A novel one-step, highly sensitive fluorometric assay to evaluate cell-mediated cytotoxicity

Heat treatment of Na2O-CaO-P2O5-SiO2 bioactive glasses: densification processes and postsintering bioactivity

Because of their excellent bioactivity, bioactive glasses are increasingly diffused to produce biomedical devices for bone prostheses, to face the dysfunctions that may be caused by traumatic events, diseases, or even natural aging. However, several processing routes, such as the production of scaffolds or the deposition of coatings, include a thermal treatment to apply or sinter the glass. The exposure to high temperature may induce a devetrification phenomenon, altering the properties and, in particular, the bioactivity of the glass. The present contribution offers an overview of the thermal behavior and properties of two glasses belonging to the Na2O-CaO-P2O5-SiO2 system, to be compared to the standard 45S5 Bioglass(®). The basic goal is to understand the effect of both the original composition and the thermal treatment on the performance of the sintered glasses. The new glasses, the one (BG_Na) with a high content of Na2O, the other (BG_Ca) with a high content of CaO, were fully characterized and sintering tests were performed to define the most interesting firing cycles. The sintered samples, treated at 880°C and 800°C respectively, were investigated from a microstructural point of view and their mechanical properties were compared to those of the bulk (not sintered) glass counterparts. The effect of sintering was especially striking on the BG_Ca material, whose Vickers hardness increased from 598.9 ± 46.7 HV to 1053.4 ± 35.0 HV. The in vitro tests confirmed the ability of the glasses, both in bulk and sintered form, of generating a hydroxyapatite surface layer when immersed in a simulated body fluid. More accurate biological tests performed on the sintered glasses proved the high bioactivity of the CaO-rich composition even after a heat treatment.

Vaccination of lactating dairy cows for the prevention of aflatoxin B1 carry over in milk

The potential of anaflatoxin B₁ (AnAFB₁) conjugated to keyhole limpet hemocyanin (KLH) as a vaccine (AnAFB₁-KLH) in controlling the carry over of the aflatoxin B₁ (AFB₁) metabolite aflatoxin M₁ (AFM₁) in cow milk is reported. AFB₁ is the most carcinogenic compound in food and foodstuffs amongst aflatoxins (AFs). AnAFB₁ is AFB₁ chemically modified as AFB₁-1(O-carboxymethyl) oxime. In comparison to AFB₁, AnAFB₁ has proven to be non-toxic in vitro to human hepatocarcinoma cells and non mutagenic to Salmonella typhimurium strains. AnAFB₁-KLH was used for immunization of cows proving to induce a long lasting titer of anti-AFB₁ IgG antibodies (Abs) which were cross reactive with AFB₁, AFG₁, and AFG₂. The elicited anti-AFB₁ Abs were able to hinder the secretion of AFM₁ into the milk of cows continuously fed with AFB₁. Vaccination of lactating animals with conjugated AnAFB₁ may represent a solution to the public hazard constituted by milk and cheese contaminated with AFs.

HAT4, a Golgi apparatus-anchored B-type histone acetyltransferase, acetylates free histone H4 and facilitates chromatin assembly

Histone acetyltransferases (HATs) are an essential regulatory component in chromatin biology. Unlike A-type HATs, which are found in the nucleus and utilize nucleosomal histones as substrates and thus primarily function in transcriptional regulation, B-type HATs have been characterized as cytoplasmic enzymes that catalyze the acetylation of free histones. Here, we report on a member of the GCN5-related N-acetyltransferase superfamily and another B-type HAT, HAT4. Interestingly, HAT4 is localized in the Golgi apparatus and displays a substrate preference for lysine residues of free histone H4, including H4K79 and H4K91, that reside in the globular domain of H4. Significantly, HAT4 depletion impaired nucleosome assembly, inhibited cell proliferation, sensitized cells to DNA damage, and induced cell apoptosis. Our data indicate that HAT4 is an important player in the organization and function of the genome and may contribute to the diversity and complexity of higher eukaryotic organisms.

Modulatory profiling identifies mechanisms of small molecule-induced cell death

Cell death is a complex process that plays a vital role in development, homeostasis, and disease. Our understanding of and ability to control cell death is impeded by an incomplete characterization of the full range of cell death processes that occur in mammalian systems, especially in response to exogenous perturbations. We present here a general approach to address this problem, which we call modulatory profiling. Modulatory profiles are composed of the changes in potency and efficacy of lethal compounds produced by a second cell death-modulating agent in human cell lines. We show that compounds with the same characterized mechanism of action have similar modulatory profiles. Furthermore, clustering of modulatory profiles revealed relationships not evident when clustering lethal compounds based on gene expression profiles alone. Finally, modulatory profiling of compounds correctly predicted three previously uncharacterized compounds to be microtubule-destabilizing agents, classified numerous compounds that act nonspecifically, and identified compounds that cause cell death through a mechanism that is morphologically and biochemically distinct from previously established ones.

Inhibition of enterovirus 71 replication by chrysosplenetin and penduletin

In recent years, enterovirus 71 (EV71) infections have caused an increasing epidemic in young children, accompanying with more severe nervous system disease and more deaths. Unfortunately, there is no specific medication for it so far. Here we investigated the anti-EV71 activity of chrysosplenetin and penduletin, two o-methylated flavonols isolated from the leaves of Laggera pterodonta. These two compounds were found to have strong activity in vitro against EV71 with low cytotoxicity. In the cytopathic effect (CPE) inhibition assays, both plaque reduction assay and virus yield inhibition assay, the compounds showed a similar 50% inhibitory concentration (IC(50)) value of about 0.20 μM. The selectivity indices (SI) of chrysosplenetin and penduletin were 107.5 and 655.6 in African green monkey kidney (Vero) cells, and 69.5 and 200.5 in human rhabdomyosarcoma (RD) cells, accordingly. The preliminary mechanism analysis indicates that they function not through blocking virus entry or inactivating virus directly but inhibiting viral RNA replication. In the time-of-addition assay, both compounds inhibited progeny virus production and RNA replication by nearly 100% when introduced within 4h post infection. In addition to EV71, both compounds inhibited several other human enteroviruses with similar efficacy. These findings provide a significant lead for the discovery of anti-EV71 drug.

Ral GTPases regulate cell-mediated cytotoxicity in NK cells

NK cells are key components of the immune response to virally infected and tumor cells. Recognition of target cells initiates a series of events in NK cells that culminates in target destruction via directed secretion of lytic granules. Ral proteins are members of the Ras superfamily of small GTPases; they regulate vesicular trafficking and polarized granule secretion in several cell types. In this study, we address the role of Ral GTPases in cell-mediated cytotoxicity. Using a human NK cell line and human primary NK cells, we show that both Ral isoforms, RalA and RalB, are activated rapidly after target cell recognition. Furthermore, silencing of RalA and RalB impaired NK cell cytotoxicity. RalA regulated granule polarization toward the immunological synapse and the subsequent process of degranulation, whereas RalB regulated degranulation but not polarization of lytic granules. Analysis of the molecular mechanism indicated that Ral activation in NK cells leads to assembly of the exocyst, a protein complex involved in polarized secretion. This assembly is required for degranulation, as interference with expression of the exocyst component Sec5 led to reduced degranulation and impaired cytotoxicity in NK cells. Our results thus identify a role for Ral in cell-mediated cytotoxicity, implicating these GTPases in lymphocyte function.

Sudemycins, novel small molecule analogues of FR901464, induce alternative gene splicing

Two unrelated bacterial natural products, FR901464 and pladienolide B, have previously been shown to have significant antitumor activity in vivo. These compounds target the SF3b subunit of the spliceosome, with a derivative of pladienolide (E7107) entering clinical trials for cancer. However, due to the structural complexity of these molecules, their research and development has been significantly constrained. We have generated a set of novel analogues (Sudemycins) that possess the pharmacophore that is common to FR901464 and pladienolide, via a flexible enantioselective route, which allows for the production of gram quantities of drug. These compounds demonstrate cytotoxicity toward human tumor cell lines in culture and exhibit antitumor activity in a xenograft model. Here, we present evidence that Sudemycins are potent modulators of alternative splicing in human cells, both of endogenous genes and from minigene constructs. Furthermore, levels of alternative splicing are increased in tumor cells relative to normal cells, and these modifications can be observed in human tumor xenografts in vivo following exposure of animals to the drug. In addition, the change in the splicing pattern observed with the Sudemycins are similar to that observed with Spliceostatin A, a molecule known to interact with the SF3b subunit of the spliceosome. Hence, we conclude that Sudemycins can regulate the production of alternatively spliced RNA transcripts and these alterations are more prevalent in tumors, as compared to normal cells, following drug exposure. These studies suggest that modulation of alternative splicing may play a role in the antitumor activity of this class of agents.

Toxicity profiles of four metals and 17 xenobiotics in the human hepatoma cell line HepG2 and the protozoa Tetrahymena pyriformis--a comparison

We performed an interspecies comparison for the human hepatoma cell line HepG2 and the eukaryotic single cell organism Tetrahymena pyriformis (T. pyriformis) for 17 xenobiotics with diverse structures and four metals. The cytotoxicity was assessed by four different cell viability assays (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide reduction (MTT), neutral red uptake (NRU), resazurin dye (AlamarBlue), 5-carboxyfluorescein diacetate acetoxymethyl ester (CFDA-AM)) for the HepG2 and by cell count and MTT for T. pyriformis. For HepG2 cells, the results revealed interassay variations depending on the compound. The highest assay conformity was found for the metal Hg(2+) and the fungicide prochloraz. The AlamarBlue assay was the most sensitive assay according to low-effect concentrations. By contrast, the NRU assay was comprised of more frequent whole concentration response relationships and was more susceptible to EC(50). For T. pyriformis the EC(50) values of the two applied assays displayed a high conformity (R(2) = 0.97). Comparing the EC(50) values obtained by the MTT assay for the two cell models, a direct correlation was absent for the xenobiotics and only present for the metals (Cd(2+), Cu(2+), and Ni(2+)). Moreover, the protozoa T. pyriformis displayed a 20 times higher sensitivity than the cell line. The highest interspecies difference of three log degrees was obtained for the polycyclic aromatic hydrocarbon fluoranthene. In addition, a correlation of the EC(50) values and octanol-water partition coefficient (log K(OW)) of the xenobiotics was performed. No correlation was found for HepG2, and a weak one for T. pyriformis. Interestingly, the interspecies difference of logarithmized EC(50) correlated positive with the log K(OW) (R(2) = 0.65). In conclusion, to obtain reliable evidence for human cytotoxicity, more than one viability/cytotoxicity assay had to be applied for cell lines. Second, the human hepatoma cell line was less affected by the organic compounds than the eukaryotic single-cell organism and was also less dependent on the log K(OW) of the xenobiotic.

Resazurin dye as a reliable tool for determination of cell number and viability in mesenchymal stem cell culture

Human mesenchymal stem cells are a valuable cell source for tissue engineering. Determination of cell number and viability is crucial. However, this can be tested only at the end of cell culture. This study shows that Resazurin dye staining is a reliable tool for evaluation of cell number and viability in culture without cell perturbation.

Comparative cytotoxicity evaluation of lanthanide nanomaterials on mouse and human cell lines with metabolic and DNA-quantification assays

Lanthanide nanomaterials are considered a less toxic alternative to quantum dots for bioimaging applications. This study evaluated the cytotoxicity of terbium (Tb)-doped gadolinium oxide (Gd(2)O(3)) and dysprosium oxide (Dy(2)O(3)) nanoparticles exposed to human (BEAS-2B) and mouse (L929) cell lines at a concentration range of 200-2000 μg/ml for 48 h. Two assay methods were utilized-WST-8 assay (colorimetric) based on mitochondrial metabolic activity and Pico-Green assay (fluorescence), which measures total DNA content. The authors' data showed that Tb-doped Gd(2)O(3) nanoparticles were consistently more toxic than Tb-doped Dy(2)O(3) nanoparticles. However, exposure to these nanomaterials caused a decrease in proliferation rate for both cell lines rather than a net loss of viable cells after 48 h of exposure. Additionally, there was some degree of discrepancy observed with the two assay methods. For the mouse L929 cell line, the WST-8 assay yielded consistently lower proliferation rates compared to the Pico-Green assay, whereas the opposite trend was observed for the human BEAS-2B cell line. This could arise because of the differential effects of these nanoparticles on the metabolism of L929 and BEAS-2B cells, which in turn may translate to differences in their postexposure proliferation rates. Hence, the Pico-Green assay could have an advantage over the WST-8 assay because it is not skewed by the differential effects of nanomaterials on cellular metabolism.

A Rapid Colorimetric Microtiter Bioassay to Evaluate Fungicide Sensitivity Among Verticillium dahliae Isolates

Management of Verticillium wilt relies on the adoption of integrated control strategies. The effects of long-term chemical use may be negated by the development of fungicide resistance. A rapid colorimetric bioassay was developed to evaluate sensitivity of V. dahliae isolates to differently acting fungicides. This assay capitalizes on the advantages of a 96-well microtiter plate format and the nontoxic cell viability dye, Alamar Blue (AB). Analysis of variance revealed that incubation time, spore density, and media type were important parameters that must be optimized for the AB assay. The effective linear range of the assay was dependent on incubation time and spore density. Survival of 10⁷ spores/ml of each of 10 isolates in the presence of a range of serial dilutions of nine commercial fungicides was assessed. Effective concentrations at 50 and 90% inhibition of growth were calculated for each fungicide. A comparison of the percent growth inhibition for each fungicide at 0.6 mg/ml, as determined by AB and amended-agar assays, revealed a strong positive correlation for six of the fungicides. The optimized AB assay proved to be a rapid and reproducible method of testing the efficacy of fungicides with the option of deriving quantitative or qualitative data.

Three-dimensional laser micro- and nano-structuring of acrylated poly(ethylene glycol) materials and evaluation of their cytoxicity for tissue engineering applications

The natural cell environment is characterized by complex three-dimensional structures, which contain features at multiple length scales. Many in vitro studies of cell behavior in three dimensions rely on the availability of artificial scaffolds with controlled three-dimensional topologies. In this paper, we demonstrate fabrication of three-dimensional scaffolds for tissue engineering out of poly(ethylene glycol) diacrylate (PEGda) materials by means of two-photon polymerization (2PP). This laser nanostructuring approach offers unique possibilities for rapid manufacturing of three-dimensional structures with arbitrary geometries. The spatial resolution dependence on the applied irradiation parameters is investigated for two PEGda formulations, which are characterized by molecular weights of 302 and 742. We demonstrate that minimum feature sizes of 200nm are obtained in both materials. In addition, an extensive study of the cytotoxicity of the material formulations with respect to photoinitiator type and photoinitiator concentration is undertaken. Aqueous extracts from photopolymerized PEGda samples indicate the presence of water-soluble molecules, which are toxic to fibroblasts. It is shown that sample aging in aqueous medium reduces the cytotoxicity of these extracts; this mechanism provides a route for biomedical applications of structures generated by 2PP microfabrication and photopolymerization technologies in general. Finally, a fully biocompatible combination of PEGda and a photoinitiator is identified. Fabrication of reproducible scaffold structures is very important for systematic investigation of cellular processes in three dimensions and for better understanding of in vitro tissue formation. The results of this work suggest that 2PP may be used to polymerize poly(ethylene glycol)-based materials into three-dimensional structures with well-defined geometries that mimic the physical and biological properties of native cell environments.

Bioactive polymeric systems with platelet antiaggregating activity for the coating of vascular devices

The preparation, characterization, and analysis of physicochemical and biological properties of a new bioactive polymer system, based on a copolymer of an acrylic derivative of triflusal (a molecule with chemical structure related to aspirin with antiaggregating activity for platelets) is described and evaluated as thin bioactive coating for vascular grafts and coronary stents. The acrylic monomer derived from triflusal (THEMA) provides random copolymers when it is polymerized with butyl acrylate (BA), according to their reactivity ratios, r(THEMA) = 1.05 and r(BA) = 0.33. The copolymer THBA70, containing a molar composition f(THEMA) = 0.45 and f(BA) = 0.55 presents the optimal properties of stability, flexibility, and adhesion, with a T(g) = 21 ± 2 °C, to be applied as bioactive and biostable coatings for vascular grafts and coronary stents. Thin films of this copolymer system present an excellent biocompatibility and a good inherent antiaggregant activity for platelets.

Akt, 14-3-3ζ, and vimentin mediate a drug-resistant invasive phenotype in diffuse large B-cell lymphoma

Development of resistance to the CHOP chemotherapeutic regimen (cyclophosphamide, doxorubicin, vincristine, prednisone) remains a major cause of treatment failure and mortality in approximately 40% of patients with diffuse large B-cell lymphoma (DLBCL). We established CHOP-resistant DLBCL cells as a model system to investigate molecular mechanisms involved in multidrug resistance. Two-dimensional differential in-gel (DIGE) analysis identified 10 differentially expressed proteins between CHOP-sensitive and -resistant DLBCL cells that play roles in glycolysis (triosephosphate isomerase-1, enolase-1), cytoskeletal structure (ezrin, vimentin, tubulin-specific chaperone B), purine biosynthesis (serine hydroxymethyltransferase), calcium binding (sorcin), and apoptosis (p53, 14-3-3ζ, Akt). Akt, 14-3-3ζ, and vimentin were up-regulated in CHOP-resistant DLBCL cells. We showed previously that siRNA-mediated knockdown of 14-3-3ζ reversed CHOP resistance in DLBCL cells (Maxwell et al., J Biol Chem 2009;284:22379-22389). Here we show that chemical inhibition of Akt overcomes CHOP resistance in DLBCL cells. CHOP-resistant cells exhibited a five-fold greater ability to invade collagen matrices compared with CHOP-sensitive cells. Knockdown of vimentin by siRNA or withaferin A repressed the invasiveness of CHOP-resistant cells in collagen matrices. Increased expressions of Akt, 14-3-3ζ, and vimentin were observed by Western blotting in primary DLBCL tissues relative to normal lymphatic tissue. The data implicate activation of an Akt-14-3-3ζ signaling pathway in promoting a multidrug-resistant phenotype associated with a vimentin-dependent invasive behavior in DLBCL cells.

The human NKG2D ligand ULBP2 can be expressed at the cell surface with or without a GPI anchor and both forms can activate NK cells

The activating immune receptor NKG2D binds to several stress-induced ligands that are structurally different. MHC-class-I-related chain (MIC) A/B molecules have a transmembrane domain, whereas most UL16 binding proteins (ULBPs) are glycosylphosphatidylinositol (GPI)-linked molecules. The significance of this variability in membrane anchors is unclear. Here, we demonstrate that ULBP2, but not ULBP1 or ULBP3, can reach the cell surface without the GPI modification. Several proteins are expressed at the cell surface as both transmembrane and GPI-linked molecules, either via alternative splicing or by the expression of linked genes. However, to our knowledge, ULBP2 is the first single mammalian cDNA that can be expressed as either a transmembrane or a GPI-anchored protein. The rate of maturation and the levels of cell surface expression of the non-GPI-linked form were lower than those of the GPI-linked ULBP2. Nonetheless, non-GPI ULBP2 was recognised by NKG2D and triggered NK cell cytotoxicity. These data show that differences in membrane attachment by NKG2D ligands are more important for regulation of their surface expression than for cytotoxic recognition by NKG2D and emphasise that detailed characterisation of the cell biology of individual NKG2D ligands will be necessary to allow targeted modulation of this system.

The xCELLigence system for real-time and label-free monitoring of cell viability

We describe here the use of the xCELLigence system for label-free and real-time monitoring of cell -viability. The xCELLigence system uses specially designed microtiter plates containing interdigitated gold microelectrodes to noninvasively monitor the viability of cultured cells using electrical impedance as the readout. The continuous monitoring of cell viability by the xCELLigence system makes it possible to distinguish between different perturbations of cell viability, such as senescence, cell toxicity (cell death), and reduced proliferation (cell cycle arrest). In addition, the time resolution of the xCELLigence system allows for the determination of optimal time points to perform standard cell viability assays as well as other end-point assays to understand the mode of action. We have used the WST-1 assay (end-point viability readout), the cell index determination (continuous monitoring of viability by xCELLigence), and the DNA fragmentation assay (end-point apoptosis assay) to systematically examine cytotoxic effects triggered by two cytotoxic compounds with different cell-killing kinetics. Good correlation was observed for viability readouts between WST-1 and cell index. The significance of time resolution by xCELLigence readout is exemplified by its ability to pinpoint the optimal time points for conducting end point viability and apoptosis assays.

Enhanced gene delivery mediated by low molecular weight chitosan/DNA complexes: effect of pH and serum

This study was designed to systematically evaluate the influence of pH and serum on the transfection process of chitosan–DNA complexes, with the objective of maximizing their efficiency. The hydrodynamic diameter of the complexes, measured by dynamic light scattering (DLS), was found to increase with salt and pH from 243 nm in water to 1244 nm in PBS at pH 7.4 and aggregation in presence of 10% serum. The cellular uptake of complexes into HEK 293 cells assessed by flow cytometry and confocal fluorescent imaging was found to increase at lower pH and serum. Based on these data, new methodology were tested and high levels of transfection (>40%) were achieved when transfection was initiated at pH 6.5 with 10% serum for 8–24 h to maximize uptake and then the media was changed to pH 7.4 with 10% serum for an additional 24–40 h period. Cytotoxicity of chitosan/DNA complexes was also considerably lower than Lipofectamine™. Our study demonstrates that the evaluation of the influence of important parameters in the methodology of transfection enables the understanding of crucial physicochemical and biological mechanisms which allows for the design of methodologies maximising transgene expression.

A simple method to measure cell viability in proliferation and cytotoxicity assays

Resazurin dye has been broadly used as indicator of cell viability in several types of assays for evaluation of the biocompatibility of medical and dental materials. Mitochondrial enzymes, as carriers of diaphorase activities, are probably responsible for the transference of electrons from NADPH + H+ to resazurin, which is reduced to resorufin. The level of reduction can be quantified by spectrophotometers since resazurin exhibits an absorption peak at 600 etam and resorufin at 570 etam wavelengths. However, the requirement of a spectrophotometer and specific filters for the quantification could be a barrier to many laboratories. Digital cameras containing red, green and blue filters, which allow the capture of red (600 to 700 etam) and green (500 to 600 etam) light wavelengths in ranges bordering on resazurin and resorufin absorption bands, could be used as an alternative method for the assessment of resazurin and resorufin concentrations. Thus, our aim was to develop a simple, cheap and precise method based on a digital CCD camera to measure the reduction of resazurin. We compared the capability of the CCD-based method to distinguish different concentrations of L929 and normal Human buccal fibroblast cell lines with that of a conventional microplate reader. The correlation was analyzed through the Pearson coefficient. The results showed a strong association between the measurements of the method developed here and those made with the microplate reader (r(2) = 0.996; p < 0.01) and with the cellular concentrations (r(2) = 0.965; p < 0.01). We concluded that the developed Colorimetric Quantification System based on CCD Images allowed rapid assessment of the cultured cell concentrations with simple equipment at a reduced cost.

Ultra-small gadolinium oxide nanoparticles to image brain cancer cells in vivo with MRI

The majority of contrast agents used in magnetic resonance imaging (MRI) is based on the rare-earth element gadolinium. Gadolinium-based nanoparticles could find promising applications in pre-clinical diagnostic procedures of certain types of cancer, such as glioblastoma multiforme. This is one of the most malignant, lethal and poorly accessible forms of cancer. Recent advances in colloidal nanocrystal synthesis have led to the development of ultra-small crystals of gadolinium oxide (US-Gd(2)O(3), 2-3 nm diameter). As of today, this is the smallest and the densest of all Gd-containing nanoparticles. Cancer cells labeled with a sufficient quantity of this compound appear bright in T(1)-weighted MRI images. Here we demonstrate that US-Gd(2)O(3) can be used to label GL-261 glioblastoma multiforme cells, followed by localization and visualization in vivo using MRI. Very high amounts of Gd are efficiently internalized and retained in cells, as confirmed with TEM and ICP-MS. Labeled cells were visualized in vivo at 1.5 T using the chicken embryo model. This is one more step toward the development of "positively contrasted" cell tracking procedures with MRI.

Random co-polymers based on the poloxamer Bayfit® 10WF15 for biomedical applications

Random co-polymers were prepared from the poloxamer Bayfit(®) 10WF15 and their thermal and biological properties analyzed. The poloxamer was characterized, functionalized with methacrylate groups (Bayfit-MA) and further co-polymerized with 2-hydroxyethyl methacrylate (HEMA) with Bayfit-MA feed contents of 1, 5 and 10 wt%. Co-polymers were partially soluble in organic solvents and exhibited a single glass transition temperature indicative of a random monomer distribution in the macromolecular chains. In thermogravimetric studies the co-polymers showed two degradation stages, around 210 and 350 °C, respectively. The thermosensitive behaviour of the poloxamer was studied by turbidimetry. Cloud point temperatures of aqueous solutions of Bayfit(®) 10WF15 (0.5-5 wt%) ranged from 15 to 18 °C and for Bayfit(®) 10WF15 methacrylate (0.5-1 wt%) from 6 to 7 °C. DSC thermograms of hydrated co-polymers showed the typical endothermic peaks with phase transition temperatures close to that of physiological medium. The biocompatibility of initial poloxamer and derivatives was analyzed with human fibroblasts cultures. The IC(50) value of Bayfit(®) 10WF15 was 1.4 mg/ml. Cellular extracts of the co-polymers were not cytotoxic and cellular proliferation and DNA content depended on co-polymer composition.

Functionalization impacts the effects of carbon nanotubes on the immune system of rainbow trout, Oncorhynchus mykiss

Recent studies have demonstrated the potential for manufactured nanomaterials to reach the aquatic environment. There is a need to determine if these materials will have an impact on aquatic species and at what level of exposure. In addition there is a need to develop models to test the potential effects of the multitude of particle types in production on aquatic vertebrates. The purpose of this research was to determine the impact of manufactured nanomaterials on the immune system of an aquatic vertebrate model, the rainbow trout (Oncorhynchus mykiss). We investigated how structure and type of functionalization of manufactured nanomaterials could affect immunotoxicity. To assess immunotoxicity, we used a well-studied trout macrophage primary cell culture system in conjunction with the expression of IL-1β and IFNα for proinflammatory and antiviral gene expression. There was a significant difference among the different carbon nanotube-based nanomaterials in their level of stimulation of IL-1β in macrophage cells and the dose at which they became stimulatory. At concentrations that were sublethal to cells, almost all nanomaterials were stimulatory at some concentration. Single-walled nanotubes and multi-walled nanotubes that were differentially functionalized to be water-soluble, varied in their effects; specifically the concentrations at which they were stimulatory and they were more stimulatory to IL-1β expression compared with unfunctionalized nanotubes. Each functionalized nanotube type caused a dose-dependent response with the lowest exposures (0.05-1.0 μg/ml) having no stimulatory response and at the highest concentrations (5 μg/ml and 10 μg/ml) stimulating a response similar to the positive LPS positive control. Anionic functionalized multi-walled nanotubes and zwitterionic single-walled nanotubes were stimulatory at the lowest dose (0.5 μg/ml). Sodium deoxycholate, often used to suspend nanomaterials, was also tested and was as stimulatory to the immune cells as the nanomaterials. This study is the first report of the effects of nanomaterials on the function of the immune system in a nonmammalian vertebrate. Since the innate immune system is the first to respond to the intrusion of foreign material, analysis of the effects of nanomaterials on cells of the innate immune system should provide valuable information on how these materials are perceived and affect an animal. Ultimately such research will provide the means to determine which nanomaterials are most harmful to aquatic species and how particles may be altered or functionalized to decrease their toxicity.

Biomineralized porous composite scaffolds prepared by chemical synthesis for bone tissue regeneration

Scaffold design is a key factor in the clinical success of bone tissue engineering grafts. To date, no existing single biomaterial used in bone repair and regeneration fulfils all the requirements for an ideal bone graft. In this study hydroxyapatite/polycaprolactone (HA/PCL) composite scaffolds were prepared by a wet chemical method at room temperature. The physico-chemical properties of the composite materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, while scaffold morphology was investigated by scanning electron microscopy (SEM) with energy-dispersive spectroscopy to validate the process used for synthesis. Finally, the response of bone marrow-derived human mesenchymal stem cells (hMSCs) in terms of cell proliferation and differentiation to the osteoblastic phenotype was evaluated using the Alamar blue assay, SEM and alkaline phosphatase activity. Microstructural analysis indicated that the HA particles were distributed homogeneously within the PCL matrix. The biological results revealed that the HA/PCL composite scaffolds are suitable for the proliferation and differentiation of MSCs in vitro, supporting osteogenesis after 15 days. All the results indicate that these scaffolds meet the requirements of materials for bone tissue engineering and could be used for many clinical applications in orthopaedic and maxillofacial surgery.

Performance of the flow cytometric E-screen assay in screening estrogenicity of pure compounds and environmental samples

In vitro estrogenicity screens are believed to provide a first prioritization step in hazard characterization of endocrine disrupting chemicals. When applied to complex environmental matrices or mixture samples, they have been indicated valuable in estimating the overall estrogen-mimicking load. In this study, the performance of an adapted format of the classical E-screen or MCF-7 cell proliferation assay was profoundly evaluated to rank pure compounds as well as influents and effluents of sewage treatment plants (STPs) according to estrogenic activity. In this adapted format, flow cytometric cell cycle analysis was used to allow evaluation of the MCF-7 cell proliferative effects after only 24 h of exposure. With an average EC(50) value of 2 pM and CV of 22%, this assay appears as a sensitive and reproducible system for evaluation of estrogenic activity. Moreover, estrogenic responses of 17 pure compounds corresponded well, qualitatively and quantitatively, with other in vitro and in vivo estrogenicity screens, such as the classical E-screen (R(2)=0.98), the estrogen receptor (ER) binding (R(2)=0.84) and the ER transcription activation assay (R(2)=0.87). To evaluate the applicability of this assay for complex samples, influents and effluents of 10 STPs covering different treatment processes, were compared and ranked according to estrogenic removal efficiencies. Activated sludge treatment with phosphorus and nitrogen removal appeared most effective in eliminating estrogenic activity, followed by activated sludge, lagoon and filter bed. This is well in agreement with previous findings based on chemical analysis or biological activity screens. Moreover, ER blocking experiments indicated that cell proliferative responses were mainly ER mediated, illustrating that the complexity of the end point, cell proliferation, compared to other ER screens, does not hamper the interpretation of the results. Therefore, this study, among other E-screen studies, supports the use of MCF-7 cell proliferation as estrogenicity screen for pure compounds and complex samples.

Comparison of potency assays using different read-out systems and their suitability for quality control

In this study, three of the most commonly used non-radioactive read-out systems for bioassays, the tetrazolium salt MTS/PMS, the fluorescent dye Alamar Blue and the ATP bioluminescence assay were compared regarding their suitability for quality control purposes. In this regard, three different potency assays using murine CTLL-2, as well as human DiFi and Kit 225 cells were performed. No major differences regarding accuracy and precision were detected between the different read-out systems. Both workload and hands-on time were similar for all three assays used. All read-out systems were suitable for use in quality control. However, luminescence and fluorescence techniques were much more sensitive than the colorimetric system. The first two could determine approximately ten times lower drug concentrations, and the assay could be performed by using considerably lower cell numbers. Moreover, in two of the three potency assays, the luminescence and fluorescence read-out systems provided higher signal to noise ratios leading to a higher precision of the assays. Regarding the comparison of the luminescence and fluorescence system, the ATP assay has the advantage to be much faster than the Alamar Blue assay. Consequently, in this study, the luminescence technique turned out to be the most advantageous of the three read-out systems.

Selective induction of host genes by MVA-B, a candidate vaccine against HIV/AIDS

The aim of this study was to define the effects on antigen-presenting cells of the expression of HIV antigens from an attenuated poxvirus vector. We have analyzed the transcriptional changes in gene expression following infection of human immature monocyte-derived dendritic cells (DC) with recombinant modified vaccinia virus Ankara (MVA) expressing the genes encoding the gp120 and Gag-Pol-Nef antigens of HIV type 1 clade B (referred to as MVA-B) versus parental MVA infection. Using microarray technology and real-time reverse transcription-PCR, we demonstrated that the HIV proteins induced the expression of cytokines, cytokine receptors, chemokines, chemokine receptors, and molecules involved in antigen uptake and processing, including major histocompatibility complex (MHC) genes. Levels of mRNAs for interleukin-1, beta interferon, CCR8, and SCYA20 were higher after HIV antigen production. MVA-B infection also modulated the expression of antigen processing and presentation genes: the gene for MICA was upregulated, whereas those for HLA-DRA and HSPA5 were downregulated. Indeed, the increased expression of the gene for MICA, a glycoprotein related to major histocompatibility complex class I molecules, was shown to enhance the interaction between MVA-B-infected target cells and cytotoxic lymphocytes. The expression profiles of the genes for protein kinases such as JAK1 and IRAK2 were activated after HIV antigen expression. Several genes included in the JAK-STAT and mitogen-activated protein kinase signaling pathways were regulated after HIV antigen expression. Our findings provide the first gene signatures in DC of a candidate MVA-B vaccine expressing four HIV antigens and identified the biological roles of some of the regulatory genes, like that for MICA, which will help in the design of more effective MVA-derived vaccines.

Effects of fumaric acids on cuprizone induced central nervous system de- and remyelination in the mouse

Background

Fumaric acid esters (FAE) are a group of compounds which are currently under investigation as an oral treatment for relapsing-remitting multiple sclerosis. One of the suggested modes of action is the potential of FAE to exert a neuroprotective effect.

Methodology/Principal Findings

We have investigated the impact of monomethylfumarate (MMF) and dimethylfumaric acid (DMF) on de- and remyelination using the toxic cuprizone model where the blood-brain-barrier remains intact and only scattered T-cells and peripheral macrophages are found in the central nervous system (CNS), thus excluding the influence of immunomodulatory effects on peripheral immune cells. FAE showed marginally accelerated remyelination in the corpus callosum compared to controls. However, we found no differences for demyelination and glial reactions in vivo and no cytoprotective effect on oligodendroglial cells in vitro. In contrast, DMF had a significant inhibitory effect on lipopolysaccharide (LPS) induced nitric oxide burst in microglia and induced apoptosis in peripheral blood mononuclear cells (PBMC).

Conclusions

These results contribute to the understanding of the mechanism of action of fumaric acids. Our data suggest that fumarates have no or only little direct protective effects on oligodendrocytes in this toxic model and may act rather indirectly via the modulation of immune cells.

Effects of magnesium alloys extracts on adult human bone marrow-derived stromal cell viability and osteogenic differentiation

In this study, adult human bone marrow-derived stromal cells (hBMSCs) were cultured in extracts of magnesium (Mg) and the Mg alloys AZ91D and NZ30K for 12 days. We studied the indirect effects of Mg alloys on hBMSC viability. Alkaline phosphatase activity and the expression of osteogenic differentiation marker genes were used to evaluate the effects of the Mg alloys on the osteogenic differentiation of hBMSCs. The results indicate that <or=10 mM concentration of Mg in the extracts did not inhibit the viability and osteogenic differentiation of hBMSCs. However, the results suggest that the high pH of the extracts, which is a result of the rapid corrosion of Mg and the Mg alloys, is unfavorable to the viability and osteogenic differentiation of hBMSCs.

A locked nucleic acid antisense oligonucleotide (LNA) silences PCSK9 and enhances LDLR expression in vitro and in vivo

Background

The proprotein convertase subtilisin/kexin type 9 (PCSK9) is an important factor in the etiology of familial hypercholesterolemia (FH) and is also an attractive therapeutic target to reduce low density lipoprotein (LDL) cholesterol. PCSK9 accelerates the degradation of hepatic low density lipoprotein receptor (LDLR) and low levels of hepatic PCSK9 activity are associated with reduced levels of circulating LDL-cholesterol.

Methodology/Principal Findings

The present study presents the first evidence for the efficacy of a locked nucleic acid (LNA) antisense oligonucleotide (LNA ASO) that targets both human and mouse PCSK9. We employed human hepatocytes derived cell lines HepG2 and HuH7 and a pancreatic mouse β-TC3 cell line known to express high endogenous levels of PCSK9. LNA ASO efficiently reduced the mRNA and protein levels of PCSK9 with a concomitant increase in LDLR protein levels after transfection in these cells. In vivo efficacy of LNA ASO was further investigated in mice by tail vein intravenous administration of LNA ASO in saline solution. The level of PCSK9 mRNA was reduced by ∼60%, an effect lasting more than 16 days. Hepatic LDLR protein levels were significantly up-regulated by 2.5–3 folds for at least 8 days and ∼2 fold for 16 days. Finally, measurement of liver alanine aminotransferase (ALT) levels revealed that long term LNA ASO treatment (7 weeks) does not cause hepatotoxicity.

Conclusion/Significance

LNA-mediated PCSK9 mRNA inhibition displayed potent reduction of PCSK9 in cell lines and mouse liver. Our data clearly revealed the efficacy and safety of LNA ASO in reducing PCSK9 levels, an approach that is now ready for testing in primates. The major significance and take home message of this work is the development of a novel and promising approach for human therapeutic intervention of the PCSK9 pathway and hence for reducing some of the cardiovascular risk factors associated with the metabolic syndrome.

Differential mechanisms of shedding of the glycosylphosphatidylinositol (GPI)-anchored NKG2D ligands

Tumor cells release NKG2D ligands to evade NKG2D-mediated immune surveillance. The purpose of our investigation was to explore the cellular mechanisms of release used by various members of the ULBP family. Using biochemical and cellular approaches in both transfectant systems and tumor cell lines, this paper shows that ULBP1, ULBP2, and ULBP3 are released from cells with different kinetics and by distinct mechanisms. Whereas ULBP2 is mainly shed by metalloproteases, ULBP3 is abundantly released as part of membrane vesicles known as exosomes. Interestingly, exosomal ULBP3 protein is much more potent for down-modulation of the NKG2D receptor than soluble ULBP2 protein. This is the first report showing functionally relevant differences in the biochemistry of the three members of the ULBP family and confirms that in depth study of the biochemical features of individual NKG2D ligands will be necessary to understand and manipulate the biology of these proteins for therapy.

Biodegradable Sirolimus-loaded Poly(lactide) Nanoparticles as Drug Delivery System for the Prevention of In-Stent Restenosis in Coronary Stent Application

The administration of drugs using biodegradable polymer nanoparticles as carriers has generated immense interest due to their excellent biocompatibility and the prolonged drug release. The scope of this work was to determine the applicability of sirolimus-loaded biodegradable poly(D,L-lactide) (PDLLA) nanoparticles as drug carriers to prevent restenotic processes after stent implantation. The average 250 nm sized 20%(w/w) sirolimus-loaded nanoparticles were extensively characterized with regard to in vitro degradation, biocompatibility and in vitro drug release. The particles show biphasic release kinetics consisting of a short burst release of 50%(w/w) sirolimus payload, followed by a longer, slower release phase, which are desirable for the application as a drug delivery carrier. All presented results exhibit the potential of sirolimus-loaded PDLLA nanoparticles as promising local and sustained drug delivery systems administered intraluminally to reduce in-stent restenosis after stent implantation.

Discrepancies between metabolic activity and DNA content as tool to assess cell proliferation in cancer research

Cell proliferation is a critical and frequently studied feature of molecular biology in cancer research. Therefore, various assays are available using different strategies to measure cell proliferation. Metabolic assays such as AlamarBlue, water-soluble tetrazolium salt and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, which were originally developed to determine cell toxicity, are used to assess cell numbers. Additionally, proliferative activity can be determined by quantification of DNA content using fluorophores such as CyQuant and PicoGreen. Referring to data published in high ranking cancer journals, these assays were applied in 945 publications over the past 14 years to examine the proliferative behaviour of diverse cell types. In these studies, however, mainly metabolic assays were used to quantify changes in cell growth yet these assays may not accurately reflect cellular proliferation rates due to a miscorrelation of metabolic activity and cell number. Testing this hypothesis, we compared the metabolic activity of different cell types, human cancer cells and primary cells, over a time period of 4 days using AlamarBlue and the fluorometric assays CyQuant and PicoGreen to determine their DNA content. Our results show certain discrepancies in terms of over-estimation of cell proliferation with respect to the metabolic assay in comparison to DNA binding fluorophores.

Understanding the gap between the estrogenicity of an effluent and its real impact into the wild

To study the reliability between in vitro and in vivo data collected downstream 2 sewage treatment plants (STP) as well as from bleached kraft mill industry (BKME), 5 rivers (3 impacted and 2 references) were investigated in the Walloon region (southern of Belgium). For the in vitro part of the work, water samples were collected to measure the estrogenicity of the 'out' effluent compared to reference sample point by MCF-7 assay. Results indicated significant estrogenicity of effluents from STP and BKME and a weak estrogenicity in reference sites. However, estradiol equivalents (EEQ) estimated into rivers were probably too low to impact wild population. Chemical analysis of 13 compounds of interest indicated that extraction procedure used in this study gave low recoveries of estrogen-like xenobiotics, leading to probably under-estimated MCF-7 responses. Surprisingly, a full scan mode has revealed an unexpected compound in the sample of BKME which was: 7-isopropyl-1,1,4a-trimethyl-1,2,3,4a,9,10,10a-octahydrophenanthrene, a product of pulp mill manufacture. In parallel to in vitro, in vivo assessment of estrogenic impact of effluent was followed on the gudgeon (Gobio gobio). Samples were achieved during 2 different periods of the reproductive cycle, resting period (RP) and pre-spawning period (pSP). Unspecific physiological parameters to estrogenic exposure (gonadosomatic index and systematic testis cell counting) displayed no significant differences related to endocrine disruption of the reproductive tract, only differences were correlated with the reproductive state of fish (RP versus pSP). Concerning the potent biomarker of estrogen exposure, vitellogenin (vtg), only basal induction was revealed but not related to estrogenic exposure. Nevertheless, vtg over-expression was found for male fish presenting a feminization of the reproductive tract captured downstream the STP station of Wégnez in the Vesdre River. Intersexuality, another indicator of the estrogenicity impact in fish, was observed in every site. Actually, ovotestis was systematically formed by protoplasmic oocyte observed in low percentage in every group analysed (impacted and references). Moreover, in fish captured in Wégnez, oocyte diameter was significantly higher compared to the other groups. In this study, only moderate to none impact in population of gudgeon was noticed. Moreover, in this case no discrepancy between in vitro and vivo was viewed although both approaches revealed gaps in monitoring effluent incidence into the environment. We should remain careful in the interpretation when only partial approaches are used in order to characterize impact in the aquatic milieu.

Natural killer cell cytotoxicity is suppressed by exposure to the human NKG2D ligand MICA*008 that is shed by tumor cells in exosomes

The MHC class I-related chain (MIC) A and MICB ligands for the activating receptor NKG2D can be shed from tumor cells, and the presence of these soluble molecules in sera is related with compromised immune response and progression of disease. Recently, thiol disulphide isomerases and members of the ADAM (a disintegrin and metalloproteinase) gene family were identified as key enzymes in mediating MICA/B shedding from cells. Here, we report shedding of the most frequently expressed MICA allele in human populations (MICA*008) into exosomes, small membrane vesicles that are secreted upon fusion with the plasma membrane. Although similar to other MICA/B molecules in the extracellular domain, the predicted transmembrane and cytoplasmic domains of MICA*008 are quite different, and this difference seemed to be critical for the mode of release from tumor cells. Treatment of natural killer (NK) cells with exosomes containing MICA*008 molecules not only triggered downregulation of NKG2D from the cell surface but also provoked a marked reduction in NK cytotoxicity that is independent of NKG2D ligand expression by the target cell. Our findings reveal a mechanism of NK suppression in cancer that may facilitate immune escape and progression.

Halogenated fatty acid amides and cyclic depsipeptides from an eastern Caribbean collection of the cyanobacterium Lyngbya majuscula

A lipophilic extract of an eastern Caribbean collection of Lyngbya majuscula yielded two new halogenated fatty acid amides, grenadamides B (1) and C (2), and two new depsipeptides, itralamides A (3) and B (4), along with the known compounds hectochlorin and deacetylhectochlorin. The recently reported depsipeptide carriebowmide (5) was also present in the extract and isolated as its sulfone artifact (6). Compounds 1-4 were identified by spectroscopic methods. The configurations of the amino acid residues of 3, 4, and 6 were determined by LC-MS analyses of diastereomeric derivatives of the acid hydrolysates (advanced Marfey's method). Based on the configurational analysis of 6, in direct comparison with authentic carriebowmide (5), a minor structural revision of 5 is proposed. Compounds 1 and 2 displayed marginal activity against the beet armyworm (Spodoptera exigua). Compounds 1-4 and 6 were assessed for general cell toxicity in human embryonic kidney (HEK293) cells. Only itralamide B (4) displayed significant cytotoxicity, showing an IC(50) value of 6 +/- 1 muM.

MTS dye based colorimetric CTLL-2 cell proliferation assay for product release and stability monitoring of interleukin-15: assay qualification, standardization and statistical analysis

A colorimetric cell proliferation assay using soluble tetrazolium salt [(CellTiter 96(R) Aqueous One Solution) cell proliferation reagent, containing the (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) and an electron coupling reagent phenazine ethosulfate], was optimized and qualified for quantitative determination of IL-15 dependent CTLL-2 cell proliferation activity. An in-house recombinant Human (rHu)IL-15 reference lot was standardized (IU/mg) against an international reference standard. Specificity of the assay for IL-15 was documented by illustrating the ability of neutralizing anti-IL-15 antibodies to block the product specific CTLL-2 cell proliferation and the lack of blocking effect with anti-IL-2 antibodies. Under the defined assay conditions, the linear dose-response concentration range was between 0.04 and 0.17ng/ml of the rHuIL-15 produced in-house and 0.5-3.0IU/ml for the international standard. Statistical analysis of the data was performed with the use of scripts written in the R Statistical Language and Environment utilizing a four-parameter logistic regression fit analysis procedure. The overall variation in the ED(50) values for the in-house reference standard from 55 independent estimates performed over the period of 1year was 12.3% of the average. Excellent intra-plate and within-day/inter-plate consistency was observed for all four parameter estimates in the model. Different preparations of rHuIL-15 showed excellent intra-plate consistency in the parameter estimates corresponding to the lower and upper asymptotes as well as to the 'slope' factor at the mid-point. The ED(50) values showed statistically significant differences for different lots and for control versus stressed samples. Three R-scripts improve data analysis capabilities allowing one to describe assay variations, to draw inferences between data sets from formal statistical tests, and to set up improved assay acceptance criteria based on comparability and consistency in the four parameters of the model. The assay is precise, accurate and robust and can be fully validated. Applications of the assay were established including process development support, release of the rHuIL-15 product for pre-clinical and clinical studies, and for monitoring storage stability.

Biologic assessment of antiseptic mouthwashes using a three-dimensional human oral mucosal model

BACKGROUND

The biologic safety profile of oral health care products is often assumed on the basis of simplistic test models such as monolayer cell culture systems. We developed and characterized a tissue-engineered human oral mucosal model, which was proven to represent a potentially more informative and more clinically relevant alternative for the biologic assessment of mouthwashes. The aim of this study was to evaluate the biologic effects of alcohol-containing mouthwashes on an engineered human oral mucosal model.

METHODS

Three-dimensional (3D) models were engineered by the air/liquid interface culture technique using human oral fibroblasts and keratinocytes. The models were exposed to phosphate buffered saline (negative control), triethylene glycol dimethacrylate (positive control), cola, and three types of alcohol-containing mouthwashes. The biologic response was recorded using basic histology; a cell proliferation assay; 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tissue-viability assay; transmission electron microscopy (TEM) analysis; and the measurement of release of interleukin (IL)-1beta by enzyme-linked immunosorbent assay.

RESULTS

Statistical analysis showed that there was no significant difference in tissue viability among the mouthwashes, cola, and negative control groups. However, exposure to the positive control significantly reduced the tissue viability and caused severe cytotoxic epithelial damage as confirmed by histology and TEM analysis. A significant increase of IL-1beta release was observed with the positive control and, to a lesser extent, with two of the tested mouthrinses.

CONCLUSIONS

The 3D human oral mucosal model can be a suitable model for the biologic testing of mouthwashes. The alcohol-containing mouthwashes tested in this study do not cause significant cytotoxic damage and may slightly stimulate IL-1beta release.

Biocompatibility of Resin-based Dental Materials

Oral and mucosal adverse reactions to resin-based dental materials have been reported. Numerous studies have examined the biocompatibility of restorative dental materials and their components, and a wide range of test systems for the evaluation of the biological effects of these materials have been developed. This article reviews the biological aspects of resin-based dental materials and discusses the conventional as well as the new techniques used for biocompatibility assessment of dental materials.

The therapeutic potential of recombinant BCG expressing the antigen S1PT in the intravesical treatment of bladder cancer

PURPOSE

Bacillus Calmette-Guerin (BCG) continues to be employed as the most effective immunotherapy against superficial bladder cancer. We have developed an rBCG-S1PT strain that induces a stronger cellular immune response than BCG. This preclinical study was designed to test the potential of rBCG-S1PT as an immunotherapeutic agent for intravesical bladder cancer therapy.

MATERIALS AND METHODS

A tumor was induced in C57BL/6 mice after chemical cauterization of the bladder and inoculation of the tumor cell line MB49. Next, mice were treated by intravesical instillation with BCG, rBCG-S1PT, or PBS once a week for 4 weeks. After 35 days, the bladders were removed and weighed, Th1 (IL-2, IL-12, INOS, INF-gamma, TNF-alpha), and Th2 (IL-5, IL-6, IL-10, TGF-beta) cytokine mRNA responses in individual mice bladders were measured by quantitative real time PCR, and the viability of MB49 cells in 18-hour coculture with splenocytes from treated mice was assessed. In an equivalent experiment, animals were observed for 60 days to quantify their survival.

RESULTS

Both BCG and rBCG-S1PT immunotherapy resulted in bladder weight reduction, and rBCG-S1PT increased survival time compared with the control group. There were increases in TNF-alpha in the BCG treated group, as well as increases in TNF-alpha and IL-10 mRNA in the rBCG-S1PT group. The viability of MB49 cells cocultured with splenocytes from rBCG-S1PT-treated mice was lower than in both the BCG and control groups.

CONCLUSIONS

rBCG-S1PT therapy improved outcomes and lengthened survival times. These results indicate that rBCG could serve as a useful substitute for wild-type BCG.

Chemical genetic screening of KRAS-based synthetic lethal inhibitors for pancreatic cancer

Pancreatic cancer is one of the deadliest diseases largely due to difficulty in early diagnosis and the lack of effective treatments. KRAS is mutated in more than 90% of pancreatic cancer patients, and oncogenic KRAS contributes to pancreatic cancer tumorigenesis and progression. In this report, using an oncogenic KRASV12-based pancreatic cancer cell model, we developed a chemical genetic screen to identify small chemical inhibitors that selectively target pancreatic cancer cells with gain-of-function KRAS mutation. After screening ~3,200 compounds, we identified one compound that showed selective synthetic lethality against the KRASV12 transformed human pancreatic ductal epithelial cell over its isogenic parental cell line. These selective KRASV12-synthetic lethal compounds may serve as leads for subsequent development of clinically-effective treatments for pancreatic cancer.

A phosphatidylserine species inhibits a range of TLR- but not IL-1beta-induced inflammatory responses by disruption of membrane microdomains

TLRs detect conserved molecular patterns that are unique to microbes, enabling tailored responses to invading pathogens and modulating a multitude of immunopathological conditions. We investigated the ability of a naturally occurring stearoyl-arachidonoyl form of phosphatidylserine (SAPS) to inhibit the proinflammatory effects of TLR agonists in models of inflammation investigating the interaction of leukocytes with epithelial and endothelial cells. The responses to LPS of both epithelial and endothelial cells were highly amplified in the presence of PBMCs. Coincubation with SAPS markedly inhibited activation of cocultures by LPS, principally through inhibition of the TLR4 signaling pathway in PBMCs; however, this was not through downmodulation of TLR4 or coreceptor expression, nor was IL-1beta-induced cytokine release affected. SAPS also impaired Pam(3)CSK(4) (TLR2/1), Gardiquimod (TLR7/8), and Streptococcus pneumoniae-induced cytokine release, but had only modest effects on poly(I:C) (TLR3)-induced responses. Fluorescence resonance energy transfer analysis of molecular associations revealed that SAPS disrupted the association of both TLR4 and TLR2 with their respective membrane partners that are required for signaling. Thus, our data reinforce the existence and importance of cooperative networks of TLRs, tissue cells, and leukocytes in mediating innate immunity, and identify a novel disrupter of membrane microdomains, revealing the dependence of TLR signaling on localization within these domains.