Potent Competitive Inhibitor Research Articles

A computational assay for identifying millet-derived compounds that antagonize the interaction between bisphenols and estrogen-related receptor gamma

The use of Bisphenol A (BPA) and its analogs in industries, as well as the products made from them, is becoming a significant concern for human health. Scientific studies have revealed that BPA functions as an endocrine disruptor. While some analogs of BPA (bisphenols) have been used for a longer time, it was later discovered that they are toxic, similar to BPA. Their widespread use ensures their presence in the environment, and thus, everyone is exposed to them. Scientific research has shown that BPA interacts with estrogen-related receptor gamma (ERRγ), affecting its normal function. ERRγ is involved in biological processes including energy metabolism and mitochondrial function. Therefore, continuous exposure to bisphenols increases the risk of various diseases. In our previous study, we observed that some analogs of BPA had a higher binding affinity to ERRγ compared to BPA itself and analyzed the amino acid residues involved in this interaction. We hypothesized that by antagonizing the interaction between bisphenols and ERRγ, we could neutralize their toxic effects. Taking into account the health benefits of millets and their toxin removal properties, virtual screening of millet-derived compounds was conducted along with prediction of their ADMET profiles. Top five candidates were prioritized for Density Functional Theory (DFT) calculations and further analyses. Long-term molecular dynamics simulation (1 µs) were utilized to evaluate their binding, stability, and antagonizing abilities. Furthermore, reevaluation of their binding energy was conducted using the MM-PBSA method. This study reports millet-derived compounds, namely, Tricin 7-rutinoside, Tricin 7-glucoside, Glucotricin, Kaempferol, and Setarin. These compounds are predicted to be potent competitive inhibitors that can antagonize the interactions between bisphenols and ERRγ. These compounds could potentially assist in the development of future therapeutics. They may also be considered for use as food supplements, although further investigations, including wet-lab experiments and clinical studies, are needed.

In Silico Approach for Assessment of the Anti-tumor Potential of Cannabinoid Compounds by Targeting Glucose-6-Phosphate Dehydrogenase Enzyme.

Glucose-6-phosphate dehydrogenase (G6PD) is a pentose phosphate pathway (PPP) enzyme that generates NADPH, which is required for cellular redox equilibrium and reductive biosynthesis. It has been demonstrated that abnormal G6PD activation promotes cancer cell proliferation and metastasis. To date, no G6PD inhibitor has passed clinical testing successfully enough to be launched as a medicine. As a result, in this investigation, cannabinoids were chosen to evaluate their anticancer potential by targeting G6PD. Molecular docking indicated that three molecules, Tetrahydrocannabinolic acid (THCA), Cannabichromenic acid (CBCA), and tetrahydrocannabivarin (THCV), have the highest binding affinities for G6PD of -8.61, -8.39, and 8.01 Kcal mol. ADMET analysis found that all of them were safe prospective drug candidates. Molecular dynamics (MD) simulation and MM-PBSA analysis confirm the structural compactness and lower conformational variation of protein-ligand complexes, thereby maintaining structural stability and rigidity. Thus, our in silico investigation exhibited all three cannabinoids as potential competitive inhibitors of G6PD.

Substrate recognition principles for the PP2A-B55 protein phosphatase.

The PP2A-B55 phosphatase regulates a plethora of signaling pathways throughout eukaryotes. How PP2A-B55 selects its substrates presents a severe knowledge gap. By integrating AlphaFold modeling with comprehensive high-resolution mutational scanning, we show that α helices in substrates bind B55 through an evolutionary conserved mechanism. Despite a large diversity in sequence and composition, these α helices share key amino acid determinants that engage discrete hydrophobic and electrostatic patches. Using deep learning protein design, we generate a specific and potent competitive peptide inhibitor of PP2A-B55 substrate interactions. With this inhibitor, we uncover that PP2A-B55 regulates the nuclear exosome targeting (NEXT) complex by binding to an α-helical recruitment module in the RNA binding protein 7 (RBM7), a component of the NEXT complex. Collectively, our findings provide a framework for the understanding and interrogation of PP2A-B55 function in health and disease.

Investigation of the anti-inflammatory, anti-pruritic, and analgesic effects of sophocarpine inhibiting TRP channels in a mouse model of inflammatory itch and pain

Ethnopharmacological relevanceSophocarpine is a bioactive compound extracted from the dried root of Sophorae Flavesentis Aiton, a plant that has been used for thousands of years for various conditions including skin itch and pain. Its antipruritic and analgesic effects are suggested in publications, while the molecular mechanisms underneath interacting with TRP channels are not understood. Aim of the studyWe investigated the anti-inflammatory, antipruritic, and analgesic effects of sophocarpine in a murine inflammatory itch and pain model to elucidate the underlying mechanisms. Materials and methodsWe evaluated sophocarpine's anti-pruritic and analgesic effects by monitoring mice's scratching and wiping behaviors, and the anti-inflammatory effect by measuring psoriasis area and severity index (PASI) score. The mRNA and protein expression of TRPA1/TRPV1 was analyzed by real-time quantitative polymerase chain reaction and western blotting. We further investigated the relationship between sophocarpine and TRPA1/TRPV1 in mice administered allyl-isothiocyanate (AITC) or capsaicin and by molecular docking. ResultsWe found that sophocarpine decreased scratching bouts, wipes, and the PASI score, reduced the TNF-α and IL-1β in the skin and TRPA1 and TRPV1 in the trigeminal ganglion. Pretreatment of sophocarpine decreased AITC-induced scratching bouts and wipes and capsaicin-induced wipes. We also found potential competitive bindings between sophocarpine and AITC/capsaicin to TRPA1/TRPV1. ConclusionsSophocarpine is a potential competitive inhibitor of TRPA1 and TRPV1 channels eliciting strong anti-inflammatory, anti-pruritic, and analgesic effects, suggesting its significant therapeutic potential in treating diseases with inflammatory itch and pain.

IDENTIFICATION OF ANTIBACTERIAL AGENTS AGAINST KLEBSIELLA PNEUMONIAE TARGETING THE CTX-M-15 PROTEIN USING INTEGRATED STRUCTURE MODEL-BASED VIRTUAL SCREENING METHODS

The spread of carbapenem-resistant Gram-negative bacteria, particularly those having the bla CTX-M-15 gene, has stimulated a global challenge for β-lactam antimicrobial effectiveness. This study aims to identify commercially available compounds that demonstrate strong antibacterial properties with high efficacy and low toxicity to combat the increasing problem of antibiotic resistance. Virtual screening and molecular docking techniques were employed to generate a pharmacophore model based on the molecular structure. Eleven potential compounds were selected based on their IC50 values. Subsequently, a molecular docking approach was employed to select the best three small molecules for further comprehensive investigation. Moreover, absorption, distribution, metabolism, and excretion (ADME) and toxicity analysis ensured that it can be used as a drug without the effect of health. Finally, molecular dynamic (MD) simulations and generalized Born model and solvent accessibility (MMGB/SA) were carried out to evaluate the stability of these compounds against the receptor. Three selected compounds, specifically ZINCCID (ZINC94211493, ZINC20528448, and ZINC04331046), have exhibited strong binding affinities of -8.4, -8.1, and -7.7 kcal/mol, respectively. This has been predicted as a potential competitive inhibitor targeting CTX-M-15. However, further assessment through experimental lab studies is required to evaluate the efficacy of these compounds. Initially, a structure-based model was constructed, and subsequently, molecular docking, MD simulation, ADMET analysis, and MMGB/SA were performed. Through the A-to-Z virtual screening process, the top three natural compounds were identified as potential lead molecules in the development of novel drugs targeting CTX-M-15 for combating Klebsiella infections. Keywords: Klebsiella; Structure-based; Molecular docking; Pharmacophore modeling; CTX-M-15 protein; ADMET; MMGB/SA, MD simulation.

Repurposing Duloxetine as a Potent Butyrylcholinesterase Inhibitor: Potential Cholinergic Enhancing Benefits for Elderly Individuals with Depression and Cognitive Impairment.

Despite the advent of new treatment strategies, cholinesterase inhibitors (ChEIs) are still the go-to treatment for dementia disorders. ChEIs act by inhibiting the main acetylcholine-degrading enzyme, acetylcholinesterase (AChE). Nonetheless, accumulating evidence indicates that the impact of inhibition of the sister enzyme, butyrylcholinesterase (BChE), could be even broader in older adults due to the multifaceted role of BChE in several biological functional pathways. Therefore, we employed an in silico modeling-based drug repurposing strategy to identify novel potent BChE inhibitors from the FDA drug database. This was followed by in vitro screening and ex vivo enzyme kinetic validation using human plasma samples as the source of BChE. The analysis revealed that the antidepressant drug, duloxetine, inhibited BChE with high selectivity in comparison to AChE. In contrast, two other antidepressants, namely, citalopram and escitalopram exhibited a weak to moderate activity. Ex vivo enzyme inhibition kinetic analyses indicated that duloxetine acted as a competitive inhibitor of BChE with an inhibition constant (K i) of 210 nM. This K i value is comparable with 100-400 nM concentration of duloxetine following normal dosages in humans, thereby indicating that duloxetine should be able to induce a pharmacologically and biologically relevant in vivo inhibition of BChE. Additionally, we performed the enzyme inhibition kinetic assessment in parallel for ethopropazine, a known potent selective BChE inhibitor, and physostigmine, a dual inhibitor of AChE and BChE. These analyses indicated that duloxetine should be considered a potent BChE inhibitor since its K i was comparable with ethopropazine (K i = 150 nM) but was 4 times smaller than that of physostigmine (K i = 840 nM). In conclusion, this study reports the discovery of duloxetine being a highly potent selective competitive BChE inhibitor. This, in turn, indicates that duloxetine could be the choice of antidepressive treatment in older adults with both depressive and dementia symptoms since it may offer additional clinically beneficial effects via this secondary mode of cholinergic enhancing action.

Discovering potential WRN inhibitors from natural product database through computational methods

Microsatellite instability (MSI) is a relatively common feature associated with multiple cancers, and Werner syndrome (WRN) ATP-dependent helicase has been recognized as a novel target for treating MSI cancers, such as colorectal cancer. A small-molecule inhibitor targeting WRN would be a promising strategy for treating colorectal cancer with high MSI expression. In this study, we employed a computer-assisted drug discovery strategy to screen over 30,000 natural product molecules. By using a combination of docking, ligand efficiency, Molecular Mechanics/Generalized Born Surface Area (MM/GBSA), and thermodynamic integration (TI) calculations, we identified MOL008980, MOL010740, MOL011832, T4743, TN1166, and TNP-002173 as potential WRN inhibitors. Subsequent molecular dynamics simulation revealed that these screened natural products possessed better binding dynamic characteristics than ATP substrate and were capable of inhibiting the dynamic process of WRN, making them potential strong ATP competitive inhibitors. In conclusion, our computational approach revealed potential WRN inhibitors from a natural product database, providing a theoretical basis for future research.

Application of eprinomectin-containing parasiticides at label doses causes neurological toxicosis in cats homozygous for ABCB11930_1931del TC.

The feline MDR1 mutation (ABCB11930_1931delTC) has been associated with neurological toxicosis after topical application of eprinomectin products labeled for feline use. Information was collected from veterinarians who submitted samples for ABCB11930_1931delTC genotyping. In most cases, the submission form indicated an adverse event involving eprinomectin, in other cases submitting veterinarians were contacted to determine whether the patient had experienced an adverse drug event involving eprinomectin. If so, additional information was obtained to determine whether the case met inclusion criteria. 14 cases were highly consistent with eprinomectin toxicosis. Eight cats were homozygous for ABCB11930_1931del TC (3 died; 5 recovered). Six cats were homozygous wildtype (2 died; 4 recovered). The observed ABCB11930_1931delTC frequency (57%) was higher than the expected frequency (≤1%) in the feline population (Fisher Exact test, p < 0.01). Among wildtype cats, four were concurrently treated with potential competitive inhibitors of P-glycoprotein. Results indicate that topical eprinomectin products, should be avoided in cats homozygous for ABCB11930_1931delTC. This is a serious, preventable adverse event occurring in an identifiable subpopulation treated with FDA-approved products in accordance with label directions. Acquired P-glycoprotein deficiency resulting from drug interactions may enhance susceptibility to eprinomectin-induced neurological toxicosis in any cat, regardless of ABCB1 genotype.

Design, Synthesis, and Biological Studies of Flavone-Based Esters and Acids as Potential P450 2A6 Inhibitors.

As a potential means for smoking cessation and consequently prevention of smoking-related diseases and mortality, in this study, our goal was to investigate the inhibition of nicotine metabolism by P450 2A6. Smoking is the main cause of many diseases and disabilities and harms nearly every organ of the body. As reported by the Centers for Disease Control and Prevention (CDC), more than 16 million Americans are living with diseases caused by smoking. On average, the life expectancy of a smoker is about 10 years less than a nonsmoker. Smoking cessation can substantially reduce the incidence of smoking-related diseases, including cancer. At least, 70 of the more than 7000 cigarette smoke components, including polycyclic aromatic hydrocarbons, N-nitrosamines, and aromatic amines, are known carcinogens. Nicotine is the compound responsible for the addictive and psychopharmacological effects of tobacco. Cytochrome P450 enzymes are responsible for the phase I metabolism of many tobacco components, including nicotine. Nicotine is mainly metabolized by cytochrome P450s 2A6 and 2A13 to cotinine. This metabolism decreases the amount of available nicotine in the bloodstream, leading to increased smoking behavior and thus exposure to tobacco toxicants and carcinogens. Here, we report the syntheses and P450 2A6 inhibitory activities of a number of new flavone-based esters and acids. Three of the flavone derivatives studied were found to be potent competitive inhibitors of the enzyme. Docking studies were used to determine the possible mechanisms of the activity of these inhibitors.

Impact of posaconazole and diltiazem on pharmacokinetics of encorafenib, a BRAF V600 kinase inhibitor for melanoma and colorectal cancer with BRAF mutations.

Encorafenib is a potent and selective ATP competitive inhibitor of BRAF V600-mutant kinase approved for patients with BRAF-mutant melanoma and colorectal cancer. Encorafenib is mainly metabolized by cytochrome P450 (CYP) 3A4 invitro and may be susceptible to drug-drug interactions when co-administered with CYP3A inhibitors or inducers. The primary objective was to assess the impact of the strong CYP3A inhibitor posaconazole (part 1) and the moderate CYP3A and P-gp inhibitor diltiazem (part 2) on encorafenib pharmacokinetics in healthy volunteers following a single 50-mg dose. A total of 32 participants were enrolled (16 each in parts 1 and 2). The area under the curve extrapolated to infinity (AUCinf ) and maximum plasma concentration (Cmax ) geometric mean for encorafenib increased by 183% and 68.4%, respectively, when co-administered with posaconazole. Apparent encorafenib clearance decreased from 26.0 to 9.2 L/h when coadministered with posaconazole, and plasma terminal half-life (t½ ) of encorafenib increased from 4.3 to 7.3 h. The AUCinf and Cmax geometric mean for encorafenib increased by 83.0% and 44.7%, respectively, when co-administered with diltiazem. Similarly, the apparent encorafenib clearance decreased from 29.0 to 16.0 L/h when co-administered with diltiazem, and plasma t½ of encorafenib increased from 6.6 to 7.9 h. There were no deaths, serious adverse events (AEs), or patient discontinuations due to AEs in parts 1 or 2. The most frequently reported treatment-related AEs were erythema (n = 14; 88%) and headache (n = 11; 69%) in part 1 and headache (n = 7; 44%) in part 2. The results of this study indicate that co-administration of encorafenib with strong or moderate CYP3A4 inhibitors should be avoided.

Screening a library of potential competitive inhibitors against bacterial threonyl-tRNA synthetase: DFT calculations

Due to the growing interest in directing aminoacyl-tRNA synthetases for antimicrobial therapies, evaluating the binding proficiency of potential inhibitors against this target holds significant importance. In this work, we proposed potential ligands that could properly bind to the crucial Zn(II) cofactor located in the active site of Threonyl-tRNA synthetases (ThrRS), potentially functioning as competitive inhibitors. Initially, detailed DFT quantum chemical study was conducted to examine the binding ability of threonine against unnatural amino acids to cofactor Zn(II). Then, the binding energy value for each suggested ligand has been determined and compared to the value determined for the native substrate, threonine. Our screening investigation showed that the native threonine should coordinate in a bidentate fashion to this Zn(II) which lead to the highest (binding energy) BE Thereby, the synthetic site of ThrRS rejects unnatural amino acids that cannot afford this type of coordination to Zn(II) ion which has been supported by our calculations. Moreover, based on their binding to the Zn(II) and the obtained BE values compared to the cognate threonine, many potent ligands have been suggested. Importantly, ligands with deprotonated warheads showed the highest binding ability amongst a list of potential hits. Further investigation on the selected ligands using molecular docking and QM/MM calculations confirmed our findings of the suggested ligands being able to bind efficiently in the active site of ThrRS. The suggested hits from this study should be valuable in paving routs for developing candidates as competitive inhibitors against the bacterial ThrRS. Communicated by Ramaswamy H. Sarma

Evaluation of in vitro antiviral activity of SARS-CoV-2 Mpro inhibitor pomotrelvir and cross-resistance to nirmatrelvir resistance substitutions.

The unprecedented scale of the COVID-19 pandemic and the rapid evolution of SARS-CoV-2 variants underscore the need for broadly active inhibitors with a high barrier to resistance. The coronavirus main protease (Mpro) is an essential cysteine protease required for viral polyprotein processing and is highly conserved across human coronaviruses. Pomotrelvir is a novel Mpro inhibitor that has recently completed a phase 2 clinical trial. In this report, we demonstrated that pomotrelvir is a potent competitive inhibitor of SARS-CoV-2 Mpro with high selectivity against human proteases. In the enzyme assay, pomotrelvir is also active against Mpro proteins derived from human coronaviruses CoV-229E, CoV-OC43, CoV-HKU1, CoV-NL63, MERS, and SARS-CoV. In cell-based SARS-CoV-2 replicon and SARS-CoV-2 infection assays, pomotrelvir has shown potent inhibitory activity and is broadly active against SARS-CoV-2 clinical isolates including Omicron variants. Many resistance substitutions of the Mpro inhibitor nirmatrelvir confer cross-resistance to pomotrelvir, consistent with the finding from our enzymatic analysis that pomotrelvir and nirmatrelvir compete for the same binding site. In a SARS-CoV-2 infection assay, pomotrelvir is additive when combined with remdesivir or molnupiravir, two nucleoside analogs targeting viral RNA synthesis. In conclusion, our results from the in vitro characterization of pomotrelvir antiviral activity support its further clinical development as an alternative COVID-19 therapeutic option.

A small molecule inhibitor of PTP1B and PTPN2 enhances T cell anti-tumor immunity

The inhibition of protein tyrosine phosphatases 1B (PTP1B) and N2 (PTPN2) has emerged as an exciting approach for bolstering T cell anti-tumor immunity. ABBV-CLS-484 is a PTP1B/PTPN2 inhibitor in clinical trials for solid tumors. Here we have explored the therapeutic potential of a related small-molecule-inhibitor, Compound-182. We demonstrate that Compound-182 is a highly potent and selective active site competitive inhibitor of PTP1B and PTPN2 that enhances T cell recruitment and activation and represses the growth of tumors in mice, without promoting overt immune-related toxicities. The enhanced anti-tumor immunity in immunogenic tumors can be ascribed to the inhibition of PTP1B/PTPN2 in T cells, whereas in cold tumors, Compound-182 elicited direct effects on both tumor cells and T cells. Importantly, treatment with Compound-182 rendered otherwise resistant tumors sensitive to α-PD-1 therapy. Our findings establish the potential for small molecule inhibitors of PTP1B and PTPN2 to enhance anti-tumor immunity and combat cancer.

Arginase inhibitory activities of guaiane sesquiterpenoids from Curcuma comosa rhizomes.

Arginases are bimanganese enzymes involved in many human illnesses, and thus are targets for disease treatments. The screening of traditional medicinal plants demonstrated that an ethanol extract of Curcuma comosa rhizomes showed significant human arginase I and II inhibitory activity, and further fractionation led to the isolation of three known guaiane sesquiterpenoids, alismoxide (1), 7α,10α-epoxyguaiane-4α,11-diol (2) and guaidiol (3). Tests of their inhibitory activities on human arginases I and II revealed that 1 exhibited selective and potent competitive inhibition for human arginase I (IC50 = 30.2μM), whereas the other compounds lacked inhibitory activities against human arginases. To the best of our knowledge, this is the first demonstration of human arginase I inhibitory activity by a sesquiterpenoid. Thus, 1 is a primary and specific inhibitory molecule against human arginase I.

Lipophilic modification of salirasib modulates the antiproliferative and antimigratory activity

Salirasib, or farnesylthiosalicylic acid (FTS), is a salicylic acid derivative with demonstrated antineoplastic activity. While designed as a competitor of the substrate S-farnesyl cysteine on Ras, it is a potent competitive inhibitor of isoprenylcysteine carboxymethyl transferase. In this study, the antiproliferative activity on six different solid tumor cell lines was evaluated with a series of lipophilic thioether modified salirasib analogues, including those with or without a 1,2,3-triazole linker. A combination of bioassay, cheminformatics, docking, and in silico ADME-Tox was also performed. SAR analysis that analogues with three or more isoprene units or a long aliphatic chain exhibited the most potent activity. Furthermore, three compounds display superior antiproliferative activity than salirasib and similar potency compared to control anticancer drugs across all tested solid tumor cell lines. In addition, the behavior of the collection on migration and invasion, a key process in tumor metastasis, was also studied. Three analogues with specific antimigratory activity were identified with differential structural features being interesting starting points on the development of new antimetastatic agents.The antiproliferative and antimigratory effects observed suggest that modifying the thiol aliphatic/prenyl substituents can modulate the activity.

Halogenated class of oximes as a new class of monoamine oxidase-B inhibitors for the treatment of Parkinson’s disease: Synthesis, biochemistry, and molecular dynamics study

Oximes are the promising structural scaffold for inhibiting monoamine oxidase (MAO)-B. Eight chalcone-based oxime derivatives were synthesized by microwave-assisted technique, and their ability to inhibit human MAO (hMAO) enzymes were tested. All compounds showed higher inhibitory activity of hMAO-B than hMAO-A. In the CHBO subseries, CHBO4 most potently inhibited hMAO-B with an IC50 value of 0.031 μM, followed by CHBO3 (IC50 = 0.075 μM). In the CHFO subseries, CHFO4 showed the highest inhibition of hMAO-B with an IC50 value of 0.147 μM. Compound CHBO4 had the highest selectivity index (SI) value of 1290.3. However, CHBO3 and CHFO4 showed relatively low SI values of 27.7 and 19.2, respectively. The -Br substituent in the CHBO subseries at the para-position in the B-ring showed higher hMAO-B inhibition than the -F substituent in the CHFO subseries. In both series, hMAO-B inhibition increased with the substituents at para-position in A-ring (-F > -Br > -Cl > -H in order). Compound CHBO4 (-F in A-ring and -Br in B-ring) was 12.6-times potent than the substituents-reversed compound CHFO3 (-Br in A-ring and -F in B-ring; IC50 = 0.391 μM). In the kinetic study, Ki values of CHBO4 and CHFO4 for hMAO-B were 0.010 ± 0.005 and 0.040 ± 0.007 μM, respectively, with competitive inhibitions. Reversibility experiments showed that CHBO4 and CHFO4 were reversible hMAO-B inhibitors. In the cytotoxicity test using the Vero cells by the MTT technique, CHBO4 had low toxicity with an IC50 value of 128.8 µg/mL. In H2O2-induced cells, CHBO4 significantly reduced cell damage by scavenging reactive oxygen species (ROS). Molecular docking and dynamics showed the stable binding mode of the lead molecule CHBO4 on the active site of hMAO-B. These results suggest that CHBO4 is a potent reversible, competitive, and selective hMAO-B inhibitor and can be used as a treatment agent for neurological disorders.

A phase I study of MEK inhibitor selumetinib in combination with azacitidine in patients with higher-risk chronic myeloid neoplasia.

TPS7084 Background: Myelodysplastic syndrome (MDS), Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), and MDS/MPN overlap syndromes present significant clinical challenges for patients deemed transplant ineligible, and who are relapsed or refractory to conventional therapies. RAS-pathway activating mutations in myeloid malignancies are associated with a proliferative phenotype and contribute to disease progression. Cooperation between RAS-dependent signaling and epigenetic dysregulation provides the basis for rationally designed combination studies. Selumetinib (AZD6244) is a potent, selective, orally bioavailable, and non-ATP competitive small molecule inhibitor of MEK1/2, downstream of RAS. Methods: This is an investigator-initiated, Phase I, open-label dose-escalation study of selumetinib in combination with azacitidine for patients with higher risk MDS, MDS/MPNs, and myelofibrosis. The trial will enroll patients with high-risk myeloid neoplasms that meet disease-specific criteria for MDS or MPNs and who require treatment. This phase I study follows a 3+3 dose-escalation design, with three planned dose levels across two different cohorts (A and B). The dose of azacitidine 75 mg/m2 will remain stable, with three planned selumetinib dose levels (50 mg, 75 mg, and 100mg, respectively) across the two cohorts. Azacitidine will be given on days 1-7 followed by selumetinib from days 7-21 of 28 day cycles. Cohort A includes subjects with MDS with relapsed/refractory disease requiring therapy and MDS/MPN overlap syndromes; Cohort B includes subjects with myelofibrosis refractory or intolerant to JAK inhibitor therapy or ineligible for ruxolitinib treatment given baseline cytopenias (thrombocytopenia &lt; 50,000/uL, anemia &lt; 9 g/dL, and/or red cell transfusion dependent). The trial has an enrollment goal of 18 to 24 subjects, and treatment will continue indefinitely if the patient continues to derive benefit. Dose escalation will proceed independently within both cohorts. Cohort A is nearing completion of enrollment and cohort B is actively enrolling. The primary objective is to determine the maximum tolerated dose of selumetinib in combination with azacitidine. Select secondary and exploratory objectives include describing the preliminary clinical response rates and observing relationships between the presence of RAS activating mutations, RAS pathway activation, and clinical response. Clinical trial information: NCT03326310 .

Valorization of Salmo salar Skin Waste for the Synthesis of Angiotensin Converting Enzyme-1 (ACE1) Inhibitory Peptides.

One of potential inhibitors which is widely used for the clinical treatment of COVID-19 in comorbid patients is Angiostensin Converting Enzyme-1 (ACE1) inhibitor. A safer peptide-based ACE1 inhibitor derived from salmon skin collagen, that is considered as the by-product of the fish processing industry have been investigated in this study. The inhibitory activity against ACE1 was examined using in vitro and in silico methods. In vitro analysis includes the extraction of acid-soluble collagen, characterization using FTIR, Raman, UV–Vis, XRD, cytotoxicity assay, and determination of inhibition against ACE1. In silico method visualizes binding affinity, molecular interaction, and inhibition type of intact collagen and active peptides derived from collagen against ACE1 using molecular docking. The results of FTIR spectra detected amide functional groups (A, B, I, II, III) and imine proline/hydroxyproline, while the results of Raman displayed peak absorption of amide I, amide III, proline/hydroxyproline ring, phenylalanine, and protein backbone. Furthermore, UV–Vis spectra showed typical collagen absorption at 230 nm and based on XRD data, the chain types in the samples were α-helix. ACE1 inhibition activity was obtained in a concentration-dependent manner where the highest was 82.83% and 85.84% at concentrations of 1000, and 2000 µg/mL, respectively, and showed very low cytotoxicity at the concentration less than 1000 µg/mL. In silico study showed an interaction between ACE1 and collagen outside the active site with the affinity of − 213.89 kcal/mol. Furthermore, the active peptides of collagen displayed greater affinity compared to lisinopril, namely HF (His-Phe), WYT (Trp-Tyr-Thr), and WF (Trp-Phe) of − 11.52; − 10.22; − 9.58 kcal/mol, respectively. The salmon skin-derived collagen demonstrated ACE1 inhibition activity with a non-competitive inhibition mechanism. In contrast, the active peptides were predicted as potent competitive inhibitors against ACE1. This study indicated that valorization of fish by-product can lead to the production of a promising bioactive compound to treat COVID-19 patient with diabetic comorbid.

Combining In Vitro and In Silico New Approach Methods to Investigate Type 3 Iodothyronine Deiodinase Chemical Inhibition Across Species.

New approach methodologies (NAMs) are being developed to reduce and replace vertebrate animal testing in support of ecotoxicology and risk assessment. The US Environmental Protection Agency's Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) bioinformatic tool was used to evaluate amino acid sequence conservation of the type 3 iodothyronine deiodinase (DIO3) enzyme across species to demonstrate NAM applications for understanding effects of chemical interactions with a specific protein target. Existing literature was used to identify critical amino acids for thyroid hormone binding and interaction with a reducing cofactor. The SeqAPASS tool identifies whether known critical amino acids involved in ligand binding are exact, partial, or not matches across species compared with a template species based on molecular weight and side chain classification. This evaluation guided the design of variant proteins representing critical amino acid substitutions found in various species. Site-directed mutagenesis of the wild-type (WT) human DIO3 gene sequence was used to create six variant proteins expressed in cell culture, which were then tested in vitro for chemical inhibition. Significant differences in in vitro median inhibitory concentration results were observed among variants for potential competitive inhibitors. A molecular model representing the WT human DIO3 was constructed using Molecular Operating Environment (MOE) software and mutated in silico to create the six variants. The MOE Site Finder tool identified the proposed catalytic and cofactor sites and potential alternative binding sites. Virtual docking did not provide affinity scores with sufficient resolution to rank the potency of the chemical inhibitors. Chemical characteristics, function and location of substituted amino acids, and complexities of the protein target are important considerations in developing NAMs to evaluate chemical susceptibility across species. Environ Toxicol Chem 2023;42:1032-1048. © 2023 University of Wisconsin-Madison. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Targeting Enterococcus faecalis HMG-CoA reductase with a non-statin inhibitor

HMG-CoA reductase (HMGR), a rate-limiting enzyme of the mevalonate pathway in Gram-positive pathogenic bacteria, is an attractive target for development of novel antibiotics. In this study, we report the crystal structures of HMGR from Enterococcus faecalis (efHMGR) in the apo and liganded forms, highlighting several unique features of this enzyme. Statins, which inhibit the human enzyme with nanomolar affinity, perform poorly against the bacterial HMGR homologs. We also report a potent competitive inhibitor (Chembridge2 ID 7828315 or compound 315) of the efHMGR enzyme identified by a high-throughput, in-vitro screening. The X-ray crystal structure of efHMGR in complex with 315 was determined to 1.27 Å resolution revealing that the inhibitor occupies the mevalonate-binding site and interacts with several key active site residues conserved among bacterial homologs. Importantly, 315 does not inhibit the human HMGR. Our identification of a selective, non-statin inhibitor of bacterial HMG-CoA reductases will be instrumental in lead optimization and development of novel antibacterial drug candidates.