Nano-sized formazan analogues: Synthesis, structure elucidation, antimicrobial activity and docking study for COVID-19

Three series of nanosized-formazan analogues were synthesized from the reaction of dithiazone with various types of α-haloketones (ester and acetyl substituted hydrazonoyl chlorides and phenacyl bromides) in sodium ethoxide solution. The structure and the crystal size of the new synthesized derivatives were assured based on the spectral analyses, XRD and SEM data. The antibacterial and antifungal activities were evaluated by agar diffusion technique. The results showed mild to moderate antibacterial activities and moderate to potent antifungal activities. Significant antifungal activities were observed for four derivatives 3a, 3d, 5a and 5g on the pathogenic fungal strains; Aspergillus flavus and Candida albicans with inhibition zone ranging from 16 to 20 mm. Molecular docking simulations of the synthesized compounds into leucyl-tRNA synthetase editing domain of Candida albicans suggested that most formazan analogues can fit deeply forming stable complexes in the active site. Furthermore, we utilized the docking approach to examine the potential of these compounds to inhibit SARS-CoV-2 3CLpro. The results were very promising verifying these formazan analogues as a hopeful antiviral agents.

Cytotoxicity of bismuth nanoparticles in the murine macrophage cell line RAW 264.7

A promising use of bismuth nanoparticles (BiNPs) for different biomedical applications leads to a search for the elucidation of their toxicity mechanisms, since toxicity studies are still at early stage. In the current study, cytotoxic effects of BiNPs produced by laser ablation in solution (LASiS) was investigated in the murine macrophage line RAW 264.7. The cells were exposed to 0.01-50 µg ml^-1 of BiNPs for 24 and 48 h and then cytotoxicity assays were performed. Decrease of MTT conversion to formazan and of cell attachment were observed with no effects on cell proliferation. No loss of membrane integrity or significant changes of ROS and RNS levels were observed in exposed cells. Foremost, increased phagocytic activity and DNA repair foci occurred for cells exposed to BiNPs. These effects are important findings that must be considered in the case of biomedical application of BiNPs, since inappropriate macrophages activation and inactivation may lead to immunotoxicity. Bismuth nanoparticles (BiNPs) produced by laser ablation in solution and stabilized with BSA decrease enzyme-dependent MTT conversion to formazan and increase phagocytic activity and DNA repair foci in murine macrophage line RAW 264.7 when exposed to 50 µg ml^-1. These effects are findings that should be considered in the case of biomedical application of BiNPs, since inappropriate macrophages activation and inactivation may lead to immunotoxicity.

Colorimetric method for determining viability of sea urchin sperm applied in toxicity tests

The aim of this study was to improve the methodological procedure for the evaluation of sea urchin (Lytechinus variegatus) sperm sensitivity in MTT (3-(4,5-dimethylthiazol-2yl)-2,5 diphenyltetrazolium bromide) enzyme reduction assays with the formation of formazan (purple color) in the interior of viable cells. Assays were carried out with the reference toxicants sodium dodecyl sulfate (SDS), copper, zinc, cadmium and ammonium, using a sperm solution previously activated in sea water and a sperm solution prepared in sea water containing 400 μg L^-1 verapamil, which enabled activation of the sperm to occur only when exposed to the toxicants. The assays performed with sperm in verapamil presented similar sensitivity to that shown in the fertilization tests with copper, zinc and SDS, while the assays carried out with the pre-activated sperm solution presented greater resistance to the action of the toxicants. It appears that the action of verapamil involves an intracellular effect on the distribution of Ca²⁺ ions and that the toxicants used prevent the metabolic reactivation of the sperm.

Selective Conversion of CO2 into Isocyanate by Low-Coordinate Iron Complexes

Discovery of the mechanisms for selective transformations of CO2 into organic compounds is a challenge. Herein, we describe the reaction of low-coordinate Fe silylamide complexes with CO2 to give trimethylsilyl isocyanate and the corresponding Fe siloxide complex. Kinetic studies show that this is a two-stage reaction, and the presence of a single equivalent of THF influences the rates of both steps. Isolation of a thermally unstable intermediate provides mechanistic insight that explains both the effect of THF in this reaction, and the way in which the reaction achieves high selectivity for isocyanate formation.

Ultralow thermal conductivity of atomic/molecular layer-deposited hybrid organic-inorganic zincone thin films

Atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques with atomic level control enable a new class of hybrid organic-inorganic materials with improved functionality. In this work, the cross-plane thermal conductivity and volumetric heat capacity of three types of hybrid organic-inorganic zincone thin films enabled by MLD processes and alternate ALD-MLD processes were measured using the frequency-dependent time-domain thermoreflectance method. We revealed the critical role of backbone flexibility in the structural morphology and thermal conductivity of MLD zincone thin films by comparing the thermal conductivity of MLD zincone films with an aliphatic backbone to that with aromatic backbone. Much lower thermal conductivity values were obtained in ALD/MLD-enabled hybrid organic-inorganic zincone thin films compared to that of the ALD-enabled W/Al2O3 nanolaminates reported by Costescu et al. [Science 2004, 303, 989-990], which suggests that the dramatic material difference between organic and inorganic materials may provide a route for producing materials with ultralow thermal conductivity.

Sensitive metal ions (II) determination with resonance Raman method

In this paper, a new proposal for the quantitative evaluation of divalent metal ions (M(2+)) is developed by the use of the competitive resonance Raman (RR)-based method. Upon excitation with light of the appropriate wavelength (532 nm), a strong electric field is generated that couples with the resonance of the complex (zincon-M(2+)), increasing the character signals of these complexes, resulting in sensitive detection. Herein, the RR probe, zincon-M(2+) complex that the RR intensity gets lower with the decreasing of the M(2+) concentration, which leads to the transformation of the Raman information. As a result, by using the proposed RR-based method, we could find the liner calibration curves of Cu(2+) and Ni(2+), which show the potential in quantitative evaluation of an unknown sample. In addition, the abundant fingerprint information shows that RR leads to the successful analysis of a blended solution, which contains two ions: Cu(2+) and Ni(2+).

Cytotoxicity of gold nanoparticles

Nanomaterials are now routinely used in technical as well as medical applications. The very physicochemical properties that favor nanomaterial application are the prime cause that these materials cannot be considered "generally safe." We are still far from predicting the toxicological profile of new nanoparticles, despite continuous attempts to establish a structure-function relation between the physical and chemical properties of nanoparticles and their interactions with biological systems. Herein, we summarize some basic concept to assess nanoparticle toxicity, death pathways, cell cycle, and oxidative stress in response to nanoparticle exposure of cells.

Bioassay-guided isolation of an alkaloid with antiangiogenic and antitumor activities from the extract of Fissistigma cavaleriei root

Fissistigma cavaleriei (Levl) Rehd (Annonaceae) is used as a folklore medicine for treatment of inflammation, arthritis, and tuberculosis by Miao people in China. In the present study, the antiangiogenic activity of F. cavaleriei was investigated. The chorioallantoic membrane of the fertilized hen's egg (CAM assay) was used to determine antiangiogenic activity of the plant extract. Compound (1), a compound with antiangiogenic activity, was isolated by bioassay-guided fractionation from F. cavaleriei for the first time. The structure of compound (1) was elucidated on the basis of spectroscopic methods. Colorimetric COX (ovine) inhibitor screening assay was used to determine its inhibitory effect on COX-1 and COX-2. MTT and Sulforhodamine B assays were used to investigate its cytotoxic effects on tumor cell lines. As a result, compound (1) showed a selectively inhibiting effect on COX-2 and could inhibit the growth of tumor cells in vitro. The antitumor activity of compound (1) was further confirmed by the observation that compound (1) administration significantly inhibited the growth of S-180 cells in mice. Moreover, compound (1) was able to enhance the antitumor activity of doxorubicin in the mice bearing with S-180 cells while combined with doxorubicin. In conclusion, compound (1) is a multi-target molecule and further experimental investigations are needed to determine whether it can be used as a lead molecule for tumor treatment.

Alternol exerts prostate-selective antitumor effects through modulations of the AMPK signaling pathway

BACKGROUND

Alternol is an original compound purified from the fermentation products of Alternaria alternata var. monosporus, a microorganism from the bark of the yew tree. It has been reported that Alternol can inhibit proliferation of mouse leukemia cells and human gastric carcinoma cells, the aim of this study was to investigate the effects of Alternol on prostate cancer cells in comparison to prostate cells.

METHODS

The MTT assay was utilized to assess cell viability. Cell cycle was analyzed by flow cytometry with propidium iodide staining. Protein expression levels were examined by Western blotting.

RESULTS

Alternol treatment resulted in a significant decrease in the viability of prostate cancer cells but had lesser effects on prostate cells. Alternol inhibited AMP-activated protein kinase (AMPK) phosphorylation in prostate cancer C4-2 cells but stimulated AMPK phosphorylation in prostate RWPE-1 cells. Inhibition of p27 phosphorylation was observed in C4-2 cells whereas a promotion of p27 phosphorylation was seen in RWPE-1 cells. Alternol treatment resulted in a profound increase in the LC3II/LC3I protein ratio in RWPE-1 cells but not in C4-2 cells. A dose-dependent down-regulation of Bcl-2 protein was detected in C4-2 cells but not in RWPE-1 cells. Pretreatment of cells with Compound C (AMPK inhibitor) before Alternol treatment abolished the selective antitumor effect of Alternol.

CONCLUSIONS

These results reveal for the first time that Alternol exerts a selective antitumor effect on prostate cancer cells when compared with RWPE-1 prostate epithelial cells. In addition, the AMPK signaling pathway is responsible for the selective antitumor effects of Alternol.

Counterion dye staining of proteins in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tryptic gel digestion of stained protein for mass spectrometry

A fast and matrix-assisted laser desorption/ionization mass spectrometry compatible protein staining method in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis is described. It is based on the counterion dye staining method that employs oppositely charged two dyes, zincon and ethyl violet, to form an ion-pair complex. The protocol, including fixing, staining, and quick washing steps, can be completed in 1-1.5 h, depending upon gel thickness. It has the sensitivity comparable to the colloidal Coomassie Brilliant Blue G stain using phosphoric acid as a component of staining solution (4-8 ng). The counterion dye stain does not induce protein modifications that complicate interpretation of peptide mapping data from mass spectrometry. Considering the speed, sensitivity, and compatibility with mass spectrometry, the counterion dye stain may be more practical than any other dye-based protein stains for routine proteomic researches.

Cell sensitivity assays: the MTT assay

The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay is based on the conversion of MTT into formazan crystals by living cells, which determines mitochondrial activity. Since for most cell populations the total mitochondrial activity is related to the number of viable cells, this assay is broadly used to measure the in vitro cytotoxic effects of drugs on cell lines or primary patient cells. In this chapter the protocol of the assay is described including important considerations relevant for each step of the assay as well as its limitations and possible applications.

Quantitative determination of superoxide in plant leaves using a modified NBT staining method

INTRODUCTION

In plants, the ROS (reactive oxygen species) level is tightly regulated because their accumulation produces irreversible damage leading to cell death. However, ROS accumulation plays a key role in plant signaling under biotic or abiotic stress. Although various methods were reported to evaluate ROS accumulation, they are restricted to model plants or provide only qualitative information.

OBJECTIVE

Develop a simple method to quantify superoxide radicals produced in plant tissues, based on the selective extraction of the formazan produced after nitroblue tetrazolium (NBT) reduction in histochemical staining.

METHODOLOGY

Plant leaves were stained with a standard NBT method and the formazan precipitated in tissues was selectively extracted using chloroform. The organic phase was dried and formazan residue dissolved in dimethylsulfoxide-potassium hydroxide and quantified by spectrophotometry. The method was tested in strawberry plant leaves under different stressing conditions.

RESULTS

Formazan extracted from leaves subjected to stress conditions showed similar absorption spectra to those obtained from standard solutions using pure formazan. Calibration curves showed a linear relationship between absorbance and formazan amounts, within the range 0.5-8 µg. Outcomes suggested that formazan was retained in the solid residue of leaf tissues. This protocol allowed us to quantify superoxide radicals produced under different stress conditions.

CONCLUSIONS

Chloroform allowed a selective formazan extraction and removal of potential endogenous, exogenous or procedural artefacts that may interfere with the quantitative determination. This protocol can be used to quantify the superoxide produced in plant tissues using any traditional qualitative NBT histochemical staining method.

Parthenolide, an NF-κB inhibitor, suppresses tumor growth and enhances response to chemotherapy in gastric cancer

AIM

This study evaluated the sesquiterpene lactone parthenolide, an inhibitor of transcription factor nuclear factor-kappaB (NF-κB), in the treatment of gastric cancer in vitro and in vivo.

MATERIALS AND METHODS

In vitro, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to evaluate the effect of parthenolide on growth inhibition and chemosensitization to antitumor drugs of three gastric cancer cell lines (MKN-28, MKN-45 and MKN-74). Microarray analysis was performed to identify genes which were up- or down-regulated on the treatment of parthenolide. The isobologram analysis was introduced to evaluate the synergic effect of parthenolide on antitumor drugs. In vivo, the effect of parthenolide was investigated in a mouse peritoneal dissemination model with and without chemotherapy.

RESULTS

Parthenolide significantly inhibited cell growth in three gastric cancer cell lines. The phosphorylation of NF-κB was down-regulated by the treatment of parthenolide. The synergic effect of parthenolide was confirmed in combination with paclitaxel and cisplatin. In the peritoneal dissemination model, parthenolide significantly suppressed the disseminated nodules as a single agent and also enhanced chemosensitivity to paclitaxel. Furthermore, the combined therapy of parthenolide and paclitaxel significantly contributed to prolonging the survival duration.

CONCLUSION

The NF-κB inhibitor, parthenolide, may enhance chemosensitivity to paclitaxel in the treatment of patients with gastric cancer.

A Drug-Based Cellular Assay (DBCA) for studying cytotoxic and cytoprotective activities of the prion protein: A practical guide

Although a great deal of progress has been made in elucidating the molecular identity of the infectious agent in prion diseases, the mechanisms by which prions kill neurons, and the role of the cellular prion protein (PrP(C)) in this process, remain enigmatic. A window into the normal function of PrP(C), and how it can be corrupted to produce neurotoxic effects, is provided by a PrP deletion mutant called ΔCR, which produces a lethal phenotype when expressed in transgenic mice. In a previous study, we described the unusual observation that cells expressing ΔCR PrP are hyper-sensitive to the toxic effects of two cationic antibiotics (G418 and Zeocin) that are typically used for selection of transfected cell lines. We have used this drug-sensitizing effect to develop a simple Drug-Based Cell Assay (DBCA) that reproduces several features of mutant PrP toxicity observed in vivo, including the rescuing activity of wild-type PrP. In this paper, we present a detailed guide for executing the DBCA in several, different experimental settings, including a new slot blot-based format. This assay provides a unique tool for studying PrP cytotoxic and cytoprotective activities in cell culture.

Expression of trophic amidated peptides and their receptors in benign and malignant pheochromocytomas: high expression of adrenomedullin RDC1 receptor and implication in tumoral cell survival

Pheochromocytomas are catecholamine-producing tumors which are generally benign, but which can also present as or develop into malignancy. Molecular pathways of malignant transformation remain poorly understood. Pheochromocytomas express various trophic peptides which may influence tumoral cell behavior. Here, we investigated the expression of trophic amidated peptides, including pituitary adenylate cyclase-activating polypeptide (PACAP), neuropeptide Y (NPY), and adrenomedullin (AM), and their receptors in benign and malignant pheochromocytomas in order to assess their potential role in chromaffin cell tumorigenesis and malignant transformation. PACAP, NPY, and AM are expressed in the majority of pheochromocytomas studied; NPY exhibiting the highest mRNA levels relative to reference genes. Although median gene expression or peptide levels were systematically lower in malignant compared to benign tumors, no statistically significant difference was found. Among all the receptors of these peptides that were analyzed, only the AM receptor RDC1 displayed a differential expression between benign and malignant pheochromocytomas. This receptor exhibited a fourfold higher expression in malignant than in benign tumors. AM and stromal cell-derived factor 1, which has also been described as a ligand for RDC1, increased the number of human pheochromocytoma cells in primary culture and exerted anti-apoptotic activity on rat pheochromocytoma PC12 cells. In addition, RDC1 gene silencing decreased the number of viable PC12 cells. This study shows the expression of several trophic peptides and their receptors in benign and malignant pheochromocytomas, and suggests that AM and its RDC1 receptor could be involved in chromaffin cell tumorigenesis through pro-survival effects. Therefore, AM and RDC1 may represent valuable targets for the treatment of malignant pheochromocytomas.

Evaluation of the effect of Thai breadfruit's heartwood extract on the biological functions of fibroblasts from wrinkles

In previous studies, extract from Artocarpus incisus's heartwood (breadfruit tree) had antioxidant and antimelanogenic activities. Here, we investigated the extract's action on facial skin fibroblasts from wrinkled skin and nonwrinkled skin biopsies, particularly in the production of type I procollagen and metalloproteinase- 1 (MMP-1) and in the reorganization of collagen fibers. We found that the extract at a concentration of 50 microg/ml significantly enhanced percent viability and proliferation of wrinkled-skin fibroblasts. Flow cytometry showed that a 3.6-fold increased proportion of the wrinkled-skin fibroblasts were in their cell cycle S-phase, indicating increased proliferation. Type I procollagen synthesis by wrinkled-skin fibroblasts was augmented by the extract. Nonwrinkled-skin fibroblasts had higher synthesis and were unaffected by the extract. MMP-1 secretion was greater for wrinkled-skin fibroblasts, but the extract decreased its secretion for both fi broblasts samples. Fibroblasts were incorporated in collagen lattice disks. Lattices with nonwrinkled-skin fibroblasts contracted uniformly by 56% after a three-day culture and the extract had little effect. However, wrinkled-skin fi broblast lattices failed to show appreciable contractions (to 12% after three days). But remarkably, the extract conferred an ability of the wrinkled-skin fibroblast lattices to fully contract (to 53%). This shows that wrinkled-skin fi broblasts have the ability to reorganize collagen but that the extract can reactivate this latent potential. Our findings for the first time reveal that A. incisus's heartwood extract reversed the fibroblast deficiencies in the metabolism and reorganization of collagen and may underlie a wrinkle treatment.

Levonorgestrel inhibits proliferation and induces apoptosis in uterine leiomyoma cells

BACKGROUND

The levonorgestrel intrauterine system (LNG-IUS) is a widely recognized intrauterine anti-fertility system, which can alleviate symptoms of uterine leiomyoma. This study aims to evaluate leimyoma cell growth inhibition induced by high concentrations of LNG.

STUDY DESIGN

After treatment with LNG, the growth rate of the cultured primary uterine leiomyoma cells was studied with methyl thiazolyl tetrazolium (MTT) assay. Cell apoptosis rate was determined by morphological changes and flow cytometry. Reverse transcription polymerase chain reaction (RT-PCR) and Western blotting were performed to measure the differential mRNA and protein expression levels.

RESULTS

The proliferation rate of uterine leiomyoma cells was suppressed after treatment with LNG at a minimum concentration of 10 mcg/mL. The inhibitive effect was positively correlated with the LNG concentration and with the incubation time. Flow cytometry showed that the apoptosis rate was increased with the LNG concentration. The mRNA levels of IGF-1, Bcl-2 and survivin were down-regulated significantly after treatment with 10 mcg/mL LNG. Western blot analysis confirmed that the expression of Bcl-2 and survivin was decreased significantly, and the p38 phosphorylation level was increased and caspase 3 was activated remarkably 72 h after treatment with 10 and 20 mcg/mL LNG.

CONCLUSIONS

This study demonstrated that LNG may suppress the proliferation and induce apoptosis of the uterine leiomyoma cells.

Sesquiterpene lactones from Inula oculus-christi

Inula oculus-christi L. (Compositae) extract was chromatographed and three sesquiterpene lactones ergolide, gaillardin and pulchellin C were isolated. The structures of these compounds were determined by analysis of their spectroscopic data, and their crystal structures were defined using X-ray crystallography; the isolation of ergolide and pulchellin C is reported for the first time from this species. These three compounds were evaluated for their in vitro cytotoxic activity against MDBK, MCF7 and WEHI164 cells; ergolide and gaillardin exhibited lower and significantly different IC50 values compared with pulchellin C (p<0.001).

Evaluation of inhibitory effects of thiobarbituric acid derivatives targeting HCV NS5B polymerase

A series of thiobarbituric acid derivatives were constructed and evaluated for inhibitory activity on hepatitis C virus NS5B polymerase. In biochemical assays using purified viral polymerase and RNA template, the IC(50) value was improved to 0.41 microM from the original compound's 1.7 microM value. In HCV subgenomic replicon assay, the EC(50) value was improved to 3.7 microM from the original compound's 12.3 microM value. CC(50) was higher than 77 microM for all compounds tested, suggesting that they are useful candidates for anti-HCV therapy.

Synthesis, spectroscopy, and quantum-chemical calculations on 1-substituted phenyl-3,5-diphenylformazans

In this study 1-substituted phenyl-3,5-diphenylformazans were synthesized from benzaldehyde-N-phenylhydrazone and appropriate phenyldiazonium salts having CH(3), Br, and Cl at the o-, m-, and p-positions of 1-phenyl ring. Their structures were determined by infrared and ultraviolet-visible spectra. Bathochromic effect in accordance with the electron-donating effect of CH(3), Br, and Cl group and its magnitude were dependent upon type and position of substituent on the ring. The ground-state geometries and absorption wavelengths for 1-phenyl substituted formazans were studied with density functional theory and time-dependent density functional theory. The calculations were carried out by using PBE1PBE functional with 6-311G(2d,2p) basis set for lambda(max) of the UV-vis spectra for the studied formazans. A good agreement was obtained between the experimental and computed values.

Rational design of novel antiandrogens for neutralizing androgen receptor function in hormone refractory prostate cancer

BACKGROUND

The standard hormonal therapy with currently available antiandrogens and the leutinizing hormone releasing hormone (LHRH) analogs is not effective in the hormone-refractory stage of prostate cancer due to changes in androgen receptor (AR) signaling axis. In this refractory stage, AR continues to play a significant role in the growth of cancer cells even though the cancer cells are no longer dependent on the level of circulating androgens.

METHODS

A series of 11beta-Delta(9)-19 nortestosterone compounds were designed through structure-based rationale and tested for their binding affinity against AR and glucocorticoid receptor (GR) using fluorescence polarization assays, their agonistic ability to induce AR dependent transcription using PSA-driven report gene assays, and their growth inhibitory affects against a series of AR positive (LAPC4, LNCap, and CWR22R) and negative human prostate cancer cell lines (PC3) using MTT cell proliferation assays.

RESULTS

This study proposes the design of novel bifunctional antiandrogens based on the conjugation of 11beta and/or 7alpha-Delta(9)-19 nortestosterone class of steroidal compounds to the synthetic ligand for FK506-binding proteins. As a critical step towards the development of bifunctional antiandrogens, highly potent and AR-specific lead compounds were identified using in vitro data. The lead compounds identified in this study possessed low binding affinity for GR, indicating the absence of undesirable antiglucocorticoid activity.

CONCLUSIONS

The results of this study validate our drug discovery rationale based on the structural biology of AR and pave the pay for future development of bifunctional compounds in order to block AR function in hormone refractory stage of prostate cancer.

Immunomodulating activities of water-soluble exopolysaccharides obtained from submerged culture of Lentinus lepideus

Immunomodulating activities of water-soluble exopolysaccharides (LL-EX) obtained from submerged mycelial culture of Lentinus lepideus were studied and their effectiveness was compared with lipopolysaccharide (LPS). The influence of the LL-EX on macrophage cellular lysosomal enzyme activity was to stimulate up to 267%, 392%, and 464% at the level of 10, 50, and 100 microg/ml, respectively. When the LL-EX was further fractionated into LL-Fr.I and Fr.II by Sepharose CL-6B gel chromatography, the cellular lysosomal enzyme activity of LL-Fr.II (2.1- fold) was higher than Fr.I (1.2-fold). Moreover, both LL-Fr.I and Fr.II stimulated the cytokines IL-1beta, TNF-alpha, and IL-6 in macrophages. In mixed lymphocyte reaction, LL-Fr.I and Fr.II enhanced the splenocyte proliferation up to 1.2-fold and 1.4-fold (50 microg/ml), respectively, stimulating only T lymphocytes. The fractions of LL-EX not show any direct toxicity against human gastric adenocarcinoma cell (AGS). The molecular masses of LL-Fr.I and Fr.II were estimated to be about 1,986 kDa and 21 kDa, respectively. The total sugar and protein contents of the two fractions were 84.97% and 69.88% and 15.03% and 30.12%, respectively. The sugar and amino acid compositions of the LL-Fr.I and Fr.II were also analyzed in detail.

Upregulation of ATP-sensitive potassium channels for estrogen-mediated cell proliferation in human uterine leiomyoma cells

OBJECTIVES

The objectives of the present study were to evaluate the expression level of ATP-sensitive potassium (K(ATP)) channels in smooth muscle cells in human uterine leiomyoma and the involvement of the channel in potentiating effect of estrogen on leiomyoma growth.

METHODS

Reverse transcription-polymerase chain reaction (RT-PCR), real-time PCR and Western blot were used for the identification and quantification of K(ATP)-channel subunits in the control myometrial and leiomyoma cells. Furthermore, we measured the K(ATP)-channel activity in enzymatically isolated single uterine smooth muscle cells by whole-cell patch-clamp recordings. The estrogen-induced cell proliferation in leiomyoma was measured by the MTT assay.

RESULTS

The subunits of K(ATP) channels (Kir6.1, Kir6.2, SUR2B) were more highly expressed in leiomyoma cells than in control cells. The whole-cell currents mainly through K(ATP) channels were also greater in the leiomyoma cells. Estrogen applied in the bath solution could acutely enhance the channel activity. Estrogen-induced proliferation of the leiomyoma cells was inhibited by pretreatment with glibenclamide, a K(ATP)-channel inhibitor.

CONCLUSION

Estrogen may induce the proliferation of leiomyoma cells, at least in part, by activating the K(ATP) channel. Increased expression of the K(ATP) channel may be a causal factor for the high growth rate of uterine leiomyoma.

Synthesis and spectral properties of some bis-substituted formazans

Novel, 1,4-bis-[3,3'-phenyl-5,5'-(o-carboxyphenyl)-formaz-1-yl]-benzene-o-sulphonic acid and its derivatives contained OH group at the o-, m-, p-positions of the 3-phenyl ring were synthesized. The structures of the formazans were confirmed by elemental analyses, GC-mass, IR, (1)H NMR, UV-vis spectra. Their absorption properties were investigated. It was seen that lambda(max) values shifted towards shorter wave lengths by 130nm in CSPF relative to 1,3,5-triphenylformazan (TPF) due to the fact that the structure of CSPF contained electron withdrawing COOH and SO(3)H groups (hypsochromic effect). With binding of OH group to 3-phenyl ring of CSPF, it was observed a small bathochromic effect in accordance to the electron donating effect of OH group.

Contribution of MX dynamin, oligoadenylate synthetase, and protein kinase R to anti-paramyxovirus activity of type 1 interferons in vitro

OBJECTIVE

To determine the contribution of MX dynamin, oligoadenylate synthetase (OAS), and double-stranded RNA-dependent protein kinase R (PKR) to the antiviral effects of type 1 interferons (IFNs) against bovine parainfluenza-3 virus (PI-3V) infection of Vero cells.

SAMPLE POPULATION

Vero cell cultures.

PROCEDURES

PI-3V yield was first compared between control and transfected type 1 IFNs-incompetent Vero cells expressing recombinant OAS or MX proteins. Afterwards, phosphorylation of eukaryotic initiation factor 2 alpha (eIF2alpha) was used to scale the degree of PKR activation upon infection of Vero cells by PI-3V.

RESULTS

Overexpression of OAS did not result in significantly decreased viral replication. Phosphorylated eIF2alpha forms, the hallmark of PKR activation, were not increased in IFNalpha-primed infected Vero cells. Although human MXA contributed to partial blockade of replication of bovine PI-3V, the antiviral effect was not as strong as that of IFNalpha.

CONCLUSIONS AND CLINICAL RELEVANCE

The powerful anti-Paramyxovirus activity of type 1 IFNs is mediated by noncanonic pathways.

LC-MS characterization of efficacy substances in serum of experimental animals treated with Sophora flavescens extracts

Anti-DHBV (duck hepatitis B virus) activity was found in the aqueous extracts of Sophora flavescens Ait. in vivo. Liquid chromatography/electrospray ionization ion trap mass spectrometry was applied to characterize the components in duck serum after oral administration of S. flavescens extract. Oxymatrine (1), sophoranol (2), sophoridine (3) and matrine (4) were identified in the serum. Further research on the four compounds was evaluated for their antiviral activity against HBV (hepatitis B virus) in cell culture. The results suggested that oxymatrine, sophoranol and matrine were the efficacy substances for anti-HBV activity in aqueous extracts of S. flavescens Ait.

ErbB-4 may control behavior of prostate cancer cells and serve as a target for molecular therapy

PURPOSE

To assess ErbB-4 expression in advanced human prostate cancer (PC) cell lines, the role of ErbB-4 in motility, migration, and proliferative/tumorigenic potential of PC cells, and efficacy of anti-ErbB-4 monoclonal antibody (Mab) treatment on PC cells in vitro and tumor growth in vivo.

MATERIALS AND METHODS

Established advanced human PC cell lines (PC-3, Cl-1, and Du-145) were evaluated for ErbB-4 expression. Several Cl-1 cell line clones expressing various levels of ErbB-4 were isolated, their motility, migration capacity, and in vitro proliferation as well as survival following Mab treatment were evaluated. Tumorigenicity and proliferation capacity of these clones in vivo and efficacy of Mab treatment on tumor growth were estimated by measurements of subcutaneous tumors developed in nude mice.

RESULTS

PC cell lines studied express ErbB-4. Both PC-3 and Du-145 cell lines express high ErbB-4 levels; only 50% of Cl-1 cells express ErbB-4 with large heterogeneity. Cl-1 sub-clones highly expressing ErbB-4 showed increased cell motility, migration, and proliferation rate in vitro and enhanced growth in vivo, compared to clones with low ErbB-4 expression. Mab treatment inhibited the growth of cells expressing high but not low ErbB-4 levels in vitro and decreased the growth of subcutaneous tumors in nude mice generated by ErbB-4 highly expressing cells.

CONCLUSIONS

High expression of ErbB-4 in prostate cancer Cl-1 cell clones correlated with high proliferative and migration capacity and high tumorigenic potential. The inhibitory effect of Mab on cell proliferation and on subcutaneous tumor growth suggests ErbB-4's potential as a target for molecular anticancer therapy.

A new anticancer dihydroflavanoid from the root ofSpiranthes australis(R. Brown) Lindl

A new dihydroflavanoid was obtained from the root of Spiranthes australis (R. Brown) Lindl, a traditional Chinese medicinal herb. The structure was elucidated as (2S)-5,2',6'-trihydroxy-6-lavandulyl-4''-(gamma,gamma-dimethylallyl)-2'',2''-dimethylpyrano-[5'',6'' : 7,8]-flavanone by spectroscopic methods including UV, IR, HR-EI-MS, ESI-MS, 1D NMR and 2D NMR techniques, and subsequently, the anticancer activities of the compound to inhibit human cancer cells' growth including A549, BEL-7402, SGC-7901, MCF-7, HT-29, K562, and A498 cell lines by MTT method was evaluated in vitro.

New pyrazolic compounds as cytotoxic agents

The evaluation of the in vitro cytotoxic properties of two pyrazole compounds: 1-(4-nitrophényl)-3,5-diméthylpyrazole (1) and 1,1'-di(4-nitrophényl)-5,5'-diisopropyl-3,3'-bipyrazole (2) was investigated against Hep cell line (Human laryngeal carcinoma). These two compounds showed an important cytotoxic activity on the Hep cell line, with IC(50): 8.25 microg mL(-1) for the compound 1; IC(50): 10.20 microg mL(-1) for the compound 2 while the IC(50) for adriamycine used as positive control was 3.62 microg mL(-1).

Assay of angiotensin I-converting enzyme-inhibiting activity based on the detection of 3-hydroxybutyric acid

Hypertension and related diseases afflict millions of individuals worldwide, and many investigations of angiotensin I-converting enzyme (ACE) activity have been carried out. Most of these have used hippuryl-histidyl-leucine (HHL) as a substrate for ACE reaction with considerable interferences. Here we propose the use of a new substrate, 3-hydroxybutyrylglycyl-glycyl-glycine (3HB-GGG) for the screening of ACE inhibitors. Under the actions of ACE and aminoacylase, 3HB-GGG is cleaved into amino acids (Gly and Gly-Gly) and 3-hydroxybutyric acid (3HB). The assay conditions were optimized and applied to monitor the ACE inhibitory activity in terms of 3HB measured using an F-kit. Under the optimum assay parameters-ACE (0.2 U/ml) and aminoacylase (172 kU/ml) incubated with 3HB-GGG (3.4 mg/ml) at 37 degrees C for 30 min-the Gly-Gly and Gly cleaved from 3HB-GGG by enzymes was able to be identified, affirming the feasibility of substituting 3HB-GGG for the conventional substrate HHL. In addition, the current method was more sensitive, accurate, rapid, and convenient than the conventional method.

HBx or HCV core gene expression in HepG2 human liver cells results in a survival benefit against oxidative stress with possible implications for HCC development

Hepatitis virus replication in the liver is often accompanied by inflammation resulting in the formation of reactive oxygen species (ROS) and nitric oxide (NO) and these may induce cell death. We investigated whether the expression of HBx or HCV core protein in HepG2 cells has an influence on the sensitivity of these cells for oxidative radicals. Our previous study, using the inducible HBV model of HepAD38, revealed that oxidative-stress-related genes are upregulated by virus replication. In the present study, we examined the intracellular pro-oxidant status with dichlorofluorescein (DCF) in HepG2 cell lines transfected with HBx, HbsAg and HCV core. Baseline intracellular oxidative levels were not different in the cell lines expressing viral proteins as compared to control. However, when these cells were exposed to H(2)O(2), the viral protein expressing cells, especially those expressing HBx, showed a reduced level of ROS. This suggests that HBx and HCV core transfected cells can convert H(2)O(2) to less reactive compounds at a higher rate than the control cells. When HBx or HCV core expressing cells were exposed to peroxynitrite (a highly reactive product formed under physiological conditions through interaction of superoxide (O(2)(-)) with NO) these cells were less sensitive to induction of cell death. In addition, these cell lines were less prone to cell death when exposed to H(2)O(2) directly. In conclusion, HBx and HCV core expression in HepG2 cells leads to a survival benefit under oxidative stress which in vivo can be induced during inflammation.

Protective effect of a novel cystine C60 derivative on hydrogen peroxide-induced apoptosis in rat pheochromocytoma PC12 cells

Oxidative stress has been considered as a major cause of cellular injuries in a variety of clinical abnormalities, especially neural diseases. One of the effective ways to prevent the reactive oxygen species (ROS) mediated cellular injury is dietary or pharmaceutical augmentation of free radical scavengers. In the present study, we describe the synthesis and characterization of a novel cystine C(60) derivative (CFD). The compound was analyzed by FT-IR, (1)H NMR, (13)C NMR, LC-MS and elemental analysis. It contains five cystine moieties per C(60) molecule. This water-soluble amino-fullerene derivative was able to scavenge both superoxide and hydroxyl radical with biocompatibility. We investigated its potential protective effects on hydrogen peroxide-induced oxidative stress and apoptotic death in cultured rat pheochromocytoma (PC12) cells. Cells treated with hydrogen peroxide underwent cytotoxicity and apoptotic death determined by MTT assay, flow cytometry analysis, PI/Hoechst 33342 staining and glutathione peroxidase assay. The CFD was able to reduce the accumulation of reactive oxygen species and cellular damage caused by hydrogen peroxide in PC12 cells. RF assay demonstrated that CFD could penetrate through the cell membrane and it has played its distinguished role in protecting PC12 cells against hydrogen peroxide-induced cytotoxicity. The results suggest that CFD has the potential to prevent oxidative stress-induced cell death without evident toxicity. Hence, we can hypothesize that the protective effect of CFD on hydrogen peroxide-induced apoptosis is related to its scavenger activity.

Optimized candidal biofilm microtiter assay

Microtiter based candidal biofilm formation is commonly being used. Here we describe the analysis of factors influencing the development of candidal biofilms such as the coating with serum, growth medium and pH. The data reported here show that optimal candidal biofilm formation is obtained when grown in unbuffered YNB at pH 7, in wells that have been coated with Fetal Calf Serum or Fetal Bovine Serum.

One new anthraquinone from marine Streptomyces sp. FX-58

One new anthraquinone, 1,8-dihydroxy-2-ethyl-3-methylanthraquinone (1), together with two known compounds octadecanoic acid (2) and cholest-4-en-3-one (3) was isolated from marine actinomycete Streptomyces sp. FX-58. The structure of 1 was elucidated on the basis of spectroscopic methods, especially, the 2D-NMR spectral analysis. The cytotoxic activities of 1 were evaluated in vitro.

Evaluation of antimicrobial activity of selected plant extracts by rapid XTT colorimetry and bacterial enumeration

The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the "viable plate count" method. Four degrees of antimicrobial activity (high, moderate, weak and inactive) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, were recorded. The plant extracts of Hypericum triquetrifolium, Ballota undulata, Ruta chalepensis, Ononis natrix, Paronychia argentea and Marrubium vulgare had shown promising antimicrobial activity. This study showed that while both XTT and viable count methods are comparable when estimating the overall antimicrobial activity of experimental substances, there is no strong linear correlation between the two methods.

Inhibitory effects of natural plants of Jeju Island on elastase and MMP-1 expression

In order to search for new active cosmetic ingredients of natural origin, we screened about 60 plants collected from Jeju Island, which is located in the southernmost part of the Republic of Korea. We investigated their free radical scavenging activity, elastase inhibition activity, and reduction of MMP-1 mRNA expression for the development of anti-aging ingredients as raw materials for use in cosmetics. In the free radical scavenging capacity assay, 12 extracts, including Typha orientalis (seed) and Torreya nucifera (leaf), showed significant free radical scavenging activity (up to SC(50)<30 microg/ml). Among these extracts, Nymphaea tetragona (rhizome) extract showed the highest free radical scavenging activity (SC(50)=4.7 microg/ml). In the anti-elastase inhibition assay, seven extracts, including Typha orientalis (seed) and Persicaria hydropiper (whole plant), showed high inhibitory activity (>50% at 100 mug/ml). Among these extracts, Persicaria hydropiper (whole plant) extract showed the highest elastase inhibition activity (IC(50) = 46.7 mug/ml). In the MMP-1 expression assay using RT-PCR, Typha orientalis (seed), Pyrrosia hastata (root), and Capsicum annum (whole plant) showed slightly lower inhibition activity than EGCG, which was used as a control. Furthermore, four extracts, including Persicaria hydropiper (whole plant), Filipendula glaberrima (root), Nymphaea tetragona (root), and Camellia japonica (leaf), completely inhibited the expression of MMP-1 in human fibroblast cells. The results showed that four of the 60 plant extracts may hold potential for use as natural active ingredients for anti-aging cosmetics.

Electron transfer from NADH bound to horse liver alcohol dehydrogenase (NAD+ dependent dehydrogenase): visualisation of the activity in the enzyme crystals and adsorption of formazan derivatives by these crystals

The crystals of holoenzyme from native and cross-linked alcohol dehydrogenase exhibit electron transfer from NADH to phenazinium methosulfate (PMS), and then to the tetrazolium salt sodium 3,3'-{1-[(phenylamino)carbonyl]-3,4-tetrazolium}-bis(4-methoxy-6-nitro)benzenesulfonate (XXT). The slow dissociation of the cofactor and/or the conformational change associated can now be bypassed. The reduction product, formazan, did not diffuse out of the crystals in buffer and the crystals turned colored. In the presence of dimethyl sulfoxide or dimethoxyethane, the formazan diffused out to the solution. The reaction rates were found to be, respectively, 18% and 15% of the redox reaction rate of ethanol with cinnamaldehyde, close to the activity determined for the enzyme in solution in the presence of dimethoxyethane. The use of system PMS-tetrazolium salt is a useful tool to visualize the activity of dehydrogenases and other electron transferring systems in the crystalline state. The adsorption of formazan by the alcohol dehydrogenase crystals occurs in solution.

Inhibition of respiratory syncytial virus in cultured cells by nucleocapsid gene targeted deoxyribozyme (DNAzyme)

Respiratory syncytial virus (RSV), which presents the primary cause of bronchiolitis and pneumonia among infants and causes significant morbidity and mortality in immunodeficient patients, remains a health problem worldwide. Unfortunately, an effective vaccine is currently unavailable and pharmacologic treatment needs further optimization for RSV disease. Because RSV is a non-segmented negative-strand RNA virus, it may be sensitive to the genome RNA cleaving by DNAzyme, an artificial nucleic acids molecule with high catalytic capability of cleaving complementary RNA molecules. Thus, RSV-targeted DNAzymes potentially present as a therapeutic candidate of RSV diseases. In this study, DNAzymes targeting the RSV genomic RNA or mRNA were designed and synthesized, one of which (DZn1133) did cleave RSV RNA in vitro, inhibit the transcription and expression of F viral gene, reduce the RSV yield by about 7 logs and protect more than 90% RSV-infected Hep-2 cells from a cytopathic effect at 8 microM. Moreover, 10 wild RSV strains isolated from clinic patients including both subgroups A and B were all suppressed by DZn1133 with greater anti-RSV activity than antisense DNA or ribavirin.

Adrenomedullin inhibits insulin exocytosis via pertussis toxin-sensitive G protein-coupled mechanism

Direct effects of adrenomedullin on insulin secretion from pancreatic beta-cells were investigated using a differentiated insulin-secreting cell line INS-1. Adrenomedullin (1-100 pM) inhibited insulin secretion at both basal (3 mM) and high (15 mM) glucose concentrations, although this inhibitory effect was not observed at higher concentrations of adrenomedullin. The inhibition of glucose-induced insulin secretion by adrenomedullin was restored with 12-h pretreatment with 1 microg/ml pertussis toxin (PTX), suggesting that this effect could be mediated by PTX-sensitive G proteins. Cellular glucose metabolism evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide colorimetric assay was not affected by adrenomedullin at concentrations that inhibited insulin secretion. Moreover, electrophysiological studies revealed that 10 pM adrenomedullin had no effect on membrane potential, voltage-gated calcium currents, or cytosolic calcium concentration induced by 15 mM glucose. Finally, insulin release induced by cAMP-raising agents, such as forskolin plus 3-isobutyl-1-methylxanthine or the calcium ionophore ionomycin, was significantly inhibited by 10 and 100 pM adrenomedullin. In conclusion, adrenomedullin at picomolar concentrations directly inhibited insulin secretion from beta-cells. This effect is likely due to the inhibition of insulin exocytosis through the activation of PTX-sensitive G proteins.

The surfactant sensitized analytical reaction of cerium(IV) with some triphenylformazan derivatives

Cationic surfactant, cetylpyridinium bromide (CPB), sensitizes the colour reaction of cerium(IV) with 1,3-o-hydroxyphenyl-5-phenylformazan(I), 1-m-hydroxyphenyl-3-o-hydroxyphenyl-5-phenylformazan(II) and 1-m-carboxyphenyl-3-o-hydroxyphenyl-5-phenylformazan(III). The formation of a soluble ternary complex of stoichiometric ratio 1:1:1 (Ce(IV)-R-CPB) is responsible for the observed enhancement in the molar absorptivity and Sandell sensitivity of the formed complex, when a surfactant is present. The ternary complex exhibits absorption maxima at 596, 571 and 607 nm (epsilon=6.05 x 10(4), 6.28 x 10(4) and 8.06 x 10(4)L mol(-1)cm(-1)) using triphenylformazan derivatives I, II and III, respectively. Beer's law is obeyed between 0.15 and 2.5 microg ml(-1), whereas, optimum concentration range applying Ringbom method is in the range 0.30-2.25 microg ml(-1). Conditional formation constants in the presence and absence of CPB for Ce(IV) complexes have been calculated. The proposed method has been successfully applied to the analysis of magnesium-base cerium alloys and synthetic mixtures corresponding to various cerium alloys.

Candidacidal activity of a monoclonal antibody that binds with glycosyl moieties of proteins of Candida albicans

The incidence of life threatening mycoses caused by opportunistic fungi has increased dramatically in recent years with Candida and Aspergillus being the most commonly encountered species. Candida albicans ranks among the four most common causes of bloodstream infections and is responsible for vulvovaginal candidiasis in the majority of women in their reproductive years. Limited spectrum of antifungal activity of currently available antifungals and emergence of resistance has become a serious problem. Therefore, in search of an alternative form of treatment of candidiasis, in the present study a monoclonal antibody (MAb-G5) of IgA isotype was identified from the hybridoma produced by the fusion of lymphocytes of C. albicans immunized mouse with Sp2/O cells. The MAb-G5 exhibited in vitro candidacidal activity and was also found to be useful for treatment and prophylactic use under experimental conditions in vivo.

Investigation of the effects of deracoxib and piroxicam on the in vitro viability of osteosarcoma cells from dogs

OBJECTIVE

To determine whether exposure of canine osteosarcoma cells to deracoxib or piroxicam results in decreased viability, whether the cytotoxic effects of deracoxib and piroxicam involve induction of apoptosis, and whether deracoxib is a more potent inhibitor of osteosarcoma cell growth than piroxicam.

SAMPLE POPULATION

1 fibroblast and 3 osteosarcoma cell lines.

PROCEDURE

Cell counts and viability assays were performed using osteosarcoma cells (POS, highly metastatic POS, and canine osteosarcoma cell 31) and fibroblasts after 72 hours of incubation with deracoxib at concentrations of 0.5 microM to 500 microM or piroxicam at concentrations of 1 microM to 1,000 microM. Percentage viability was determined for each concentration. A DNA fragmentation analysis was performed to assess drug-induced apoptosis.

RESULTS

Concentration of deracoxib required for 50% inhibition of cell viability (IC50) was reached in all 3 osteosarcoma cell lines and ranged from 70 to 150 microM, whereas the IC50 for piroxicam was only reached in the POS cell line at 500 microM. Neither deracoxib nor piroxicam induced sufficient toxicity in fibroblasts to reach an IC50. Exposure of osteosarcoma cells to cytotoxic concentrations of deracoxib and piroxicam did not result in DNA fragmentation.

CONCLUSIONS AND CLINICAL RELEVANCE

Intermediate and high concentrations of deracoxib and high concentrations of piroxicam were cytotoxic to osteosarcoma cells; neither drug inhibited cell viability at typical plasma concentrations in dogs. Deracoxib inhibited viability of cells at concentrations that did not affect fibroblast viability. There was no evidence of apoptosis induction for either drug; however, only 1 cell line was evaluated for apoptosis induction and only for a limited selection of drug concentrations.

Novel yeast cell dehydrogenase activity assay in situ

The aim of this research was to develop a suitable method of succinate dehydrogenase activity assay in situ for different industrial yeast strains. For this purpose different compounds: EDTA, Triton X-100, sodium deoxycholate, digitonin, nystatin and beta-mercaptoethanol were used. The permeabilization process was controlled microscopically by primuline staining. Enzyme assay was conducted in whole yeast cells with Na-succinate as substrate, phenazine methosulfate (PMS) as electron carrier and in the presence one of two different tetrazolium salts: tetrazolium blue chloride (BT) or cyanoditolyl tetrazolium chloride (CTC) reduced during the assay. In comparabile studies of yeast vitality the amount of intracellular ATP was determined according to luciferin/luciferase method. During the succinate dehydrogenase assay in intact yeast cells without permeabilization, BT formazans were partially visualized in the cells, but CTC formazans appeared to be totally extracellular or associated with the plasma membrane. Under these conditions there was no linear relationship between formazan color intensity signal and yeast cell density. From all chemical compounds tested, only digitonin was effective in membrane permeabilization without negative influence on cell morphology. Furthermore, with digitonin-treated cells a linear relationship between formazan color intensity signal and yeast cell number was noticed. Significant decreasing of succinate dehydrogenase activity and ATP content were observed during aging of the tested yeast strains.

Protective and detrimental effects of kaempferol in rat H4IIE cells: Implication of oxidative stress and apoptosis

Flavonoids are ubiquitous substances in fruits and vegetables. Among them, the flavonol kaempferol contributes up to 30% of total dietary flavonoid intake. Flavonoids are assumed to exert beneficial effects on human health, e.g., anticancer properties. For this reason, they are used in food supplements at high doses. The aim of this project was to determine the effects of kaempferol on oxidative stress and apoptosis in H4IIE rat hepatoma cells over a broad concentration range. Kaempferol is rapidly taken up and glucuronidated by H4IIE cells. The results demonstrate that kaempferol protects against H2O2-induced cellular damage at concentrations which lead to cell death and DNA strand breaks in the absence of H2O2-mediated oxidative stress. Preincubation with 50 microM kaempferol exerts protection against the loss of cell viability induced by 500 microM H2O2 (2 h) while the same concentration of kaempferol reduces cell viability by 50% in the absence of H2O2 (24 h). Preincubation with 50 microM kaempferol ameliorates the strong DNA damage induced by 500 microM H2O2 while 50 microM kaempferol leads to a significant increase of DNA breakage in the absence of H2O2. Preincubation with 50 microM kaempferol reduces H2O2-mediated caspase-3 activity by 40% (4 h) while the same concentration of kaempferol leads to the formation of a DNA ladder in the absence of H2O2 (24 h). It is concluded that the intake of high dose kaempferol in food supplements may not be advisable because in our cellular model protective kaempferol concentrations can also induce DNA damage and apoptosis by themselves.

Effect of GnRH analogs on the expression of TrkA and p75 neurotrophin receptors in primary cell cultures from human prostate adenocarcinoma

BACKGROUND

GnRH analogs have antiproliferative and/or apoptotic effects on prostate cancer cells. Also, neurotrophin receptors TrkA and p75 have been reported in normal prostate suggesting a role in the gland growth control. In prostate cancer, TrkA receptors seem to be overexpressed and p75 receptors show a decreased expression. These changes in neurotrophin receptors may be related with unbalanced growth in malignant cells. In the present study we investigate the effects of GnRH analogs (leuprolide and cetrorelix) on the expression of TrkA and p75 neurotrophin receptors in primary cultures of human prostate cancer cells.

METHODS

Tissue was obtained from radical prostatectomies due to prostate adenocarcinoma. Cells were isolated after sequential enzyme digestion and cultured in defined media. Nerve growth factor (NGF) receptors in untreated cultures were estimated by immunofluorescence. Cultures were treated with leuprolide (agonist) or cetrorelix (antagonist) and expression of TrkA and p75 receptors were evaluated by semi quantitative RT-PCR (polymerase chain reaction) and western blot. Cell proliferation was estimated by MTT method and apoptosis through COMET assay.

RESULTS

Both leuprolide and cetrorelix induced a significant increase in p75 receptor gene and protein expression at a concentration that induce apoptosis and decrease proliferation. TrkA receptors showed no changes in presence of GnRH analogs.

CONCLUSIONS

GnRH analogs, leuprolide, and cetrorelix, change the ratio between neurotrophin receptors TrkA and p75 by increasing gene and protein expression of p75 receptor. Considering that TrkA receptor is related with proliferation and p75 with apoptosis, we suggest that our findings may explain, in part, the effect of GnRH analogs on prostate cancer growth.

Ligands for the peroxisome proliferator-activated receptor-gamma have inhibitory effects on growth of human neuroblastoma cells in vitro

The thiazolidinedione (TZD) or glitazone class of peroxisome proliferator-activated-gamma (PPAR-gamma) ligands not only induce adipocyte differentiation and increase insulin sensitivity, but also exert growth inhibitory effects on several carcinoma cell lines in vitro as well as in vivo. In the current study the in vitro effect of four PPAR-gamma agonists (ciglitazone, pioglitazone, troglitazone, rosiglitazone) on the cell growth of seven human neuroblastoma cell lines (Kelly, LAN-1, LAN-5, LS, IMR-32, SK-N-SH, SH-SY5Y) was investigated. Growth rates were assessed by a colorimetric XTT-based assay kit. Expression of PPAR-gamma protein was examined by immunohistochemistry and Western blot analysis. All glitazones inhibited in vitro growth and viability of the human neuroblastoma cell lines in a dose-dependent manner showing considerable effects only at high concentrations (10 microM and 100 microM). Effectiveness of the glitazones on neuroblastoma cell growth differed depending on the cell line and the agent. The presence of PPAR-gamma protein was demonstrated in all cell lines. Our findings indicate that ligands for PPAR-gamma may be useful therapeutic agents for the treatment of neuroblastoma. Thus the effect of glitazones on the growth of neuroblastoma should now be investigated in an in vivo animal model.

Nucleation-dependent polymerization is an essential component of amyloid-mediated neuronal cell death

Accumulating evidence suggests that amyloid protein aggregation is pathogenic in many diseases, including Alzheimer's disease. However, the mechanisms by which protein aggregation mediates cellular dysfunction and overt cell death are unknown. Recent reports have focused on the potential role of amyloid oligomers or protofibrils as a neurotoxic form of amyloid-beta (Abeta) and related amyloid aggregates. Here we describe studies indicating that overt neuronal cell death mediated by Abeta(1-40) is critically dependent on ongoing Abeta(1-40) polymerization and is not mediated by a single stable species of neurotoxic aggregate. The extent and rate of neuronal cell death can be controlled by conditions that alter the rate of Abeta polymerization. The results presented here indicate that protofibrils and oligomeric forms of Abeta most likely generate neuronal cell death through a nucleation-dependent process rather than acting as direct neurotoxic ligands. These findings bring into question the use of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide formazan assay (MTT assay) as a reporter of Abeta-mediated neuronal cell death and suggest that diffusible Abeta protofibrils and oligomers more likely mediate subtle alterations of synaptic function and long-term potentiation rather than overt neuronal cell death. These results have been extended to Abeta(1-42), the non-Abeta component of Alzheimer's disease amyloid plaques, and human amylin, suggesting that nucleation-dependent polymerization is a common mechanism of amyloid-mediated neuronal cell death. Our findings indicate that ongoing amyloid fibrillogenesis may be an essential mechanistic process underlying the pathogenesis associated with protein aggregation in amyloid disorders.

Comparative study of cytotoxicity and oxidative stress induced by deoxynivalenol, zearalenone or fumonisin B1 in human intestinal cell line Caco-2

Fusarium species infestations of cereals crops occur worldwide. Fusarium toxins such as, deoxynivalenol (DON), zearalenone (ZEN) and fumonisin B1 (FB1) have been shown to cause diverse toxic effects in animals and also suspected of disease causation in humans. From the literature and mechanistic point of view, DON binds to the ribosomal peptidyl-transferase and inhibits protein synthesis specifically and DNA synthesis consequently. ZEN known to be genotoxic, binds to 17-beta-estradiol receptors, induces lipid peroxidation, cell death and inhibits protein and DNA synthesis. FB1 disrupts sphingolipid metabolism, induces lipid peroxidation altering the cell membrane and causing cell death. We intended to compare DON, ZEN and FB1 (1-150 microM) cytotoxic effect and the pathways leading to cell death and related to oxidative stress and macromolecules syntheses in a human intestinal cell line in order to tentatively classify them according to their respective potential toxicity. The comparison reveals that all three mycotoxins bear, at variable degree, the capability of inducing lipid peroxidation (MDA production) and could be classified above 10 microM in decreasing potency order FB1>DON>ZEN. This effect seems to be related to their common target that is the mitochondria as revealed by MTT test and seemingly not related to sphingoids accumulation concerning FB1. DON and ZEN also adversely affect lysosomes in contrast to FB1. The three mycotoxins inhibit protein synthesis with respective IC50 of 5, 8.8 and 19 microM for DON, FB1 and ZEN confirming that protein synthesis is a specific target of DON. DNA synthesis is inhibited by DON, ZEN and FB1 with respective IC50 of 1.7, 10 and 20 microM. However at higher concentrations DNA synthesis seems to be restored for FB1 and DON suggesting a promoter activity. Altogether the potency of the three mycotoxins in macromolecules inhibition is DON>ZEN>FB1 in Caco-2 cells. It appears then that FB1 acts rather through lipid peroxidation while DON affects rather DNA and protein synthesis.

Ultrafine titanium dioxide particles in the absence of photoactivation can induce oxidative damage to human bronchial epithelial cells

Ultrafine titanium dioxide (TiO(2)) particles have been shown to exhibit strong cytotoxicity when exposed to UVA radiation, but are regarded as a biocompatible material in the absence of photoactivation. In contrast to this concept, the present results indicate that anatase-sized (10 and 20 nm) TiO(2) particles in the absence of photoactivation induced oxidative DNA damage, lipid peroxidation, and micronuclei formation, and increased hydrogen peroxide and nitric oxide production in BEAS-2B cells, a human bronchial epithelial cell line. However, the treatment with anatase-sized (200 and >200 nm) particles did not induce oxidative stress in the absence of light irradiation; it seems that the smaller the particle, the easier it is for the particle to induce oxidative damage. The photocatalytic activity of the anatase form of TiO(2) was reported to be higher than that of the rutile form. In contrast to this notion, the present results indicate that rutile-sized 200 nm particles induced hydrogen peroxide and oxidative DNA damage in the absence of light but the anatase-sized 200nm particles did not. In total darkness, a slightly higher level of oxidative DNA damage was also detected with treatment using an anatase-rutile mixture than with treatment using either the anatase or rutile forms alone. These results suggest that intratracheal instillation of ultrafine TiO(2) particles may cause an inflammatory response.