ABSTRACT
Sigma receptors (SRs), including SR1 and SR2 subtypes, have attracted increasing interest in recent years due to their involvement in a wide range of activities, including the modulation of opioid analgesia, neuroprotection, and potential anticancer activity. In this context, haloperidol (HAL), a commonly used antipsychotic drug, also possesses SR activity and cytotoxic effects. Herein, we describe the identification of novel SR ligands, obtained by a chemical hybridization approach. There wereendowed with pan-affinity for both SR subtypes and evaluated their potential anticancer activity against SH-SY5Y and HUH-7 cancer cell lines. Through a chemical hybridization approach, we identified novel compounds (4d, 4e, 4g, and 4j) with dual affinity for SR1 and SR2 receptors. These compounds were subjected to cytotoxicity testing using a resazurin assay. The results revealed potent cytotoxic effects against both cancer cell lines, with IC50 values comparable to HAL. Interestingly, the cytotoxic potency of the novel compounds resembled that of the SR1 antagonist HAL rather than the SR2 agonist siramesine (SRM), indicating the potential role of SR1 antagonism in their mechanism of action. The further exploration of their structure-activity relationships and their evaluation in additional cancer cell lines will elucidate their therapeutic potential and may pave the way for the development of novel anticancer agents that target SRs.
Subject(s)
Antineoplastic Agents , Drug Design , Haloperidol , Receptors, sigma , Receptors, sigma/metabolism , Receptors, sigma/antagonists & inhibitors , Haloperidol/pharmacology , Haloperidol/analogs & derivatives , Humans , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Line, Tumor , Structure-Activity Relationship , Molecular Structure , Cell Survival/drug effects , Ligands , Cell Proliferation/drug effects , Drug Screening Assays, AntitumorABSTRACT
Neurodegeneration is a slow and progressive loss of neuronal cells or their function in specific regions of the brain or in the peripheral system. Among several causes responsible for the most common neurodegenerative diseases (NDDs), cholinergic/dopaminergic pathways, but also some endogenous receptors, are often involved. In this context, sigma 1 receptor (S1R) modulators can be used as neuroprotective and antiamnesic agents. Herein, we describe the identification of novel S1R ligands endowed with antioxidant properties, potentially useful as neuroprotective agents. We also computationally assessed how the most promising compounds might interact with the S1R protein's binding sites. The in silico predicted ADME properties suggested that they could be able to cross the brain-blood-barrier (BBB), and to reach the targets. Finally, the observation that at least two novel ifenprodil analogues (5d and 5i) induce an increase of the mRNA levels of the antioxidant NRF2 and SOD1 genes in SH-SY5Y cells suggests that they might be effective agents for protecting neurons against oxidative damage.
Subject(s)
Neuroblastoma , Neuroprotective Agents , Receptors, sigma , Humans , Antioxidants/pharmacology , Antioxidants/chemistry , Ligands , Neuroprotection , Neuroprotective Agents/pharmacology , Neuroprotective Agents/chemistry , Receptors, sigma/metabolismABSTRACT
To extend our screening for novel antimycobacterial molecules, we have designed, synthesized, and biologically evaluated a library of 14 new hydrazide derivatives containing 1,3,4-oxadiazole core. A variety of mycobacterial strains, including some drug-resistant strains, were tested for antimycobacterial activity. Among the compounds tested, five showed high antimycobacterial activity (MIC values of 8 µg/mL) against M. tuberculosis H37Ra attenuated strain, and two derivatives were effective (MIC of 4 µg/mL) against pyrazinamide-resistant strains. Furthermore, the novel compounds were tested against the fungal C. albicans strain, showing no antimycotic activity, and thus demonstrating a good selectivity profile. Notably, they also exhibited low cytotoxicity against human SH-SY5Y cells. The molecular modeling carried out suggested a plausible mechanism of action towards the active site of the InhA enzyme, which confirmed our hypothesis. In conclusion, the active compounds were predicted in silico for ADME properties, and all proved to be potentially orally absorbed in humans.
Subject(s)
Mycobacterium tuberculosis , Neuroblastoma , Humans , Antitubercular Agents/chemistry , Hydrazines/pharmacology , Microbial Sensitivity Tests , Neuroblastoma/drug therapy , Fungi , Structure-Activity Relationship , Molecular Docking SimulationABSTRACT
In our continuing effort to develop novel sigma receptor (SR) ligands, we present the design, synthesis and binding studies of a small library of aminopropylcarboxamide derivatives, obtained from a deconstruction of the piperidine ring of previously synthesized piperidine-based compounds. The best results were achieved with benzofuran (5c, 5g) and quinoline (5a, 5e) derivatives. These compounds revealed the highest affinity for both receptor subtypes. In particular, the 3,4-dimethoxyphenyl derivatives 5e and 5g showed the highest selectivity profile for S2R, especially the quinoline derivative 5e exhibited a 35-fold higher affinity for S2R subtype. The cytotoxic activity of aforementioned compounds was evaluated against SKBR3 and MCF7 cell lines, widely used for breast cancer studies. Whereas the potency of 5g was similar that of Siramesine and Haloperidol in both cell lines, compounds 5a, 5c and 5e exhibited a potency at least comparable to that of Haloperidol in SKBR3 cells. A molecular modelling evaluation towards the S2R binding site, confirmed the strong interaction of compound 5e thus justifying its highest S2R affinity.
Subject(s)
Quinolines , Receptors, sigma , Haloperidol , Ligands , Piperidines , Quinolines/pharmacology , Receptors, sigma/metabolism , Structure-Activity RelationshipABSTRACT
Therapies halting the progression of fibrosis are ineffective and limited. Activated myofibroblasts are emerging as important targets in the progression of fibrotic diseases. Previously, we performed a high-throughput screen on lung fibroblasts and subsequently demonstrated that the inhibition of myofibroblast activation is able to prevent lung fibrosis in bleomycin-treated mice. High-throughput screens are an ideal method of repurposing drugs, yet they contain an intrinsic limitation, which is the size of the library itself. Here, we exploited the data from our "wet" screen and used "dry" machine learning analysis to virtually screen millions of compounds, identifying novel anti-fibrotic hits which target myofibroblast differentiation, many of which were structurally related to dopamine. We synthesized and validated several compounds ex vivo ("wet") and confirmed that both dopamine and its derivative TS1 are powerful inhibitors of myofibroblast activation. We further used RNAi-mediated knock-down and demonstrated that both molecules act through the dopamine receptor 3 and exert their anti-fibrotic effect by inhibiting the canonical transforming growth factor ß pathway. Furthermore, molecular modelling confirmed the capability of TS1 to bind both human and mouse dopamine receptor 3. The anti-fibrotic effect on human cells was confirmed using primary fibroblasts from idiopathic pulmonary fibrosis patients. Finally, TS1 prevented and reversed disease progression in a murine model of lung fibrosis. Both our interdisciplinary approach and our novel compound TS1 are promising tools for understanding and combating lung fibrosis.
Subject(s)
Bleomycin/adverse effects , Drug Discovery/methods , Drug Screening Assays, Antitumor/methods , High-Throughput Screening Assays/methods , Idiopathic Pulmonary Fibrosis/chemically induced , Idiopathic Pulmonary Fibrosis/therapy , Lung Diseases/chemically induced , Lung Diseases/therapy , Machine Learning/standards , Myofibroblasts/metabolism , Animals , Cell Differentiation , Humans , Idiopathic Pulmonary Fibrosis/pathology , Lung Diseases/pathology , Mice , TransfectionABSTRACT
Among several potential applications, sigma receptor ligands can be used as antipsychotics, antiamnesics, and against other neurodegenerative disorders as well as neuroprotective agents. We present herein a new series of diazepane-containing derivatives as σR ligands obtained by a conformational expansion approach of our previously synthesized piperidine-based compounds. The best results were reached by benzofurane 2c, 3c and quinoline 2d, 3d-substituted diazepane derivatives, which showed the highest σR affinity. The cytotoxic activities of synthesized compounds were evaluated against two cancer cell lines, and the results indicated that none of the compounds induced significant toxicity in these cells. We also evaluated the antioxidant activity by radical scavenging capacity of our best compounds on ABTS and H2O2. The results obtained reveal that our new derivatives possess an excellent antioxidant profile and could be protective for the cells. Overall, the benzofurane derivative 2c due to its strong interaction with the active site of the receptor, as confirmed by molecular dynamic simulations, emerged as the optimum compound with high σ1R affinity, low cytotoxicity, and a potent antioxidant activity.
ABSTRACT
This study examines in depth benzoxazine nucleus for antimycobacterial property. We synthesized some benzoxazin-2-one and benzoxazin-3-one derivatives, which were tested for activity against a panel of Mycobacterium tuberculosis (Mtb) strains, including H37Ra, H37Rv and some resistant strains. Several compounds displayed a high antimycobacterial activity and the three isoniazid analogue derivatives 8a-c exhibited a MIC range of 0.125-0.250⯵g/mL (0.37-0.75⯵M) against strain H37Ra, therefore lower than the isoniazid reference drug. Two benzoxazin-2-one derivatives, 1c and 5j, together with isoniazid-analogue compound 8a, also revealed low MIC values against resistant strains and proved highly selective for mycobacterial cells, compared to mammalian Vero cells. To predict whether molecule 8a is able to interact with the active site of InhA, we docked it into the crystal structure; indeed, during the molecular dynamic simulation the compound never left the protein pocket. The more active compounds were predicted for ADME properties and all proved to be potentially orally active in humans.
Subject(s)
Antitubercular Agents/chemical synthesis , Benzoxazines/chemistry , Drug Design , Animals , Antitubercular Agents/pharmacology , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Benzoxazines/pharmacology , Binding Sites , Catalytic Domain , Chlorocebus aethiops , Drug Resistance, Bacterial/drug effects , Isoniazid/pharmacology , Microbial Sensitivity Tests , Molecular Docking Simulation , Mycobacterium tuberculosis/drug effects , Oxidoreductases/chemistry , Oxidoreductases/metabolism , Structure-Activity Relationship , Vero CellsABSTRACT
Among several potential applications, sigma receptors (σRs) can be used as neuroprotective agents, antiamnesic, antipsychotics and against other neurodegenerative disorders. On the other hands, antagonists of the GluN2b-subunit-containing-N-methyl-D-aspartate (NMDA) receptors are of major interest for the same purpose, being this subunit expressed in specific areas of the central nervous system and responsible for the excitatory regulation of nerve cells. Under these premises, we have synthesized and biologically tested novel hybrid derivatives obtained from the combination of phenyloxadiazolone and dihydroquinolinone scaffolds with different amine moieties, peculiar of σ2R ligands. Most of the new ligands exhibited a pan-affinity towards both σR subtypes and high affinity against GluN2b subunit. The most promising compounds belong to the dihydroquinolinone series, with the best affinity profile for the cyclohexylpiperazine derivative 28. Investigation on their biological activity showed that the new compounds were able to protect SH-SY5Y cells against oxidative stress induced by hydrogen peroxide treatment. These results proved that our dual σR/GluN2b ligands have beneficial effects in a model of neuronal oxidative stress and can represent strong candidate pharmacotherapeutic agents for minimizing oxidative stress-induced neuronal injuries.
Subject(s)
Antioxidants/pharmacology , Neuroprotective Agents/pharmacology , Oxadiazoles/pharmacology , Quinolones/pharmacology , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Receptors, sigma/antagonists & inhibitors , Antioxidants/chemical synthesis , Antioxidants/chemistry , Benzothiazoles/antagonists & inhibitors , Cell Line, Tumor , Dose-Response Relationship, Drug , Drug Discovery , Humans , Hydrogen Peroxide/antagonists & inhibitors , Ligands , Models, Molecular , Molecular Structure , Neuroprotective Agents/chemical synthesis , Neuroprotective Agents/chemistry , Oxadiazoles/chemical synthesis , Oxadiazoles/chemistry , Oxidative Stress/drug effects , Quinolones/chemical synthesis , Quinolones/chemistry , Structure-Activity Relationship , Sulfonic Acids/antagonists & inhibitorsABSTRACT
BACKGROUND: Superficial wounds that require suturing are often the reason children visit the Paediatric Emergency Department. Suturing is usually accompanied by perilesional administration of lidocaine, a local anaesthetic drug that improves pain tolerance. In paediatric patients, this approach has a low compliance because lidocaine has to be injected, which in children generates fear and anxiety, a sterile anaesthetic gel could improve the child compliance. OBJECTIVE: To develop a sterile and stable sterile gel capable of remaining in place over time for topical anaesthesia. METHOD: Different formulations were analysed by HPLC, by UV and fluorimetric detection. Two different sterilisation methods were tested. MAIN OUTCOME: To maintain the original stability of the gel also after sterilisation process. RESULTS: Four different gels were prepared and analysed; the most stable gel lasts over 3â¯months with a degradation less than 10%. CONCLUSION: The use of Poloxamer 407 guarantees stability of the preparation, showing a reduction in oxidative reaction, and gives the gel the right texture for application to a bleeding wound.
Subject(s)
Epinephrine/chemistry , Gels/chemistry , Lidocaine/chemistry , Tetracaine/chemistry , Anesthetics, Local/chemistry , Chemistry, Pharmaceutical/methods , Pain/drug therapy , Pain Measurement/methodsABSTRACT
The sigma receptor (σR) family has been considered mysterious for a long time. In fact, the σ2R subtype has been cloned only recently, revealing its identity as TMEM97, a NPC1-binding protein involved in cholesterol biosynthesis and implicated in the pathogenesis of cancer and neurologic disorders. With the aim of developing new chemical entities gifted with σR affinity, herein we report the design and synthesis of new piperidine-based alkylacetamide derivatives with mixed affinity towards both σ1 and σ2R subtypes.
Subject(s)
Piperidines/chemistry , Receptors, sigma/drug effects , Cell Line, Tumor , Humans , Ligands , Piperidines/chemical synthesis , Piperidines/pharmacologyABSTRACT
In this work we applied a blend of computational and synthetic techniques with the aim to design, synthesize, and characterize new σ1 receptor (σ1R) ligands. Starting from the structure of previously reported, high-affinity benzoxazolone-based σ1 ligands, the three-dimensional homology model of the σ1R was exploited for retrieving the molecular determinants to fulfill the optimal pharmacophore requirements. Accordingly, the benzoxazolone moiety was replaced by other heterocyclic scaffolds, the relevant conformational space in the σ1R binding cavity was explored, and the effect on σ1R binding affinity was ultimately assessed. Next, the compounds designed in silico were synthesized, and their affinity and selectivity toward σ1 and σ2 receptors were tested. Finally, a representative series of best σ1R binders were assayed for cytotoxic activity on the SH-SY5Y human neuroblastoma cell line. Specifically, the new 4-phenyloxazolidin-2-one derivatives 2b (i.e., (R)-2b and (S)-2b) emerged as potential leads for further development as σ1R agents, as they were found endowed with the highest σ1R affinity (Kiσ1 values in the range 0.95-9.3 nM), and showed minimal cytotoxic levels exhibited in the selected, cell-based test, in line with a σ1R agonist behavior.
Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Computer-Aided Design , Heterocyclic Compounds/chemical synthesis , Heterocyclic Compounds/pharmacology , Receptors, sigma/metabolism , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Cell Line, Tumor , Chemistry Techniques, Synthetic , Heterocyclic Compounds/chemistry , Heterocyclic Compounds/metabolism , Humans , Ligands , Molecular Docking Simulation , Protein Conformation , Receptors, sigma/chemistry , Structure-Activity RelationshipABSTRACT
N(1)-[1-[1-aryl-3-[4-(1H-imidazol-1-yl)phenyl]-3-oxo]propyl]-pyridine-2-carboxamidrazone derivatives were design, synthesized and tested for their in vitro antimycobacterial activity. The new compounds showed a moderate antimycobacterial activity against the tested strain of Mycobacterium tuberculosis H37Ra and a significant antimycobacterial activity against several mycobacteria other than tuberculosis strains.
Subject(s)
Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Bacteria/drug effects , Fungi/drug effects , Imidazoles/pharmacology , Pyridines/pharmacology , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Antifungal Agents/chemical synthesis , Antifungal Agents/chemistry , Dose-Response Relationship, Drug , Imidazoles/chemical synthesis , Imidazoles/chemistry , Microbial Sensitivity Tests , Molecular Structure , Pyridines/chemical synthesis , Pyridines/chemistry , Structure-Activity RelationshipABSTRACT
We report the design, synthesis and binding evaluation against σ1 and σ2 receptors of a series of new piperidine-4-carboxamide derivatives variously substituted on the amide nitrogen atom. Specifically, we assessed the effects exerted on σ receptor affinity by substituting the N-benzylcarboxamide group present on a series of compounds previously synthesized in our laboratory with different cyclic or linear moieties. The synthesized compounds 2a-o were tested to estimate their affinity and selectivity toward σ1 and σ2 receptors. Very high σ1 affinity (Ki = 3.7 nM) and Kiσ2/Kiσ1 selectivity ratio (351) were found for the tetrahydroquinoline derivative 2k, featuring a 4-chlorobenzyl moiety linked to the piperidine nitrogen atom.
Subject(s)
Piperidines/pharmacology , Receptors, sigma/antagonists & inhibitors , Dose-Response Relationship, Drug , Humans , Ligands , Models, Molecular , Molecular Structure , Piperidines/chemical synthesis , Piperidines/chemistry , Structure-Activity Relationship , Sigma-1 ReceptorABSTRACT
We describe here the synthesis and the binding interaction with σ1 and σ2 receptors of a series of new arylcarboxamide derivatives variously substituted on the aromatic portions. Maintaining a partial scaffold of a series of compounds previously synthesized by us, we evaluate the effect of the substitution on σ binding. The synthesized compounds have been tested to estimate their affinity and selectivity toward σ1 and σ2 receptors. Two out of 16 derivatives showed an interesting σ1 affinity (21.2 and 13.6 nM-compounds 2m and 2p) and a good selectivity (Ki(σ2)/Ki(σ1) >140 and >40, respectively).
Subject(s)
Amides/pharmacology , Receptors, sigma/metabolism , Amides/chemical synthesis , Amides/chemistry , Animals , Binding Sites/drug effects , Dose-Response Relationship, Drug , Guinea Pigs , Ligands , Molecular Dynamics Simulation , Molecular Structure , Rats , Structure-Activity Relationship , Sigma-1 ReceptorABSTRACT
Originally considered an enigmatic polypeptide, the σ(1) receptor has recently been identified as a unique ligand-regulated protein. Many studies have shown the potential of σ(1) receptor ligands for the treatment of various diseases of the central nervous system (CNS); nevertheless, almost no information about the 3D structure of the receptor and/or the possible modes of interaction of the σ(1) protein with its ligands have been unveiled so far. With the present work we validated our σ(1) 3D homology model and assessed its reliability as a platform for σ(1) ligand structure-based drug design. To this purpose, the 3D σ(1) model was exploited in the design of 33 new σ(1) ligands and in their ranking for receptor affinity by extensive molecular dynamics simulation-based free energy calculations. Also, the main interactions involved in receptor/ligand binding were analyzed by applying a per residue free energy deconvolution and in silico alanine scanning mutagenesis calculations. Subsequently, all compounds were synthesized in our laboratory and tested for σ(1) binding activity in vitro. The agreement between in silico and in vitro results confirms the reliability of the proposed σ(1) 3D model in the a priori prediction of the affinity of new σ(1) ligands. Moreover, it also supports and corroborates the currently available biochemical data concerning the σ(1) protein residues considered essential for σ(1) ligand binding and activity.
Subject(s)
Computer-Aided Design , Drug Design , Receptors, sigma/metabolism , Computer Simulation , Humans , Ligands , Models, Molecular , Molecular Dynamics Simulation , Mutagenesis , Mutation/genetics , Protein Binding , Quantitative Structure-Activity Relationship , Receptors, sigma/chemistry , Receptors, sigma/geneticsABSTRACT
This study presents for the first time the 3D model of the σ1 receptor protein as obtained from homology modeling techniques, shows the applicability of this structure to docking-based virtual screening, defines a computational strategy to optimize the results based on a combination of 3D pharmacophore-based docking and MM/PBSA free energy of binding scoring, and provides evidence that these in silico models and recipes are powerful tools on which virtual screening of new σ1 ligands can be based. In particular, the validation of the applicability of docking-based virtual screening to homology models is of utmost importance, since no crystal structure is available to date for the σ1 receptor, and this missing information still constitutes a major hurdle for a rational ligand design for this important protein target.
ABSTRACT
In this work we developed a 3D-pharmacophore model for sigma(2) receptor based on 19 benzooxazolone derivatives. The best 3D-pharmacophore hypothesis, consisting of five features: a positive ionizable, a hydrogen bond acceptor, a hydrophobic aromatic, a hydrophobic aliphatic, and a generic hydrophobic provided a 3D-QSAR model with a correlation coefficient of 0.97 and a RMSD of 0.48.
Subject(s)
Models, Chemical , Models, Molecular , Oxazolone/chemistry , Receptors, sigma/antagonists & inhibitors , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Ligands , Oxazolone/chemical synthesis , Oxazolone/pharmacology , Quantitative Structure-Activity Relationship , Receptors, sigma/metabolismABSTRACT
In order to investigate the molecular features involved in sigma receptors (sigma-Rs) binding, new compounds based on arylalkylaminoalcoholic, arylalkenyl- and arylalkylaminic scaffolds were synthesized and their affinity towards sigma(1)- and sigma(2)-Rs subtypes was evaluated. The most promising compounds were also screened for their affinity at micro-opioid, delta-opioid and kappa-opioid receptors. Biological results are herein presented and discussed.
Subject(s)
Amines/chemistry , Amines/pharmacology , Receptors, sigma/metabolism , Alkenes/chemistry , Alkenes/pharmacology , Amino Alcohols/chemistry , Amino Alcohols/pharmacology , Animals , Guinea Pigs , Hydrocarbons, Aromatic/chemistry , Hydrocarbons, Aromatic/pharmacology , Ligands , Models, Molecular , Protein Binding , Rats , Receptors, Opioid/metabolism , Structure-Activity RelationshipABSTRACT
2-Aryl-3-(1H-imidazol-1-yl and 1H-1,2,4-triazol-1-yl)-1H-indole derivatives were synthesized and tested for their in-vitro antifungal and antimycobacterial activities. These indole derivatives were devoid of antifungal activity against the tested strains of Candida spp. Yet, they exhibited an interesting antitubercular activity against Mycobacterium tuberculosis reference strain H(37)Rv.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Antifungal Agents/chemical synthesis , Candida/drug effects , Chemistry, Pharmaceutical/methods , Indoles/chemical synthesis , Mycobacterium tuberculosis/drug effects , Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Indoles/pharmacology , Microbial Sensitivity Tests , Molecular Structure , Structure-Activity RelationshipABSTRACT
Novel benzo[d]oxazol-2(3H)-one derivatives were designed and synthesized, and their affinities against sigma receptors were evaluated. On the basis of 31 compounds, a three-dimensional pharmacophore model for the sigma(1) receptor binding site was developed using the Catalyst 4.9 software package. The best 3D pharmacophore hypothesis, consisting of one positive ionizable, one hydrogen bond acceptor, two hydrophobic aromatic, and one hydrophobic features provided a 3D-QSAR model with a correlation coefficient of 0.89. The best hypothesis was also validated by three independent methods, i.e., the Fisher randomization test included in the CatScramble functionality of Catalyst, the leave-one-out test, and activity prediction of an additional test set. The achieved results will allow researchers to use this 3D pharmacophore model for the design and synthesis of a second generation of high affinity sigma(1) ligands, as well as to discover other lead compounds for this class of receptors.