Side chain effect in the modulation of αβ/αβ integrin activity via clickable isoxazoline-RGD-mimetics: development of molecular delivery systems.

Construction of small molecule ligand (SML) based delivery systems has been performed starting from a polyfunctionalized isoxazoline scaffold, whose αβ and αβ integrins' potency has been already established. The synthesis of this novel class of ligands was obtained by conjugation of linkers to the heterocyclic core via Huisgen-click reaction, with the aim to use them as "shuttles" for selective delivery of diagnostic agents to cancer cells, exploring the effects of the side chains in the interaction with the target. Compounds 17b and 24 showed excellent potency towards αβ integrin acting as selective antagonist and agonist respectively.

DS-70, a novel and potent α integrin antagonist, is an effective treatment for experimental allergic conjunctivitis in guinea pigs.

Background And Purpose: Allergic conjunctivitis is an eye inflammation that involves the infiltration of immune cells into the conjunctiva via cell surface-adhesion receptors, such as integrin α β . These receptors interact with adhesion molecules expressed on the conjunctival endothelium and may be a target to treat this disease. We synthesized DS-70, a novel α/β-peptidomimetic α integrin antagonist, to prevent the conjunctival infiltration of immune cells and clinical symptoms in a model of allergic conjunctivitis.

Selective detection of α4β1 integrin (VLA-4)-expressing cells using peptide-functionalized nanostructured materials mimicking endothelial surfaces adjacent to inflammatory sites.

Persistent accumulation of immune cells mediated by α4β1 integrin (VLA-4) is a hallmark of the inflammatory diseases and of chronic inflammation observed in the affected tissues of autoimmune diseases. Aiming at exploring new methods for monitoring the course of the inflammatory processes, we designed the first peptide-functionalized nanostructured devices capable to mimic the high-density multivalency binding between the α4β1 integrin-expressing cells and the ligands overexpressed on the endothelial surfaces, in the proximity of the sites of inflammation. Specifically, we describe the first examples of monolayers constituted by dye-loaded zeolite L crystals, coated with α4β1 integrin peptide ligands, and we analyze the adhesion of model Jurkat cells in comparison to non-α4β1 integrin-expressing cells.

New β-Lactam Derivatives Modulate Cell Adhesion and Signaling Mediated by RGD-Binding and Leukocyte Integrins.

A novel series of β-lactam derivatives that was designed and synthesized to target RGD-binding and leukocyte integrins is reported. The compound library was evaluated by investigating the effects on integrin-mediated cell adhesion and cell signaling in cell lines expressing αβ, αβ, αβ, αβ, αβ, αβ, and αβ integrins. SAR analysis of the new series of azetidinones enabled the recognition of structural elements associated with integrin selectivity.

5-aminomethyloxazolidine-2,4-dione hybrid α/β-dipeptide scaffolds as inductors of constrained conformations: Applications to the synthesis of integrin antagonists.

Peptidomimetics represent an attractive starting point for drug discovery programs; in particular, peptidomimetics that result from the incorporation of a heterocycle may take advantage of increased enzymatic stability and higher ability to reproduce the bioactive conformations of the parent peptides, resulting in enhanced therapeutic potential. Herein, we present mimetics of the α4β1 integrin antagonist BIO1211 (MPUPA-Leu-Asp-Val-Pro-OH), containing a aminomethyloxazolidine-2,4-dione scaffold (Amo). Interestingly, the retro-sequences PhCOAsp(OH)-Amo-APUMP including either (S)- or (R)-configured Amo displayed significant ability to inhibit the adhesion of α4β1 integrin expressing cells, and remarkable stability in mouse serum.

Dehydro-β-proline Containing α4β1 Integrin Antagonists: Stereochemical Recognition in Ligand-Receptor Interplay.

A novel class of dehydro-β-proline-containing peptidomimetics, designed to be effective as α4β1 integrin ligands, has been developed on the basis of the fundamental requirements for the interactions of these transmembrane receptors with bioactive ligands. Dehydro-β-proline ring has been synthesized through an original pathway, involving ring closing metathesis of a diallylamino derivative. The synthesized products showed to be effective and selective as α4β1 integrin antagonists and displayed IC50 values in the nanomolar range in cell adhesion inhibition assays and in VCAM-1-induced phosphorylation of extracellular-signal-regulated kinases.

Targeting integrins αvβ3 and α5β1 with new β-lactam derivatives.

The αvβ3 and α5β1 integrins are widely expressed in different cancer types and recognize the tripeptide Arg-Gly-Asp (RGD) motif present in several extracellular matrix proteins. We report here the design, synthesis and biological activity of some new β-lactam derivatives specifically designed to target integrins. The new molecules contain the azetidinone as the only cyclic framework armed with carboxylic acid and amine terminals spaced from 9 to 14 atoms to switch on recognition by integrins.

Synthesis and assay of retro-α4β1 integrin-targeting motifs.

In recent years, several research groups proposed new peptidomimetic antagonists of integrins αvβ3, α5β1, αIIbβ3, αvβ6, αvβ5, etc. based on retro sequences of the classic integrin-binding motif RGD. The retro strategy is still largely ignored for the non-RGD-binding α4β1 integrin.

Modulation of αvβ₃- and α₅β₁-integrin-mediated adhesion by dehydro-β-amino acids containing peptidomimetics.

A novel class of low molecular weight ligands of αvβ₃ and α₅β₁ integrins, that possess a dehydro-β-amino acid as conformationally constrained core, linked to the pharmacophoric moieties mimicking the RGD recognition sequence, have been synthesized through a very simple protocol. Cell adhesion assays and integrin-mediated signaling activation experiments suggested a good affinity of these compounds toward both integrin receptors. Moreover, further elongation with two glycine units allowed to obtain an excellent dual inhibitor.

Therapeutic targeting of eosinophil adhesion and accumulation in allergic conjunctivitis.

Considerable evidence indicates that eosinophils are important effectors of ocular allergy. Increased worldwide prevalence of allergic eye pathologies has stimulated the identification of novel drug targets, including eosinophils and adhesion molecules. Accumulation of eosinophils in the eye is a key event in the onset and maintenance of allergic inflammation and is mediated by different adhesion molecules.

REST is up-regulated by epidermal growth factor in HeLa cells and inhibits apoptosis by influencing histone H3 acetylation.

REST (repressor element 1-silencing transcription factor) is a transcription factor that recruits histone deacetylases to silence gene transcription. REST appears to play a paradoxical role in cancer cells: it exhibits tumor suppressor activity or promotes tumorigenesis, depending upon the setting. The extracellular signaling molecules that control REST gene expression in cancer cells remain poorly understood.

Development of isoxazoline-containing peptidomimetics as dual αvβ3 and α5β1 integrin ligands.

Isoxazoline-containing peptidomimetics, designed to be effective α(v)β(3) and α(5)β(1) integrin ligands, were synthesized through an original procedure involving N,O-bis(trimethylsilyl)hydroxyamine conjugate addition to alkylidene acetoacetates, followed by intramolecular hemiketalization. To mimic the RGD recognition sequence, basic and acidic terminal appendages were introduced, and the final products were tested in cell adhesion inhibition assays. All the synthesized compounds proved to be excellent ligands for both integrin receptors, and a strong influence on intracellular signaling and phosphorylation pathways was demonstrated by evaluation of fibronectin-induced phosphorylation of ERK.