Optimization of the tetrazolium-based colorimetric assay for the measurement of cell number and cytotoxicity

Essential oil and furanosesquiterpenes from myrrh oleo-gum resin: a breakthrough in mosquito vector management

Mosquitoes (Diptera: Culicidae) are vectors of various pathogens of public health concern and replacing conventional insecticides remains a challenge. In this regard, natural products represent valuable sources of potential insecticidal compounds, thus increasingly attracting research interest. Commiphora myrrha (T.Nees) Engl. (Burseraceae) is a medicinal plant whose oleo-gum resin is used in food, cosmetics, fragrances, and pharmaceuticals. Herein, the larvicidal potential of its essential oil (EO) was assessed on four mosquito species (Aedes albopictus Skuse, Aedes aegypti L., Anopheles gambiae Giles and Anopheles stephensi Liston), with LC50 values ranging from 4.42 to 16.80 μg/mL. The bio-guided EO fractionation identified furanosesquiterpenes as the main larvicidal compounds. A GC-MS-driven untargeted metabolomic analysis revealed 32 affected metabolic pathways in treated larvae. The EO non-target toxicity on Daphnia magna Straus (LC50 = 4.51 μL/L) and its cytotoxicity on a human kidney cell line (HEK293) (IC50 of 14.38 μg/mL) were also assessed. This study shows the potential of plant products as innovative insecticidal agents and lays the groundwork for the possible exploitation of C. myrrha EO in sustainable approaches for mosquito management.

Hyaluronic Acid-Conjugated Thermoresponsive Polymer-Based Bioformulation Enhanced Wound Healing and Gut Barrier Repair of a TNBS-Induced Colitis Injury Ex Vivo Model in a Dynamic Perfusion Device

Impairment of intestinal epithelium is a typical feature of inflammatory bowel disease (IBD) that causes leakage of bacteria and antigens from the intestinal lumen and thus results in persistent immune activation. Hence, healing and regeneration of the damaged gut mucosa is a promising therapeutic approach to achieve deep remission in IBD. Currently, available systemic therapies have moderate effects and are often associated with numerous side effects and malignancies. In this study, we aimed to develop a topical therapy by chemically conjugating a temperature-responsive polymer, i.e., poly(N-isopropylacrylamide), along with hyaluronic acid to obtain a sprayable therapeutic formulation that upon colon instillation adheres to the damaged gut mucosa due to its temperature-induced phase transition and mucoadhesive properties. An ex vivo adhesion experiment demonstrates that this therapeutic formulation forms a thin physical coating on the mucosal lining at a physiological temperature within 5 min. Physicochemical characterization of (P(NIPAM-co-NTBAM)-HA) established this formulation to be biocompatible, hemo-compatible, and non-immunogenic. Prednisolone was encapsulated within the polymer formulation to achieve maximum therapeutic efficacy in the case of IBD-like conditions as assessed in a custom-fabricated perfusion-based ex vivo model system. Histological analysis suggests that the prednisolone-encapsulated polymer formulation nearly restored the mucosal architecture after 2,4,6-trinitrobenzenesulfonic acid-induced damage. Furthermore, a significant (p ≤ 0.001) increase in mRNA levels of Muc-2 and ZO-1 in treated groups further confirmed the mucosal epithelial barrier restoration.

Tumor Chemosensitivity Assays Are Helpful for Personalized Cytotoxic Treatments in Cancer Patients

Tumor chemosensitivity assays (TCAs), also known as drug response assays or individualized tumor response tests, have been gaining attention over the past few decades. Although there have been strong positive correlations between the results of these assays and clinical outcomes, they are still not considered routine tests in the care of cancer patients. The correlations between the assays' results (drug sensitivity or resistance) and the clinical evaluations (e.g., response to treatment, progression-free survival) are highly promising. However, there is still a need to design randomized controlled prospective studies to secure the place of these assays in routine use. One of the best ideas to increase the value of these assays could be the combination of the assay results with the omics technologies (e.g., pharmacogenetics that gives an idea of the possible side effects of the drugs). In the near future, the importance of personalized chemotherapy is expected to dictate the use of these omics technologies. The omics relies on the macromolecules (Deoxyribonucleic acid -DNA-, ribonucleic acid -RNA-) and proteins (meaning the structure) while TCAs operate on living cell populations (meaning the function). Therefore, wise combinations of TCAs and omics could be a highly promising novel landscape in the modern care of cancer patients.

The MTT viability assay yields strikingly false-positive viabilities although the cells are killed by some plant extracts

The MTT assay is one of the often used cell viability/cytotoxicity assays. However, when the methanol extracts of plants are used to test their cytotoxic potential, interference may occur, resulting in false-positive viability results. Therefore, in this study, the reliability of the MTT assay was investigated in the case of plant use. The methanol extracts of three different plants (Hypericum adenotrichum, Salvia kronenburgii, and Pelargonium quercetorum) were tested in breast cancer cell lines (MCF-7 and MDA-MB-231) using the MTT assay and the results were compared to the ATP assay, which is a much more sensitive and reliable assay due to its interference-free feature. Additionally, decreased cell density was confirmed with phase-contrast microscopy and fluorescence staining (Hoechst 33342 dye). Although both of the viability/cytotoxicity assays are considered as metabolic assays, viabilities (in %) in the MTT assay were found to be strikingly higher when compared to the results with the ATP assay. Even in the case of total death, the MTT assay still produced artificial/false increases in viability. The morphology-based evaluation of viability/cytotoxicity by phase-contrast microscopy and Hoechst 33342 staining were greatly compatible with the ATP assay results. Overestimated (false) viabilities in the MTT assay suggests a serious interference between the MTT assay itself and the extracts used. Some ingredients of plants may have reducing activity (like the dehydrogenase activity of the cells) that converts the MTT compound into the colored formazan that is the principle of the assay. Therefore, the MTT assay may not be a suitable assay for some plant extracts, urging great caution when plants are used.

New water-soluble polypyridine silver(I) derivatives of 1,3,5-triaza-7-phosphaadamantane (PTA) with significant antimicrobial and antiproliferative activities

The new series of silver(I) coordination polymers [Ag(N-N)(μ-PTA)]n(X)n (1, 2, 4-8, 10, 11) and discrete monomers [Ag(N-N)(PTA)2](X) (3, 9) {N-N = bpy (1-3), dtbpy (4), neocup (5, 6), phen (7-9), dione (10, 11); X = NO3 (1, 3, 5, 7, 9, 10), PF6 (2, 4, 6, 8, 11)} were generated by self-assembly reactions, in MeOH at ~25 °C, of AgNO3 or AgPF6 with 1,3,5-triaza-7-phosphaadamantane (PTA) and the corresponding polypyridines, namely 2,2'-bipyridine (bpy), 4,4'-di-tert-butyl-2,2'-bipyridine (dtbpy), 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (neocup) and 1,10-phenanthroline-5,6-dione (dione). The compounds were obtained as air and light stable solids and characterized by IR, (1)H and (31)P{(1)H} NMR spectroscopy, ESI(+)-MS and elemental analyses. The crystal structure of 1 was determined by single crystal X-ray diffraction analysis, revealing infinite one-dimensional (1D) linear chains driven by μ-PTA N,P-linkers. Apart from representing the first examples of the metal-PTA derivatives bearing polypyridine ligands, 1-11 also feature solubility in water (S(25°C) ≈ 4-18 mg mL(-1)). Selected compounds (1, 3, 5, 7, 9 and 10) were thus tested for their biological properties and found to exhibit significant antibacterial and antifungal activities, screened in vitro against the standard strains of Staphylococcus aureus, Staphylococcus pyogenes, Staphylococcus pneumoniae, Staphylococcus sanguinis, Staphylococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Furthermore, the compounds 5, 7, 9 and 10 show a pronounced antiproliferative activity against human malignant melanoma (A375), and the effects on the inhibition of tumor cells in vitro are in agreement with the DNA-binding studies.

Chemical composition and in vitro biological activities of the essential oil of Vepris macrophylla (BAKER) I.VERD. endemic to Madagascar

Vepris macrophylla is an evergreen tree occurring in sub-humid forest of Madagascar and traditionally used in the Island to treat several complaints as well as to prepare aromatic teas and alcoholic drinks. In the present work, the essential oil distilled from the leaves was analyzed for the first time by gas chromatography (GC-FID) and gas chromatography/mass spectrometry (GC/MS). The major compounds were citral (56.3%), i.e., mixture of neral (23.1%) and geranial (33.2%), citronellol (14.5%), and myrcene (8.3%). The essential oil exhibited antimicrobial activity against S. aureus, P. aeruginosa, and C. albicans as determined by vapor-diffusion assay, supporting the traditional use of the plant for preparing steam bath for the treatment of infectious diseases. The essential oil was evaluated for cytotoxic activity on human tumor cell lines by MTT (=3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay, showing inhibitory effects comparable to those of cisplatin, notably on MDA-MB 231 (human breast adenocarcinoma) and HCT116 (human colon carcinoma) cell lines. Finally, the essential oil was also subjected to screening for its antioxidant activity and the free radical scavenging capacity.

Bioactive selaginellins from Selaginella tamariscina (Beauv.) Spring

A new selaginellin named selaginellin O (1), along with three other known selaginellins (2–4) were isolated from Selaginella tamariscina (Beauv.) Spring. On the basis of spectroscopic analysis, the structure of selaginellin O was demonstrated to be 4-[(4’-hydroxy-4-formyl-3-((4-hydroxyphenyl)ethynyl)biphenyl-2-yl)(4-hydroxyphenyl)methylene]cyclohexa-2,5-dien-1-one. Compound 1, 2 and 3 exhibited appreciable cytotoxic activity against cultured HeLa cells (human cervical carcinoma cells), as well as significant antioxidant activity.

Antitumor and immunomodulatory activity of polysaccharides from Sargassum fusiforme

Sargassum fusiforme (Harv.) Setchel is an ingredient of Chinese herbal medicine that has been applied for thousands of years. This study was set up to evaluate the in vivo and in vitro anti-tumor potential of the polysaccharide (SFPS) from S. fusiforme and the immune response in tumor-bearing mice. SFPS was isolated by hot water extraction and ethanol precipitation. The mice inoculated with A549 cells were orally administrated with SFPS at the doses of 100 and 200mg/kg body weight for 28 days. The effects on the growth of tumor, serum TNF-α level, splenocyte proliferation, production of cytokines from peritoneal macrophages in A549-bearing mice were measured. Meanwhile, the cytotoxicity of SFPS on A549 cell line was also studied. Results showed that SFPS could not only significantly inhibit the growth of A549 lung adenocarcinoma in mice, but also remarkably promote IL-1 and TNF-α production from peritoneal macrophages, serum TNF-α level, and splenocytes proliferation in A549-bearing mice. The results indicate that SFPS has anti-tumor properties in vivo and in vitro, and improves the immune response in tumor-bearing mice. It could act as anti-tumor agent with immunomodulatory activity.

Novel 3-oxo- and 3,24-dinor-2,4-secooleanane-type triterpenes from Terminalia ivorensis A. Chev

Two new oleanane-type triterpenes named ivorengenin A (=3-oxo-2α,19α,24-trihydroxyolean-12-en-28-oic acid; 1) and ivorengenin B (=4-oxo-19α-hydroxy-3,24-dinor-2,4-secoolean-12-ene-2,28-dioic acid; 2), together with five known compounds, arjungenin, arjunic acid, betulinic acid, sericic acid, and oleanolic acid, were isolated from the barks of Terminalia ivorensis A. Chev. (Combretaceae). Their structures were established on the basis of 1D- and 2D-NMR data, and mass spectrometry. A biogenetic pathway to the formation of these compounds from sericic acid, isolated as the major compound from this plant, was proposed. The antioxidant activities of different compounds were investigated by means of the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, and IC(50) values were calculated and compared with Trolox activity. Antiproliferative activities of the isolated compounds were also evaluated against MDA-MB-231, PC3, HCT116, and T98G human cancer cell lines, against which the compounds showed significant cytotoxic activities.

Synthesis, antimicrobial and antiproliferative activity of novel silver(I) tris(pyrazolyl)methanesulfonate and 1,3,5-triaza-7-phosphadamantane complexes

Five new silver(I) complexes of formulas [Ag(Tpms)] (1), [Ag(Tpms)(PPh(3))] (2), [Ag(Tpms)(PCy(3))] (3), [Ag(PTA)][BF(4)] (4), and [Ag(Tpms)(PTA)] (5) {Tpms = tris(pyrazol-1-yl)methanesulfonate, PPh(3) = triphenylphosphane, PCy(3) = tricyclohexylphosphane, PTA = 1,3,5-triaza-7-phosphaadamantane} have been synthesized and fully characterized by elemental analyses, (1)H, (13)C, and (31)P NMR, electrospray ionization mass spectrometry (ESI-MS), and IR spectroscopic techniques. The single crystal X-ray diffraction study of 3 shows the Tpms ligand acting in the N(3)-facially coordinating mode, while in 2 and 5 a N(2)O-coordination is found, with the SO(3) group bonded to silver and a pendant free pyrazolyl ring. Features of the tilting in the coordinated pyrazolyl rings in these cases suggest that this inequivalence is related with the cone angles of the phosphanes. A detailed study of antimycobacterial and antiproliferative properties of all compounds has been carried out. They were screened for their in vitro antimicrobial activities against the standard strains Enterococcus faecalis (ATCC 29922), Staphylococcus aureus (ATCC 25923), Streptococcus pneumoniae (ATCC 49619), Streptococcus pyogenes (SF37), Streptococcus sanguinis (SK36), Streptococcus mutans (UA159), Escherichia coli (ATCC 25922), and the fungus Candida albicans (ATCC 24443). Complexes 1-5 have been found to display effective antimicrobial activity against the series of bacteria and fungi, and some of them are potential candidates for antiseptic or disinfectant drugs. Interaction of Ag complexes with deoxyribonucleic acid (DNA) has been studied by fluorescence spectroscopic techniques, using ethidium bromide (EB) as a fluorescence probe of DNA. The decrease in the fluorescence of DNA-EB system on addition of Ag complexes shows that the fluorescence quenching of DNA-EB complex occurs and compound 3 is particularly active. Complexes 1-5 exhibit pronounced antiproliferative activity against human malignant melanoma (A375) with an activity often higher than that of AgNO(3), which has been used as a control, following the same order of activity inhibition on DNA, i.e., 3 > 2 > 1 > 5 > AgNO(3)≫ 4.

New flow cytometric assays for monitoring cell-mediated cytotoxicity

The exact immunologic responses after vaccination that result in effective antitumor immunity have not yet been fully elucidated and the data from ex vivo T-cell assays have not yet defined adequate surrogate markers for clinical efficacy. A more detailed knowledge of the specific immune responses that correlate with positive clinical outcomes should help to develop better or novel strategies to effectively activate the immune system against tumors. Furthermore, clinically relevant material is often limited and, thus, precludes the ability to perform multiple assays. The two main assays currently used to monitor lymphocyte-mediated cytoxicity in cancer patients are the (51)Cr-release assay and IFN-gamma ELISpot assay. The former has a number of disadvantages, including low sensitivity, poor labeling and high spontaneous release of isotope from some tumor target cells. Additional problems with the (51)Cr-release assay include difficulty in obtaining autologous tumor targets, and biohazard and disposal problems for the isotope. The ELISpot assays do not directly measure cytotoxic activity and are, therefore, a surrogate marker of cyotoxic capacity of effector T cells. Furthermore, they do not assess cytotoxicity mediated by the production of the TNF family of death ligands by the cytotoxic cells. Therefore, assays that allow for the simultaneous measurement of several parameters may be more advantageous for clinical monitoring. In this respect, multifactor flow cytometry-based assays are a valid addition to the currently available immunologic monitoring assays. Use of these assays will enable detection and enumeration of tumor-specific cytotoxic T lymphocytes and their specific effector functions and any correlations with clinical responses. Comprehensive, multifactor analysis of effector cell responses after vaccination may help to detect factors that determine the success or failure of a vaccine and its immunological potency.

Rheediinosides A and B, two antiproliferative and antioxidant triterpene saponins from Entada rheedii

Two triterpenoid saponins have been isolated from the seed kernels of Entada rheedii. Their structures have been established using 1D- and 2D-NMR and mass spectrometry as 3-O-beta-D-xylopyranosyl-(1-->3)-O-alpha-l-arabinopyranosyl-(1-->6)-2-acetylamino-2-deoxy-beta-D-glucopyranosylentagenic acid 28-O-beta-apiofuranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (Rheediinoside A, 1) and 3-O-beta-D-glucopyranosyl-(1-->3)-O-[beta-D-xylopyranosyl-(1-->3)-alpha-l-arabinopyranosyl-(1-->6)]-2-acetylamino-2-deoxy-beta-D-glucopyranosylentagenic acid 28-O-beta-apiofuranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (Rheediinoside B, 2). Compounds 1 and 2 were tested for their antiproliferative activity against T98G, A431, PC3 and B16-F1 cell lines, and further for their antioxidant properties. Moderate cytotoxic potency and antioxidant properties were found for these compounds whereas Rheediinoside B was in all assays more active than Rheediinoside A.

Imunomodulative effect of liposomized muramyltripeptide phosphatidylethanolamine (L-MTP-PE) on mice with alveolar echinococcosis and treated with albendazole

The effect of liposomized muramyltripeptide phosphatidylethanolamine (L-MTP-PE) administered separately or with anthelmintic albendazole (ABZ) on cellular immunity of mice with alveolar echinococcosis was studied. The proliferative activity of splenic T and B lymphocytes was the most stimulated after combined L-MTP-PE + ABZ therapy [from weeks 8 to 14 post-infection (p.i.)] that also induced a long-term development of protective Th1 response (the highest serum concentration of IFN-gamma from weeks 8 to 18 p.i.). On the contrary, Th2 response (cytokine IL-5) in infected mice treated with L-MTP-PE was inhibited since week 8 p.i., but a significant long-term decrease in IL-5 concentration was found after combined L-MTP-PE+ABZ therapy until the end of the experiment (until week 26 p.i.). L-MTP-PE stimulated the production of superoxide anion (O2-) by peritoneal macrophages from weeks 8 to 12 p.i., but the highest O2- production was accordingly recorded after therapy L-MTP-PE+ABZ from weeks 8 to 18 p.i. Stimulation of cellular immunity of mice with alveolar echinococcis with L-MTP-PE and an interaction with ABZ's anti-parasitic effect resulted in the greatest and long-term reduction of growth of Echinococcus multilocularis cysts in the host from week 10 p.i. until the end of the experiment.

Immunomodulative effect of glucan and/or glucan supplemented with zinc in albendazole therapy for murine alveolar echinococcosis

The effect of glucan immunomodulator (GI) and glucan supplemented with zinc (GIZn) administered separately or with albendazole (ABZ) on cellular immunity of mice with alveolar echinococcosis was observed. The stimulative effect of GI and GI + ABZ therapy on proliferative response of T lymphocytes was prolonged by GIZn or GIZn + ABZ from week 6 to 14 postinfection (p.i.). The increased proliferation of B lymphocytes was observed during combined therapies GI + ABZ and GIZn + ABZ from week 6 to 12 p.i. Number of splenic CD4 T cells in mice with GI or GI + ABZ therapy was increased only on weeks 6 and 8 p.i. GIZn and GIZn + ABZ therapy prolonged this stimulation from week 6 to 14 p.i. Serum concentration of interferon-gamma (IFN-gamma) was increased after GIZn therapy and reduced after GI therapy from week 8 to 12 p.i. GIZn + ABZ therapy had the highest effect on the IFN-gamma rise from week 8 to 22 p.i. Both GI and GIZn inhibited the serum concentration of interleukin-5 (IL-5) from week 6 p.i. The production of superoxide anion was increased after GI therapy from week 6 to 14 p.i. and after GI + ABZ or GIZn + ABZ therapies from week 12 to 18 p.i. The most effective antiparasitic therapy for alveolar echinococcosis was reached by GIZn + ABZ therapy.

Nrf2 regulates an adaptive response protecting against oxidative damage following diquat-mediated formation of superoxide anion

Mouse embryonic fibroblasts derived from Nrf2-/- mice (N0) and Nrf2+/+ mice (WT) have been used to characterize both basal and diquat (DQ)-induced oxidative stress levels and to examine Nrf2 activation during exposure to DQ-generated superoxide anion. Microarray analysis revealed that N0 cells have similar constitutive mRNA expression of genes responsible for the direct metabolism of reactive oxygen species but decreased expression of genes responsible for the production of reducing equivalents, repair of oxidized proteins and defense against lipid peroxidation, compared to WT cells. Nonetheless, the basal levels of ROS flux and oxidative damage biomarkers in WT and N0 cells were not different. Diquat dibromide (DQ), a non-electrophilic redox cycling bipyridylium herbicide, was used to generate intracellular superoxide anion. Isolated mitochondria from both cell lines exposed to DQ produced equivalent amounts of ROS, indicating a similar cellular capacity to generate ROS. However, N0 cells exposed to DQ for 24-h exhibited markedly decreased cell viability and aconitase activity as well as increased lipid peroxidation and glutathione oxidation, relative to WT cells. 2',7'-Dichlorofluorescein fluorescence was not increased in WT and N0 cells after 30-min of DQ exposure. However, increased levels of ROS were detected in N0 cells but not WT cells after 13-h of DQ treatment. Additionally, total glutathione concentrations increased in WT, but not N0 cells following a 24-h exposure to DQ. DQ exposure resulted in activation of an antioxidant response element-luciferase reporter gene, as well as induction of Nrf2-regulated genes in WT, but not N0 cells. Thus the enhanced sensitivity of N0 cells does not reflect basal differences in antioxidative capacity, but rather an impaired ability to mount an adaptive response to sustained oxidative stress.

Crocetin inhibits leukocyte adherence to vascular endothelial cells induced by AGEs

Advance glycation end products (AGEs) have been postulated to play an important role in diabetic complications such as atherosclerosis disease. Adhesion and migration of leukocyte to endothelial cells (EC) is one of the early key steps in the pathogenesis. Crocetin is an important ingredient of diet in India and also used in various systems of indigenous medicine. In this study, we investigated effect of crocetin on leukocyte adherence to bovine endothelial cells (BEC) induced by AGEs in vitro and the possible mechanisms involved. BEC were pre-incubated with crocetin (0.01, 0.1, and 1 microM) for 12 h and exposed to AGEs (100 microg/ml). Cells proliferation was determined by MTT; leukocyte-endothelial cell adhesion was assayed by myeloperoxidase methods; intercellular adhesion molecular-1 (ICAM-1) protein expression was studied by immunocytochemistry and mitochondrial membrane potential (MMP) was analyzed by the retention of rhodamine 123 (RH123); furthermore, levels of anion (O(2)(-)), malonicdialdehyde (MDA) in super cells culture and superoxide dismutase (SOD) in cells were also detected, respectively. Results demonstrated that crocetin could inhibit AGE-induced BEC growth suppression and significantly reduce adhesion rate of leukocyte to BEC (P < 0.01 or P < 0.05); ICAM-1 protein was also suppressed (P < 0.05). Furthermore, crocetin could increase activity of SOD (P < 0.05), decrease levels of MDA and O(2)(-) (P < 0.01). In addition, down-regulated MMP was also increased by crocetin (P < 0.01 or P < 0.05). These data revealed crocetin could prevent the adhesion of leukocyte to BEC and down-regulation the expression of ICAM-1, and the possible mechanisms might be related to its antioxidant activity, which is through up-regulation of the activity of antioxidant enzymes and protection for mitochondrion.

Anti-cancer effect and structural characterization of endo-polysaccharide from cultivated mycelia of Inonotus obliquus

The endo-polysaccharide extracted from mycelia of Inonotus obliquus (Pers.:Fr.) Pil. (Hymenochaetaceae) is a specific activator of B cells and macrophages. However, the in vivo anti-cancer effects and the chemical structure of the endo-polysaccharide are unknown. We purified the endo-polysaccharide, investigated its anti-cancer effects via in vitro and in vivo assays, and performed a structural characterization. The endo-polysaccharide was extracted from I. obliquus mycelia cultivated in a 300-l pilot fermenter, followed by hot water extraction and ethanol precipitation. Purification was achieved by DEAE-cellulose ion-exchange chromatography and gel-permeation chromatography. Chemical analysis revealed that the purified endo-polysaccharide is an alpha-linked fucoglucomannan with a molecular weight of approximately 1,000 kDa. The anti-cancer activities of the endo-polysaccharide against various types of tumor cells were determined. No direct toxicity against either cancer or normal cells was observed. Intraperitoneal administration of the endo-polysaccharide significantly prolonged the survival rate of B16F10-implanted mice, resulting in a 4.07-fold increase in the survival rate at a dose of 30 mg/kg/day. After 60 days of feeding, approximately 67% of the initial number of mice survived with no tumor incidence based on macroscopic examination. These results indicate that the anti-cancer effect of endo-polysaccharide is not directly tumorcidal but rather is immuno-stimulating.

In vivo and in vitro anti-inflammatory and anti-nociceptive effects of the methanol extract of Inonotus obliquus

The mushroom Inonotus obliquus (Fr.) Pilát (Hymenochaetaceae), has been traditionally used for the treatment of gastrointestinal cancer, cardiovascular disease and diabetes in Russia, Poland and most of Baltic countries. This study was designed to investigate the anti-inflammatory and anti-nociceptive effects of the methanol extract from Inonotus obliquus (MEIO) in vivo and in vitro. MEIO (100 or 200 mg/(kgday), p.o.) reduced acute paw edema induced by carrageenin in rats, and showed analgesic activity, as determined by an acetic acid-induced abdominal constriction test and a hot plate test in mice. To reveal the mechanism of the anti-inflammatory effect of MEIO, we examined its effect on lipopolysaccharide (LPS)-induced responses in a murine macrophage cell line RAW 264.7. MEIO was found to significantly inhibit the productions of nitric oxide (NO), prostaglandin E2 (PGE2) and tumor necrosis factor-alpha (TNF-alpha) in LPS-stimulated RAW 264.7 macrophages. Consistent with these observations, MEIO potently inhibited the protein and mRNA expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, MEIO inhibited the LPS-induced DNA binding activity of nuclear factor-kappaB (NF-kappaB), and this was associated with the prevention of inhibitor kappaB degradation and a reduction in nuclear p65 protein levels. Taken together, our data indicate that the anti-inflammatory and anti-nociceptive properties of MEIO may be due to the inhibition of iNOS and COX-2 expression via the down-regulation of NF-kappaB binding activity.

Quantitative reduction of methyl tetrazolium by fresh vein homograft biopsies in vitro is an index of viability

OBJECTIVE

The color density of the methyl tetrazolium (MTT) test is proportional to mitochondrial enzyme activity thus reflecting cellular viability. The aim was to evaluate the MTT test as a viability assay for vein homograft studies.

MATERIALS AND METHODS

Fresh intact vein samples were harvested during multi-organ procurement. The reliability of the MTT assay was tested by a fluorescent dye combination (1 microg/ml propidium iodide PI and 4 microM/ml SYTO-16 stains). The enzyme kinetics of the reaction was also investigated. The optimal reagent concentration, biopsy size and incubation period were established.

RESULTS

There was a linear relationship between the vein homograft's weight and the pigment production activity. A nonspecific reaction (8.6%) was observed in negative controls. The MTT cleavage up to 0.1% (w/v) follows the Michaelis kinetics. The Michaelis constant (2,805 +/- 130 microM), the maximal velocity (196 +/- 2.2 x 10(-5 )microM s(-1)) and the velocity constant (6.98 +/- 0.2 x 10(-7) s(-1)) was calculated. The viability assessed by fluorescent dyes simultaneously visualized the live/dead cell ratio, which can be calculated by image analysis software.

CONCLUSION

The use of MTT in colorimetric assays offers high sensitivity. The assay is simple, inexpensive, and reproducible in vein homograft studies.

Comparison of the usefulness of the MTT, ATP, and calcein assays to predict the potency of cytotoxic agents in various human cancer cell lines

Cell viability assays are important tools in oncological research and clinical practice to assess the tumor cell sensitivity of individual patients. The purpose of this study was to demonstrate the comparability of 3 widely used assays (MTT, ATP, calcein assays) by principal component analysis. The study included 4 different cytostatics (cisplatin, docetaxel, doxorubicin, vinblastine) and 3 different human cancer cell lines (MCF-7, A2780, doxorubicin resistant A2780adr). Ninety-three percent of the total variance of all variables included in the principal component analysis (resulting from 3 cell lines and 3 assays) could be explained by 1 principal component. Factor loadings were > 0.937 except for the variable MTT-A2780adr, which was 0.872. These results indicate the similarity of the 3 assays. A 2nd principal component analysis included literature data and showed accordance of data from this study and the literature. The MTT assay was further improved as a high-throughput screening-capable assay. The ATP assay is able to detect effects of cytostatics already after 1 h incubation. The determination of resistance factors allowed to differentiate cytostatics into P-gp or non-P-gp substrates. In conclusion, this study provides improved microplate reader-based cell viability assays and sets a statistically solid basis for a future comparison of data obtained in different laboratories by any of the 3 assays.

Intermediate-conductance Ca2+-activated K+ channel is expressed in C2C12 myoblasts and is downregulated during myogenesis

We report here the expression in C2C12 myoblasts of the intermediate-conductance Ca2+-activated K+ (IK(Ca)) channel. The IK(Ca) current, recorded under perforated-patch configuration, had a transient time course when activated by ionomycin (0.5 microM; peak current density 26.2 +/- 3.7 pA/pF; n = 10), but ionomycin (0.5 microM) + 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one (100 microM) evoked a stable outward current (28.4 +/- 8.2 pA/pF; n = 11). The current was fully inhibited by charybdotoxin (200 nM), clotrimazole (2 microM), and 5-nitro-2-(3-phenylpropylamino)benzoic acid (300 microM), but not by tetraethylammonium (1 mM) or D-tubocurarine (300 microM). Congruent with the IK(Ca) channel, elevation of intracellular Ca2+ in inside-out patches resulted in the activation of a voltage-insensitive K+ channel with weak inward rectification, a unitary conductance of 38 +/- 6 pS (at negative voltages), and an IC50 for Ca2+ of 530 nM. The IK(Ca) channel was activated metabotropically by external application of ATP (100 microM), an intracellular Ca2+ mobilizer. Under current-clamp conditions, ATP application resulted in a membrane hyperpolarization of approximately 35 mV. The IK(Ca) current downregulated during myogenesis, ceasing to be detectable 4 days after the myoblasts were placed in differentiating medium. Downregulation was prevented by the myogenic suppressor agent basic FGF (bFGF). We also found that block of the IK(Ca) channel by charybdotoxin did not inhibit bFGF-sustained myoblast proliferation. These observations show that in C2C12 myoblasts the IK(Ca) channel expression correlates inversely with differentiation, yet it does not appear to have a role in myoblast proliferation.

De novo generation of cationic antimicrobial peptides: influence of length and tryptophan substitution on antimicrobial activity

Comparison of human immunodeficiency virus lentiviral lytic peptide 1 with other host-derived peptides indicates that antimicrobial properties of membrane-active peptides are markedly influenced by their cationic, hydrophobic, and amphipathic properties. Many common themes, such as Arg composition of the cationic face of an amphipathic helix and the importance of maintaining the hydrophobic face, have been deduced from these observations. These studies suggest that a peptide with these structural properties can be derived de novo by using only a few strategically positioned amino acids. However, the effects of length and helicity on antimicrobial activity and selectivity have not been objectively evaluated in the context of this motif. To address these structure-function issues, multimers of a 12-residue lytic base unit (LBU) peptide composed only of Arg and Val residues aligned to form idealized amphipathic helices were designed. Bacterial killing assays and circular dichroism analyses reveal a strong correlation between antibacterial activity, peptide length, and propensity to form a helix in solvent mimicking the environment of a membrane. Increasing peptide length beyond two LBUs (24-residue peptides) resulted in no appreciable increase in antimicrobial activity. Derivatives (WLBU) of the LBU series were further engineered by substituting Trp residues in the hydrophobic domains. The 24-residue WLBU2 peptide was active at physiologic NaCl concentrations against Staphylococcus aureus and mucoid and nonmucoid strains of Pseudomonas aeruginosa. Further, WLBU2 displayed the highest antibacterial selectivity of all peptides evaluated in the present study by using a coculture model of P. aeruginosa and primary human skin fibroblasts. These findings provide fundamental information toward the de novo design of an antimicrobial peptide useful for the management of infectious diseases.

Effect of treatment with free and liposomized albendazole on selected immunological parameters and cyst growth in mice infected with Echinococcus multilocularis

Selected immunological parameters in healthy mice and mice infected with Echinococcus multilocularis and the effect of free and liposomized albendazole (lip.ABZ) upon these parameters in relation to the reduction of parasite growth were investigated over 26 weeks. Proliferative response of splenic T and B lymphocytes, number of CD4+ and CD8+ spleen T cell subpopulations, serum concentration of IFN-gamma and IL-5, and generation of superoxide anion (O2-) by peritoneal macrophages were the chosen parameters. Both drug forms were given to mice at a dose of 10 mg kg(-1) twice a week from week 4 to week 10 post infection (p.i.) (6 weeks in total). The reduction of cyst growth after treatment with ABZ and lip.ABZ was similar up to week 4 after last dose, but the parasitostatic effect of lip.ABZ lasted 4 weeks longer than the effect of free drug. After administration of both drug forms, the proliferative responses of T and B cells were restored, and also the number of CD4+ and CD8+ increased markedly. In lip.ABZ-treated mice, stimulation of mentioned lymphocyte parameters, except that of CD8+ numbers, persisted for longer period than after ABZ therapy, where values peaked at week 12 p.i., then declined more rapidly. A very strong stimulatory effect was seen on B lymphocytes during the period of lip.ABZ administration, although interestingly, numbers of CD8+ cells were higher in free ABZ-treated group. Low concentrations of IFN-gamma (Th1 response) were present in infected, untreated mouse serum. Only moderate IFN-gamma elevation was observed after treatment with free ABZ. A profound increase of its concentration was seen shortly after administration of lip.ABZ, and persisted until the experiment ended. In infected untreated mice, concentration of IL-5 (Th2 response) was highest on week 2 p.i. Significantly more IL-5 was recorded in serum of mice treated with free ABZ treatment than with lip.ABZ from week 12 to 18 p.i. (weeks 2-8 after the last dose). After the initial increase of superoxide anions (weeks 4-11 p.i.), generation of O2- by peritoneal macrophages was gradually inhibited by E. multilcoularis infection. In general, treatment abolished this suppression and macrophages from lip.ABZ-treated mice produced elevated amounts of O2- over a longer period than macrophages from ABZ-treated mice. Our data indicate that anthelmintic potency of ABZ could be increased after incorporation into liposomes, not only because of improved pharmacokinetics and consequent bioavailability, but also because of significant stimulation of Th1-type cytokine IFN-gamma response and effector macrophage functions.

Antioxidant effect of Inonotus obliquus

The mushroom Inonotus obliquus (Fr.) Pilát (Hymenochaetaceae), has been widely used as a folk medicine in Russia, Poland and most of the Baltic countries. The purpose of this study was to elucidate the antioxidant capacities of Inonotus obliquus. Four extracts from the fungus were evaluated for antioxidant activity against the 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, and peroxyl radicals. The polyphenolic extract had a strong antioxidant activity, and the extract containing triterpenoids and steroids presented a relatively strong antioxidant effect. The polysaccharide extract, however, was inactive. The protective effects of these four extracts were assessed against hydrogen peroxide-induced oxidative stress using a human keratinocyte cell line, HaCaT. Our results show that the polyphenolic extract protected these cells against hydrogen peroxide-induced oxidative stress, while the polysaccharide, triterpenoid and steroid extracts were ineffective. Additionally, the remnant polyphenolic and low molecular weight polysaccharide extracts showed a weakly protective effect at a concentration of 50 microg/ml. Our results indicate that Inonotus obliquus has the capacity to scavenge free radicals at concentrations higher than 5 microg/ml and that the polyphenolic extract can protect cells against oxidative stress.

Immune response in mice infected by Encephalitozoon cuniculi and suppressed by dexamethasone

Several indicators of immune response were observed in immunocompetent mice of the ICR line and those suppressed by dexamethasone upon their experimental infection with the microsporidia of Encephalitozoon cuniculi. The mice were infected by one-shot intraperitoneal administration of 5 x 10(7) pathogenic spores. On Days 7, 14, 28 and 42 after infection, peripheral blood leukocyte phagocytic activity was determined and compared, including phagocytic index and the blastogenic response in spleen cells to mitogenic activation by concanavalin A and phytohaemagglutinin. The results point to the fact that E. cuniculi itself can cause a significant decrease in phagocytic activity of phagocytic leukocytes in the early stages of infection as well as a remarkable decrease in the proliferative response of spleen cells to T-cellular mitogens.

The MTT assays of bovine retinal pericytes and human microvascular endothelial cells on DLC and Si-DLC-coated TCPS

MTT (Tetrazolium)-assay suggests that diamond-like carbon (DLC) and silicon-doped DLC (Si-DLC) films obtained under appropriate deposition parameters are not toxic to bovine retinal pericytes, and human microvascular endothelial cells (HMEC). The observed frequency distributions of the optical density (OD) values indicative of cell viability are near Gaussian-normal distribution. One-way ANOVA indicates that at 0.05 levels the population means are not significantly different for the coated and control samples. The observed OD values depend on the cell line (cell growth/metabolic rate), possibly cell cycle stage, the deposition parameters-bias voltage, ion energy, pressure, argon precleaning, and the dopant. For colored thin films like DLC with room temperature photoconductivity and photoelectric effects, it is important to account for the OD contribution from the coating itself. MTT assay, not surprisingly, seems not to be highly sensitive to interfacial cellular interaction resulting from the change in the film's nanostructure, because the tetrazolium metabolism is mainly intracellular and not interfacial. The thin films were synthesized by 13.56 MHz RF-PECVD using argon and acetylene as source gases, with tetramethylsilane (TMS) vapor introduced for silicon doping. This study could be relevant to biomedical application of the films in the eye, peri-vascular, vascular compartments, and for cell-tissue engineering.

S100B causes apoptosis in a myoblast cell line in a RAGE-independent manner

S100B, a Ca(2+)-modulated protein with both intracellular and extracellular regulatory roles, is most abundant in astrocytes, is expressed in various amounts in several non-nervous cells and is also found in normal serum. Astrocytes secrete S100B, and extracellular S100B exerts trophic and toxic effects on neurons depending on its concentration, in part by interacting with the receptor for advanced glycation end products (RAGE). The presence of S100B in normal serum and elevation of its serum concentration in several non-nervous pathological conditions suggest that S100B-expressing cells outside the brain might release the protein and S100B might affect non-nervous cells. Recently we reported that at picomolar to nanomolar doses S100B inhibits rat L6 myoblast differentiation via inactivation of p38 kinase in a RAGE-independent manner. We show here that at >or=5 nM in the absence of and at >100 nM in the presence of serum S100B causes myoblast apoptosis via stimulation of reactive oxygen species (ROS) production and inhibition of the pro-survival kinase, extracellular signal-regulated kinase (ERK)1/2, again in a RAGE-independent manner. Together with our previous data, the present results suggest that S100B might participate in the regulation of muscle development and regeneration by two independent mechanism, i.e., by inhibiting crucial steps of the myogenic program at the physiological levels found in serum and by causing elevation of ROS production and myoblast apoptosis following accumulation in serum and/or muscle extracellular space. Our data also suggest that RAGE has no role in the transduction of S100B effects on myoblasts, implying that S100B can interact with more than one receptor to affect its target cells.

Effects of the mycotoxin ochratoxin A and some of its metabolites on human kidney cell lines

The modulations of complement-regulating surface proteins on a human embryonic and a renal carcinoma cell line are described regarding the effects of ochratoxin A and some of its metabolites on the surface markers CD46, CD55 and CD59. Membrane integrity, cell proliferation and metabolic activity were reduced to different extents, depending on the kind of mycotoxin and the dosage, which was ranging from 10 to 1000 ng/ml. The number of cells carrying surface markers was suppressed significantly at 1000 ng/ml, in some cases even at 100 ng/ml, whereas the intensity of receptor expression on the positive cells was found to be stimulated. The fraction RE2 (OTC) isolated from an OTA-containing crude toxin surpassed the effects of all other ochratoxin metabolites. Apart from well-known cytotoxic and genotoxic effects modulation of cell surface marker expression by low concentrations of OTA and OTC deserves more attention with regard to its immuno-pathogenic importance. Furthermore, occurrence and impact of the mycotoxin OTC should be studied more into detail.

Effects of the mycotoxin ochratoxin A and some of its metabolites on the human cell line THP-1

The immunomodulatory effects of ochratoxin A (OTA) and some of its metabolites on the human monocyte/macrophage line THP-1 are described. Metabolic activity, cell proliferation, cell membrane integrity, cell differentiation, phagocytic behaviour, nitrogen oxide synthesis and cell surface markers were largely suppressed by these mycotoxins at concentrations between 10 and 1000 ng/ml, in individual cases already at 1 ng/ml. After analysis of a crude toxin, a substance designated RE2 could be isolated besides OTA, which was identified as ochratoxin C (OTC). The latter showed a stronger suppressive effect on most functions studied than all other metabolites of OTA. Because of the immunomodulatory effects of OTA and OTC, more attention should be paid to their immunopathogenic importance in addition to their known cytotoxic and genotoxic effects. The occurrence and importance of the mycotoxin OTC should be more closely examined in this context.

N-CAM expression and localization in PC12 cells modulated by extracellular peptides

The neural cell adhesion molecules (N-CAMs) play an important role in mediating cell-cell interactions in the nervous system. Different isoforms of these membrane proteins are involved in the formation of the neuronal network and in the dynamic phases of neuronal plasticity. We studied the early stages of the pseudo neuronal differentiation of PC12 cells induced by a class of small acidic peptides capable of modulating gene expression in these cells. The data presented here indicate that peptides with specific sequences induce an increase in N-CAM mRNA expression and protein translocation to the plasma membrane to a comparable degree as NGF.

p38 MAP kinase mediates the cell death induced by PrP106-126 in the SH-SY5Y neuroblastoma cells

Prion diseases are neurodegenerative pathologies characterized by the accumulation in the brain of a protease-resistant form of the prion protein (PrP(c)), named PrP(Sc). A synthetic peptide homologous to residues 106-126 of PrP (PrP106-126) maintains many PrP(Sc) characteristics. We investigated the intracellular signaling responsible for the PrP106-126-dependent cell death of SH-SY5Y, a cell line derived from a human neuroblastoma. In this cell line, PrP106-126 induced apoptotic cell death and caused activation of caspase-3, although the blockade of this enzyme did not inhibit cell death. The p38 MAP kinase blockers, SB203580 and PD169316, prevented the apoptotic cell death evoked by PrP106-126 and Western blot analysis revealed that the exposure of the cells to the peptide induced p38 phosphorylation. Taken together, our data suggest that the p38 MAP kinase pathway can mediate the SH-SY5Y cell death induced by PrP106-126.

gamma-Glutamyltranspeptidase-dependent metabolism of 4-hydroxynonenal-glutathione conjugate

A major pathway for detoxification of the highly reactive lipid peroxidation product, 4-hydroxy-2,3-trans-nonenal (HNE) is through the conjugation with glutathione (GSH). We have studied the metabolism of GS-HNE conjugate by the enzyme gamma-glutamyltranspeptidase (GGT) using its purified form, as well as a GGT-overexpressing fibroblast cell line (V79 GGT). Using mass spectrometry analysis we identified for the first time cysteinylglycine-HNE (CysGly-HNE) as the GGT metabolite of GS-HNE. Furthermore, the GGT-dependent metabolism of GS-HNE in the V79 GGT cell line was associated with a considerable increase of cytotoxicity as compared to a control cell line which does not express GGT (V79 Cl). The cytotoxic effect was dose- and time-dependent (100% cellular death at 200 microM GS-HNE after 24 h incubation) in V79 GGT cells, whereas no decrease of viability was observed in V79 Cl cells. A similar cytotoxic effect was obtained when cells were incubated directly with CysGly-HNE, demonstrating that this GGT-dependent metabolite unlike GS-HNE, exhibits cytotoxic properties.

Synthesis and characterization of tetramethylrhodaminethiocarbamoyl-(Glu(1))-epidermal mitosis-inhibiting pentapeptide

A fluorescent analog of epidermal mitosis-inhibiting pentapeptide (pGlu-Glu-Asp-Ser-Gly) was synthesized by reacting tetramethylrhodamine isothiocyanate with ring-opened epidermal mitosis-inhibiting pentapeptide. The ring-opening reaction of the pyrrolidone moiety was performed with mild acidic hydrolysis and the product purified by reversed-phase high-performance liquid chromatography. Tetramethylrhodaminethiocarbamoyl-(Glu(1))-epidermal mitosis-inhibiting pentapeptide was purified by chromatography on Sephadex G-25 and reversed-phase high-performance liquid chromatography. After characterization by amino acid analysis, the analog was incubated in presence of A431 cell line to visualize the cellular localization of the epidermal mitosis-inhibiting pentapeptide. The data gave negative results.

Mechanisms of taxotere-related drug resistance in pancreatic carcinoma

BACKGROUND

Pancreatic adenocarcinoma (PAC) is generally refractory to most chemotherapeutic agents, including docetaxel (Taxotere; TXT). Specific mechanisms for TXT-related drug resistance in PAC have not been defined. The hypothesis of this study was that PAC resistance to TXT is primarily related to P-glycoprotein (P-gp), the expression product of multiple drug resistance (MDR)-1, as opposed to lung resistance protein (LRP) or multidrug resistance protein (MRP).

MATERIALS AND METHODS

The sensitivity of the PAC cell line SUIT-2 and its sublines to TXT, doxorubicin (DOX) and 5-fluorouracil (5-FU) was evaluated with a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. MDR1 (P-gp), MRP, LRP, and beta-tubulin isotype gene expressions were detected at the messenger RNA level by reverse transcription-polymerase chain reaction (RT-PCR). Verapamil and indomethacin (IMC) were used to test the functionality of P-gp and MRP, respectively.

RESULTS

The SUIT-2 subline S-020 and the TXT-selected SUIT-2 cell line S2/TXT were significantly resistant to TXT. Both showed cross-resistance to DOX but no resistance to 5-FU. RT-PCR demonstrated strong expression of P-gp in S-020 and S2/TXT and weaker or no expression in other cells lines. MRP and LRP expression was found in most of these cell lines but had no relationship to the TXT resistance. TXT resistance in S2-020 and S2/TXT could be reversed by verapamil but not by IMC. Levels of beta-tubulin isotype II and III were increased in S2/TXT compared with S-020 and SUIT-2.

CONCLUSIONS

Intrinsic and acquired TXT resistance is primarily mediated by P-gp, but not by MRP or LRP, and is markedly reversed by the P-gp modulator verapamil. Hence future related studies should focus on the use of agents that block the transporter action of P-gp.

New structural analogues of Tubulozole induce apoptosis, [Ca2+]i modifications and cytoskeletal disorganization in glial (GL15) and neuronal-like (PC12) cell lines

The synthesis and the biological activity of (+/-)-cis- and (+/-)-trans-[4-[[2-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-ylmethyl)-1, 3-dioxolan-4-yl]methylthio]phenyl]carbamic acid ethyl esters (2a and 2b) are discussed. They were designed as structural analogues of Tubulozole, a synthetic tubulin polymerisation inhibitor with antimitotic properties. Biological tests were carried out on PC12, a neuronal-like cell line derived from rat pheochromocytoma, and on GL15, a cell line derived from human glioblastoma. The exposure (from 5 to 20 h) of GL15 and PC12 cells to different concentrations (0.1-1000 microM; IC50 approximately 1 microM) of 2a or 2b resulted in a drastic decrease in the number of viable cells without an apparent effect on the cell distribution in the various phases of the cell cycle. Compound 2a or 2b (10 microM) induced cell death by activating apoptosis. This was correlated with the activation of an oscillating Ca(2+)-dependent mechanism which increased the intracellular calcium concentration ([Ca2+]i) via Ca(2+)-release from internal stores. Moreover, 2a (10 microM) also induced severe damage of cytoskeletal F-actin filaments after a 5 h incubation in GL15 cells. This was also observed but to a smaller extent, for 2b. Under the same experimental conditions, PC12 cells showed similar actin deregulation.

Unusual N-glycosylation of a recombinant human erythropoietin expressed in a human lymphoblastoid cell line does not alter its biological properties

Erythropoietin (Epo) is a 166 amino acids protein containing three N-glycosylation sites (Asn-24, Asn-38, and Asn-83) and 1 O- glycosylation site (Ser-126) and involved in the regulation of the level of red blood cells. Today, only one recombinant human Epo (rHuEpo), produced in CHO cell line, is extensively used in therapy to cure severe anemia. The structure of the glycan chains of this rHuEpo slightly differ of those of the urinary human Epo (uHuEpo), considered as the natural Epo molecule. In an attempt to produce a rHuEpo as close as possible to the uHuEpo, Epo gene was expressed in a human lymphoblastoid cell line, named RPMI 1788. In order to fully characterize the Epo-RPMI, structural characterizations of the protein skeleton as well as glycan chains were undergone. As expected, the amino acid sequence of the Epo-RPMI conformed to that of uHuEpo. Surprisingly, the structure of some N-glycan chains, as mainly determined by ESI-MS, revealed some unusual characteristics. Thus, 80% of N-glycans possess a bisecting GlcNAc residue, 25% bear a second fucose residue which is present, in a large part, in a sialyl Le(x)motif, and 13% contain more than three LacNAc repeats (up to five per molecule). Despite these unusual structural characteristics, the data concerning the in vitro and in vivo biological activities were not impaired when compared to Epo-CHO and uHuEpo.

Increased T cell cytotoxicity by Betathine-induced upregulation of TNFalpha

Betathine (BT) is a low molecular weight disulfide that has previously been shown to exhibit in vivo antitumor activity in murine myeloma and melanoma models. We have shown that BT treatment of both human T cells and monocytes is associated with an increase in surface tumor necrosis alpha (TNFalpha) expression. Further, in T cells and monocytes that have been stimulated with PMA and ionomycin, the addition of BT results in a dose and time dependent increase in the percentage of high TNFalpha-expressing cells. Unlike TNFalpha upregulation produced by the commonly used thiol antioxidant N-acetyl-L-cysteine (NAC), the BT-induced increase in TNFalpha is observed consistently in different donors. This increase in surface TNFalpha is associated with elevated levels of TNFalpha mRNA. In addition, expression of TNFalpha receptor I is also significantly enhanced by BT treatment. The upregulation of surface TNFalpha by BT has functional consequences, in that, BT-treated T cells exhibit enhanced cytotoxic activity. Thus, increased TNFalpha expression may be one mechanism responsible for the antineoplastic activity of BT.