2-(Fluoromethoxy)-4'-(S-methanesulfonimidoyl)-1,1'-biphenyl (UCM-1306), an Orally Bioavailable Positive Allosteric Modulator of the Human Dopamine D1 Receptor for Parkinson's Disease

Tolerance development caused by dopamine replacement with l-DOPA and therapeutic drawbacks upon activation of dopaminergic receptors with orthosteric agonists reveal a significant unmet need for safe and effective treatment of Parkinson’s disease. In search for selective modulators of the D₁ receptor, the screening of a chemical library and subsequent medicinal chemistry program around an identified hit resulted in new synthetic compound 26 [UCM-1306, 2-(fluoromethoxy)-4′-(S-methanesulfonimidoyl)-1,1′-biphenyl] that increases the dopamine maximal effect in a dose-dependent manner in human and mouse D₁ receptors, is inactive in the absence of dopamine, modulates dopamine affinity for the receptor, exhibits subtype selectivity, and displays low binding competition with orthosteric ligands. The new allosteric modulator potentiates cocaine-induced locomotion and enhances l-DOPA recovery of decreased locomotor activity in reserpinized mice after oral administration. The behavior of compound 26 supports the interest of a positive allosteric modulator of the D₁ receptor as a promising therapeutic approach for Parkinson’s disease.

Novel Antagonist of the Type 2 Lysophosphatidic Acid Receptor (LPA2), UCM-14216, Ameliorates Spinal Cord Injury in Mice

Spinal cord injuries (SCIs) irreversibly disrupt spinal connectivity, leading to permanent neurological disabilities. Current medical treatments for reducing the secondary damage that follows the initial injury are limited to surgical decompression and anti-inflammatory drugs, so there is a pressing need for new therapeutic strategies. Inhibition of the type 2 lysophosphatidic acid receptor (LPA₂) has recently emerged as a new potential pharmacological approach to decrease SCI-associated damage. Toward validating this receptor as a target in SCI, we have developed a new series of LPA₂ antagonists, among which compound 54 (UCM-14216) stands out as a potent and selective LPA₂ receptor antagonist (E_max = 90%, IC₅₀ = 1.9 μM, K_D = 1.3 nM; inactive at LPA_1,3–6 receptors). This compound shows efficacy in an in vivo mouse model of SCI in an LPA₂-dependent manner, confirming the potential of LPA₂ inhibition for providing a new alternative for treating SCI.

Isoprenylcysteine Carboxylmethyltransferase-Based Therapy for Hutchinson-Gilford Progeria Syndrome

Hutchinson-Gilford progeria syndrome (HGPS, progeria) is a rare genetic disease characterized by premature aging and death in childhood for which there were no approved drugs for its treatment until last November, when lonafarnib obtained long-sought FDA approval. However, the benefits of lonafarnib in patients are limited, highlighting the need for new therapeutic strategies. Here, we validate the enzyme isoprenylcysteine carboxylmethyltransferase (ICMT) as a new therapeutic target for progeria with the development of a new series of potent inhibitors of this enzyme that exhibit an excellent antiprogeroid profile. Among them, compound UCM-13207 significantly improved the main hallmarks of progeria. Specifically, treatment of fibroblasts from progeroid mice with UCM-13207 delocalized progerin from the nuclear membrane, diminished its total protein levels, resulting in decreased DNA damage, and increased cellular viability. Importantly, these effects were also observed in patient-derived cells. Using the Lmna ^G609G/G609G progeroid mouse model, UCM-13207 showed an excellent in vivo efficacy by increasing body weight, enhancing grip strength, extending lifespan by 20%, and decreasing tissue senescence in multiple organs. Furthermore, UCM-13207 treatment led to an improvement of key cardiovascular hallmarks such as reduced progerin levels in aortic and endocardial tissue and increased number of vascular smooth muscle cells (VSMCs). The beneficial effects go well beyond the effects induced by other therapeutic strategies previously reported in the field, thus supporting the use of UCM-13207 as a new treatment for progeria.

Targeting the FtsZ Allosteric Binding Site with a Novel Fluorescence Polarization Screen, Cytological and Structural Approaches for Antibacterial Discovery

Bacterial resistance to antibiotics makes previously manageable infections again disabling and lethal, highlighting the need for new antibacterial strategies. In this regard, inhibition of the bacterial division process by targeting key protein FtsZ has been recognized as an attractive approach for discovering new antibiotics. Binding of small molecules to the cleft between the N-terminal guanosine triphosphate (GTP)-binding and the C-terminal subdomains allosterically impairs the FtsZ function, eventually inhibiting bacterial division. Nonetheless, the lack of appropriate chemical tools to develop a binding screen against this site has hampered the discovery of FtsZ antibacterial inhibitors. Herein, we describe the first competitive binding assay to identify FtsZ allosteric ligands interacting with the interdomain cleft, based on the use of specific high-affinity fluorescent probes. This novel assay, together with phenotypic profiling and X-ray crystallographic insights, enables the identification and characterization of FtsZ inhibitors of bacterial division aiming at the discovery of more effective antibacterials.

A Novel Agonist of the Type 1 Lysophosphatidic Acid Receptor (LPA1), UCM-05194, Shows Efficacy in Neuropathic Pain Amelioration

Neuropathic pain (NP) is a complex chronic pain state with a prevalence of almost 10% in the general population. Pharmacological options for NP are limited and weakly effective, so there is a need to develop more efficacious NP attenuating drugs. Activation of the type 1 lysophosphatidic acid (LPA₁) receptor is a crucial factor in the initiation of NP. Hence, it is conceivable that a functional antagonism strategy could lead to NP mitigation. Here we describe a new series of LPA₁ agonists among which derivative (S)-17 (UCM-05194) stands out as the most potent and selective LPA₁ receptor agonist described so far (E_max = 118%, EC₅₀ = 0.24 μM, K_D = 19.6 nM; inactive at autotaxin and LPA_2-6 receptors). This compound induces characteristic LPA₁-mediated cellular effects and prompts the internalization of the receptor leading to its functional inactivation in primary sensory neurons and to an efficacious attenuation of the pain perception in an in vivo model of NP.

A Potent Isoprenylcysteine Carboxylmethyltransferase (ICMT) Inhibitor Improves Survival in Ras-Driven Acute Myeloid Leukemia

Blockade of Ras activity by inhibiting its post-translational methylation catalyzed by isoprenylcysteine carboxylmethyltransferase (ICMT) has been suggested as a promising antitumor strategy. However, the paucity of inhibitors has precluded the clinical validation of this approach. In this work we report a potent ICMT inhibitor, compound 3 [UCM-1336, IC₅₀ = 2 μM], which is selective against the other enzymes involved in the post-translational modifications of Ras. Compound 3 significantly impairs the membrane association of the four Ras isoforms, leading to a decrease of Ras activity and to inhibition of Ras downstream signaling pathways. In addition, it induces cell death in a variety of Ras-mutated tumor cell lines and increases survival in an in vivo model of acute myeloid leukemia. Because ICMT inhibition impairs the activity of the four Ras isoforms regardless of its activating mutation, compound 3 surmounts many of the common limitations of available Ras inhibitors described so far. In addition, these results validate ICMT as a valuable target for the treatment of Ras-driven tumors.

Monoacylglycerol lipase (MAGL) as a promising therapeutic target

Monoacylglycerol lipase (MAGL) has been characterized as the main enzyme responsible for the inactivation of the most abundant brain endocannabinoid, 2-arachidonoylglycerol (2-AG). Besides this role, MAGL has progressively acquired a growing importance as an integrative metabolic hub that controls not only the in vivo levels of 2-AG but also of other monoacylglycerides and, indirectly, the levels of free fatty acids derived from their hydrolysis as well as other lipids with pro-inflammatory or pro-tumorigenic effects, coming from the further metabolism of fatty acids. All these functions have only started to be elucidated in the last years due to the progress made in the knowledge of the structure of MAGL and in the development of genetic and chemical tools. In this review we report the advances made in the field with a special focus on the last decade and how MAGL has become a promising therapeutic target for the treatment of several diseases that currently lack appropriate therapies.

Development of a Fluorescent Bodipy Probe for Visualization of the Serotonin 5-HT1A Receptor in Native Cells of the Immune System

Serotonin (5-HT) modulates key aspects of the immune system. However, its precise function and the receptors involved in the observed effects have remained elusive. Among the different serotonin receptors, 5-HT_1A plays an important role in the immune system given its presence in cells involved in both the innate and adaptive immune responses, but its actual levels of expression under different conditions have not been comprehensively studied due to the lack of suitable tools. To further clarify the role of 5-HT_1A receptor in the immune system, we have developed a fluorescent small molecule probe that enables the direct study of the receptor levels in native cells. This probe allows direct profiling of the receptor expression in immune cells using flow cytometry. Our results show that important subsets of immune cells including human monocytes and dendritic cells express functional 5-HT_1A and that its activation is associated with anti-inflammatory signaling. Furthermore, application of the probe to the experimental autoimmune encephalomyelitis model of multiple sclerosis demonstrates its potential to detect the specific overexpression of the 5-HT_1A receptor in CD4+ T cells. Accordingly, the probe reported herein represents a useful tool whose use can be extended to study the levels of 5-HT_1A receptor in ex vivo samples of different immune system conditions.

2-AG limits Theiler's virus induced acute neuroinflammation by modulating microglia and promoting MDSCs

The innate immune response is mediated by primary immune modulators such as cytokines and chemokines that together with immune cells and resident glia orchestrate CNS immunity and inflammation. Growing evidence supports that the endocannabinoid 2-arachidonoylglycerol (2-AG) exerts protective actions in CNS injury models. Here, we used the acute phase of Theiler's virus induced demyelination disease (TMEV-IDD) as a model of acute neuroinflammation to investigate whether 2-AG modifies the brain innate immune responses to TMEV and CNS leukocyte trafficking. 2-AG or the inhibition of its hydrolysis diminished the reactivity and number of microglia at the TMEV injection site reducing their morphological complexity and modulating them towards an anti-inflammatory state via CB2 receptors. Indeed, 2-AG dampened the infiltration of immune cells into the CNS and inhibited their egress from the spleen, resulting in long-term beneficial effects at the chronic phase of the disease. Intriguingly, it is not a generalized action over leukocytes since 2-AG increased the presence and suppressive potency of myeloid derived suppressor cells (MDSCs) in the brain resulting in higher apoptotic CD4⁺ T cells at the injection site. Together, these data suggest a robust modulatory effect in the peripheral and central immunity by 2-AG and highlight the interest of modulating endogenous cannabinoids to regulate CNS inflammatory conditions.

Blocking Ras inhibition as an antitumor strategy

Ras proteins are among the most frequently mutated drivers in human cancer and remain an elusive pharmaceutical targeting. Previous studies have improved the understanding of Ras structure, processing, and signaling pathways in cancer cells and have opened new possibilities for inhibiting Ras function. In this review we discuss the most recent advances towards inhibiting Ras activity with small molecules, highlighting the two approaches: (i) compounds that bind directly to Ras protein and (ii) inhibitors of the enzymes involved in the post-translational modifications of Ras. In the former, we analyze the most recent contributions in each of the main classes of Ras direct binders, including the different types of nucleotide exchange inhibitors, allosteric compounds, and molecules that interfere with the interaction between Ras and its effectors. In the latter, we examine the compounds that inhibit Ras activation by blocking any of its post-translational modifications. Also, a special focus is made on those molecules that have progressed the farthest from medicinal chemistry and drug development points of view. Finally, the current scene regarding the clinical trials of Ras inhibitors, together with the future promising avenues for further development of the challenging Ras field are reviewed.

A Positive Allosteric Modulator of the Serotonin 5-HT2C Receptor for Obesity

The 5-HT_2CR agonist lorcaserin, clinically approved for the treatment of obesity, causes important side effects mainly related to subtype selectivity. In the search for 5-HT_2CR allosteric modulators as safer antiobesity drugs, a chemical library from Vivia Biotech was screened using ExviTech platform. Structural modifications of identified hit VA240 in synthesized analogues 6-41 afforded compound 11 (N-[(1-benzyl-1H-indol-3-yl)methyl]pyridin-3-amine, VA012), which exhibited dose-dependent enhancement of serotonin efficacy, no significant off-target activities, and low binding competition with serotonin or other orthosteric ligands. PAM 11 was very active in feeding inhibition in rodents, an effect that was not related to the activation of 5-HT_2AR. A combination of 11 with the SSRI sertraline increased the anorectic effect. Subchronic administration of 11 reduced food intake and body weight gain without causing CNS-related malaise. The behavior of compound 11 identified in this work supports the interest of a serotonin 5-HT_2CR PAM as a promising therapeutic approach for obesity.

The structural assembly switch of cell division protein FtsZ probed with fluorescent allosteric inhibitors

FtsZ is a widely conserved tubulin-like GTPase that directs bacterial cell division and a new target for antibiotic discovery. This protein assembly machine cooperatively polymerizes forming single-stranded filaments, by means of self-switching between inactive and actively associating monomer conformations. The structural switch mechanism was proposed to involve a movement of the C-terminal and N-terminal FtsZ domains, opening a cleft between them, allosterically coupled to the formation of a tight association interface between consecutive subunits along the filament. The effective antibacterial benzamide PC190723 binds into the open interdomain cleft and stabilizes FtsZ filaments, thus impairing correct formation of the FtsZ ring for cell division. We have designed fluorescent analogs of PC190723 to probe the FtsZ structural assembly switch. Among them, nitrobenzoxadiazole probes specifically bind to assembled FtsZ rather than to monomers. Probes with several spacer lengths between the fluorophore and benzamide moieties suggest a binding site extension along the interdomain cleft. These probes label FtsZ rings of live Bacillus subtilis and Staphylococcus aureus, without apparently modifying normal cell morphology and growth, but at high concentrations they induce impaired bacterial division phenotypes typical of benzamide antibacterials. During the FtsZ assembly-disassembly process, the fluorescence anisotropy of the probes changes upon binding and dissociating from FtsZ, thus reporting open and closed FtsZ interdomain clefts. Our results demonstrate the structural mechanism of the FtsZ assembly switch, and suggest that the probes bind into the open clefts in cellular FtsZ polymers preferably to unassembled FtsZ in the bacterial cytosol.

A new serotonin 5-HT6 receptor antagonist with procognitive activity - Importance of a halogen bond interaction to stabilize the binding

Serotonin 5-HT6 receptor has been proposed as a promising therapeutic target for cognition enhancement though the development of new antagonists is still needed to validate these molecules as a drug class for the treatment of Alzheimer's disease and other pathologies associated with memory deficiency. As part of our efforts to target the 5-HT6 receptor, new benzimidazole-based compounds have been designed and synthesized. Site-directed mutagenesis and homology models show the importance of a halogen bond interaction between a chlorine atom of the new class of 5-HT6 receptor antagonists identified herein and a backbone carbonyl group in transmembrane domain 4. In vitro pharmacological characterization of 5-HT6 receptor antagonist 7 indicates high affinity and selectivity over a panel of receptors including 5-HT2B subtype and hERG channel, which suggests no major cardiac issues. Compound 7 exhibited in vivo procognitive activity (1 mg/kg, ip) in the novel object recognition task as a model of memory deficit.

Development of a Nucleotide Exchange Inhibitor That Impairs Ras Oncogenic Signaling

Despite more than three decades of intense effort, no anti-Ras therapies have reached clinical application. Contributing to this failure has been an underestimation of Ras complexity and a dearth of structural information. In this regard, recent studies have revealed the highly dynamic character of the Ras surface and the existence of transient pockets suitable for small-molecule binding, opening up new possibilities for the development of Ras modulators. Herein, a novel Ras inhibitor (compound 12) is described that selectively impairs mutated Ras activity in a reversible manner without significantly affecting wild-type Ras, reduces the Ras-guanosine triphosphate (GTP) levels, inhibits the activation of the mitogen-activated protein kinase (MAPK) pathway, and exhibits remarkable cytotoxic activity in Ras-driven cellular models. The use of molecular dynamics simulations and NMR spectroscopy experiments has enabled the molecular bases responsible for the interactions between compound 12 and Ras protein to be explored. The new Ras inhibitor binds partially to the GTP-binding region and extends into the adjacent hydrophobic pocket delimited by switch II. Hence, Ras inhibitor 12 could represent a new compound for the development of more efficacious drugs to target Ras-driven cancers; a currently unmet clinical need.

Effective GTP-replacing FtsZ inhibitors and antibacterial mechanism of action

Essential cell division protein FtsZ is considered an attractive target in the search for antibacterials with novel mechanisms of action to overcome the resistance problem. FtsZ undergoes GTP-dependent assembly at midcell to form the Z-ring, a dynamic structure that evolves until final constriction of the cell. Therefore, molecules able to inhibit its activity will eventually disrupt bacterial viability. In this work, we report a new series of small molecules able to replace GTP and to specifically inhibit FtsZ, blocking the bacterial division process. These new synthesized inhibitors interact with the GTP-binding site of FtsZ (Kd = 0.4-0.8 μM), display antibacterial activity against Gram-positive pathogenic bacteria, and show selectivity against tubulin. Biphenyl derivative 28 stands out as a potent FtsZ inhibitor (Kd = 0.5 μM) with high antibacterial activity [MIC (MRSA) = 7 μM]. In-depth analysis of the mechanism of action of compounds 22, 28, 33, and 36 has revealed that they act as effective inhibitors of correct FtsZ assembly, blocking bacterial division and thus leading to filamentous undivided cells. These findings provide a compelling rationale for the development of compounds targeting the GTP-binding site as antibacterial agents and open the door to antibiotics with novel mechanisms of action.

The status of the lysophosphatidic acid receptor type 1 (LPA1R)

The current status of the LPA₁receptor and its ligands in the drug development pipeline is reviewed.

A reversible and selective inhibitor of monoacylglycerol lipase ameliorates multiple sclerosis

Monoacylglycerol lipase (MAGL) is the enzyme responsible for the inactivation of the endocannabinoid 2-arachidonoylglycerol (2-AG). MAGL inhibitors show analgesic and tissue-protecting effects in several disease models. However, the few efficient and selective MAGL inhibitors described to date block the enzyme irreversibly, and this can lead to pharmacological tolerance. Hence, additional classes of MAGL inhibitors are needed to validate this enzyme as a therapeutic target. Here we report a potent, selective, and reversible MAGL inhibitor (IC50=0.18 μM) which is active in vivo and ameliorates the clinical progression of a multiple sclerosis (MS) mouse model without inducing undesirable CB1 -mediated side effects. These results support the interest in MAGL as a target for the treatment of MS.

New serotonin 5-HT1A receptor agonists endowed with antinociceptive activity in vivo

We report the synthesis of new compounds 4-35 based on two different openings (A and B) of the chromane ring present in the previously identified 5-HT1A receptor (5-HT1AR) ligand 3. The synthesized compounds were assessed for binding affinity, selectivity, and functional activity at the 5-HT1AR. Selected candidates resulting from B opening were also evaluated for their potential antinociceptive effect in vivo and pharmacokinetic properties in vitro. Analogue 19 [2-(4-{[2-(2-ethoxyphenoxy)ethyl]amino}butyl)tetrahydro-1H-pyrrolo[1,2-c]imidazole-1,3(2H)-dione] has been characterized as a high-affinity and potent 5-HT1AR agonist (Ki = 2.3 nM; EC50 = 19 nM). Pharmacokinetic studies indicated that compound 19 displays a good metabolic stability in human liver microsomes (t1/2 ∼ 3 h and CLint = 3.5 mL/min/kg, at 5 μM), and a low level of protein binding (25%, at 5 μM). Interestingly, 19 (3 mg/kg, ip, and 30 mg/kg, po) caused significant attenuation of formalin-induced behavior in early and late phases of the mouse intradermal formalin test of pain, and this in vivo effect was reversed by the selective 5-HT1AR antagonist WAY-100635. Thus, the new 5-HT1AR agonist identified in this work, 19, exhibits oral analgesic activity, and the results herein represent a step toward identifying new therapeutics for the control of pain.

Inhibition of Fatty Acid Amidohydrolase, the Enzyme Responsible for the Metabolism of the Endocannabinoid Anandamide, by Analogues of Arachidonoyl-serotonin

Arachidonoyl-serotonin inhibits in a mixed-type manner the metabolism of the endocannabinoid anandamide by the enzyme fatty acid amidohydrolase. In the present study, compounds related to arachidonoyl-serotonin have been synthesised and investigated for their ability to inhibit anandamide hydrolysis by this enzyme in rat brain homogenates. Removal of the 5-hydroxy from the serotonin head group of arachidonoyl-serotonin produced a compound (N-arachidonoyltryptamine) that was a 2.3-fold weaker inhibitor of anandamide hydrolysis, but which also produced its inhibition by a mixed-type manner (Ki(slope) 1.3 microM; Ki(intercept) 44 microM). Replacement of the amide linkage in this compound by an ester group further reduced the potency. In contrast, replacement of the arachidonoyl side chain by a linolenoyl side chain did not affect the observed potency. N-(Fur-3-ylmethyl) arachidonamide (UCM707), N-(fur-3-ylmethyl)linolenamide and N-(fur-3-ylmethyl)oleamide inhibited anandamide hydrolysis with pI50 values of 4.53, 5.36 and 5.25, respectively. The linolenamide derivative was also found to be a mixed-type inhibitor. It is concluded that the 5-hydroxy group of arachidonoyl-serotonin contributes to, but is not essential for, inhibitory potency at fatty acid amidohydrolase.

New synthetic inhibitors of fatty acid synthase with anticancer activity

Fatty acid synthase (FASN) is a lipogenic enzyme that is highly expressed in different human cancers. Here we report the development of a new series of polyphenolic compounds 5-30 that have been evaluated for their cytotoxic capacity in SK-Br3 cells, a human breast cancer cell line with high FASN expression. The compounds with an IC(50) < 50 μM have been tested for their ability to inhibit FASN activity. Among them, derivative 30 blocks the 90% of FASN activity at low concentration (4 μM), is highly cytotoxic in a broad panel of tumor cells, induces apoptosis, and blocks the activation of HER2, AKT, and ERK pathways. Remarkably, 30 does not activate carnitine palmitoyltransferase-1 (CPT-1) nor induces in mice weight loss, which are the main drawbacks of other previously described FASN inhibitors. Thus, FASN inhibitor 30 may aid the validation of this enzyme as a therapeutic target for the treatment of cancer.

Structure-activity relationship of a new series of reversible dual monoacylglycerol lipase/fatty acid amide hydrolase inhibitors

The two endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), play independent and nonredundant roles in the body. This makes the development of both selective and dual inhibitors of their inactivation an important priority. In this work we report a new series of inhibitors of monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH). Among them, (±)-oxiran-2-ylmethyl 6-(1,1'-biphenyl-4-yl)hexanoate (8) and (2R)-(-)-oxiran-2-ylmethyl(4-benzylphenyl)acetate (30) stand out as potent inhibitors of human recombinant MAGL (IC(50) (8) = 4.1 μM; IC(50) (30) = 2.4 μM), rat brain monoacylglycerol hydrolysis (IC(50) (8) = 1.8 μM; IC(50) (30) = 0.68 μM), and rat brain FAAH (IC(50) (8) = 5.1 μM; IC(50) (30) = 0.29 μM). Importantly, and in contrast to the other previously described MAGL inhibitors, these compounds behave as reversible inhibitors either of competitive (8) or noncompetitive nature (30). Hence, they could be useful to explore the therapeutic potential of reversible MAGL inhibitors.

New serotonin 5-HT(1A) receptor agonists with neuroprotective effect against ischemic cell damage

We report the synthesis of new compounds 4-35 based on structural modifications of different moieties of previously described lead UCM-2550. The new nonpiperazine derivatives, representing second-generation agonists, were assessed for binding affinity, selectivity, and functional activity at the 5-HT(1A) receptor (5-HT(1A)R). Computational β(2)-based homology models of the ligand-receptor complexes were used to explain the observed structure-affinity relationships. Selected candidates were also evaluated for their potential in vitro and in vivo neuroprotective properties. Interestingly, compound 26 (2-{6-[(3,4-dihydro-2H-chromen-2-ylmethyl)amino]hexyl}tetrahydro-1H-pyrrolo[1,2-c]imidazole-1,3(2H)-dione) has been characterized as a high-affinity and potent 5-HT(1A)R agonist (K(i) = 5.9 nM, EC(50) = 21.8 nM) and exhibits neuroprotective effect in neurotoxicity assays in primary cell cultures from rat hippocampus and in the MCAO model of focal cerebral ischemia in rats.

Development of endocannabinoid-based chemical probes for the study of cannabinoid receptors

We report the synthesis of new chemical probes (1a,b, 2a-c, 3a-c) based on the structure of the main endocannabinoids for their use in biological systems directly or via click chemistry. As proof of concept, 2-arachidonyl glyceryl ether based biotinylated 3b enables direct visualization of CB(1) receptor in cells. These results represent the starting point for the development of advanced small molecule chemical probes able to generate valuable information about the cannabinoid receptors.

Novel anti-fatty acid synthase compounds with anti-cancer activity in HER2+ breast cancer

Fatty acid synthase (FASN) expression and activity has emerged as a common phenotype in most human carcinomas, including breast cancer, and its expression is tightly linked to HER2 signaling pathways. The development of inhibitors of FASN activity has consequently appeared as a novel antitarget modality for treating cancer. However, the clinical use of FASN inhibitors, such as cerulenin, C75, and epigallocatechin 3-gallate (EGCG), is limited by anorexia and induced body weight loss or by its low in vivo potency and stability. Here, we summarize the design and development of G28UCM, the lead-compound of a novel family of synthetic FASN inhibitors, with both in vitro and in vivo activity in a human breast cancer model of FASN(+) and HER2(+) .

Development of Fluorescent Ligands for the Human 5-HT1A Receptor

In this work, we report the design and synthesis of a set of fluorescent probes targeting the human 5-HT1A receptor (h5-HT1AR). Among the synthesized compounds, derivative 4 deserves special attention as being a high-affinity ligand (K i = 2 nM) with good fluorescent properties (I em > 1000 au and a fluorescence quantum yield, Φf, of 0.26), which enables direct observation of the h5-HT1AR in cells. Thus, it represents the first efficacious fluorescent probe for the specific labeling of h5-HT1AR in cells. Our results provide the basis for the introduction of a variety of tags in scaffolds of G protein-coupled receptor (GPCR) ligands that enable visualization, covalent binding, or affinity pull-down of receptors. These strategies should contribute to the optimization of the therapeutic exploitation of known or new members of the GPCR superfamily by providing valuable information about their location or level of expression.

Benzimidazole derivatives as new serotonin 5-HT6 receptor antagonists. Molecular mechanisms of receptor inactivation

On the basis of our previously described pharmacophore model for serotonin 5-HT(6) receptor (5-HT(6)R) antagonists, we have designed, synthesized, and pharmacologically characterized a series of benzimidazole derivatives 1-20 that represent a new family of potent antagonists at the human 5-HT(6)R. Site-directed mutagenesis and a beta(2)-adrenoceptor-based homology model of the 5-HT(6)R were used to predict the mode of binding of antagonist SB-258585 and the new synthesized ligands. Substitution of W6.48, F6.52, or N6.55 by Ala fully impedes compound 4 to block 5-HT-induced activation. Thus, we propose that D3.32 in TM 3 anchors the protonated piperazine ring, the benzimidazole ring expands parallel to EL 2 to hydrogen bond N6.55 in TM 6, and the aromatic ring is placed between TMs 3 and 5 in CH(2)-containing compounds and between TMs 3 and 6 in CO-containing compounds. This combined experimental and computational study has permitted to propose the molecular mechanisms by which the new benzimidazole derivatives act as 5-HT(6)R antagonists.

Synthesis of new serotonin 5-HT7 receptor ligands. Determinants of 5-HT7/5-HT1A receptor selectivity

We report the synthesis of a new set of compounds of general structure I (1-20) with structural modifications in the pharmacophoric elements of the previously reported lead UCM-5600. The new derivatives have been evaluated for binding affinity at 5-HT(7) and 5-HT(1A) receptors. The influence of the different structural features in terms of 5-HT(7)/5-HT(1A) receptor affinity and selectivity was analyzed by computational simulations of the complexes between compounds I and beta(2)-based 3-D models of these receptors. Compound 18 (HYD(1) = 1,3-dihydro-2H-indol-2-one; spacer = -(CH(2))(4)-; HYD(2) + HYD(3) = 3,4-dihydroisoquinolin-2(1H)-yl) exhibits high 5-HT(7)R affinity (K(i) = 7 nM) and selectivity over the 5-HT(1A)R (31-fold), and has been characterized as a partial agonist of the human 5-HT(7)R.

Structure-activity relationship of a series of inhibitors of monoacylglycerol hydrolysis--comparison with effects upon fatty acid amide hydrolase

A series of 32 heterocyclic analogues based on the structure of 2-arachidonoylglycerol (2-AG) were synthesized and tested for their ability to inhibit monoacylglycerol lipase and fatty acid amide hydrolase activities. The designed compounds feature a hydrophobic moiety and different heterocyclic subunits that mimic the glycerol fragment. This series has allowed us to carry out the first systematic structure-activity relationship study on inhibition of 2-AG hydrolysis. The most promising compounds were oxiran-2-ylmethyl (5Z,8Z,11Z,14Z)-icosa-5,8,11,14-tetraenoate (1) and tetrahydro-2H-pyran-2-ylmethyl (5Z,8Z,11Z,14Z)-icosa-5,8,11,14-tetraenoate (5). They inhibited cytosolic 2-oleoylglycerol (2-OG) hydrolysis completely (IC50 values of 4.5 and 5.6 muM, respectively). They also blocked, albeit less potently, 2-OG hydrolysis in membrane fractions (IC50 values of 19 and 26 muM, respectively) and anandamide hydrolysis (IC50 values of 12 and 51 muM, respectively). These compounds will be useful in delineating the importance of the cytosolic hydrolytic activity in the regulation of 2-AG levels and, hence, its potential as a target for drug development.

Synthesis of highly substituted enantiopure piperazines and ketopiperazines from vicinal N-sulfinyl diamines

Enantiopure 1-benzyl-2,3-disubstituted piperazines (4) have been synthesized by treatment of N-sulfinyl-N-benzyldiamino alcohols (1) with diethyl oxalate and sodium methoxide followed by reduction with borane. Alternatively, the sulfinamido group was preserved by an N-acylation/cyclization protocol using alpha-chloroacetyl chloride that led to the synthesis of N-sulfinyl ketopiperazines (11). Ensuing elimination of the sulfinyl group with NaH produced imino ketopiperazines (9) that are suitably functionalized for nucleophilic addition to the imino moiety. Stereoselective and high yielding allylation of imino ketopiperazines (9c) was achieved under Barbier conditions using CeCl3.7H2O as the additive.

CB1 and CB2 cannabinoid receptor binding studies based on modeling and mutagenesis approaches

In absence of X ray crystal structures of G-protein coupled receptors (GPCRs)-ligand complexes, computer-aided molecular modeling together with site-directed mutagenesis studies become of great importance in order to provide in-silico predictions that facilitate the development of new ligands. In this context, the present review addresses the application of these strategies to the CB(1) and CB(2) cannabinoid receptors. The combination of these complementary approaches represents a tool of considerable value which has allowed to understand the specific ligand-receptor interactions.

Activation of the endocannabinoid system as a therapeutic approach in a murine model of multiple sclerosis

Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) is a well-characterized murine model of human multiple sclerosis (MS) that closely resembles the chronic and progressive clinical form of the disease. Recent studies have described the involvement of the cannabinoid system in the progression of the disease and the benefits associated with the administration of cannabinoid agonists. With the objective to study whether "indirect" agonists, that is, compounds able to reinforce the physiological endocannabinoid transmission and, therefore, devoid of the psychotropic effects of "direct" agonists, could be suitable agents for the amelioration of MS neurological deficits, we administered the potent and selective anandamide uptake inhibitor UCM707 to TMEV-infected mice. Our results indicate that treatment during established disease significantly improves the motor function of the diseased mice. At the histological level, UCM707 is able to reduce microglial activation, diminish major histocompatibility complex class II antigen expression, and decrease cellular infiltrates in the spinal cord. Additionally, in microglial cells, UCM707 decreases the production of the proinflammatory cytokines tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6; reduces nitric oxide levels and inducible nitric oxide synthase expression; and is able to potentiate the action of a subeffective dose of the endocannabinoid anandamide. Overall, these results suggest that agents able to activate the endocannabinoid system could constitute a new series of drugs for the treatment of MS.

A Three-Dimensional Pharmacophore Model for 5-Hydroxytryptamine6 (5-HT6) Receptor Antagonists

Forty-five structurally diverse 5-hydroxytryptamine(6) receptor (5-HT(6)R) antagonists were selected to develop a 3D pharmacophore model with the Catalyst software. The structural features for antagonism at this receptor are a positive ionizable atom interacting with Asp(3.32), a hydrogen bond acceptor group interacting with Ser(5.43) and Asn(6.55), a hydrophobic site interacting with residues in a hydrophobic pocket between transmembranes 3, 4, and 5, and an aromatic-ring hydrophobic site interacting with Phe(6.52).

Synthesis and Structure−Activity Relationships of a New Model of Arylpiperazines. 8.1Computational Simulation of Ligand−Receptor Interaction of 5-HT1AR Agonists with Selectivity over α1-Adrenoceptors

We have designed and synthesized a new series of arylpiperazines V exhibiting high 5-HT(1A)R affinity and selectivity over alpha(1)-adrenoceptors. The new selective 5-HT(1A)R ligands contain a hydantoin (m = 0) or diketopiperazine (m = 1) moiety and an arylpiperazine moiety separated by one methylene unit (n = 1). The aryl substituent of the piperazine moiety (Ar) consists of different benzofused rings mimicking the favorable voluminous substituents at ortho and meta positions predicted by 3D-QSAR analysis in the previously reported series I. In particular, (S)-2-[[4-(naphth-1-yl)piperazin-1-yl]methyl]-1,4-dioxoperhydropyrrolo[1,2-a]pyrazine [(S)-9, CSP-2503] (5-HT(1A), K(i) = 4.1 nM; alpha(1), K(i) > 1000 nM) has been pharmacologically characterized as a 5-HT(1A)R agonist at somatodendritic and postsynaptic sites, endowed with anxiolytic properties. Ligand (S)-9 is predicted, in computer simulations, to bind Asp(3.32) in TMH 3, Thr(5.39) and Ser(5.42) in TMH 5, and Trp(6.48) in TMH 6. We propose that agonists modify, by means of an explicit hydrogen bond, the conformation of Trp(6.48) from pointing toward TMH 7, in the inactive gauche+ conformation, to pointing toward the ligand binding site, in the active trans conformation.