Selective Compounds Research Articles

Anti-inflammatory potential of selective small compounds by targeting TNF-α & NF-kB signaling: a comprehensive molecular docking and simulation study

Tumor necrosis factor alpha (TNF-α) is the major cause of inflammation in autoimmune diseases like rheumatoid arthritis (RA). It’s mechanisms of signal transduction through nuclear factor kappa B (NF-kB) pathway via small molecules such as metabolite crosstalk are still elusive. In this study, we have targeted TNF-α and NF-kB through metabolites of RA, to inhibit TNF-α activity and deter NF-kB signaling pathways, thereby mitigating the disease severity of RA. TNF-α and NF-kB structure was obtained from PDB database and metabolites of RA were selected from literature survey. In-silico studies were carried out by molecular docking using AutoDock Vina software and further, known TNF-α and NF-kB inhibitors were compared and revealed metabolite’s capacity to targets the respective proteins. Most suitable metabolite was then validated by MD simulation to verify its efficiency against TNF-α. Total 56 known differential metabolites of RA were docked with TNF-α and NF-kB compared to their corresponding inhibitor compounds. Four metabolites such as Chenodeoxycholic acid, 2-Hydroxyestrone, 2-Hydroxyestradiol (2-OHE2), and 16-Hydroxyestradiol were identified as a common TNF-α inhibitor’s having binding energies ranging from −8.3 to −8.6 kcal/mol, followed by docking with NF-kB. Further, 2-OHE2 was selected because of having binding energy −8.5 kcal/mol, found to inhibit inflammation and the effectiveness was validated by root mean square fluctuation, radius of gyration and molecular mechanics with generalized born and surface area solvation against TNF-α. Thus 2-OHE2, an estrogen metabolite was identified as the potential inhibitor, attenuated inflammatory activation and can be utilized as a therapeutic target to disseminate severity of RA.

Identification of Efflux Substrates Using a Riboswitch-Based Reporter in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is intrinsically resistant to many classes of antibiotics, reflecting the restrictive nature of its outer membrane and the action of its numerous efflux systems. However, the dynamics of compound uptake, retention, and efflux in this bacterium remain incompletely understood. Here, we exploited the sensor capabilities of a Z-nucleotide-sensing riboswitch to create an experimental system able to identify physicochemical and structural properties of compounds that permeate the bacterial cell, avoid efflux, and perturb the folate cycle or de novo purine synthesis. In the first step, a collection of structurally diverse compounds enriched in antifolate drugs was screened for ZTP (5-aminoimidazole-4-carboxamide riboside 5'-triphosphate) riboswitch reporter activity in efflux-deficient P. aeruginosa, allowing us to identify compounds that entered the cell and disrupted the folate pathway. These initial hits were then rescreened using isogenic efflux-proficient bacteria, allowing us to separate efflux substrates from efflux avoiders. We confirmed this categorization by measuring intracellular levels of select compounds in the efflux-deficient and -proficient strain using high-resolution liquid chromatography-mass spectrometry (LC-MS). This simple yet powerful method, optimized for high-throughput screening, enables the discovery of numerous permeable compounds that avoid efflux and paves the way for further refinement of the physicochemical and structural rules governing efflux in this multidrug-resistant Gram-negative pathogen. IMPORTANCE Treatment of Pseudomonas aeruginosa infections has become increasingly challenging. The development of novel antibiotics against this multidrug-resistant bacterium is a priority, but many drug candidates never achieve effective concentrations in the bacterial cell due to its highly restrictive outer membrane and the action of multiple efflux pumps. Here, we develop a robust and simple reporter system in P. aeruginosa to screen chemical libraries and identify compounds that either enter the cell and remain inside or enter the cell and are exported by efflux systems. This approach enables the development of rules of compound uptake and retention in P. aeruginosa that will lead to more rational design of novel antibiotics.

Molecular Modeling, Docking, and QSAR Studies on A Series of N-arylsulfonyl-N-2-pyridinyl-piperazines Analogs Acting as Anti-Diabetic Agents

The Molecular structure of compounds contains a lot of information that can be used further. A classical Quantitative Structure Activity Relationship (QSAR) method was used to decode that information based on the descriptors. The study was performed on a mono-substituted series of Glucokinase-Glucokinase regulatory protein inhibitors (GK-GKRP/GCKR). A sequential application of the statistical method, both linear and nonlinear, has been used in the study which includes Multiple Linear Regression (MLR), Partial Least Square (PLS), and Artificial Neural Network (ANN). The developed model was validated using various statistical methods to evidently prove its reliability and precision. This knowledge will be used to design a new compound. Docking studies will be performed to establish the binding pattern of the designed compound. The prophetic power and robustness of the model containing 26 compounds in the training set were proven by the various statistical parameter s value: 0.30, F-value: 41.8, r: 0.94, r2: 0.88, r2CV: 0.77. The model gives insight into the various descriptors that are selected for the present study. The present study not only shows the contribution of various substituents in the biological activity but also indicates the changes that can be done to design the new potent molecules with more selectivity and less toxicity. HIGHLIGHTS The enzyme glucokinase (GCK) is responsible for maintaining the body's normal glucose homeostasis. Hypertriglyceridemia, hyperinsulinemia, and T2D are all triggered by GCK dysfunction or dysregulation An inhibitor of the glucokinase enzyme (GCK), which is only present in hepatocytes and is in charge of glucose metabolism, is encoded by the glucokinase regulator (GCKR) gene The designed model gives insight into the various descriptors that are selected for the present study. The present study not only shows the contribution of various substituents in the biological activity but also indicates the changes that can be done to design the new potent molecules with more selectivity and less toxicity Small compounds have been discovered that specifically bind to GKRP and lower blood sugar levels GRAPHICAL ABSTRACT

Design, synthesis, molecular docking studies and biological evaluation of thiazole carboxamide derivatives as COX inhibitors

BackgroundNonsteroidal anti-inflammatory drugs (NSAIDs) have been the most commonly used class of medications worldwide for the last three decades.ObjectivesThis study aimed to design and synthesize a novel series of methoxyphenyl thiazole carboxamide derivatives and evaluate their cyclooxygenase (COX) suppressant and cytotoxic properties.MethodsThe synthesized compounds were characterized using 1H, 13C-NMR, IR, and HRMS spectrum analysis and were evaluated for their selectivity towards COX-1 and COX-2 using an in vitro COX inhibition assay kit. Besides, their cytotoxicity was evaluated using the Sulforhodamine B (SRB) assay. Moreover, molecular docking studies were conducted to identify the possible binding patterns of these compounds within both COX-1 and COX-2 isozymes, utilizing human X-ray crystal structures. The density functional theory (DFT) analysis was used to evaluate compound chemical reactivity, which was determined by calculating the frontier orbital energy of both HOMO and LUMO orbitals, as well as the HOMO–LUMO energy gap. Finally, the QiKProp module was used for ADME-T analysis.ResultsThe results revealed that all synthesized molecules have potent inhibitory activities against COX enzymes. The percentage of inhibitory activities at 5 µM concentration against the COX2 enzyme was in the range of 53.9–81.5%, while the percentage against the COX-1 enzyme was 14.7–74.8%. That means almost all of our compounds have selective inhibition activities against the COX-2 enzyme, and the most selective compound was 2f, with selectivity ratio (SR) value of 3.67 at 5 µM concentration, which has a bulky group of trimethoxy on the phenyl ring that could not bind well with the COX-1 enzyme. Compound 2h was the most potent, with an inhibitory activity percentage at 5 µM concentration of 81.5 and 58.2% against COX-2 and COX-1, respectively. The cytotoxicity of these compounds was evaluated against three cancer cell lines: Huh7, MCF-7, and HCT116, and negligible or very weak activities were observed for all of these compounds except compound 2f, which showed moderate activities with IC50 values of 17.47 and 14.57 µM against Huh7 and HCT116 cancer cell lines, respectively. Analysis of the molecular docking suggests 2d, 2e, 2f, and 2i molecules were bound to COX-2 isozyme favorably over COX-1 enzyme, and their interaction behaviors within COX-1 and COX-2 isozymes were comparable to celecoxib, as an ideal selective COX-2 drug, which explained their high potency and COX-2 selectivity. The molecular docking scores and expected affinity using the MM-GBSA approach were consistent with the recorded biological activity. The calculated global reactivity descriptors, such as HOMO and LUMO energies and the HOMO–LUMO gaps, confirmed the key structural features required to achieve favorable binding interactions and thus improve affinity. The in silico ADME-T studies asserted the druggability of molecules and have the potential to become lead molecules in the drug discovery process.ConclusionIn general, the series of the synthesized compounds had a strong effect on both enzymes (COX-1 and COX-2) and the trimethoxy compound 2f was more selective than the other compounds.

Identifying a selective inhibitor of autophagy that targets ATG12-ATG3 protein-protein interaction

ABSTRACT Macroautophagy/autophagy is a catabolic process by which cytosolic content is engulfed, degraded and recycled. It has been implicated as a critical pathway in advanced stages of cancer, as it maintains tumor cell homeostasis and continuous growth by nourishing hypoxic or nutrient-starved tumors. Autophagy also supports alternative cellular trafficking pathways, providing a mechanism of non-canonical secretion of inflammatory cytokines. This opens a significant therapeutic opportunity for using autophagy inhibitors in cancer and acute inflammatory responses. Here we developed a high throughput compound screen to identify inhibitors of protein-protein interaction (PPI) in autophagy, based on the protein-fragment complementation assay (PCA). We chose to target the ATG12-ATG3 PPI, as this interaction is indispensable for autophagosome formation, and the analyzed structure of the interaction interface predicts that it may be amenable to inhibition by small molecules. We screened 41,161 compounds yielding 17 compounds that effectively inhibit the ATG12-ATG3 interaction in the PCA platform, and which were subsequently filtered by their ability to inhibit autophagosome formation in viable cells. We describe a lead compound (#189) that inhibited GFP-fused MAP1LC3B/LC3B (microtubule associated protein 1 light chain 3 beta) puncta formation in cells with IC50 value corresponding to 9.3 μM. This compound displayed a selective inhibitory effect on the growth of autophagy addicted tumor cells and inhibited secretion of IL1B/IL-1β (interleukin 1 beta) by macrophage-like cells. Compound 189 has the potential to be developed into a therapeutic drug and its discovery documents the power of targeting PPIs for acquiring specific and selective compound inhibitors of autophagy. Abbreviations: ANOVA: analysis of variance; ATG: autophagy related; CQ: chloroquine; GFP: green fluorescent protein; GLuc: Gaussia Luciferase; HEK: human embryonic kidney; IL1B: interleukin 1 beta; LPS: lipopolysaccharide; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; PCA: protein-fragment complementation assay; PDAC: pancreatic ductal adenocarcinoma; PMA: phorbol 12-myristate 13-acetate; PPI: protein-protein interaction. VCL: vinculin.

Application of Halides Complexes of Ruthenium (II) in Metallopharmaceuticals and in Material Science: Part-I

Ruthenium readily forms coordinate-complexes and these complexes have their applications in diverse fields. A survey of literature shows that designing of new ligands that can be complexed with Ruthenium (Ru) in various oxidation states can lead to development of new materials with diverse applications. In 21st century the gravity of approach of material science together with computer science has shifted from, how to make a molecule to what molecule to make, in other words molecular design. And now these are also quantized. As we know that physics, chemistry, and biology were explored at atomic levels and finally mathematical data were fed to grow required software for aimed simulations. The aim of present study is to study halides and mixed halides of Ru(II), which more precisely can help in the development of new Ru(II) complexes of desired application and or can help in fine tuning the property of pre-existing Ru(II) complexes. Thus, this study of atomistic details of halides of Ru(II) compounds along with construction of molecular orbital diagram at a glance will provide an insight of physicochemical, biochemical, electrochemical, thermochemical, magnetic, spectrochemical, catalytic, photoactive, and materialistic details. And this will help to solve the difficulties of synthesis of various complexes yet not synthesized. We know that all chemical reaction of complex compounds will be affected firstly by availability of vacant orbital(s) on metal ion (Ru2+) and secondly by the easiness of donation of electron pair(s) by ligands as we have also studied cloud-expanding effect, nephelauxetic effect, and electrochemical series of these Ruthenium(II) halides. The substitution reaction of complex compounds will also be mechanized and new substitution products (compounds) can also be prepared as topological analysis have also been made, those yet cannot synthesize by ordinary methods in required time and required cost too. Hence the halides of Ru(II) studied firstly. With the help of results of these studies, we will able to study complexation of these halides with selective ligands to form selective complex compounds of Ru(II) yet not prepared or have difficulties in preparation.

Mitochondria-Targeted Curcumin: A Potent Antibacterial Agent against Methicillin-Resistant Staphylococcus aureus with a Possible Intracellular ROS Accumulation as the Mechanism of Action

Mitocurcumin (a triphenylphosphonium curcumin derivative) was previously reported as a selective antitumoral compound on different cellular lines, as well as a potent bactericidal candidate. In this study, the same compound showed strong antimicrobial efficacy against different strains of methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentration was identical for all tested strains (four strains of MRSA and one strain of methicillin-sensitive Staphylococcus aureus), suggesting a new mechanism of action compared with usual antibacterial agents. All tested strains showed a significant sensitivity in the low micromolar range for the curcumin-triphenylphosphonium derivative. This susceptibility was modulated by the menadione/glutathione addition (the addition of glutathione resulted in a significant increase in minimal inhibitory concentration from 1.95 to 3.9 uM, whereas adding menadione resulted in a decrease of 0.49 uM). The fluorescence microscopy showed a better intrabacterial accumulation for the new curcumin-triphenylphosphonium derivative compared with simple curcumin. The MitoTracker staining showed an accumulation of reactive oxygen species (ROS) for a S. pombe superoxide dismutase deleted model. All results suggest a new mechanism of action which is not influenced by the acquired resistance of MRSA. The most plausible mechanism is reactive oxygen species (ROS) overproduction after a massive intracellular accumulation of the curcumin-triphenylphosphonium derivative.

Controlling Ibrutinib's Conformations about Its Heterobiaryl Axis to Increase BTK Selectivity.

Ibrutinib is a covalent BTK inhibitor that is approved for several indications in oncology. Ibrutinib possesses significant off-target activities toward many kinases, often leading to adverse events in patients. While there have been robust medicinal chemistry efforts leading to more selective second-generation BTK inhibitors, there remains a need for new strategies to rapidly improve the selectivity of kinase inhibitors. An analysis of PDB data revealed that ibrutinib binds BTK in dihedral conformations that are orthogonal of ibrutinib's predicted low energy conformational range. Synthesis of a series of analogues with ground state conformations shifted toward orthogonality led to the discovery of an analogue with two incorporated ortho-methyl groups that possessed markedly increased BTK selectivity. This work suggests that conformational control about a prospective atropisomeric axis represents a strategy to rapidly program a compound's selectivity toward a given target.

A Unit Process Approach to Nontarget Screening of Organic Contaminants during Urine Treatment

Urine treatment has expanded over the past few decades; however, widespread implementation requires rigorous, generalizable comparisons between selective nutrient separation and organic compound mitigation. This study describes and demonstrates an enrichment ratio framework, defined as the relative concentration changes of nutrients (nitrogen or phosphorus) with organic compounds analyzed via high-resolution mass spectrometry. Nontarget analysis enabled comparison of the effects of urine treatment processes (e.g., ion exchange, freeze–thaw, activated carbon, struvite precipitation) on organic compounds. In total, we considered 14 treatment scenarios, including six unit processes for acidified urine and eight for hydrolyzed urine. Acidified and hydrolyzed urine were characterized longitudinally, and each of the two urine types remained stable in terms of the organic compound profile (>79% similarity) over several weeks. Unit processes with mean enrichment ratios (ER) that involved more than a 2-fold concentration change (ER > 2 or ER < 0.5) were considered high priority and were further separated into cases in which organic compounds were concentrated (ER > 2) or removed (ER < 0.5) for various unit processes. Whereas ER values are typically calculated only for compounds present in both the influent and effluent streams, we also analyzed compounds that were detected in only influent or only effluent added. Results from the target analysis of six compounds generally corroborated the nontarget results. Ultimately, our approach to simultaneously characterizing both nutrients and organic compounds through urine processing steps can inform and advance the implementation of urine resource recovery.

Acylpyrazoline-Based Third-Generation Selective Antichlamydial Compounds with Enhanced Potency.

Chlamydiae are obligate intracellular Gram-negative bacteria and widespread pathogens in humans and animals. Broad-spectrum antibiotics are currently used to treat chlamydial infections. However, broad-spectrum drugs also kill beneficial bacteria. Recently, two generations of benzal acylhydrazones have been shown to selectively inhibit chlamydiae without toxicity to human cells and lactobacilli, which are dominating, beneficial bacteria in the vagina of reproductive-age women. Here, we report the identification of two acylpyrazoline-based third-generation selective antichlamydials (SACs). With minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of 10-25 μM against Chlamydia trachomatis and Chlamydia muridarum, these new antichlamydials are 2- to 5-fold more potent over the benzal acylhydrazone-based second-generation selective antichlamydial lead SF3. Both acylpyrazoline-based SACs are well tolerated by Lactobacillus, Escherichia coli, Klebsiella, and Salmonella as well as host cells. These third-generation selective antichlamydials merit further evaluation for therapeutic application.

Discovery and characterization of antidepressant mediated activation of 5-HT1E and 5-HT1F receptors.

Of the 13 serotonin (5-hydroxytryptamine, 5-HT) receptors in humans, the 5-HT1E and 5-HT1F subtypes (1E and 1F, respectively), are understudied G protein-coupled receptors with high sequence identity among themselves, and to a lesser degree, the other 5-HT1 receptor subtypes. While 1F is a validated target for anti-migraine drugs, the physiological function of 1E remains unknown due to a lack of rodent orthologs and selective compounds. To expand the repertoire of potential chemical scaffolds that could be used to generate 1E- and 1F-selective compounds, we screened a small library of medications and research compounds with known activities at various aminergic receptors. This screen led us to discover that a series of clinically-used drugs featuring a tetracyclic scaffold are high-affinity agonists at 1E and 1F, while they have generally been reported as pan-aminergic antagonists. Seeking to elucidate their mechanisms, we determined structures of 5-HT1E complexed with Gi1 and bound by two of these drugs at 3.31 and 3.28 Å. These structures reveal unambiguous binding poses that demonstrate key interactions with binding pocket residues that confer high affinity in a ligand-specific fashion, and lay the stage for the generation of 1E-specific agonists for physiological studies. Additionally, our functional work offers a putative mechanism of action for the reported anti-migraine activities of the medications characterized in this study.

Small molecules modulating force production: A new perspective against myosin-associated diseases.

Myosins are ATP-dependent molecular motors involved in almost all processes of life. These motors are associated with various human diseases such as various cardiomyopathies, spasticity, deafness or malaria. Nowadays, the most promising approach to treat myosin-associated diseases is the design of small-molecule drugs able to specifically modulate the force produced by these motors. Camzyos (mavacamten) is a specific inhibitor recently approved by the FDA to treat adults with symptomatic class II-III obstructive hypertrophic cardiomyopathy. Omecamtiv mecarbil (OM) also targets β-cardiac myosin but in this case, it is an activator of contraction, currently in late Phase 3 for heart failure. Here we present how a methodology combining X-ray crystallography, molecular dynamics and functional assays allows to study the mechanism of action of some of these compounds. We have determined that despite their antagonistic effects on force production, OM and Mava surprisingly target the same pocket. MPH-220 is a Blebbistatin derivative identified as an inhibitor of skeletal myosin-2 (SkMyo2) and a promising treatment against muscle spasticity. Structures of other inhibitors bound in this pocket with distinct IC50 for three muscle myosins have also provided clues about the parameters that control potency and specificity. KNX-002 is a new inhibitor of Plasmodium falciparum myosin A (PfMyoA). PfMyoA is essential for both red blood cells invasion and parasite motility and is a first-order pharmacological target against malaria. Our structure of PfMyoA complexed to KNX-002 shows how the inhibitor selectively targets an undescribed pocket in the motor, sequestering the myosin in a state detached from actin and preventing hydrolysis. Altogether, these results show how small molecules modulating the force produced by myosins are promising avenues to treat myosin-associated diseases and opens up new approaches to the design of more selective and potent compounds.

Effective adsorption of salvianolic acids with phenylboronic acid functionalized polyethyleneimine-intercalated montmorillonite

It is important to separate salvianolic acids from Danshen owing to their significant therapy-related activities of cardiovascular and cerebrovascular diseases. In this study, phenylboronic acid functionalized polyethyleneimine-intercalated montmorillonite (PAPIM) was successfully synthesized via intercalation and amidation to capture salvianolic acid A (SAA), salvianolic acid B (SAB) and rosmarinic acid (RA) effectively. Adsorption of three salvianolic acids kinetically follows a pseudo-second-order model. The maximum adsorption capacities can be determined to be 1.285, 0.692 and 1.154 mmol/g for SAA, SAB and RA by Langmuir adsorption model, respectively. Comprehensive factors of function groups of adsorbents and structure of phenolic acids result in the affinity order of adsorbent for phenolic acids: SAA > SAB > RA > other phenolic acids with simple structure. Different dominant processes lead to different adsorption thermodynamics of three salvianolic acids. It is found that the adsorption mechanism includes covalent bond, electrostatic interaction, hydrogen bond and π-π stacking interaction. Remarkably, boronic acid affinity and electrostatic interaction play the important role in the selective adsorption process, which is verified by density functional theory (DFT) calculations. This work highlights that PAPIM is a promising adsorbent to realize effective separation of salvianolic acids and provides an alternative potential strategy to selective separate certain compound with multiple synergetic interactions.

Screening through Lead Optimization of High Affinity, Allosteric Cyclin-Dependent Kinase 2 (CDK2) Inhibitors as Male Contraceptives That Reduce Sperm Counts in Mice.

Although cyclin-dependent kinase 2 (CDK2) is a validated target for both cancer and contraception, developing a CDK2 inhibitor with exquisite selectivity has been challenging due to the structural similarity of the ATP-binding site, where most kinase inhibitors bind. We previously discovered an allosteric pocket in CDK2 with the potential to bind a selective compound and then discovered and structurally confirmed an anthranilic acid scaffold that binds this pocket with high affinity. These allosteric inhibitors are selective for CDK2 over structurally similar CDK1 and show contraceptive potential. Herein, we describe the screening and optimization that led to compounds like EF-4-177 with nanomolar affinity for CDK2. EF-4-177 is metabolically stable, orally bioavailable, and significantly disrupts spermatogenesis, demonstrating this series' therapeutic potential. This work details the discovery of the highest affinity allosteric CDK inhibitors reported and shows promise for this series to yield an efficacious and selective allosteric CDK2 inhibitor.

Association between urinary phthalate biomarker concentrations and adiposity among postmenopausal women

BackgroundObesity is a leading risk factor for chronic diseases, potentially related to excess abdominal adiposity. Phthalates are environmental chemicals that have been suggested to act as obesogens, driving obesity risk. For the associations between phthalates and adiposity, prior studies have focused primarily on body mass index. We hypothesize that more refined measures of adiposity and fat distribution may provide greater insights into these associations given the role of central adiposity in chronic disease risk. ObjectivesTo evaluate associations between urinary phthalate biomarkers and both visceral and subcutaneous adipose tissue (VAT and SAT) among postmenopausal women enrolled in the Women's Health Initiative (WHI). MethodsWe included 1125 WHI participants with available, coincident measurements of urinary phthalate biomarkers (baseline, year 3) and VAT and SAT (baseline, year 3, year 6). VAT and SAT measurements were estimated from DXA scans. Multilevel mixed-effects models estimated the prospective associations between urinary phthalate biomarkers at baseline and VAT and SAT three years later. ResultsIn multivariable adjusted models, we observed positive associations between some phthalate biomarkers, including the sum of di-isobutyl phthalate (ΣDiBP) biomarkers, MCNP, and ΣDEHP, with VAT three years later. For example, we observed positive associations between concentrations of ΣDiBP and VAT (Q4 vs Q1 β = 7.15, 95% CI -1.76-16.06; Q3 vs Q1 β = 10.94, 95% CI 3.55–18.33). Associations were generally attenuated but remained significant after additional adjustment for SAT. MBzP was positively associated with SAT. Other phthalate biomarkers investigated (MEP, MCOP, MCPP, ΣDBP) were not significantly associated with VAT or SAT. DiscussionBased on robust measures of adiposity, this study provides supportive evidence that higher urinary concentrations of select phthalate compounds were associated with higher VAT levels over time in postmenopausal women. Efforts to replicate these findings are needed.

Importance of receptor expression in the classification of novel ligands at the M2 muscarinic acetylcholine receptor.

Affinity-based, selective orthosteric ligands for the muscarinic acetylcholine receptors (mAChRs) are difficult to develop due to high sequence homology across the five subtypes. Selectivity can also be achieved via the selective activation of a particular subtype or signalling pathway. Promisingly, a prior study identified compounds 6A and 7A as functionally selective and Gi biased compounds at the M2 mAChR. Here, we have investigated the activation of individual G protein subfamilies and the downstream signalling profiles of 6A and 7A at the M2 mAChR. G protein activation was measured with the TRUPATH assay in M2 mAChR FlpIn CHO cells. Activity in downstream signalling pathways was determined using the cAMP CAMYEL BRET sensor and assay of ERK 1/2 phosphorylation. M2 mAChRs coupled to Gɑi1, GɑoA and Gɑs, but not Gɑq, in response to canonical orthosteric agonists. Compounds 6A and 7A did not elicit any G protein activation, cAMP inhibition or stimulation, or ERK 1/2 phosphorylation. Instead, a Schild analysis indicates a competitive, antagonistic interaction of compounds 6A and 7A with ACh in the Gɑi1 activation assay. Overexpression of the M2 mAChR may suggest an expression-dependent activation profile of compounds 6A and 7A. These data confirm that the M2 mAChR preferentially couples to Gɑi/o and to a lesser extent to Gɑs in response to canonical orthosteric ligands. However, this study was not able to detect Gɑi bias of compounds 6A and 7A, highlighting the importance of cellular background when classifying new ligands. This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.

Abstract A028: ZEB1 confers sensitivity to ferroptosis through regulation of iron metabolism

Abstract Introduction: Epithelial to Mesenchymal Transition (EMT) is a cellular phenotype which may contribute to metastasis and therapeutic resistance in cancer. Therefore, therapeutic targeting of EMT-like phenotypes in cancer cells may afford an approach to treating metastatic disease and/or thwarting therapeutic resistance. Recently, GPX4 inhibitors (GPX4i) became of interest in this field as they were identified as potent and selective compounds for cells in a mesenchymal state through induction of lipid peroxidation induced cell death also known as ferroptosis. The sensitivity to these inhibitors was also shown to be dependent on the master EMT regulator, ZEB1. However, the link between ZEB1 expression and ferroptosis susceptibility remains unclear. Methodology: We used PC-3E and TEM 4-18 cell lines, originally isolated from the PC3 prostate cancer cell line based on their differential ability to invade an endothelial monolayer, as our models of epithelial and EMT-like phenotypes respectively. To better understand the role of ZEB1 in ferroptosis susceptibility, we used ZEB1 KO TEM 4-18 cells as well as a panel of cancer cell lines that cover a broad spectrum of epithelial and EMT-like phenotypes. After evaluating the sensitivity to GPX4i in these cell lines, we examined different parameters affecting the lipid peroxidation pathway. We particularly focused on the regulation of iron metabolism by ZEB1. Results: The three GPX4i tested (ML210, ML162 and RSL3) displayed a greater toxicity against TEM 4-18 cells. Inhibitors of ferroptosis (ferrostatin-1, liproxstatin-1) completely reversed the effect of GPX4i indicating that ferroptosis was indeed triggered by GPX4i and responsible for their toxicity. Sensitivity to GPX4i correlated with ZEB1 expression in our panel of cancer cell lines and ZEB1 KO reversed toxicity of GPX4i in TEM 4-18 cells. Sensitivity to GPX4i correlated with a slightly higher labile iron pool in ZEB1 expressing cells. Expression of proteins with a previously established connection to iron metabolism such as Ferritin Light Chain (FtL), Ferritin Heavy Chain (FtH), Transferrin Receptor (TfR) and Prominin-2 (PROM2) were also dysregulated between resistant and sensitive cells. In particular, the ratio FtH:FtL and expression of PROM2 was positively correlated with resistance to GPX4i. In addition, using the Cancer Cell Line Encyclopedia (CCLE) database, we found that ZEB1 expression negatively correlated with PROM2 and Iron Responsive Element Binding Protein-2 (IREB2) suggesting these genes could be transcriptional targets of ZEB1. Conclusions: We validated GPX4i as potent EMT selective cytotoxic compounds and confirmed that the sensitivity to these inhibitors depends on ZEB1 expression. However, the mechanisms leading to sensitivity to GPX4i and how they connect to the EMT program have yet to be identified. As these mechanisms might be diverse, we hypothesize that ZEB1 regulates iron metabolism which is critical for ferroptosis induction. Citation Format: Marion Vanneste, Michael Darrin Henry, Akansha Jain. ZEB1 confers sensitivity to ferroptosis through regulation of iron metabolism [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr A028.

The effect of side chain variations on quinazoline-pyrimidine G-quadruplex DNA ligands

G-quadruplex (G4) DNA structures are involved in central biological processes such as DNA replication and transcription. These DNA structures are enriched in promotor regions of oncogenes and are thus promising as novel gene silencing therapeutic targets that can be used to regulate expression of oncoproteins and in particular those that has proven hard to drug with conventional strategies. G4 DNA structures in general have a well-defined and hydrophobic binding area that also is very flat and featureless and there are ample examples of G4 ligands but their further progression towards drug development is limited. In this study, we use synthetic organic chemistry to equip a drug-like and low molecular weight central fragment with different side chains and evaluate how this affect the compound's selectivity and ability to bind and stabilize G4 DNA. Furthermore, we study the binding interactions of the compounds and connect the experimental observations with the compound's structural conformations and electrostatic potentials to understand the basis for the observed improvements. Finally, we evaluate the top candidates' ability to selectively reduce cancer cell growth in a 3D co-culture model of pancreatic cancer which show that this is a powerful approach to generate highly active and selective low molecular weight G4 ligands with a promising therapeutic window.

Mechanical Properties Enhancement of the Cement Mortar by Synthetic Zeolite Polymer Composites

The performance of cement mortar can be improved with additives based on waste by-products. Synthetic zeolite polymer composites (referred as SZPC) produced from the combination of solid waste ashes with a selective acrylic compound was used as a cement mortar additive. The effect of SZPC as an additive on hydration reaction of ordinary Portland cement (referred as OPC) at different amounts of SZPC, from 1-4% of OPC weight, as well as microstructure and mechanical behavior of the cement mortar are determined. The results from the hydration reaction rate test showed that the optimum amount of SZPC as the additive was 2% of OPC weight. Compressive strength and flexural strength of the cement mortar after 1, 7, 14 and 28 days of curing increased, with the largestincreases at the early stage. Additions of SZPC, synthesized by a waste by-product, improved mechanical behavior of cement mortars supporting sustainable development and the circular economy.

INFLUENCE OF BIOMASS PRETREATMENT ON SUBSEQUENT PYROLYSIS AND HYDRODEOXYGENATION IN BIO-BASED TRANSPORT FUELS AND CHEMICALS PRODUCTION: A CRITICAL REVIEW

The present article aims to review the influence of various biomass pretreatments on the production of bio-based transportation fuel and chemicals via pyrolysis and hydrodeoxygenation (HDO). The article includes the influence of different thermochemical pretreatments such as dry torrefaction (DT), wet torrefaction (WT), steam explosion treatment (SET), hot water extraction (HWE), acid treatment (ACT), and alkali treatment (AKT) on bio-oil yield and bio-oil properties. HDO primarily includes dehydration, hydrogenolysis, decarbonylation, and hydrogenation. HDO can be classified based on stages (single and two-stage HDO), reaction pressure (high and low), and hydrogen presence (ex situ and in situ). The recent developments, advantages, and drawbacks associated with different types of HDO processes have been included. The article includes recent studies on designing various catalysts based on HDO conversion of different bio-oil compositions or selective model compounds to targeted bio-based products. The various biomass pretreatments impact the concentration of certain families of organic compounds present in bio-oil. Hence, the present review article also includes recommendations of specific biomass pretreatments for various HDO catalysts designed for selective model compounds or different bio-oil compositions. Few praiseworthy techno-economic analysis (TEA) studies on the influence of different biomass pretreatments on the minimum selling price (MSP) of bio-based products obtained at various production stages have been discussed.