Molecular requirements for inhibition of the chemokine receptor CCR8--probe-dependent allosteric interactions

TY - JOUR

T1 - Molecular requirements for inhibition of the chemokine receptor CCR8--probe-dependent allosteric interactions

AU - Rummel, Pia Cwarzko

AU - Arfelt, K N

AU - Baumann, L

AU - Jenkins, T J

AU - Thiele, S

AU - Lüttichau, H R

AU - Johnsen, A

AU - Pease, J

AU - Ghosh, S

AU - Kolbeck, R

AU - Rosenkilde, M M

N1 - © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

PY - 2012/11

Y1 - 2012/11

N2 - BACKGROUND AND PURPOSE Here we present a novel series of CCR8 antagonists based on a naphthalene-sulfonamide structure. This structure differs from the predominant pharmacophore for most small-molecule CC-chemokine receptor antagonists, which in fact activate CCR8, suggesting that CCR8 inhibition requires alternative structural probes. EXPERIMENTAL APPROACH The compounds were tested as inverse agonists and as antagonists against CCL1-induced activity in Gαi signalling and chemotaxis. Furthermore, they were assessed by heterologous competition binding against two radiolabelled receptor ligands: the endogenous agonist CCL1 and the virus-encoded antagonist MC148. KEY RESULTS All compounds were highly potent inverse agonists with EC50 values from 1.7 to 23 nM. Their potencies as antagonists were more widely spread (EC50 values from 5.9 to 1572 nM). Some compounds were balanced antagonists/inverse agonists whereas others were predominantly inverse agonists with >100-fold lower potency as antagonists. A correspondingly broad range of affinities, which followed the antagonist potencies, was disclosed by competition with [125I]-CCL1 (Ki 3.4-842 nM), whereas the affinities measured against [125I]-MC148 were less widely spread (Ki 0.37-27 nM), and matched the inverse agonist potencies. CONCLUSION AND IMPLICATIONS Despite highly potent and direct effects as inverse agonists, competition-binding experiments against radiolabelled agonist and tests for antagonism revealed a probe-dependent allosteric effect of these compounds. Thus, minor chemical changes affected the ability to modify chemokine binding and action, and divided the compounds into two groups: predominantly inverse agonists and balanced antagonists/inverse agonists. These studies have important implications for the design of new inverse agonists with or without antagonist properties.

AB - BACKGROUND AND PURPOSE Here we present a novel series of CCR8 antagonists based on a naphthalene-sulfonamide structure. This structure differs from the predominant pharmacophore for most small-molecule CC-chemokine receptor antagonists, which in fact activate CCR8, suggesting that CCR8 inhibition requires alternative structural probes. EXPERIMENTAL APPROACH The compounds were tested as inverse agonists and as antagonists against CCL1-induced activity in Gαi signalling and chemotaxis. Furthermore, they were assessed by heterologous competition binding against two radiolabelled receptor ligands: the endogenous agonist CCL1 and the virus-encoded antagonist MC148. KEY RESULTS All compounds were highly potent inverse agonists with EC50 values from 1.7 to 23 nM. Their potencies as antagonists were more widely spread (EC50 values from 5.9 to 1572 nM). Some compounds were balanced antagonists/inverse agonists whereas others were predominantly inverse agonists with >100-fold lower potency as antagonists. A correspondingly broad range of affinities, which followed the antagonist potencies, was disclosed by competition with [125I]-CCL1 (Ki 3.4-842 nM), whereas the affinities measured against [125I]-MC148 were less widely spread (Ki 0.37-27 nM), and matched the inverse agonist potencies. CONCLUSION AND IMPLICATIONS Despite highly potent and direct effects as inverse agonists, competition-binding experiments against radiolabelled agonist and tests for antagonism revealed a probe-dependent allosteric effect of these compounds. Thus, minor chemical changes affected the ability to modify chemokine binding and action, and divided the compounds into two groups: predominantly inverse agonists and balanced antagonists/inverse agonists. These studies have important implications for the design of new inverse agonists with or without antagonist properties.

KW - Animals

KW - Binding Sites

KW - Binding, Competitive

KW - COS Cells

KW - Cercopithecus aethiops

KW - Chemokine CCL1

KW - Chemokines, CC

KW - Ligands

KW - Naphthalenes

KW - Receptors, CCR8

KW - Viral Proteins

U2 - 10.1111/j.1476-5381.2012.02076.x

DO - 10.1111/j.1476-5381.2012.02076.x

M3 - Journal article

C2 - 22708643

SN - 0007-1188

VL - 167

SP - 1206

EP - 1217

JO - British Journal of Pharmacology

JF - British Journal of Pharmacology

IS - 6

ER -