• IMMUNE NETWORK
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• v.3 no.3
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• pp.201-210
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• 2003

Objective: The role of prostaglandin $E_2$ (PGE2) in the etiopathogenesis of immune and inflammatory diseases has become the subject of recent debate. To determine the role of PGE2 in rheumatoid arthritis (RA), we tested the effect of exogenous PGE2 on the production of cyclooxygenase-2 (COX-2) by rheumatoid synoviocytes. Methods: Fibroblast-like synoviocytes (FLS) were prepared from the synovial tissues of RA patients, and cultured in the presence of PGE2. The COX-2 mRNA and protein expression levels were determined by RT-PCR and Western blot analysis, respectively. The PGE2 receptor subtypes in the FLS were analyzed by RT-PCR. Electrophoretic mobility shift assay (EMSA) was used to measure the NF-${\kappa}B$ binding activity for COX-2 transcription. The in vivoeffect of PGE2 on the development of arthritis was also tested in collagen induced arthritis (CIA) animals. Results: PGE2 ($10^{-11}$ to $10^{-5}M$) dose-dependently inhibited the expression of COX-2 mRNA and the COX-2 protein stimulated with IL-$1{\beta}$, but not COX-1 mRNA. NS-398, a selective COX-2 inhibitor, displayed an additive effect on PGE2-induced COX-2 downregulation. The FLS predominantly expressed the PGE2 receptor (EP) 2 and EP4, which mediated the COX-2 suppression by PGE2. Treatment with anti-IL-10 monoclonal antibodies partially reversed the PGE2-induced suppression of COX-2 mRNA, suggesting that IL-10 may be involved in modulating COX-2 by PGE2. Experiments using an inducer and an inhibitor of cyclic AMP (cAMP) suggest that cAMP is the major intracellular signal that mediates the regulatory effect of PGE2 on COX-2 expression. EMSA revealed that PGE2 inhibited the binding of NF-${\kappa}B$ in the COX-2 promoter via a cAMP dependent pathway. In addition, a subcutaneous injection of PGE2 twice daily for 2 weeks significantly reduced the incidence and severity of CIA as well as the production of IgG antibodies to type II collagen. Conclusion: Our data suggest that overproduced PGE2 in the RA joints may function as an autocrine regulator of its own synthesis by inhibiting COX-2 production and may, in part, play an anti-inflammatory role in the arthritic joints.

• BMB Reports
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• v.38 no.6
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• pp.633-638
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• 2005

Biosynthesis of prostanoids is regulated by three sequential enzymatic steps, namely phospholipase $A_2$ enzymes, cyclooxygenase (COX) enzymes, and various lineage-specific terminal prostanoid synthases. Prostaglandin E synthase (PGES), which isomerizes COX-derived $PGH_2$ specifically to $PGE_2$, occurs in multiple forms with distinct enzymatic properties, expressions, localizations and functions. Two of them are membrane-bound enzymes and have been designated as mPGES-1 and mPGES-2. mPGES-1 is a perinuclear protein that is markedly induced by proinflammatory stimuli, is down-regulated by anti inflammatory glucocorticoids, and is functionally coupled with COX-2 in marked preference to COX-1. Recent gene targeting studies of mPGES-1 have revealed that this enzyme represents a novel target for anti-inflammatory and anti-cancer drugs. mPGES-2 is synthesized as a Golgi membrane-associated protein, and the proteolytic removal of the N-terminal hydrophobic domain leads to the formation of a mature cytosolic enzyme. This enzyme is rather constitutively expressed in various cells and tissues and is functionally coupled with both COX-1 and COX-2. Cytosolic PGES (cPGES) is constitutively expressed in a wide variety of cells and is functionally linked to COX-1 to promote immediate $PGE_2$ production. This review highlights the latest understanding of the expression, regulation and functions of these three PGES enzymes.

• Parasites, Hosts and Diseases
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• v.53 no.5
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• pp.641-645
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• 2015

Fascioliasis, a food-borne trematode zoonosis, is a disease primarily in cattle and sheep and occasionally in humans. Water dropwort (Oenanthe javanica), an aquatic perennial herb, is a common second intermediate host of Fasciola, and the fresh stems and leaves are widely used as a seasoning in the Korean diet. However, no information regarding Fasciola species contamination in water dropwort is available. Here, we collected 500 samples of water dropwort in 3 areas in Korea during February and March 2015, and the water dropwort contamination of Fasciola species was monitored by DNA sequencing analysis of the Fasciola hepatica and Fasciola gigantica specific mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear ribosomal internal transcribed spacer 2 (ITS-2). Among the 500 samples assessed, the presence of F. hepatica cox1 and 1TS-2 markers were detected in 2 samples, and F. hepatica contamination was confirmed by sequencing analysis. The nucleotide sequences of cox1 PCR products from the 2 F. hepatica-contaminated samples were 96.5% identical to the F. hepatica cox1 sequences in GenBank, whereas F. gigantica cox1 sequences were 46.8% similar with the sequence detected from the cox1 positive samples. However, F. gigantica cox1 and ITS-2 markers were not detected by PCR in the 500 samples of water dropwort. Collectively, in this survey of the water dropwort contamination with Fasciola species, very low prevalence of F. hepatica contamination was detected in the samples.

• IMMUNE NETWORK
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• v.6 no.4
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• pp.204-210
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• 2006

Background: Nitric oxide (NO) in articular chondrocytes regulates dedifferentiation and inflammatory responses by modulating MAP kinases. In this study, we investigated whether the Src kinase in chondrocytes regulates NO-induced dedifferentiation and cyclooxygenase-2 (COX-2) expression. Methods: Primary chondrocytes were treated with various concentrations of SNP for 24 h. The COX-2 and type II collagen expression levels were determined by immunoblot analysis, and prostaglandin $E_2\;(PGE_2)$ was determined by using a $PGE_2$ assay kit. Expression and distribution of p-Caveolin and COX-2 in rabbit articular chondrocytes and cartilage explants were determined by immunohistochemical staining and immunocytochemical staining, respectively. Results: SNP treatment stimulated Src kinase activation in a dose-dependent manner in articular chondrocytes. The Src kinase inhibitors PP2 [4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo(3,4-d)pyrimidine], a significantly blocked SNP-induced p38 kinase and caveolin-1 activation in a dose-dependent manner. Therefore, to determine whether Src kinase activation is associated with dedifferentiation and/or COX-2 expression and $PGE_2$ production. As expected, PP2 potentiated SNP-stimulated dedifferentiation, but completely blocked both COX-2 expression and $PGE_2$ production. And also, levels of p-Caveolin and COX-2 protein expression were increased in SNP-treated primary chondrocytes and osteoarthritic and rheumatoid arthritic cartilage, suggesting that p-Caveolin may playa role in the inflammatory responses of arthritic cartilage. Conclusion: Our previously studies indicated that NO caused dedifferentiation and COX-2 expression is regulated by p38 kinase through caveolin-1 (1). Therefore, our results collectively suggest that Src kinase regulates NO-induced dedifferentiation and COX-2 expression in chondrocytes via p38 kinase in association with caveolin-1.

• Biomolecules & Therapeutics
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• v.21 no.1
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• pp.54-59
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• 2013

In this study, we investigated the effect of (-)-epigallocatechin-3-gallate (EGCG), a major component of green tea catechins from green tea leaves, on activities of cyclooxygenase (COX)-1 and thromboxane synthase (TXAS), thromboxane $A_2$ ($TXA_2$) production associated microsomal enzymes. EGCG inhibited COX-1 activity to 96.9%, and TXAS activity to 20% in platelet microsomal fraction having cytochrome c reductase (an endoplasmic reticulum marker enzyme) activity and expressing COX-1 (70 kDa) and TXAS (58 kDa) proteins. The inhibitory ratio of COX-1 to TXAS by EGCG was 4.8. These results mean that EGCG has a stronger selectivity in COX-1 inhibition than TXAS inhibition. In special, a nonsteroid anti-inflammatory drug aspirin, a COX-1 inhibitor, inhibited COX-1 activity by 11.3% at the same concentration ($50{\mu}M$) as EGCG that inhibited COX-1 activity to 96.9% as compared with that of control. This suggests that EGCG has a stronger effect than that of aspirin on inhibition of COX-1 activity. Accordingly, we demonstrate that EGCG might be used as a crucial tool for a strong negative regulator of COX-1/$TXA_2$ signaling pathway to inhibit thrombotic disease-associated platelet aggregation.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.348-352
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• 2007

Inflammation is a complex process resulting from a variety of mechanisms. Combined inhibition of the activities of enzymes involved in the process may therefore be considered more important in anti-inflammatory property of plant extracts than any single contribution. In this study, the inhibitory effects of the ethanol extracts of thirty plant foods on the activities of secretory phospholipase $A_{2}$ ($sPLA_{2}$), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and 12-lipoxygenase (12-LOX) were examined. Several legumes, mungbean sprout and some leaf vegetables inhibited the activity of $sPLA_2$, upstream enzyme of inflammation pathway. Only soybean sprout and mungbean sprout significantly inhibited 12-LOX activity. Although most of extracts inhibited the activities of both COX-1 and COX-2, water dropwort and amaranth showed selectivity for the inhibition of COX-2 over COX-1. Especially, mungbean showed anti-inflammatory property at both upstream and downstream of inflammation pathway with relatively low $IC_{50}$ values for $sPLA_{2}$ and COX-2 enzymes. Mungbean sprout exhibited inhibitory effects on all enzymes related to early and late inflammation and soybean sprout suppressed 12-LOX and COX-2 simultaneously, although the activities of these plants were showed at relatively high concentration. Therefore, mungbean, mungbean sprout, and soybean sprout appear to exhibit anti-inflammatory effects by combined inhibition of inflammatory enzymes.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.1
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• pp.30-40
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• 2008

The objectives of this study was to check up the effect of celecoxib, COX-2 inhibitor, on the pathogenesis of oral squamous cell carcinoma. After mefenamic acid, aspirin and celecoxib, COX-2 inhibitor, were inoculated to HN 22 cell line, the following results were obtained through tumor cell viability by wortmannin, growth curve of tumor cell line, apoptotic index, PGE2 synthesis, total RNA extraction, RT-PCR analysis and TEM features. 1. When wortmannin and celecoxib were given together, the survival rate of tumor cells was lowest about 47 %. So wortmannin had an effect on the decrease of survival rate of tumor cells. 2. In growth curve, the slowest growth was observed in celecoxib inoculated group. 3. The synthesis of PGE2 was decreased in all group and the obvious suppression and highest apoptotic index was observed in celecoxib inoculated group. 4. Suppression of expression of COX-2 mRNA was evident in celecoxib inoculated group. But that of COX-1,2 mRNA was observed in mefenamic acid inoculated group and aspirin inoculated group. 5. In celecoxib inoculated group, mRNA expression of AKT1 was decreased and that of PTEN & expression of caspase 3 and 9 was evidently increased. Depending on above results, when celecoxib was inoculated to oral squamous cell carcinoma cell line, an increase of mRNA expression of caspase 3,9 and PTEN is related to a decrease of mRNA expression of AKT1. Wortmannin had an effect on the decrease of survival rate of tumor cells. Celecoxib might induce apoptosis of tumor cell by suppression of AKT1 pathway and COX-2 inhibition. This results suggested that COX-2 inhibitor might be significantly effective in chemoprevention of oral squamous cell carcinoma.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.20 no.1
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• pp.25-36
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• 1994

It is weal known that bacterial lipopolysaccharide (LPS) stimulates prostaglandin synthesis in various experimental system via enhancing the expression of cylooxygenase-2 (COX-2). This study was designed to characterize U)5-induced prostaglandin synthesis in mouse peritoneal macrophages LPS-stimulated prostaglandin synthesis in macrophages with short term exposure was not so much prominent, but there was a burst in prostaglandin synthesis 8 hours after the LPS treatment and this u·as accompanied with the increase of cyclooxygenase activity, Dexamethasone markedly inhibited prostaglandin synthesis in this system. Metabolic label ins data supported above observations and thus, it could be concluded that LPS induces the do novo synthesis of COX-2 by which it stimulates the prostaglandin synthesis in mouse peritoneal macrophages, These data suggested that this experimental model system could be used for the screening procedure of COX-2 selective inhibitors. Ketoprofen, a non steroidal anti inflammatory agent, appeared to inhibit COX-1 relatively more selectively than COX-2.

• Radiation Oncology Journal
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• v.25 no.3
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• pp.145-150
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• 2007

Purpose: To investigate the degree and effect of cyclooxygenase (COX)-2 expression on the survival of patients with glioblastoma multiforme (GM). Materials and Methods: Between 1997 and 2006, thirty consecutive GM patients treated with surgery and postoperative radiotherapy (dose range: $44{\sim}65.1$ Gy, median dose: 61.2 Gy) were included in the study. Three patients were excluded that discontinued radiotherapy before receiving a dose of 40 Gy due to mental deterioration. The expression of the COX-2 protein in surgical specimens was examined by immunohistochemical analysis. Survival analysis and verification were performed with respect to sex, age, performance status, resection extent, radiotherapy dose, and degree of COX-2 expression using the Kaplan-Meier method and the log rank test. Results: The median length of follow-up was 13.3 months (range:$6{\sim}83$ months). Staining for COX-2 was positive in all patient samples. Staining for COX-2 that was positive for over 75% of the tumor cells was found in 24 patients. Staining for COX-2 that was positive in less than 25% of tumor cells was found in 3 patients (10.0%), staining for COX-2 that was positive in 25 to 50% of tumor cells was found in 1 patient (3.3%), staining for COX-2 that was positive in 50 to 75% of tumor cells was found in 2 patients (6.7%) and staining for COX-2 that was positive in 75 to 100% of tumor cells was found in 24 patients (80.0%). The median survival and two-year survival rate were 13.5 months and 17.5%, respectively. The survival rate was influenced significantly by the degree of resection (tumor removal by 50% or more) and radiotherapy dose (59 Gy or greater) (p<0.05). The median survival of patients with staining for COX-2 that was positive in less than 75% of tumor cells and in at least 75% of tumor cells was 15.5 and 13.0 months, respectively (p>0.05), and the two-year survival for these groups was 33.3 and 13.3%, respectively (p>0.05). Conclusion: The absence of a statistical correlation between the degree of COX-2 expression and survival in GM patients, despite the high rate of COX-2 positive tumor cells in the GM patient samples, requires further studies with a larger series to ascertain the prognostic value of the degree of COX-2 expression in GM patients.

• Archives of Pharmacal Research
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• v.29 no.7
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• pp.548-555
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• 2006

Three diterpenes (1, 8, and 9), three triterpenes (3, 4, and 7), one saponin (11), four sterols (2, 5, 6, and 12), and one cerebroside (10) were isolated from the EtOH extract of the aerial parts of Aralia cordata by repeated silica gel column chromatography. Their chemical structures were identified by comparing their physicochemical and spectral data with those published in literatures. All isolated compounds were evaluated for their cytotoxicity against L1210, K562, and LLC tumor cell lines using MTT assay. Of which, $3{\beta},5{\alpha}-dihydroxy-6{\beta}-methoxyergosta-7,22-diene$ (6) showed a potent cytotoxicity against all cell lines with $IC_{50}$ values of 11.7, 11.9, and $15.1\;{\mu}M$, respectively, while compounds 1, 5, and 11 showed a moderate or weak cytotoxicity. These isolates were also examined for their inhibitory activity against COX-1 and COX-2. Although most compounds, except for 2, 10, and 12, showed a strong inhibitory activity against COX-1, they exhibited a moderate or weak inhibitory activity against COX-2.