry
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/metabolism
- Tetrahydroisoquinolines
- Tyrosine/analogs & derivatives
- Tyrosine/chemistry
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Affiliation(s)
- D Pagé
- Departments of Chemistry and Pharmacology, AstraZeneca R&D Montreal, 7171 Frederick-Banting, Saint-Laurent, Quebec, Canada H4S 1Z9.
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17
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Santagada V, Balboni G, Caliendo G, Guerrini R, Salvadori S, Bianchi C, Bryant SD, Lazarus LH. Assessment of substitution in the second pharmacophore of Dmt-Tic analogues. Bioorg Med Chem Lett 2000; 10:2745-8. [PMID: 11133082 DOI: 10.1016/s0960-894x(00)00569-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Dmt-Tic pharmacophore exhibits potent delta-opioid receptor antagonism. Analogues with substitutions in the second pharmacophore with (1, 1') or without a COOH function (2-9) were synthesized: several had high delta affinity (1', 2, 7, and 9), but exhibited low to non-selectivity toward mu receptors similar to H-Dmt-Tic-amide and H-Dmt-Tic-ol. Functional bioactivity indicated high delta antagonism (pA2 7.4-7.9) (1', 2, and 9) and modest mu agonism, pEC50 (6.1-6.3) (1', 2, 8, and 9), but with Emax values analogous to dermorphin. These Dmt-Tic analogues with mixed delta antagonist/mu agonist properties would appear to be better candidates as analgesics than pure mu agonists.
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Affiliation(s)
- V Santagada
- Medicinal Chemistry and Toxicology, University of Naples, Italy
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Schiller PW, Weltrowska G, Berezowska I, Nguyen TM, Wilkes BC, Lemieux C, Chung NN. The TIPP opioid peptide family: development of delta antagonists, delta agonists, and mixed mu agonist/delta antagonists. Biopolymers 2000; 51:411-25. [PMID: 10797230 DOI: 10.1002/(sici)1097-0282(1999)51:6<411::aid-bip4>3.0.co;2-z] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The discovery of the prototype delta opioid antagonists TIPP (H-Tyr-Tic-Phe-Phe-OH) and TIP (H-Tyr-Tic-Phe-OH) in 1992 was followed by extensive structure-activity relationship studies, leading to the development of analogues that are of interest as pharmacological tools or as potential therapeutic agents. Stable TIPP-derived delta opioid antagonists with subnanomolar delta receptor binding affinity and extraordinary delta receptor selectivity include TIPP[Psi] (H-Tyr-TicPsi[CH(2)NH]Phe-Phe-OH] and TICP[Psi] (H-Tyr-TicPsi[CH(2)NH]Cha-Phe-OH); Cha: cyclohexylalanine), which are widely used in opioid research. Theoretical conformational analyses in conjunction with the pharmacological characterization of conformationally constrained TIPP analogues led to a definitive model of the receptor-bound conformation of H-Tyr-Tic-(Phe-Phe)-OH-related delta opioid antagonists, which is characterized by all-trans peptide bonds. Further structure-activity studies revealed that the delta antagonist vs delta agonist behavior of TIP(P)-derived compounds depended on very subtle structural differences in diverse locations of the molecule and suggested a delta receptor model involving a number of different inactive receptor conformations. A further outcome of these studies was the identification of a new class of potent and very selective dipeptide delta agonists of the general formula H-Tyr-Tic-NH-X (X = arylalkyl), which are of interest for drug development because of their low molecular weight and lipophilic character. Most interestingly, TIPP analogues containing a C-terminal carboxamide group displayed a mixed mu agonist/delta antagonist profile, and thus were expected to be analgesics with a low propensity to produce tolerance and physical dependence. This turned out to be the case with the TIPP-derived mu agonist/delta antagonist DIPP-NH(2)[Psi] (H-Dmt-TicPsi[CH(2)NH]Phe-Phe-NH(2)); Dmt: 2',6'- dimethyltyrosine).
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Affiliation(s)
- P W Schiller
- Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montreal, Quebec, Canada
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