TY - JOUR
T1 - A structure-activity relationship study and combinatorial synthetic approach of C-terminal modified bifunctional peptides that are δ/μ opioid receptor agonists and neurokinin 1 receptor antagonists
AU - Yamamoto, Takashi
AU - Nair, Padma
AU - Vagner, Josef
AU - Largent-Milnes, Tally
AU - Davis, Peg
AU - Ma, Shou Wu
AU - Navratilova, Edita
AU - Moye, Sharif
AU - Tumati, Suneeta
AU - Lai, Josephine
AU - Yamamura, Henry I.
AU - Vanderah, Todd W.
AU - Porreca, Frank
AU - Hruby, Victor J
PY - 2008/3/13
Y1 - 2008/3/13
N2 - A series of bifunctional peptides with opioid agonist and substance P antagonist bioactivities were designed with the concept of overlapping pharmacophores. In this concept, the bifunctional peptides were expected to interact with each receptor separately in the spinal dorsal horn where both the opioid receptors and the NK1 receptors were found to be expressed, to show an enhanced analgesic effect, no opioid-induced tolerance, and to provide better compliance than coadministration of two drugs. Compounds were synthesized using a two-step combinatorial method for C-terminal modification. In the method, the protected C-terminal-free carboxyl peptide, Boc-Tyr(tBu)-D-Ala-Gly Phe-Pro-Leu-Trp(Boc)-OH, was synthesized as a shared intermediate using Fmoc solid phase chemistry on a 2-chlorotrityl resin. This intermediate was esterified or amidated in solution phase. The structure-activity relationships (SAR) showed that the C-terminus acted as not only a critical pharmacophore for the substance P antagonist activities, but as an address region for the opioid agonist pharmacophore that is structurally distant from the C-terminal. Among the peptides, H-Tyr-D-Ala-Gly-Phe-Pro-Leu-Trp-NH-Bzl (3) demonstrated high binding affinities at both δ and μ receptors (Ki = 10 and 0.65 nM, respectively) with efficient agonist functional activity in the mouse isolated vas deferens (MVD) and guinea pig isolated ileum (GPI) assays (IC 50 = 50 and 13 nM, respectively). Compound 3 also showed a good antagonist activity in the GPI assay with substance P stimulation (Ke = 26 nM) and good affinity for the hNK1 receptor (Ki = 14 nM). Consequently, compound 3 is expected to be a promising and novel type of analgesic with bifunctional activities.
AB - A series of bifunctional peptides with opioid agonist and substance P antagonist bioactivities were designed with the concept of overlapping pharmacophores. In this concept, the bifunctional peptides were expected to interact with each receptor separately in the spinal dorsal horn where both the opioid receptors and the NK1 receptors were found to be expressed, to show an enhanced analgesic effect, no opioid-induced tolerance, and to provide better compliance than coadministration of two drugs. Compounds were synthesized using a two-step combinatorial method for C-terminal modification. In the method, the protected C-terminal-free carboxyl peptide, Boc-Tyr(tBu)-D-Ala-Gly Phe-Pro-Leu-Trp(Boc)-OH, was synthesized as a shared intermediate using Fmoc solid phase chemistry on a 2-chlorotrityl resin. This intermediate was esterified or amidated in solution phase. The structure-activity relationships (SAR) showed that the C-terminus acted as not only a critical pharmacophore for the substance P antagonist activities, but as an address region for the opioid agonist pharmacophore that is structurally distant from the C-terminal. Among the peptides, H-Tyr-D-Ala-Gly-Phe-Pro-Leu-Trp-NH-Bzl (3) demonstrated high binding affinities at both δ and μ receptors (Ki = 10 and 0.65 nM, respectively) with efficient agonist functional activity in the mouse isolated vas deferens (MVD) and guinea pig isolated ileum (GPI) assays (IC 50 = 50 and 13 nM, respectively). Compound 3 also showed a good antagonist activity in the GPI assay with substance P stimulation (Ke = 26 nM) and good affinity for the hNK1 receptor (Ki = 14 nM). Consequently, compound 3 is expected to be a promising and novel type of analgesic with bifunctional activities.
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U2 - 10.1021/jm070332f
DO - 10.1021/jm070332f
M3 - Article
C2 - 18266313
AN - SCOPUS:41649107460
SN - 0022-2623
VL - 51
SP - 1369
EP - 1376
JO - Journal of Medicinal Chemistry
JF - Journal of Medicinal Chemistry
IS - 5
ER -