scholarly journals Exploring the signaling space of a GPCR using bivalent ligands with a rigid oligoproline backbone

2021 ◽  
Vol 118 (48) ◽  
pp. e2108776118
Author(s):  
Nina Romantini ◽  
Shahidul Alam ◽  
Stefanie Dobitz ◽  
Martin Spillmann ◽  
Martina De Foresta ◽  
...  
Keyword(s):  
Drug Target ◽  
G Protein Coupled Receptors ◽  
Bivalent Ligands ◽  
Dimer Formation ◽  
Peptide Receptor ◽  
Gastrin Releasing Peptide ◽  
Fixed Distance ◽  
Recognition Motifs ◽  
G Protein Coupled ◽  
Important Drug

G protein–coupled receptors (GPCRs) are one of the most important drug–target classes in pharmaceutical industry. Their diversity in signaling, which can be modulated with drugs, permits the design of more effective and better-tolerated therapeutics. In this work, we have used rigid oligoproline backbones to generate bivalent ligands for the gastrin-releasing peptide receptor (GRPR) with a fixed distance between their recognition motifs. This allows the stabilization of GPCR dimers irrespective of their physiological occurrence and relevance, thus expanding the space for medicinal chemistry. Specifically, we observed that compounds presenting agonists or antagonists at 20- and 30-Å distance induce GRPR dimerization. Furthermore, we found that 1) compounds with two agonists at 20- and 30-Å distance that induce dimer formation show bias toward Gq efficacy, 2) dimers with 20- and 30-Å distance have different potencies toward β-arrestin-1 and β-arrestin-2, and 3) the divalent agonistic ligand with 10-Å distance specifically reduces Gq potency without affecting β-arrestin recruitment, pointing toward an allosteric effect. In summary, we show that rigid oligoproline backbones represent a tool to develop ligands with biased GPCR signaling.

scholarly journals The potential of different Autotaxin inhibitor types regulating catalysis-dependent and -independent signalling

2019 ◽  
Author(s):  
Fernando Salgado Polo ◽  
Anastassis Perrakis
Keyword(s):  
Drug Target ◽  
Cellular Responses ◽  
Binding Mode ◽  
G Protein Coupled Receptors ◽  
Allosteric Site ◽  
Physiological Processes ◽  
Independent Functions ◽  
G Protein Coupled ◽  
Mediated Catalysis ◽  
Important Drug

Autotaxin (ATX) is a secreted lysophospholipase D, catalysing the conversion of lysophosphatidylcholine (LPC) to bioactive lysophosphatidic acid (LPA). LPA acts through two families of G protein-coupled receptors (GPCRs) controlling key cellular responses, and is implicated in many physiological processes and pathologies. ATX has therefore been established as an important drug target in the pharmaceutical industry. Structural and biochemical studies of ATX have shown that it has a bimetallic nucleophilic catalytic site, a substrate-binding (orthosteric) hydrophobic pocket that accommodates the lipid alkyl chain, and an allosteric tunnel that can accommodate various steroids and LPA. Here we first review what is known about ATX-mediated catalysis, crucially in light of allosteric regulation. We then present the known ATX catalysis-independent functions, including binding to cell-surface integrins and proteoglycans. In light of these data we then discuss the four types of ATX inhibitors, as classified depending on their binding to the orthosteric and/or the allosteric site. Finally, we analyse the binding mode of known members of all four types and discuss how mechanistic differences might differentially modulate the activity of the ATX-LPA signalling axis, and clinical applications including cancer.

scholarly journals The Structural Binding Mode of the Four Autotaxin Inhibitor Types that Differentially Affect Catalytic and Non-Catalytic Functions

Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1577 ◽  
Author(s):  
Fernando Salgado-Polo ◽  
Anastassis Perrakis
Keyword(s):  
Drug Target ◽  
Binding Mode ◽  
G Protein Coupled Receptors ◽  
Allosteric Site ◽  
Physiological Processes ◽  
Independent Functions ◽  
Catalytic Functions ◽  
G Protein Coupled ◽  
Mediated Catalysis ◽  
Important Drug

Autotaxin (ATX) is a secreted lysophospholipase D, catalysing the conversion of lysophosphatidylcholine (LPC) to bioactive lysophosphatidic acid (LPA). LPA acts through two families of G protein-coupled receptors (GPCRs) controlling key cellular responses, and it is implicated in many physiological processes and pathologies. ATX, therefore, has been established as an important drug target in the pharmaceutical industry. Structural and biochemical studies of ATX have shown that it has a bimetallic nucleophilic catalytic site, a substrate-binding (orthosteric) hydrophobic pocket that accommodates the lipid alkyl chain, and an allosteric tunnel that can accommodate various steroids and LPA. In this review, first, we revisit what is known about ATX-mediated catalysis, crucially in light of allosteric regulation. Then, we present the known ATX catalysis-independent functions, including binding to cell surface integrins and proteoglycans. Next, we analyse all crystal structures of ATX bound to inhibitors and present them based on the four inhibitor types that are established based on the binding to the orthosteric and/or the allosteric site. Finally, in light of these data we discuss how mechanistic differences might differentially modulate the activity of the ATX-LPA signalling axis, and clinical applications including cancer.

Current Status in the Design and Development of Agonists and Antagonists of Adenosine A3 Receptor as Potential Therapeutic Agents

2019 ◽  
Vol 25 (25) ◽  
pp. 2772-2787 ◽  
Author(s):  
Raghu P. Mailavaram ◽  
Omar H.A. Al-Attraqchi ◽  
Supratik Kar ◽  
Shinjita Ghosh
Keyword(s):  
Drug Target ◽  
Therapeutic Agents ◽  
G Protein Coupled Receptors ◽  
Current Status ◽  
Renal Diseases ◽  
Adenosine A3 Receptor ◽  
Drug Candidates ◽  
Novel Drugs ◽  
The Family ◽  
G Protein Coupled

Adenosine receptors (ARs) belongs to the family of G-protein coupled receptors (GPCR) that are responsible for the modulation of a wide variety of physiological functions. The ARs are also implicated in many diseases such as cancer, arthritis, cardiovascular and renal diseases. The adenosine A3 receptor (A3AR) has emerged as a potential drug target for the progress of new and effective therapeutic agents for the treatment of various pathological conditions. This receptor’s involvement in many diseases and its validity as a target has been established by many studies. Both agonists and antagonists of A3AR have been extensively investigated in the last decade with the goal of developing novel drugs for treating diseases related to immune disorders, inflammation, cancer, and others. In this review, we shall focus on the medicinal chemistry of A3AR ligands, exploring the diverse chemical classes that have been projected as future leading drug candidates. Also, the recent advances in the therapeuetic applications of A3AR ligands are highlighted.

scholarly journals In Vivo Biodistribution and Efficacy Evaluation of NeoB, a Radiotracer Targeted to GRPR, in Mice Bearing Gastrointestinal Stromal Tumor

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1051
Author(s):  
Christopher Montemagno ◽  
Florian Raes ◽  
Mitra Ahmadi ◽  
Sandrine Bacot ◽  
Marlène Debiossat ◽  
...  
Keyword(s):  
Therapeutic Agent ◽  
Tumor Volume ◽  
Tumor Regression ◽  
Efficacy Evaluation ◽  
Peptide Receptor ◽  
Gastrin Releasing Peptide ◽  
Target Organs ◽  
G Protein Coupled ◽  
Complete Tumor

NeoB is a radiotracer targeting the gastrin-releasing peptide receptor (GRPR), a G-protein–coupled receptor expressed in various cancers. The aim of the present study was to evaluate the biodistribution and efficacy of this new therapeutic agent in Gastrointestinal Stromal Tumors (GIST). Eighty-two SCID mice bearing GIST-882 tumors were employed. [177Lu]Lu-NeoB biodistribution was evaluated up to seven days by organ sampling (200 pmol/0.8 MBq, i.v.). For efficacy evaluation, mice received either saline, 400 pmol or 800 pmol of [177Lu]Lu-NeoB (37MBq, 1/w, 3 w, i.v.). SPECT/CT imaging was performed at 24 h, and tumor volume was determined up to 100 days. Elevated and specific [177Lu]Lu-NeoB uptake was found in the GIST tumor, as demonstrated by in vivo competition (19.1 ± 3.9 %ID/g vs. 0.3 ± 0.1 %ID/g at 4h). [177Lu]Lu-NeoB tumor retention (half-life of 40.2 h) resulted in elevated tumor-to-background ratios. Tumor volumes were significantly reduced in both treated groups (p < 0.01), even leading to complete tumor regression at the 400 pmol dose. [177Lu]Lu-NeoB exhibited excellent pharmacokinetics with elevated and prolonged tumor uptake and low uptake in non-target organs such as pancreas. The potential of this new theragnostic agent in different indications, including GIST, is under evaluation in the FIH [177Lu]Lu-NeoB clinical trial.

Drug-Target Residence Time-A Case for G Protein-Coupled Receptors

2014 ◽  
Vol 34 (4) ◽  
pp. 856-892 ◽  
Author(s):  
Dong Guo ◽  
Julia M. Hillger ◽  
Adriaan P. IJzerman ◽  
Laura H. Heitman
Keyword(s):  
G Protein ◽  
Residence Time ◽  
Drug Target ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled

scholarly journals The tyrosine phosphatase CD148 is an essential positive regulator of platelet activation and thrombosis

Blood ◽  
2009 ◽  
Vol 113 (20) ◽  
pp. 4942-4954 ◽  
Author(s):  
Yotis A. Senis ◽  
Michael G. Tomlinson ◽  
Stuart Ellison ◽  
Alexandra Mazharian ◽  
Jenson Lim ◽  
...  
Keyword(s):  
G Protein ◽  
Platelet Activation ◽  
Drug Target ◽  
Tyrosine Phosphatase ◽  
Underlying Mechanism ◽  
G Protein Coupled Receptors ◽  
Bleeding Tendency ◽  
Platelet Surface ◽  
Surface Receptors ◽  
G Protein Coupled

Abstract Platelets play a fundamental role in hemostasis and thrombosis. They are also involved in pathologic conditions resulting from blocked blood vessels, including myocardial infarction and ischemic stroke. Platelet adhesion, activation, and aggregation at sites of vascular injury are regulated by a diverse repertoire of tyrosine kinase–linked and G protein–coupled receptors. Src family kinases (SFKs) play a central role in initiating and propagating signaling from several platelet surface receptors; however, the underlying mechanism of how SFK activity is regulated in platelets remains unclear. CD148 is the only receptor-like protein tyrosine phosphatase identified in platelets to date. In the present study, we show that mutant mice lacking CD148 exhibited a bleeding tendency and defective arterial thrombosis. Basal SFK activity was found to be markedly reduced in CD148-deficient platelets, resulting in a global hyporesponsiveness to agonists that signal through SFKs, including collagen and fibrinogen. G protein–coupled receptor responses to thrombin and other agonists were also marginally reduced. These results highlight CD148 as a global regulator of platelet activation and a novel antithrombotic drug target.

Challenges in Design and Development of PAR Inhibitors

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. SCI-45-SCI-45
Author(s):  
Patricia Andrade-Gordon
Keyword(s):  
Drug Target ◽  
Human Platelet ◽  
Bleeding Risk ◽  
G Protein Coupled Receptors ◽  
Protease Activated Receptors ◽  
Small Molecule Antagonist ◽  
Clinical Benefits ◽  
Platelet Aggregates ◽  
G Protein Coupled ◽  
Sustained Activation

Abstract Abstract SCI-45 Inappropriate and sustained activation of platelets is a major cause of vascular occlusive diseases such as angina, myocardial infarction, and stroke. The development of thrombi within blood vessels results from the formation of platelet aggregates and fibrin deposits, and heavily depends on the actions of α-thrombin. It is now well recognized that human platelet responses to α-thrombin are mediated by the protease-activated receptors PAR1 and PAR4. Protease-activated receptors (PARs) represent a unique family of seven-transmembrane G-protein-coupled receptors, which are enzymatically cleaved to expose a new extracellular N-terminus that acts as a “tethered” activating ligand. Since the discovery of PAR1 as the major contributor to human platelet aggregation, there has been a keen interest to develop antagonist as potential antithrombotics. However, there have been many issues and challenges in this endeavor. One crucial challenge to the discovery of potent antagonists is the strong entropy advantage offered by the intramolecular binding mechanism of PARs activation, which presents a great disadvantage to a circulating small molecule antagonist. To be an effective therapeutic agent, a PAR1 antagonist not only should bind tightly to the receptor but also possess suitable binding kinetics. Another issue for the discovery of PAR1 antagonists is the preclinical logistics associated with species variability of PAR1 on platelets. Despite these challenges, PAR1 has been an attractive drug target and there has been considerable activity and progress in the discovery and development of PAR1 antagonist as therapeutic agents. The promise of these novel therapeutics is reflected by two antiplatelet PAR1 antagonists in advanced clinical trials. The clinical benefits derived from these agents will be determined by the tight balance between delivering efficacy in the context of thrombotic disease and controlling the bleeding risk. The discussion will focus on the challenges from discovery to development of these great potential opportunities in the prevention of atherothrombotic disease. Disclosures: Andrade-Gordon: Johnson & Johnson: Employment.

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