Tumor-Targeting Peptides Search Strategy for the Delivery of Therapeutic and Diagnostic Molecules to Tumor Cells

Background: The combination of the unique properties of cancer cells makes it possible to find specific ligands that interact directly with the tumor, and to conduct targeted tumor therapy. Phage display is one of the most common methods for searching for specific ligands. Bacteriophages display peptides, and the peptides themselves can be used as targeting molecules for the delivery of diagnostic and therapeutic agents. Phage display can be performed both in vitro and in vivo. Moreover, it is possible to carry out the phage display on cells pre-enriched for a certain tumor marker, for example, CD44 and CD133. Methods: For this work we used several methods, such as phage display, sequencing, cell sorting, immunocytochemistry, phage titration. Results: We performed phage display using different screening systems (in vitro and in vivo), different phage libraries (Ph.D-7, Ph.D-12, Ph.D-C7C) on CD44+/CD133+ and without enrichment U-87 MG cells. The binding efficiency of bacteriophages displayed tumor-targeting peptides on U-87 MG cells was compared in vitro. We also conducted a comparative analysis in vivo of the specificity of the accumulation of selected bacteriophages in the tumor and in the control organs (liver, brain, kidney and lungs). Conclusions: The screening in vivo of linear phage peptide libraries for glioblastoma was the most effective strategy for obtaining tumor-targeting peptides providing targeted delivery of diagnostic and therapeutic agents to glioblastoma.     

Extracellular Vesicle MicroRNA That Are Involved in β-Thalassemia Complications

Beta thalassemia major (βT) is a hereditary anemia characterized by transfusion-dependency, lifelong requirement of chelation, and organ dysfunction. MicroRNA (miRNA) can be packed into extracellular vesicles (EVs) that carry them to target cells. We explored EV-miRNA in βT and their pathophysiologic role. Circulating EVs were isolated from 35 βT-patients and 15 controls. EV miRNA was evaluated by nano-string technology and real-time quantitative polymerase chain reaction (RT-qPCR). We explored effects of EVs on cell culture proliferation, apoptosis, and signal transduction. Higher amounts of small EV (exosomes) were found in patients than in controls. The expression of 21 miRNA was > two-fold higher, and of 17 miRNA < three-fold lower in βT-EVs than control-EVs. RT-qPCR confirmed differential expression of six miRNAs in βT, particularly miR-144-3p, a regulator of erythropoiesis. Exposure of endothelial, liver Huh7, and pancreatic 1.1B4 cells to βT-EVs significantly reduced cell viability and increased cell apoptosis. βT-EV-induced endothelial cell apoptosis involved the MAPK/JNK signal-transduction pathway. In contrast, splenectomized βT-EVs induced proliferation of bone marrow mesenchymal stem cells (BM-MSC). In summary, the miR-144-3p was strongly increased; βT-EVs induced apoptosis and decreased endothelial, pancreatic, and liver cell survival while supporting BM-MSC proliferation. These mechanisms may contribute to βT organ dysfunction and complications.     

Development and Characterization of New Peptidomimetic Inhibitors of the West Nile Virus NS2B–NS3 Protease

A series of new substrate analogue inhibitors of the WNV NS2B–NS3 protease containing decarboxylated arginine mimetics at the P1 position was developed. Among the various analogues, trans‐(4‐guanidino)cyclohexylmethylamide (GCMA) was identified as the most suitable P1 residue. In combination with dichloro‐substituted phenylacetyl groups at the P4 position, three inhibitors with inhibition constants of <0.2 μM were obtained. These GCMA inhibitors have a better selectivity profile than the previously described agmatine analogues, and possess negligible affinity for the trypsin‐like serine proteases thrombin, factor Xa, and matriptase. A crystal structure in complex with the WNV protease was determined for one of the most potent inhibitors, 3,4‐dichlorophenylacetyl‐Lys‐Lys‐GCMA (K_i=0.13 μM ). The inhibitor adopts a horseshoe‐like conformation, most likely due to a hydrophobic contact between the P4 phenyl ring and the P1 cyclohexyl group, which is further stabilized by an intramolecular hydrogen bond between the P1 guanidino group and the P4 carbonyl oxygen atom. These inhibitors are stable, readily accessible, and have a noncovalent binding mode. Therefore, they may serve as suitable lead structures for further development.     

Preparation and properties of catalyzed polyimide/dicyanate semi‐interpenetrating networks for polymer gas membrane with suppressed CO2‐plasticization

The work presents an approach to reduce the plasticization of polymeric membranes caused by condensable gases, and particularly the effect of plasticization caused on polyimides by CO₂ at high pressure. A technical polyimide, Matrimid^®, was chosen as a reference of polyimide membrane and the approach applied consisted of incorporating reactive oligomers to have cross‐linkable mixed systems, which do not plasticize at high CO₂ pressure. Films of semi‐interpenetrating networks (semi‐IPNs) based on Matrimid^® and phenolphthalein dicyanate as cross‐linking monomer in ratios 90/10, 80/20, and 70/30, were prepared using a catalyst to lower the curing temperature from 280 to 180°C. Semi‐IPNs properties such as thermal stability, mechanical properties, glass transition temperatures, or density were measured to characterize the films and were correlated with the dicyanate monomer content. The CO₂ gas permeation behavior of the three semi‐IPNs was studied using a CO₂ feed pressure ranging from 1 to 30 atm. The gas separation properties were mainly explained attending to the density of the films, which depended on the dicyanate content used. In the three catalyzed semi‐IPNs, the CO₂ permeability coefficients remained almost constant all along the investigated range of CO₂ pressure while Matrimid^® treated at 180°C did show a clear tendency to plasticization over a critical feed pressure of about 17 bar. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

On the modeling of the co2‐catalyzed sintering of calcium oxide

A comprehensive mathematical model for the CO₂‐catalyzed sintering of CaO is proposed. It takes into account the mechanisms of surface diffusion and grain boundary diffusion, catalyzed by CO₂ chemisorption and dissolution, respectively. In addition, the model proposed here considers the change in pore size distribution during sintering, grain growth, and the densification by lattice diffusion, which is the intrinsic sintering mechanism of the CaO. Model predictions are validated using experimental data on the sintering of two CaO samples, one of them derived from pure CaCO₃ and the other from limestone. It is found that impurities in limestone‐derived CaO do not significantly affect the CO₂ dissolution or chemisorption processes; however, they strongly increase the rate of sintering by lattice diffusion. It is also established that low temperatures and CO₂ partial pressures promote the coarsening by surface diffusion, whereas high temperatures and CO₂ partial pressures favor densification. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3286–3296, 2017     

Viscoelastic and thermal properties of woven‐sisal‐fabric‐reinforced natural‐rubber biocomposites

Textile–rubber biocomposites were prepared by the reinforcement of natural rubber with woven sisal fabric. The viscoelastic properties of the composites were analyzed at different frequencies. Sisal fabric was subjected to different chemical modifications, such as mercerization, silanation, and thermal treatment, and the influences of the modifications on the dynamic mechanical properties were analyzed. The storage modulus was found to increase with reinforcement of natural rubber with woven sisal fabric. The chemical modification of the sisal fabric resulted in a decrease in the storage modulus. The damping factor was found to decrease with chemical treatment, and the gum compound exhibited maximum damping characteristics. The thermal stabilities of the composites were also analyzed by thermogravimetric studies. Scanning electron microscopy studies were performed to evaluate the morphology of the fabric–matrix interface.© 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

α‐Ketoheterocycles as Inhibitors of Leishmania mexicana Cysteine Protease CPB

Cysteine proteases of the papain superfamily are present in nearly all eukaryotes and also play pivotal roles in the biology of parasites. Inhibition of cysteine proteases is emerging as an important strategy to combat parasitic diseases such as sleeping sickness, Chagas disease, and leishmaniasis. Inspired by the in vivo antiparasitic activity of the vinylsulfone‐based cysteine protease inhibitors, a series of α‐ketoheterocycles were developed as reversible inhibitors of a recombinant L. mexicana cysteine protease, CPB2.8. Three isoxazoles and especially one oxadiazole compound are potent reversible inhibitors of CPB2.8; however, in vitro whole‐organism screening against a panel of protozoan parasites did not fully correlate with the observed inhibition of the cysteine protease.     

Synthesis of Bicyclic N‐Arylmethyl‐Substituted Iminoribitol Derivatives as Selective Nucleoside Hydrolase Inhibitors

A series of bicyclic N ‐arylmethyl‐substituted iminoribitols were synthesised and evaluated in vitro against T. vivax nucleoside hydrolase. The importance of the N–Asp40 interaction was confirmed and depends on an optimal pK_a value, which can be influenced by substituents. The compounds were active inhibitors of nucleoside hydrolase (IAG‐NH) and are inactive against human purine nucleoside phosphorylase.

     

Stabilization of Ethyl‐Cellulose Oleogel Network Using Lauric Acid

The use of oleogels in a wide range of applications requires a broad diversity of gel properties tailored for each purpose. The current research explores the combination of ethyl‐cellulose (EC) with lauric acid (LA), at different ratios with an emphasis to explore each component contribution and function in the gel structure and properties. The results suggest that oleogel physical properties strongly depend on the EC concentration. A transition from antagonistic to synergistic behavior between EC and LA with respect to the mechanical properties is observed above 4 wt% polymer. This behavior is seen in all LA concentrations, suggesting that the main effect arises from the EC while the LA acts as a stabilizer. In addition, LA reduces EC gelation temperature from approximately 140 °C to 79–101 °C, depending on the EC concentration, suggesting a ‘plasticizing’ effect. The recovery ability of EC oleogel after large amplitude deformation is improved from 16% to 34% due to the LA crystalline nature. LA crystal structure is not affected by EC concentration; however its crystallization temperature shifts to a lower temperature. Practical Applications: These results provide a broad overview of the composition‐function relation obtained while combining EC with LA.     

Effect of pigmentation on polyurethane/polysiloxane hybrid coatings

Rutile TiO₂ was formulated into polyurethane/polysiloxane hybrid coatings in order to investigate the influence of pigmentation on the inorganic phase of the hybrid coatings. Two urethanes were prepared from the isocyanurate of hexane diisocyanate (HDI), alkoxysilane modified HDI, and tetraethyl orthosilicate (TEOS) oligomers, with oligoesters derived from either cyclohexane diacids (CHDA) and 2‐butyl‐2‐ethyl‐1,3‐propanediol (BEPD) or adipic acid (AA), isophthalic acid (IPA), 1,6‐hexanediol (HD), and trimethylol propane (TMP). The oligoesters were spectroscopically characterized using GPC, FT‐IR, and NMR. Chemical interaction between the TiO₂ and the sol–gel precursor was investigated using solid‐state ²⁹Si NMR and XPS. The morphology, mechanical, viscoelastic, thermal properties of the pigmented coatings are evaluated as a function of pigmentation volume concentration (PVC). Using AFM and SEM, the pigment was observed to be well dispersed in the polymer binder. The thermal stability, the tensile modulus, and strength of the coatings were enhanced with increasing PVC, whereas the pull‐off adhesion and flexibility (elongation‐at‐break) were reduced with increasing PVC. Finally, the pigmented coatings were evaluated by electrochemical impedance spectroscopy (EIS) and the results showed that 10 wt % of the pigment improved the corrosion resistance of the entire coating system. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42947.