Down-regulation of the expression of cyclooxygenase-2 and prostaglandin E2 by interleukin-4 is mediated via a reduction in the expression of prostanoid EP4 receptors in HCA-7 human colon cancer cells.

Chronic inflammatory bowel disease (IBD), which is characterized by prolonged inflammation of the gastrointestinal tract is associated with an increased risk of colorectal cancer. Recent studies revealed that the pathology of IBD is caused by hyperactivated immune responses mediated by differentiated CD4+ naïve helper T cells, such as Th1 and Th17 cells, but not Th2 cells. The human E-type prostanoid 4 (EP4) receptor and its pathways have also been implicated in and/or associated with the early developmental stages of colorectal cancer along with increases in the levels of prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2), the hallmarks of colorectal carcinogenesis. In the present study, using an in silico analysis and pharmacological experiments, we demonstrated that interleukin (IL)-4, a signature cytokine of Th2 cells, down-regulated the expression of COX-2 and PGE2 in the human colon cancer cell line, HCA-7. This result may be attributed to a reduction in the expression of prostanoid EP4 receptors through the induction of hypoxia inducible factor-1α via the interleukin-4 receptor-stimulated activation of signal transducer and activator of transcription 6. However, another major Th2 cytokine IL-13 had no effect on the expression of COX-2 or prostanoid EP4 receptors in HCA-7 cells. Therefore, instead of the hyperactivation of Th1/Th17 cells, the deactivation/down-regulation of Th2 cells followed by a decrease in the production of IL-4 in IBD may play a role in the cancerous transformation of cells, at least in prostanoid EP4 receptor-overactivated tumorigenesis.

A Previously Unknown Drug-Drug Interaction Is Suspected in Delayed Elimination of Plasma Methotrexate in High-Dose Methotrexate Therapy.

Background: High-dose methotrexate (HD-MTX) therapy is widely implemented for leukemia, osteosarcoma, and lymphoma. Although various measures have been taken to avoid toxicity from high serum MTX concentrations, there are many cases of delayed elimination of MTX. Objective: We suspected that delayed elimination of serum MTX was caused by unknown interactions between MTX and concomitant drugs. Methods: Concerning concomitant drugs in the case of delayed elimination of MTX, we performed screening tests in 35 patients who had undergone HD-MTX therapy. We then investigated the risk factors for delayed MTX elimination in 94 patients with leukemia, lymphoma, or osteosarcoma retrospectively. Results: The percentages of concomitant use of Stronger Neo-Minophagen C (SNMC), a glycyrrhizin preparation, and vincristine were higher in the delayed group. The percentage of delayed MTX elimination in patients receiving HD-MTX therapy was 41%. Multiple logistic regression analysis revealed that the concomitant use of SNMC solely was a significant risk factor for delayed MTX (odds ratio = 12.20; 95% CI = 1.06-139.84). Conclusion and Relevance: Concomitant use of SNMC was shown to be related to delayed elimination of serum MTX, and our results suggested a previously unknown drug-drug interaction between MTX and SNMC.

Short chain fatty acid butyrate uptake reduces expressions of prostanoid EP4 receptors and their mediation of cyclooxygenase-2 induction in HCA-7 human colon cancer cells.

Microbiota produce short chain fatty acids (SCFAs), which are known to maintain gut homeostasis, by the fermentation of dietary fiber in the human colon. Among SCFAs, butyrate has been considered as the most physiologically effective SCFA in colorectal epithelial cells for growth and differentiation. Here we show that the E-type prostanoid 4 (EP4) receptor expression level is regulated by different concentrations of butyrate, but not by other SCFAs, in human colon cancer HCA-7 cells, through sodium-coupled monocarboxylate transporter-1 (SMCT-1)-mediated uptake followed by the activation of histone acetyltransferase: cAMP response element binding protein-binding protein/p300. Of particular interest, the prostanoid EP4 receptors are known to be expressed in normal colorectal crypt epithelial cells and maintain intestinal homeostasis by preserving mucosal integrity, while they are also known to be involved in the early stage of carcinogenesis. Thus, the links between butyrate and the expression of prostanoid EP4 receptors are both important factors for maintaining homeostasis. Based on in silico analysis, almost half of colorectal cancer tissues have lost the expression of SMCT-1 mRNA when compared with healthy corresponding tissues. Therefore, with the collapse of homeostasis systems such as a decrease in the concentration of butyrate in colorectal tissues, or reduced butyrate uptake, there is a possibility of early stage colorectal cancer development; the transformation of normal cells to the cancerous phenotype may be due to the overexpression of prostanoid EP4 receptors followed by excessive cyclooxygenase-2 induction, which are caused by a reduced amount of butyrate and/or its uptake, in/around colorectal epithelial cells.

Species compositions of terrestrial isopods in public parks of a commuter town in Japan.

The species compositions of terrestrial isopod assemblages in 150 public parks in a commuter town in Japan were investigated. Eleven species of terrestrial isopods were present, of which seven were considered native or oriental species, and four were exotic species originally distributed in the Mediterranean and European regions. An exotic species Armadillidiumvulgare Latreille, 1804 was found in all parks. Logistic model analysis indicated that the surrounding land use affected the distributions of three native species, Burmoniscuskathmandius (Schmalfuss, 1983), Ligidiumkoreanum Flasarova, 1972, and Mongoloniscuskoreanus Verhoeff, 1930, indicating that landscape properties are important factors that limit the distributions of terrestrial isopods. The present study also showed that the public parks surrounded by forests or semi-natural environments in a commuter town provide habitats for native terrestrial isopods.

Oxygen concentration dependence of lipid peroxidation and lipid-derived radical generation: application of profluorescent nitroxide switch.

Lipid-derived radicals and peroxides are involved in the pathogenesis of oxidative stress diseases and, although lipid peroxide production is a required reaction between a lipid radical and molecular oxygen, a useful lipid radical detection method has remained tentative. Also, the effect of oxygen concentration on lipid peroxide production must be considered because of the hypoxic conditions in cancer and ischemic regions. In this study, the focus was on nitroxide reactivity, which allows spin trapping with carbon-centred radicals via radical-radical reactions and fluorophore quenching through interactions with nitroxide's unpaired electron. Thus, the aim here was to demonstrate a useful detection method for lipid-derived radicals as well as to clarify the effects of oxygen concentration on lipid peroxide production using profluorescent nitroxide. This latter compound reacted with lipid-derived radicals in a manner inversely dependent on oxygen concentration, resulting in fluorescence due to alkoxyamine formation and, conversely, lipid peroxide concentrations decreased with lower oxygen in the reaction system. Furthermore, nitroxide inhibited lipid peroxide production and stopped oxygen consumption in the same solution. These results suggested that the novel application of profluorescent nitroxide could directly and sensitively detect lipid-derived radicals and that radical and peroxide production were dependent on oxygen concentration.

Structural concept of nitroxide as a lipid peroxidation inhibitor.

Nitroxides have antioxidative activities toward lipid peroxidation, but the influence of steric factors is not known. We synthesized alkyl-substituted nitroxides at the α-position of the N-O moiety to enhance lipophilicity and the bulk effect. There was good correlation between the IC(50) and lipophilicity (log P(o/w)) of nitroxides with use of the thiobarbituric acid-reactive substances (TBARS) assay. Furthermore, an inhibitory effect on the TBARS assay was dependent upon the number and length of alkyl groups, though nitroxides had almost identical lipophilicity.

Autonomic nervous system driven cardiomyocytes in vitro.

Rat superior cervical ganglia (SCG), which are sympathetic ganglia, neurons and ventricular myocytes (VMs) were co-cultured separately in a minichamber placed on a microelectrode-array (MEA) substrate. The minichamber was fabricated photolithographically and had 2 compartments, 16 microcompartments and 8 microconduits. The SCG neurons were seeded into one of the compartments and all of the microcompartments using a glass pipette controlled by a micromanipulator and a microinjector. The VMs were seeded into the other compartment. Three days after seeding of the VMs, the neurites of the SCG neurons had connected with the VMs via the microconduits. Electrical stimulations, trains of biphasic square pulses, were applied to the SCG neurons in the microcompartments using 16 electrodes. Evoked responses were observed in several electrodes while electrical stimulation was applied to the SCG neurons. According to the two-way analysis of variance (ANOVA), the beat rate after electrical stimulation was affected by the frequency and the number of the stimulation pulses. These results suggest that pulse number and the frequency of the electrical stimulation contribute to modulation of the beat rate of the cardiomyocytes.

In vivo evaluation of novel nitroxyl radicals with reduction stability.

Nitroxyl radicals (nitroxide) have great potential advantages as spin probes, antioxidants, contrast agents, and radiation-protecting agents. However, they are readily reduced by reductants in cells and lose their paramagnetic nature. Recently, tetraethyl-substituted nitroxyl radicals have been reported to have high stability toward reduction by ascorbic acid (AsA). We report the general considerations of tetraethyl nitroxyl radicals for in vivo application. The reason for the low reactivity to AsA reduction was the positive value of Gibbs energy between the tetraethyl nitroxyl radical and AsA. Further, these compounds had an inhibitory effect on lipid peroxidation despite having AsA resistance. They had low antiproliferative effects in HepG2 cells and HUVECs and did not have a lowering effect on blood pressure in animals. Further, after intravenous injection, the ESR signal intensities of tetraethyl-substituted piperidine nitroxyl radicals were very stable in mice over 20 min. These results suggest that tetraethyl-substituted nitroxyl radicals have stability against bioreduction with reductants such as AsA and confer onto them features as antioxidants and paramagnetic tracers/contrast agents. Hence, they will be useful in identifying the foci of oxidative stress in vivo using redox-based imaging approaches.

Conformation and molecular dynamics of single polystyrene chain confined in coordination nanospace.

Molecules confined in nanospaces will have distinctly different properties to those in the bulk state because of the formation of specific molecular assemblies and conformations. We studied the chain conformation and dynamics of single polystyrene (PSt) chains confined in highly regular one-dimensional nanochannels of a porous coordination polymer [Zn 2(bdc) 2ted] n ( 1; bdc = 1,4-benzenedicarboxylate, ted = triethylenediamine). Characterization by two-dimensional (2D) heteronuclear (1)H- (13)C NMR gave a direct demonstration of the nanocomposite formation and the intimacy between the PSt and the pore surfaces of 1. Calorimetric analysis of the composite did not reveal any glass transition of PSt, which illustrates the different nature of the PSt encapsulated in the nanochannels compared with that of bulk PSt. From N 2 adsorption measurements, the apparent density of PSt in the nanochannel was estimated to be 0.55 g cm (-3), which is much lower than that of bulk PSt. Results of a solid-state (2)H NMR study of the composite showed the homogeneous mobility of phenyl flipping with significantly low activation energy, as a result of the encapsulation of single PSt chains in one-dimensional regular crystalline nanochannels. This is also supported by molecular dynamics (MD) simulations.

Radical polymerisation of styrene in porous coordination polymers.

The first radical polymerisation of styrene in porous coordination polymers has been carried out, providing stable propagating radicals (living radicals), and a specific space effect of the host frameworks on the monomer reactivity is demonstrated.