7 results on '"Tommy Szeto"'
Search Results
2. Discovery of SARS-CoV‑2 Papain-like Protease Inhibitors through a Combination of High-Throughput Screening and a FlipGFP-Based Reporter Assay
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Julia Alma Townsend, George Lambrinidis, Michael T. Marty, Yu Chen, Chunlong Ma, Maura V Gongora, Antonios Kolocouris, Jun Wang, Fushun Zhang, Yan Xiang, Zilei Xia, Xiujun Zhang, Xiangzhi Meng, Mandy Ba, Tommy Szeto, Michael Dominic Sacco, and Yanmei Hu
- Subjects
Conformational change ,medicine.drug_class ,General Chemical Engineering ,High-throughput screening ,medicine.medical_treatment ,Cell ,papain-like protease ,Article ,chemistry.chemical_compound ,medicine ,QD1-999 ,chemistry.chemical_classification ,Reporter gene ,Protease ,SARS-CoV-2 ,Chemistry ,COVID-19 ,General Chemistry ,antiviral ,PLpro ,Papain ,medicine.anatomical_structure ,Förster resonance energy transfer ,Enzyme ,Biochemistry ,FlipGFP ,Antiviral drug ,Research Article - Abstract
The papain-like protease (PLpro) of SARS-CoV-2 is a validated antiviral drug target. Through a fluorescence resonance energy transfer-based high-throughput screening and subsequent lead optimization, we identified several PLpro inhibitors including Jun9-72-2 and Jun9-75-4 with improved enzymatic inhibition and antiviral activity compared to GRL0617, which was reported as a SARS-CoV PLpro inhibitor. Significantly, we developed a cell-based FlipGFP assay that can be applied to predict the cellular antiviral activity of PLpro inhibitors in the BSL-2 setting. X-ray crystal structure of PLpro in complex with GRL0617 showed that binding of GRL0617 to SARS-CoV-2 induced a conformational change in the BL2 loop to a more closed conformation. Molecular dynamics simulations showed that Jun9-72-2 and Jun9-75-4 engaged in more extensive interactions than GRL0617. Overall, the PLpro inhibitors identified in this study represent promising candidates for further development as SARS-CoV-2 antivirals, and the FlipGFP-PLpro assay is a suitable surrogate for screening PLpro inhibitors in the BSL-2 setting., A cell-based FlipGFP reporter assay was developed for the screening of SARS-CoV-2 papain-like protease inhibitors and was shown to have a positive correlation with antiviral activity.
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- 2021
3. Expedited Approach toward the Rational Design of Noncovalent SARS-CoV-2 Main Protease Inhibitors
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Jun Wang, Chunlong Ma, Xiujun Zhang, Yanmei Hu, David C. Schultz, Michael Dominic Sacco, Naoya Kitamura, Xiangzhi Meng, Adis Kukuljac, Mandy Ba, Tommy Szeto, Julia Alma Townsend, Michael T. Marty, Fushun Zhang, Yu Chen, Yan Xiang, and Sara Cherry
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Models, Molecular ,Proteases ,Pyrrolidines ,Proline ,Stereochemistry ,medicine.drug_class ,medicine.medical_treatment ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Microbial Sensitivity Tests ,Cysteine Proteinase Inhibitors ,Antiviral Agents ,01 natural sciences ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Boceprevir ,Chlorocebus aethiops ,Drug Discovery ,medicine ,Animals ,Humans ,Binding site ,Vero Cells ,Coronavirus 3C Proteases ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Protease ,Dose-Response Relationship, Drug ,Molecular Structure ,SARS-CoV-2 ,Rational design ,COVID-19 ,COVID-19 Drug Treatment ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,Enzyme ,chemistry ,Drug Design ,Molecular Medicine ,Sulfonic Acids ,Antiviral drug - Abstract
The main protease (M(pro)) of SARS-CoV-2 is a validated antiviral drug target. Several M(pro) inhibitors have been reported with potent enzymatic inhibition and cellular antiviral activity, including GC376, boceprevir, calpain inhibitors II and XII, each containing a reactive warhead that covalently modifies the catalytic Cys145. Coupling structure-based drug design with the one-pot Ugi four-component reaction, we discovered one of the most potent non-covalent inhibitors 23R (Jun8-76-3A) that is structurally distinct from the canonical M(pro) inhibitor GC376. Significantly, 23R is highly selective compared with covalent inhibitors such as GC376, especially towards host proteases. The co-crystal structure of SARS-CoV-2 M(pro) with 23R revealed a previously unexplored binding site located in between the S2 and S4 pockets. Overall, this study discovered 23R, one of the most potent and selective non-covalent SARS-CoV-2 M(pro) inhibitors reported to date, and a novel binding pocket in M(pro) that can be explored for inhibitor design.
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- 2021
4. Rational Design of Hybrid SARS-CoV-2 Main Protease Inhibitors Guided by the Superimposed Cocrystal Structures with the Peptidomimetic Inhibitors GC-376, Telaprevir, and Boceprevir
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Tommy Szeto, Michael Dominic Sacco, Xiangzhi Meng, Yu Chen, Yanmei Hu, Jun Wang, Fushun Zhang, Yan Xiang, Chunlong Ma, and Zilei Xia
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Proteases ,Peptidomimetic ,medicine.drug_class ,medicine.medical_treatment ,viruses ,Article ,Telaprevir ,Cathepsin L ,3CL protease ,medicine ,Pharmacology (medical) ,Pharmacology ,Protease ,biology ,Chemistry ,SARS-CoV-2 ,Rational design ,virus diseases ,COVID-19 ,Cysteine protease ,antiviral ,Biochemistry ,main protease ,biology.protein ,Antiviral drug ,medicine.drug - Abstract
SARS-CoV-2 main protease (Mpro) is a cysteine protease that mediates the cleavage of viral polyproteins and is a validated antiviral drug target. Mpro is highly conserved among all seven human coronaviruses, with certain Mpro inhibitors having broad-spectrum antiviral activity. In this study, we designed two hybrid inhibitors UAWJ9-36-1 and UAWJ9-36-3 based on the superimposed X-ray crystal structures of SARS-CoV-2 Mpro with GC-376, telaprevir, and boceprevir. Both UAWJ9-36-1 and UAWJ9-36-3 showed potent binding and enzymatic inhibition against the Mpro's from SARS-CoV-2, SARS-CoV, MERS-CoV, HCoV-OC43, HCoV-NL63, HCoV-229E, and HCoV-HKU1. Cell-based Flip-GFP Mpro assay results show that UAWJ9-36-1 and UAWJ9-36-3 inhibited the intracellular protease activity of SARS-CoV-2 Mpro. In addition, UAWJ9-36-1 and UAWJ9-36-3 had potent antiviral activity against SARS-CoV-2, HCoV-OC43, HCoV-NL63, and HCoV-229E, with UAWJ9-36-3 being more potent than GC-376 in inhibiting SARS-CoV-2. Selectivity profiling revealed that UAWJ9-36-1 and UAWJ9-36-3 had an improved selectivity index over that of GC-376 against host cysteine proteases calpain I and cathepsin L, but not cathepsin K. The X-ray crystal structures of SARS-CoV-2 Mpro with UAWJ9-36-1 and UAWJ9-36-3 were both solved at 1.9 A, which validated our design hypothesis. Overall, hybrid inhibitors UAWJ9-36-1 and UAWJ9-36-3 are promising candidates to be further developed as broad-spectrum coronavirus antivirals.
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- 2021
5. Boceprevir, Calpain Inhibitors II and XII, and GC-376 Have Broad-Spectrum Antiviral Activity against Coronaviruses
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Bart Tarbet, Chunlong Ma, Brett L. Hurst, Jun Wang, Yanmei Hu, and Tommy Szeto
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0301 basic medicine ,medicine.medical_treatment ,viruses ,Cathepsin L ,Carbonates ,Coronavirus OC43, Human ,chemistry.chemical_compound ,Coronavirus 229E, Human ,Chlorocebus aethiops ,boceprevir ,Coronavirus 3C Proteases ,chemistry.chemical_classification ,Alanine ,biology ,Serine Endopeptidases ,virus diseases ,Drug Combinations ,Infectious Diseases ,Middle East Respiratory Syndrome Coronavirus ,medicine.symptom ,Oligopeptides ,Proline ,030106 microbiology ,Antiviral Agents ,Article ,Cell Line ,03 medical and health sciences ,Leucine ,Boceprevir ,medicine ,Animals ,Humans ,Vero Cells ,Glycoproteins ,Protease ,SARS-CoV-2 ,HEK 293 cells ,COVID-19 ,Virology ,Adenosine Monophosphate ,GC-376 ,respiratory tract diseases ,COVID-19 Drug Treatment ,Coronavirus NL63, Human ,030104 developmental biology ,Enzyme ,HEK293 Cells ,chemistry ,Mechanism of action ,Cell culture ,main protease ,calpain inhibitor ,Vero cell ,biology.protein ,Caco-2 Cells ,Sulfonic Acids - Abstract
As the COVID-19 pandemic continues to fold out, the morbidity and mortality are increasing daily. Effective treatment for SARS-CoV-2 is urgently needed. We recently discovered four SARS-CoV-2 main protease (Mpro) inhibitors including boceprevir, calpain inhibitors II and XII and GC-376 with potent antiviral activity against infectious SARS-CoV-2 in cell culture. Despite the weaker enzymatic inhibition of calpain inhibitors II and XII against Mpro compared to GC-376, calpain inhibitors II and XII had more potent cellular antiviral activity. This observation promoted us to hypothesize that the cellular antiviral activity of calpain inhibitors II and XII might also involve the inhibition of cathepsin L in addition to Mpro. To test this hypothesis, we tested calpain inhibitors II and XII in the SARS-CoV-2 pseudovirus neutralization assay in Vero E6 cells and found that both compounds significantly decreased pseudoviral particle entry into cells, indicating their role in inhibiting cathepsin L. The involvement of cathepsin L was further confirmed in the drug time-of-addition experiment. In addition, we found that these four compounds not only inhibit SARS-CoV-2, but also SARS-CoV, MERS-CoV, as well as human coronaviruses (CoVs) 229E, OC43, and NL63. The mechanism of action is through targeting the viral Mpro, which was supported by the thermal shift binding assay and enzymatic FRET assay. We further showed that these four compounds have additive antiviral effect when combined with remdesivir. Altogether, these results suggest that boceprevir, calpain inhibitors II and XII, and GC-376 are not only promising antiviral drug candidates against existing human coronaviruses, but also might work against future emerging CoVs., Graphical Abstract
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- 2021
6. Boceprevir, calpain inhibitors II and XII, and GC-376 have broad-spectrum antiviral activity against coronaviruses in cell culture
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Bart Tarbet, Chunlong Ma, Jun Wang, Yanmei Hu, Tommy Szeto, and Brett L. Hurst
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medicine.drug_class ,medicine.medical_treatment ,viruses ,Pharmacology ,Article ,Cathepsin L ,chemistry.chemical_compound ,Boceprevir ,medicine ,boceprevir ,chemistry.chemical_classification ,Cathepsin ,Protease ,biology ,Chemistry ,SARS-CoV-2 ,virus diseases ,COVID-19 ,GC-376 ,respiratory tract diseases ,Enzyme ,Mechanism of action ,main protease ,calpain inhibitor ,Vero cell ,biology.protein ,Antiviral drug ,medicine.symptom - Abstract
As the COVID-19 pandemic continues to fold out, the morbidity and mortality are increasing daily. Effective treatment for SARS-CoV-2 is urgently needed. We recently discovered four SARS-CoV-2 main protease (Mpro) inhibitors including boceprevir, calpain inhibitors II and XII and GC-376 with potent antiviral activity against infectious SARS-CoV-2 in cell culture. Despite the weaker enzymatic inhibition of calpain inhibitors II and XII against Mprocompared to GC-376, calpain inhibitors II and XII had more potent cellular antiviral activity. This observation promoted us to hypothesize that the cellular antiviral activity of calpain inhibitors II and XII might also involve the inhibition of cathepsin L in addition to Mpro. To test this hypothesis, we tested calpain inhibitors II and XII in the SARS-CoV-2 pseudovirus neutralization assay in Vero E6 cells and found that both compounds significantly decreased pseudoviral particle entry into cells, indicating their role in inhibiting cathepsin L. The involvement of cathepsin L was further confirmed in the drug time-of-addition experiment. In addition, we found that these four compounds not only inhibit SARS-CoV-2, but also SARS-CoV, MERS-CoV, as well as human coronaviruses (CoVs) 229E, OC43, and NL63. The mechanism of action is through targeting the viral Mpro, which was supported by the thermal shift binding assay and enzymatic FRET assay. We further showed that these four compounds have additive antiviral effect when combined with remdesivir. Altogether, these results suggest that boceprevir, calpain inhibitors II and XII, and GC-376 are not only promising antiviral drug candidates against existing human coronaviruses, but also might work against future emerging CoVs.
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- 2020
7. Boceprevir, GC-376, and calpain inhibitors II, XII inhibit SARS-CoV-2 viral replication by targeting the viral main protease
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Tommy Szeto, Michael Dominic Sacco, Michael T. Marty, Jun Wang, Xiujun Zhang, Yanmei Hu, Julia Alma Townsend, Brett L. Hurst, Bart Tarbet, Chunlong Ma, and Yu Chen
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Peptidomimetic ,Viral protein ,medicine.medical_treatment ,Biology ,calpain inhibitors ,medicine.disease_cause ,Virus ,Article ,3CL protease ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Boceprevir ,medicine ,boceprevir ,Humans ,Molecular Biology ,030304 developmental biology ,Coronavirus ,chemistry.chemical_classification ,0303 health sciences ,Protease ,SARS-CoV-2 ,COVID-19 ,Cell Biology ,Virology ,GC-376 ,High-Throughput Screening Assays ,Förster resonance energy transfer ,Enzyme ,Pharmaceutical Preparations ,Mechanism of action ,chemistry ,Viral replication ,main protease ,medicine.symptom ,Structural biology ,030217 neurology & neurosurgery ,Peptide Hydrolases - Abstract
A novel coronavirus SARS-CoV-2, also called novel coronavirus 2019 (nCoV-19), started to circulate among humans around December 2019, and it is now widespread as a global pandemic. The disease caused by SARS-CoV-2 virus is called COVID-19, which is highly contagious and has an overall mortality rate of 6.96% as of May 4, 2020. There is no vaccine or antiviral available for SARS-CoV-2. In this study, we report our discovery of inhibitors targeting the SARS-CoV-2 main protease (Mpro). Using the FRET-based enzymatic assay, several inhibitors including boceprevir, GC-376, and calpain inhibitors II, and XII were identified to have potent activity with single-digit to submicromolar IC50 values in the enzymatic assay. The mechanism of action of the hits was further characterized using enzyme kinetic studies, thermal shift binding assays, and native mass spectrometry. Significantly, four compounds (boceprevir, GC-376, calpain inhibitors II and XII) inhibit SARS-CoV-2 viral replication in cell culture with EC50 values ranging from 0.49 to 3.37 μM. Notably, boceprevir, calpain inhibitors II and XII represent novel chemotypes that are distinct from known Mpro inhibitors. A complex crystal structure of SARS-CoV-2 Mpro with GC-376, determined at 2.15 Å resolution with three monomers per asymmetric unit, revealed two unique binding configurations, shedding light on the molecular interactions and protein conformational flexibility underlying substrate and inhibitor binding by Mpro. Overall, the compounds identified herein provide promising starting points for the further development of SARS-CoV-2 therapeutics.
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- 2020
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