Ligand Binding Analysis for Human α5β1 Integrin:  Strategies for Designing New α5β1 Integrin Antagonists

Marinelli, Luciana; Meyer, Axel; Heckmann, Dominik; Lavecchia, Antonio; Novellino, Ettore; Kessler, Horst

doi:10.1021/jm040224i

Cited by 75 publications

(79 citation statements)

References 34 publications

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“…It is overexpressed in angiogenic endothelial cells but also in astrocytomas and glioblastomas (5) and may represent a new anticancer target. To date, few molecules acting as a 5 h 1 antagonists have been developed, with SJ749 being the most selective nonpeptidic a 5 h 1 antagonist described thus far (6)(7)(8)(9). SJ749 was designed as a fibronectin adhesion antagonist that specifically inhibits a 5 h 1 -mediated cell adhesion to fibronectin.…”

Section: Introductionmentioning

confidence: 99%

The Small α5β1 Integrin Antagonist, SJ749, Reduces Proliferation and Clonogenicity of Human Astrocytoma Cells

Maglott¹,

Bartik²,

Cosgun

et al. 2006

Cancer Research

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The potential role of A 5 B 1 integrins in cancer has recently attracted much interest. However, few A 5 B 1 -selective antagonists have been developed compared with other integrins. The most specific nonpeptidic A 5 B 1 antagonist described thus far, SJ749, inhibits angiogenesis by affecting adhesion and migration of endothelial cells. We investigated the effects of SJ749 in two human astrocytoma cell lines, A172 and U87, which express different levels of A 5 B 1 . SJ749 dose-dependently inhibited adhesion of both cell types on fibronectin. Application of SJ749 to spread cells led to formation of nonadherent spheroids for A172 cells but had no effect on U87 cell morphology. SJ749 also reduced proliferation of A172 cells due to a long lasting G 0 -G 1 arrest, whereas U87 cells were only slightly affected. However, under nonadherent culture conditions (soft agar), SJ749 significantly reduced the number of colonies formed only by U87 cells. As U87 cells express more A 5 B 1 than A172 cells, we specifically examined the effect of SJ749 on A172 cells overexpressing A 5 . Treatment of A 5 -A172 cells with SJ749 decreased colony formation similarly to that observed in U87 cells. Therefore, in nonadherent conditions, the effect of SJ749 on tumor cell growth characteristics depends on the level of A 5 B 1 expression. Our study highlights the importance of A 5 B 1 as an anticancer target and shows for the first time that a small nonpeptidic A 5 B 1 -specific antagonist affects proliferation of tumor cells. (Cancer Res 2006; 66(12): 6002-7)

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Section: Introductionmentioning

confidence: 99%

The Small α5β1 Integrin Antagonist, SJ749, Reduces Proliferation and Clonogenicity of Human Astrocytoma Cells

Maglott¹,

Bartik²,

Cosgun

et al. 2006

Cancer Research

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“…Erste Anhaltspunkte für die Struktur neuer möglicher a5b1-Liganden lieferte das Homologiemodell des a5b1-Integrins im Komplex mit dem kürzlich publizierten Liganden SJ749. [2,16] Die große ¾hnlichkeit zwischen den Integrinen avb3 und a5b1 (53 % Übereinstimmung von av mit a5, 55 % Über-einstimmung in der Kopfgruppe von b3 mit b1) sollte es ermöglichen, die Qualität unseres Modells durch die Synthese einer Bibliothek maßgeschneiderter Liganden zu prüfen. Analog zu anderen RGD-ähnlichen Liganden enthalten unsere Verbindungen ein Carboxylat und eine basische funktionelle Gruppe im Abstand von ca.…”

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“…Ein so erstelltes Homologiemodell ist für rationales Wirkstoffdesign geeignet. [1] Hier beschreiben wir die Anwendung unseres kürzlich veröffent-lichten Homologiemodells des a5b1-Integrins [2] auf die Entwicklung hoch aktiver (bis in den subnanomolaren Bereich) Liganden mit Selektivität gegen das eng verwandte avb3-Integrin. Basierend auf Strukturüberlegungen wurde die Selektivität in beide Richtungen hin verändert.…”

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Rationales Design von hoch aktiven und selektiven Liganden für α5β1‐ und αvβ3‐Integrine

et al. 2007

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Integrine sind heterodimere Zelladhäsionsrezeptoren, die an einer Vielzahl pathologischer Prozesse wie der Metastasierung von Tumoren, Thrombose, Entzündungen und Osteoporose beteiligt sind.[3] Sie sind daher seit geraumer Zeit wichtige Ziele in der pharmazeutischen Industrie.[4] Seit Brooks et al. berichteten, dass das von uns entwickelte[5a] das die Integrine avb3 und avb5 bindet, durch Angiogenese-Inhibierung das Tumorwachstum hemmt, [6] wurden viele avb3-Liganden entwickelt, von denen einige bereits klinische Tests durchlaufen.[7] So befindet sich das cyclische, N-methylierte Pentapeptid c(-RGDf[NMe]V-) [5b] als "Cilengitide" derzeit in der klinischen Phase II für die Behandlung von Glioblastomen.In jüngster Zeit wurde die proangiogenetische Wirkung der av-Integrine durch Knock-out-Experimente ernsthaft infrage gestellt. So zeigten av-Knock-out-Mäuse verstärkt Angiogenese, während b3/b5-defizitäre Mäuse keine signifikanten Veränderungen aufwiesen. [8,9] Dagegen konnte die proangiogenetische Funktion des a5b1-Rezeptors klar nachgewiesen werden, was den Forschungsschwerpunkt immer mehr Richtung a5b1 verlagerte. [10,11] Anders als im Fall der Integrine avb3 und aIIbb3, deren aufgeklärte Kristallstrukturen detaillierte Einblicke in die Bindung von Liganden ermöglichten, [12,13] gibt es vom a5b1-Integrin nur unzureichende Daten zu Struktur und Bindungsverhalten. [14] Der Mangel an Liganden [15,16] für das a5b1-Integrin bewog uns, diesen Rezeptor näher zu untersuchen. Erste Anhaltspunkte für die Struktur neuer möglicher a5b1-Liganden lieferte das Homologiemodell des a5b1-Integrins im Komplex mit dem kürzlich publizierten Liganden SJ749. [2,16] Die große ¾hnlichkeit zwischen den Integrinen avb3 und a5b1 (53 % Übereinstimmung von av mit a5, 55 % Über-einstimmung in der Kopfgruppe von b3 mit b1) sollte es ermöglichen, die Qualität unseres Modells durch die Synthese einer Bibliothek maßgeschneiderter Liganden zu prüfen. Analog zu anderen RGD-ähnlichen Liganden enthalten unsere Verbindungen ein Carboxylat und eine basische funktionelle Gruppe im Abstand von ca. 13 . Beim Vergleich beider Bindungstaschen fallen zwei Regionen auf, deren Mutationen zum Erreichen von Selektivität zwischen a5b1-und avb3-Integrinen genutzt werden können: In der bUntereinheit sind (b3)-Arg 214 und (b3)-Arg 216 durch (b1)-Gly 217 bzw. (b1)-Leu 219 ersetzt, was zu einer Aufweitung der a5b1-Bindungstasche führt (die wichtigen Mutationen sind in Abbildung 1 hervorgehoben). Dadurch sollte a5b1 im Unterschied zu avb3 Liganden tolerieren, an deren Grundgerüst sich sterisch anspruchsvolle Reste befinden. Des Weiteren sorgt die Mutation von (av)-Asp 150 zu (a5)-Ala 159 für eine schwächer saure Bindungsstelle in der a5-Untereinheit, deren Gestalt zusätzlich dadurch verändert ist, dass (av)-Thr 212 gegen (a5)-Gln 221 ausgetauscht ist. Damit könnte auch durch eine ¾nderung der basischen Gruppe Selektivität induziert werden.Basierend auf dem Tyrosingrundgerüst, das bereits erfolgreich in Integrinliganden zum Einsatz gekommen war, [17] wurde eine Reihe v...

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“…Although these techniques are able to visualize ligand-receptor binding events with high spatial resolution, and bring insights into binding properties like binding affinity and kinetics, none of them provide molecular structural information at ligand-receptor binding sites, which is a key factor in mediating binding properties. Chemical elucidation of ligand-receptor binding sites is typically obtained by characterizing crystal structures of purified receptors using x-ray diffraction (XRD) and nuclear magnetic resonance (NMR), and building computational models for analysis [20,21] . New technologies are needed to provide molecular insight into ligand-receptor binding chemistry in cell membranes, where the cellular environment can impact receptor-ligand interactions.…”

Section: Hhs Public Accessmentioning

confidence: 99%

Targeted-TERS detection of integrin receptors on human cancer cells

Xiao

Schultz

2016

Cancer Cell Microenviron

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Membrane receptors play important roles in regulating cellular activities. Targeting membrane receptors in cancer cells and understanding their interactions with specific ligands are key for cancer prognosis and therapeutics. However, there is a need to develop new technologies to provide molecular insight into ligand-receptor binding chemistry in cell membrane. Integrin receptors are important membrane receptors that regulate cellular migration, invasion and proliferation in tumors. Integrins have a well-known affinity towards small peptide ligands containing arginine-glycine-aspartate (RGD) sequence and are therefore an attractive model system to study ligand-receptor interactions. We have recently reported a method to detect integrin receptors and study their binding chemistry with cyclic-RGDfC ligand using tip-enhanced Raman scattering (TERS). We have demonstrated that two integrins with similar structures can be differentiated in intact cell membrane, due to the differences in their RGD ligand binding sites, showing the potential of this TERS methodology to study other membrane receptors and their interactions in live cells. KeywordsTip-enhanced Raman scattering; integrin; ligand-receptor binding; binding chemistry While cellular membrane receptors are key molecules that initiate signaling pathways to regulate cellular activities and have been strongly associated with cancer progression, the tools available to identify relevant chemical reactions are limited. Recently we demonstrated that tip enhanced Raman scattering (TERS) may provide new insights into understanding the chemical interactions between specific extracellular molecules (so-called "ligands").Many overexpressed membrane receptors have been identified as hallmarks of various types of tumors, leading to diagnosis and treatment strategies that target these receptors [1,2] . One widely studied example is integrin receptors. These receptors are important cell adhesion receptors that act as bridge molecules for cell-cell and cell-extracellular matrix (ECM) * Corresponding Author's Schultz.41@nd.edu, Fax: (574) 631-6652. Author Contributions L.X. and Z.D.S. wrote the manuscript. Conflicting interestsThe authors have declared that no competing interests exist. [3] . Because of these biological roles in tumors, integrins have been recognized as molecular markers for targeted cancer imaging [4,5] . For example, arginine-glycine-aspartate (RGD) peptide conjugated magnetic nanoparticles were found to provide significantly enhanced MRI image contrast at tumor areas, mediated through RGD-integrin interaction, in a xenograft model [6] . In addition, integrins have been targeted for drug developments in therapeutics of human cancers. Preclinical studies have shown that integrin antagonists, including monoclonal antibodies and RGD peptides, can inhibit tumor growth [7,8] . For example, Cilengitide, a cyclic-RGD based drug molecule, which is a highly potent antagonist of integrins αvβ3, αvβ5 and α5β1, reached clinical phase III trials for treatments of ...

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Ligand Binding Analysis for Human α5β1 Integrin: Strategies for Designing New α5β1 Integrin Antagonists

Cited by 75 publications

References 34 publications

The Small α5β1 Integrin Antagonist, SJ749, Reduces Proliferation and Clonogenicity of Human Astrocytoma Cells

The Small α5β1 Integrin Antagonist, SJ749, Reduces Proliferation and Clonogenicity of Human Astrocytoma Cells

Rationales Design von hoch aktiven und selektiven Liganden für α5β1‐ und αvβ3‐Integrine

Targeted-TERS detection of integrin receptors on human cancer cells

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