Transplacental clastogenic and epigenetic effects of gold nanoparticles in mice

The broad application of nanotechnology in medicine, biology, and pharmacology is leading to a dramatic increase of the risk of direct contact of nanoproducts, among which gold nanoparticles (AuNP), with the human organism. The present study aimed at evaluating in vivo the genotoxicity of AuNPs with average size of 40 nm and 100 nm. A single intraperitoneal treatment of adult male and female Swiss mice (strain H) with AuNPs, at a dose of 3.3 mg/kg body weight, had no effect on the frequency of micronucleated polychromatic erythrocytes (MN PCEs) in bone marrow. Conversely, the transplacental treatment with AuNP-100 nm, but not with AuNP-40 nm, applied intraperitoneally at a dose of 3.3 mg/kg to pregnant mice on days 10, 12, 14, and 17 of gestation, resulted in a significant increase in the frequency of MN PCEs in both liver and peripheral blood of mouse fetuses. In parallel, the same treatment with AuNP-100 nm, but not with AuNP-40 nm, produced significant changes in microRNA expression. In particular, out of 1281 mouse microRNAs analyzed, 28 were dys-regulated more than two-fold and to a statistically significant extent in fetus lung, and 5 were up-regulated in fetal liver. Let-7a and miR-183 were significantly up-regulated in both organs. The data presented herein demonstrate for the first time the transplacental size-dependent clastogenic and epigenetic effects of AuNPs in mouse fetus, thus highlighting new aspects concerning the putative genotoxicity of AuNPs during a vulnerable period of life.

A novel glycosylated Cu/Zn-containing superoxide dismutase: production and potential therapeutic effect

The fungal strain Humicola lutea 103 produces a naturally glycosylated Cu/Zn SOD. To improve its yield, the effect of an increased concentration of dissolved oxygen (DO) on growth and enzyme biosynthesis by the producer, cultivated in a 3 l bioreactor, was examined. Exposure to a 20% DO level caused a 1.7-fold increase of SOD activity compared to the DO-uncontrolled culture. Maximum enzyme productivity of SOD was approximately 300 x 10(3) U (kg wet biomass)(-1). The novel enzyme was purified to electrophoretic homogeneity. The presence of Cu and Zn were confirmed by atomic absorption spectrometry. The molecular mass of H. lutea Cu/Zn SOD was calculated to be 31870 Da for the whole molecule and 15936 Da for the structural subunits. The N-terminal sequence revealed a high degree of structural homology with Cu/Zn SOD from other prokaryotic and eukaryotic sources. H. lutea Cu/Zn SOD was used in an in vivo model for the demonstration of its protective effect against myeloid Graffi tumour in hamsters. Comparative studies revealed that the enzyme (i) elongated the latent time for tumour appearance, (ii) inhibited tumour growth in the early stage of tumour progression (73-75% at day 10) and (iii) increased the mean survival time of Graffi-tumour-bearing hamsters. Moreover, the fungal Cu/Zn SOD exhibited a strong protective effect on experimental influenza virus infection in mice. The survival rate increased markedly, the time of survival rose by 5.2 d and the protective index reached 86%. The H. lutea SOD protected mice from mortality more efficiently compared to the selective antiviral drug ribavirin and to commercial bovine SOD. In conclusion, our results suggest that appropriate use of the novel fungal SOD, applied as such or in combination with selective inhibitors, could outline a promising strategy for the treatment of myeloid Graffi tumour and influenza virus infection.

Antioxidant and Antitumor Activities of Novel Quercetin-Loaded Electrospun Cellulose Acetate/Polyethylene Glycol Fibrous Materials

The aim of present study was to obtain novel fibrous materials based on cellulose derivative and polyethylene glycol loaded with natural biologically active compound quercetin by electrospinning. Several methods including scanning electron microscopy (SEM), IR spectroscopy, X-ray diffraction analysis (XRD), water contact angle measurements, differential scanning calorimetry (DSC), and UV-VIS spectroscopy were utilized to characterize the obtained materials. The incorporation of polyethylene glycol in the fibrous material resulted in increased hydrophilicity and burst release of quercetin from the fibers. Quercetin-containing fibrous mats exhibited high antioxidant activity as estimated by DPPH free radical scavenging method. In vitro tests with HeLa tumor cells and SH-4 melanoma skin cells were performed in order to determine the cytotoxicity of the novel materials. It was found that the fibrous CA/PEG/QUE materials exhibited high cytotoxic effect against both cell lines. Therefore, the novel polymeric materials containing quercetin are promising candidates for biomedical and pharmaceutical applications.

Antiproliferative activity of nanofibers containing quaternized chitosan and/or doxorubicin against MCF-7 human breast carcinoma cell line by apoptosis

The antiproliferative activity of electrospun mats of poly(L-lactide- co-D,L-lactide) (coPLA) containing quaternized chitosan (QCh) and/or doxorubicin hydrochloride (DOX) was evaluated against the Michigan Cancer Foundation-7(MCF-7) human breast carcinoma cell line. QCh- and DOX-containing nanofibrous mats possess good antiproliferative activity and decrease considerably the viability of the MCF-7 cells for the different periods of cell incubation as confirmed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Fluorescent microscopy analyses and scanning electron microscopy observations revealed that apoptosis was one of the major mechanisms of MCF-7 cell death induced by the QCh- and DOX-containing mats.

Antitumor activity of glycosylated molluscan hemocyanins via Guerin ascites tumor

As observed in most molluscan hemocyanins, high-mannose type glycans were identified in hemocyanins from Rapana venosa (RvH), Helix lucorum (HlH) and keyhole limpet (Megatura crenulata). In addition, a glycan with a branching structure containing xylose, fucose and terminal methyl hexose was identified in β-HlH. We have examined the immuno-adjuvant properties of hemocyanins, their derivatives and conjugates associated with the cell mediated immunity in experimental tumor-bearing animals with ascites tumor of Guerin. After immunization of the animals with the experimental vaccine preparations, the highest values of splenic lymphocytes were observed in groups immunized with the conjugates RvH-TAg, β-HlH-TAg and KLH-TAg (42.3%; 40.8% and 40.58%, respectively) than with the native hemocyanins (36.5%; 35.1% and 32.4%, respectively). The immunization of rats with the hemocyanins β-HlH, RvH and KLH and their conjugates, prolonged the median survival time of tumor-bearing animals compared with non-immunized animals (39, 33, 31 and 7 days, respectively). Both hemocyanins β-HlH and RvH activate the immune system of the experimental animals and therefore could be a good alternative for KLH. For this reason they could be included into the composition of non-specific anti-tumor vaccines to enhance their effectiveness.

A plant polyphenol-rich extract restores the suppressed functions of phagocytes in influenza virus-infected mice

Influenza infection was induced in white ICR mice by intranasal (i.n.) inoculation of the virus A/Aichi/2/68 (H3N2). The number, migration and phagocyte indices of alveolar and peritoneal macrophages (pMØ) and of blood polymorphonuclear leukocytes (PMNs), as well as the inhibition of the PMN adherence in the presence of a specific antigen were followed for 9 days after infection. The effect of the i.n. application of a polyphenol-rich extract, designated as polyphenolic complex (PC), isolated from the medicinal plant Geranium sanguineum L., on the inspected immune parameters was studied in parallel with the virological parameters of the infection, e.g. rate of mortality, mean survival time (MST), infectious lung virus titre and consolidation of the lungs. It was found that the application of PC induced a continuous 2- to 2.5-fold rise in the number of both peritoneal and alveolar macrophages (aMØ) in the infected and healthy controls. The migration of both peritoneal and aMØ increased 1.5- to 2-fold in the group of infected PC-treated animals and four to fivefold in the control group, the maximum being on day 9. PC stimulated phagocyte activities of blood PMNs in both infected and healthy mice. The leukocyte adherence inhibition (LAI) index decreased in the infected and PC-treated animals. The restoration of the suppressed functions of phagocytes in influenza virus-infected mice (VIM) was consistent with a prolongation of MST and reduction in mortality rate, infectious virus titre and lung consolidation. The immunoenhancing properties of PC apparently contribute to the overall protective effect of the plant preparation in the lethal murine experimental influenza A/Aichi infection.

Еlectrospun сellulose acetate membranes decorated with curcumin-PVP particles: preparation, antibacterial and antitumor activities

Curcumin (Curc) exhibits anti-inflammatory, antibacterial and antitumor activity. However, its clinical application is limited by its poor bioavailability related to its extremely low water solubility. Novel materials allowing enhanced release of Curc in aqueous medium were obtained. The new materials consisted of electrospun fibers from cellulose acetate (CA) (mean fiber diameter ca. 780 nm ± 110 nm) with electrosprayed Curc/polyvinylpyrrolidone (Curc/PVP) particles. Scanning electron microscopy (SEM) showed that separated and evenly distributed particles of Curc/PVP were deposited on the surface of the mats and on the inner layers of the mat. X-ray diffraction studies showed that Curc was in amorphous state. In vitro studies demonstrated that Curc release was facilitated from Curc/PVP-on-CA mats (ca. 78% for 24 h) compared with the materials in which Curc was incorporated in CA fibers (17% for 24 h). Moreover, the curcumin-containing materials exhibited antibacterial activity against Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative bacteria Escherichia coli (E. coli). Curc/PVP-on-CA fibrous mats exhibited high in vitro cytotoxicity towards HeLa tumor cells. Therefore, the obtained materials are promising for antibacterial wound dressing applications as well as for application in local treatment of cervical tumors.

Effect of a plant polyphenol-rich extract on the lung protease activities of influenza-virus-infected mice

Influenza infection was induced in white mice by intranasal inoculation of the virus A/Aichi/2/68 (H3N2). The lung protease and the protease-inhibitory activities were followed for 9 days after infection. The intranasal application of a polyphenol-rich extract (PC) isolated from Geranium sanguineum L. induced a continuous rise in the anti-protease activity but did not cause substantial changes in the lung protease activity of healthy mice. Influenza virus infection triggered a slight reduction in protease activity in the lungs at 5 and 48 h post infection (p.i.) and a marked increase at 24 h and 6 day p.i.. Protease inhibition in the lungs was reduced at 24 and 48 h p.i. and an increase was observed at 5 h and 6 and 9 days p.i.. PC treatment brought both activities to normal levels. The restoration of the examined parameters was consistent with a prolongation of mean survival time and reduction of mortality rate, infectious virus titre and lung consolidation. PC reinstated superoxide production by alveolar macrophages and increased their number in virus-infected mice. The favourable effect on the protease and the protease-inhibitory activities in the lungs of influenza-virus-infected mice apparently contributes to the overall protective effect of PC in the murine experimental influenza A/Aichi infection. The antiviral effect of the individual constituents was evaluated.

Electrospun materials from polylactide and Schiff base derivative of Jeffamine ED® and 8-hydroxyquinoline-2-carboxaldehyde and its complex with Cu2+: Preparation, antioxidant and antitumor activities

Novel fibrous materials from polylactide (PLA) and Schiff base from Jeffamine ED® and 8-hydroxyquinoline-2-carboxaldehyde (Jeff-8Q) or its complex with Cu²⁺ (Jeff-8Q.Cu²⁺) were successfully prepared by using one-pot electrospinning or electrospinning combined with dip-coating. These approaches enabled the fabrication of materials of diverse design: non-woven textile in which Jeff-8Q or Jeff-8Q.Cu²⁺ was predominantly in the fibers' bulk (type "in") or was deposited as a thin film on the surface of the fibers (type "on"). The morphology of the mats and chemical composition of their surface were analyzed by means of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The coordination of Cu²⁺ ions in Jeff-8Q.Cu²⁺/inPLA and Jeff-8Q.Cu²⁺/onPLA mats was examined by electron paramagnetic resonance (EPR) spectroscopy. It was found that the in vitro release of Jeff-8Q (Jeff-8Q.Cu²⁺) from the type "on" mats was more rapid than that of the type "in" mats. Enhancement of the antioxidant activity of the Jeff-8Q.Cu²⁺-containing fibrous mats as compared to mats containing Jeff-8Q was observed. In contrast to the neat PLA mat, the Jeff-8Q- and Jeff-8Q.Cu²⁺-containing mats (both type "in" and "on") displayed high in vitro antitumor activity against human cervical HeLa cells. The obtained materials are promising for use in local tumor treatment.

Nanoparticles based on complex of berberine chloride and polymethacrylic or polyacrylic acid with antioxidant and in vitro antitumor activities

Berberine chloride (Brb) is a natural isoquinoline quaternary alkaloid that displayed a set of beneficial biological properties such as antioxidant, antimicrobial, antitumor, anti-inflammatory, and antiviral. Brb is poorly soluble in water and body fluids and its intestinal absorption is very low, which predetermine its low bioavailability. Polymeric nanoparticles seem to be a good platform to overcome these drawbacks. In this study, for the first time, stable aqueous dispersions of nanoparticles (NPs) based on complexes of Brb and poly(methacrylic acid) (PMA) or poly(acrylic acid) (PAA), were successfully prepared by mixing their dilute aqueous solutions as evidenced by the performed dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses. It was found that the mean diameter and zeta potential of NPs depended on the Brb molar fraction. In the case of Brb/PMA and Brb/PAA NPs the encapsulation efficiency was observed to approach a maximum value of 58.9 ± 0.5% and of 78.4 ± 0.9%, respectively, at values of Brb molar fraction at which maximum amount of complexes was obtained. The performed differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses revealed that Brb incorporated in the NPs was in the amorphous state. The Brb release profile was pH-dependent. The Brb-containing NPs displayed good antioxidant capacity close to that of free Brb. In vitro cell viability studies demonstrated that the Brb/PMA (PAA) NPs exerted a higher cytotoxicity against HeLa tumor cell than non-tumor BALB/c 3T3 mouse fibroblast cells. Thus, the obtained NPs are promising candidates in the drug delivery systems in the treatment of cervical tumors.

Antiproliferative and antitumour activity of saponins from Astragalus glycyphyllos on myeloid Graffi tumour

ETHNOPHARMACOLOGICAL RELEVANCE

Astragalus glycyphyllos L. has been extensively used in Bulgarian folk medicine as an antihypertensive, diuretic, anti-inflammatory, anti-tumour, in cases of cardiac insufficiency, renal inflammation, calculosis, etc. AIM OF THE STUDY: To evaluate the possible in vitro/in vivo anti-proliferative/anti-tumour activity of a purified saponins' mixture (PSM) obtained from the plant.

MATERIALS AND METHODS

Viability and proliferative activity of the Graffi myeloid tumour cells was assessed by MTT test. The morphological alterations were visualized and analysed by fluorescent microscopy after intravital double staining. An in vivo model of Graffi tumour bearing hamsters was used to examine the influence of PSM on transplantability, tumour growth, survival and mortality as well as to observe pathomorphological changes.

RESULTS

Graffi tumour cells were sensitive to purified saponins' mixture after 24 and 48 h treatment. The treatment induced a statistically significant decrease of the viability/proliferation of the Graffi tumour cells. These effects were concentration- and time-dependent. Fluorescent microscopy studies showed that these antiproliferative effects were connected to the induction of apoptosis. The in vivo study showed the presence of a stromal component, single mononuclear cells in the stroma. Multiple incorrect mitotic figures were observed in the tumour tissue from the control group. Well-formed stroma with accumulation of mononuclear cells and mitotic cells were found in the group, treated with PSM. The tumour weight was decreased in the group, treated with PMS.

CONCLUSION

The results indicate that PSM exhibited in vitro/in vivo antiproliferative/anti-tumour effects.

Curcumin-PVP Loaded Electrospun Membranes with Conferred Antibacterial and Antitumoral Activities

Electrospun membranes containing curcumin were prepared from poly(L-co-D,L-lactic) acid and polyvinylpyrrolidone. The effect of curcumin concentration on the solution viscosity and the morphology of fiber was studied. Curcumin solubility in aqueous solutions was enhanced by the formation of curcumin/polyvinylpyrrolidone water-soluble complex. Curcumin physico-chemical and therapeutic properties within the membranes were preserved upon UV-Vis light irradiation, as a part of the membranes sterilization. The biomaterials showed antibacterial activity against pathogenic microorganisms such as Staphylococcus aureus and Candida albicans. In-vitro experiments against HeLa and Graffi tumor cells and white blood cells (peritoneal macrophages and spleen lymphocytes) revealed potential biomedical application of the membranes.

8-Hydroxyquinoline-5-Sulfonic Acid-Containing Poly(Vinyl Alcohol)/Chitosan Electrospun Materials and Their Cu2+ and Fe3+ Complexes: Preparation, Antibacterial, Antifungal and Antitumor Activities

Novel poly(vinyl alcohol) (PVA)/chitosan (Ch)-based fibrous materials containing an ionizable model drug, 8-hydroxyquinoline-5-sulfonic acid (SQ), were successfully fabricated by electrospinning. Complexes between the components of the crosslinked PVA/Ch/SQ mats and Cu2+ and Fe3+ ions were formed. The coordination of these ions in the mats was examined by electron paramagnetic resonance spectroscopy (EPR). The microbiological screening against S. aureus and C. albicans revealed that both the incorporation of SQ in the mats and the complexation with Cu2+ and Fe3+ imparted to these materials antibacterial and antifungal activities. Moreover, the SQ-containing mats and their complexes displayed good cytotoxicity against human cervical HeLa tumor cells. The most prominent was the cytotoxicity of the Cu2+ complex of the mats. The combined antibacterial, antifungal and in vitro antitumor activities render these novel materials promising candidates for wound dressing applications and for application in the local treatment of cervical tumors.

Pegylated Curcumin Derivative: Water-Soluble Conjugates with Antitumor and Antibacterial Activity

During the past years, the synthesis of polymer prodrug structures, based on natural phytochemical compounds with a great range of valuable biological properties, has become a promising solution in cancer prevention, imaging, and detection. Curcumin (Curc) remains one of the most studied natural products, due to the impressive palette of biological properties and the possibility to be easily loaded in various micro- and nanostructures and chemically modified. In this study, pegylated curcumin derivatives were prepared by a direct esterification reaction between poly(ethylene glycol)diacid (PEG of 600 g/mol molar mass, PEG₆₀₀) and Curc in the presence of N,N'-dicyclohexylcarbodiimide (PEG₆₀₀-Curc). The successful reaction resulted in a water-soluble stable product that was characterized by infrared spectroscopy (Fourier transform infrared (FT-IR)) and proton (¹H) and carbon (¹³C) NMR. The effect of the pH values of buffer solutions on PEG₆₀₀-Curc spectral properties (absorption and photoluminescence) was investigated by UV-vis and fluorescence spectrophotometry. Based on the biological tests, it was confirmed that PEG₆₀₀-Curc exhibits cytotoxic activity against Graffi cell lines, as a function of the Curc concentration in the conjugate and the incubation time. PEG₆₀₀-Curc antibacterial activity was validated in microbiological tests against pathogenic microorganisms such as Staphylococcus aureus. Most importantly, despite the covalent attachment of Curc to PEG and the slight reduction in the therapeutic index of the conjugate, both the anticancer and antimicrobial activities remain the highest reported, thus opening the gate for further, more clinically oriented studies.

Effect of Cu/Zn-superoxide dismutase from the fungal strain Humicola lutea 103 on antioxidant defense of Graffi tumor-bearing hamsters

A novel Cu/Zn-containing superoxide dismutase (SOD) was isolated from the fungal strain Humicola lutea 103. Previously, a protective effect of this enzyme (HLSOD) against tumor growth and also superoxide production in Graffi tumor-bearing hamsters (TBH) were established. The aim of the present study was to investigate the effect of HLSOD on the activity of endogenous SOD and catalase in the cells from TBH during tumor progression. Our results point out that transplantation of Graffi tumor causes a significant decrease in SOD activity in the cells from liver of the hosts (from 35 to 59% compared to the control). In the tumor cells relatively low levels of SOD (about 7 U mg protein(-1)) were found, and Cu/ZnSOD was the main isoenzyme in total SOD activity. Tumor growth resulted in a reduction of catalase activity, which correlated with the process of tumor progression. A single dose (65 U) treatment with HLSOD caused an increase in endogenous SOD and catalase activity in healthy animals and resulted in restoration of the antioxidant ability in liver cells of the hosts at the early stage of tumor progression. The results show the possible participation of HLSOD in the host oxidant-antioxidant balance, which is probably one of the factors of its immunoprotective action established earlier.

Studies on the interactions of immunostimulated macrophages andYersinia enterocoliticaO:8

Immunological and electron microscopy investigations of the phagocytic and killing activities of peritoneal macrophages from rats and mice against Yersinia enterocolitica serotype O:8 cells were performed. The effect of in vivo application of cytoplasmic membranes (CM) from the stable Escherichia coli WF+ L-form on macrophage activity was also studied. It was established that rat macrophages more actively phagocytosed the plasmidless pYV(-) Y. enterocolitica cells, compared to the plasmid-bearing pYV(+) Y. enterocolitica cells. The killing ability against both variants of the Y. enterocolitica strain was significantly enhanced in macrophages from CM-treated rats after 2 h, 4 h, and 24 h incubation. The CM treatment enhanced the phagocytic activity of the macrophages. The in vitro interaction of normal and immunostimulated rat macrophages with both pYV(+) and pYV(-) variants of Y. enterocolitica did not lead to any additional apoptotic and necrotic changes in macrophages compared to control macrophages, which were cultivated without Y. enterocolitica. Electron-microscopic investigation showed that mouse macrophages eliminated Y. enterocolitica pYV(+) cells in vivo after 24 h. No engulfed or digested bacterial cells were observed. Activation of cell surfaces and vacuolization of macrophage cytoplasm, both of CM-treated non-infected and infected mice, were observed. The experimental results showed that Y. enterocolitica pYV(+) cells could be eliminated by peritoneal macrophages.Key words: Yersinia enterocolitica, immunostimulation, electron microscopy, bacterial L-forms, macrophages.