Mariangela Urbano

Sphingosine 1-phosphate receptor agonists: a patent review (2010 – 2012)

Introduction: The sphingosine-1-phosphate (S1P)-driven signaling regulates fundamental biological functions, including cell proliferation, angiogenesis, endothelial cell chemotaxis, immune cell trafficking and mitogenesis. A large body of research has been focusing on the development of immunosuppressive S1P1 receptor (S1P1-R) agonist molecules. The S1P1,3 – 5-R pan-agonist fingolimod (FTY720) has been approved by the FDA for the treatment of relapsing–remitting multiple sclerosis. However, FTY720 is now contraindicated in patients with compromised cardiac function. Although the main adverse effect bradycardia has been linked to the S1P3-R activation, cardiovascular liabilities persist with more selective S1P1-R agonists that have entered clinical trials. In contrast to the S1P1-R, the therapeutic application of the S1P2 – 5-Rs remains poorly explored. Areas covered: This review provides the patent literature from 2010 to date on S1P-R agonist molecules and their relevant biological properties. Expert opinion: Limited progress has been made on agonists at S1P4,5-R subtypes, with some families of S1P5-R agonists showing promising results in animal models of age-related cognitive disorders. A discrete number of reviewed molecules are S1P1-R agonists with a promising clinical outlook in transplantation, inflammation, cancer and autoimmune settings. Further preclinical and clinical studies will determine whether the new developed S1P1-R agonists do indeed improve the safety profile of FTY720.

Modulators of the Sphingosine 1-phosphate receptor 1.

The Sphingosine 1-phosphate receptor (S1P-R) signaling system has proven to be of biological and medical importance in autoimmune settings. S1P1-R is a validated drug target for multiple sclerosis (MS) for which FTY720 (Fingolimod), a S1P1,3-5-R pan-agonist, was recently approved as the first orally active drug for the treatment of relapsing-remitting MS. Transient bradycardia and long half-life are the FTY720 critical pitfalls. This review provides the latest advances on next-generation S1P1-R modulators from 2012 up to date, with an overview of the chemical structures, structure-activity relationships, and relevant biological and clinical properties.

Antagonists of the kappa opioid receptor.

The research community has increasingly focused on the development of OPRK antagonists as pharmacotherapies for the treatment of depression, anxiety, addictive disorders and other psychiatric conditions produced or exacerbated by stress. Short-acting OPRK antagonists have been recently developed as a potential improvement over long-acting prototypic ligands including nor-BNI and JDTic. Remarkably the short-acting LY2456302 is undergoing phase II clinical trials for the augmentation of the antidepressant therapy in treatment-resistant depression. This Letter reviews relevant chemical and pharmacological advances in the identification and development of OPRK antagonists.

Discovery, Design and Synthesis of the First Reported Potent and Selective Sphingosine-1-Phosphate 4 (S1P4) Receptor Antagonists

Selective S1P(4) receptor antagonists could be novel therapeutic agents for the treatment of influenza infection in addition to serving as a useful tool for understanding S1P(4) receptor biological functions. 5-(2,5-Dichlorophenyl)-N-(2,6-dimethylphenyl)furan-2-carboxamide was identified from screening the Molecular Libraries-Small Molecule Repository (MLSMR) collection and selected as a promising S1P(4) antagonist hit with moderate in vitro potency and high selectivity against the other family receptor subtypes (S1P(1-3,5)). Rational chemical modifications of the hit allowed the disclosure of the first reported highly selective S1P(4) antagonists with low nanomolar activity and adequate physicochemical properties suitable for further lead-optimization studies.

SAR Analysis of Innovative Selective Small Molecule Antagonists of Sphingosine-1-Phosphate 4 (S1P4) Receptor

Recent evidence suggests an innovative application of chemical modulators targeting the S1P(4) receptor as novel mechanism-based drugs for the treatment of influenza virus infection. Modulation of the S1P(4) receptor may also represent an alternative therapeutic approach for clinical conditions where reactive thrombocytosis is an undesired effect or increased megakaryopoiesis is required. With the exception of our recent research program disclosure, we are not aware of any selective S1P(4) antagonists reported in the literature to date. Herein, we describe complementary structure-activity relationships (SAR) of the high-throughput screening (HTS)-derived hit 5-(2,5-dichlorophenyl)-N-(2,6-dimethylphenyl)furan-2-carboxamide and its 2,5-dimethylphenyl analog. Systematic structural modifications of the furan ring showed that both steric and electronic factors in this region have a significant impact on the potency. The furan moiety was successfully replaced with a thiophene or phenyl ring maintaining potency in the low nanomolar range and high selectivity against the other S1P receptor subtypes. By expanding the molecular diversity within the hit-derived class, our SAR study provides innovative small molecule potent and selective S1P(4) antagonists suitable for in vivo pharmacological validation of the target receptor.

Discovery, synthesis and SAR analysis of novel selective small molecule S1P4-R agonists based on a (2Z,5Z)-5-((pyrrol-3-yl)methylene)-3-alkyl-2-(alkylimino)thiazolidin-4-one chemotype

High affinity and selective S1P(4) receptor (S1P(4)-R) small molecule agonists may be important proof-of-principle tools used to clarify the receptor biological function and effects to assess the therapeutic potential of the S1P(4)-R in diverse disease areas including treatment of viral infections and thrombocytopenia. A high-throughput screening campaign of the Molecular Libraries-Small Molecule Repository was carried out by our laboratories and identified (2Z,5Z)-5-((1-(2-fluorophenyl)-2,5-dimethyl-1H-pyrrol-3-yl)methylene)-3-methyl-2-(methylimino) thiazolidin-4-one as a promising S1P(4)-R agonist hit distinct from literature S1P(4)-R modulators. Rational chemical modifications of the hit allowed the identification of a promising lead molecule with low nanomolar S1P(4)-R agonist activity and exquisite selectivity over the other S1P(1-3,5)-Rs family members. The lead molecule herein disclosed constitutes a valuable pharmacological tool to explore the effects of the S1P(4)-R signaling cascade and elucidate the molecular basis of the receptor function.

Discovery, Design and Synthesis of Novel Potent and Selective Sphingosine-1-Phosphate 4 Receptor (S1P4-R) Agonists

High affinity and selective small molecule agonists of the S1P(4) receptor (S1P(4)-R) may have significant therapeutic utility in diverse disease areas including autoimmune diseases, viral infections and thrombocytopenia. A high-throughput screening (HTS) of the Molecular Libraries-Small Molecule Repository library identified 3-(2-(2,4-dichlorophenoxy)ethoxy)-6-methyl-2-nitropyridine as a moderately potent and selective S1P(4)-R hit agonist. Design, synthesis and systematic structure-activity relationships study of the HTS-derived hit led to the development of novel potent S1P(4)-R agonists exquisitely selective over the remaining S1P(1-3,5)-Rs family members. Remarkably, the molecules herein reported provide novel pharmacological tools to decipher the biological function and assess the therapeutic utility of the S1P(4)-R.

Sphingosine 1-phosphate receptor 1 agonists: a patent review (2013-2015)

ABSTRACT Introduction: The sphingosine-1-phosphate (S1P) regulates diverse biological functions including cell proliferation, endothelial cell chemotaxis, angiogenesis, immune cell trafficking, mitogenesis, heart rate. The first-in-class S1P1,3–5-R pan-agonist fingolimod (FTY720) was approved by the FDA and EMEA for the treatment of relapsing-remitting multiple sclerosis, though the most common adverse effect is bradycardia which occurs in the early stage of treatment and resolves within the first 24 h despite continuing treatment. The underlying mechanism of the cardiovascular effects is the activation of G-protein-gated inwardly rectifying potassium (GIRK) channel by the S1P1-R. Several second generation S1P1-R agonists with distinct selectivity, pharmacokinetics and safety profile from FTY720 are under development for the treatment of autoimmune and chronic inflammatory diseases. Areas covered: This review provides a summary of the patent literature from 2013 up to November 2015 on the S1P1-R agonist molecules and their relevant biological/pharmacological properties. Expert opinion: The molecules reviewed are S1P1-R agonists with a promising clinical outlook in particular in inflammation and autoimmune diseases. Clinical and preclinical studies of second generation S1P1-R agonists have been generating interesting results and may finally provide pharmacological agents with improved therapeutic profile than FTY720, particularly in terms of cardiovascular and pulmonary liabilities.

Discovery, design and synthesis of a selective S1P3 receptor allosteric agonist

Potent and selective S1P3 receptor (S1P3-R) agonists may represent important proof-of-principle tools used to clarify the receptor biological function and assess the therapeutic potential of the S1P3-R in cardiovascular, inflammatory and pulmonary diseases. N,N-Dicyclohexyl-5-propylisoxazole-3-carboxamide was identified by a high-throughput screening of MLSMR library as a promising S1P3-R agonist. Rational chemical modifications of the hit allowed the identification of N,N-dicyclohexyl-5-cyclopropylisoxazole-3-carboxamide, a S1P3-R agonist endowed with submicromolar activity and exquisite selectivity over the remaining S1P1,2,4,5-R family members. A combination of ligand competition, site-directed mutagenesis and molecular modeling studies showed that the N,N-dicyclohexyl-5-cyclopropylisoxazole-3-carboxamide is an allosteric agonist and binds to the S1P3-R in a manner that does not disrupt the S1P3-R-S1P binding. The lead molecule herein disclosed constitutes a valuable pharmacological tool to explore the molecular basis of the receptor function, and provides the bases for further rational design of more potent and drug-like S1P3-R allosteric agonists.

SAR analysis of novel non-peptidic NPBWR1 (GPR7) antagonists.

In this Letter we report on the advances in our NPBWR1 antagonist program aimed at optimizing the 5-chloro-2-(3,5-dimethylphenyl)-4-(4-methoxyphenoxy)pyridazin-3(2H)-one lead molecule previously obtained from a high-throughput screening (HTS)-derived hit. Synthesis and structure-activity relationships (SAR) studies around the 3,5-dimethylphenyl and 4-methoxyphenyl regions resulted in the identification of a novel series of non-peptidic submicromolar NPBWR1 antagonists based on a 5-chloro-4-(4-alkoxyphenoxy)-2-(benzyl)pyridazin-3(2H)-one chemotype. Amongst them, 5-chloro-2-(9H-fluoren-9-yl)-4-(4-methoxyphenoxy)pyridazin-3(2H)-one 9h (CYM50769) inhibited NPW activation of NPBWR1 with a submicromolar IC(50), and displayed high selectivity against a broad array of off-targets with pharmaceutical relevance. Our medicinal chemistry study provides innovative non-peptidic selective NPBWR1 antagonists that may enable to clarify the biological role and therapeutic utility of the target receptor in the regulation of feeding behavior, pain, stress, and neuroendocrine function.