Characterisation of a novel, high affinity and selective αvβ6 integrin RGD-mimetic radioligand

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• 作者：Eleanor R. Hall ; Lloyd I. Bibby ; Robert J. Slack ; ^{Robert.X.Slack@gsk.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：αvβ6 ; alpha-v beta-6 ; RGD ; arginyl-glycinyl-aspartic acid ; CHAPS ; 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate ; DPU ; Discovery Performance Unit ; DMSO ; dimethyl sulphoxide ; ELISA ; enzyme-linked immunosorbent assay ; FCS ; foetal calf serum ; HEPES ; 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid ; LAP1 ; latency associated peptide-1 ; LS ; liquid scintillation ; NSB ; non-specific binding ; TGFβ1 ; transforming growth factor-β1 ; tLAP ; truncated LAP
• 刊名：Biochemical Pharmacology
• 出版年：2016
• 出版时间：1 October 2016
• 年：2016
• 卷：117
• 期：Complete
• 页码：88-96
• 全文大小：972 K

文摘

The alpha-v beta-6 (αvβ6) integrin has been identified as playing a key role in the activation of transforming growth factor-β (TGFβ) that is hypothesised to be pivotal in the development of cancer and fibrotic diseases. Therefore, the αvβ6 integrin is an attractive therapeutic target for these debilitating diseases and a drug discovery programme to identify small molecule αvβ6 selective arginyl-glycinyl-aspartic acid (RGD)-mimetics was initiated within GlaxoSmithKline. The primary aim of this study was to pharmacologically characterise the binding to αvβ6 of a novel clinical candidate, compound 1, using a radiolabelled form.

Radioligand binding studies were completed with [³H]compound 1 against the human and mouse soluble protein forms of αvβ6 to determine accurate affinity estimates and binding kinetics. The selectivity of compound 1 for the RGD integrin family was also determined using saturation binding studies (αvβ1, αvβ3, αvβ5, αvβ8, α5β1 and α8β1 integrins) and fibrinogen-induced platelet aggregation (αIIbβ3 integrin). In addition, the relationship between divalent metal cation type and concentration and αvβ6 RGD site binding was also investigated.

Compound 1 has been demonstrated to bind with extremely high affinity and selectivity for the αvβ6 integrin and has the potential as a clinical tool and therapeutic for investigating the role of αvβ6 in a range of disease states both pre-clinically and clinically. In addition, this is the first study that has successfully applied radioligand binding to the RGD integrin field to accurately determine the affinity and selectivity profile of a small molecule RGD-mimetic.