2,8-Diazaspiro[4.5]decan-8-yl)pyrimidin-4-amine potent CCR4 antagonists capable of inducing receptor endocytosis

Abstract

A number of potent 2,8-diazaspiro[4.5]decan-8-yl)pyrimidin-4-amine CCR4 antagonists binding to the extracellular allosteric site were synthesised. (R)-N-(2,4-Dichlorobenzyl)-2-(2-(pyrrolidin-2-ylmethyl)-2,8-diazaspiro[4.5]decan-8-yl)pyrimidin-4-amine (R)-(18a) has high affinity in both the [(125)I]-TARC binding assay with a pKi of 8.8, and the [(35)S]-GTPγS functional assay with a pIC50 of 8.1, and high activity in the human whole blood actin polymerisation assay (pA2 = 6.7). The most potent antagonists were also investigated for their ability to induce endocytosis of CCR4 and were found to internalise about 60% of the cell surface receptors, a property which is not commonly shared by small molecule antagonists of chemokine receptors.

The C-C Chemokine Receptor Type 4 Is an Immunomodulatory Target of Hydroxychloroquine

“…CCR4 antagonists are used in the United States for the treatment of mycosis fungoides and Sézary disease, and used globally for the treatment of adult T-cell leukemia/lymphoma (ATCLL) and CCR4+ cutaneous T cell lymphoma (CTCL) ( Yu et al, 2007 ; FDA, 2018 ). AF-399 and compound 18a exhibit exceptional binding characteristics against CCR4 in vitro (IC50 = 2-10 and 8.1 nM, respectively) ( Bayry et al, 2008 ; Klein et al, 2017 ; Shukla et al, 2016 ). Additionally, K777 is a broad-spectrum antiviral that prevents cathepsin-mediated cell entry ( Jacobsen et al, 2000 ).…”

A Narrative Review of the State of the Art of CCR4-Based Therapies in Cutaneous T-Cell Lymphomas: Focus on Mogamulizumab and Future Treatments

“…Compound (CCR4 antagonist 18a), not to be confused with another molecule also named 18a (in the literature also known as HIV-1 inhibitor 18A, studied for its capacity to inhibit HIV-1 entry in cells expressing CCR5 [70]), was discovered by Lena Shukla et al [107]. It was found to have a high affinity for CCR4 and to induce the internalisation of about 60% of the CCR4 cell surface receptors, which is generally unusual for small molecules.…”

Exploring an Intracellular Allosteric Site of CC-Chemokine Receptor 4 from 3D Models, Probe Simulations, and Mutagenesis

“…23 The first chemotype includes basic small lipophilic antagonists (e.g., BMS-397 and Z5367428075), which are predicted to bind to the extracellular side of the receptor, partially overlapping with the orthosteric site. 21,24 The second chemotype includes arylsulfonamide compounds (e.g., AZD2098 and GSK2239633A), which bind to an intracellular site. 24−26 Despite available modulators, no CCR4-targeted small molecule modulators have been licensed yet, with GSK2239633A failing to meet clinical CCR4 inhibition thresholds.…”

“…Two chemotypes of selective CCR4 NAMs have been identified by random screening that bind to distinct receptor sites . The first chemotype includes basic small lipophilic antagonists (e.g., BMS-397 and Z5367428075), which are predicted to bind to the extracellular side of the receptor, partially overlapping with the orthosteric site. , The second chemotype includes arylsulfonamide compounds (e.g., AZD2098 and GSK2239633A), which bind to an intracellular site. − Despite available modulators, no CCR4-targeted small molecule modulators have been licensed yet, with GSK2239633A failing to meet clinical CCR4 inhibition thresholds . This highlights the importance of employing structure-based approaches to improve the ligand design outcomes for this receptor.…”