Репозиторий Университета

© 2020 Elsevier B.V. Amphiphilic maleic acid-containing copolymers account for a recent methodical breakthrough in the study of membrane proteins. Their application enables a detergent-free extraction of membrane proteins from lipid bilayers, yielding stable water-soluble, discoidal lipid bilayer particles with incorporated proteins, which are wrapped with copolymers. Although many studies confirm the potential of this approach for membrane protein research, the interactions between the maleic acid-containing copolymers and extracted lipids, as well as possible effects of the copolymers on lipid-embedded proteins deserve further scrutinization. Here, we combine electron paramagnetic resonance spectroscopy and coarse-grain molecular dynamics simulations to compare the distribution and dynamics of lipids in lipid particles of phospholipid bilayers encased either by an aliphatic diisobutylene/maleic acid copolymer (DIBMALPs) or by an aromatic styrene/maleic acid copolymer (SMALPs). Nitroxides located at the 5th, 12th or 16th carbon atom positions in phosphatidylcholine-based spin labels experience restrictions of their reorientational motion depending on the type of encasing copolymer. The dynamics of the lipids was less constrained in DIBMALPs than in SMALPs with the affinity of spin labeled lipids to the polymeric rim being more pronounced in SMALPs.

© 2018 Elsevier B.V. Development of efficient biodegradable, environmentally responsive, biocompatible and non-toxic delivery system is needed for efficient gene delivery. As well known, properties of the vehicle are determined by the structure of carrier components. The aim of the current study was to estimate in vitro transfection efficacy of aliphatic di-, tri- and tetrapeptide-based cationic lipoplexes loaded with siRNA in function of a number of cationic groups using 2D (monolayer culture) and 3D (multicellular tumor spheroids) in vitro models. Physicochemical properties and cytotoxicity of the liposomes were found to be dependent upon a number of amino acid derivatives in an amphiphilic polar head. Uptake of liposomes loaded with nucleic acid (lipoplexes) and their localization in HEK293T cells was studied by confocal microscopy. The liposomes based on lipotripeptides had the highest transfection efficiency which was 20-fold higher than those fabricated from lipotetrapeptides.

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The liposomal form of silibinin was obtained, and its antihepatotoxic activity in mice was studied using a model of acute toxic hepatitis caused by injection of carbon tetrachloride or paracetamol. It was shown that the use of the drug in therapy or prevention regimens leads to normalization of levels of transaminases and total protein in the blood of experimental animals. The results of the study showed that liposomal silibinin when administered intravenously shows a more pronounced hepatoprotective effect compared to intragastric administration of free silibinin. Thus, the effectiveness of the therapeutic action of silibinin can be significantly increased by using its liposomal form. Liposomal drug, in contrast to native silibinin, can be injected directly into the blood that significantly increases its bioavailability.

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The composite Y14/siUTR, a complex consisting of cationic lipopeptide Y14 as an excipient and pharmaceutical substance of small interfering RNAtargeted against the UTR region of hepatitis C virus (siUTR), was investigated. The composite was intended to inhibit the hepatitis C virus replication cycle. The present work was aimed at developing pharmaceutical analytical methods for the components of this composite using HPLC-UV and UV spectroscopy.

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Tetra(aryl)tetracyanoporphyrazines are the promising group of dyes for photodynamic therapy of tumors with unique combination of photosensitizer properties and sensitivity of fluorescence parameters to the environment viscosity. However, in vivo application of such hydrophobic photosensitizers requires using of drug carriers ensuring efficient delivery to the tumor site. The present study is focused on obtaining liposomes loaded with tetrakis(4-benzyloxyphenyl)tetracyanoporphyrazine and examining their properties depending on lipid composition. An efficient loading of the dye and a high long-term stability were proved for the liposomes composed of phosphatidylcholine with cholesterol and phosphatidylglycerol. This can be explained by the presence of negatively charged lipids in the bilayer and, as a consequence, a high value of the surface potential. A high rate of cellular uptake and a strong photoinduced toxicity give the prerequisites for the further use of the liposomal form of the photosensitizer for photodynamic therapy of tumors.

© 2018 Tomsk State University. All Rights Reserved.  Sanguinarine is a benzophenanthridine alkaloid with antimicrobial, antiviral, antiparasitic, anti-inflammatory, antiplatelet, antiangiogenic, and antitumor activity. One of the important properties of sanguinarine is a pronounced ability to suppress thrombogenesis, tumor growth and metastasis. However, the low solubility of sanguinarine in biological fluids limits its medical use. The present research was devoted to the development of the liposomal form of sanguinarine and the study of its biological activity. We obtained liposomes with sanguinarine on the basis of lecithin and cholesterol by the method of hydration of a thin film with buffer, followed by sonication and extrusion through a polycarbonate membrane with a pore size of 100 nm. Purification of liposomal dispersion from a drug that was not included in the vesicles was performed by gel filtration chromatography. We studied the morphology of the obtained liposomal particles by scanning electron microscopy; particle size and zeta potential were determined by dynamic light scattering. The study of the dynamics of sanguinarine release was conducted using the method of dialysis; quantitative analysis of the released sanguinarine from liposomes was performed using reverse-phase HPLC. The cytotoxic activity (CTA) of liposomal preparation against tumor cells of human breast carcinoma MCF-7 line was determined by the MTT assay. The toxicity and biological effects of liposomal sanguinarine on the cultures of Paramecium caudatum Ehrenberg and Tetrahymena pyriformis WH1, as well as the study of the effect of the drug on the complement system, were evaluated using the automated video registration system “BioLaT” (Russia). According to electron microscopy data, the obtained liposomes were spherical nanosized particles (See Fig. 1). The mean size of the obtained liposomal particles with sanguinarine included in their composition, determined using the method of the dynamic light scattering, was 108.5±2.2 nm, and the zeta potential was –34.7±1.4 mV. The effectiveness of sanguinarine inclusion in liposomes was quite high and amounted to 72.8±4.8%. The study of the dynamics of sanguinarine release from liposomes in conditions close to physiological (pH 7.4; 37°C) showed that this process occurs at the highest rate in the first 2 h of incubation. Then, the process is prolonged (release of about 50% sanguinarine after 6 h of incubation, and about 93% after 70 h) (See Fig. 2). Liposomal sanguinarine showed dose-dependent cytotoxic activity against tumor cells of human carcinoma MCF-7 in the micromolar concentration range (Seе Fig. 3). The CTA of liposomal sanguinarine (IC 50 14.5 mM) was slightly lower than the activity of free sanguinarine (IC 50 9.4 mM), which can be explained by the prolonged release of sanguinarine from liposomes into the cell medium, as well as by the specificity of compartmentalization and intracellular release of the drug when it is absorbed by tumor cells by endocytosis. The prolonged release and the property of preferential accumulation of liposomes in tumor tissue can have a positive effect on therapeutic efficacy in the application of liposomal sanguinarine in vivo. The effect of liposomal sanguinarine on the survival of P. caudatum ciliates was dose-dependent (See Fig. 4). The minimum inhibitory concentration of liposomal sanguinarine was 0.49 mM. At concentrations from 0.245 mM and below, the drug did not cause cell death for 2 h; over the next 24 h, the death of the ciliates was neither observed. Thus, liposomal sanguinarine has a pronounced cytotoxic effect on P. caudatum, a representative of the protozoa, which can serve as the basis for the development of antiprotozoal drugs. To identify pathogenic Protozoa species spectrum vulnerable to the action of liposomal sanguinarine, additional research is required. We also assessed the influence of liposomal sanguinarine on the protective blood systems - coagulation and the complement system. The effect of liposomal sanguinarine on thrombus formation in vitro was evaluated in citrate plasma after its recalcification according to the time of the onset of thrombus formation and the resulting clot density (See Fig. 5). The clot size in plasma solutions with the addition of the drug was significantly smaller compared with the control. At the same time, liposomal sanguinarine induces the formation of a clot after 7 min of incubation, whereas in the control the formation of a clot begins only after 14 min of incubation. Thus, under the conditions of this experiment, liposomal sanguinarine had a pronounced stimulating effect on thrombus formation. Stimulation of thrombosis by liposomal sanguinarine can be caused both by direct activation of coagulation enzymes and by the induction of enzymatic reactions of the coagulation system, which can efficiently proceed on the surface of liposomal nanoparticles. The study of the effect of liposomal sanguinarine in a non-toxic concentration of 60 ng/ml on the functional activity of the complement system against T. pyriformis ciliates showed that the half-life of the ciliates as a target of the complement system in the medium containing serum and liposomal sanguinarine (T 50 21.7 min) reduced approximately twice compared with the control (T 50 41.6 min) (See Fig. 6). In the absence of serum in the samples, liposomal sanguinarine at a concentration of 60 ng/ml, on the contrary, had a stimulating effect on T. pyriformis growth - the value of the proliferation coefficient for native cells was 2.1±0.2, and for the treated cells it was 6.4±0.8. The obtained data may indicate the activating effect of liposomal sanguinarine with respect to the assembly of the membrane attack complex of the complement system on the surface of T. pyriformis cells, causing their death. This effect allows to envisage the prospect of using liposomal sanguinarine as an immunostimulating agent. Thus, the pronounced cytotoxic antitumor and antiprotozoal activity, demonstrated in experiments in vitro, makes it possible to consider liposomal sanguinarine as a promising antitumor and antiprotozoal agent. The detected effect of thrombosis stimulation by liposomal sanguinarine seems to be important when selecting the dose of the drug introduced into the bloodstream.

© Copyright 2018 Inderscience Enterprises Ltd. Sanguinarine is a plant alkaloid with relatively low toxicity and high antiangiogenic, antitumour and antiviral potential. In order to increase its bioavailability and effectiveness, sanguinarine liposomes were prepared by a reverse phase evaporation method and characterised. Dynamic light scattering showed mean liposome size of 65 ± 11 nm, zeta-potential equal to -54 ± 1.2 mV, and polydispersity index equal to 0.26. The encapsulation efficiency was 78.6 ± 5.1%. The study on experimental models showed a prolonged sanguinarine release from liposome preparations. Liposomal sanguinarine showed dose-dependent cytotoxic activity in vitro on B16 (murine melanoma) and HeLa (human cervical carcinoma) cell lines. The highest cytotoxicity was observed on B16 cell line (IC50 6.5 μM). HeLa cell line cytotoxicity was relatively lower, equal to 8.03 μM. Compared with free sanguinarine, liposomal sanguinarine may have advantages for in vivo anticancer therapy, due to its lower toxicity and 'passive targeting' as a result of enhanced permeability of tumour vessels.