Publications by authors named "Andrea Brancale"

171 Publications

A Computer-Based Methodology to Design Non-Standard Peptides Potentially Able to Prevent HOX-PBX1-Associated Cancer Diseases.

Int J Mol Sci 2021 May 26;22(11). Epub 2021 May 26.

School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff CF10 3NB, UK.

In the last decades, HOX proteins have been extensively studied due to their pivotal role in transcriptional events. HOX proteins execute their activity by exploiting a cooperative binding to PBX proteins and DNA. Therefore, an increase or decrease in HOX activity has been associated with both solid and haematological cancer diseases. Thus, inhibiting HOX-PBX interaction represents a potential strategy to prevent these malignancies, as demonstrated by the patented peptide HTL001 that is being studied in clinical trials. In this work, a computational study is described to identify novel potential peptides designed by employing a database of non-natural amino acids. For this purpose, residue scanning of the HOX minimal active sequence was performed to select the mutations to be further processed. According to these results, the peptides were point-mutated and used for Molecular Dynamics (MD) simulations in complex with PBX1 protein and DNA to evaluate complex binding stability. MM-GBSA calculations of the resulting MD trajectories were exploited to guide the selection of the most promising mutations that were exploited to generate twelve combinatorial peptides. Finally, the latter peptides in complex with PBX1 protein and DNA were exploited to run MD simulations and the ΔG average values of the complexes were calculated. Thus, the analysis of the results highlighted eleven combinatorial peptides that will be considered for further assays.
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http://dx.doi.org/10.3390/ijms22115670DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8198631PMC
May 2021

Concise synthesis and biological evaluation of 2-Aryl-3-Anilinobenzo[b]thiophene derivatives as potent apoptosis-inducing agents.

Bioorg Chem 2021 Jul 20;112:104919. Epub 2021 Apr 20.

Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy.

Many clinically used agents active in cancer chemotherapy exert their activity through the induction of cell death (apoptosis) by targeting microtubules, altering protein function or inhibiting DNA synthesis. The benzo[b]thiophene scaffold holds a pivotal place as a pharmacophore for the development of anticancer agents, and, in addition, this scaffold has many pharmacological activities. We have developed a flexible method for the construction of a new series of 2-aryl-3-(3,4,5-trimethoxyanilino)-6-methoxybenzo[b]thiophenes as potent antiproliferative agents, giving access to a wide range of substitution patterns at the 2-position of the 6-methoxybenzo[b]thiophene common intermediate. In the present study, all the synthesized compounds retained the 3-(3,4,5-trimethoxyanilino)-6-methoxybenzo[b]thiophene moiety, and the structure-activity relationship was examined by modification of the aryl group at its 2-position with electron-withdrawing (F) or electron-releasing (alkyl and alkoxy) groups. We found that small substituents, such as fluorine or methyl, could be placed in the para-position of the 2-phenyl ring, and these modifications only slightly reduced antiproliferative activity relative to the unsubstituted 2-phenyl analogue. Compounds 3a and 3b, bearing the phenyl and para-fluorophenyl at the 2-position of the 6-methoxybenzo[b]thiophene nucleus, respectively, exhibited the greatest antiproliferative activity among the tested compounds. The treatment of both Caco2 (not metastatic) and HCT-116 (metastatic) colon carcinoma cells with 3a or 3b triggered a significant induction of apoptosis as demonstrated by the increased expression of cleaved-poly(ADP-ribose) polymerase (PARP), receptor-interacting protein (RIP) and caspase-3 proteins. The same effect was not observed with non-transformed colon 841 CoN cells. A potential additional effect during mitosis for 3a in metastatic cells and for 3b in non-metastatic cells was also observed.
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http://dx.doi.org/10.1016/j.bioorg.2021.104919DOI Listing
July 2021

Structure property relationships of N-acylsulfonamides and related bioisosteres.

Eur J Med Chem 2021 Jun 28;218:113399. Epub 2021 Mar 28.

Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA. Electronic address:

The N-acylsulfonamide functional group is a feature of the pharmacophore of several biologically active molecules, including marketed drugs. Although this acidic moiety presents multiple points of attachments that could be exploited to introduce structural diversification, depending on the circumstances, the replacement of the functional group itself with a suitable surrogate, or bioisostere, may be desirable. A number of N-acylsulfonamide bioisosteres have been developed over the years that provide opportunities to modulate both structure and physicochemical properties of this important structural motif. To enable an assessment of the relative impact on physicochemical properties that these replacements may have compared to the N-acylsulfonamide group, we conducted a structure-property relationship study based on matched molecular pairs, in which the N-acylsulfonamide moiety of common template reference structures is replaced with a series of bioisosteres. The data presented, which include an assessment of relative changes in acidity, permeability, lipophilicity and intrinsic solubility, provides a basis for informed decisions when deploying N-acylsulfonamides, or surrogates thereof, in analog design.
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http://dx.doi.org/10.1016/j.ejmech.2021.113399DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8105289PMC
June 2021

Targeting the Complement Serine Protease MASP-2 as a Therapeutic Strategy for Coronavirus Infections.

Viruses 2021 02 17;13(2). Epub 2021 Feb 17.

Department of Chemistry, College of Science and Engineering, Swansea University, Swansea SA28PP, UK.

MASP-2, mannose-binding protein-associated serine protease 2, is a key enzyme in the lectin pathway of complement activation. Hyperactivation of this protein by human coronaviruses SARS-CoV, MERS-CoV and SARS-CoV-2 has been found to contribute to aberrant complement activation in patients, leading to aggravated lung injury with potentially fatal consequences. This hyperactivation is triggered in the lungs through a conserved, direct interaction between MASP-2 and coronavirus nucleocapsid (N) proteins. Blocking this interaction with monoclonal antibodies and interfering directly with the catalytic activity of MASP-2, have been found to alleviate coronavirus-induced lung injury both in vitro and in vivo. In this study, a virtual library of 8736 licensed drugs and clinical agents has been screened in silico according to two parallel strategies. The first strategy aims at identifying direct inhibitors of MASP-2 catalytic activity, while the second strategy focusses on finding protein-protein interaction inhibitors (PPIs) of MASP-2 and coronaviral N proteins. Such agents could represent promising support treatment options to prevent lung injury and reduce mortality rates of infections caused by both present and future-emerging coronaviruses. Forty-six drug repurposing candidates were purchased and, for the ones selected as potential direct inhibitors of MASP-2, a preliminary in vitro assay was conducted to assess their interference with the lectin pathway of complement activation. Some of the tested agents displayed a dose-response inhibitory activity of the lectin pathway, potentially providing the basis for a viable support strategy to prevent the severe complications of coronavirus infections.
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http://dx.doi.org/10.3390/v13020312DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7923061PMC
February 2021

The Discovery of a Novel Antimetastatic Bcl3 Inhibitor.

Mol Cancer Ther 2021 05 1;20(5):775-786. Epub 2021 Mar 1.

School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, Wales, United Kingdom.

The development of antimetastatic drugs is an urgent healthcare priority for patients with cancer, because metastasis is thought to account for around 90% of cancer deaths. Current antimetastatic treatment options are limited and often associated with poor long-term survival and systemic toxicities. Bcl3, a facilitator protein of the NF-κB family, is associated with poor prognosis in a range of tumor types. Bcl3 has been directly implicated in the metastasis of tumor cells, yet is well tolerated when constitutively deleted in murine models, making it a promising therapeutic target. Here, we describe the identification and characterization of the first small-molecule Bcl3 inhibitor, by using a virtual drug design and screening approach against a computational model of the Bcl3-NF-kB1(p50) protein-protein interaction. From selected virtual screening hits, one compound (JS6) showed potent intracellular Bcl3-inhibitory activity. JS6 treatment led to reductions in Bcl3-NF-kB1 binding, tumor colony formation, and cancer cell migration ; and tumor stasis and antimetastatic activity , while being devoid of overt systemic toxicity. These results represent a successful application of screening in the identification of protein-protein inhibitors for novel intracellular targets, and confirm Bcl3 as a potential antimetastatic target.
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http://dx.doi.org/10.1158/1535-7163.MCT-20-0283DOI Listing
May 2021

Sulfonated cryogel scaffolds for focal delivery in ex-vivo brain tissue cultures.

Biomaterials 2021 04 10;271:120712. Epub 2021 Feb 10.

Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, D-01307, Dresden, Germany; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, MRC Centre for Neurodevelopmental Disorders, King's College London, London, SE1 1UL, United Kingdom. Electronic address:

The human brain has unique features that are difficult to study in animal models, including the mechanisms underlying neurodevelopmental and psychiatric disorders. Despite recent advances in human primary brain tissue culture systems, the use of these models to elucidate cellular disease mechanisms remains limited. A major reason for this is the lack of tools available to precisely manipulate a specific area of the tissue in a reproducible manner. Here we report an easy-to-use tool for site-specific manipulation of human brain tissue in culture. We show that line-shaped cryogel scaffolds synthesized with precise microscale dimensions allow the targeted delivery of a reagent to a specific region of human brain tissue in culture. 3-sulfopropyl acrylate (SPA) was incorporated into the cryogel network to yield a negative surface charge for the reversible binding of molecular cargo. The fluorescent dyes BODIPY and DiI were used as model cargos to show that placement of dye loaded scaffolds onto brain tissue in culture resulted in controlled delivery without a burst release, and labelling of specific regions without tissue damage. We further show that cryogels can deliver tetrodotoxin to tissue, inhibiting neuronal function in a reversible manner. The robust nature and precise dimensions of the cryogel resulted in a user-friendly and reproducible tool to manipulate primary human tissue cultures. These easy-to-use cryogels offer an innovate approach for more complex manipulations of ex-vivo tissue.
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http://dx.doi.org/10.1016/j.biomaterials.2021.120712DOI Listing
April 2021

A facile synthesis of diaryl pyrroles led to the discovery of potent colchicine site antimitotic agents.

Eur J Med Chem 2021 Mar 29;214:113229. Epub 2021 Jan 29.

Istituto di Ricerca Pediatrica (IRP), Corso Stati Uniti 4, 35128, Padova, Italy. Electronic address:

Three different series of cis-restricted analogues of combretastatin A-4 (CA-4), corresponding to thirty-nine molecules that contained a pyrrole nucleus interposed between the two aryl rings, were prepared by a palladium-mediated coupling approach and evaluated for their antiproliferative activity against six human cancer cell lines. In the two series of 1,2-diaryl pyrrole derivatives, results suggested that the presence of the 3',4',5'-trimethoxyphenyl moiety at the N-1 position of the pyrrole ring was more favorable for antiproliferative activity. In the series of 3,4-diarylpyrrole analogues, three compounds (11i-k) exhibited maximal antiproliferative activity, showing excellent antiproliferative activity against the CA-4 resistant HT-29 cells. Inhibition of tubulin polymerization of selected 1,2 pyrrole derivatives (9a, 9c, 9o and 10a) was similar to that observed with CA-4, while the isomeric 3,4-pyrrole analogues 11i-k were generally from 1.5- to 2-fold more active than CA-4. Compounds 11j and 11k were the only compounds that showed activity as inhibitors of colchicine binding comparable to that CA-4. Compound 11j had biological properties consistent with its intracellular target being tubulin. This compound was able to block the cell cycle in metaphase and to induce significant apoptosis at a concentration of 25 nM, following the mitochondrial pathway, with low toxicity for normal cells. More importantly, compound 11j exerted activity in vivo superior to that of CA-4P, being able to significantly reduce tumor growth in a syngeneic murine tumor model even at the lower dose tested (5.0 mg/kg).
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http://dx.doi.org/10.1016/j.ejmech.2021.113229DOI Listing
March 2021

Evaluation of the Structure-Activity Relationship of Microtubule-Targeting 1,2,4-Triazolo[1,5-]pyrimidines Identifies New Candidates for Neurodegenerative Tauopathies.

J Med Chem 2021 01 7;64(2):1073-1102. Epub 2021 Jan 7.

Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States.

Studies in tau and Aβ plaque transgenic mouse models demonstrated that brain-penetrant microtubule (MT)-stabilizing compounds, including the 1,2,4-triazolo[1,5-]pyrimidines, hold promise as candidate treatments for Alzheimer's disease and related neurodegenerative tauopathies. Triazolopyrimidines have already been investigated as anticancer agents; however, the antimitotic activity of these compounds does not always correlate with stabilization of MTs in cells. Indeed, previous studies from our laboratories identified a critical role for the fragment linked at C6 in determining whether triazolopyrimidines promote MT stabilization or, conversely, disrupt MT integrity in cells. To further elucidate the structure-activity relationship (SAR) and to identify potentially improved MT-stabilizing candidates for neurodegenerative disease, a comprehensive set of 68 triazolopyrimidine congeners bearing structural modifications at C6 and/or C7 was designed, synthesized, and evaluated. These studies expand upon prior understanding of triazolopyrimidine SAR and enabled the identification of novel analogues that, relative to the existing lead, exhibit improved physicochemical properties, MT-stabilizing activity, and pharmacokinetics.
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http://dx.doi.org/10.1021/acs.jmedchem.0c01605DOI Listing
January 2021

Identification of 6-(piperazin-1-yl)-1,3,5-triazine as a chemical scaffold with broad anti-schistosomal activities.

Wellcome Open Res 2020 13;5:169. Epub 2020 Nov 13.

Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, SY23 3DA, UK.

Schistosomiasis, caused by infection with blood fluke schistosomes, is a neglected tropical disease of considerable importance in resource-poor communities throughout the developing world. In the absence of an immunoprophylactic vaccine and due to over-reliance on a single chemotherapy (praziquantel), schistosomiasis control is at risk should drug insensitive schistosomes develop. In this context, application of virtual screening on validated schistosome targets has proven successful in the identification of novel small molecules with anti-schistosomal activity.   Focusing on the histone methylation machinery, we herein have used RNA interference (RNAi), ELISA-mediated detection of H3K4 methylation, homology modelling and virtual screening to identify a small collection of small molecules for anti-schistosomal testing. A combination of low to high-throughput whole organism assays were subsequently used to assess these compounds' activities on miracidia to sporocyst transformation, schistosomula phenotype/motility metrics and adult worm motility/oviposition readouts. RNAi-mediated knockdown of (encoding a histone methyltransferase, HMT) in adult worms (~60%) reduced parasite motility and egg production. Moreover, docking of compounds into Smp_138030/SmMLL-1's homology model highlighted competitive substrate pocket inhibitors, some of which demonstrated significant activity on miracidia, schistosomula and adult worm lifecycle stages together with variable effects on HepG2 cells. Particularly, the effect of compounds containing a 6-(piperazin-1-yl)-1,3,5-triazine core on adult schistosomes recapitulated the results of the RNAi screens. The biological data and the structure-activity relationship presented in this study define the 6-(piperazin-1-yl)-1,3,5-triazine core as a promising starting point in ongoing efforts to develop new urgently needed schistosomicides.
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http://dx.doi.org/10.12688/wellcomeopenres.16069.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7459852PMC
November 2020

Discovery of Novel 2-Aniline-1,4-naphthoquinones as Potential New Drug Treatment for Leber's Hereditary Optic Neuropathy (LHON).

J Med Chem 2020 11 12;63(22):13638-13655. Epub 2020 Nov 12.

School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, Wales, U.K.

Leber's hereditary optic neuropathy (LHON) is a rare genetic mitochondrial disease and the primary cause of chronic visual impairment for at least 1 in 10 000 individuals in the U.K. Treatment options remain limited, with only a few drug candidates and therapeutic approaches, either approved or in development. Recently, idebenone has been investigated as drug therapy in the treatment of LHON, although evidence for the efficacy of idebenone is limited in the literature. NAD(P)H:quinone oxidoreductase 1 (NQO1) and mitochondrial complex III were identified as the major enzymes involved in idebenone activity. Based on this mode of action, computer-aided techniques and structure-activity relationship (SAR) optimization studies led to the discovery of a series naphthoquinone-related small molecules, with comparable adenosine 5'-triphosphate (ATP) rescue activity to idebenone. Among these, three compounds showed activity in the nanomolar range and one, 2-((4-fluoro-3-(trifluoromethyl)phenyl)amino)-3-(methylthio)naphthalene-1,3-dione (), demonstrated significantly higher potency ex vivo, and significantly lower cytotoxicity, than idebenone.
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http://dx.doi.org/10.1021/acs.jmedchem.0c00942DOI Listing
November 2020

Rational design of highly potent broad-spectrum enterovirus inhibitors targeting the nonstructural protein 2C.

PLoS Biol 2020 11 6;18(11):e3000904. Epub 2020 Nov 6.

Virology Section, Infectious Disease and Immunology Division, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.

There is a great need for antiviral drugs to treat enterovirus (EV) and rhinovirus (RV) infections, which can be severe and occasionally life-threatening. The conserved nonstructural protein 2C, which is an AAA+ ATPase, is a promising target for drug development. Here, we present a structure-activity relationship study of a previously identified compound that targets the 2C protein of EV-A71 and several EV-B species members, but not poliovirus (PV) (EV-C species). This compound is structurally related to the Food and Drug Administration (FDA)-approved drug fluoxetine-which also targets 2C-but has favorable chemical properties. We identified several compounds with increased antiviral potency and broadened activity. Four compounds showed broad-spectrum EV and RV activity and inhibited contemporary strains of emerging EVs of public health concern, including EV-A71, coxsackievirus (CV)-A24v, and EV-D68. Importantly, unlike (S)-fluoxetine, these compounds are no longer neuroactive. By raising resistant EV-A71, CV-B3, and EV-D68 variants against one of these inhibitors, we identified novel 2C resistance mutations. Reverse engineering of these mutations revealed a conserved mechanism of resistance development. Resistant viruses first acquired a mutation in, or adjacent to, the α2 helix of 2C. This mutation disrupted compound binding and provided drug resistance, but this was at the cost of viral fitness. Additional mutations at distantly localized 2C residues were then acquired to increase resistance and/or to compensate for the loss of fitness. Using computational methods to identify solvent accessible tunnels near the α2 helix in the EV-A71 and PV 2C crystal structures, a conserved binding pocket of the inhibitors is proposed.
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http://dx.doi.org/10.1371/journal.pbio.3000904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7673538PMC
November 2020

Synthesis and biological evaluation of novel flexible nucleoside analogues that inhibit flavivirus replication in vitro.

Bioorg Med Chem 2020 11 31;28(22):115713. Epub 2020 Aug 31.

Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD, USA. Electronic address:

Flaviviruses, such as Dengue (DENV) and Zika (ZIKV) viruses, represent a severe health burden. There are currently no FDA-approved treatments, and vaccines against most flaviviruses are still lacking. We have developed several flexible analogues ("fleximers") of the FDA-approved nucleoside Acyclovir that exhibit activity against various RNA viruses, demonstrating their broad-spectrum potential. The current study reports activity against DENV and Yellow Fever Virus (YFV), particularly for compound 1. Studies to elucidate the mechanism of action suggest the flex-analogue triphosphates, especially 1-TP, inhibit DENV and ZIKV methyltransferases, and a secondary, albeit weak, effect on the DENV RNA-dependent RNA polymerase was observed at high concentrations. The results of these studies are reported herein.
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http://dx.doi.org/10.1016/j.bmc.2020.115713DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7457965PMC
November 2020

Computational Studies towards the Identification of Novel Rhodopsin-Binding Compounds as Chemical Chaperones for Misfolded Opsins.

Molecules 2020 Oct 23;25(21). Epub 2020 Oct 23.

Department of Chemistry, Swansea University, Swansea SA2 8PP, UK.

Accumulation of misfolded and mistrafficked rhodopsin on the endoplasmic reticulum of photoreceptor cells has a pivotal role in the pathogenesis of retinitis pigmentosa and a subset of Leber's congenital amaurosis. One potential strategy to reduce rhodopsin misfolding and aggregation in these conditions is to use opsin-binding compounds as chemical chaperones for opsin. Such molecules have previously shown the ability to aid rhodopsin folding and proper trafficking to the outer cell membranes of photoreceptors. As means to identify novel chemical chaperones for rhodopsin, a structure-based virtual screening of commercially available drug-like compounds (300,000) was performed on the main binding site of the visual pigment chromophore, the 11--retinal. The best 24 virtual hits were examined for their ability to compete for the chromophore-binding site of opsin. Among these, four small molecules demonstrated the ability to reduce the rate constant for the formation of the 9--retinal-rhodopsin complex, while five molecules surprisingly enhanced the formation of this complex. Compound , , and showed a weak but detectable increase in the trafficking of the P23H mutant, widely used as a model for both retinitis pigmentosa and Leber's congenital amaurosis, from the ER to the cell membrane. The compounds did not show any relevant cytotoxicity in two different human cell lines, with the only exception of . Based on the structures of these active compounds, a series of in silico studies gave important insights on the potential structural features required for a molecule to act either as chemical chaperone or as stabiliser of the 11--retinal-rhodopsin complex. Thus, this study revealed a series of small molecules that represent a solid foundation for the future development of novel therapeutics against these severe inherited blinding diseases.
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http://dx.doi.org/10.3390/molecules25214904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7660337PMC
October 2020

Novel Nucleoside Analogues as Effective Antiviral Agents for Zika Virus Infections.

Molecules 2020 Oct 20;25(20). Epub 2020 Oct 20.

School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK.

Previously considered a neglected , Zika virus has recently emerged as a public health concern due to its ability to spread rapidly and cause severe neurological disorders, such as microcephaly in newborn babies from infected mothers, and Guillain-Barré syndrome in adults. Despite extensive efforts towards the identification of effective therapies, specific antivirals are still not available. As part of ongoing medicinal chemistry studies to identify new antiviral agents, we screened against Zika virus replication in vitro in a targeted internal library of small-molecule agents, comprising both nucleoside and non-nucleoside agents. Among the compounds evaluated, novel aryloxyphosphoramidate prodrugs of the nucleosides 2'-C-methyl-adenosine, 2-CMA, and 7-deaza-2'C-methyl-adenosine, 7-DMA, were found to significantly inhibit the virus-induced cytopathic effect in multiple relevant cell lines. In addition, one of these prodrugs exhibits a synergistic antiviral effect against Zika virus when applied in combination with an indirect antiviral agent, a l-dideoxy bicyclic pyrimidine nucleoside analogue, which potently inhibits vaccinia and measles viruses in vitro by targeting a host pathway. Our findings provide a solid basis for further development of an antiviral therapy for Zika virus infections, possibly exploiting a dual approach combining two different agents, one targeting the viral polymerase (direct-acting antiviral), the second targeting a host-directed autophagy mechanism.
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http://dx.doi.org/10.3390/molecules25204813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594033PMC
October 2020

Diketo acids inhibit the cap-snatching endonuclease of several Bunyavirales.

Antiviral Res 2020 11 24;183:104947. Epub 2020 Sep 24.

KU Leuven, Rega Institute for Medical Research, Belgium. Electronic address:

Several fatal bunyavirus infections lack specific treatment. Here, we show that diketo acids engage a panel of bunyavirus cap-snatching endonucleases, inhibit their catalytic activity and reduce viral replication of a taxonomic representative in vitro. Specifically, the non-salt form of L-742,001 and its derivatives exhibited EC values between 5.6 and 6.9 μM against a recombinant BUNV-mCherry virus. Structural analysis and molecular docking simulations identified traits of both the class of chemical entities and the viral target that could help the design of novel, more potent molecules for the development of pan-bunyavirus antivirals.
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http://dx.doi.org/10.1016/j.antiviral.2020.104947DOI Listing
November 2020

Enhanced efficacy of endonuclease inhibitor baloxavir acid against orthobunyaviruses when used in combination with ribavirin.

J Antimicrob Chemother 2020 11;75(11):3189-3193

KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium.

Objectives: Baloxavir acid is an endonuclease inhibitor approved for use against influenza. We evaluated whether this compound also targets the endonuclease domain of orthobunyaviruses and therefore could potentially be used against orthobunyavirus infections.

Methods: We performed a thermal shift assay and a fluorescence resonance energy transfer (FRET)-based nuclease monitoring assay using the La Crosse virus (LACV) endonuclease and baloxavir acid to prove their interaction and identify an inhibitory effect. Their interaction was further studied in a docking simulation using Glide SP. We show that baloxavir acid inhibits the viral replication of Bunyamwera virus (BUNV)-mCherry in vitro using high-content imaging and virus yield assay. Lastly, we investigated the use of baloxavir acid in combination with ribavirin in vitro by implementing the Zero Interaction Potency response surface model.

Results: We show that baloxavir acid augments LACV enzyme's melting temperature with ΔTm 9.5 ± 0.4°C and inhibited substrate cleavage with IC50 0.39 ± 0.03 μM. Moreover, our docking simulation suggests that baloxavir acid is able to establish an efficient binding with the LACV endonuclease. In the cell-based assay, we observed that baloxavir acid and ribavirin inhibited BUNV-mCherry with an EC50 of 0.7 ± 0.2 μM and 26.6 ± 8.9 μM, respectively. When used in combination, we found a maximum synergistic effect of 8.64.

Conclusions: The influenza endonuclease inhibitor baloxavir acid is able to bind to and interfere with the endonuclease domain of orthobunyaviruses and yields a more potent antiviral effect than ribavirin against BUNV-mCherry. The combination of both compounds results in a more potent antiviral effect, suggesting that these molecules could potentially be combined to treat orthobunyavirus-infected patients.
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http://dx.doi.org/10.1093/jac/dkaa337DOI Listing
November 2020

Focal drug administration via heparin-containing cryogel microcarriers reduces cancer growth and metastasis.

Carbohydr Polym 2020 Oct 3;245:116504. Epub 2020 Jun 3.

Leibniz-Institut für Polymerforschung Dresden, Max Bergmann Center of Biomaterials Dresden, Hohe Straße 6, D-01069, Dresden, Germany; Technische Universität Dresden, Center for Regenerative Therapies Dresden, Fetscherstr. 105, 01307, Dresden, Germany.

Developing drug delivery systems that release anticancer drugs in a controlled and sustained manner remains challenging. We hypothesized that highly sulfated heparin-based microcarriers would allow electrostatic drug binding and controlled release. In silico modelling showed that the anticancer drug doxorubicin has affinity for the heparin component of the microcarriers. Experimental results showed that the strong electrostatic interaction was reversible, allowing both doxorubicin loading and a subsequent slow release over 42 days without an initial burst release. The drug-loaded microcarriers were able to reduce cancer cell viability in vitro in both hormone-dependent and highly aggressive triple-negative human breast cancer cells. Focal drug treatment, of an in vivo orthotopic triple-negative breast cancer model significantly decreased tumor burden and reduced cancer metastasis, whereas systemic administration of an equivalent drug dose was ineffective. This study proves that heparin-based microcarriers can be used as drug delivery platforms, for focal delivery and sustained long-term drug release.
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http://dx.doi.org/10.1016/j.carbpol.2020.116504DOI Listing
October 2020

Modeling Epac1 interactions with the allosteric inhibitor AM-001 by co-solvent molecular dynamics.

J Comput Aided Mol Des 2020 11 22;34(11):1171-1179. Epub 2020 Jul 22.

Department of Drug Chemistry and Technologies, Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.

The exchange proteins activated by cAMP (EPAC) are implicated in a large variety of physiological processes and they are considered as promising targets for a wide range of therapeutic applications. Several recent reports provided evidence for the therapeutic effectiveness of the inhibiting EPAC1 activity cardiac diseases. In that context, we recently characterized a selective EPAC1 antagonist named AM-001. This compound was featured by a non-competitive mechanism of action but the localization of its allosteric site to EPAC1 structure has yet to be investigated. Therefore, we performed cosolvent molecular dynamics with the aim to identify a suitable allosteric binding site. Then, the docking and molecular dynamics were used to determine the binding of the AM-001 to the regions highlighted by cosolvent molecular dynamics for EPAC1. These analyses led us to the identification of a suitable allosteric AM-001 binding pocket at EPAC1. As a model validation, we also evaluated the binding poses of the available AM-001 analogues, with a different biological potency. Finally, the complex EPAC1 with AM-001 bound at the putative allosteric site was further refined by molecular dynamics. The principal component analysis led us to identify the protein motion that resulted in an inactive like conformation upon the allosteric inhibitor binding.
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http://dx.doi.org/10.1007/s10822-020-00332-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7533256PMC
November 2020

Characterizing the original anti-C5 function-blocking antibody, BB5.1, for species specificity, mode of action and interactions with C5.

Immunology 2020 10 13;161(2):103-113. Epub 2020 Jul 13.

Systems Immunity University Research Institute, School of Medicine, Cardiff University, Cardiff, UK.

The implication of complement in multiple diseases over the last 20 years has fuelled interest in developing anti-complement drugs. To date, the focus has been on C5; blocking cleavage of C5 prevents formation of two pro-inflammatory activities, C5a anaphylatoxin and membrane attack complex. The concept of C5 blockade to inhibit inflammation dates back 30 years to the description of BB5.1, an anti-C5 blocking monoclonal antibody raised in C5-deficient mice. This antibody proved an invaluable tool to demonstrate complement involvement in mouse disease models and catalysed enthusiasm for anti-complement drug development, culminating in the anti-human C5 monoclonal antibody eculizumab, the most successful anti-complement drug to date, already in clinical use for several rare diseases. Despite its key role in providing proof-of-concept for C5 blockade, the mechanism of BB5.1 inhibition remains poorly understood. Here, we characterized BB5.1 cross-species inhibition, C5 binding affinity and chain specificity. BB5.1 efficiently inhibited C5 in mouse serum but not in human or other rodent sera; it prevented C5 cleavage and C5a generation. BB5.1 bound the C5 α-chain with high affinity and slow off-rate. BB5.1 complementarity-determining regions were obtained and docking algorithms were used to predict the likely binding interface on mouse C5.
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http://dx.doi.org/10.1111/imm.13228DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7496778PMC
October 2020

Drosophila taste neurons as an agonist-screening platform for P2X receptors.

Sci Rep 2020 05 19;10(1):8292. Epub 2020 May 19.

School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK.

The P2X receptor family of ATP-gated cation channels are attractive drug targets for pain and inflammatory disease, but no subtype-selective agonists, and few partially selective agonists have been described to date. As proof-of-concept for the discovery of novel P2X receptor agonists, here we demonstrate the use of Drosophila taste neurons heterologously expressing rat P2X2 receptors as a screening platform. We demonstrate that wild-type rat P2X2 expressed in Drosophila is fully functional (ATP EC 8.7 µM), and that screening of small (2 µl) volumes of a library of 80 adenosine nucleotide analogues is rapid and straightforward. We have determined agonist potency and specificity profiles for rat P2X2 receptors; triphosphate-bearing analogues display broad activity, tolerating a number of substitutions, and diphosphate and monophosphate analogues display very little activity. While several ATP analogues gave responses of similar magnitude to ATP, including the previously identified agonists ATPγS and ATPαS, we were also able to identify a novel agonist, the synthetic analogue 2-fluoro-ATP, and to confirm its agonist activity on rat P2X2 receptors expressed in human cells. These data validate our Drosophila platform as a useful tool for the analysis of agonist structure-activity relationships, and for the screening and discovery of novel P2X receptor agonists.
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http://dx.doi.org/10.1038/s41598-020-65169-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7237442PMC
May 2020

Design, synthesis, in vitro and in vivo biological evaluation of 2-amino-3-aroylbenzo[b]furan derivatives as highly potent tubulin polymerization inhibitors.

Eur J Med Chem 2020 Aug 12;200:112448. Epub 2020 May 12.

Dipartimento di Salute della Donna e del Bambino, Laboratorio di Oncoematologia, Università di Padova, 35131, Padova, Italy. Electronic address:

A new class of inhibitors of tubulin polymerization based on the 2-amino-3-(3',4',5'-trimethoxybenzoyl)benzo[b]furan molecular scaffold was synthesized and evaluated for in vivo and in vitro biological activity. These derivatives were synthesized with different electron-releasing or electron-withdrawing substituents at one of the C-4 through C-7 positions. Methoxy substitution and location on the benzene part of the benzo[b]furan ring played an important role in affecting antiproliferative activity, with the greatest activity occurring with the methoxy group at the C-6 position, the least with the substituent at C-4. The same effect was also observed with ethoxy, methyl or bromine at the C-6 position of the benzo[b]furan skeleton, with the 6-ethoxy-2-amino-3-(3',4',5'-trimethoxybenzoyl)benzo[b]furan derivative 4f as the most promising compound of the series. This compound showed remarkable antiproliferative activity (IC: 5 pM) against the Daoy medulloblastoma cell line, and 4f was nearly devoid of toxicity on healthy human lymphocytes and astrocytes. The potent antiproliferative activity of 4f was derived from its inhibition of tubulin polymerization by binding to the colchicine site. The compound was also examined for in vivo activity, showing higher potency at 15 mg/kg compared with the reference compound combretastatin A-4 phosphate at 30 mg/kg against a syngeneic murine mammary tumor.
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http://dx.doi.org/10.1016/j.ejmech.2020.112448DOI Listing
August 2020

Synthesis and Biological Evaluation of 2-Substituted Benzyl-/Phenylethylamino-4-amino-5-aroylthiazoles as Apoptosis-Inducing Anticancer Agents.

Molecules 2020 May 6;25(9). Epub 2020 May 6.

Dipartimento di Scienze Chimiche e Farmaceutiche, University of Ferrara, Via L. Borsari 46, 44121 Ferrara, Italy.

Induction of apoptosis is a common chemotherapeutic mechanism to kill cancer cells The thiazole system has been reported over the past decades as a building block for the preparation of anticancer agents. A novel series of 2-arylalkylamino-4-amino-5-(3',4',5'-trimethoxybenzoyl)-thiazole derivatives designed as dual inhibitors of tubulin and cyclin-dependent kinases (CDKs) were synthesized and evaluated for their antiproliferative activity in vitro against two cancer cell lines and, for selected highly active compounds, for interactions with tubulin and cyclin-dependent kinases and for cell cycle and apoptosis effects. Structure-activity relationships were elucidated for various substituents at the 2-position of the thiazole skeleton. Among the synthesized compounds, the most active analogues were found to be the -chlorobenzylamino derivative as well as the -chloro and -methoxyphenethylamino analogues and , respectively, which inhibited the growth of U-937 and SK-MEL-1 cancer cell lines with IC values ranging from 5.7 to 12.2 μM. On U-937 cells, the tested compounds and induced apoptosis in a time and concentration dependent manner. These two latter molecules did not affect tubulin polymerization (IC > 20 μM) nor CDK activity at a single concentration of 10 μM, suggesting alternative targets than tubulin and CDK for the compounds.
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http://dx.doi.org/10.3390/molecules25092177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7248693PMC
May 2020

Synthesis and Biological Evaluation of New Antitubulin Agents Containing 2-(3',4',5'-trimethoxyanilino)-3,6-disubstituted-4,5,6,7-tetrahydrothieno[2,3-]pyridine Scaffold.

Molecules 2020 Apr 7;25(7). Epub 2020 Apr 7.

Dipartimento di Scienze della Vita e Biotecnologie, Università di Ferrara, 44121 Ferrara, Italy.

Two novel series of compounds based on the 4,5,6,7-tetrahydrothieno[2,3-]pyridine and 4,5,6,7-tetrahydrobenzo[]thiophene molecular skeleton, characterized by the presence of a 3',4',5'-trimethoxyanilino moiety and a cyano or an alkoxycarbonyl group at its 2- or 3-position, respectively, were designed, synthesized, and evaluated for antiproliferative activity on a panel of cancer cell lines and for selected highly active compounds, inhibition of tubulin polymerization, and cell cycle effects. We have identified the 2-(3',4',5'-trimethoxyanilino)-3-cyano-6-methoxycarbonyl-4,5,6,7-tetrahydrothieno[2,3-]pyridine derivative and its 6-ethoxycarbonyl homologue as new antiproliferative agents that inhibit cancer cell growth with IC values ranging from 1.1 to 4.7 μM against a panel of three cancer cell lines. Their interaction with tubulin at micromolar levels leads to the accumulation of cells in the G2/M phase of the cell cycle and to an apoptotic cell death. The cell apoptosis study found that compounds and were very effective in the induction of apoptosis in a dose-dependent manner. These two derivatives did not induce cell death in normal human peripheral blood mononuclear cells, suggesting that they may be selective against cancer cells. Molecular docking studies confirmed that the inhibitory activity of these molecules on tubulin polymerization derived from binding to the colchicine site.
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http://dx.doi.org/10.3390/molecules25071690DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7181277PMC
April 2020

Synthesis and antiviral effect of novel fluoxetine analogues as enterovirus 2C inhibitors.

Antiviral Res 2020 06 29;178:104781. Epub 2020 Mar 29.

School of Pharmacy & Pharmaceutical Sciences, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB, UK. Electronic address:

Enteroviruses (EV) are a group of positive-strand RNA (+RNA) viruses that include many important human pathogens (e.g. poliovirus, coxsackievirus, echovirus, numbered enteroviruses and rhinoviruses). Fluoxetine was identified in drug repurposing screens as potent inhibitor of enterovirus B and enterovirus D replication. In this paper we are reporting the synthesis and the antiviral effect of a series of fluoxetine analogues. The results obtained offer a preliminary insight into the structure-activity relationship of its chemical scaffold and confirm the importance of the chiral configuration. We identified a racemic fluoxetine analogue, 2b, which showed a similar antiviral activity compared to (S)-fluoxetine. Investigating the stereochemistry of 2b revealed that the S-enantiomer exerts potent antiviral activity and increased the antiviral spectrum compared to the racemic mixture of 2b. In line with the observed antiviral effect, the S-enantiomer displayed a dose-dependent shift in the melting temperature in thermal shift assays, indicative for direct binding to the recombinant 2C protein.
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http://dx.doi.org/10.1016/j.antiviral.2020.104781DOI Listing
June 2020

Suramin Inhibits Chikungunya Virus Replication by Interacting with Virions and Blocking the Early Steps of Infection.

Viruses 2020 03 17;12(3). Epub 2020 Mar 17.

Department of Medical Microbiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.

Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that can cause a debilitating disease that is primarily characterized by persistent joint pain. CHIKV has been emerging globally, while neither a vaccine nor antiviral medication is available. The anti-parasitic drug suramin was previously shown to inhibit CHIKV replication. In this study we aimed to obtain more detailed insight into its mechanism of action. We found that suramin interacts with virions and can inhibit virus binding to cells. It also appeared to inhibit post-attachment steps of the infection process, likely by preventing conformational changes of the envelope glycoproteins required for fusion and the progression of infection. Suramin-resistant CHIKV strains were selected and genotyping and reverse genetics experiments indicated that mutations in E2 were responsible for resistance. The substitutions N5R and H18Q were reverse engineered in the E2 glycoprotein in order to understand their role in resistance. The binding of suramin-resistant viruses with these two E2 mutations was inhibited by suramin like that of wild-type virus, but they appeared to be able to overcome the post-attachment inhibitory effect of suramin. Conversely, a virus with a G82R mutation in E2 (implicated in attenuation of vaccine strain 181/25), which renders it dependent on the interaction with heparan sulfate for entry, was more sensitive to suramin than wild-type virus. Using molecular modelling studies, we predicted the potential suramin binding sites on the mature spikes of the chikungunya virion. We conclude that suramin interferes with CHIKV entry by interacting with the E2 envelope protein, which inhibits attachment and also interferes with conformational changes required for fusion.
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http://dx.doi.org/10.3390/v12030314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7150963PMC
March 2020

Rational modifications, synthesis and biological evaluation of new potential antivirals for RSV designed to target the M2-1 protein.

Bioorg Med Chem 2020 04 26;28(8):115401. Epub 2020 Feb 26.

Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, King Edward VII Avenue, Cardiff CF103NB, UK; Department of Chemistry, Swansea University, Swansea, UK.

Respiratory syncytial virus (RSV) is the main cause of lower respiratory tract diseases in infants and young children, with potentially serious and fatal consequences associated with severe infections. Despite extensive research efforts invested in the identification of therapeutic measures, no vaccine is currently available, while treatment options are limited to ribavirin and palivizumab, which both present significant limitations. While clinical and pre-clinical candidates mainly target the viral fusion protein, the nucleocapsid protein or the viral polymerase, our focus has been the identification of new antiviral compounds targeting the viral M2-1 protein, thanks to the presence of a zinc-ejecting group in their chemical structure. Starting from an anti-RSV hit we had previously identified with an in silico structure-based approach, we have designed, synthesised and evaluated a new series of dithiocarbamate analogues, with which we have explored the antiviral activity of this scaffold. The findings presented in this work may provide the basis for the identification of a new antiviral lead to treat RSV infections.
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http://dx.doi.org/10.1016/j.bmc.2020.115401DOI Listing
April 2020

In Vitro Topical Delivery of Chlorhexidine to the Cornea: Enhancement Using Drug-Loaded Contact Lenses and β-Cyclodextrin Complexation, and the Importance of Simulating Tear Irrigation.

Mol Pharm 2020 04 20;17(4):1428-1441. Epub 2020 Mar 20.

School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Wales, Cardiff CF10 3NB, U.K.

Microbial keratitis is a severe, sight-threatening condition caused by various pathogens. Eyedrops are the standard delivery modality for treating these disorders; however, blinking reflex, elevated tear production, and nasolacrimal drainage eliminate much of the instilled dose within a few seconds. Therefore, eyedrops must be applied repeatedly for prolonged periods. The present study aimed to probe more effective ocular delivery of chlorhexidine based upon drug-loaded hydrogel contact lenses and β-cyclodextrin (β-CD), while also determining the effect of constant irrigation with simulated tear fluid (STF) in in vitro experiments. Chlorhexidine digluconate (as 0.2 and 2% solutions, β-CD inclusion complexes, and loaded hydrogel contact lenses) were applied to enucleated porcine eyes as single or multiple 10 μL doses, or as drug-loaded contact lenses, with and without β-CD. The corneas were then excised and drug-extracted quantified by high-performance liquid chromatography (HPLC). The effect of constant irrigation by STF was evaluated to test the effect of increased tear production on corneal delivery. Potential antimicrobial activity of the delivered drug was also assessed. Results showed that drug-loaded contact lenses delivered the greatest amount of chlorhexidine into the cornea over a 24 h period, while the eyedrop solution comparator delivered the least. The β-CD significantly enhanced chlorhexidine delivery to the cornea from eyedrop solution, although contact lenses loaded with chlorhexidine-β-CD failed to enhance delivery. β-CD within the hydrogel matrix impeded drug release. Constant irrigation with STF significantly reduced the amount of drug delivered to the cornea in all cases. Chlorhexidine retained antimicrobial activity in all delivery methods. Hydrogel contact lenses loaded with chlorhexidine delivered significantly higher levels to the cornea compared to eyedrops, either multiple hourly doses or a single dose. They also offer reduced application, in particular, to a nonulcerated corneal infection. Finally, the importance of fully accounting for tear production in in vitro ocular delivery experiments was highlighted.
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http://dx.doi.org/10.1021/acs.molpharmaceut.0c00140DOI Listing
April 2020

Design, synthesis and biological evaluation of 2-alkoxycarbonyl-3-anilinoindoles as a new class of potent inhibitors of tubulin polymerization.

Bioorg Chem 2020 04 18;97:103665. Epub 2020 Feb 18.

Rega Institute for Medical Research, KU Leuven, Laboratory of Virology and Chemotherapy, Leuven, Belgium.

A new class of inhibitors of tubulin polymerization based on the 2-alkoxycarbonyl-3-(3',4',5'-trimethoxyanilino)indole molecular skeleton was synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization and cell cycle effects. The results presented show that the methoxy substitution and location on the indole nucleus plays an important role in inhibition of cell growth, and the most favorable position for the substituent was at C-6. In addition, a small-size ester function (methoxy/ethoxycarbonyl) at the 2-position of the indole core was desirable. Also, analogues that were alkylated with methyl, ethyl or n-propyl groups or had a benzyl moiety on the N-1 indolic nitrogen retained activity equivalent to those observed in the parent N-1H analogues. The most promising compounds of the series were 2-methoxycarbonyl-3-(3',4'.5'-trimethoxyanilino)-5-methoxyindole 3f and 1-methyl-2-methoxycarbonyl-3-(3',4'.5'-trimethoxyanilino)-6-methoxy-indole 3w, both of which target tubulin at the colchicine site with antitubulin activities comparable to that of the reference compound combretastatin A-4.
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http://dx.doi.org/10.1016/j.bioorg.2020.103665DOI Listing
April 2020

A new antiviral scaffold for human norovirus identified with computer-aided approaches on the viral polymerase.

Sci Rep 2019 12 5;9(1):18413. Epub 2019 Dec 5.

Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff, King Edward VII Avenue, Cardiff, CF103NB, UK.

Human norovirus is the leading cause of acute gastroenteritis worldwide, affecting every year 685 million people. In about one third of cases, this virus affects children under five years of age, causing each year up to 200,000 child deaths, mainly in the developing countries. Norovirus outbreaks are associated with very significant economic losses, with an estimated societal cost of 60 billion dollars per year. Despite the marked socio-economic consequences associated, no therapeutic options or vaccines are currently available to treat or prevent this infection. One promising target to identify new antiviral agents for norovirus is the viral polymerase, which has a pivotal role for the viral replication and lacks closely homologous structures in the host. Starting from the scaffold of a novel class of norovirus polymerase inhibitors recently discovered in our research group with a computer-aided method, different new chemical modifications were designed and carried out, with the aim to identify improved agents effective against norovirus replication in cell-based assays. While different new inhibitors of the viral polymerase were found, a further computer-aided ligand optimisation approach led to the identification of a new antiviral scaffold for norovirus, which inhibits human norovirus replication at low-micromolar concentrations.
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http://dx.doi.org/10.1038/s41598-019-54903-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6895199PMC
December 2019

The repositioning of epigenetic probes/inhibitors identifies new anti-schistosomal lead compounds and chemotherapeutic targets.

PLoS Negl Trop Dis 2019 11 15;13(11):e0007693. Epub 2019 Nov 15.

Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, United Kingdom.

Background: Praziquantel represents the frontline chemotherapy used to treat schistosomiasis, a neglected tropical disease (NTD) caused by infection with macro-parasitic blood fluke schistosomes. While this drug is safe, its inability to kill all schistosome lifecycle stages within the human host often requires repeat treatments. This limitation, amongst others, has led to the search for novel anti-schistosome replacement or combinatorial chemotherapies. Here, we describe a repositioning strategy to assess the anthelmintic activity of epigenetic probes/inhibitors obtained from the Structural Genomics Consortium.

Methodology/principle Findings: Thirty-seven epigenetic probes/inhibitors targeting histone readers, writers and erasers were initially screened against Schistosoma mansoni schistosomula using the high-throughput Roboworm platform. At 10 μM, 14 of these 37 compounds (38%) negatively affected schistosomula motility and phenotype after 72 hours of continuous co-incubation. Subsequent dose-response titrations against schistosomula and adult worms revealed epigenetic probes targeting one reader (NVS-CECR2-1), one writer (LLY-507 and BAY-598) and one eraser (GSK-J4) to be particularly active. As LLY-507/BAY-598 (SMYD2 histone methyltransferase inhibitors) and GSK-J4 (a JMJD3 histone demethylase inhibitor) regulate an epigenetic process (protein methylation) known to be critical for schistosome development, further characterisation of these compounds/putative targets was performed. RNA interference (RNAi) of one putative LLY-507/BAY-598 S. mansoni target (Smp_000700) in adult worms replicated the compound-mediated motility and egg production defects. Furthermore, H3K36me2, a known product catalysed by SMYD2 activity, was also reduced by LLY-507 (25%), BAY-598 (23%) and siSmp_000700 (15%) treatment of adult worms. Oviposition and packaging of vitelline cells into in vitro laid eggs was also significantly affected by GSK-J4 (putative cell permeable prodrug inhibitor of Smp_034000), but not by the related structural analogue GSK-J1 (cell impermeable inhibitor).

Conclusion/significance: Collectively, these results provide further support for the development of next-generation drugs targeting schistosome epigenetic pathway components. In particular, the progression of histone methylation/demethylation modulators presents a tractable strategy for anti-schistosomal control.
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http://dx.doi.org/10.1371/journal.pntd.0007693DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6881072PMC
November 2019