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  • Open access
  • 54 Reads
Structural analyses of metallodrug/β-lactoglobulin adducts for rational design of new biomaterials

β-lactoglobulin (BLG) is a whey carrier protein of 18.4 kDa. This protein is a good system for the preparation of micro- or nanoparticles for pharmaceutical industry because of its high solubility, safe status, biodegradable nature, gel forming ability, abundance, stability at acidic pH and against gastric pepsin. It has been shown that BLG can bind anticancer Pt-based drugs and that BLG–pectin nanoparticles can transfer cytotoxic Pt compounds to cancer cells.

To study the molecular basis of the Pt-based drug recognition by BLG, we have analyzed the interaction of this protein with two extensively used anticancer metallodrugs, i.e. cisplatin and oxaliplatin, both in solution and at solid state. Structural data reveal that cisplatin binds BLG coordinating Met7, His146 and Lys8 side chains, without affecting the overall 3D structure. The molecular structure of the adduct formed upon reaction of oxaliplatin with BLG suggests the existence of a single Pt binding site. Circular Dichroism analyses reveal that the overall structure of the protein is not altered upon interaction with the metal compound.

These results suggest that BLG could act as a carrier for anticancer metallodrugs and open the way for a rational design of new biomaterials based on metallodrug/β-lactoglobulin adduct nanoparticles.

  • Open access
  • 116 Reads
Protein nanocages for anticancer metal-based drug delivery

Supramolecular protein assembly, such as cages, rings, and tubes can be used as reaction vessels and molecular templates for applications in catalysis, imaging and drug delivery.1 Ferritin (Ft) is a member of ferroxidase family of enzymes that forms a spherical nanocage. It sequesters iron by concentrating it in its internal cavity for storage and detoxification.2 Ft is very promising as a drug loading and releasing system since it is non-immunogenic, bio-compatible, highly stable, soluble in the bloodstream. It can be internalized via Ft-binding receptors (like transferrin receptor 13 or Scara54) that are over-expressed in a variety of malignant cells. Well established metallodrugs like cisplatin,5 carboplatin,6 a Pt-terpyridine compound,7 three different gold-based anticancer compounds (Auoxo3, Au2phen, Auoxo4),8-9 a bimetallic Pt-Au compound10, a bimetallic Pt-As compound and a di-ruthenium complex11 have been trapped within the Ft nanocages, taking advantage of the alkaline pH disassembly/reassembly protocol. The drug-loaded nanocomposites have been characterized by circular dichroism, to evaluate the protein secondary structure content upon drug encapsulation, and by UV-vis absorption spectroscopy, to assess the drug loading within the protein cage. ICP-MS allowed to quantify the amount of drug trapped inside the nanocage and to define metal/Ft stoichiometry, while X-ray crystallography unveiled the metallodrugs binding sites on the proteins structure and the nature of the interaction of the different compounds with Ft. The compounds often degrade upon encapsulation within the protein cage; metal-containing fragments coordinate Cys or His side chains. However, the coordination does not affect the overall cytotoxicity of the encapsulated anticancer agents, since many molecules of the metallodrugs remain trapped in the bulk within the inner core of the cage. Biological activity studies show that, even though the presence of the cage reduces the overall toxicity of the metallodrugs, the adducts of the selected compounds with Ft are generally more selective towards cancer cells than to non-malignant cells. Altogether these data indicate that encapsulation of metal-based drugs within Ft nanocages is a promising strategy to deliver these molecules to their final targets.12

  1. Maity, B.et al. Curr. Opin. Chem. Biol. (2015) 25, 88.
  2. Uchida M. et al. Am. Chem. Soc. (2006) 128, 16626.
  3. Hogemann-Savellano, D. Neoplasia (2003) 5, 495.
  4. Mendes-Jorge, L. PLoS One (2014) 9, 106974.
  5. Pontillo, N. Commun. (Camb) (2016) 52, 4136.
  6. Pontillo, N. ACS Med. Chem. Lett. (2017) 8, 433.
  7. Ferraro, G. Nanomedicine (Lond.) (2018) 13, 2995.
  8. Ferraro, G. Chem. Commun. (Camb) (2016) 52, 9518.
  9. Monti, D.M. Dalt. Trans. (2017) 46, 15454.
  10. Ferraro, G. Int J Biol Macromol. (2018) 115, 1116.
  11. Petruk, G. Chem. Med. Chem. (2019) 14, 594.
  12. Monti, D.M. Nanomedicine: N.B.M. (2019) 20 ,101997.
  • Open access
  • 98 Reads
Assessment of essential oil-loaded nanofibrous mats against the Escherichia virus MS2, a mimetic of SARS-CoV-2, for potential applications as inner layers in individual protection masks

In December 2019, a novel strain of coronavirus, SARS-CoV-2, was identified. Infected patients revealed symptoms of fever, cough (dry), sore throat, and fatigue, which began manifesting after 5 days of incubation. Hoping to prevent transmission, many countries adopted a mandatory mask use in closed public spaces. However, most mask options display a passive action against COVID-19. To overcome such restrictions, this work proposes the incorporation of anti-viral essential oils (EOs) loaded onto a nanofibrous layer that can be adapted to both community and commercial masks.

Twenty EOs selected based on their antimicrobial nature were examined for the first time against the Escherichia virus MS2. The most effective were the lemongrass (LO), Niaouli (NO) and eucalyptus (ELO) with a minimum inhibitory concentration (MIC) of 356.0 mg/mL, 365.2 mg/mL and 586.0 mg/mL, respectively. Polycaprolactone (PCL) and cellulose acetate (CA) were prepared individually at 14 wt% in chloroform/dimethylformamide (DMF) and 10 wt% in acetone/DMF, respectively, and combined at 3:1 ratio. Polymeric solutions were then processed via eletrospinning with processing parameters being optimized to 24.7 kV, 3.2 mL/h and 21 cm. Uniform, beadless nanofibers were obtained. Mats were characterized as mechanically resilient, to endure movements arising from mask positioning, and hydrophobic in nature, to repel droplets coming from the exterior. Loading of the nanofibrous mats was accomplished via physisorption using the free -OH groups of the CA as linkers. Mats were loaded with the EOs at MIC concentration for 72 h (saturation). Presence of the EOs was confirmed along the mats. Antimicrobial testing via halo determination, verified their diffusion abilities. More importantly, time-kill kinetics testing of the loaded mats attested to the EOs capability to fight the virus MS2 even when bonded to the nanofibers. Data demonstrated the potential of these EOs-loaded PCL/CA nanofibers mats to work as COVID-19 active barriers for individual protection masks.

  • Open access
  • 49 Reads
Hydrogel-like films modified with cinnamon leaf oil: a new scaffolding system capable of inhibiting Pseudomonas aeruginosa bacteria

Pseudomonas aeruginosa is considered a pathogen with clinical relevance, due to its intrinsic antibiotic resistance. For this reason, it is crucial to think of alternatives to treat P. aeruginosa-derived infections. Essential oils (EOs), natural products, possessing anti-inflammatory, antiseptic and analgesic properties, have been applied in this aim. Yet due to their volatile nature, polymeric microcapsules are frequently engineered to incorporate the antimicrobial agents at the core and work as drug carriers. As the result, the microcapsules protect the antimicrobial agents from the surrounding environment and, consequently, prevent undesirable effects, such as early degradation. In this study, a delivery platform for a controlled release of cinnamon leaf oil (CLO) was developed, resorting to chitosan (CS)/tripolyphosphate (TPP) microcapsules embedded in a hydrogel-like matrix. CS microcapsules were produced without any pH adjustment (CS1) and with pH adjusted to 5.0 (CS4). Subsequently, the microcapsules were incorporated within sodium alginate (SA) and gelatin (GN) hydrogel-like films, prepared by the solvent casting-phase inversion method. SA and GN were selected since SA presents a fast ionic gelation with divalent cations and GN has a good biodegradability. Fourier-transform infrared spectroscopy analysis confirmed the effective incorporation of CS microcapsules with CLO within the SA/GN films. A continuous release of the entrapped CLO was achieved. In addition, a matched time kill kinetics against the bacteria was attained, and the SA/GN/CS1 films were determined more efficient. Data revelated the outstanding potential of CLO loaded films for the inhibition of P. aeruginosa.

  • Open access
  • 55 Reads
Probiotics administration ameliorate azoxymethane induced-carcinogenesis by reducing the formation of aberrant crypt foci and modulation oxidative stress in rats

BACKGROUND/AIM: Aberrant crypt foci (ACF) are early lesions in the neoplastic induction found in the rat colon of the carcinogenic model. ACF is one of the first changes in the colon that lead to colorectal cancer (CRC). Probiotics and fermented foods are well known for their beneficial role in gut health and previous studies showed their therapeutic effects on gastrointestinal diseases. The aim of this study is to investigate the preventive role of Propionibacterium freudenreichii and Faecalibacterium prausnitzii probiotics against CRC Induction in rats treated with azoxymethane (AOM).

METHODS: Rats were injected subcutaneously with 7mg/kg of AOM once a week for 3 weeks, and probiotics (P. freundreichii and F. prausnitzii) were administered orally at 1×109 CFU/ml once a day for 6 weeks. 5- Fluorouracil (5-FU) as a reference anti-cancer drug was administered intraperitoneally at 35mg/kg 3 times a week for 6 weeks. After the treatment period, the colon of the rats was harvested and examined microscopically and histologically. Lipid peroxidation levels in colon tissues were measured using malondialdehyde (MDA) assay.

RESULT: Microscopical examination of harvested rat colons after methylene blue staining showed that the total number and multiplicity of ACF were significantly lower in the probiotics groups (p < 0.05) than the AOM control group that did not receive any intervention. Histological examination of the colon showed increased severe hyperplasia and dysplasia of the ACF in the AOM group compared to the treatment groups. Probiotics administration also reduced the levels of MDA in the colon of the rats compared to the rats in the AOM control group

CONCLUSION: These results suggest that probiotics play a preventive role in CRC initiation and development by slowing down ACF formation, reducing the severity of ACF lesions, and reducing lipid peroxidation levels in the colon.

  • Open access
  • 58 Reads
Role of the phytochemicals from the cocoa shell on the prevention of metabolic syndrome by an integrated network pharmacology analysis

The metabolic syndrome is a cluster of conditions that occur together, increasing the risk of chronic diseases such as obesity, type II diabetes, or cardiovascular disease. Nutritional interventions improving inflammation, bioenergetics, and oxidative stress are proposed as effective tools in preventing metabolic syndrome. The cocoa shell is a by-product generated in large amounts during cocoa production. This by-product contains alkaloids and phenolic compounds as main compounds and has been investigated as an anti-obesity and anti-diabetic agent. Here, we used network pharmacology to explore the potential mechanism of the phytochemicals from the cocoa shell. We searched the cocoa shell's phytochemical composition, and oral bioavailability and drug-likeness were screened. We predicted the cocoa shell phytochemicals' targets and used different databases to search for compound-protein and compound-gene interactions, and then protein-protein interaction networks were constructed. Moreover, pathway enrichment analysis was performed, and biological processes and signaling pathways were identified and illustrated through bioinformatics analyses. Theobromine, caffeine, procyanidin B2, (−)-epicatechin, (+)-catechin, and protocatechuic acid were identified in the cocoa shell as main components. Those phytochemicals were associated with inflammation- (TNF-α, NF-κB, JNK), oxidative stress (CAT, SOD), obesity- (adiponectin, leptin, FASN, PPAR-α), and diabetes- (insulin, AKT,) related pathways. Results demonstrated that cocoa shell phytochemicals could modulate multiple biological processes and signaling pathways in a multimechanistic manner. Hence, cocoa shell consumption could support the nutritional prevention of metabolic syndrome. Future in vivo and clinical investigations will be needed to validate this potential nutraceutical and healthy ingredient's effects and mechanisms.

  • Open access
  • 52 Reads
In vitro study of curcumin derivatives with potential antitumor activity

Curcumin (diferuloylmethane) represents a polyphenol extracted from the plant Curcuma longa which has attracted the attention of scientists for medicinal purposes. In this context, we obtained 5 different derivates in order to test their anti-tumoral effect on human cervix cancer. In this context, we obtained five curcumin derivatives, two have the structure similar with two of the natural compounds, diferuloylmethane (D4), respectively p,p-dihydroxydicinnamoylmethane (D3) and the other three have modified structures with amide or amino groups (D1, D2 and D3). The compounds were synthesized in the microwave field and characterized by 1H-NMR and 13C-NMR spectroscopy, UV-Vis and infrared spectroscopy, fluorescence and thermal analysis. Their biocompatibility was investigated on human fibroblast lung cells (MRC-5 cell line) and the anti-tumoral effect was tested on human cervix cancer cells (HeLa cell line) after 24 and 72 hours of incubation with concentrations up to 500 μg/mL of derivates. D1 and D2 derivatives decreased the number of viable tumor cells in a dose-dependent manner, and concentrations up to 200 μg/mL of these samples did not alter the viability of normal lung fibroblasts until 72 h of incubation. In addition, increased nitric oxide levels released in the cell culture media were noticed only for doses higher than 50 μg/mL. In the case of D5 sample, no changes were observed for both types of cell lines regardless the time of incubation or doses used. D3 and D4 samples killed almost all HeLa cells after the incubation with doses equal or higher than 50 μg/mL. This antitumor effect was very well correlated with an increased level of nitric oxide. However, the high doses of curcumin derivatives induced death of non-tumoral cells and must be avoided in future experiments. In conclusion, the outcomes of our study performed in vitro revealed that curcumin derivates posed minimal toxicity towards normal lung cells and the anti-proliferative efficiency results experimentally shown on cancer cells seem very promising to be further translated on in vivo studies and human clinical trials which are limited for this moment.

Acknowledgments This work was supported by a grant of the Romanian Ministry of Research and Innovation, CCCDI – UEFISCDI, project number PN-III-P2-2.1-PED-2019-1471, within PNCDI III.

  • Open access
  • 49 Reads
Optimization of metabolic stability of ligands of serotonin receptor 5-HT7 using SHAP values

There are numerous computational tools, which support the design of new potential ligands. They assist in the evaluation of potential compound activity, as well as they help in the optimization of compound physicochemical and pharmacokinetic properties. Nowadays, they are indispensable element of drug design process, as thanks to their application, both time and money can be saved.

In the study, we applied methodology based on SHAP (SHapley Additive exPlanations) values to assess metabolic stability of a series of newly designed derivatives of ligands of serotonin receptor 5-HT7. This protein is a representative of G protein-coupled receptors and constitute an important drug target, mainly for the treatment of central nervous system disorders, such as depression, cognitive disorders, anxiety and Alzheimer's disease.

The aim of application of SHAP values is to provide explanation of prediction by machine learning models, and to evaluate contributions of particular features. In the study, we used two key-based fingerprints for compound representation: MACCS keys and Klekota&Roth Fingerprint. At first, we evaluated compounds with known metabolic stability from the ChEMBL database. Then, using information provided by SHAP values from models constructed on known data, we selected features, which are important (according to the model) for metabolic stability. These information was used for the generation of new ligands of serotonin receptor 5-HT7 with the input constituted by known ligands of these receptor gathered in the ChEMBL database. After evaluation of their 5-HT7R activity via docking, the best compounds will undergo visual inspection and will be selected for purchasing and/or synthesis.

Acknowledgments : The study was supported by the grant OPUS 2018/31/B/NZ2/00165 financed by the National Science Centre, Poland (www.ncn.gov.pl)

  • Open access
  • 59 Reads
Optimization of pharmacokinetic compound profile of serotonin receptor ligands via machine learning

During the search for new active compounds, at first, the focus is put mainly on the provision of compound activity towards considered targets. However, at the same time, or in the subsequent stages, the compound need to be adequately profiled in terms of its physicochemistry and ADMET properties.

Here, we present a tool for optimization of physicochemical and pharmacokinetic properties based on the application of machine learning tools. It considered several compound properties: solubility, metabolic stability, biological membranes permeability, hERG channels blocking, and mutagenicity. Separate models are constructed for each property and the prediction power of the models is verified on the ligands of serotonin receptor 5-HT7. The models use various fingerprints for compound representation (including interaction fingerprints in the cases, where docking to the target protein can be performed).

Serotonin receptor 5-HT7 is a representative of G protein-coupled receptors – the largest and the most diverse group of proteins in the human genome. The endogenous ligand of serotonin receptor 5-HT7 (Serotonin) plays important functions in the organism, such as regulation of mood, sleep, temperature, appetite and other physiological processes and therefore, the 5-HT7R constitute important drug target for a wide range of disorders.

The results obtained within the study, will be used for the design of new serotonin receptor ligands with optimized physicochemical and ADMET profile.

Acknowledgments : The study was supported by the grant OPUS 2018/31/B/NZ2/00165 financed by the National Science Centre, Poland (www.ncn.gov.pl).

  • Open access
  • 32 Reads
Application of the 3D-QSAR methods for the development of novel, more potent D2 receptor antagonists.

20 million - this refers to the number of people who suffer from schizophrenia worldwide [1]. Hallucinations, distortions in thinking, abnormal motor behavior are the symptoms that impair the everyday life of people with schizophrenia and their families. Although numerous medications are available for this condition, many of them cause serious side effects, including agranulocytosis, sedation, or increased serum lipid concentration [2]. Extensive research has been carried out on dopamine D2 receptors. Results of these studies suggest that there are links between the impaired dopaminergic neurotransmission and the presence of characteristic symptoms of the disease [3,4]. Thus providing this group of patients with potent dopamine D2 receptor antagonists may benefit their treatment. Although multi-target ligands of aminergic G protein-coupled receptors (GPCRs) are most efficient as drugs for schizophrenia treatment, it should be emphasized that all marketed drugs against this disease are dopamine D2 receptor antagonists or partial/biased agonists.

Computer-Aided Drug Design (CADD) techniques, in particular 3D-QSAR methods, are vital in developing novel ligands. Proper understanding of the structure-activity relationship can assist the design of novel drugs characterized by low toxicity and high efficacy [5]. The CoMFA method is a widely used 3D-QSAR approach that can be implemented to correlate the steric and the electrostatic properties of a series of molecules with their pharmacological activities.

Identification of a pharmacological gap in the treatment of schizophrenia became an incentive to thoughtfully examine the structure-activity relationship among a series of dopamine D2 receptor antagonists. In our opinion, the constructed CoMFA model, characterized by good statistical parameters:(Q2=0.76, R2=0.92, F-value=338.9), will assist further drug design and enable to obtain ligands characterized by low toxicity and high bioactivity [6].

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