CC Chemokine Receptor 2 Antagonists Research Articles

Inducing Receptor Degradation as a Novel Approach to Target CC Chemokine Receptor 2 (CCR2).

CC chemokine receptor 2 (CCR2) has been linked to many inflammatory and immune diseases, making it a relevant drug target. Yet, all CCR2 antagonists developed so far have failed in clinical trials; thus, novel strategies are needed to target this receptor. Targeted protein degradation represents a novel approach to inhibit protein function by hijacking the cellular degradation machinery, such as the proteasome, to degrade the protein of interest. Here, we aimed to determine the amenability of CCR2 to chemically induced degradation by using a CCR2 fusion protein containing a HaloTag7 and HiBiT tag (CCR2-HaloTag-HiBiT). After characterization of the CCR2 construct, we used luminescence-based assays and immunofluorescence to quantify CCR2 levels, as well as a label-free, phenotypic assay to investigate the functional effect of CCR2 degradation. Treatment with HaloPROTAC3, which selectively degrades HaloTag fusion proteins, led to concentration- and time-dependent degradation of CCR2-HaloTag-HiBiT. HaloPROTAC3 induced degradation via the proteasome, as degradation was fully blocked with proteasomal inhibitors. Finally, functional assays showed that degradation of CCR2-HaloTag-HiBiT leads to a reduced functional response after agonist stimulation. Overall, our results indicate that CCR2 is amenable to targeted degradation, paving the way for the future development of CCR2 chemical degraders.

PSIX-7 Attenuation of Immune Allergic Response Pathways in Canines with Dermatological Problems Fed a Polyphenol-Rich Food

Abstract Pathogenesis of canine dermatological problems is mediated by multiple effector cells including lymphocytes, eosinophils, and mast cells. We have previously reported a significant increase in the gene expression of interleukin-5 receptor alpha (IL-5RA) in dogs with dermatological problemscompared with controls, as well as a modest increase in C-C chemokine receptor 3 (CCR3), IL-4 and IL-5. We now investigated whether 2 tests foods (one rich in polyphenols) would provide beneficial effects in canines with dermatological problems (n = 8) compared with controls (n = 8). Dogs were pre-fed control food for 28 days and then divided into two groups based on their age, gender and phenotype (Healthy, Derm) followed by a cross-over design. At each phase, dogs were fed for 42 days with test food 1 (TF1) and the second group was fed with a greater polyphenol content Test food 2 (TF2) for 42 days followed by a crossover. Blood samples were collected at the end of pre-feed, end of phase 1, and end of phase 2. The study was approved by IACUC and AWC, Hill’s PNC. RNA was extracted from blood collected in PAXgene tubes and gene expression was investigated using the NanoString nCounter platform. To assess the food effect, a mixed model analysis was performed using treatment (food) as a fixed effect and animal as random effect using JMPPro. TF2 fed dogs decreased pruritus scores, increased the response rate (improvement %) to 30.77% compared with dogs fed TF1. There was a significant decrease in the interleukin-5 receptor alpha (IL-5RA) in dogs fed TF2 when compared with baseline (P < 0.05). IL-5RA is a receptor expressed on eosinophils as well as committed eosinophil precursors in the bone marrow. There was also a decrease in FCRL2 in dogs fed TF2 (P < 0.05). This gene is preferentially expressed in memory B-cells and plasma cells and also involved in B-cell receptor signaling. The generation of plasma cells requires naïve B cell activation to differentiate into antibody secreting cells or memory B cells. Given the lower levels of FCRL2 with TF2, it is possible that the production of subsequent IgE is attenuated. Another signaling molecule that was significantly decreased with TF2 was the innate immune response molecule C3AR1, a receptor for Complement C3a that induces chemotaxis, granule release, as well as superoxide production. TF1 and TF2 significantly decreased CCR3, a receptor on eosinophils and basophils. CCR3 antagonists are effective in reducing allergic inflammation. Our results indicate the important role of eosinophilic allergic response in dermatological disorders in dogs. TF2 appears to have a beneficial effect in attenuating allergy-inducing signaling pathways of innate and adaptive immune responses. Targeting these molecules may be important as part of newer therapeutic approaches, including nutritional strategies, to manage dermatological problems in dogs.

Profiling CCR3 target pathways for discovering novel antagonists from natural products using label-free cell phenotypic assays

CC chemokine receptor 3 (CCR3) plays important roles in atopic dermatitis (AD) and other related allergic diseases. Activation of CCR3 receptor signaling pathways regulates the recruitment of eosinophils to related tissues, releasing inflammatory mediators and causing inflammatory responses. However, none of the known CCR3 antagonists exhibit promising efficacy in clinical trials. In this work, we sought new natural CCR3 antagonists for drug development. To construct a high-throughput screening model, we established a stably transfected CHO-K1-Gα15-CCR3 cell line, and receptor expression was demonstrated by real-time quantitative PCR, confocal detection and flow cytometry analysis. Then, we applied a label-free cell phenotyping technique to profile and deconvolute CCR3 target pathways in CHO-K1-Gα15-CCR3 cells and found that activation of CCR3 triggered the Gq-PLC-Ca2+ and MAPK-P38-ERK pathways. By in vitro and in silico experiments, we discovered a novel CCR3 antagonist emodin, with an IC50 value of 27.28 ± 1.71 μM out of 266 compounds that were identified in 15 traditional Chinese medicines used in the clinical treatment of skin diseases. Molecular docking graphically presented the binding mode of emodin on CCR3. This work reports a new approach for CCR3 antagonist screening and pathway detection and identifies a new antagonist that would benefit future drug development.

Fluorescent Ligands Targeting the Intracellular Allosteric Binding Site of the Chemokine Receptor CCR2.

Fluorescently labeled ligands are versatile molecular tools to study G protein-coupled receptors (GPCRs) and can be used for a range of different applications, including bioluminescence resonance energy transfer (BRET) assays. Here, we report the structure-based development of fluorescent ligands targeting the intracellular allosteric binding site (IABS) of the CC chemokine receptor 2 (CCR2), a class A GPCR that has been pursued as a drug target in oncology and inflammation. Starting from previously reported intracellular CCR2 antagonists, several tetramethylrhodamine (TAMRA)-labeled CCR2 ligands were designed, synthesized, and tested for their suitability as fluorescent reporters to probe binding to the IABS of CCR2. By means of these studies, we developed 14 as a fluorescent CCR2 ligand, enabling cell-free as well as cellular NanoBRET-based binding studies in a non-isotopic and high-throughput manner. Further, we show that 14 can be used as a tool for fragment-based screening approaches. Thus, our small-molecule-based fluorescent CCR2 ligand 14 represents a promising tool for future studies of CCR2 pharmacology.

Novel Piperidinyl-Azetidines as Potent and Selective CCR4 Antagonists Elicit Antitumor Response as a Single Agent and in Combination with Checkpoint Inhibitors.

The C-C chemokine receptor 4 (CCR4) is broadly expressed on regulatory T cells (Treg) as well as other circulating and tissue-resident T cells. Treg can be recruited to the tumor microenvironment (TME) through the C-C chemokines CCL17 and CCL22. Treg accumulation in the TME has been shown to dampen the antitumor immune response and is thought to be an important driver in tumor immune evasion. Preclinical and clinical data suggest that reducing the Treg population in the TME can potentiate the antitumor immune response of checkpoint inhibitors. We have developed small-molecule antagonists of CCR4, featuring a novel piperidinyl-azetidine motif, that inhibit the recruitment of Treg into the TME and elicit antitumor responses as a single agent or in combination with an immune checkpoint blockade. The discovery of these potent, selective, and orally bioavailable CCR4 antagonists, and their activity in in vitro and in vivo models, is described herein.

589 Effects of CCR4 antagonists in cutaneous T-cell lymphoma cells

CC chemokine receptor 4 (CCR4) is responsible for T-cell skin homing. It is overexpressed in type 2 helper T-cells (Th2) as well as cutaneous T-cell lymphoma (CTCL) cells. Mycosis fungoides (MF) and Sézary syndrome (SS) are two most common types of CTCL. Currently, Mogamulizumab, a humanized anti-CCR4 antibody, has been FDA-approved to treat MF and SS. However, the clinical response rates for SS patients was 30% and for MF patients was 22% and severe drug eruptions following treatment were reported. Thus, a more effective and less toxic strategy is needed for CCR4-targeted therapy. CCR4 antagonists have been studied in diseases where Th2 cells participate, such as asthma and atopic dermatitis, but little has been done for CTCL. Here, we tested two CCR4 antagonists, C021 (class I antagonist) and AZD2098 (class II antagonist), in MF derived cell line (MJ) and SS derived cell line (Hut78). The effects of two compounds on cell chemotaxis, proliferation, apoptosis, and Th2 cytokine secretion were assessed. As expected, CCR4 was highly expressed on MJ and Hut78 cells. MJ and Hut78 cells showed chemotactic responses to TARC/CCL17 and MDC/CCL22. Both C021 and AZD2098 inhibited chemotactic responses to TARC/CCL17 and MDC/CCL22 in MJ and Hut78 cells. Of note, C021 inhibited chemotaxis to CCL17 at a much lower concentration (IC50: 0.186 μM) than to CCL22 (1.3 μM) in MJ cells. AZD2098 inhibited chemotaxis to CCL17 at a much lower concentration (IC50: 0. 12 μM) than to CCL22 (0.866 μM) in Hut78 cells. Interestingly, only C021 downregulated CCR4 expression on cell surfaces. Only C021 inhibited cell proliferation, at a higher concentration (IC50: 3.21 μM in MJ cells; 5.98 μM in Hut78 cells), and induced cell apoptosis. AZD2098 had no such effect at any concentrations tested. In addition, the expressions of IL-5 and IL-13 proteins were decreased after treatment with C021 but not with AZD2098. Our results suggest that both CO21 and AZD2098 have inhibitory effects on chemotaxis of CTCL cells, but only C021 exerts other effects on CTCL cells. The in vivo study is on the way.

Structural basis for ligand modulation of the CCR2 conformational landscape

CC chemokine receptor 2 (CCR2) is a part of the chemokine receptor family, an important class of therapeutic targets. These class A G-protein coupled receptors (GPCRs) are involved in mammalian signaling pathways and control cell migration toward endogenous CC chemokine ligands, named for the adjacent cysteine motif on their N terminus. Chemokine receptors and their associated ligands are involved in a wide range of diseases and thus have become important drug targets. CCR2, in particular, promotes the metastasis of cancer cells and is also implicated in autoimmunity-driven type-1 diabetes, diabetic nephropathy, multiple sclerosis, asthma, atherosclerosis, neuropathic pain, and rheumatoid arthritis. Although promising, CCR2 antagonists have been largely unsuccessful to date. Here, we investigate the effect of an orthosteric and an allosteric antagonist on CCR2 dynamics by coupling long-timescale molecular dynamics simulations with Markov-state model theory. We find that the antagonists shift CCR2 into several stable inactive conformations that are distinct from the crystal structure conformation and disrupt a continuous internal water and sodium ion pathway, preventing transitions to an active-like state. Several metastable conformations present a cryptic drug-binding pocket near the allosteric site that may be amenable to targeting with small molecules. Without antagonists, the apo dynamics reveal intermediate conformations along the activation pathway that provide insight into the basal dynamics of CCR2 and may also be useful for future drug design.

The regulation and importance of monocyte chemoattractant protein-1.

Monocyte chemoattractant protein (MCP)-1, a chemokine regulating monocyte chemotaxis and T-lymphocyte differentiation by binding to the CC chemokine receptor 2 (CCR2), plays a crucial role in the pathogenesis of inflammatory diseases, atherosclerosis and cancer. This review summarizes the current knowledge on the regulation and importance of the MCP-1/CCR2 axis, focusing on the therapeutic potential of its inhibition. Differential modulation of MCP-1 and CCR2 lead to downstream activation pathways, pathogenetic to differing disease conditions characterized by dysregulated monocyte/macrophage tissue recruitment. Pharmacological targeting of the MCP-1/CCR2 axis has led to selective MCP-1/CCR2 antagonists that have now entered phase I/II clinical trials for the treatment of inflammatory diseases, atherosclerosis and cancer. The pleiotropic nonselective MCP-1/CCR2 inhibition by current pharmacological agents is thought to contribute to their anti-inflammatory and antiatherosclerotic effects that is also seen for nutraceutical compounds such as curcumin. MCP-1 has a critical role in regulating chemotaxis both in health and disease, with increasing interest in its pharmacological inhibition. However, the therapeutic efficacy and safety of targeting the MCP-1/CCR2 axis is still in evolution.

The C-C Chemokines CCL17 and CCL22 and Their Receptor CCR4 in CNS Autoimmunity.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). It affects more than two million people worldwide, mainly young adults, and may lead to progressive neurological disability. Chemokines and their receptors have been shown to play critical roles in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a murine disease model induced by active immunization with myelin proteins or transfer of encephalitogenic CD4+ T cells that recapitulates clinical and neuropathological features of MS. Chemokine ligand-receptor interactions orchestrate leukocyte trafficking and influence multiple pathophysiological cellular processes, including antigen presentation and cytokine production by dendritic cells (DCs). The C-C class chemokines 17 (CCL17) and 22 (CCL22) and their C-C chemokine receptor 4 (CCR4) have been shown to play an important role in homeostasis and inflammatory responses. Here, we provide an overview of the involvement of CCR4 and its ligands in CNS autoimmunity. We review key clinical studies of MS together with experimental studies in animals that have demonstrated functional roles of CCR4, CCL17, and CCL22 in EAE pathogenesis. Finally, we discuss the therapeutic potential of newly developed CCR4 antagonists and a humanized anti-CCR4 antibody for treatment of MS.

Identification of pyrazolopyrimidine arylsulfonamides as CC-chemokine receptor 4 (CCR4) antagonists

A novel 4-aminoindazole sulfonamide hit (13) was identified as a human CCR4 antagonists from testing a focussed library of compounds in the primary GTPγS assay. Replacing the indazole core with a pyrazolopyrimidine, and introduction of a methoxy group adjacent to the sulfonamide substituent, resulted in the identification of pyrazolopyrimidine 37a, which exhibited good binding affinity in the GTPγS assay (pIC50=7.2), low lipophilicity (clogP=2.2, chromlogD7.4=2.4), high LE (0.41), high solubility (CLND solubility ≥581µM), and an excellent PK profile in both the rat (F=62%) and the dog (F=100%). Further SAR investigation of the pyrazolopyrimidine suggested that substitution at N1 is tolerated, providing a suitable vector to modulate the properties, and increase the potency in a lead optimisation campaign.

A novel CCR2 antagonist inhibits atherogenesis in apoE deficient mice by achieving high receptor occupancy

CC Chemokine Receptor 2 (CCR2) and its endogenous ligand CCL2 are involved in a number of diseases, including atherosclerosis. Several CCR2 antagonists have been developed as potential therapeutic agents, however their in vivo clinical efficacy was limited. In this report, we aimed to determine whether 15a, an antagonist with a long residence time on the human CCR2, is effective in inhibiting the development of atherosclerosis in a mouse disease model. First, radioligand binding assays were performed to determine affinity and binding kinetics of 15a on murine CCR2. To assess the in vivo efficacy, western-type diet fed apoE−/− mice were treated daily with 15a or vehicle as control. Treatment with 15a reduced the amount of circulating CCR2+ monocytes and the size of the atherosclerotic plaques in both the carotid artery and the aortic root. We then showed that the long pharmacokinetic half-life of 15a combined with the high drug concentrations ensured prolonged CCR2 occupancy. These data render 15a a promising compound for drug development and confirms high receptor occupancy as a key parameter when targeting chemokine receptors.

Eosinophil chemotaxis assay in nasal polyps by using a novel optical device EZ-TAXIScan: Role of CC-chemokine receptor 3

BackgroundThe chemokine receptor, CC-chemokine receptor 3 (CCR3), and its major ligands, eotaxin, RANTES, and MCP-4, are involved in eosinophil chemotaxis. It is thought that CCR3 plays an important role in the recruitment and activation of eosinophils in nasal polyposis. We examined nasal polyp extract-induced eosinophil chemotaxis and the effect of a CCR3 antagonist using EZ-TAXIScan, a novel real-time chemotaxis assay device. MethodsNasal polyps were obtained from chronic rhinosinusitis (CRS) patients during surgery. The polyps were homogenized and eotaxin levels in the extracts were measured. Eosinophils were purified from human peripheral blood by the CD16 negative selection method. Nasal polyp extract-induced eosinophil chemotaxis, with or without CCR3 antagonist, was assessed by EZ-TAXIScan. ResultsThere was a significant positive correlation between the eosinophil counts in nasal polyp and eotaxin levels in the nasal polyp extracts. Using EZ-TAXIScan, eosinophil chemotactic responses were observed following stimulation with nasal polyp extracts. There was a significant positive correlation between the chemotactic index toward the nasal polyp extracts and their eotaxin levels. Nasal polyp extract-induced chemotaxis was completely inhibited by CCR3 antagonist but not by chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) antagonist which inhibited PGD2-induced eosinophil chemotaxis. ConclusionsThe CCR3 pathway may play an important role in the pathogenesis of eosinophil recruitment in nasal polyps through selective eosinophil chemotaxis.

Lead identification of benzimidazolone and azabenzimidazolone arylsulfonamides as CC-chemokine receptor 4 (CCR4) antagonists

A knowledge-based library of 2,3-dichlorophenylsulfonyl derivatives of commercially available aryl amines was synthesised and screened as human CCR4 antagonists, in order to identify a suitable hit for the start of a lead-optimisation programme. Hits were required to be more potent than an existing indazole series, have better physicochemical properties (clogP <3.5, chrom logD7.4 <5.3 and CLND solubility >116μg/mL), and be stable to acid and light. The benzimidazol-2-one core was identified as a hit suitable for further investigation. Substitution at N1 with small alkyl groups was tolerated; however, these analogues were inactive in the whole blood assay (pA2 <5). Azabenzimidazolone analogues were all found to be active, with compound 38 exhibiting whole blood activity of 6.1, low molecular weight (389) and chrom logD7.4 (2.4), high LE (0.43), and solubility (152μg/mL). In addition, 38 had human serum albumin binding of around 93% and met all the criteria for progression to lead optimisation.

Lead identification and structure–activity relationships of heteroarylpyrazole arylsulfonamides as allosteric CC-chemokine receptor 4 (CCR4) antagonists

A knowledge-based library of aryl 2,3-dichlorophenylsulfonamides was synthesised and screened as human CCR4 antagonists, in order to identify a suitable hit for the start of a lead-optimisation programme. X-ray diffraction studies were used to identify the pyrazole ring as a moiety that could bring about intramolecular hydrogen bonding with the sulfonamide NH and provide a clip or orthogonal conformation that was believed to be the preferred active conformation. Replacement of the core phenyl ring with a pyridine, and replacement of the 2,3-dichlorobenzenesulfonamide with 5-chlorothiophenesulfonamide provided compound 33 which has excellent physicochemical properties and represents a good starting point for a lead optimisation programme. Electronic structure calculations indicated that the preference for the clip or orthogonal conformation found in the small molecule crystal structures of 7 and 14 was in agreement with the order of potency in the biological assay.

Design, Synthesis and Biological Activities of a Series of Piperazine Pyrimidine as CCR4 Antagonists

CC chemokine receptor 4(CCR4) is a pivotal factor in the development of allergic inflammations,such as asthma,dermatitis and rhinitis.CCR4 antagonists have a huge potential in the therapeutics of the allergic diseases,and BMS-397 is the most potent CCR4 antagonists in the reported compounds.The structureactivity relationship of BMS-397 was studied and the large influence of the groups of pyridine and piperidine on the activity led us to modify these two sites.A series of piperazine pyrimidine derivatives was designed and synthesized.Their structures were characterized by1H NMR,13C NMR,MS and elemental analysis.The activities of all the newly synthesized compounds were evaluated using a chemotaxis inhibition assay.The results of biological activity experiment show that compound 8a was more potent than BMS-397.In the murine rhinitis model,budesonide was used as the calibration or comparison standard to assess the relative efficacy of compound 8a.The results show that compound 8a was more effective than budesonide,revealed excellent affinity to N-terminal of CCR4,and the apparent binding constant of CZE experiment result was(3.6179 ± 0.5976) × 104L / mol.

Design and Synthesis of Tri‐substituted Chiral Pyrrolidin‐2‐one Derivatives as CCR4 Antagonists

AbstractA series of tri‐substituted chiral pyrrolidin‐2‐one derivatives have been designed and synthesized as CC chemokine receptor 4 (CCR4) antagonists. The structure of CCR4 was built by homology modeling. Asymmetric synthesis was applied to synthesize the R,R configuration chiral pyrrolidin‐2‐one scaffold. The stereoisomeric configurations of the compounds were identified by 2D 1H‐1H COSY spectroscopy and 1D NOESY spectroscopy. This method was more economical and convenient than traditional X‐ray single crystal diffraction. In addition, the interactions between these compounds and the N‐terminal extracellular tail of CCR4 were studied using capillary zone electrophoresis. The CCR4 chemotaxis inhibition effect was tested in CCR4‐transfected HEK293 cells. Several compounds showed potent activities as CCR4 antagonists. Among these compounds, 1c is the most active one. Its apparent binding constant of CZE experiment result is (1.569±0.11)×105 L·mol−1, and its percentage inhibition of the HEK293/CCR4 cells migration with the concentration of 1 µmol·L−1 in DMSO is 59%. And compound 1f has slightly higher affinity to N‐terminal of CCR4 according to its apparent binding constant than 1b because of the introduced ester linkage. Further studies on the mechanism of these compounds are in progress.

Interactions Between N-Terminal Extracellular Tail of CCR4 and Natural Products of Licorice Using Capillary Electrophoresis

Licorice is gaining popularity because of its significant biological anti-inflammatory activity, while CC chemokine receptor 4 (CCR4) has been identified as a potentially important drug target for the treatment of inflammatory diseases. Capillary electrophoresis was developed for screening for the first time of CCR4 antagonists from natural products of licorice. The interactions between natural products of licorice and ML40, the equivalent peptide derived from the N-terminal of CCR4, were determined. Twenty-eight ingredients were isolated and the results showed that ten of them interacted with ML40 compared with the positive control S009. The binding constants of the compounds to ML40 were calculated and the binding constant of liquiritin apioside (LA) was the largest among them (3.636 ± 0.2185) × 104 M−1. The CCR4 antagonisms of the compounds that showed strong integration with ML40 were also confirmed by chemotaxis inhibition in which they displayed different degrees of inhibition to CCL22/CCL17-induced HEK293 chemotaxis. The methodology presented could be applied to automated high-throughput screening of potential antagonists of CCR4. This study provided the potential rationale for the development of anti-inflammatory compounds from natural products of licorice.

Synthesis and Structure–Activity Relationships of Indazole Arylsulfonamides as Allosteric CC-Chemokine Receptor 4 (CCR4) Antagonists

A series of indazole arylsulfonamides were synthesized and examined as human CCR4 antagonists. Methoxy- or hydroxyl-containing groups were the more potent indazole C4 substituents. Only small groups were tolerated at C5, C6, or C7, with the C6 analogues being preferred. The most potent N3-substituent was 5-chlorothiophene-2-sulfonamide. N1 meta-substituted benzyl groups possessing an α-amino-3-[(methylamino)acyl]-group were the most potent N1-substituents. Strongly basic amino groups had low oral absorption in vivo. Less basic analogues, such as morpholines, had good oral absorption; however, they also had high clearance. The most potent compound with high absorption in two species was analogue 6 (GSK2239633A), which was selected for further development. Aryl sulfonamide antagonists bind to CCR4 at an intracellular allosteric site denoted site II. X-ray diffraction studies on two indazole sulfonamide fragments suggested the presence of an important intramolecular interaction in the active conformation.

Development of 3D-pharmacophore model followed by successive virtual screening, molecular docking and ADME studies for the design of potent CCR2 antagonists for inflammation-driven diseases

In order to elucidate the essential structural features for CC chemokine receptor 2 (CCR2) antagonism, 3D-pharmacophore hypotheses were built based on a set of known compounds from the literature. The hypotheses were developed with the aid of HypoGen module within Discovery Studio 2.5 program. Multiple validation approaches provided the confidence in utilising the predictive pharmacophore models developed in this study. The most predictive pharmacophore model (Hypo1) was found to be statistically significant along with its ability to predict activities of the known CCR2 antagonists in the training and test set with high correlation coefficient. The best model was then used as a 3D search query in the virtual screening of chemical databases including ChemDiv and MiniMaybridge. Lipinski's rule of five and molecular docking studies were applied to the screened hits for retrieving potential lead compounds. Eight hits showed better in silico CCR2-binding affinities than the reported CCR2 antagonists, along with good absorption, distribution, metabolism and excretion profiles. The current 3D-quantitative structure–activity relationship (QSAR) pharmacophore modelling and molecular docking studies attempt to elucidate QSAR for CCR2 antagonism and identify novel potent CCR2 antagonist scaffolds.

Design and Synthesis of a Series of Pyrido[2,3-d]pyrimidine Derivatives as CCR4 Antagonists

A series of pyrido[2,3-d]pyrimidine derivatives were designed and synthesized based on known CC chemokine receptor 4 (CCR4) antagonists. The activities of all the newly synthesized compounds were evaluated using a chemotaxis inhibition assay. Compound 6b was proven to be a potent CCR4 antagonist that can block cell chemotaxis induced by macrophage-derived chemokine (MDC), thymus and activation regulated chemokine (TARC), and CKLF1, the natural ligands of CCR4. In addition, compound 6b is more effective than budesonide in the murine rhinitis model. The intravenous injection LD50 of compound 6b is 175 mg/kg and the oral LD50 is greater than 2,000 mg/kg.