scholarly journals Pharmacophore Model for SARS-CoV-2 3CLpro Small-Molecule Inhibitors and in Vitro Experimental Validation of Computationally Screened Inhibitors

2021 ◽  
Author(s):  
Enrico Glaab ◽  
Ganesh Babu Manoharan ◽  
Daniel Abankwa
Keyword(s):  
Small Molecule ◽  
Experimental Validation ◽  
Small Molecule Inhibitors ◽  
Pharmacophore Model

scholarly journals A pharmacophore model for SARS-CoV-2 3CLpro small molecule inhibitors and in vitro experimental validation of computationally screened inhibitors

2021 ◽  
Author(s):  
Enrico Glaab ◽  
Ganesh Babu Manoharan ◽  
Daniel Abankwa
Keyword(s):  
Machine Learning ◽  
Molecular Dynamics ◽  
Virtual Screening ◽  
Small Molecule ◽  
Drug Target ◽  
Experimental Validation ◽  
Small Molecule Inhibitors ◽  
Pharmacophore Model ◽  
Computational Screening

AbstractAmong the biomedical efforts in response to the current coronavirus (COVID-19) pandemic, pharmacological strategies to reduce viral load in patients with severe forms of the disease are being studied intensively. One of the main drug target proteins proposed so far is the SARS-CoV-2 viral protease 3CLpro (also called Mpro), an essential component for viral replication. Ongoing ligand- and receptor-based computational screening efforts would be facilitated by an improved understanding of the electrostatic, hydrophobic and steric features that characterize small molecule inhibitors binding stably to 3CLpro, as well as by an extended collection of known binders.Here, we present combined virtual screening, molecular dynamics simulation, machine learning and in vitro experimental validation analyses which have led to the identification of small molecule inhibitors of 3CLpro with micromolar activity, and to a pharmacophore model that describes functional chemical groups associated with the molecular recognition of ligands by the 3CLpro binding pocket. Experimentally validated inhibitors using a ligand activity assay include natural compounds with available prior knowledge on safety and bioavailability properties, such as the natural compound rottlerin (IC50 = 37 μM), and synthetic compounds previously not characterized (e.g. compound CID 46897844, IC50 = 31 μM). In combination with the developed pharmacophore model, these and other confirmed 3CLpro inhibitors may provide a basis for further similarity-based screening in independent compound databases and structural design optimization efforts, to identify 3CLpro ligands with improved potency and selectivity.Overall, this study suggests that the integration of virtual screening, molecular dynamics simulations and machine learning can facilitate 3CLpro-targeted small molecule screening investigations. Different receptor-, ligand- and machine learning-based screening strategies provided complementary information, helping to increase the number and diversity of identified active compounds. Finally, the resulting pharmacophore model and experimentally validated small molecule inhibitors for 3CLpro provide resources to support follow-up computational screening efforts for this drug target.

scholarly journals Targeting dysregulation signatures of p53-MDM2 interactions to identify newer small molecule inhibitors for cancer therapy: Insight from computational direction

2021 ◽  
Author(s):  
Prosper Obed Chukwuemeka ◽  
Haruna Isiyaku Umar ◽  
Opeyemi Iwaloye ◽  
Oluwaseyi Matthew Oretade ◽  
Christopher Busayo Olowosoke ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Therapeutic Option ◽  
Pharmacophore Model ◽  
In Vivo Studies ◽  
Hydrogen Bond Acceptor ◽  
Potential Inhibitors

Abstract Dysregulation of the p53-MDM2 interactions has been implicated in majority of human tumors presenting a target for finding small molecule inhibitors. In this study, a training set of 17 experimentally tested inhibitors of MDM2 was used to develop series of pharmacophore models among which a four-featured (AHRR_1) model with one hydrogen bond acceptor, one hydrophobic group and two aromatic ring features and characterized by a survival score of 4.176 was considered significant among the top ranked generated hypothesis. Further, the model was validated by an external set of actives and decoy molecules and was found to exhibit encouraging statistical attributes (such as AUC > 0.7, BEDROC > 0.5 and EF > 1.0 etc). The model was used to screen the ZINC compound database, from the database, the top best 1375 hits satisfying the pharmacophore model was were docked to MDM2 protein to identify the likely interactions of the compounds as well as their binding affinity with MDM2. Further, druglikeness and pharmacokinetic properties screening on top-ranked compounds with higher binding affinity than reference inhibitors revealed four compounds (ZINC02639178, ZINC38933175, ZINC77969611, and ZINC06752762) with suitable pharmacological properties including low ligand toxicity. Investigation of the dynamic behaviour of each candidate inhibitors in complex with MDM2 via molecular dynamic simulation suggested ZINC02639178 and ZINC06752762 as the most potential inhibitors. Thus, these compounds may emerged as therapeutic option for cancer treatment after extensive in vitro and in vivo studies.

EXTH-31. BRAIN DISTRIBUTION, CLEARANCE AND TOXICITY EVALUATION OF SMALL-MOLECULE INHIBITORS FOLLOWING CONVECTION-ENHANCED DELIVERY TO THE BRAINSTEM

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi170-vi170
Author(s):  
Erica Power ◽  
Juhee Oh ◽  
Jonghoon Choi ◽  
William Elmquist ◽  
David Daniels
Keyword(s):  
Small Molecule ◽  
Drug Concentration ◽  
Small Molecule Inhibitors ◽  
Efflux Pump ◽  
Sprague Dawley ◽  
Convection Enhanced Delivery ◽  
Efflux Pump Inhibitor ◽  
Delivery Technique ◽  
The Brain

Abstract BACKGROUND Diffuse midline gliomas (DMGs) harboring the H3K27M mutation are highly aggressive, fatal brainstem tumors that primarily occur in children. The blood-brain barrier (BBB) prevents numerous drugs from reaching CNS tumors, like DMG, at cytotoxic concentrations. Convection-enhanced delivery (CED) has emerged as a drug delivery technique that bypasses the BBB through a direct interstitial infusion under a pressure gradient. However, drug distribution and clearance from the brain following CED is poorly understood and has been cited as a potential reason for the lack of efficacy observed in prior clinical trials. OBJECTIVE The objective of this study was to understand how two small molecule inhibitors (alisertib, ponatinib) that inhibit cell growth and proliferation in DMG cells in vitro distribute and clear from the brain following CED to the brainstem. METHODS Sprague-dawley rats underwent a single 60mL CED infusion of drug to the brainstem (200mM alisertib, 10mM ponatinib) and were sacrificed 0.083, 1, 2, 4, 8 and 24 hours following the completion of the infusion. Brains were dissected and drug concentration was determined via HPLC analysis. RESULTS No rats showed any clinical or neurological signs of toxicity post-infusion. Both drugs showed significant differences in drug concentration based on anatomical brain region where higher concentrations were observed in the pons and cerebellum compared to the cortex. Drug half-life in the brain was ~0.5 hours for alisertib and ~1 hour for ponatinib, but this was not significantly increased following co-administration of elacridar, a BBB efflux pump inhibitor. CONCLUSIONS These results suggest that elimination of drugs from the brain in a complex, multifactorial mechanism that warrants further preclinical investigation prior to the initiation of a clinical trial.

Synthesis and in vitro evaluation of novel small molecule inhibitors of bacterial arylamine N-acetyltransferases (NATs)

2003 ◽  
Vol 13 (15) ◽  
pp. 2527-2530 ◽  
Author(s):  
Edward W. Brooke ◽  
Stephen G. Davies ◽  
Andrew W. Mulvaney ◽  
Minoru Okada ◽  
Frédérique Pompeo ◽  
...  
Keyword(s):  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
In Vitro Evaluation

scholarly journals High Throughput in Silico Identification of Novel Phytochemical Inhibitors for the Master Regulator of Inflammation (TNFα)

2021 ◽  
Author(s):  
Pratap Kumar Parida ◽  
Dipak Paul ◽  
Debamitra Chakravorty
Keyword(s):  
Small Molecule ◽  
High Throughput ◽  
In Silico ◽  
Small Molecule Inhibitors ◽  
Binding Free Energy ◽  
Natural Compounds ◽  
Free Energy Calculations ◽  
Compound Libraries ◽  
Relative Binding

<p><a>The over expression of Tumor necrosis factor-α (TNFα) has been implicated in a variety of disease and is classified as a therapeutic target for inflammatory diseases (Crohn disease, psoriasis, psoriatic arthritis, rheumatoid arthritis).Commercially available therapeutics are biologics which are associated with several risks and limitations. Small molecule inhibitors and natural compounds (saponins) were identified by researchers as lead molecules against TNFα, however, </a>they were often associated with high IC50 values which can lead to their failure in clinical trials. This warrants research related to identification of better small molecule inhibitors by screening of large compound libraries. Recent developments have demonstrated power of natural compounds as safe therapeutics, hence, in this work, we have identified TNFα phytochemical inhibitors using high throughput <i>in silico </i>screening approaches of 6000 phytochemicals followed by 200 ns molecular dynamics simulations and relative binding free energy calculations. The work yielded potent hits that bind to TNFα at its dimer interface. The mechanism targeted was inhibition of oligomerization of TNFα upon phytochemical binding to restrict its interaction with TNF-R1 receptor. MD simulation analysis resulted in identification of two phytochemicals that showed stable protein-ligand conformations over time. The two compounds were triterpenoids: Momordicilin and Nimbolin A with relative binding energy- calculated by MM/PBSA to be -190.5 kJ/Mol and -188.03 kJ/Mol respectively. Therefore, through this work it is being suggested that these phytochemicals can be used for further <i>in vitro</i> analysis to confirm their inhibitory action against TNFα or can be used as scaffolds to arrive at better drug candidates.</p>

Abstract 523: Factor XIIa: New Insights on Chemical Tractability and Target Indications From a Potent and Selective Tool Inhibitor

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Christopher M Barbieri ◽  
Xinkang Wang ◽  
Xueping Zhou ◽  
Aimie M Ogawa ◽  
Kim O'Neil ◽  
...  
Keyword(s):  
Small Molecule ◽  
Active Site ◽  
Small Molecule Inhibitors ◽  
Plaque Rupture ◽  
Rabbit Model ◽  
Human Albumin ◽  
Stroke Treatment ◽  
Safe Strategy ◽  
Rupture Model

FXII is an emerging target for thrombosis, yet several questions remain to be addressed. Firstly, from drug discovery perspective, level of enzyme occupancy needed for efficacy (which largely dictates potency and selectivity requirement for small molecule inhibitors) is unclear, as most reported active site inhibitors have some level of off-target activities. Secondly, from disease treatment perspective, it is unclear whether FXIIa inhibition will be a safe strategy for stroke treatment or prevention, as it was recently reported that FXIIa inhibition destabilized the subocclusive thrombi in a plaque rupture model. In this presentation, we set out to address these questions using a previously described molecule, Inf4mut15. We generated the human albumin (HA)-Inf4mut15 fusion protein (Mut-inf) for our studies. In vitro Mut-inf displayed comparable potency as the widely used wild-type HA-Infestin4 (WT-inf) (human FXIIa Ki = 73 and 120 pM, respectively). Both infs acted as competitive reversible active site inhibitors of FXIIa, with no binding to FXII zymogen, hence same mode of action as certain small molecule inhibitors. Mut-inf, however, was much more selective against plasmin compared to WT-inf (20,000- and 75-fold Ki separation, respectively), consistent with results from the functional tPA-induced TEG assay, where Ly60 was reduced dose-dependently by WT- but not Mut-inf. Mut-inf aPTT doubling concentration was 15 uM and FXIIa Ki in 30% plasma was 3.5 nM. Calculated enzyme occupancy for Mut-inf for doubling human aPTT is thus 99.9%. In the rabbit model of cerebral microembolic signals (MES) induced by FeCl 3 injury of the carotid artery, treatment with vehicle (n=7), WT-, and Mut-inf (1mg/kg and n=5 each) produced arterial thrombus of 6.0±0.4, 1.9±0.6, and 0.2±0.1 mg, respectively; incidence of MES detected in the middle cerebral artery was 4.1±1.3, 1.8±0.6, and 0.0±0.0, respectively. In summary, our studies demonstrated that very high enzyme occupancy will be required for achieving a putative aPTT doubling target in human for FXIIa active site inhibitors, highlighting the challenge with the small molecule modality. Our MES studies suggest that targeting FXII may offer a safe strategy for stroke prevention and/or other thromboembolic disorders.

scholarly journals Novel Small-Molecule Inhibitors of RNA Polymerase III

2003 ◽  
Vol 2 (2) ◽  
pp. 256-264 ◽  
Author(s):  
Liping Wu ◽  
Jing Pan ◽  
Vala Thoroddsen ◽  
Deborah R. Wysong ◽  
Ronald K. Blackman ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase ◽  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Rna Polymerase Iii ◽  
Wild Type ◽  
Biochemical Assays ◽  
Transcription In Vitro ◽  
Pol Iii

ABSTRACT A genetic approach utilizing the yeast Saccharomyces cerevisiae was used to identify the target of antifungal compounds. This analysis led to the identification of small molecule inhibitors of RNA polymerase (Pol) III from Saccharomyces cerevisiae. Three lines of evidence show that UK-118005 inhibits cell growth by targeting RNA Pol III in yeast. First, a dominant mutation in the g domain of Rpo31p, the largest subunit of RNA Pol III, confers resistance to the compound. Second, UK-118005 rapidly inhibits tRNA synthesis in wild-type cells but not in UK-118005 resistant mutants. Third, in biochemical assays, UK-118005 inhibits tRNA gene transcription in vitro by the wild-type but not the mutant Pol III enzyme. By testing analogs of UK-118005 in a template-specific RNA Pol III transcription assay, an inhibitor with significantly higher potency, ML-60218, was identified. Further examination showed that both compounds are broad-spectrum inhibitors, displaying activity against RNA Pol III transcription systems derived from Candida albicans and human cells. The identification of these inhibitors demonstrates that RNA Pol III can be targeted by small synthetic molecules.

scholarly journals Identification of potential TNF-α inhibitors: from in silico to in vitro studies

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Komal Zia ◽  
Sajda Ashraf ◽  
Almas Jabeen ◽  
Maria Saeed ◽  
Mohammad Nur-e-Alam ◽  
...  
Keyword(s):  
Small Molecule ◽  
Therapeutic Potential ◽  
Pharmacophore Model ◽  
Docking Studies ◽  
Immune Functions ◽  
Binding Interaction ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Potential Inhibitors

AbstractTumor Necrosis Factor Alpha (TNF-α) is a pleiotropic pro-inflammatory cytokine. It act as central biological regulator in critical immune functions, but its dysregulation has been linked with a number of diseases. Inhibition of TNF-α has considerable therapeutic potential for diseases such as cancer, diabetes, and especially autoimmune diseases. Despite the fact that many small molecule inhibitors have been identified against TNF-α, no orally active drug has been reported yet which demand an urgent need of a small molecule drug against TNF-α. This study focuses on the development of ligand-based selective pharmacophore model to perform virtual screening of plant origin natural product database for the identification of potential inhibitors against TNF-α. The resultant hits, identified as actives were evaluated by molecular docking studies to get insight into their potential binding interaction with the target protein. Based on pharmacophore matching, interacting residues, docking score, more affinity towards TNF-α with diverse scaffolds five compounds were selected for in vitro activity study. Experimental validation led to the identification of three chemically diverse potential compounds with the IC50 32.5 ± 4.5 µM, 6.5 ± 0.8 µM and 27.4 ± 1.7 µM, respectively.

scholarly journals Small-Molecule Inhibitors of Staphylococcus aureus RnpA-Mediated RNA Turnover and tRNA Processing

2015 ◽  
Vol 59 (4) ◽  
pp. 2016-2028 ◽  
Author(s):  
Tess M. Eidem ◽  
Nicole Lounsbury ◽  
John F. Emery ◽  
Jeffrey Bulger ◽  
Andrew Smith ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Antimicrobial Activities ◽  
Rna Degradation ◽  
Dual Function ◽  
Content Type ◽  
Trna Processing ◽  
Cellular Assays

ABSTRACTNew agents are urgently needed for the therapeutic treatment ofStaphylococcus aureusinfections. In that regard,S. aureusRNase RnpA may represent a promising novel dual-function antimicrobial target that participates in two essential cellular processes, RNA degradation and tRNA maturation. Accordingly, we previously used a high-throughput screen to identify small-molecule inhibitors of the RNA-degrading activity of the enzyme and showed that the RnpA inhibitor RNPA1000 is an attractive antimicrobial development candidate. In this study, we used a series ofin vitroand cellular assays to characterize a second RnpA inhibitor, RNPA2000, which was identified in our initial screening campaign and is structurally distinct from RNPA1000. In doing so, it was found thatS. aureusRnpA does indeed participate in 5′-precursor tRNA processing, as was previously hypothesized. Further, we show that RNPA2000 is a bactericidal agent that inhibits both RnpA-associated RNA degradation and tRNA maturation activities bothin vitroand withinS. aureus. The compound appears to display specificity for RnpA, as it did not significantly affect thein vitroactivities of unrelated bacterial or eukaryotic ribonucleases and did not display measurable human cytotoxicity. Finally, we show that RNPA2000 exhibits antimicrobial activity and inhibits tRNA processing in efflux-deficient Gram-negative pathogens. Taken together, these data support the targeting of RnpA for antimicrobial development purposes, establish that small-molecule inhibitors of both of the functions of the enzyme can be identified, and lend evidence that RnpA inhibitors may have broad-spectrum antimicrobial activities.

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