Combination of selol nanocapsules and magnetic hyperthermia hinders breast tumor growth in aged mice after a short-time treatment

Short time treatment with reduced dosages of selol-loaded PLGA nanocapsules (NcSel) combined with magnetic hyperthermia (MHT) is evaluated in aged Erhlich tumor-bearing mice. Clinical, hematological, biochemical, genotoxic and histopathological parameters are assessed during 7 d treatment with NcSel and MHT, separately or combined. The time evolution of the tumor volume is successfully modeled using the logistic mathematical model. The combined therapy comprising NcSel and MHT is able to hinder primary tumor growth and a case of complete tumor remission is recorded. Moreover, no metastasis was diagnosed and the adverse effects are negligible. NcSel plus MHT may represent an effective and safe alternative to cancer control in aged patients. Future clinical trials are encouraged.

Magnetic studies of polylactic-co-glicolic acid nanocapsules loaded with selol and γ-Fe2O3 nanoparticles

The as-prepared (MSE-NCs sample) and lyophilized (LMSE-NCs sample) polylactic-co-glicolic acid (PLGA) nanocapsules loaded with maghemite (γ-Fe2O3) nanoparticles and selol (Se-based anticancer drug) were investigated by means of dc magnetization, ac susceptibility and electron spin resonance (ESR) measurements over the temperature range of 4-300 K. The magnetic data of the as-synthesized nanocapsules containing only maghemite nanoparticles (M-NCs sample) or selol (SE-NCs sample) were also collected for comparison. The magnetic nanocapsules reveal perfect superparamagnetic (SPM) behavior only around room temperature; at temperatures lower than 200 K the SPM scaling is not observed and all samples behave as interacting superparamagnetic (ISPM) materials. The evolution from the ISPM to the SPM regime is marked by a steady decrease in the hysteretic properties of all samples, with the temperature dependence of the coercivity decreasing slower than the T1/2 behavior predicted for non-interacting SPM particles. The SPM character of the samples is also confirmed by the occurrence of a maximum in the temperature dependence of both real χ'(T) and imaginary χ''(T) components of the ac magnetic susceptibility, which shifts towards higher temperatures with increasing frequency. Moreover, upon decreasing the temperature the ESR signal shifts to lower fields and gradually broadens, following closely the predictions for the ESR of SPM particles. Additionally, an unusual giant diamagnetic response is observed at low temperatures. The ZFC magnetization is found to reverse its direction and becomes diamagnetic, whereas the FC branch remains positive. Even when compared with usual superconductors, the order of the diamagnetic susceptibility for the lyophilized sample (-10-2 emu g-1 Oe-1) is quite considerable. The nanocapsules herein reported and the presented analysis of their magnetic properties we envisage can support the engineering of magnetic nanocapsules for applications in magnetic drug delivery systems and as magnetic hyperthermia inductors in antitumor therapy.

Preliminary study on Se-enriched Lentinula edodes mycelium as a proposal of new feed additive in selenium deficiency

The presence of selenium in European soil is low and this causes its deficiency in livestock and, in consequence, in humans. This study aimed to obtain Lentinula (L.) edodes mycelium with the maximum content of selenium. This species was used for experiment based on its documented medicinal properties. Calves were fed with selenium-enriched L. edodes mycelium, and serum selenium concentration, average daily weight gains and selected immune parameters were estimated. The selenium-enriched mushroom was found to be safe based on cytotoxicity tests (MTT and LDH tests) and for this reason it was used for further experiments. The mean quantity of selenium in the serum of calves fed with selenium-enriched L. edodes mycelium was significantly higher than that of control calves. Additionally, the calves fed with selenium-enriched L. edodes mycelium had higher body weight gains than those of control calves. White blood cell counts and subpopulations of lymphocytes in the experimental and control calves were within the reference range. The administration of L. edodes enriched with selenium had a beneficial effect on state of health of the calves.

Correction to: Lentinula edodes as a Source of Bioelements Released Into Artificial Digestive Juices and Potential Anti-inflammatory Material

The original version of this article unfortunately contained a mistake.

Lentinula edodes as a Source of Bioelements Released into Artificial Digestive Juices and Potential Anti-inflammatory Material

Lentinula edodes (shiitake), an edible and medicinal mushroom, was chosen for this study with the aim of evaluating the possibility of release of bioelements into artificial digestive juices and analyzing the anti-inflammatory properties. The extracts were prepared from fruiting bodies and biomass enriched with copper (Cu), zinc (Zn), and selenium (Se). The content of bioelements was analyzed by total reflection X-ray fluorescence method. Relatively low content of elements was observed in the fruiting bodies: Cu-1.6, Zn-7.6, and Se-0.12 mg/100 g d.w. compared to mycelial cultures. The anti-inflammatory properties were evaluated in RAW 264.7 cells. Based on the levels of cyclooxygenase 2 protein, nuclear factor erythroid 2-related factor 2, and peroxisome proliferator-activated receptor γ determined using Western blot technique, it was found that the addition of bioelements enhanced the anti-inflammatory properties of mycelium. This indicates that L. edodes cultured on a suitable medium may be used as a potential component of anti-inflammatory products.

Selol (Se IV) modulates adhesive molecules in control and TNF-α-stimulated HMEC-1 cells

Selol, an organic selenitetrigliceride formulation containing selenium at +4 oxidation level, has been suggested as anticancer drug. One of the causes of several diseases including cancer may be inflammation. This study aimed at determining the activity of Selol via measuring its effect on reactive oxygen species (ROS) generation, nuclear factor kappa B (NF-κB) activation, intercellular cell adhesion molecules-1 (ICAM-1), vascular cell adhesive molecule-1 (VCAM-1), and plateled-endothelial cell adhesive molecule-1 (PECAM-1) levels on control and on tumor necrosis factor-α (TNF-α)-stimulated human microvascular endothelial cells (HMEC-1). Cells were treated either with Selol 5% (4 or 8 μgSe/mL) or TNF-α (10 ng/mL) alone or with Selol concomitant with TNF-α. Selol treatment resulted in ROS generation, activation of NF-κB, downregulation of PECAM-1, VCAM-1 and slight upregulation ICAM-1 expression on the cell surface. TNF-α treatment reflected in sharp NF-κB activation, upregulation of both ICAM-1 and VCAM-1 in parallel with the downregulation of PECAM-1 expression on cell surface. Exposure to both compounds upregulated ICAM-1 and VCAM-1, downregulated PECAM-1 level on cell surface in parallel with no changes in level of NF-κB activation as compared with effects mediated by TNF-α alone. These results points to new look at Selol action since it shows a pro-inflammatory activity in parallel with effects on CAMs expression on the cell surface of human microvascular endothelial cells. However, since Selol enhances CAMs expression level when is present concomitantly with TNF-α this fact might suggest that selenium present in the condition of inflammation will make it worse.

Effects of Selol 5% supplementation on tissue antioxidant enzyme levels and peroxidation marker in healthy mice

BACKGROUND

Selenium (Se) is an essential micronutrient for animals and humans used in the prevention or treatment of cancer. Selol is a mixture of selenitetriglycerides, containing Se(IV). It does not exhibit mutagenic activity and is less toxic than inorganic sodium selenite containing Se(IV). The antioxidant properties of the Selol were demonstrated using the blood of healthy animals. The aim of the study was to evaluate Selol as a Se supplement by determining the effect of its administration on the Se level and the antioxidant status in the tissues.

METHODS

We examined the effect of long-term (28-day) Selol 5% supplementation on the activity of antioxidant enzymes, including the main selenoenzymes in healthy mice organs, such as liver, brain, lungs, and testis. Enzyme activities of the tissue homogenates and the concentration of malondialdehyde (MDA) as a biomarker of oxidative stress were measured using spectrophotometric methods. The selenium concentrations in the tissues were determined by inductively coupled plasma mass spectrometer (ICP-MS) as well.

RESULTS

A significant increase in glutathione peroxidase, thioredoxin reductase, and glutathione S-transferase activity as well as the MDA concentration was observed in most of the studied tissues during the Selol 5% supplementation.

CONCLUSIONS

Long-term supplementation with the new Se(IV) compound - Selol 5% significantly affects the activity of antioxidant enzymes and the redox state in healthy mice organs. In the healthy population Selol 5% seems to be a promising new antioxidant compound.

Decoration of a Poly(methyl vinyl ether-co-maleic anhydride)-Shelled Selol Nanocapsule with Folic Acid Increases Its Activity Against Different Cancer Cell Lines In Vitro

Due to the low therapeutic index of different chemotherapeutic drugs used for cancer treatment, the development of new anticancer drugs remains an intense field of research. A recently developed mixture of selenitetriacylglycerides, selol, was shown to be active against different cancer cells in vitro. As this compound is highly hydrophobic, it was encapsulated, in a previous study, into poly(methyl vinyl ether-co-maleic anhydride)-shelled nanocapsules in order to improve its dispersibility in aqueous media. Following this line of research, the present report aimed at enhancing the In Vitro activity of the selol nanocapsules against cancerous cells by decorating their surface with folic acid. It is known that several cancer cells overexpress folate receptors. Stable folic acid-decorated selol nanocapsules (SNP-FA) were obtained, which showed to be spherical, with a hydro-dynamic diameter of 364 nm, and zeta potential of -24 mV. In comparison to non-decorated selol nanocapsules, SNP-FA presented higher activity against 4T1, MCF-7 and HeLa cells. Moreover, the decoration of the nanocapsules did not alter their toxicity towards fibroblasts, NIH-3T3 cells. These results show that the decoration with folic acid increased the toxicity of selol nanocapsules to cancer cells. These nanocapsules, besides enabling to disperse selol in an aqueous medium, increased the toxicity of this drug In Vitro, and may be useful to treat cancer in vivo, potentially increasing the specificity of selol towards cancer cells.

Nanocapsules for the co-delivery of selol and doxorubicin to breast adenocarcinoma 4T1 cells in vitro

Nanocapsules (NCS-DOX) with an oily core of selol and a shell of poly(methyl vinyl ether-co-maleic anhydride) covalently conjugated to doxorubicin were developed. These nanocapsules are spherical, with an average hydrodynamic diameter of about 170 nm, and with negative zeta potential. NCS-DOX effectively co-delivered the selol and the doxorubicin into 4T1 cells and changed the intracellular distribution of DOX from the nuclei to the mitochondria. Moreover, a significantly increased cytotoxicity against 4T1 cells was observed, which is suggestive of additive or synergic effect of selol and doxorubicin. In conclusion, PVM/MA nanocapsules are suitable platforms to co-deliver drugs into cancer cells.

Speciation of Selenium in Selenium-Enriched Sunflower Oil by High-Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry/Electrospray-Orbitrap Tandem Mass Spectrometry

The reaction of sunflower oil with selenite produces a complex mixture of selenitriglycerides with antioxidant and anticancer properties. To obtain insight into the identity and characteristics of the species formed, an analytical approach based on the combination of high-performance liquid chromatography (HPLC) with (78)Se-specific selenium detection by inductively coupled plasma mass spectrometry (ICP MS) and high-resolution (100 000), high mass accuracy (<1 ppm) molecule-specific detection by electrospray-Orbitrap MS(3) was developed. For the first time, a non-aqueous mobile phase gradient was used in reversed-phase HPLC-ICP MS for the separation of a complex mixture of selenospecies and a mathematical correction of the background signal was developed. The identical chromatographic conditions served for the sample introduction into electrospray MS. Two types of samples were analyzed: sunflower oil dissolved in isopropanol and methanol extract of the oil containing 65% selenium. HPLC-ICP MS showed 14 peaks, 11 of which could also be detected in the methanol extract. Isotopic patterns corresponding to molecules with one or two selenium atoms could be attributed by Orbitrap MS at the retention times corresponding to the HPLC-ICP MS peak apexes. Structural data for these species were acquired by MS(2) and MS(3) fragmentation of protonated or sodiated ions using high-energy collisional dissociation (HCD). A total of 11 selenium-containing triglycerol derivatives resulting from the oxidation of one or two double bonds of linoleic acid and analogous derivatives of glycerol-mixed linoleate(s)/oleinate(s) have been identified for the first time. The presence of these species was confirmed by the targeted analysis in the total oil isopropanol solution. Their identification corroborated the predicted elution order in reversed-phase chromatography: LLL (glycerol trilinoleate), LLO (glycerol dilinoleate-oleinate), LOO (glycerol linoleate-dioleinate), OOO (glycerol trioleinate), of which the extrapolation allowed for the prediction of the identity [glycerol dioleinate-stearate (OOS) and glycerol oleinate-distearate (OSS)] of the nonpolar species detected by ICP MS in the oil but not detected by electrospray MS.

The Comparison of MTT and CVS Assays for the Assessment of Anticancer Agent Interactions

Multiple in vitro tests are widely applied to assess the anticancer activity of new compounds, including their combinations and interactions with other drugs. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay is one of the most commonly used assays to assess the efficacy and interactions of anticancer agents. However, it can be significantly influenced by compounds that modify cell metabolism and reaction conditions. Therefore, several assays are sometimes used to screen for potential anticancer drugs. However, the majority of drug interactions are evaluated only with this single method. The aim of our studies was to verify whether the choice of an assay has an impact on determining the type of interaction and to identify the source of discrepancies. We compared the accuracy of MTT and CVS (crystal violet staining) assays in the interaction of two compounds characterized by similar anticancer activity: isothiocyanates (ITCs) and Selol. Confocal microscopy studies were carried out to assess the influence of these compounds on the reactive oxygen species (ROS) level, mitochondrial membrane potential, dead-to-live cell ratio and MTT-tetrazolium salt reduction rate. The MTT assay was less reliable than CVS. The MTT test of Selol and 2-oxoheptyl ITC, which affected the ROS level and MTT reduction rate, gave false negative (2-oxoheptyl ITC) or false positive (Selol) results. As a consequence, the MTT assay identified an antagonistic interaction between Selol and ITC, while the metabolism-independent CVS test identified an additive or synergistic interaction. In this paper, we show for the first time that the test assay may change the interpretation of the compound interaction. Therefore, the test method should be chosen with caution, considering the mechanism of action of the compound.

Antitumor activity and systemic effects of PVM/MA-shelled selol nanocapsules in lung adenocarcinoma-bearing mice

Selol is a semi-synthetic compound containing selenite that is effective against cancerous cells and safer for clinical applications in comparison with other inorganic forms of selenite. Recently, we have developed a formulation of poly(methyl vinyl ether-co-maleic anhydride)-shelled selol nanocapsules (SPN), which reduced the proliferative activity of lung adenocarcinoma cells and presented little deleterious effects on normal cells in in vitro studies. In this study, we report on the antitumor activity and systemic effects induced by this formulation in chemically induced lung adenocarcinoma-bearing mice. The in vivo antitumor activity of the SPN was verified by macroscopic quantification, immunohistochemistry and morphological analyses. Toxicity analyses were performed by evaluations of the kidney, liver, and spleen; analyses of hemogram and plasma levels of alanine aminotransferase, aspartate transaminase, urea, and creatinine; and DNA fragmentation and cell cycle activity of the bone marrow cells. Furthermore, we investigated the potential of the SPN formulation to cause hemolysis, activate the complement system, provoke an inflammatory response and change the conformation of the plasma proteins. Our results showed that the SPN reduced the area of the surface tumor nodules but not the total number of tumor nodules. The biochemical and hematological findings were suggestive of the low systemic toxicity of the SPN formulation. The surface properties of the selol nanocapsules point to characteristics that are consistent with the treatment of the tumors in vivo: low hemolytic activity, weak inflammatory reaction with no activation of the complement system, and mild or absent conformational changes of the plasma proteins. In conclusion, this report suggests that the SPN formulation investigated herein exhibits anti-tumoral effects against lung adenocarcinoma in vivo and is associated with low systemic toxicity and high biocompatibility.

PVM/MA-shelled selol nanocapsules promote cell cycle arrest in A549 lung adenocarcinoma cells

BACKGROUND

Selol is an oily mixture of selenitetriacylglycerides that was obtained as a semi-synthetic compound containing selenite. Selol is effective against cancerous cells and less toxic to normal cells compared with inorganic forms of selenite. However, Selol's hydrophobicity hinders its administration in vivo. Therefore, the present study aimed to produce a formulation of Selol nanocapsules (SPN) and to test its effectiveness against pulmonary adenocarcinoma cells (A549).

RESULTS

Nanocapsules were produced through an interfacial nanoprecipitation method. The polymer shell was composed of poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA) copolymer. The obtained nanocapsules were monodisperse and stable. Both free Selol (S) and SPN reduced the viability of A549 cells, whereas S induced a greater reduction in non-tumor cell viability than SPN. The suppressor effect of SPN was primarily associated to the G2/M arrest of the cell cycle, as was corroborated by the down-regulations of the CCNB1 and CDC25C genes. Apoptosis and necrosis were induced by Selol in a discrete percentage of A549 cells. SPN also increased the production of reactive oxygen species, leading to oxidative cellular damage and to the overexpression of the GPX1, CYP1A1, BAX and BCL2 genes.

CONCLUSIONS

This study presents a stable formulation of PVM/MA-shelled Selol nanocapsules and provides the first demonstration that Selol promotes G2/M arrest in cancerous cells.

Selenitetriglycerides-Redox-active agents

BACKGROUND

Human prostate cancer (hPCa) is the most commonly diagnosed cancer in elderly men and is the second leading cause of male cancer death. Data from epidemiological, eco-environmental, nutritional prevention and clinical trials suggest that selenium Se(IV) can prevent prostate cancer. Selol, a new organic semisynthetic derivative of Se(IV), is a mixture of selenitetriglycerides. This mixture is non-toxic and non-mutagenic, and after po treatment - 56-times less toxic (in mice) than sodium selenite. It exhibits strong anti-cancer activity in vitro in many cancer cell lines and can overcome the cell resistance to doxorubicin. Selol seems a promising compound for prostate cancer therapy.

MATERIALS AND METHODS

The aim of the present study is the evaluation of Selol's influence on intracellular redox state (Eh) of prostatic tumors and the liver in androgen-dependent hPCa-bearing mice, and extracellular redox state in serum of these mice.

RESULTS AND CONCLUSIONS

The anticancer activity of Selol involves perturbation of the redox regulation in the androgen dependent hPCa (LNCaP) cells, but not in healthy cells. After Selol treatment, intracellular Eh has increased in tumors from -223 mV to -175 mV, while in serum it has decreased (-82 mV vs -113 mV). It shows significant changes Eh in the extra- and intracellular environment. The difference decreases from 141 mV to 62 mV. The changes suggest that a tumor cell was probably directed toward apoptosis. This is exemplified in a significant decrease in cancer tumor mass by approx. 17% after the three weeks of Selol administration.

Effects of Selol 5% supplementation on the activity or concentration of antioxidants and malondialdehyde level in the blood of healthy mice

BACKGROUND

Selol is a novel organoselenium Se(IV) compound. It reveals lower potential of toxicity than sodium selenite and does not exhibit mutagenic activity. Its antioxidant and anticancer properties including overcoming cancer cell resistance to standard therapy of the drug were proven. This is the first publication describing the influence of Selol 5% on the activity of blood antioxidant status in vivo.

MATERIALS AND METHODS

We investigated the influence of Selol 5% short-term (24h) and long-term (28 days) administration on the activity of antioxidant enzymes, including the main selenoenzymes, in healthy mice plasma and erythrocytes. Plasma oxygen radical absorbance capacity value (ORAC) and the concentration of malonyldialdehyde (MDA) in plasma as a biomarker of oxidative stress as well as the value of selenium (Se) concentration in erythrocytes were shown.

RESULTS

A significant increase of the selenium dependent glutathione peroxidase (Se-GSHPx) activity in plasma and erythrocytes, plasma selenoprotein P concentration, ORAC values, and Se concentration were observed during long-term supplementation as well as after Selol 5% single-dose administration, with two distinct increases of activity a few hours after the beginning of the experiment and before its end. We found a decreased thioredoxin reductase (THRR) activity and an increased MDA level during Selol 5% long-term supplementation. Glutathione S-transferase activity (GST) remained unchanged.

CONCLUSION

Selol 5% supplementation in vivo affects the selenoenzymes activities as well as the antioxidant status of plasma and erythrocytes. Selol 5% is an inhibitor of thioredoxin reductase activity, which can be important in anticancer therapy.

The influence of Selol on the expression of oxidative stress genes in normal and malignant prostate cells

Selol is a mixture of selenitriglycerides, obtained by the chemical modification of sunflower oil, which contain selenium at the +4 oxidation state. The aim of the present study was to describe the changes in the expression of genes related to oxidative stress caused by Selol in prostate cells: both normal (PNT1A) and malignant (LNCaP). The changes in gene expression in PNT1A and LNCaP cell lines under the influence of Selol were measured using a 96-well RT(2) Profiler ™PCR Array: Human Oxidative Stress and Antioxidant Defense, which arrayed 84 genes functionally involved in the cellular oxidative stress response. Based on the obtained data, LNCaP cells exhibited a significantly lower potential for antioxidant defence when compared to PNT1A cells. The response of the malignant LNCaP cells to exposure to Selol was significantly different from that of the normal PNT1A cells, especially after 48 h of incubation. In the case of LNCaP cells, Selol causes down-regulation of the expression of many vital genes. Under in vitro conditions, the efficacy of Selol slightly changes with increasing concentration, but significantly increases when the incubation time is lengthened.

Co-nanoencapsulation of magnetic nanoparticles and selol for breast tumor treatment: in vitro evaluation of cytotoxicity and magnetohyperthermia efficacy

Antitumor activities have been described in selol, a hydrophobic mixture of molecules containing selenium in their structure, and also in maghemite magnetic nanoparticles (MNPs). Both selol and MNPs were co-encapsulated within poly(lactic-co-glycolic acid) (PLGA) nanocapsules for therapeutic purposes. The PLGA-nanocapsules loaded with MNPs and selol were labeled MSE-NC and characterized by transmission and scanning electron microscopy, electrophoretic mobility, photon correlation spectroscopy, presenting a monodisperse profile, and positive charge. The antitumor effect of MSE-NC was evaluated using normal (MCF-10A) and neoplastic (4T1 and MCF-7) breast cell lines. Nanocapsules containing only MNPs or selol were used as control. MTT assay showed that the cytotoxicity induced by MSE-NC was dose and time dependent. Normal cells were less affected than tumor cells. Cell death occurred mainly by apoptosis. Further exposure of MSE-NC treated neoplastic breast cells to an alternating magnetic field increased the antitumor effect of MSE-NC. It was concluded that selol-loaded magnetic PLGA-nanocapsules (MSE-NC) represent an effective magnetic material platform to promote magnetohyperthermia and thus a potential system for antitumor therapy.

Selenitetriglicerydes affect CYP1A1 and QR activity by involvement of reactive oxygen species and Nrf2 transcription factor

Selenitetriglycerides are a group of compounds that contain selenium (Se) (IV). In this paper, we present the results of examinations of three structurally-related selenitetriglicerydes that contain various Se concentrations: 2%, 5% and 7% Selol. The present study concentrates on the effect of Selol on phase 1 and 2 enzyme activity and the implications of free radicals and the nuclear erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway in the activity of this compound. The cytotoxic and cytostatic activities of the three kinds of Selol were evaluated; however, the cytotoxic effect was observed only for 7% Selol. Our results show that 2% Selol acts as a monofunctional inducer of phase 2 enzyme activity, and the induction is mediated by the Nrf2 transcription factor. Selol 7% acts in an opposite manner and induces phase 1 with simultaneous inhibition of phase 2 enzyme activity. The differential effect can be associated with the increase in Se content, leading to a change in the structure of the compound.

Evaluation of mutagenic activity of the organo-selenium compound Selol by use of the Salmonella typhimurium mutagenicity assay

We examined the mutagenic activity of the anti-oxidant Selol, an organo-selenium compound, by use of the Salmonella typhimurium mutagenicity assay (Ames test) with strains TA97a, TA98, TA100, TA 1535 and TA102 in the absence and in the presence of metabolic activation with an S9 fraction from Aroclor-induced rat liver. Doses were 330, 500, 1000 and 5000 microg per plate. Selol contains the element selenium (valency, +4) in its structure and it may have chemopreventive and anticancer activity. Selol was found to be non-toxic and non-mutagenic for test doses up to 5% per plate (which designates the declared content of Selenium (+4) as 5000 microg per plate) in all the S. typhimurium strains.

The activity of Selol in multidrug-resistant and sensitive human leukemia cells

Selol is a mixture of selenitetriglycerides synthesized from sunflower oil. As it contains the element selenium in its structure, it is suspected to exhibit chemopreventive and anticancer activity. In this study, the ability of Selol to inhibit cell proliferation and to induce apoptosis was investigated. Three cell lines were used: leukemia HL-60 cell line and multidrug-resistant HL-60/Dox (resistant to doxorubicin) and HL-60/Vinc (resistant to vincristine). Selol was shown to reduce the cell number as a result of treatment with increasing concentrations. For selected concentrations the evidence of apoptosis (changes in mitochondrial potential and caspase activity) was investigated, as well as changes in lysosome distribution. The study has shown that Selol overcame the cell resistance, as doxorubicin-resistant cells were more sensitive towards Selol than sensitive cells.

Changes in antioxidant defense systems induced by thiram in V79 Chinese hamster fibroblasts

The role of antioxidant defence systems in protection against oxidative damage of lipids and proteins induced by fungicide thiram during in vitro exposure was investigated in cultured Chinese hamster V79 cells with normal, depleted, and elevated glutathione (GSH) levels. We analyzed the catalytic activities of superoxide dismutases (SOD1 and SOD2), Se-dependent and Se-independent glutathione peroxidases (GSH-Px), glutathione reductase (GR), and catalase (CAT), as well as total glutathione/glutathione disulfide ratio (GSH(total)/GSSG). Thiram treatment resulted in an increase in activities of SOD1, Se-dependent GSH-Px, and GR at the highest tested dose (150 microM). On the contrary, inhibition of CAT and Se-independent GSH-Px activities, and no significant changes in the level of SOD2 activity was observed at any tested doses (100-150 microM). GSH(total)/GSSG ratio in the 100 microM thiram treated cells was not significantly changed comparing to the control, despite significant decrease of GSH total (50%). In 150 microM thiram treated cells the ratio falls to 43% of control value. Pretreatment with l-buthionine sulfoximine (L-BSO), an inhibitor of GSH synthesis, significantly enhanced decrease in CAT and Se-independent GSH-Px activities, as well as GSH(total)/GSSG ratio, and reduced Se-dependent GSH-Px activity, following exposure to thiram. Simultaneously, L-BSO pretreatment enhanced increase in SOD1 activity, and had no effect on SOD2, following thiram exposure. Pretreatment with N-acetyl cysteine (NAC), a GSH precursor, prevented enzymatic changes in CAT, Se-dependent GSH-Px, GR, SOD1 activities, and significantly decreased SOD2 activity following exposure to thiram. GSH(total)/GSSG ratio was restored to the control value. This study suggests that following the changes in antioxidant defense systems thiram can act through the production of free radicals.

RP-HPLC determination of paraoxonase 3 activity in human blood serum

The aim of the present work was to establish conditions for paraoxonase 3 (PON3) activity determination in human blood serum with simvastatin (SV) as a substrate. The activity of PON3 is considered as a good early predictor of susceptibility to premature atherosclerosis as well as of statin therapy effectiveness. The method used quantifies the SV and beta,delta-dihydroxyacid simvastatin (SVA) liberated from SV after incubation with blood serum, followed by deproteinization of the reaction mixture. Separation of SV and SVA was performed on an LC(18) column by isocratic elution with acetonitrile-K-phosphate buffer of pH 4.5 (v/v, 70:30) as a mobile phase at flow rate of 1.5 ml min(-1). Detection based on ultraviolet absorption at a wavelength of 239 nm was reliable for the simultaneous assay of SV and SVA. The applied method was sufficiently sensitive, precise and accurate for determination of low simvastatin lactone hydrolase (statinase) activity in blood serum of children (1.97-6.86 pmol min(-1) ml(-1)). The method is characterized by good linearity over the measurement range of 0.5-6 microg ml(-1) (1.194-14.3 nmol ml(-1)). Limits of detection (LOD) and quantitation (LOQ) for SV were 3.1 and 10.4 ng ml(-1), respectively. In case of SVA, LOD and LOQ were 4.7 and 14.44 ng ml(-) for a 20 microl sample, respectively. Precision and accuracy of PON3 statinase activity determination in human blood serum with SV as substrate were satisfactory and acceptable for bioanalytical methods.

Specific spectrophotometric method with trifluoroacetic acid for the determination of selenium(IV) in selenitetriglycerides

The role of selenium as an antioxidant and anticancer agent is very well documented in the literature. Selenium compound showing the highest activity as a free radicals scavenger and as an anticancer agent should contain selenium at +4 oxidation level. The synthesis of selenitetriglycerides (named selol) was carried out in the Department of Drug Analysis at Warsaw Medical University (Polish Patent 1999). Selenitetriglycerides showed a dimeric structure. In a single dose toxicity studies performed in rats, LD50 was 100 mg Se kg(-1) after oral administration of selol. The subcutaneous and intraperitoneal administration of selol showed extremely low toxicity. The aim of this work was to develop a new specific method for the determination of Se(IV) in selol. We stated that selenitetriglycerides react quantitatively with trifluoroacetic acid (TFA) in dichloromethane giving a red-coloured conjugate. However, recorded spectrum showed the maximum absorption in the wavelength 380 nm. The optimal conditions of the reaction were established, namely temperature 35 degrees C and reaction time 35 min. The reaction was proved to be specific because neither selenites nor other selol constituents react with TFA. The constructed calibration curve obeyed the Lambert-Beer law in the range of 0.1-7.4 mg ml(-1). Molar absorption coefficient is epsilon =9.46 x 10(3) l mol(-1) cm(-1) and epsilon =2.36 x 10(5) l mol(-1) cm(-1) calculated for selenium and selenitetriglyceride dimer (m.w. 1972.72), respectively. Obtained results for selenium determination were confirmed by AAS method. The developed method showed specificity and high sensitivity.

New HPLC method for separation of blood plasma phospholipids

The aim of the present work was to develop a new HPLC method for separation of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and lysophosphatidylcholine (LPC) from small-volume samples of blood plasma. Human plasma glycerophospholipids were separated by liquid-liquid extraction method followed by solid phase extraction (SPE) on aminopropyl columns. Reversed-phase Sephasil C8 column (10 cm x 2.1 mm, I.D. 5 microm) and micropreparative chromatograph "SMART" were used for separation of PC, PE, LPC and PI from SPE phospholipids extract. Binary-step gradient of eluent A: acetonitrile-methanol (130:5, v/v) and B (0.01% trifluoroacetic acid) provided good, fast and reproducible resolution of investigated phospholipids classes in 12 min at 30 degrees C. Eluted phospholipids were detected at wavelengths lambda=235 and 254 nm. This method made it possible to determine quantitatively: 5 microg ml(-1) PC, 1 microg ml(-1) LPC, 4 microg ml(-1) PE and 3 microg ml(-1) PI in blood plasma samples.

Ascorbyl palmitate as a carrier of ascorbate into neural tissues

We have investigated the hypothesis that a lipid-soluble derivative of ascorbic acid, ascorbyl-6-palmitate (AP), could serve as a carrier of ascorbate into neural tissues. Ascorbate could then exert its physiological effects in the biomembranes that are the target sites of the cellular signaling pathways which are normally hardly accessible to this water-soluble compound. The potential role of AP would require that it penetrates into tissues. The major objective of the study was to determine whether ascorbate could be recovered from cerebral cortex and carotid body tissues, both sensitive to the hypoxic stimulus, after AP given by gavage. Biological samples were analyzed by HPLC for the determination of ascorbate. We found that ascorbate was recovered from the tissues studied. Its content was higher in both tissues, by nearly an order of magnitude, after ingestion of AP than after ingestion of ascorbic acid, and the ascorbate level was higher in the carotid body than in the cortex. Hypoxia decreased the ascorbate content which implies physiological activity of ascorbate carried alongside the AP molecule. The lipophilic AP was able to cross biological barriers and satisfied the tissue demand for ascorbate better than the hydrophilic form. AP should be considered as the preferred form of transport of ascorbate into neural tissues. The results of this study suggest wider pharmacological applications of ascorbyl palmitate.

Pharmacokinetics of selol, a new agent containing selenium, in rats

The pharmacokinetic properties of selol, a new organoselenium compound, were evaluated in rats. Each animal was given a single oral or subcutaneous dose of selol 12 mg/kg. The selenium concentration was determined in whole blood and tissues by non flame carbon furnace atomic-absorption spectrometry. The pharmacokinetic parameters Cmax and tmax differed statistically between oral (p.o.) and subcutaneous (s.c.) treatment. The selenium average peak concentrations in the blood were 494 +/- 8 ng/ml after oral and 322 +/- 5 ng/ml after subcutaneous administration. They were reached after 1.9 +/- 0.1 h and 2.4 +/- 0.1 h, respectively. For the AUC0 mean values of 1373 +/- 56 ng.h/ml (p.o.) and 1273 +/- 137 ng.h/ml (s.c.) were found. The mean residence time (MRT) was significantly longer after subcutaneous administration. Selenium distributes quickly to the main organs with prevalence to the adrenal gland. Moreover, its concentrations in the examined organ were evidently higher after subcutaneous treatment as compared to the oral route. Our data suggest that Selol may be used as a possible source of selenium for the treatment of selenium-deficient patients, particularly via the subcutaneous route.

The enkephalin-hydrolytic activity of cerebral and cardiac muscle tissue in Wistar rats with streptozotocin diabetes

Enkephalin-hydrolytic activity was evaluated in cerebral and cardiac tissue of Wistar rats with experimental streptozotocin-induced diabetes by comparison of the degree of amino acid cleavage from leu-enkephalin in vitro. Ninety days after induction of diabetes the enkephalin-hydrolytic activity was elevated in the cerebral tissue but depressed in the cardiac muscle.