scholarly journals Platinum(II) O,S Complexes Inhibit the Aggregation of Amyloid Model Systems

2019 ◽  
Vol 20 (4) ◽  
pp. 829 ◽  
Author(s):  
Daniele Florio ◽  
Anna Maria Malfitano ◽  
Sarah Di Somma ◽  
Carolin Mügge ◽  
Wolfgang Weigand ◽  
...  
Keyword(s):  
Neuroblastoma Cells ◽  
Model Systems ◽  
Aggregation Process ◽  
Bidentate Ligands ◽  
Yeast Prion ◽  
Amyloid Aggregation ◽  
Binding Assays ◽  
Cinnamic Acid Derivatives ◽  
Ic50 Values ◽  
Micromolar Range

Platinum(II) complexes with different cinnamic acid derivatives as ligands were investigated for their ability to inhibit the aggregation process of amyloid systems derived from Aβ, Yeast Prion Protein Sup35p and the C-terminal domain of nucleophosmin 1. Thioflavin T binding assays and circular dichroism data indicate that these compounds strongly inhibit the aggregation of investigated peptides exhibiting IC50 values in the micromolar range. MS analysis confirms the formation of adducts between peptides and Pt(II) complexes that are also able to reduce amyloid cytotoxicity in human SH-SY5Y neuroblastoma cells. Overall data suggests that bidentate ligands based on β-hydroxy dithiocinnamic esters can be used to develop platinum or platinoid compounds with anti-amyloid aggregation properties.

scholarly journals Modulation of Amyloidogenic Peptide Aggregation by Photoactivatable CO-Releasing Ruthenium(II) Complexes

2020 ◽  
Vol 13 (8) ◽  
pp. 171 ◽  
Author(s):  
Daniele Florio ◽  
Maria Cuomo ◽  
Ilaria Iacobucci ◽  
Giarita Ferraro ◽  
Ahmed M. Mansour ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
Effective Concentration ◽  
Mass Spectrometry Data ◽  
Ionization Mass ◽  
Aggregation Process ◽  
Amyloid Aggregation ◽  
Binding Assays ◽  
Before And After ◽  
Half Maximal Effective Concentration ◽  
Micromolar Range

Three Ru(II)-based CO-releasing molecules featuring bidentate benzimidazole and terpyridine derivatives as ligands were investigated for their ability to modulate the aggregation process of the second helix of the C-terminal domain of nucleophosmin 1, namely nucleophosmin 1 (NPM1)264–277, a model amyloidogenic system, before and after irradiation at 365 nm. Thioflavin T (ThT) binding assays and UV/Vis absorption spectra indicate that binding of the compounds to the peptide inhibits its aggregation and that the inhibitory effect increases upon irradiation (half maximal effective concentration (EC50) values in the high micromolar range). Electrospray ionization mass spectrometry data of the peptide in the presence of one of these compounds confirm that the modulation of amyloid aggregation relies on the formation of adducts obtained when the Ru compounds react with the peptide upon releasing of labile ligands, like chloride and carbon monoxide. This mechanism of action explains the subtle different behavior of the three compounds observed in ThT experiments. Overall, data support the hypothesis that metal-based CO releasing molecules can be used to develop metal-based drugs with potential application as anti-amyloidogenic agents.

scholarly journals A Comparative Study of the Effects of Platinum (II) Complexes on β-Amyloid Aggregation: Potential Neurodrug Applications

2021 ◽  
Vol 22 (6) ◽  
pp. 3015
Author(s):  
Sara La Manna ◽  
Daniele Florio ◽  
Ilaria Iacobucci ◽  
Fabiana Napolitano ◽  
Ilaria De Benedictis ◽  
...  
Keyword(s):  
Neuroblastoma Cells ◽  
Platinum Complexes ◽  
Cd Spectroscopy ◽  
Amyloid Peptide ◽  
Ligand Field ◽  
Ionization Mass ◽  
Amyloid Aggregation ◽  
Binding Assays ◽  
Self Recognition ◽  
Dose Dependent

Herein the effects of three platinum complexes, namely (SP-4-2)-(2,2′-bipyridine)dichloridoplatinum(II), Pt-bpy, (SP-4-2)-dichlorido(1,10-phenanthroline) platinum(II), Pt-phen, and (SP-4-2)-chlorido(2,2′:6′,2′′-terpyridine)platinum(II) chloride, Pt-terpy, on the aggregation of an amyloid model system derived from the C-terminal domain of Aβ peptide (Aβ21–40) were investigated. Thioflavin T (ThT) binding assays revealed the ability of Pt(II) compounds to repress amyloid aggregation in a dose-dependent way, whereas the ability of Aβ21–40 peptide to interfere with ligand field of metal complexes was analyzed through UV-Vis absorption spectroscopy and electrospray ionization mass spectrometry. Spectroscopic data provided micromolar EC50 values and allowed to assess that the observed inhibition of amyloid aggregation is due to the formation of adducts between Aβ21–40 peptide and complexes upon the release of labile ligands as chloride and that they can explore different modes of coordination toward Aβ21–40 with respect to the entire Aβ1–40 polypeptide. In addition, conformational studies through circular dichroism (CD) spectroscopy suggested that Pt-terpy induces soluble β-structures of monomeric Aβ21–40, thus limiting self-recognition. Noticeably, Pt-terpy demonstrated the ability to reduce the cytotoxicity of amyloid peptide in human SH-SY5Y neuroblastoma cells. Presented data corroborate the hypothesis to enlarge the application field of already known metal-based agents to neurodegenerative diseases, as potential neurodrugs.

scholarly journals Role of the Metal Center in the Modulation of the Aggregation Process of Amyloid Model Systems by Square Planar Complexes Bearing 2-(2'-pyridyl)benzimidazole Ligands

2019 ◽  
Vol 12 (4) ◽  
pp. 154 ◽  
Author(s):  
Florio ◽  
Iacobucci ◽  
Ferraro ◽  
Mansour ◽  
Morelli ◽  
...  
Keyword(s):  
Metal Center ◽  
Model Systems ◽  
Ionization Mass ◽  
Aggregation Process ◽  
Binding Assays ◽  
Metal Compounds ◽  
Aggregation Propensity ◽  
Square Planar ◽  
Square Planar Complexes

The effect of analogue Pd(II)-, Pt(II)-, and Au(III) compounds featuring 2-(2’-pyridyl)benzimidazole on the aggregation propensity of amyloid-like peptides derived from Aβ and from the C-terminal domain of nucleophosmin 1 was investigated. Kinetic profiles of aggregation were evaluated using thioflavin binding assays, whereas the interactions of the compounds with the peptides were studied by UV-Vis absorption spectroscopy and electrospray ionization mass spectrometry. The results indicate that the compounds modulate the aggregation of the investigated peptides using different mechanisms, suggesting that the reactivity of the metal center and the physicochemical properties of the metals (rather than those of the ligands and the geometry of the metal compounds) play a crucial role in determining the anti-aggregation properties.

scholarly journals Fine-Tuning the Biological Profile of Multitarget Mitochondriotropic Antioxidants for Neurodegenerative Diseases

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 329
Author(s):  
Daniel Chavarria ◽  
Ophelie Da Silva ◽  
Sofia Benfeito ◽  
Sandra Barreiro ◽  
Jorge Garrido ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Antioxidant Properties ◽  
Neuroblastoma Cells ◽  
Oxidation Potential ◽  
Fine Tuning ◽  
Mitochondrial Oxidative Stress ◽  
Electric Eel ◽  
Ic50 Values ◽  
System Extension ◽  
Inhibition Potency

Neurotransmitter depletion and mitochondrial dysfunction are among the multiple pathological events that lead to neurodegeneration. Following our previous studies related with the development of multitarget mitochondriotropic antioxidants, this study aims to evaluate whether the π-system extension on the chemical scaffolds of AntiOXCIN2 and AntiOXCIN3 affects their bioactivity and safety profiles. After the synthesis of four triphenylphosphonium (TPP+) conjugates (compounds 2–5), we evaluated their antioxidant properties and their effect on neurotransmitter-metabolizing enzymes. All compounds were potent equine butyrylcholinesterase (eqBChE) and moderate electric eel acetylcholinesterase (eeAChE) inhibitors, with catechols 4 and 5 presenting lower IC50 values than AntiOXCIN2 and AntiOXCIN3, respectively. However, differences in the inhibition potency and selectivity of compounds 2–5 towards non-human and human cholinesterases (ChEs) were observed. Co-crystallization studies with compounds 2–5 in complex with human ChEs (hChEs) showed that these compounds exhibit different binging modes to hAChE and hBChE. Unlike AntiOXCINs, compounds 2–5 displayed moderate human monoamine oxidase (hMAO) inhibitory activity. Moreover, compounds 4 and 5 presented higher ORAC-FL indexes and lower oxidation potential values than the corresponding AntiOXCINs. Catechols 4 and 5 exhibited broader safety windows in differentiated neuroblastoma cells than benzodioxole derivatives 2 and 3. Compound 4 is highlighted as a safe mitochondria-targeted antioxidant with dual ChE/MAO inhibitory activity. Overall, this work is a contribution for the development of dual therapeutic agents addressing both mitochondrial oxidative stress and neurotransmitter depletion.

scholarly journals The Repurposed Drugs Suramin and Quinacrine Cooperatively Inhibit SARS-CoV-2 3CLpro In Vitro

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 873
Author(s):  
Raphael J. Eberle ◽  
Danilo S. Olivier ◽  
Marcos S. Amaral ◽  
Ian Gering ◽  
Dieter Willbold ◽  
...  
Keyword(s):  
Binding Mode ◽  
Drug Candidates ◽  
Main Protease ◽  
Ic50 Values ◽  
Repurposed Drugs ◽  
Antiparasitic Drugs ◽  
Inhibitory Potential ◽  
Dynamics Simulations ◽  
Micromolar Range

Since the first report of a new pneumonia disease in December 2019 (Wuhan, China) the WHO reported more than 148 million confirmed cases and 3.1 million losses globally up to now. The causative agent of COVID-19 (SARS-CoV-2) has spread worldwide, resulting in a pandemic of unprecedented magnitude. To date, several clinically safe and efficient vaccines (e.g., Pfizer-BioNTech, Moderna, Johnson & Johnson, and AstraZeneca COVID-19 vaccines) as well as drugs for emergency use have been approved. However, increasing numbers of SARS-Cov-2 variants make it imminent to identify an alternative way to treat SARS-CoV-2 infections. A well-known strategy to identify molecules with inhibitory potential against SARS-CoV-2 proteins is repurposing clinically developed drugs, e.g., antiparasitic drugs. The results described in this study demonstrated the inhibitory potential of quinacrine and suramin against SARS-CoV-2 main protease (3CLpro). Quinacrine and suramin molecules presented a competitive and noncompetitive inhibition mode, respectively, with IC50 values in the low micromolar range. Surface plasmon resonance (SPR) experiments demonstrated that quinacrine and suramin alone possessed a moderate or weak affinity with SARS-CoV-2 3CLpro but suramin binding increased quinacrine interaction by around a factor of eight. Using docking and molecular dynamics simulations, we identified a possible binding mode and the amino acids involved in these interactions. Our results suggested that suramin, in combination with quinacrine, showed promising synergistic efficacy to inhibit SARS-CoV-2 3CLpro. We suppose that the identification of effective, synergistic drug combinations could lead to the design of better treatments for the COVID-19 disease and repurposable drug candidates offer fast therapeutic breakthroughs, mainly in a pandemic moment.

scholarly journals Pipecolisporin, a Novel Cyclic Peptide with Antimalarial and Antitrypanosome Activities from a Wheat Endophytic Nigrospora oryzae

2021 ◽  
Vol 14 (3) ◽  
pp. 268
Author(s):  
Ignacio Fernández-Pastor ◽  
Victor González-Menéndez ◽  
Frederick Annang ◽  
Clara Toro ◽  
Thomas A. Mackenzie ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Agricultural Land ◽  
Cyclic Peptide ◽  
Human Cancer ◽  
Fungal Endophyte ◽  
Human Cancer Cell ◽  
Human Cancer Cell Lines ◽  
Ic50 Values ◽  
Micromolar Range ◽  
Nigrospora Oryzae

A novel cyclic antimalarial and antitrypanosome hexapeptide, pipecolisporin (1), was isolated from cultures of Nigrospora oryzae CF-298113, a fungal endophyte isolated from roots of Triticum sp. collected in a traditional agricultural land of Montefrío, Granada, Spain. The structure of this compound, including its absolute configuration, was elucidated by HRMS, 1-D and 2-D NMR spectroscopy, and Marfey’s analysis. This metabolite displayed interesting activity against Plasmodium falciparum and Trypanosoma cruzi, with IC50 values in the micromolar range, and no significant cytotoxicity against the human cancer cell lines A549, A2058, MCF7, MIA PaCa-2, and HepG2.

scholarly journals Use of Half-Generation PAMAM Dendrimers (G0.5–G3.5) with Carboxylate End-Groups to Improve the DACHPtCl2 and 5-FU Efficacy as Anticancer Drugs

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2924
Author(s):  
Cláudia Camacho ◽  
Helena Tomás ◽  
João Rodrigues
Keyword(s):  
Cancer Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Anticancer Drug ◽  
Water Solubility ◽  
Cancer Cell Lines ◽  
Pamam Dendrimers ◽  
Binding Assays ◽  
End Groups ◽  
Ic50 Values

The DACHPtCl2 compound (trans-(R,R)-1,2-diaminocyclohexanedichloroplatinum(II)) is a potent anticancer drug with a broad spectrum of activity and is less toxic than oxaliplatin (trans-l-diaminocyclohexane oxalate platinum II), with which it shares the active metal fragment DACHPt. Nevertheless, due to poor water solubility, its use as a chemotherapeutic drug is limited. Here, DACHPtCl2 was conjugated, in a bidentate form, with half-generation PAMAM dendrimers (G0.5–G3.5) with carboxylate end-groups, and the resulting conjugates were evaluated against various types of cancer cell lines. In this way, we aimed at increasing the solubility and availability at the target site of DACHPt while potentially reducing the adverse side effects. DNA binding assays showed a hyperchromic effect compatible with DNA helix’s disruption upon the interaction of the metallodendrimers and/or the released active metallic fragments with DNA. Furthermore, the prepared DACHPt metallodendrimers presented cytotoxicity in a wide set of cancer cell lines used (the relative potency regarding oxaliplatin was in general high) and were not hemotoxic. Importantly, their selectivity for A2780 and CACO-2 cancer cells with respect to non-cancer cells was particularly high. Subsequently, the anticancer drug 5-FU was loaded in a selected metallodendrimer (the G2.5COO(DACHPt)16) to investigate a possible synergistic effect between the two drugs carried by the same dendrimer scaffold and tested for cytotoxicity in A2780cisR and CACO-2 cancer cell lines. This combination resulted in IC50 values much lower than the IC50 for 5-FU but higher than those found for the metallodendrimers without 5-FU. It seems, thus, that the metallic fragment-induced cytotoxicity dominates over the cytotoxicity of 5-FU in the set of considered cell lines.

scholarly journals Valorization of Apple Peels through the Study of the Effects on the Amyloid Aggregation Process of κ-Casein

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2371
Author(s):  
Valeria Guarrasi ◽  
Giacoma Cinzia Rappa ◽  
Maria Assunta Costa ◽  
Fabio Librizzi ◽  
Marco Raimondo ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Environmental Sustainability ◽  
Bovine Milk ◽  
Amyloid Formation ◽  
Aggregation Process ◽  
Amyloid Aggregation ◽  
Social Challenges ◽  
Force Microscopy ◽  
Atomic Force ◽  
Apple Peels

Waste valorization represents one of the main social challenges when promoting a circular economy and environmental sustainability. Here, we evaluated the effect of the polyphenols extracted from apple peels, normally disposed of as waste, on the amyloid aggregation process of κ-casein from bovine milk, a well-used amyloidogenic model system. The effect of the apple peel extract on protein aggregation was examined using a thioflavin T fluorescence assay, Congo red binding assay, circular dichroism, light scattering, and atomic force microscopy. We found that the phenolic extract from the peel of apples of the cultivar “Fuji”, cultivated in Sicily (Caltavuturo, Italy), inhibited κ-casein fibril formation in a dose-dependent way. In particular, we found that the extract significantly reduced the protein aggregation rate and inhibited the secondary structure reorganization that accompanies κ-casein amyloid formation. Protein-aggregated species resulting from the incubation of κ-casein in the presence of polyphenols under amyloid aggregation conditions were reduced in number and different in morphology.

scholarly journals Novel Selective IDO1 Inhibitors with Isoxazolo[5,4-d]pyrimidin-4(5H)-one Scaffold

2021 ◽  
Vol 14 (3) ◽  
pp. 265
Author(s):  
Ana Dolšak ◽  
Tomaž Bratkovič ◽  
Larisa Mlinarič ◽  
Eva Ogorevc ◽  
Urban Švajger ◽  
...  
Keyword(s):  
Systematic Investigation ◽  
The Novel ◽  
Indoleamine 2,3 Dioxygenase ◽  
Tryptophan Dioxygenase ◽  
Promising Target ◽  
Synthetic Procedure ◽  
Ic50 Values ◽  
Novel Scaffold ◽  
Further Development ◽  
Micromolar Range

Indoleamine 2,3-dioxygenase 1 (IDO1) is a promising target in immunomodulation of several pathological conditions, especially cancers. Here we present the synthesis of a series of IDO1 inhibitors with the novel isoxazolo[5,4-d]pyrimidin-4(5H)-one scaffold. A focused library was prepared using a 6- or 7-step synthetic procedure to allow a systematic investigation of the structure-activity relationships of the described scaffold. Chemistry-driven modifications lead us to the discovery of our best-in-class inhibitors possessing p-trifluoromethyl (23), p-cyclohexyl (32), or p-methoxycarbonyl (20, 39) substituted aniline moieties with IC50 values in the low micromolar range. In addition to hIDO1, compounds were tested for their inhibition of indoleamine 2,3-dioxygenase 2 and tryptophan dioxygenase, and found to be selective for hIDO1. Our results thus demonstrate a successful study on IDO1-selective isoxazolo[5,4-d]pyrimidin-4(5H)-one inhibitors, defining promising chemical probes with a novel scaffold for further development of potent small-molecule immunomodulators.

scholarly journals Development of Binding Assays for the SH2 Domain of Grb7 and Grb2 Using Fluorescence Polarization

2008 ◽  
Vol 13 (2) ◽  
pp. 112-119 ◽  
Author(s):  
Jean-Philippe Luzy ◽  
Huixiong Chen ◽  
Brunilde Gril ◽  
Wang-Qing Liu ◽  
Michel Vidal ◽  
...  
Keyword(s):  
Fluorescence Polarization ◽  
Adaptor Proteins ◽  
Specific Protein ◽  
Sh2 Domain ◽  
Enzyme Linked Immunosorbent Assay ◽  
Binding Assays ◽  
Protein Targets ◽  
Src Homology 2 ◽  
Src Homology ◽  
Micromolar Range

Adaptor proteins Grb7 and Grb2 have been implicated as being 2 potential therapeutic targets in several human cancers, especially those that overexpress ErbB2. These 2 proteins contain both a SH2 domain (Src homology 2) that binds to phosphorylated tyrosine residues contained within ErbB2 and other specific protein targets. Two assays based on enzyme-linked immunosorbent assay and fluorescence polarization methods have been developed and validated to find and rank inhibitors for both proteins binding to the pY1139. Fluorescence polarization assays allowed the authors to determine quickly and reproducibly affinities of peptides from low nanomolar to high micromolar range and to compare them directly for Grb7 and Grb2. As a result, the assays have identified a known peptidomimetic Grb2 SH2 inhibitor (mAZ-pTyr-(αMe)pTyr-Asn-NH2) that exhibits the most potent affinity for the Grb7 SH2 domain described to date. ( Journal of Biomolecular Screening 2008:112-119)

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