Molecular basis of cyclooxygenase enzymes (COXs) selective inhibition

PubMed Central

Limongelli, Vittorio; Bonomi, Massimiliano; Marinelli, Luciana; Gervasio, Francesco Luigi; Cavalli, Andrea; Novellino, Ettore; Parrinello, Michele

2010-01-01

The widely used nonsteroidal anti-inflammatory drugs block the cyclooxygenase enzymes (COXs) and are clinically used for the treatment of inflammation, pain, and cancers. A selective inhibition of the different isoforms, particularly COX-2, is desirable, and consequently a deeper understanding of the molecular basis of selective inhibition is of great demand. Using an advanced computational technique we have simulated the full dissociation process of a highly potent and selective inhibitor, SC-558, in both COX-1 and COX-2. We have found a previously unreported alternative binding mode in COX-2 explaining the time-dependent inhibition exhibited by this class of inhibitors and consequently their long residence time inside this isoform. Our metadynamics-based approach allows us to illuminate the highly dynamical character of the ligand/protein recognition process, thus explaining a wealth of experimental data and paving the way to an innovative strategy for designing new COX inhibitors with tuned selectivity. PMID:20215464

Binding of indomethacin methyl ester to cyclooxygenase-2. A computational study.

PubMed

Sárosi, Menyhárt-Botond

2018-06-05

Inhibitors selective towards the second isoform of prostaglandin synthase (cyclooxygenase, COX-2) are promising nonsteroidal anti-inflammatory drugs and antitumor medications. Methylation of the carboxylate group in the relatively nonselective COX inhibitor indomethacin confers significant COX-2 selectivity. Several other modifications converting indomethacin into a COX-2 selective inhibitor have been reported. Earlier experimental and computational studies on neutral indomethacin derivatives suggest that the methyl ester derivative likely binds to COX-2 with a similar binding mode as that observed for the parent indomethacin. However, docking studies followed by molecular dynamics simulations revealed two possible binding modes in COX-2 for indomethacin methyl ester, which differs from the experimental binding mode found for indomethacin. Both alternative binding modes might explain the observed COX-2 selectivity of indomethacin methyl ester. Graphical abstract Binding of indomethacin methyl ester to cyclooxygenase-2.

Vitual screening and binding mode elucidation of curcumin analogues on Cyclooxygenase-2 using AYO_COX2_V1.1 protocol

NASA Astrophysics Data System (ADS)

Mulatsari, E.; Mumpuni, E.; Herfian, A.

2017-05-01

Curcumin is yellow colored phenolic compounds contained in Curcuma longa. Curcumin is known to have biological activities as anti-inflammatory, antiviral, antioxidant, and anti-infective agent [1]. Synthesis of curcumin analogue compounds has been done and some of them had biological activity like curcumin. In this research, the virtual screening of curcumin analogue compounds has been conducted. The purpose of this research was to determine the activity of these compounds as selective Cyclooxygenase-2inhibitors in in-silico. Binding mode elucidation was made by active and inactive representative compounds to see the interaction of the amino acids in the binding site of the compounds. This research used AYO_COX2_V.1.1, a structure-based virtual screening protocol (SBVS) that has been validated by Mumpuni E et al, 2014 [2]. AYO_COX2_V.1.1 protocol using a variety of integrated applications such as SPORES, PLANTS, BKchem, OpenBabel and PyMOL. The results of virtual screening conducted on 49 curcumin analogue compounds obtained 8 compounds with 4 active amino acid residues (GLY340, ILE503, PHE343, and PHE367) that were considered active as COX-2 inhibitor.

Cyclooxygenases in human and mouse skin and cultured human keratinocytes: association of COX-2 expression with human keratinocyte differentiation

NASA Technical Reports Server (NTRS)

Leong, J.; Hughes-Fulford, M.; Rakhlin, N.; Habib, A.; Maclouf, J.; Goldyne, M. E.

1996-01-01

Epidermal expression of the two isoforms of the prostaglandin H-generating cyclooxygenase (COX-1 and COX-2) was evaluated both by immunohistochemistry performed on human and mouse skin biopsy sections and by Western blotting of protein extracts from cultured human neonatal foreskin keratinocytes. In normal human skin, COX-1 immunostaining is observed throughout the epidermis whereas COX-2 immunostaining increases in the more differentiated, suprabasilar keratinocytes. Basal cell carcinomas express little if any COX-1 or COX-2 immunostaining whereas both isozymes are strongly expressed in squamous cell carcinomas deriving from a more differentiated layer of the epidermis. In human keratinocyte cultures, raising the extracellular calcium concentration, a recognized stimulus for keratinocyte differentiation, leads to an increased expression of both COX-2 protein and mRNA; expression of COX-1 protein, however, shows no significant alteration in response to calcium. Because of a recent report that failed to show COX-2 in normal mouse epidermis, we also looked for COX-1 and COX-2 immunostaining in sections of normal and acetone-treated mouse skin. In agreement with a previous report, some COX-1, but no COX-2, immunostaining is seen in normal murine epidermis. However, following acetone treatment, there is a marked increase in COX-1 expression as well as the appearance of significant COX-2 immunostaining in the basal layer. These data suggest that in human epidermis as well as in human keratinocyte cultures, the expression of COX-2 occurs as a part of normal keratinocyte differentiation whereas in murine epidermis, its constitutive expression is absent, but inducible as previously published.

Potential use of COX-2–aromatase inhibitor combinations in breast cancer

PubMed Central

Bundred, N J; Barnes, N L P

2005-01-01

Cyclooxygenase-2 (COX-2) is overexpressed in several epithelial tumours, including breast cancer. Cyclooxygenase-2-positive tumours tend to be larger, higher grade, node-positive and HER-2/neu-positive. High COX-2 expression is associated with poor prognosis. Cyclooxygenase-2 inhibition reduces the incidence of tumours in animal models, inhibits the development of invasive cancer in colorectal cancer and reduces the frequency of polyps in familial adenomatous polyposis (FAP). These effects may be as a result of increased apoptosis, reduced angiogenesis and/or proliferation. Studies of COX-2 inhibitors in breast cancer are underway both alone and in combination with other agents. There is evidence to suggest that combining COX-2 inhibitors with aromatase inhibitors, growth factor receptor blockers, or chemo- or radiotherapy may be particularly effective. Preliminary results from combination therapy with celecoxib and exemestane in postmenopausal women with advanced breast cancer showed that the combination increased the time to recurrence. Up to 80% of ductal carcinomas in situ (DCISs) express COX-2, therefore COX-2 inhibition may be of particular use in this situation. Cyclooxygenase-2 expression correlates strongly with expression of HER-2/neu. As aromatase inhibitors appear particularly effective in patients with HER-2/neu-positive tumours, the combination of aromatase inhibitors and COX-2 inhibitors may be particularly useful in both DCIS and invasive cancer. PMID:16100520

Corn silk induced cyclooxygenase-2 in murine macrophages.

PubMed

Kim, Kyung A; Shin, Hyun-Hee; Choi, Sang Kyu; Choi, Hye-Seon

2005-10-01

Stimulation of murine macrophages with corn silk induced cyclooxygenase (COX)-2 with secretion of PGE2. Expression of COX-2 was inhibited by pyrolidine dithiocarbamate (PDTC), and increased DNA binding by nuclear factor kappa B (NF-kappaB), indicating that COX-2 induction proceeds also via the NF-kappaB signaling pathway. A specific inhibitor of COX-2 decreased the expression level of inducible nitric oxide synthase (iNOS) stimulated by corn silk. PGE2 elevated the expression level of iNOS, probably via EP2 and EP4 receptors on the surface of the macrophages.

Sulforaphane suppresses lipopolysaccharide-induced cyclooxygenase-2 (COX-2) expression through the modulation of multiple targets in COX-2 gene promoter.

PubMed

Woo, Kyung Jin; Kwon, Taeg Kyu

2007-12-15

Sulforaphane is a natural, biologically active compound extracted from cruciferous vegetables such as broccoli and cabbage. It possesses potent anti-inflammation and anti-cancer properties. The mechanism by which sulforaphane suppresses COX-2 expression remains poorly understood. In the present report, we investigated the effect of sulforaphane on the expression of COX-2 in lipopolysaccharide (LPS)-activated Raw 264.7 cells. Sulforaphane significantly suppressed the LPS-induced COX-2 protein and mRNA expression in a dose-dependent manner. The ability of sulforaphane to suppress the expression of the COX-2 was investigated using luciferase reporters controlled by various cis-elements in COX-2 promoter region. Electrophoretic mobility shift assay (EMSA) verified that NF-kappaB, C/EBP, CREB and AP-1 were identified as responsible for the sulforaphane-mediated COX-2 down-regulation. In addition, we demonstrated the signal transduction pathway of mitogen-activated protein kinase (MAP kinase) in LPS-induced COX-2 expression. Taken together, these results demonstrate that sulforaphane effectively suppressed the LPS-induced COX-2 protein via modulation of multiple core promoter elements (NF-kappaB, C/EBP, CREB and AP-1) in the COX-2 transcriptional regulation. These results will provide new insights into the anti-inflammatory and anti-carcinogenic properties of sulforaphane.

Up-regulation of cyclooxygenase-2 by product-prostaglandin E2

NASA Technical Reports Server (NTRS)

Tjandrawinata, R. R.; Hughes-Fulford, M.

1997-01-01

The development of prostate cancer has been linked to high level of dietary fat intake. Our laboratory investigates the connection between cancer cell growth and fatty acid products. Studying human prostatic carcinoma PC-3 cells, we found that prostaglandin E2 (PGE2) increased cell growth and up-regulated the gene expression of its own synthesizing enzyme, cyclooxygenase-2 (COX-2). PGE2 increased COX-2 mRNA expression dose-dependently with the highest levels of stimulation seen at the 3-hour period following PGE2 addition. The NSAID flurbiprofen (5 microM), in the presence of exogenous PGE2, inhibited the up-regulation of COX-2 mRNA and cell growth. These data suggest that the levels of local intracellular PGE2 play a major role in the growth of prostate cancer cells through an activation of COX-2 gene expression.

Cyclooxygenase-2 is an obligatory factor in methamphetamine-induced neurotoxicity.

PubMed

Thomas, David M; Kuhn, Donald M

2005-05-01

Methamphetamine causes persistent damage to dopamine nerve endings of the striatum. The mechanisms underlying its neurotoxicity are not fully understood, but considerable evidence points to oxidative stress as a probable mechanism. A recent microarray analysis of gene expression changes caused by methamphetamine revealed that cyclooxygenase-2 (COX-2) was induced along with its transcription factor CCAAT/enhancer-binding protein (Thomas DM, Francescutti-Verbeem DM, Liu X, and Kuhn DM, 2004). We report presently that methamphetamine increases striatal expression of COX-2 protein. Cyclooxygenase-1 (COX-1) expression was not changed. Mice bearing a null mutation of the gene for COX-2 were resistant to methamphetamine-induced neurotoxicity. COX-1 knockouts, like wild-type mice, showed extensive dopamine nerve terminal damage. Selective inhibitors of COX-1 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethyl pyrazole (SC-560)], COX-2 [N-[2-(cyclohexyloxy)-4-nitrophenyl] methanesulfonamide (NS-398), rofecoxib], or COX-3 (antipyrine) or a nonselective inhibitor of the COX-1/2 isoforms (ketoprofen) did not protect mice from neurotoxicity. Finally, methamphetamine did not change striatal prostaglandin E(2) content. Taken together, these data suggest that COX-2 is an obligatory factor in methamphetamine-induced neurotoxicity. The functional aspect of COX-2 that contributes to drug-induced neurotoxicity does not appear to be its prostaglandin synthetic capacity. Instead, the peroxidase activity associated with COX-2, which can lead to the formation of reactive oxygen species and dopamine quinones, can account for its role.

Design, Synthesis, and Evaluation of New Tripeptides as COX-2 Inhibitors.

PubMed

Vernieri, Ermelinda; Gomez-Monterrey, Isabel; Milite, Ciro; Grieco, Paolo; Musella, Simona; Bertamino, Alessia; Scognamiglio, Ilaria; Alcaro, Stefano; Artese, Anna; Ortuso, Francesco; Novellino, Ettore; Sala, Marina; Campiglia, Pietro

2013-01-01

Cyclooxygenase (COX) is a key enzyme in the biosynthetic pathway leading to the formation of prostaglandins, which are mediators of inflammation. It exists mainly in two isoforms COX-1 and COX-2. The conventional nonsteroidal anti-inflammatory drugs (NSAIDs) have gastrointestinal side effects because they inhibit both isoforms. Recent data demonstrate that the overexpression of these enzymes, and in particular of cyclooxygenases-2, promotes multiple events involved in tumorigenesis; in addition, numerous studies show that the inhibition of cyclooxygenases-2 can delay or prevent certain forms of cancer. Agents that inhibit COX-2 while sparing COX-1 represent a new attractive therapeutic development and offer a new perspective for a further use of COX-2 inhibitors. The present study extends the evaluation of the COX activity to all 20(3) possible natural tripeptide sequences following a rational approach consisting in molecular modeling, synthesis, and biological tests. Based on data obtained from virtual screening, only those peptides with better profile of affinity have been selected and classified into two groups called S and E. Our results suggest that these novel compounds may have potential as structural templates for the design and subsequent development of the new selective COX-2 inhibitors drugs.

Crystal structure of rofecoxib bound to human cyclooxygenase-2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orlando, Benjamin J.; Malkowski, Michael G.

2016-10-26

Rofecoxib (Vioxx) was one of the first selective cyclooxygenase-2 (COX-2) inhibitors (coxibs) to be approved for use in humans. Within five years after its release to the public, Vioxx was withdrawn from the market owing to the adverse cardiovascular effects of the drug. Despite the widespread knowledge of the development and withdrawal of Vioxx, relatively little is known at the molecular level about how the inhibitor binds to COX-2. Vioxx is unique in that the inhibitor contains a methyl sulfone moiety in place of the sulfonamide moiety found in other coxibs such as celecoxib and valdecoxib. Here, new crystallization conditionsmore » were identified that allowed the structural determination of human COX-2 in complex with Vioxx and the structure was subsequently determined to 2.7- Å resolution. The crystal structure provides the first atomic level details of the binding of Vioxx to COX-2. As anticipated, Vioxx binds with its methyl sulfone moiety located in the side pocket of the cyclooxygenase channel, providing support for the isoform selectivity of this drug.« less

Cyclooxygenase-2 inhibitors in ginger (Zingiber officinale)

PubMed Central

van Breemen, Richard B.; Tao, Yi; Li, Wenkui

2010-01-01

Ginger roots have been used to treat inflammation and have been reported to inhibit cyclooxygenase (COX). Ultrafiltration liquid chromatography mass spectrometry was used to screen a chloroform partition of a methanol extract of ginger roots for COX-2 ligands, and 10-gingerol, 12-gingerol, 8-shogaol, 10-shogaol, 6-gingerdione, 8-gingerdione, 10-gingerdione, 6-dehydro-10-gingerol, 6-paradol, and 8-paradol bound to the enzyme active site. Purified 10-gingerol, 8-shogaol and 10-shogaol inhibited COX-2 with IC50 values of 32 μM, 17.5 μM and 7.5 μM, respectively. No inhibition of COX-1 was detected. Therefore, 10-gingerol, 8-shogaol and 10-shogaol inhibit COX-2 but not COX-1, which can explain, in part, anti-inflammatory properties of ginger. PMID:20837112

New Ferrocene Compounds as Selective Cyclooxygenase (COX-2) Inhibitors: Design, Synthesis, Cytotoxicity and Enzyme-inhibitory Activity.

PubMed

Farzaneh, Shabnam; Zeinalzadeh, Elnaz; Daraei, Bahram; Shahhosseini, Soraya; Zarghi, Afshin

2018-01-01

Due to the astonishing properties of ferrocene and its derivatives, it has a broad application in diverse areas. Numerous ferrocene derivatives demonstrated anti-proliferative activity. Also COX-2, as a key isoenzyme for production of prostaglandins, is frequently overexpressed in various cancers. It is now recognized that COX-2 over expression promotes tumorigenic functions which can be suppressed by COX-2 inhibitors, a phenomenon useful for the preventing of tumor progression. The combination of COX-2 inhibitors with other anti-cancer or cancer prevention drugs may reduce their side effects in future cancer prevention and treatment. Owing to high anticancer potential of ferrocene derivatives and considerable COX-2 inhibitory and cytotoxicity effects of our previously synthesized chalcones, we decided to incorporate the ferrocenyl moiety into appropriate COX-2 inhibitor chalcone based scaffold, to evaluate COX-2 inhibitory activity as well as anticancer activities. Chalcones were synthesized via clasien-schmidt condensation of methylsulfonyl aldehyde and acetyl ferrocene. Further different amines with solvent free and ultra sound condition were reacted with chalcones to have different 1-ferrocenyl-3-amino carbonyl compounds. Docking study was carried out with Auto Dock vina software. All the newly-synthesized compounds were evaluated for their cyclooxygenase-2 (COX-2) inhibitory activity using chemiluminescent enzyme assays as well as cytotoxicity activity against MCF-7 and T47D and fibroblast cell lines by MTT assay. In vitro COX-1/COX-2 inhibition studies demonstrated that all compounds were selective inhibitors of the COX-2 isozyme with IC50 values in the highly potent 0.05-0.12 µM range, and COX-2 selectivity indexes (SI) in the 148.3-313.7 range. These results indicated that either potency or selectivity of COX-2 inhibitory activity was affected by the nature and size of the substituents on C-3 of propane-1-one. Also anti-proliferative and toxicity

Cyclooxygenase-2 inhibitory and antioxidant compounds from the truffle Elaphomyces granulatus

Treesearch

Rita Stanikunaite; Shabana I. Khan; James M. Trappe; Samir A. Ross

2009-01-01

The ethanol extract of fruiting bodies of Elaphomyces granulatus, a truffle-like fungus, was evaluated for cyclooxygenase-2 (COX-2) enzyme inhibitory and antioxidant activities. Inhibition of COX-2 activity was evaluated in mouse macrophages (RAW 264.7). The extract of E. granulatus caused a 68% inhibition of COX-2 activity at...

Cyclooxygenase 2 Promotes Parathyroid Hyperplasia in ESRD

PubMed Central

Zhang, Qian; Qiu, Junsi; Li, Haiming; Lu, Yanwen; Wang, Xiaoyun; Yang, Junwei; Wang, Shaoqing; Zhang, Liyin; Gu, Yong; Hao, Chuan-Ming

2011-01-01

Hyperplasia of the PTG underlies the secondary hyperparathyroidism (SHPT) observed in CKD, but the mechanism underlying this hyperplasia is incompletely understood. Because aberrant cyclooxygenase 2 (COX2) expression promotes epithelial cell proliferation, we examined the effects of COX2 on the parathyroid gland in uremia. In patients with ESRD who underwent parathyroidectomy, clusters of cells within the parathyroid glands had increased COX2 expression. Some COX2-positive cells exhibited two nuclei, consistent with proliferation. Furthermore, nearly 78% of COX2-positive cells expressed proliferating cell nuclear antigen (PCNA). In the 5/6-nephrectomy rat model, rats fed a high-phosphate diet had significantly higher serum PTH levels and larger parathyroid glands than sham-operated rats. Compared with controls, the parathyroid glands of uremic rats exhibited more PCNA-positive cells and greater COX2 expression in the chief cells. Treatment with COX2 inhibitor celecoxib significantly reduced PCNA expression, attenuated serum PTH levels, and reduced the size of the glands. In conclusion, COX2 promotes the pathogenesis of hyperparathyroidism in ESRD, suggesting that inhibiting the COX2 pathway could be a potential therapeutic target. PMID:21335517

COX2 Inhibition Reduces Aortic Valve Calcification In Vivo

PubMed Central

Wirrig, Elaine E.; Gomez, M. Victoria; Hinton, Robert B.; Yutzey, Katherine E.

2016-01-01

Objective Calcific aortic valve disease (CAVD) is a significant cause of morbidity and mortality, which affects approximately 1% of the US population and is characterized by calcific nodule formation and stenosis of the valve. Klotho-deficient mice were used to study the molecular mechanisms of CAVD as they develop robust aortic valve (AoV) calcification. Through microarray analysis of AoV tissues from klotho-deficient and wild type mice, increased expression of the gene encoding cyclooxygenase 2/COX2 (Ptgs2) was found. COX2 activity contributes to bone differentiation and homeostasis, thus the contribution of COX2 activity to AoV calcification was assessed. Approach and Results In klotho-deficient mice, COX2 expression is increased throughout regions of valve calcification and is induced in the valvular interstitial cells (VICs) prior to calcification formation. Similarly, COX2 expression is increased in human diseased AoVs. Treatment of cultured porcine aortic VICs with osteogenic media induces bone marker gene expression and calcification in vitro, which is blocked by inhibition of COX2 activity. In vivo, genetic loss of function of COX2 cyclooxygenase activity partially rescues AoV calcification in klotho-deficient mice. Moreover, pharmacologic inhibition of COX2 activity in klotho-deficient mice via celecoxib-containing diet reduces AoV calcification and blocks osteogenic gene expression. Conclusions COX2 expression is upregulated in CAVD and its activity contributes to osteogenic gene induction and valve calcification in vitro and in vivo. PMID:25722432

Opposing Effects of Cyclooxygenase-2 (COX-2) on Estrogen Receptor β (ERβ) Response to 5α-Reductase Inhibition in Prostate Epithelial Cells*

PubMed Central

Liu, Teresa T.; Grubisha, Melanie J.; Frahm, Krystle A.; Wendell, Stacy G.; Liu, Jiayan; Ricke, William A.; Auchus, Richard J.; DeFranco, Donald B.

2016-01-01

Current pharmacotherapies for symptomatic benign prostatic hyperplasia (BPH), an androgen receptor-driven, inflammatory disorder affecting elderly men, include 5α-reductase (5AR) inhibitors (i.e. dutasteride and finasteride) to block the conversion of testosterone to the more potent androgen receptor ligand dihydrotestosterone. Because dihydrotestosterone is the precursor for estrogen receptor β (ERβ) ligands, 5AR inhibitors could potentially limit ERβ activation, which maintains prostate tissue homeostasis. We have uncovered signaling pathways in BPH-derived prostate epithelial cells (BPH-1) that are impacted by 5AR inhibition. The induction of apoptosis and repression of the cell adhesion protein E-cadherin by the 5AR inhibitor dutasteride requires both ERβ and TGFβ. Dutasteride also induces cyclooxygenase type 2 (COX-2), which functions in a negative feedback loop in TGFβ and ERβ signaling pathways as evidenced by the potentiation of apoptosis induced by dutasteride or finasteride upon pharmacological inhibition or shRNA-mediated ablation of COX-2. Concurrently, COX-2 positively impacts ERβ action through its effect on the expression of a number of steroidogenic enzymes in the ERβ ligand metabolic pathway. Therefore, effective combination pharmacotherapies, which have included non-steroidal anti-inflammatory drugs, must take into account biochemical pathways affected by 5AR inhibition and opposing effects of COX-2 on the tissue-protective action of ERβ. PMID:27226548

Select Dietary Phytochemicals Function as Inhibitors of COX-1 but Not COX-2

PubMed Central

Li, Haitao; Zhu, Feng; Sun, Yanwen; Li, Bing; Oi, Naomi; Chen, Hanyong; Lubet, Ronald A.; Bode, Ann M.; Dong, Zigang

2013-01-01

Recent clinical trials raised concerns regarding the cardiovascular toxicity of selective cyclooxygenase-2 (COX-2) inhibitors. Many active dietary factors are reported to suppress carcinogenesis by targeting COX-2. A major question was accordingly raised: why has the lifelong use of phytochemicals that likely inhibit COX-2 presumably not been associated with adverse cardiovascular side effects. To answer this question, we selected a library of dietary-derived phytochemicals and evaluated their potential cardiovascular toxicity in human umbilical vein endothelial cells. Our data indicated that the possibility of cardiovascular toxicity of these dietary phytochemicals was low. Further mechanistic studies revealed that the actions of these phytochemicals were similar to aspirin in that they mainly inhibited COX-1 rather than COX-2, especially at low doses. PMID:24098505

Crystallization of recombinant cyclo-oxygenase-2

NASA Astrophysics Data System (ADS)

Stevens, Anna M.; Pawlitz, Jennifer L.; Kurumbail, Ravi G.; Gierse, James K.; Moreland, Kirby T.; Stegeman, Roderick A.; Loduca, Jina Y.; Stallings, William C.

1999-01-01

The integral membrane protein, prostaglandin H 2 synthase, or cyclo-oxygenase (COX), catalyses the first step in the conversion of arachidonic acid to prostaglandins (PGs) and is the target of nonsteroidal anti-inflammatory drugs (NSAIDs). Two isoforms are known. The constitutive enzyme, COX-1, is present in most tissues and is responsible for the physiological production of PGs. The isoform responsible for the elevated production of PGs during inflammation is COX-2 which is induced specifically at inflammatory sites. Three-dimensional structures of inhibitor complexes of COX-2, and of site variants of COX-2 which mimic COX-1, provide insight into the structural basis for selective inhibition of COX-2. Additionally, structures of COX-2 mutants and complexes with the substrate can provide a clearer understanding of the catalytic mechanism of the reaction. A crystallization protocol has been developed for COX-2 which reproducibly yields diffraction quality crystals. Polyethyleneglycol 550 monomethylether (MMP550) and MgCl 2 were systematically varied and used in conjunction with the detergent β- D-octylglucopyranoside ( β-OG). As a result of many crystallization trials, we determined that the initial β-OG concentration should be held constant, allowing the salt concentration to modulate the critical micelle concentration (CMC) of the detergent. Over 25 crystal structures have been solved using crystals generated from this system. Most crystals belong to the space group P2 12 12, with lattice constants of a=180, b=134, c=120 Å in a pseudo body-centered lattice.

Effects of the estrous cycle, pregnancy and interferon tau on expression of cyclooxygenase two (COX-2) in ovine endometrium

PubMed Central

Kim, Seokwoon; Choi, Youngsok; Spencer, Thomas E; Bazer, Fuller W

2003-01-01

In sheep, the uterus produces luteolytic pulses of prostaglandin F2α (PGF) on Days 15 to 16 of estrous cycle to regress the corpus luteum (CL). These PGF pulses are produced by the endometrial lumenal epithelium (LE) and superficial ductal glandular epithelium (sGE) in response to binding of pituitary and/or luteal oxytocin to oxytocin receptors (OTR) and liberation of arachidonic acid, the precursor of PGF. Cyclooxygenase-one (COX-1) and COX-2 are rate-limiting enzymes in PGF synthesis, and COX-2 is the major form expressed in ovine endometrium. During pregnancy recognition, interferon tau (IFNτ), produced by the conceptus trophectoderm, acts in a paracrine manner to suppress development of the endometrial epithelial luteolytic mechanism by inhibiting transcription of estrogen receptor α (ERα) (directly) and OTR (indirectly) genes. Conflicting studies indicate that IFNτ increases, decreases or has no effect on COX-2 expression in bovine and ovine endometrial cells. In Study One, COX-2 mRNA and protein were detected solely in endometrial LE and sGE of both cyclic and pregnant ewes. During the estrous cycle, COX-2 expression increased from Days 10 to 12 and then decreased to Day 16. During early pregnancy, COX-2 expression increased from Days 10 to 12 and remained higher than in cyclic ewes. In Study Two, intrauterine infusion of recombinant ovine IFNτ in cyclic ewes from Days 11 to 16 post-estrus did not affect COX-2 expression in the endometrial epithelium. These results clearly indicate that IFNτ has no effect on expression of the COX-2 gene in the ovine endometrium. Therefore, antiluteolytic effects of IFNτ are to inhibit ERα and OTR gene transcription, thereby preventing endometrial production of luteolytic pulses of PGF. Indeed, expression of COX-2 in the endometrial epithelia as well as conceptus is likely to have a beneficial regulatory role in implantation and development of the conceptus. PMID:12956885

Inhibition of cyclooxygenase-2 (COX-2) by meloxicam decreases the incidence of ovarian hyperstimulation syndrome in a rat model.

PubMed

Quintana, Ramiro; Kopcow, Laura; Marconi, Guillermo; Young, Edgardo; Yovanovich, Carola; Paz, Dante A

2008-10-01

To investigate the effects of selective cyclooxygenase-2 (COX-2) inhibition on the ovarian hyperstimulation syndrome (OHSS) in an experimental model. Controlled laboratory study. University-affiliated fertility center. Female Wistar rats. Female Wistar rats (22 days old) were divided into four groups: group 1 (control group; n = 10) received 0.1 mL of intraperitoneal (IP) saline from days 22-26; group 2 (mild-stimulated group; n = 10) received 10 IU of pregnant mare serum gonadotropin (PMSG) on day 24 and 10 IU of hCG 48 hours later (day 26); group 3 (OHSS group; n = 10) was given 10 IU of PMSG for 4 consecutive days from day 22 and 30 IU hCG on the fifth day to induce OHSS; group 4 was treated the same as group 3, but received 2 muL (15 mg/mL) of meloxicam 2 hours before the PMSG injection for 4 consecutive days, and 2 hours before the hCG injection on the fifth day. All groups were killed on day 26. Number of antral and luteinized follicles, ovarian weight, semiquantitative vascular endothelial growth factor (VEGF) and COX-2 immunohistochemistry. There were no differences in the ovarian weight between groups 1 and 2. Group 3 showed significantly increased ovarian weight that was suppressed, in group 4, by meloxicam. There was no difference in the number of antral follicles among the four groups. In the mild-stimulated and OHSS groups, the granulosa cells (GC) of preovulatory follicles and the stromal cells showed intense VEGF immunoreactivity. The ovaries from the meloxicam-treated group showed less immunoreactivity than the OHSS group, indicating diminished VEGF expression associated with meloxicam treatment. Group 3 (OHSS group) showed increased COX-2 immunoreactivity that was diminished in the meloxicam-treated group. Meloxicam treatment did not affect the hormone-induced increase in serum E(2) levels seen in OHSS rats. Our results in a rat model suggest that meloxicam has a beneficial effect on OHSS by reducing the increases in ovarian weight and VEGF

Targeted Deletions of COX-2 and Atherogenesis in Mice

PubMed Central

Hui, Yiqun; Ricciotti, Emanuela; Crichton, Irene; Yu, Zhou; Wang, Dairong; Stubbe, Jane; Wang, Miao; Puré, Ellen; FitzGerald, Garret A.

2010-01-01

Background While the dominant product of vascular cyclooxygenase (COX)-2, prostacyclin (PGI2), restrains atherogenesis, inhibition and deletion of COX-2 have yielded conflicting results in mouse models of atherosclerosis. Floxed mice were used to parse distinct cellular contributions of COX-2 in macrophages (Mac) and T cells (TC) to atherogenesis. Methods and Results Deletion of Mac COX-2 (MacKO) was attained using LysMCre mice and suppressed completely lipopolysaccharide (LPS) stimulated Mac prostaglandin (PG) formation and LPS evoked systemic PG biosynthesis by ∼ 30%. LPS stimulated COX-2 expression was suppressed in polymorphonuclear leucocytes (PMN) isolated from MacKOs, but PG formation was not even detected in PMN supernatants from control mice. Atherogenesis was attenuated when MacKOs were crossed into hyperlipidemic LdlR KOs. Deletion of Mac COX-2 appeared to remove a restraint on COX-2 expression in lesional non-leukocyte (CD45 and CD11b negative) vascular cells that express vascular cell adhesion molecule and variably, α-smooth muscle actin and vimentin, portending a shift in PG profile and consequent atheroprotection. Basal expression of COX-2 was minimal in TCs, but use of CD4Cre to generate TC knockouts (TCKOs) depressed its modest upregulation by anti-CD3ε. However, biosynthesis of PGs, TC composition in lymphatic organs and atherogenesis in LDLR KOs were unaltered in TCKOs. Conclusions Mac COX-2, primarily a source of thromboxane A2 and PGE2, promotes atherogenesis and exerts a restraint on enzyme expression by lesional cells suggestive of vascular smooth muscle cells, a prominent source of atheroprotective PGI2. TC COX-2 does not influence detectably TC development or function nor atherogenesis in mice. PMID:20530000

Cyclooxygenase-2 polymorphisms in Parkinson's disease.

PubMed

Håkansson, Anna; Bergman, Olle; Chrapkowska, Cecilia; Westberg, Lars; Belin, Andrea Carmine; Sydow, Olof; Johnels, Bo; Olson, Lars; Holmberg, Björn; Nissbrandt, Hans

2007-04-05

Accumulating evidence indicate that cyclooxygenase-2 (COX-2) is of pathophysiological importance for the neurodegeneration in Parkinson's disease (PD). For example, in a large epidemiological study, use of NSAIDs was associated with a lower risk of PD. Genetic variants of the COX-2 gene might therefore influence the risk of developing the disease. The genotype distribution of four common single nucleotide polymorphisms (SNPs) in the COX-2 gene (rs689466:A496G, rs20417:G926C, rs5277:G3050C, rs5275:C8473T) was analyzed in PD patients and control subjects in a Swedish population. No differences could be seen between the PD-patient and controls regarding the A496G, G926C, and G3050C SNPs, but the allele frequency of the C8473T SNP was found to differ when male patients were compared to controls (P = 0.007). In females no difference could be seen between PD-patients and controls. In conclusion, the results suggest a possible influence of the COX-2 C8473T SNP in PD, although it only seems to be of importance in men. (c) 2006 Wiley-Liss, Inc.

Immunosensors for quantifying cyclooxygenase 2 pain biomarkers.

PubMed

Noah, Naumih M; Mwilu, Samuel K; Sadik, Omowunmi A; Fatah, Alim A; Arcilesi, Richard D

2011-07-15

Cyclooxygenase 2 (COX-2) is a key enzyme in pain biomarkers, inflammation and cancer cell proliferation. Thus biosensors that can quantify pain mediators based on biochemical mechanism are imperative. Biomolecular recognition and affinity of antigenic COX-2 with the antibody were investigated using surface plasmon resonance (SPR) and ultra-sensitive portable capillary (UPAC) fluorescence sensors. Polyclonal goat anti-COX-2 (human) antibodies were covalently immobilized on gold SPR surface and direct recognition for the COX-2 antigen assessed. The UPAC sensor utilized an indirect sandwich design involving covalently attached goat anti-COX-2 as the capture antibody and rabbit anti-COX-2 (human) antibody as the secondary antibody. UPAC fluorescence signals were directly proportional to COX-2 at a linear range of 7.46×10⁻⁴-7.46×10¹ ng/ml with detection limit of 1.02×10⁻⁴ ng/ml. With SPR a linear range was 3.64×10⁻⁴-3.64×10² ng/ml was recorded and a detection limit of 1.35×10⁻⁴ ng/ml. Validation was achieved in simulated blood samples with percent recoveries of 81.39% and 87.23% for SPR and UPAC respectively. The developed sensors have the potential to provide objective characterization of pain biomarkers for clinical diagnoses. Copyright © 2011 Elsevier B.V. All rights reserved.

Tpl-2/Cot and COX-2 in breast cancer.

PubMed

Krcova, Zuzana; Ehrmann, Jiri; Krejci, Veronika; Eliopoulos, Aris; Kolar, Zdenek

2008-06-01

Breast cancer is the most common cancer in women worldwide and although mortality (129,000/year) stagnates, incidence (370,000/year) is increasing. In addition to histological type, grade, stage, hormonal and c-erbB2 status there is therefore a strong need for new and reliable prognostic and predictive factors. This minireview focuses on two potential prognostic and predictive candidates Tpl2/Cot and COX-2 and summarise information about them. Tumor progression locus 2 (Tpl2/Cot) is a serine/threonine protein kinase belonging to the family of MAP3 kinases. Activated Tpl2/Cot leads to induction of ERK1/2, JNK, NF-kappaB and p38MAPK pathways. The first study on Tpl2/Cot mRNA in breast cancer showed its increase in 40 % of cases of breast cancer but no available data exist on protein expression. Cyclo-oxygenase 2 (COX-2) is inducible by growth and inflammatory factors and contributes to the development of various tumours. Expression of COX-2 in breast cancer varied from 5-100 % in reviewed papers with significantly higher values in poorly differentiated tumours. Tpl2/Cot and COX-2 have their importance in different intracellular pathways and some of these are involved in cancer development. Briefly, the results from recent studies suggest that Tpl2/Cot and COX-2 could be prognostic factors in breast cancer.

Cyclooxygenase-1, not cyclooxygenase-2, is responsible for physiological production of prostacyclin in the cardiovascular system

PubMed Central

Kirkby, Nicholas S.; Lundberg, Martina H.; Harrington, Louise S.; Leadbeater, Philip D. M.; Milne, Ginger L.; Potter, Claire M. F.; Al-Yamani, Malak; Adeyemi, Oladipupo; Warner, Timothy D.; Mitchell, Jane A.

2012-01-01

Prostacyclin is an antithrombotic hormone produced by the endothelium, whose production is dependent on cyclooxygenase (COX) enzymes of which two isoforms exist. It is widely believed that COX-2 drives prostacyclin production and that this explains the cardiovascular toxicity associated with COX-2 inhibition, yet the evidence for this relies on indirect evidence from urinary metabolites. Here we have used a range of experimental approaches to explore which isoform drives the production of prostacyclin in vitro and in vivo. Our data show unequivocally that under physiological conditions it is COX-1 and not COX-2 that drives prostacyclin production in the cardiovascular system, and that urinary metabolites do not reflect prostacyclin production in the systemic circulation. With the idea that COX-2 in endothelium drives prostacyclin production in healthy individuals removed, we must seek new answers to why COX-2 inhibitors increase the risk of cardiovascular events to move forward with drug discovery and to enable more informed prescribing advice. PMID:23045674

Synthesis and pharmacological evaluation of N-substituted 2-(2-oxo-2H-chromen-4-yloxy)propanamide as cyclooxygenase inhibitors.

PubMed

Rambabu, D; Mulakayala, Naveen; Ismail; Kumar, K Ravi; Kumar, G Pavan; Mulakayala, Chaitanya; Kumar, Chitta Suresh; Kalle, Arunasree M; Rao, M V Basaveswara; Oruganti, Srinivas; Pal, Manojit

2012-11-01

A series of novel N-substituted 2-(2-oxo-2H-chromen-4-yloxy)propanamide derivatives were synthesized via converting the readily available 4-hydroxy coumarin to the corresponding ethyl 2-(2-oxo-2H-chromen-4-yloxy)propanoate followed by hydrolysis and then reacting with different substituted amines. The molecular structures of two representative compounds, that is, 3 and 5l were confirmed by single crystal X-ray diffraction study. All the compounds synthesized were evaluated for their cyclooxygenase (COX) inhibiting properties in vitro. The compound 5i showed balanced selectivity towards COX-2 over COX-1 inhibition and good docking scores when docked into the COX-2 protein. Copyright © 2012 Elsevier Ltd. All rights reserved.

Norepinephrine enhances the LPS-induced expression of COX-2 and secretion of PGE2 in primary rat microglia

PubMed Central

2010-01-01

Background Recent studies suggest an important role for neurotransmitters as modulators of inflammation. Neuroinflammatory mediators such as cytokines and molecules of the arachidonic acid pathway are generated and released by microglia. The monoamine norepinephrine reduces the production of cytokines by activated microglia in vitro. However, little is known about the effects of norepinephrine on prostanoid synthesis. In the present study, we investigate the role of norepinephrine on cyclooxygenase- (COX-)2 expression/synthesis and prostaglandin (PG)E2 production in rat primary microglia. Results Interestingly, norepinephrine increased COX-2 mRNA, but not protein expression. Norepinephrine strongly enhanced COX-2 expression and PGE2 production induced by lipopolysaccharide (LPS). This effect is likely to be mediated by β-adrenoreceptors, since β-, but not α-adrenoreceptor agonists produced similar results. Furthermore, β-adrenoreceptor antagonists blocked the enhancement of COX-2 levels induced by norepinephrine and β-adrenoreceptor agonists. Conclusions Considering that PGE2 displays different roles in neuroinflammatory and neurodegenerative disorders, norepinephrine may play an important function in the modulation of these processes in pathophysiological conditions. PMID:20064241

Binding Energy Calculation of Patchouli Alcohol Isomer Cyclooxygenase Complexes Suggested as COX-1/COX-2 Selective Inhibitor

PubMed Central

Mahdi, Chanif; Nurdiana, Nurdiana; Kikuchi, Takheshi; Fatchiyah, Fatchiyah

2014-01-01

To understand the structural features that dictate the selectivity of the two isoforms of the prostaglandin H2 synthase (PGHS/COX), the three-dimensional (3D) structure of COX-1/COX-2 was assessed by means of binding energy calculation of virtual molecular dynamic with using ligand alpha-Patchouli alcohol isomers. Molecular interaction studies with COX-1 and COX-2 were done using the molecular docking tools by Hex 8.0. Interactions were further visualized by using Discovery Studio Client 3.5 software tool. The binding energy of molecular interaction was calculated by AMBER12 and Virtual Molecular Dynamic 1.9.1 software. The analysis of the alpha-Patchouli alcohol isomer compounds showed that all alpha-Patchouli alcohol isomers were suggested as inhibitor of COX-1 and COX-2. Collectively, the scoring binding energy calculation (with PBSA Model Solvent) of alpha-Patchouli alcohol isomer compounds (CID442384, CID6432585, CID3080622, CID10955174, and CID56928117) was suggested as candidate for a selective COX-1 inhibitor and CID521903 as nonselective COX-1/COX-2. PMID:25484897

Induction of cyclo-oxygenase-2 mRNA by prostaglandin E2 in human prostatic carcinoma cells

NASA Technical Reports Server (NTRS)

Tjandrawinata, R. R.; Dahiya, R.; Hughes-Fulford, M.

1997-01-01

Prostaglandins are synthesized from arachidonic acid by the enzyme cyclo-oxygenase. There are two isoforms of cyclooxygenases: COX-1 (a constitutive form) and COX-2 (an inducible form). COX-2 has recently been categorized as an immediate-early gene and is associated with cellular growth and differentiation. The purpose of this study was to investigate the effects of exogenous dimethylprostaglandin E2 (dmPGE2) on prostate cancer cell growth. Results of these experiments demonstrate that administration of dmPGE2 to growing PC-3 cells significantly increased cellular proliferation (as measured by the cell number), total DNA content and endogenous PGE2 concentration. DmPGE2 also increased the steady-state mRNA levels of its own inducible synthesizing enzyme, COX-2, as well as cellular growth to levels similar to those seen with fetal calf serum and phorbol ester. The same results were observed in other human cancer cell types, such as the androgen-dependent LNCaP cells, breast cancer MDA-MB-134 cells and human colorectal carcinoma DiFi cells. In PC-3 cells, the dmPGE2 regulation of the COX-2 mRNA levels was both time dependent, with maximum stimulation seen 2 h after addition, and dose dependent on dmPGE2 concentration, with maximum stimulation seen at 5 microg ml(-1). The non-steroidal anti-inflammatory drug flurbiprofen (5 microM), in the presence of exogenous dmPGE2, inhibited the up-regulation of COX-2 mRNA and PC-3 cell growth. Taken together, these data suggest that PGE2 has a specific role in the maintenance of human cancer cell growth and that the activation of COX-2 expression depends primarily upon newly synthesized PGE2, perhaps resulting from changes in local cellular PGE2 concentrations.

Kupffer cell ablation attenuates cyclooxygenase-2 expression after trauma and sepsis.

PubMed

Keller, Steve A; Paxian, Marcus; Lee, Sun M; Clemens, Mark G; Huynh, Toan

2005-03-01

Prostaglandins, synthesized by cyclooxygenase (COX), play an important role in the pathophysiology of inflammation. Severe injuries result in immunosuppression, mediated, in part, by maladaptive changes in macrophages. Herein, we assessed Kupffer cell-mediated cyclooxygenase-2 (COX-2) expression on liver function and damage after trauma and sepsis. To ablate Kupffer cells, Sprague Dawley rats were treated with gadolinium chloride (GdCl3) 48 and 24 h before experimentation. Animals then underwent femur fracture (FFx) followed 48 h later by cecal ligation and puncture (CLP). Controls received sham operations. After 24 h, liver samples were obtained, and mRNA and protein expression were determined by PCR, Western blot, and immunohistochemistry. Indocyanine-Green (ICG) clearance and plasma alanine aminotransferase (ALT) levels were determined to assess liver function and damage, respectively. One-way analysis of variance (ANOVA) with Student-Newman-Keuls test was used to assess statistical significance. After CLP alone, FFx+CLP, and GdCl3+FFx+CLP, clearance of ICG decreased. Plasma ALT levels increased in parallel with severity of injury. Kupffer cell depletion attenuated the increased ALT levels after FFx+CLP. Femur fracture alone did not alter COX-2 protein compared with sham. By contrast, COX-2 protein increased after CLP and was potentiated by sequential stress. Again, Kupffer cell depletion abrogated the increase in COX-2 after sequential stress. Immunohistochemical data confirmed COX-2 positive cells to be Kupffer cells. In this study, sequential stress increased hepatic COX-2 protein. Depletion of Kupffer cells reduced COX-2 and attenuated hepatocellular injuries. Our data suggest that Kupffer cell-dependent pathways may contribute to the inflammatory response leading to increased mortality after sequential stress.

Cyclooxygenase-2 expression in the eyes of cats with and without uveitis.

PubMed

Sim, Zhi Hui; Pinard, Chantale L; Plattner, Brandon L; Bienzle, Dorothee

2018-01-01

OBJECTIVE To characterize the distribution and intensity of cyclooxygenase (COX)-2 expression in the eyes of cats with and without uveitis and to determine whether COX-2 expression is correlated with severity of inflammation. SAMPLES Archived ocular tissue specimens from 51 cats with and 10 cats without ocular disease. PROCEDURES Specimens from only 1 eye were evaluated for each cat. Specimens were stained with H&E stain or immunohistochemical stain for detection of COX-2 and reviewed. For each eye, the type, severity, and distribution of inflammation and the distribution and intensity of COX-2 expression were determined for the uvea and other ocular tissues. Correlation between COX-2 expression and inflammation severity was also assessed. RESULTS COX-2 was not expressed in any nondiseased eye. Of the 51 diseased eyes, 20 had histologic evidence of lymphocytic-plasmacytic uveitis, 13 had neutrophilic uveitis, 11 had diffuse iris melanoma with uveitis, and 7 had diffuse iris melanoma without uveitis. Of the 44 eyes with uveitis, COX-2 was detected in the uvea of 16, including 11 eyes with lymphocytic-plasmacytic uveitis, 4 with neutrophilic uveitis, and 1 with diffuse iris melanoma-induced uveitis. Inflammation was severe, moderate, or mild in 10, 5, and 1 of those eyes, respectively. Cyclooxygenase-2 was detected in the cornea of 21 eyes with uveitis and 1 eye with diffuse iris melanoma without uveitis. Uveitis severity was positively correlated with COX-2 expression in both the uvea and cornea. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that COX-2 is an inflammatory mediator in feline uveitis but not diffuse iris melanoma.

Expression of cyclooxygenase-1 and cyclooxygenase-2, syndecan-1 and connective tissue growth factor in benign and malignant breast tissue from premenopausal women.

PubMed

Fahlén, M; Zhang, H; Löfgren, L; Masironi, B; von Schoultz, E; von Schoultz, B; Sahlin, L

2017-05-01

Stromal factors have been identified as important for tumorigenesis and metastases of breast cancer. From 49 premenopausal women, samples were collected from benign or malignant tumors and the seemingly normal tissue adjacent to the tumor. The factors studied, with real-time polymerase chain reaction (PCR) and immunohistochemistry, were cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2), syndecan-1 (S-1) and connective tissue growth factor (CTGF). COX-1 and S-1 mRNA levels were higher in the malignant tumors than in normal and benign tissues. The COX-2 mRNA level was lower in the malignant tumor than in the normal tissue, while CTGF mRNA did not differ between the groups. COX-1 immunostaining was higher in stroma from malignant tumors than in benign tissues, whereas COX-2 immunostaining was higher in the malignant tissue. Glandular S-1 immunostaining was lower in malignant tumors compared to benign and normal tissues, and the opposite was found in stroma. Conclusively, mRNA levels of COX-1 and COX-2 were oppositely regulated, with COX-1 being increased in the malignant tumor while COX-2 was decreased. S-1 protein localization switched from glandular to stromal cells in malignant tissues. Thus, these markers are, in premenopausal women, localized and regulated differently in normal/benign breast tissue as compared to the malignant tumor.

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

PubMed Central

St-Onge, Mireille; Flamand, Nicolas; Biarc, Jordane; Picard, Serge; Bouchard, Line; Dussault, Andrée-Anne; Laflamme, Cynthia; James, Michael J.; Caughey, Gillian E.; Cleland, Leslie G.; Borgeat, Pierre; Pouliot, Marc

2010-01-01

In the present study, we characterized the generation of prostaglandin (PG)E2 in human neutrophils. We found that the Ca2+-dependent type IV cytosolic phospholipase A2 (cPLA2) was pivotally involved in the COX-2-mediated generation of PGE2 in response to a calcium ionophore, as determined by the use of selected PLA2 inhibitors. PGE2 biosynthesis elicited by bacterial-derived peptides or by phagocytic stimuli acting on cell surface receptors also showed to be dependent on cPLA2 activity. We then assessed metabolism of unesterified arachidonic acid (AA), and observed that PGE2 production becomes favored over that of LTB4 with higher AA concentrations. Withdrawal of calcium prevented the generation of PGE2 in response to a calcium ionophore but did not affect the up-regulation of COX-2 or its capacity to convert AA, thus limiting its implication at the level of cPLA2 activation. Of the main eicosanoids produced by neutrophils, only LTB4 was able to up-regulate COX-2 expression. Finally, the only PGE synthase isoform found in neutrophils is microsomal PGE synthase-1; it co-localized with COX-2 and its expression appeared mainly constitutive. These results highlight key differences in regulatory processes of the 5-LO and COX pathways, and enhance our knowledge at several levels in the PGE2 biosynthesis in neutrophils. PMID:17643350

Detection of Cyclooxygenase-2-Derived Oxygenation Products of the Endogenous Cannabinoid 2-Arachidonoylglycerol in Mouse Brain.

PubMed

Morgan, Amanda J; Kingsley, Philip J; Mitchener, Michelle M; Altemus, Megan; Patrick, Toni A; Gaulden, Andrew D; Marnett, Lawrence J; Patel, Sachin

2018-05-09

Cyclooxygenase-2 (COX-2) catalyzes the formation of prostaglandins, which are involved in immune regulation, vascular function, and synaptic signaling. COX-2 also inactivates the endogenous cannabinoid (eCB) 2-arachidonoylglycerol (2-AG) via oxygenation of its arachidonic acid backbone to form a variety of prostaglandin glyceryl esters (PG-Gs). Although this oxygenation reaction is readily observed in vitro and in intact cells, detection of COX-2-derived 2-AG oxygenation products has not been previously reported in neuronal tissue. Here we show that 2-AG is metabolized in the brain of transgenic COX-2-overexpressing mice and mice treated with lipopolysaccharide to form multiple species of PG-Gs that are detectable only when monoacylglycerol lipase is concomitantly blocked. Formation of these PG-Gs is prevented by acute pharmacological inhibition of COX-2. These data provide evidence that neuronal COX-2 is capable of oxygenating 2-AG to form a variety PG-Gs in vivo and support further investigation of the physiological functions of PG-Gs.

COX-2 overexpression in resected pancreatic head adenocarcinomas correlates with favourable prognosis

PubMed Central

2014-01-01

Background Overexpression of cyclooxygenase-2 (COX-2) has been implicated in oncogenesis and progression of adenocarcinomas of the pancreatic head. The data on the prognostic importance of COX expression in these tumours is inconsistent and conflicting. We evaluated how COX-2 overexpression affected overall postoperative survival in pancreatic head adenocarcinomas. Methods The study included 230 consecutive pancreatoduodenectomies for pancreatic cancer (PC, n = 92), ampullary cancer (AC, n = 62) and distal bile duct cancer (DBC, n = 76). COX-2 expression was assessed by immunohistochemistry. Associations between COX-2 expression and histopathologic variables including degree of differentiation, histopathologic type of differentiation (pancreatobiliary vs. intestinal) and lymph node ratio (LNR) were evaluated. Unadjusted and adjusted survival analysis was performed. Results COX-2 staining was positive in 71% of PC, 77% in AC and 72% in DBC. Irrespective of tumour origin, overall patient survival was more favourable in patients with COX-2 positive tumours than COX-2 negative (p = 0.043 in PC, p = 0.011 in AC, p = 0.06 in DBC). In tumours of pancreatobiliary type of histopathological differentiation, COX-2 expression did not significantly affect overall patient survival. In AC with intestinal differentiation COX-2 expression significantly predicted favourable survival (p = 0.003). In PC, COX-2 expression was significantly associated with high degree of differentiation (p = 0.002). COX-2 and LNR independently predicted good prognosis in a multivariate model. Conclusions COX-2 is overexpressed in pancreatic cancer, ampullary cancer and distal bile duct cancer and confers a survival benefit in all three cancer types. In pancreatic cancer, COX-2 overexpression is significantly associated with the degree of differentiation and independently predicts a favourable prognosis. PMID:24950702

Oxymatrine attenuated isoproterenol-induced heart failure in rats via regulation of COX-2/PGI2 pathway.

PubMed

Zhou, Ru; Xu, Qingbin; Xu, Yehua; Xiong, Aiqin; Wang, Yang; Ma, Ping

2016-12-01

Oxymatrine (OMT) is an active constituent of traditional Chinese herb Sophora japonica Ait which has been shown to exert potent anti-inflammatory,anti-oxidant and anti-fibrosis properties. Our previous studies have demonstrated that OMT has protective effects on isoproterenol-induced heart failure in rats through regulation of DDAH/ADMA metabolism pathway.In this study,we further investigated whether OMT could attenuate isoproterenol-induced heart failure through the regulation of COX-2/PGI 2 pathway. Heart failure was induced in Sprague-Dawley rats by 5mg/kg isoproterenol subcutaneous injection for 7days. The rats were maintained on normal diet and randomly divided into five groups: control, isoproterenol, isoproterenol with OMT (50, 100mg/kg), and OMT alone groups (n=12 in each group). Serum brain natruretic peptide (BNP, a heart failure biomarker), histopathological variables, expression of Cytosolic phospholipase A 2 (cPLA 2 ), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and Prostacyclin synthase (PGIS) were analysed. Administration of OMT significantly reduced the increased BNP in plasm of isoproterenol-induced rats, attenuated cardiac fibrosis,suppressed overexpression of myocardial COX-1 expression, up-regulated COX-2 and PGIS expression, but had no effects on isoproterenol-induced elevated protein cPLA 2 . And compared with control group, any indexes in sham rats treated with OMT (100mg/kg) alone were unaltered. These results demonstrated that OMT has cardioprotective effects on isoproterenol-induced heart failure in rats by regulating COX-2/PGI 2 pathway. Copyright © 2016. Published by Elsevier Masson SAS.

Constitutive cyclooxygenase-2 is involved in central nociceptive processes in humans

PubMed Central

Martin, Frédéric; Fletcher, Dominique; Chauvin, Marcel; Bouhassira, Didier

2007-01-01

Background Prostaglandins play a major role in inflammation and pain. They are synthesised by the two cyclooxygenase (COX) isoforms: COX-1, which is expressed constitutively in many cell types and COX-2, which is induced at the site of inflammation. However, unlike peripheral tissues, COX-2 is expressed constitutively in the central nervous system and may play a role in nociceptive processes. The present study aimed to investigate the role of constitutive COX-2 in the spinal transmission of nociceptive signals in humans. Methods We used 12 healthy volunteers to compare the effects of the specific COX-2 inhibitor sodium parecoxib (1 mg/kg) or placebo, administered intravenously in a double-blind and cross-over fashion, on the electrophysiological recordings of the nociceptive flexion (RIII) reflex. The RIII reflex is an objective psychophysiological index of the spinal transmission of nociceptive signals and was recorded from the biceps femoris after electrical stimulation of the sural nerve. Two experiments, seven days apart, were carried out on each volunteer. On each experimental day, the effects of parecoxib or placebo were tested on: 1) the RIII reflex threshold, 2) the stimulus-response curves of the reflex up to the tolerance threshold (frequency of stimulation: 0.1 Hz); 3) the progressive increase of the reflex and pain sensations (i.e. “wind-up” phenomenon) induced by a series of 15 stimulations at a frequency of 1 Hz (intensity 20% above RIII threshold). Results Parecoxib, but not placebo, significantly reduced the slope of the stimulus-response curve, suggesting a reduction in the gain of the spinal transmision of nociceptive signals. By contrast, the “wind-up” phenomenon was not significantly altered after administration of parecoxib or placebo. Conclusions Our study shows that constitutive COX-2 modulates spinal nociceptive processes and that the anti-inflammatory and antinociceptive actions of COX-2 inhibitors are not necessarily related. PMID

Inhibition of bacterial multidrug resistance by celecoxib, a cyclooxygenase-2 inhibitor.

PubMed

Kalle, Arunasree M; Rizvi, Arshad

2011-01-01

Multidrug resistance (MDR) is a major problem in the treatment of infectious diseases and cancer. Accumulating evidence suggests that the cyclooxygenase-2 (COX-2)-specific inhibitor celecoxib would not only inhibit COX-2 but also help in the reversal of drug resistance in cancers by inhibiting the MDR1 efflux pump. Here, we demonstrate that celecoxib increases the sensitivity of bacteria to the antibiotics ampicillin, kanamycin, chloramphenicol, and ciprofloxacin by accumulating the drugs inside the cell, thus reversing MDR in bacteria.

Identification of novel Cyclooxygenase-2-dependent genes in Helicobacter pylori infection in vivo

PubMed Central

Walduck, Anna K; Weber, Matthias; Wunder, Christian; Juettner, Stefan; Stolte, Manfred; Vieth, Michael; Wiedenmann, Bertram; Meyer, Thomas F; Naumann, Michael; Hoecker, Michael

2009-01-01

Background Helicobacter pylori is a crucial determining factor in the pathogenesis of benign and neoplastic gastric diseases. Cyclooxygenase-2 (Cox-2) is the inducible key enzyme of arachidonic acid metabolism and is a central mediator in inflammation and cancer. Expression of the Cox-2 gene is up-regulated in the gastric mucosa during H. pylori infection but the pathobiological consequences of this enhanced Cox-2 expression are not yet characterized. The aim of this study was to identify novel genes down-stream of Cox-2 in an in vivo model, thereby identifying potential targets for the study of the role of Cox- 2 in H. pylori pathogenesis and the initiation of pre- cancerous changes. Results Gene expression profiles in the gastric mucosa of mice treated with a specific Cox-2 inhibitor (NS398) or vehicle were analysed at different time points (6, 13 and 19 wk) after H. pylori infection. H. pylori infection affected the expression of 385 genes over the experimental period, including regulators of gastric physiology, proliferation, apoptosis and mucosal defence. Under conditions of Cox-2 inhibition, 160 target genes were regulated as a result of H. pylori infection. The Cox-2 dependent subset included those influencing gastric physiology (Gastrin, Galr1), epithelial barrier function (Tjp1, connexin45, Aqp5), inflammation (Icam1), apoptosis (Clu) and proliferation (Gdf3, Igf2). Treatment with NS398 alone caused differential expression of 140 genes, 97 of which were unique, indicating that these genes are regulated under conditions of basal Cox-2 expression. Conclusion This study has identified a panel of novel Cox-2 dependent genes influenced under both normal and the inflammatory conditions induced by H. pylori infection. These data provide important new links between Cox-2 and inflammatory processes, epithelial repair and integrity. PMID:19317916

Cyclic stretch induces cyclooxygenase-2 gene expression in vascular endothelial cells via activation of nuclear factor kappa-{beta}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Haige; Hiroi, Toyoko; Hansen, Baranda S.

2009-11-27

Vascular endothelial cells respond to biomechanical forces, such as cyclic stretch and shear stress, by altering gene expression. Since endothelial-derived prostanoids, such as prostacyclin and thromboxane A{sub 2}, are key mediators of endothelial function, we investigated the effects of cyclic stretch on the expression of genes in human umbilical vein endothelial cells controlling prostanoid synthesis: cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), prostacyclin synthase (PGIS) and thromboxane A{sub 2} synthase (TXAS). COX-2 and TXAS mRNAs were upregulated by cyclic stretch for 24 h. In contrast, PGIS mRNA was decreased and stretch had no effect on COX-1 mRNA expression. We further show that stretch-inducedmore » upregulation of COX-2 is mediated by activation of the NF-{kappa}{beta} signaling pathway.« less

Role of cyclooxygenase-2 in intestinal injury in neonatal rats.

PubMed

Lu, Hui; Zhu, Bing

2014-11-01

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature neonates. The pathogenesis of NEC remains poorly understood. The present study aimed to investigate the dynamic change and role of cyclooxygenase-2 (COX-2) in neonatal rats with intestinal injury. Wistar rats, <24 h in age, received an intraperitoneal injection with 5 mg/kg lipopolysaccharide (LPS). Ileal tissues were collected at 1, 3, 6, 12 and 24 h following the LPS challenge for histological evaluation of NEC and for measurements of COX-2 mRNA. The correlation between the degree of intestinal injury and expression of COX-2 mRNA was determined. The LPS-injected pups showed a significant increase in injury scores compared to the control, and the most deteriorating change was at 12 h. COX-2 mRNA expression was upregulated following LPS injection. There was a significantly positive correlation between COX-2 mRNA and the grade of intestinal injury within 12 h, whereas COX-2 mRNA expression had a significantly negative correlation with the severity of intestinal injury at 24 h. COX-2 plays an important role in LPS-induced intestinal injury and the repair processes. Caution should be exerted concerning the potential therapeutic uses of COX-2 inhibitors or promoters in NEC.

Resveratrol Directly Targets COX-2 to Inhibit Carcinogenesis

PubMed Central

Zykova, Tatyana A.; Zhu, Feng; Zhai, Xiuhong; Ma, Wei-ya; Ermakova, Svetlana P.; Lee, Ki Won; Bode, Ann M.; Dong, Zigang

2008-01-01

Targeted molecular cancer therapies can potentially deliver treatment directly to a specific protein or gene to optimize efficacy and reduce adverse side effects often associated with traditional chemotherapy. Key oncoprotein and oncogene targets are rapidly being identified based on their expression, pathogenesis and clinical outcome. One such protein target is cyclooxygenase-2 (COX-2), which is highly expressed in various cancers. Research findings suggest that resveratrol (3,5,4'-trihydroxy-trans-stilbene) demonstrates non-selective COX-2 inhibition. We report herein that resveratrol (RSVL) directly binds with COX-2 and this binding is absolutely required for RSVL's inhibition of the ability of human colon adenocarcinoma HT-29 cells to form colonies in soft agar. Binding of COX-2 with RSVL was compared with two RSVL analogues, 3,3’,4’,5’5’-pentahydroxy-trans-stilbene (RSVL-2) or 3,4’,5-trimethoxy-trans-stilbene (RSVL-3). The results indicated that COX-2 binds with RSVL-2 more strongly than with RSVL, but does not bind with RSVL-3. RSVL or RSVL-2, but not RSVL-3, inhibited COX-2-mediated PGE2 production in vitro and ex vivo. HT-29 human colon adenocarcinoma cells express high levels of COX-2 and either RSVL or RSVL-2, but not RSVL-3, suppressed anchorage independent growth of these cells in soft agar. RSVL or RSVL-2 (not RSVL-3) suppressed growth of COX-2+/+ cells by 60 or 80%, respectively. Notably, cells deficient in COX-2 were unresponsive to RSVL or RSVL-2. These data suggest that the anticancer effects of RSVL or RSLV-2 might be mediated directly through COX-2. PMID:18381589

P38 AND EGF RECEPTOR KINASE-MEDIATED ACTIVATION OF THE PHOSPHATIDYLINOSITOL 3-KINASE/AKT PATHWAY IS REQUIRED FOR ZN2+INDUCED CYCLOOXYGENASE-2 EXPRESSION

EPA Science Inventory

Cyclooxygenase 2 (COX-2) expression is induced by physiological and inflammatory stimuli. Regulation of COX-2 expression is stimulus- and cell type-specific. Exposure to Zn2+ has been associated with activation of multiple intracellular signaling pathways as well as the induction...

Surface plasmon resonance studies and biochemical evaluation of a potent peptide inhibitor against cyclooxygenase-2 as an anti-inflammatory agent.

PubMed

Somvanshi, Rishi K; Kumar, Ashwini; Kant, Shashi; Gupta, Deepti; Singh, S Bhaskar; Das, Utpal; Srinivasan, Alagiri; Singh, Tej P; Dey, Sharmistha

2007-09-14

Cyclooxygenase (COX) is a key enzyme in the biosynthetic pathway leading to the formation of prostaglandins, which are mediators of inflammation [D.L. Dewitt, W.L. Smith, Primary structure of prostaglandin G/H synthase from sheep vesicular gland determined from the complementary DNA sequence, Proc. Natl. Acad. Sci. USA 85 (1988) 1412-1416, 1]. It exists mainly in two isoforms COX-1 and COX-2 [A. Raz, A. Wyche, N. Siegel, P. Needleman, Regulation of fibroblast cyclooxygenase synthesis by interleukin-1, J. Biol. Chem. 263 (1988) 3022-3028, 2]. The conventional non-steroidal anti-inflammatory drugs (NSAIDs) have adverse gastrointestinal side-effects, because they inhibit both isoforms [T.D. Warner, F. Guiliano, I. Vojnovic, A. Bukasa, J.A. Mitchell, J.P. Vane, Nonsteroid drug selectivities for cyclo-oxygenase-1 rather than cyclo-oxygenase-2 are associated with human gastrointestinal toxicity: a full in vitro analysis, Proc. Natl. Acad. Sci. USA 96 (1999) 7563-7568, 3; L.J. Marnett, A.S. Kalgutkar, Cyclooxygenase 2 inhibitors: discovery, selectivity and the future, Trends Pharmacol. Sci. 20 (1999) 465-469, 4; J.R. Vane, NSAIDs, Cox-2 inhibitors, and the gut, Lancet 346 (1995) 1105-1106, 5]. Therefore drugs which selectively inhibit COX-2, known as coxibs were developed. Recent reports on the harmful cardiovascular and renovascular side-effects of the anti-inflammatory drugs have led to the quest for a novel class of COX-2 selective inhibitors. Keeping this in mind, we have used the X-ray crystal structures of the complexes of the COX-1 and COX-2 with the known inhibitors for a rational, structure based approach to design a small peptide, which is potent inhibitor for COX-2. The peptides have been checked experimentally by in-vitro kinetic studies using surface plasmon resonance (SPR) and other biochemical methods. We have identified a tripeptide inhibitor which is a potential lead for a new class of COX-2 inhibitor. The dissociation constant (K(D)) determined for COX-2

Alpha-tocopherol succinate increases cyclooxygenase-2 activity: Tissue-specific action in pregnant rat uterus in vitro.

PubMed

Kothencz, Anna; Hajagos-Tóth, Judit; Csányi, Adrienn; Gáspár, Róbert

2018-01-01

Lipid soluble vitamin E plays a role in several physiological mechanisms, however, the mechanism of this action is controversial. We investigated how tocopherol (α-tocopherol acid succinate) influences the effects of cyclooxygenase inhibitors (COXi) in the smooth muscles. The contractility of the samples from 22-day-pregnant myometrium and non-pregnant myometrium and trachea was determined in an isolated organ bath in vitro. The activity of cyclooxygenase enzymes (COX) was also measured in the tissues. Diclofenac (10 -9 -10 -5 M) and rofecoxib (10 -10 -10 -5 M) decreased the contractions in non-pregnant and 22-day-pregnant uteri. Tocopherol (10 -7 M) increased the relaxant effect only in pregnant uteri. Both diclofenac (10 -9 -10 -5 M) and rofecoxib (10 -10 -10 -5 M) reduced the tracheal tones, while they were slightly intensified by pretreatment with tocopherol (10 -7 M). Tocopherol enhanced the contractions of pregnant uteri. Tocopherol (10 -7 M) itself can induce the cyclooxygenase activity and shift the COX-1 and COX-2 ratio to COX-2. The lowest COX activity was found in non-pregnant uteri, while the highest one was in the trachea. The COX enzymes, especially COX-2, play an important role in the contraction of pregnant uteri in rat. Tocopherol has a tissue specific COX-2 activity increasing effect in pregnant rat uterus but has no such action in non-pregnant uteri or tracheal tissue. Hereby, tocopherol may intensify selectively the uterine relaxing effect of COX-2 inhibitors in preterm contractions. However, tocopherol can enhance the contractile response of pregnant uterus that may increase the risk of premature contractions. Copyright © 2017 Elsevier Inc. All rights reserved.

Cyclooxygenase-2 inhibitors modulate skin aging in a catalytic activity-independent manner

PubMed Central

Lee, Mi Eun; Kim, So Ra; Lee, Seungkoo; Jung, Yu-Jin; Choi, Sun Shim; Kim, Woo Jin

2012-01-01

It has been proposed that the pro-inflammatory catalytic activity of cyclooxygenase-2 (COX-2) plays a key role in the aging process. However, it remains unclear whether the COX-2 activity is a causal factor for aging and whether COX-2 inhibitors could prevent aging. We here examined the effect of COX-2 inhibitors on aging in the intrinsic skin aging model of hairless mice. We observed that among two selective COX-2 inhibitors and one non-selective COX inhibitor studied, only NS-398 inhibited skin aging, while celecoxib and aspirin accelerated skin aging. In addition, NS-398 reduced the expression of p53 and p16, whereas celecoxib and aspirin enhanced their expression. We also found that the aging-modulating effect of the inhibitors is closely associated with the expression of type I procollagen and caveolin-1. These results suggest that pro-inflammatory catalytic activity of COX-2 is not a causal factor for aging at least in skin and that COX-2 inhibitors might modulate skin aging by regulating the expression of type I procollagen and caveolin-1. PMID:22771771

Lactoferrin from Camelus dromedarius Inhibits Nuclear Transcription Factor-kappa B Activation, Cyclooxygenase-2 Expression and Prostaglandin E2 Production in Stimulated Human Chondrocytes

PubMed Central

Rasheed, Naila; Alghasham, Abdullah; Rasheed, Zafar

2016-01-01

Background: Osteoarthritis (OA) is a progressive joint disorder, which remains the leading cause of chronic disability in aged people. Nuclear factor-kappa B (NF)-κB is a major cellular event in OA and its activation by interleukin-1β (IL-1β) plays a critical role in cartilage breakdown in these patients. Objective: In this study, we examined the effect of lactoferrin on NF-κB activation, cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) production in stimulated human articular chondrocytes. Materials and Methods: Human chondrocytes were derived from OA articular cartilage and treated with camel lactoferrin and then stimulated with IL-1β. Gene expression was determined by TaqMan assays and protein expression was studied by Western immunoblotting. NF-κB activity and PGE2 levels were determined by ELISA based assays. NF-κB activity was also determined by treatment of chondrocytes with NF-κB specific inhibitor Bay 11–7082. Results: Lactoferrin inhibited IL-1β-induced activation and nuclear translocation of NF-κB p65 in human OA chondrocytes. Lactoferrin also inhibited mRNA/protein expression of COX-2 and production of PGE2. Moreover, Bay 11–7082 also inhibited IL-1β-induced expression of COX-2 and production of PGE2. The inhibitory effect of lactoferrin on the IL-1β induced expression of COX-2 or production of PGE2 was mediated at least in part via suppression of NF-κB activation. Conclusions: Our data determine camel lactoferrin as a novel inhibitor of IL-1β-induced activation of NF-κB signaling events and production of cartilage-degrading molecule PGE2 via inhibition of COX-2 expressions. These results may have important implications for the development of novel therapeutic strategies for the prevention/treatment of OA and other degenerative/inflammatory diseases. SUMMARY Lactoferrin shows anti-arthritic activity in IL-1β stimulated primary human chondrocytes.Lactoferrin inhibits IL-1β-induced NF-κB activation.Lactoferrin inhibits

Staurosporine synergistically potentiates the deoxycholate-mediated induction of COX-2 expression.

PubMed

Saeki, Tohru; Inui, Haruka; Fujioka, Saya; Fukuda, Suguru; Nomura, Ayumi; Nakamura, Yasushi; Park, Eun Young; Sato, Kenji; Kanamoto, Ryuhei

2014-08-01

Colorectal cancer is a major cause of cancer-related death in western countries, and thus there is an urgent need to elucidate the mechanism of colorectal tumorigenesis. A diet that is rich in fat increases the risk of colorectal tumorigenesis. Bile acids, which are secreted in response to the ingestion of fat, have been shown to increase the risk of colorectal tumors. The expression of cyclooxygenase (COX)-2, an inducible isozyme of cyclooxygenase, is induced by bile acids and correlates with the incidence and progression of cancers. In this study, we investigated the signal transduction pathways involved in the bile-acid-mediated induction of COX-2 expression. We found that staurosporine (sts), a potent protein kinase C (PKC) inhibitor, synergistically potentiated the deoxycholate-mediated induction of COX-2 expression. Sts did not increase the stabilization of COX-2 mRNA. The sts- and deoxycholate-mediated synergistic induction of COX-2 expression was suppressed by a membrane-permeable Ca(2+) chelator, a phosphoinositide 3-kinase inhibitor, a nuclear factor-κB pathway inhibitor, and inhibitors of canonical and stress-inducible mitogen-activated protein kinase pathways. Inhibition was also observed using PKC inhibitors, suggesting the involvement of certain PKC isozymes (η, θ, ι, ζ, or μ). Our results indicate that sts exerts its potentiating effects via the phosphorylation of p38. However, the effects of anisomycin did not mimic those of sts, indicating that although p38 activation is required, it does not enhance deoxycholate-induced COX-2 expression. We conclude that staurosporine synergistically enhances deoxycholate-induced COX-2 expression in RCM-1 colon cancer cells. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Compensatory Hypertrophy Induced by Ventricular Cardiomyocyte Specific COX-2 Expression in Mice

PubMed Central

Streicher, John M.; Kamei, Kenichiro; Ishikawa, Tomo-o; Herschman, Harvey; Wang, Yibin

2010-01-01

Cyclooxygenase-2 (COX-2) is an important mediator of inflammation in stress and disease states. Recent attention has focused on the role of COX-2 in human heart failure and diseases, due to the finding that highly specific COX-2 inhibitors (i.e. Vioxx) increased the risk of myocardial infarction and stroke in chronic users. However, the specific impact of COX-2 expression in the intact heart remains to be determined. We report here the development of a transgenic mouse model, using a loxP-Cre approach, that displays robust COX-2 overexpression and subsequent prostaglandin synthesis specifically in ventricular myocytes. Histological, functional and molecular analyses showed that ventricular myocyte specific COX-2 overexpression led to cardiac hypertrophy and fetal gene marker activation, but with preserved cardiac function. Therefore, specific induction of COX-2 and prostaglandin in vivo is sufficient to induce compensated hypertrophy and molecular remodeling. PMID:20170663

Radiation Therapy Overcomes Adverse Prognostic Role of Cyclooxygenase-2 Expression on Reed-Sternberg Cells in Early Hodgkin Lymphoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mestre, Francisco; Gutiérrez, Antonio, E-mail: antoniom.gutierrez@ssib.es; Rodriguez, Jose

Purpose: To analyze the role of radiation therapy (RT) on the adverse prognostic influence of cyclooxygenase-2 (COX-2) expression on Reed-Sternberg (RS) cells, in the setting of early Hodgkin lymphoma (HL) treated with ABVD (adriamycin, vinblastine, bleomycin, dacarbazine). Methods and Materials: In the present study we retrospectively investigated the prognostic value of COX-2 expression in a large (n=143), uniformly treated early HL population from the Spanish Network of HL using tissue microarrays. Univariate and multivariate analyses were done, including the most recognized clinical variables and the potential role of administration of adjuvant RT. Results: Median age was 31 years; the expression of COX-2more » defined a subgroup with significantly worse prognosis. Considering COX-2{sup +} patients, those who received RT had significantly better 5-year progression-free survival (PFS) (80% vs 54% if no RT; P=.008). In contrast, COX-2{sup −} patients only had a modest, nonsignificant benefit from RT in terms of 5-year PFS (90% vs 79%; P=.13). When we compared the outcome of patients receiving RT considering the expression of COX-2 on RS cells, we found a nonsignificant 10% difference in terms of PFS between COX-2{sup +} and COX-2{sup −} patients (P=.09), whereas the difference between the 2 groups was important (25%) in patients not receiving RT (P=.04). Conclusions: Cyclooxygenase-2 RS cell expression is an adverse independent prognostic factor in early HL. Radiation therapy overcomes the worse prognosis associated with COX-2 expression on RS cells, acting in a chemotherapy-independent way. Cyclooxygenase-2 RS cell expression may be useful for determining patient candidates with early HL to receive consolidation with RT.« less

COX-2-derived endocannabinoid metabolites as novel inflammatory mediators.

PubMed

Alhouayek, Mireille; Muccioli, Giulio G

2014-06-01

Cyclooxygenase-2 (COX-2) is an enzyme that plays a key role in inflammatory processes. Classically, this enzyme is upregulated in inflammatory situations and is responsible for the generation of prostaglandins (PGs) from arachidonic acid (AA). One lesser-known property of COX-2 is its ability to metabolize the endocannabinoids, N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG). Endocannabinoid metabolism by COX-2 is not merely a means to terminate their actions. On the contrary, it generates PG analogs, namely PG-glycerol esters (PG-G) for 2-AG and PG-ethanolamides (PG-EA or prostamides) for AEA. Although the formation of these COX-2-derived metabolites of the endocannabinoids has been known for a while, their biological effects remain to be fully elucidated. Recently, several studies have focused on the role of these PG-G or PG-EA in vivo. In this review we take a closer look at the literature concerning these novel bioactive lipids and their role in inflammation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Selective inhibition of inducible cyclooxygenase 2 in vivo is antiinflammatory and nonulcerogenic.

PubMed Central

Masferrer, J L; Zweifel, B S; Manning, P T; Hauser, S D; Leahy, K M; Smith, W G; Isakson, P C; Seibert, K

1994-01-01

We have examined the role of cyclooxygenase 2 (COX-2) in a model of inflammation in vivo. Carrageenan administration to the subcutaneous rat air pouch induces a rapid inflammatory response characterized by high levels of prostaglandins (PGs) and leukotrienes in the fluid exudate. The time course of the induction of COX-2 mRNA and protein coincided with the production of PGs in the pouch tissue and cellular infiltrate. Carrageenan-induced COX-2 immunoreactivity was localized to macrophages obtained from the fluid exudate as well as to the inner surface layer of cells within the pouch lining. Dexamethasone inhibited both COX-2 expression and PG synthesis in the fluid exudate but failed to inhibit PG synthesis in the stomach. Furthermore, NS-398, a selective COX-2 inhibitor, and indomethacin, a nonselective COX-1/COX-2 inhibitor, blocked proinflammatory PG synthesis in the air pouch. In contrast, only indomethacin blocked gastric PG and, additionally, produced gastric lesions. These results suggest that inhibitors of COX-2 are potent antiinflammatory agents which do not produce the typical side effects (e.g., gastric ulcers) associated with the nonselective, COX-1-directed antiinflammatory drugs. Images PMID:8159730

[Cyclooxygenase-2: a new therapeutic target in atherosclerosis?].

PubMed

Páramo, José A; Beloqui, Oscar; Orbe, Josune

2006-05-27

It is now widely accepted that atherosclerosis is a complex chronic inflammatory disorder of the arterial tree associated with several risk factors. From the initial phases to eventual rupture of vulnerable atherosclerotic plaques, a low-grade inflammation, also termed microinflammation, appears to play a key pathogenetic role. Systemic inflammatory markers (C reactive protein, cytokines adhesion molecules) also play a role in this process. Experimental and clinical evidence suggests that cyclooxygenase-2 (COX-2), an enzyme which catalyzes the generation of prostaglandins from arachidonic acid, also contributes to lesion formation. Recent reports by our group have demonstrated increased monocyte COX-2 activity and the production of prostaglandin E2 in relation to cardiovascular risk factors and subclinical atherosclerosis in asymptomatic subjects. Our findings support the notion that the COX-2/prostaglandin E2 axis may have a role, raising the question as to whether its selective inhibition might be an attractive therapeutic target in atherosclerosis. COX-2 inhibitors, collectively called "coxibs" (celecoxib, rofecoxib, valdecoxib, lumiracoxib, etc), held a promise as anti-inflammatory drugs without the some of the side effects of aspirin or non steroidal antiinflammatory agents. However, clinical studies raise several clinically relevant questions as to their beneficial role in atherosclerosis prevention, because of increased thrombogenicity and cardiovascular risk, and therefore coxibs should be restricted in atherosclerosis-prone patients.

COX-1 vs. COX-2 as a determinant of basal tone in the internal anal sphincter.

PubMed

de Godoy, Márcio A F; Rattan, Neeru; Rattan, Satish

2009-02-01

Prostanoids, produced endogenously via cyclooxygenases (COXs), have been implicated in the sustained contraction of different smooth muscles. The two major types of COXs are COX-1 and COX-2. The COX subtype involved in the basal state of the internal anal sphincter (IAS) smooth muscle tone is not known. To identify the COX subtype, we examined the effect of COX-1- and COX-2-selective inhibitors, SC-560 and rofecoxib, respectively, on basal tone in the rat IAS. We also determined the effect of selective deletion of COX-1 and COX-2 genes (COX-1(-/-) and COX-2(-/-) mice) on basal tone in murine IAS. Our data show that SC-560 causes significantly more efficacious and potent concentration-dependent decreases in IAS tone than rofecoxib. In support of these data, significantly higher levels of COX-1 than COX-2 mRNA were found in the IAS. In addition, higher levels of COX-1 mRNA and protein were expressed in rat IAS than rectal smooth muscle. In wild-type mice, IAS tone was decreased 41.4 +/- 3.4% (mean +/- SE) by SC-560 (1 x 10(-5) M) and 5.4 +/- 2.2% by rofecoxib (P < 0.05, n = 5). Basal tone was 0.172 +/- 0.021 mN//mg in the IAS from wild-type mice and significantly less (0.080 +/- 0.015 mN/mg) in the IAS from COX-1(-/-) mice (P < 0.05, n = 5). However, basal tone in COX-2(-/-) mice was not significantly different from that in wild-type mice. We conclude that COX-1-related products contribute significantly to IAS tone.

Anti-inflammatory, cyclooxygenase (COX)-2, COX-1 inhibitory, and free radical scavenging effects of Rumex nepalensis.

PubMed

Gautam, Raju; Karkhile, Kailas V; Bhutani, Kamlesh K; Jachak, Sanjay M

2010-10-01

Evaluation of the topical anti-inflammatory activity of chloroform and ethyl acetate extracts of RUMEX NEPALENSIS roots in a TPA-induced acute inflammation mouse model demonstrated a significant reduction in ear edema. The extracts were further tested on purified enzymes for COX-1 and COX-2 inhibition to elucidate their mechanism of action, and a strong inhibition was observed. Six anthraquinones and two naphthalene derivatives were isolated from the ethyl acetate extract. Among the isolated compounds, emodin was found to be a potent inhibitor with slight selectivity towards COX-2, and nepodin exhibited selectivity towards COX-1. Emodin, endocrocin, and nepodin also exhibited significant topical anti-inflammatory activity in mice. Interestingly, nepodin showed better radical scavenging activity than trolox and ascorbic acid against DPPH and ABTS radicals. The strong radical scavenging activity of chloroform and ethyl acetate extracts could be explained by the presence of nepodin as well as by the high phenolic content of the ethyl acetate extract. Thus, the anti-inflammatory effect of R. NEPALENSIS roots was assumed to be mediated through COX inhibition by anthraquinones and naphthalene derivatives and through the radical scavenging activities of naphthalene derivatives. © Georg Thieme Verlag KG Stuttgart · New York.

Expression of cyclooxygenase-2 in transitional cell carcinoma of the urinary bladder in dogs.

PubMed

Khan, K N; Knapp, D W; Denicola, D B; Harris, R K

2000-05-01

To evaluate expression of cyclooxygenase (COX)-1 and COX-2 in the urinary bladder epithelium of clinically normal dogs and in transitional cell carcinoma cells of dogs. 21 dogs with transitional cell carcinoma of the urinary bladder and 8 dogs with clinically normal urinary bladders. COX-1 and COX-2 were evaluated by use of isoform-specific antibodies with standard immunohistochemical methods. COX-1, but not COX-2, was constitutively expressed in normal urinary bladder epithelium; however, COX-2 was expressed in neoplastic epithelium in primary tumors and in metastatic lesions of all 21 dogs and in new proliferating blood vessels in 3 dogs. Also, COX-1 was expressed in the neoplastic cells. Lack of expression of COX-2 in normal bladder epithelium and its substantial expression in transitional cell carcinoma cells suggest that this isoform may be involved in tumor cell growth. Inhibition of COX-2 is a likely mechanism of the antineoplastic effects of non steroidal antiinflammatory drugs.

Brain-targeted ACE2 overexpression attenuates neurogenic hypertension by inhibiting COX mediated inflammation

PubMed Central

Sriramula, Srinivas; Xia, Huijing; Xu, Ping; Lazartigues, Eric

2014-01-01

Overactivity of the renin angiotensin system (RAS), oxidative stress, and cyclooxygenases (COX) in the brain are implicated in the pathogenesis of hypertension. We previously reported that Angiotensin-Converting Enzyme 2 (ACE2) overexpression in the brain attenuates the development of DOCA-salt hypertension, a neurogenic hypertension model with enhanced brain RAS and sympathetic activity. To elucidate the mechanisms involved, we investigated whether oxidative stress, mitogen activated protein kinase signaling and cyclooxygenase (COX) activation in the brain are modulated by ACE2 in neurogenic hypertension. DOCA-salt hypertension significantly increased expression of Nox-2 (+61 ±5 %), Nox-4 (+50 ±13 %) and nitrotyrosine (+89 ±32 %) and reduced activity of the antioxidant enzymes, catalase (−29 ±4 %) and SOD (−31 ±7 %), indicating increased oxidative stress in the brain of non-transgenic mice. This increased oxidative stress was attenuated in transgenic mice overexpressing ACE2 in the brain. DOCA-salt-induced reduction of nNOS expression (−26 ±7 %) and phosphorylated eNOS/total eNOS (−30 ±3 %), and enhanced phosphorylation of Akt and ERK1/2 in the paraventricular nucleus (PVN), were reversed by ACE2 overexpression. In addition, ACE2 overexpression blunted the hypertension-mediated increase in gene and protein expression of COX-1 and COX-2 in the PVN. Furthermore, gene silencing of either COX-1 or COX-2 in the brain, reduced microglial activation and accompanied neuro-inflammation, ultimately attenuating DOCA-salt hypertension. Together, these data provide evidence that brain ACE2 overexpression reduces oxidative stress and COX-mediated neuro-inflammation, improves anti-oxidant and nitric oxide signaling, and thereby attenuates the development of neurogenic hypertension. PMID:25489058

The influence of cyclooxygenase-1 expression on the efficacy of cyclooxygenase-2 inhibition in head and neck squamous cell carcinoma cell lines.

PubMed

Park, Seok-Woo; Kim, Hyo-Sun; Choi, Myung-Sun; Kim, Ji-Eun; Jeong, Woo-Jin; Heo, Dae-Seog; Sung, Myung-Whun

2011-06-01

We have previously observed that cyclooxygenase-2 (COX-2) inhibition blocked the production of vascular endothelial growth factor (VEGF) in some head and neck squamous cell carcinoma (HNSCC) cells. However, as some HNSCC cells showed little response to COX-2 inhibition, although they highly expressed COX-2 and prostaglandin E2, we set out to elucidate what made this difference between them and focused on the possibility of the differential expression of COX-1. In western blotting, we found that COX-1 was expressed in SNU-1041 and SNU-1066, but not in SNU-1076 and PCI-50. Only in those cell lines without expression of COX-1 was VEGF production blocked meaningfully by small interfering RNA of COX-2. However, by cotreating with small interfering RNAs of COX-2 and COX-1, VEGF synthesis and prostaglandin E2 were inhibited in SNU-1041 and SNU-1066, similarly in SNU-1076 and PCI-50 with high expression of only COX-2. We also found that there was no difference in the pattern of prostaglandin synthesis between COX-2 and COX-1 through enzyme-linked immunosorbent assay for various prostaglandins. Our study suggests that, as COX-1 and COX-2 express and affect VEGF synthesis in HNSCC cells, we should check COX-1 expression in investigations on cancer treatment by inhibiting COX-2-induced prostaglandins.

Increased risk of incident stroke associated with the cyclooxygenase 2 (COX-2) G-765C polymorphism in African-Americans: the Atherosclerosis Risk in Communities Study.

PubMed

Kohsaka, Shun; Volcik, Kelly A; Folsom, Aaron R; Wu, Kenneth K; Ballantyne, Christie M; Willerson, James T; Boerwinkle, Eric

2008-02-01

A hallmark feature of atherosclerosis is inflammation mediated by prostaglandins (PGs) catalyzed by the enzyme cyclooxygenase (COX). The present study explored whether the COX-2 G-765C polymorphism contributes to increased incidence of coronary heart disease (CHD) or stroke in the large prospective Atherosclerosis Risk in Communities (ARIC) Study. Incidences of CHD and stroke were identified through annual follow-up and hospital and death certificate surveillance. The study included 1488 incident CHD and 527 stroke events after an average of 14 years of follow-up. The frequency of the -765C variant allele was markedly different between African-Americans and whites, therefore all analyses were performed separately by race. Due to the small number of persons with the -765CC genotype, heterozygous and homozygous variant genotypes were combined for this analysis. The COX-2 G-765C polymorphism was not a significant predictor of CHD in either racial group, but it was a significant predictor of incident stroke in African-Americans. After adjustment for age and gender, the hazard rate ratio for developing stroke for the CG+CC genotypes relative to the GG genotype was 1.34 (95% confidence interval [CI] 1.03-1.74, P=0.03) in African-Americans. This result was essentially unchanged when established predictors such as smoking, diabetes and hypertension were added to the model (HRR 1.34, 95%CI 1.03-1.76, P=0.03). We have found the COX-2 G-765C polymorphism to be a risk factor for incident stroke in African-Americans. This study provides additional evidence for utilizing inflammation-related genetic polymorphisms for identifying individuals at increased risk for stroke.

COX-1 vs. COX-2 as a determinant of basal tone in the internal anal sphincter

PubMed Central

de Godoy, Márcio A. F.; Rattan, Neeru; Rattan, Satish

2009-01-01

Prostanoids, produced endogenously via cyclooxygenases (COXs), have been implicated in the sustained contraction of different smooth muscles. The two major types of COXs are COX-1 and COX-2. The COX subtype involved in the basal state of the internal anal sphincter (IAS) smooth muscle tone is not known. To identify the COX subtype, we examined the effect of COX-1- and COX-2-selective inhibitors, SC-560 and rofecoxib, respectively, on basal tone in the rat IAS. We also determined the effect of selective deletion of COX-1 and COX-2 genes (COX-1−/− and COX-2−/− mice) on basal tone in murine IAS. Our data show that SC-560 causes significantly more efficacious and potent concentration-dependent decreases in IAS tone than rofecoxib. In support of these data, significantly higher levels of COX-1 than COX-2 mRNA were found in the IAS. In addition, higher levels of COX-1 mRNA and protein were expressed in rat IAS than rectal smooth muscle. In wild-type mice, IAS tone was decreased 41.4 ± 3.4% (mean ± SE) by SC-560 (1 × 10−5 M) and 5.4 ± 2.2% by rofecoxib (P < 0.05, n = 5). Basal tone was 0.172 ± 0.021 mN//mg in the IAS from wild-type mice and significantly less (0.080 ± 0.015 mN/mg) in the IAS from COX-1−/− mice (P < 0.05, n = 5). However, basal tone in COX-2−/− mice was not significantly different from that in wild-type mice. We conclude that COX-1-related products contribute significantly to IAS tone. PMID:19056763

Preferential Cyclooxygenase 2 Inhibitors as a Nonhormonal Method of Emergency Contraception: A Look at the Evidence.

PubMed

Weiss, Erich A; Gandhi, Mona

2016-04-01

To review the literature surrounding the use of preferential cyclooxygenase 2 (COX-2) inhibitors as an alternative form of emergency contraception. MEDLINE (1950 to February 2014) was searched using the key words cyclooxygenase or COX-2 combined with contraception, emergency contraception, or ovulation. Results were limited to randomized control trials, controlled clinical trials, and clinical trials. Human trials that measured the effects of COX inhibition on female reproductive potential were included for review. The effects of the COX-2 inhibitors rofecoxib, celecoxib, and meloxicam were evaluated in 6 trials. Each of which was small in scope, enrolled women of variable fertility status, used different dosing regimens, included multiple end points, and had variable results. Insufficient evidence exists to fully support the use of preferential COX-2 inhibitors as a form of emergency contraception. Although all trials resulted in a decrease in ovulatory cycles, outcomes varied between dosing strategies and agents used. A lack of homogeneity in these studies makes comparisons difficult. However, success of meloxicam in multiple trials warrants further study. Larger human trials are necessary before the clinical utility of this method of emergency contraception can be fully appreciated. © The Author(s) 2014.

Cyclooxygenase-2 inhibitors. Synthesis and pharmacological activities of 5-methanesulfonamido-1-indanone derivatives.

PubMed

Li, C S; Black, W C; Chan, C C; Ford-Hutchinson, A W; Gauthier, J Y; Gordon, R; Guay, D; Kargman, S; Lau, C K; Mancini, J

1995-12-08

The recent discovery of an alternative form cyclooxygenase (cyclooxygenase-2, COX-2), which has been proposed to play a significant role in inflammatory conditions, may provide an opportunity to develop anti-inflammatory drugs with fewer side effects than existing non-steroidal anti-inflammatory drugs (NSAIDs). We have now identified 6-[(2,4-difluorophenyl)-thio]-5-methanesulfonamido-1-indanone++ + (20) (L-745,337) as a potent, selective, and orally active COX-2 inhibitor. The structure-activity relationships in this series have been extensively studied. Ortho- and para-substituted 6-phenyl substitutents are optimal for in vitro potency. Replacement of this phenyl ring by a variety of heterocycles gave compounds that were less active. The methanesulfonamido group seems to be the optimal group at the 5-position of the indanone system. Compound 20 has an efficacy profile that is superior or comparable to that of the nonselective COX inhibitor indomethacin in animal models of inflammation, pain, and fever and appears to be nonulcerogenic within the dosage ranges required for functional efficacy. Although 20 and its oxygen linkage analog 2 (flosulide) are equipotent in the in vitro assays, compound 20 is more potent in the rat paw edema assay, has a longer t1/2 in squirrel monkeys, and seems less ulcergenic than 2 in rats.

COX-2 expression and outcome in canine nasal carcinomas treated with hypofractionated radiotherapy.

PubMed

Belshaw, Z; Constantio-Casas, F; Brearley, M J; Dunning, M D; Holmes, M A; Dobson, J M

2011-06-01

The expression of cyclooxygenase isoform 2 (COX-2) in canine nasal carcinomas has been well documented. COX-2 expression has proven to be a prognostic factor in several human tumours. The aims of this study were to assess the correlation between immunohistochemical COX-2 expression and prognosis using rhinoscopic biopsies from 42 dogs with nasal carcinomas treated with hypofractionated radiotherapy, and to establish a replicable COX-2 scoring system. Ninety per cent of sections evaluated were COX-2 positive with a mean score of 6.6 (median 8.0; range 0-12). Neither COX-2 expression nor tumour type had a significant correlation with survival. There are likely to be many as yet unidentified variants which contribute to length of survival in dogs with nasal carcinomas. Immunohistochemical COX-2 expression appears unlikely to be of prognostic significance for canine nasal carcinoma. © 2010 Blackwell Publishing Ltd.

Expression of vitamin D receptor (VDR), cyclooxygenase-2 (COX-2) and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in benign and malignant ovarian tissue and 25-hydroxycholecalciferol (25(OH2)D3) and prostaglandin E2 (PGE2) serum level in ovarian cancer patients.

PubMed

Thill, Marc; Fischer, Dorothea; Kelling, Katharina; Hoellen, Friederike; Dittmer, Christine; Hornemann, Amadeus; Salehin, Darius; Diedrich, Klaus; Friedrich, Michael; Becker, Steffi

2010-07-01

Ovarian carcinomas are associated with increased inflammation which is based upon an up-regulation of inducible cyclooxygenase-2 (COX-2). Moreover, based on our previous published data, the extra-renal vitamin D metabolism seems to be dysregulated in comparison to healthy tissue. In order to gain further insight into the prostaglandin (PG)- and vitamin D-metabolism in ovarian carcinomas, the study aimed to evaluate the expression of the PG metabolising enzymes COX-2 and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) compared to the vitamin D receptor (VDR) in benign and malignant ovarian tissues. Additionally, we determined the 25-hydroxycholecalciferol (25(OH2)D3) serum levels. Expression of VDR, COX-2 and 15-PGDH was determined by Western blot analysis. Serum levels of 25(OH2)D3 and PGE2 were measured by chemiluminescence-based and colorimetric immunoassay. We detected significantly higher expressions of the PG metabolising enzymes 15-PGDH and COX-2 in malignant tissue and PGE2 serum levels were 2-fold higher in tumour patients. Furthermore, we found an inverse correlation to the VDR-expression which was 62.1% lower in malignant tissues compared to that in benign tissues. Surprisingly, we could not detect any differences between the 25(OH2)D3 serum levels in either group (n=20). These data suggest a correlation between PG- and vitamin D-metabolism in ovarian carcinomas. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Cannabidiolic acid as a selective cyclooxygenase-2 inhibitory component in cannabis.

PubMed

Takeda, Shuso; Misawa, Koichiro; Yamamoto, Ikuo; Watanabe, Kazuhito

2008-09-01

In the present study it was revealed that cannabidiolic acid (CBDA) selectively inhibited cyclooxygenase (COX)-2 activity with an IC(50) value (50% inhibition concentration) around 2 microM, having 9-fold higher selectivity than COX-1 inhibition. In contrast, Delta(9)-tetrahydrocannabinolic acid (Delta(9)-THCA) was a much less potent inhibitor of COX-2 (IC(50) > 100 microM). Nonsteroidal anti-inflammatory drugs containing a carboxyl group in their chemical structures such as salicylic acid are known to inhibit nonselectively both COX-1 and COX-2. CBDA and Delta(9)-THCA have a salicylic acid moiety in their structures. Thus, the structural requirements for the CBDA-mediated COX-2 inhibition were next studied. There is a structural difference between CBDA and Delta(9)-THCA; phenolic hydroxyl groups of CBDA are freed from the ring formation with the terpene moiety, although Delta(9)-THCA has dibenzopyran ring structure. It was assumed that the whole structure of CBDA is important for COX-2 selective inhibition because beta-resorcylic acid itself did not inhibit COX-2 activity. Methylation of the carboxylic acid moiety of CBDA led to disappearance of COX-2 selectivity. Thus, it was suggested that the carboxylic acid moiety in CBDA is a key determinant for the inhibition. Furthermore, the crude extract of cannabis containing mainly CBDA was shown to have a selective inhibitory effect on COX-2. Taken together, these lines of evidence in this study suggest that naturally occurring CBDA in cannabis is a selective inhibitor for COX-2.

Use of cyclo-oxygenase 2 inhibitors (COX-2) and prescription non-steroidal anti-inflammatory drugs (NSAIDS) in UK and USA populations. Implications for COX-2 cardiovascular profile.

PubMed

Arellano, Félix M; Yood, Marianne Ulcickas; Wentworth, Charles E; Oliveria, Susan A; Rivero, Elena; Verma, Anila; Rothman, Kenneth J

2006-12-01

COX-2 and NSAIDS differ in their gastrointestinal (GI) and cardiovascular (CV) toxicity from pharmacological, clinical and epidemiologic point of views. Describe the patterns of use of NSAIDS and COX-2 in The Health Improvement Network (THIN) database in UK and the PharMetrics database in USA. We examined the experience of 10 distinct cohorts of new users of diclofenac, naproxen, ibuprofen, piroxicam, other NSAIDS, meloxicam, celecoxib, etoricoxib, rofecoxib and valdecoxib. The study period was 1 January 1995 through 2004 (31 March in UK and 28 February in USA). We collected information on covariates including history of upper GI disease, CV disease, hepatic disease, dosage, concomitant medication, and visits to a rheumatologist. We identified 486 076 unique patient-drug pairs in UK and 1 533 239 in USA. In UK population 78 201 (16%) were COX-2 users and in PharMetrics 324 206 (21%) were COX-2 users. Diclofenac and ibuprofen (NSAIDS), and celecoxib and rofecoxib (COX-2) were the agents prescribed most frequently. The duration of therapy was longer among celecoxib and rofecoxib users than among other users. More COX-2 users than NSAIDS users received concomitant gastroprotective agents (GPA), corticosteroids and anti-platelet therapy, and had a history of thromboembolic events and hypertension. PharMetrics patients were prescribed higher doses of NSAIDS and COX-2. The use of any single agent for more than 90 days was uncommon, but more frequent in PharMetrics. Switching was uncommon and was generally to a NSAID. Our results confirm some previous findings from other authors such as the presence of both GI and CV channelling to COX-2 agents but refute others, such as the frequency of drug switching between these agents. The typical use of COX-2 agents in practice is for shorter duration, and at lower doses, than was employed in randomized clinical trials. This difference may help clarify the apparent discrepancy with respect to CV toxicity between the results from

Gender differences in hypoxic acclimatization in cyclooxygenase-2-deficient mice.

PubMed

Xu, Kui; Sun, Xiaoyan; Benderro, Girriso F; Tsipis, Constantinos P; LaManna, Joseph C

2017-02-01

The aim of this study was to determine the effect of cyclooxygenase-2 (COX-2) gene deletion on the adaptive responses during prolonged moderate hypobaric hypoxia. Wild-type (WT) and COX-2 knockout (KO) mice of both genders (3 months old) were exposed to hypobaric hypoxia (~0.4 ATM) or normoxia for 21 days and brain capillary densities were determined. Hematocrit was measured at different time intervals; brain hypoxia-inducible factor -1 α (HIF-1 α ), angiopoietin 2 (Ang-2), brain erythropoietin (EPO), and kidney EPO were measured under normoxic and hypoxic conditions. There were no gender differences in hypoxic acclimatization in the WT mice and similar adaptive responses were observed in the female KO mice. However, the male KO mice exhibited progressive vulnerability to prolonged hypoxia. Compared to the WT and female KO mice, the male COX-2 KO mice had significantly lower survival rate and decreased erythropoietic and polycythemic responses, diminished cerebral angiogenesis, decreased brain accumulation of HIF-1 α , and attenuated upregulation of VEGF, EPO, and Ang-2 during hypoxia. Our data suggest that there are physiologically important gender differences in hypoxic acclimatization in COX-2-deficient mice. The COX-2 signaling pathway appears to be required for acclimatization in oxygen-limiting environments only in males, whereas female COX-2-deficient mice may be able to access COX-2-independent mechanisms to achieve hypoxic acclimatization. © 2017 Case Western Reserve University. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Cyclooxygenase-1 and -2 Play Contrasting Roles in Listeria-Stimulated Immunity.

PubMed

Theisen, Erin; McDougal, Courtney E; Nakanishi, Masako; Stevenson, David M; Amador-Noguez, Daniel; Rosenberg, Daniel W; Knoll, Laura J; Sauer, John-Demian

2018-06-01

Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) activity and are commonly used for pain relief and fever reduction. NSAIDs are used following childhood vaccinations and cancer immunotherapies; however, how NSAIDs influence the development of immunity following these therapies is unknown. We hypothesized that NSAIDs would modulate the development of an immune response to Listeria monocytogenes -based immunotherapy. Treatment of mice with the nonspecific COX inhibitor indomethacin impaired the generation of cell-mediated immunity. This phenotype was due to inhibition of the inducible COX-2 enzyme, as treatment with the COX-2-selective inhibitor celecoxib similarly inhibited the development of immunity. In contrast, loss of COX-1 activity improved immunity to L. monocytogenes Impairments in immunity were independent of bacterial burden, dendritic cell costimulation, or innate immune cell infiltrate. Instead, we observed that PGE 2 production following L. monocytogenes is critical for the formation of an Ag-specific CD8 + T cell response. Use of the alternative analgesic acetaminophen did not impair immunity. Taken together, our results suggest that COX-2 is necessary for optimal CD8 + T cell responses to L. monocytogenes , whereas COX-1 is detrimental. Use of pharmacotherapies that spare COX-2 activity and the production of PGE 2 like acetaminophen will be critical for the generation of optimal antitumor responses using L. monocytogenes . Copyright © 2018 by The American Association of Immunologists, Inc.

The transcription factor c-Fos coordinates with histone lysine-specific demethylase 2A to activate the expression of cyclooxygenase-2

PubMed Central

Du, Yipeng; Cao, Lin-lin; Li, Meiting; Shen, Changchun; Hou, Tianyun; Zhao, Ying; Wang, Haiying; Deng, Dajun; Wang, Lina; He, Qihua; Zhu, Wei-Guo

2015-01-01

Cyclooxygenase-2 (COX-2) is overexpressed in a variety of human epithelial cancers, including lung cancer, and is highly associated with a poor prognosis and a low survival rate. Understanding how COX-2 is regulated in response to carcinogens will offer insight into designing anti-cancer strategies and preventing cancer development. Here, we analyzed COX-2 expression in several human lung cancer cell lines and found that COX-2 expression was absent in the H719 and H460 cell lines by a DNA methylation-independent mechanism. The re-expression of COX-2 was observed after 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment in both cell lines. Further investigation found that H3K36 dimethylation was significantly reduced near the COX-2 promoter because histone demethylase 2A (KDM2A) was recruited to the COX-2 promoter after TPA treatment. In addition, the transcription factor c-Fos was found to be required to recruit KDM2A to the COX-2 promoter for reactivation of COX-2 in response to TPA treatment in both the H719 and H460 cell lines. Together, our data reveal a novel mechanism by which the carcinogen TPA activates COX-2 expression by regulating H3K36 dimethylation near the COX-2 promoter. PMID:26430963

Parecoxib Increases Blood Pressure Through Inhibition of Cyclooxygenase-2 Messenger RNA in an Experimental Model.

PubMed

Vértiz-Hernández, Ángel Antonio; Martínez-Morales, Flavio; Valle-Aguilera, Roberto; López-Sánchez, Pedro; Villalobos-Molina, Rafael; Pérez-Urizar, José

2015-01-01

Cyclooxygenase-2 selective inhibitors have been developed to alleviate pain and inflammation; however, the use of a selective cyclooxygenase-2 inhibitor is associated with mild edema, hypertension, and cardiovascular risk. To evaluate, in an experimental model in normotensive rats, the effect of treatment with parecoxib in comparison with diclofenac and aspirin and L-NAME, a non-selective nitric oxide synthetase, on mean arterial blood pressure, and cyclooxygenase-1 and -2 messenger RNA and protein expression in aortic tissue. Rats were treated for seven days with parecoxib (10 mg/kg/day), diclofenac (3.2 mg/kg/day), aspirin (10 mg/kg/day), or L-NAME (10 mg/kg/day). Mean arterial blood pressure was evaluated in rat tail; cyclooxygenase-1 and -2 were evaluated by reverse transcription-polymerase chain reaction and Western blot analysis in aortic tissue. Parecoxib and L-NAME, but not aspirin and diclofenac, increased mean arterial blood pressure by about 50% (p < 0.05) without changes in cardiac frequency. Messenger RNA cyclooxygenase-1 expression in aortic tissue was not modified with any drug (p < 0.05). L-NAME and parecoxib treatment decreased messenger RNA cyclooxygenase-2 and cyclooxygenase-2 (p < 0.05). While cyclooxygenase-1 protein decreased with the three drugs tested but not with L-NAME (p < 0.05), the cyclooxygenase-2 protein decreased only with aspirin and parecoxib (p < 0.05). Parecoxib increases the blood pressure of normotensive rats by the suppression of COX-2 gene expression, which apparently induced cardiovascular control.

The Molecular Basis for Dual Fatty Acid Amide Hydrolase (FAAH)/Cyclooxygenase (COX) Inhibition.

PubMed

Palermo, Giulia; Favia, Angelo D; Convertino, Marino; De Vivo, Marco

2016-06-20

The design of multitarget-directed ligands is a promising strategy for discovering innovative drugs. Here, we report a mechanistic study that clarifies key aspects of the dual inhibition of the fatty acid amide hydrolase (FAAH) and the cyclooxygenase (COX) enzymes by a new multitarget-directed ligand named ARN2508 (2-[3-fluoro-4-[3-(hexylcarbamoyloxy)phenyl]phenyl]propanoic acid). This potent dual inhibitor combines, in a single scaffold, the pharmacophoric elements often needed to block FAAH and COX, that is, a carbamate moiety and the 2-arylpropionic acid functionality, respectively. Molecular modeling and molecular dynamics simulations suggest that ARN2508 uses a noncovalent mechanism of inhibition to block COXs, while inhibiting FAAH via the acetylation of the catalytic Ser241, in line with previous experimental evidence for covalent FAAH inhibition. This study proposes the molecular basis for the dual FAAH/COX inhibition by this novel hybrid scaffold, stimulating further experimental studies and offering new insights for the rational design of novel anti-inflammatory agents that simultaneously act on FAAH and COX. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Tangeretin suppresses IL-1beta-induced cyclooxygenase (COX)-2 expression through inhibition of p38 MAPK, JNK, and AKT activation in human lung carcinoma cells.

PubMed

Chen, Kuan-Hung; Weng, Meng-Shih; Lin, Jen-Kun

2007-01-15

Tangeretin (5,6,7,8,4'-pentamethoxyflavone) is a polymethoxylated flavonoid concentrated in the peel of citrus fruits. Recent studies have shown that tangeretin exhibits anti-proliferative, anti-invasive, anti-metastatic, and antioxidant activities. However, the anti-inflammatory properties of tangeretin are unclear. In this study, we examine the effects of tangeretin and its structure-related compound, nobiletin, on the expression of cyclooxygenases-2 (COX-2) in human lung epithelial carcinoma cells, A549, and human non-small cell lung carcinoma cells, H1299. Tangeretin exerts a much better inhibitory activity than nobiletin against IL-1beta-induced production of COX-2 in A549 cells, and it effectively represses the constitutively expressed COX-2 in H1299. RT-PCR was used to investigate the transcriptional inhibition of COX-2 by tangeretin. COX-2 mRNA was rapidly induced by IL-1beta in 3h and markedly suppressed by tangeretin. IL-1beta-induced the activation of ERK, p38 MAPK, JNK, and AKT in A549 cells. COX-2 expression in response to IL-1beta was attenuated by pretreatment with SB203580, SP600125, and LY294002, but not with PD98059, suggesting the involvement of p38 MAPK, JNK, and PI3K in this response. Pretreatment of cells with tangeretin inhibited IL-1beta-induced p38 MAPK, JNK, and AKT phosphorylation and the downstream activation of NF-kappaB. These results may reveal that the tangeretin inhibition of IL-1beta-induced COX-2 expression in A549 cells is, at least in part, mediated through suppression of NF-kappaB transcription factor as well as through suppression of the signaling proteins of p38 MAPK, JNK, and PI3K, but not of ERK.

Targeted imaging of cancer by fluorocoxib C, a near-infrared cyclooxygenase-2 probe

NASA Astrophysics Data System (ADS)

Uddin, Md. Jashim; Crews, Brenda C.; Ghebreselasie, Kebreab; Daniel, Cristina K.; Kingsley, Philip J.; Xu, Shu; Marnett, Lawrence J.

2015-05-01

Cyclooxygenase-2 (COX-2) is a promising target for the imaging of cancer in a range of diagnostic and therapeutic settings. We report a near-infrared COX-2-targeted probe, fluorocoxib C (FC), for visualization of solid tumors by optical imaging. FC exhibits selective and potent COX-2 inhibition in both purified protein and human cancer cell lines. In vivo optical imaging shows selective accumulation of FC in COX-2-overexpressing human tumor xenografts [1483 head and neck squamous cell carcinoma (HNSCC)] implanted in nude mice, while minimal uptake is detectable in COX-2-negative tumor xenografts (HCT116) or 1483 HNSCC xenografts preblocked with the COX-2-selective inhibitor celecoxib. Time course imaging studies conducted from 3 h to 7-day post-FC injection revealed a marked reduction in nonspecific fluorescent signals with retention of fluorescence in 1483 HNSCC tumors. Thus, use of FC in a delayed imaging protocol offers an approach to improve imaging signal-to-noise that should improve cancer detection in multiple preclinical and clinical settings.

Prevention of posterior capsular opacification through cyclooxygenase-2 inhibition

PubMed Central

Barden, Curtis A; Lu, Ping; Kusewitt, Donna F.; Colitz, Carmen M. H.

2007-01-01

Purpose To determine if cyclooxygenase-2 (COX-2) is upregulated when lens epithelial cells (LEC) in clinical samples of cataracts and posterior capsule opacification (PCO) undergo epithelial-mesenchymal transition (EMT)-like changes. We also wanted to learn if inhibition of the enzymatic activity of COX-2 could prevent PCO formation. Methods To ensure that EMT-like changes were occurring in LEC, real-time RT-PCR was used to examine expression of EMT markers. Clinical samples of canine cataracts and PCO were examined for COX-2 expression using immunohistochemistry, western blot analysis, and real-time RT-PCR. The COX-2 inhibitors, rofecoxib and celecoxib, were used in an ex vivo model of PCO formation, and the effects on cellular migration, proliferation, and apoptosis were analyzed using immunohistochemistry and western blots. Prostaglandin E2 (PGE2) expression was examined with ELISA. Results Markers of EMT, such as lumican, Snail, Slug, and COX-2 were expressed in LEC. In clinical samples of cataracts and PCO, there was overexpression of COX-2 protein and mRNA. Both rofecoxib and celecoxib were effective at inhibiting PCO formation in our ex vivo model. Prevention of PCO with the COX-2 inhibitors appeared to work through decreased migration and proliferation, and increased apoptosis. Neither of the drugs had a toxic effect on confluent LEC and appeared to inhibit PCO through their pharmacologic action. Synthesis of PGE2 was inhibiting in the capsules treated with the COX-2 inhibiting drugs. Conclusions Extracapsular phacoemulsification cataract surgery is the most common surgical procedure performed in human and veterinary ophthalmology. The most frequent postoperative complication is PCO. The LEC that remain adhered to the lens capsule undergo EMT-like changes, proliferate, and migrate across the posterior lens capsule causing opacities. We have shown that COX-2, a protein associated with EMT, is upregulated in canine cataracts and PCO. Inhibiting the enzymatic

Elevated interleukin 6 is induced by prostaglandin E2 in a murine model of inflammation: possible role of cyclooxygenase-2.

PubMed Central

Hinson, R M; Williams, J A; Shacter, E

1996-01-01

Injection of mineral oils such as pristane into the peritoneal cavities of BALB/c mice results in a chronic peritonitis associated with high tissue levels of interleukin 6 (IL-6). Here we show that increased prostaglandin E2 (PGE2) synthesis causes induction of IL-6 and that expression of an inducible cyclooxygenase, Cox-2, may mediate this process. Levels of both PGE2 and IL-6 are elevated in inflammatory exudates from pristane-treated mice compared with lavage samples from untreated mice. The Cox-2 gene is induced in the peritoneal macrophage fraction isolated from the mice. A cause and effect relationship between increased macrophage PGE2 and IL-6 production is shown in vitro. When peritoneal macrophages are activated with an inflammatory stimulus (polymerized albumin), the Cox-2 gene is induced and secretion of PGE2 and IL-6 increases, with elevated PGE2 appearing before IL-6. Cotreatment with 1 microM indomethacin inhibits PGE2 production by the cells and reduces the induction of IL-6 mRNA but has no effect on Cox-2 mRNA, consistent with the fact that the drug inhibits catalytic activity of the cyclooxygenase but does not affect expression of the gene. Addition of exogenous PGE2 to macrophages induces IL-6 protein and mRNA synthesis, indicating that the eicosanoid stimulates IL-6 production at the level of gene expression. PGE2-stimulated IL-6 production is unaffected by addition of indomethacin. Taken together with the earlier finding that indomethacin diminishes the elevation of IL-6 in pristane-treated mice, the results show that PGE2 can induce IL-6 production in vivo and implicate expression of the Cox-2 gene in the regulation of this cytokine. Images Fig. 2 Fig. 4 Fig. 5 Fig. 6 Fig. 8 PMID:8643498

Smad3 mutant mice develop colon cancer with overexpression of COX-2

PubMed Central

Zhu, Yu-Ping; Liu, Zhuo; Fu, Zhi-Xuan; Li, De-Chuan

2017-01-01

Colon cancer is the second most common cause of cancer-associated mortality in human populations. The aim of the present study was to identify the role of cyclooxygenase-2 (COX-2) in Smad3 mutant mice, which are known to develop colon cancer. Homozygous Smad3 (−/−) mutant mice were generated from inbred and hybrid Smad3 mouse strains by intercrossing the appropriate heterozygotes. Immunohistochemistry with COX-2 antibody was performed throughout this experiment and the data was validated and cross-checked with reverse transcription-polymerase chain reaction (RT-PCR). Homozygous mutant Smad3 mice were generated and the overexpression pattern of COX-2 was identified by immunohistochemistry and validated with RT-PCR. The results of the present study demonstrated a link between the Smad3 mutant mice, colon cancer and COX-2. In addition, the overexpression pattern of COX-2 in Smad3 mutant mice that develop colon cancer was identified. PMID:28454287

Influenza A viruses suppress cyclooxygenase-2 expression by affecting its mRNA stability.

PubMed

Dudek, Sabine Eva; Nitzsche, Katja; Ludwig, Stephan; Ehrhardt, Christina

2016-06-06

Infection with influenza A viruses (IAV) provokes activation of cellular defence mechanisms contributing to the innate immune and inflammatory response. In this process the cyclooxygenase-2 (COX-2) plays an important role in the induction of prostaglandin-dependent inflammation. While it has been reported that COX-2 is induced upon IAV infection, in the present study we observed a down-regulation at later stages of infection suggesting a tight regulation of COX-2 by IAV. Our data indicate the pattern-recognition receptor RIG-I as mediator of the initial IAV-induced COX-2 synthesis. Nonetheless, during on-going IAV replication substantial suppression of COX-2 mRNA and protein synthesis could be detected, accompanied by a decrease in mRNA half-life. Interestingly, COX-2 mRNA stability was not only imbalanced by IAV replication but also by stimulation of cells with viral RNA. Our results reveal tristetraprolin (TTP), which is known to bind COX-2 mRNA and promote its rapid degradation, as regulator of COX-2 expression in IAV infection. During IAV replication and viral RNA accumulation TTP mRNA synthesis was induced, resulting in reduced COX-2 levels. Accordingly, the down-regulation of TTP resulted in increased COX-2 protein expression after IAV infection. These findings indicate a novel IAV-regulated cellular mechanism, contributing to the repression of host defence and therefore facilitating viral replication.

Indoleamine-2,3-dioxygenase 1/cyclooxygenase 2 expression prediction for adverse prognosis in colorectal cancer

PubMed Central

Ma, Wen-Juan; Wang, Xing; Yan, Wen-Ting; Zhou, Zhong-Guo; Pan, Zhi-Zhong; Chen, Gong; Zhang, Rong-Xin

2018-01-01

AIM To evaluate indoleamine-2,3-dioxygenase 1/cyclooxygenase 2 (IDO1/COX2) expression as an independent prognostic biomarker for colorectal cancer (CRC) patients. METHODS We retrospectively studied the medical records of 95 patients who received surgical resection from August 2008 to January 2010. All patients were randomly assigned to adjuvant treatment with or without celecoxib groups after surgery. We performed standard immunohistochemistry to assess the expression levels of IDO1/COX2 and evaluated the correlation of IDO1/COX2 with clinicopathological factors and overall survival (OS) outcomes. RESULTS The expression of nuclear IDO1 was significantly correlated with body mass index (P < 0.001), and IDO1 expression displayed no association with sex, age, tumor differentiation, T stage, N stage, carcinoembryonic antigen, cancer antigen 19-9, CD3+ and CD8+ tumor infiltrating lymphocytes, and COX2. In univariate analysis, we found that nuclear IDO1 (P = 0.039), nuclear/cytoplasmic IDO1 [hazard ratio (HR) = 2.044, 95% confidence interval (CI): 0.871-4.798, P = 0.039], nuclear IDO1/COX2 (HR = 3.048, 95%CI: 0.868-10.7, P = 0.0049) and cytoplasmic IDO1/COX2 (HR = 2.109, 95%CI: 0.976-4.558, P = 0.022) all yielded significantly poor OS outcomes. Nuclear IDO1 (P = 0.041), nuclear/cytoplasmic IDO1 (HR = 3.023, 95%CI: 0.585-15.61, P = 0.041) and cytoplasmic IDO1/COX2 (HR = 2.740, 95%CI: 0.764-9.831, P = 0.038) have significantly poor OS outcomes for the CRC celecoxib subgroup. In our multivariate Cox model, high coexpression of cytoplasmic IDO1/COX2 was found to be an independent predictor of poor outcome in CRC (HR = 2.218, 95%CI: 1.011-4.48, P = 0.047) and celecoxib subgroup patients (HR = 3.210, 95%CI: 1.074-9.590, P = 0.037). CONCLUSION Our results showed that cytoplasmic IDO1/COX2 coexpression could be used as an independent poor predictor for OS in CRC. PMID:29853736

Reactive astrocyte COX2-PGE2 production inhibits oligodendrocyte maturation in neonatal white matter injury.

PubMed

Shiow, Lawrence R; Favrais, Geraldine; Schirmer, Lucas; Schang, Anne-Laure; Cipriani, Sara; Andres, Christian; Wright, Jaclyn N; Nobuta, Hiroko; Fleiss, Bobbi; Gressens, Pierre; Rowitch, David H

2017-12-01

Inflammation is a major risk factor for neonatal white matter injury (NWMI), which is associated with later development of cerebral palsy. Although recent studies have demonstrated maturation arrest of oligodendrocyte progenitor cells (OPCs) in NWMI, the identity of inflammatory mediators with direct effects on OPCs has been unclear. Here, we investigated downstream effects of pro-inflammatory IL-1β to induce cyclooxygenase-2 (COX2) and prostaglandin E2 (PGE2) production in white matter. First, we assessed COX2 expression in human fetal brain and term neonatal brain affected by hypoxic-ischemic encephalopathy (HIE). In the developing human brain, COX2 was expressed in radial glia, microglia, and endothelial cells. In human term neonatal HIE cases with subcortical WMI, COX2 was strongly induced in reactive astrocytes with "A2" reactivity. Next, we show that OPCs express the EP1 receptor for PGE2, and PGE2 acts directly on OPCs to block maturation in vitro. Pharmacologic blockade with EP1-specific inhibitors (ONO-8711, SC-51089), or genetic deficiency of EP1 attenuated effects of PGE2. In an IL-1β-induced model of NWMI, astrocytes also exhibit "A2" reactivity and induce COX2. Furthermore, in vivo inhibition of COX2 with Nimesulide rescues hypomyelination and behavioral impairment. These findings suggest that neonatal white matter astrocytes can develop "A2" reactivity that contributes to OPC maturation arrest in NWMI through induction of COX2-PGE2 signaling, a pathway that can be targeted for neonatal neuroprotection. © 2017 Wiley Periodicals, Inc.

Mechanism of acetaminophen inhibition of cyclooxygenase isoforms.

PubMed

Ouellet, M; Percival, M D

2001-03-15

Acetaminophen has similar analgesic and antipyretic properties to nonsteroidal antiinflammatory drugs (NSAIDs), which act via inhibition of cyclooxygenase enzymes. However, unlike NSAIDs, acetaminophen is at best weakly antiinflammatory. The mechanism by which acetaminophen exerts its therapeutic action has yet to be fully determined, as under most circumstances, acetaminophen is a very weak cyclooxygenase inhibitor. The potency of acetaminophen against both purified ovine cyclooxygenase-1 (oCOX-1) and human cyclooxygenase-2 (hCOX-2) was increased approximately 30-fold by the presence of glutathione peroxidase and glutathione to give IC50 values of 33 microM and 980 microM, respectively. Acetaminophen was found to be a good reducing agent of both oCOX-1 and hCOX-2. The results are consistent with a mechanism of inhibition of acetaminophen in which it acts to reduce the active oxidized form of COX to the resting form. Inhibition would therefore be more effective under conditions of low peroxide concentration, consistent with the known tissue selectivity of acetaminophen.

Molecular docking analysis of known flavonoids as duel COX-2 inhibitors in the context of cancer

PubMed Central

Dash, Raju; Uddin, Mir Muhammad Nasir; Hosen, S.M. Zahid; Rahim, Zahed Bin; Dinar, Abu Mansur; Kabir, Mohammad Shah Hafez; Sultan, Ramiz Ahmed; Islam, Ashekul; Hossain, Md Kamrul

2015-01-01

Cyclooxygenase-2 (COX-2) catalyzed synthesis of prostaglandin E2 and it associates with tumor growth, infiltration, and metastasis in preclinical experiments. Known inhibitors against COX-2 exhibit toxicity. Therefore, it is of interest to screen natural compounds like flavanoids against COX-2. Molecular docking using 12 known flavanoids against COX-2 by FlexX and of ArgusLab were performed. All compounds showed a favourable binding energy of >-10 KJ/mol in FlexX and > -8 kcal/mol in ArgusLab. However, this data requires in vitro and in vivo verification for further consideration. PMID:26770028

Thrombosis Is Reduced by Inhibition of COX-1, but Unaffected by Inhibition of COX-2, in an Acute Model of Platelet Activation in the Mouse

PubMed Central

Armstrong, Paul C.; Kirkby, Nicholas S.; Zain, Zetty N.; Emerson, Michael; Mitchell, Jane A.; Warner, Timothy D.

2011-01-01

Background Clinical use of selective inhibitors of cyclooxygenase (COX)-2 appears associated with increased risk of thrombotic events. This is often hypothesised to reflect reduction in anti-thrombotic prostanoids, notably PGI2, formed by COX-2 present within endothelial cells. However, whether COX-2 is actually expressed to any significant extent within endothelial cells is controversial. Here we have tested the effects of acute inhibition of COX on platelet reactivity using a functional in vivo approach in mice. Methodology/Principal Findings A non-lethal model of platelet-driven thromboembolism in the mouse was used to assess the effects of aspirin (7 days orally as control) diclofenac (1 mg.kg−1, i.v.) and parecoxib (0.5 mg.kg−1, i.v.) on thrombus formation induced by collagen or the thromboxane (TX) A2-mimetic, U46619. The COX inhibitory profiles of the drugs were confirmed in mouse tissues ex vivo. Collagen and U46619 caused in vivo thrombus formation with the former, but not latter, sensitive to oral dosing with aspirin. Diclofenac inhibited COX-1 and COX-2 ex vivo and reduced thrombus formation in response to collagen, but not U46619. Parecoxib inhibited only COX-2 and had no effect upon thrombus formation caused by either agonist. Conclusions/Significance Inhibition of COX-1 by diclofenac or aspirin reduced thrombus formation induced by collagen, which is partly dependent upon platelet-derived TXA2, but not that induced by U46619, which is independent of platelet TXA2. These results are consistent with the model demonstrating the effects of COX-1 inhibition in platelets, but provide no support for the hypothesis that acute inhibition of COX-2 in the circulation increases thrombosis. PMID:21629780

Cancer/stroma interplay via cyclooxygenase-2 and indoleamine 2,3-dioxygenase promotes breast cancer progression.

PubMed

Chen, Jing-Yi; Li, Chien-Feng; Kuo, Cheng-Chin; Tsai, Kelvin K; Hou, Ming-Feng; Hung, Wen-Chun

2014-07-25

Expression of indoleamine 2,3-dioxygenase (IDO) in primary breast cancer increases tumor growth and metastasis. However, the clinical significance of stromal IDO and the regulation of stromal IDO are unclear. Metabolomics and enzyme-linked immunosorbent assay (ELISA) were used to study the effect of cyclooxygenase-2 (COX-2)-overexpressing breast cancer cells on IDO expression in co-cultured human breast fibroblasts. Biochemical inhibitors and short-hairpin RNA (shRNA) were used to clarify how prostaglandin E2 (PGE2) upregulates IDO expression. Associations of stromal IDO with clinicopathologic parameters were tested in tumor specimens. An orthotopic animal model was used to examine the effect of COX-2 and IDO inhibitors on tumor growth. Kynurenine, the metabolite generated by IDO, increases in the supernatant of fibroblasts co-cultured with COX-2-overexpressing breast cancer cells. PGE2 released by cancer cells upregulates IDO expression in fibroblasts through an EP4/signal transducer and activator of transcription 3 (STAT3)-dependent pathway. Conversely, fibroblast-secreted kynurenine promotes the formation of the E-cadherin/Aryl hydrocarbon receptor (AhR)/S-phase kinase-associated protein 2 (Skp2) complex, resulting in degradation of E-cadherin to increase breast cancer invasiveness. The enhancement of motility of breast cancer cells induced by co-culture with fibroblasts is suppressed by the IDO inhibitor 1-methyl-tryptophan. Pathological analysis demonstrates that upregulation of stromal IDO is a poor prognosis factor and is associated with of COX-2 overexpression. Co-expression of cancer COX-2 and stromal IDO predicts a worse disease-free and metastasis-free survival. Finally, COX-2 and IDO inhibitors inhibit tumor growth in vivo. Integration of metabolomics and molecular and pathological approaches reveals the interplay between cancer and stroma via COX-2, and IDO promotes tumor progression and predicts poor patient survival.

Salidroside suppresses solar ultraviolet-induced skin inflammation by targeting cyclooxygenase-2.

PubMed

Wu, Dan; Yuan, Ping; Ke, Changshu; Xiong, Hua; Chen, Jingwen; Guo, Jinguang; Lu, Mingmin; Ding, Yanyan; Fan, Xiaoming; Duan, Qiuhong; Shi, Fei; Zhu, Feng

2016-05-03

Solar ultraviolet (SUV) irradiation causes skin disorders such as inflammation, photoaging, and carcinogenesis. Cyclooxygenase-2 (COX-2) plays a key role in SUV-induced skin inflammation, and targeting COX-2 may be a strategy to prevent skin disorders. In this study, we found that the expression of COX-2, phosphorylation of p38 or JNKs were increased in human solar dermatitis tissues and SUV-irradiated human skin keratinocyte HaCaT cells and mouse epidermal JB6 Cl41 cells. Knocking down COX-2 inhibited the production of prostaglandin E2 (PGE2), the phosphorylation of p38 or JNKs in SUV-irradiated cells, which indicated that COX-2 is not only the key enzyme for PGs synthesis, but also an upstream regulator of p38 or JNKs after SUV irradiation. The virtual ligand screening assay was used to search for natural drugs in the Chinese Medicine Database, and indicated that salidroside might be a COX-2 inhibitor. Molecule modeling indicated that salidroside can directly bind with COX-2, which was proved by in vitro pull-down binding assay. Ex vivo studies showed that salidroside has no toxicity to cells, and inhibits the production of PGE2, phosphorylation of p38 or JNKs, and secretion of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) caused by SUV irradiation. In vivo studies demonstrated that salidroside attenuates the skin inflammation induced by SUV. In brief, our data provided the evidences for the protective role of salidroside against SUV-induced inflammation by targeting COX-2, and salidroside might be a promising drug for the treatment of SUV-induced skin inflammation.

Cyclooxygenase-2 mediates the febrile response of mice to interleukin-1beta.

PubMed

Li, S; Ballou, L R; Morham, S G; Blatteis, C M

2001-08-10

Various lines of evidence have implicated cyclooxygenase (COX)-2 as a modulator of the fever induced by the exogenous pyrogen lipopolysaccharide (LPS). Thus, treatment with specific inhibitors of COX-2 suppresses the febrile response without affecting basal body (core) temperature (T(c)). Furthermore, COX-2 gene-ablated mice are unable to develop a febrile response to intraperitoneal (i.p.) LPS, whereas their COX-1-deficient counterparts produce fevers not different from their wild-type (WT) controls. To extend the apparently critical role of COX-2 for LPS-induced fevers to fevers produced by endogenous pyrogens, we studied the thermal responses of COX-1- and COX-2 congenitally deficient mice to i.p. and intracerebroventricular (i.c.v.) injections of recombinant murine (rm) interleukin (IL)-1beta. We also assessed the effects of one selective COX-1 inhibitor, SC-560, and two selective COX-2 inhibitors, nimesulide (NIM) and dimethylfuranone (DFU), on the febrile responses of WT and COX-1(-/-) mice to LPS and rmIL-1beta, i.p. Finally, we verified the integrity of the animals' responses to PGE2, i.c.v. I.p. and i.c.v. rmIL-1beta induced similar fevers in WT and COX-1 knockout mice, but provoked no rise in the T(c)s of COX-2 null mutants. The fever produced in WT mice by i.p. LPS was not affected by SC-560, but it was attenuated and abolished by NIM and DFU, respectively, while that caused by i.p. rmIL-1beta was converted into a T(c) fall by DFU. There were no differences in the responses to i.c.v. PGE2 among the WT and COX knockout mice. These results, therefore, further support the notion that the production of PGE2 in response to pyrogens is critically dependent on COX-2 expression.

Cell-type-specific roles for COX-2 in UVB-induced skin cancer

PubMed Central

Herschman, Harvey

2014-01-01

In human tumors, and in mouse models, cyclooxygenase-2 (COX-2) levels are frequently correlated with tumor development/burden. In addition to intrinsic tumor cell expression, COX-2 is often present in fibroblasts, myofibroblasts and endothelial cells of the tumor microenvironment, and in infiltrating immune cells. Intrinsic cancer cell COX-2 expression is postulated as only one of many sources for prostanoids required for tumor promotion/progression. Although both COX-2 inhibition and global Cox-2 gene deletion ameliorate ultraviolet B (UVB)-induced SKH-1 mouse skin tumorigenesis, neither manipulation can elucidate the cell type(s) in which COX-2 expression is required for tumorigenesis; both eliminate COX-2 activity in all cells. To address this question, we created Cox-2 flox/flox mice, in which the Cox-2 gene can be eliminated in a cell-type-specific fashion by targeted Cre recombinase expression. Cox-2 deletion in skin epithelial cells of SKH-1 Cox-2 flox/flox;K14Cre + mice resulted, following UVB irradiation, in reduced skin hyperplasia and increased apoptosis. Targeted epithelial cell Cox-2 deletion also resulted in reduced tumor incidence, frequency, size and proliferation rate, altered tumor cell differentiation and reduced tumor vascularization. Moreover, Cox-2 flox/flox;K14Cre + papillomas did not progress to squamous cell carcinomas. In contrast, Cox-2 deletion in SKH-1 Cox-2 flox/flox; LysMCre + myeloid cells had no effect on UVB tumor induction. We conclude that (i) intrinsic epithelial COX-2 activity plays a major role in UVB-induced skin cancer, (ii) macrophage/myeloid COX-2 plays no role in UVB-induced skin cancer and (iii) either there may be another COX-2-dependent prostanoid source(s) that drives UVB skin tumor induction or there may exist a COX-2-independent pathway(s) to UVB-induced skin cancer. PMID:24469308

COX-2 in cancer: Gordian knot or Achilles heel?

PubMed Central

Stasinopoulos, Ioannis; Shah, Tariq; Penet, Marie-France; Krishnamachary, Balaji; Bhujwalla, Zaver M.

2013-01-01

The networks of blood and lymphatic vessels and of the extracellular matrix and their cellular and structural components, that are collectively termed the tumor microenvironment, are frequently co-opted and shaped by cancer cells to survive, invade, and form distant metastasis. With an enviable capacity to adapt to continually changing environments, cancer represents the epitome of functional chaos, a stark contrast to the hierarchical and organized differentiation processes that dictate the development and life of biological organisms. The consequences of changing landscapes such as hypoxia and acidic extracellular pH in and around tumors create a cascade of changes in multiple pathways and networks that become apparent only several years later as recurrence and metastasis. These molecular and phenotypic changes, several of which are mediated by COX-2, approach the complexities of a “Gordian Knot.” We review evidence from our studies and from literature suggesting that cyclooxygenase-2 (COX-2) biology presents a nodal point in cancer biology and an “Achilles heel” of COX-2-dependent tumors. PMID:23579438

Actinic cheilitis: epithelial expression of COX-2 and its association with mast cell tryptase and PAR-2.

PubMed

Rojas, I Gina; Martínez, Alejandra; Brethauer, Ursula; Grez, Patricia; Yefi, Roger; Luza, Sandra; Marchesani, Francisco J

2009-03-01

Cyclooxygenase-2 (COX-2) is overexpressed in various types of human malignancies, including oral cancers. Recent studies have shown that mast cell-derived protease tryptase can induce COX-2 expression by the cleavage of proteinase-activated receptor-2 (PAR-2). Actinic cheilitis (AC) is a premalignant form of lip cancer characterized by an increased density of tryptase-positive mast cells. To investigate the possible contribution of tryptase to COX-2 overexpression during early lip carcinogenesis, normal lip (n=24) and AC (n=45) biopsies were processed for COX-2, PAR-2 and tryptase detection, using RT-PCR and immunohistochemistry. Expression scores were obtained for each marker and tested for statistical significance using Mann-Whitney and Spearmann's correlation tests as well as multivariate logistic regression analysis. Increased epithelial co-expression of COX-2 and PAR-2, as well as, elevated subepithelial density of tryptase-positive mast cells were found in AC as compared to normal lip (P<0.001). COX-2 overexpression was found to be a significant predictor of AC (P<0.034, forward stepwise, Wald), and to be correlated with both tryptase-positive mast cells and PAR-2 expression (P<0.01). The results suggest that epithelial COX-2 overexpression is a key event in AC, which is associated with increased tryptase-positive mast cells and PAR-2. Therefore, tryptase may contribute to COX-2 up-regulation by epithelial PAR-2 activation during early lip carcinogenesis.

Resveratrol decreases noise-induced cyclooxygenase-2 expression in the rat cochlea.

PubMed

Seidman, Michael D; Tang, Wenxue; Bai, Venkatesh Uma; Ahmad, Nadir; Jiang, Hao; Media, Joseph; Patel, Nimisha; Rubin, Cory J; Standring, Robert T

2013-05-01

Our previous studies have demonstrated the efficacy of resveratrol, a grape constituent noted for its antioxidant and anti-inflammatory properties, in reducing temporary threshold shifts and decreasing cochlear hair cell damage following noise exposure. This study was designed to identify the potential protective mechanism of resveratrol by measuring its effect on cyclooxygenase-2 (COX-2) protein expression and reactive oxygen species (ROS) formation following noise exposure. Controlled animal intervention study. Otology Laboratory, Henry Ford Health System. Twenty-two healthy male Fischer 344 rats (2-3 months old) were exposed to acoustic trauma of variable duration with or without intervention. An additional 20 healthy male rats were used to study COX-2 expression at different time points during and following treatment of 24 hours of noise exposure. Cochlear harvest was performed at various time intervals for measurement of COX-2 protein expression via Western blot analysis and immunostaining. Peripheral blood was also obtained for ROS analysis using flow cytometry. Acoustic trauma exposure resulted in a progressive up-regulation of COX-2 protein expression, commencing at 8 hours and peaking at 32 hours. Similarly, ROS production increased after noise exposure. However, treatment with resveratrol reduced noise-induced COX-2 expression as well as ROS formation in the blood as compared with the controls. COX-2 levels are induced dramatically following noise exposure. This increased expression may be a potential mechanism of noise-induced hearing loss (NIHL) and a possible mechanism of resveratrol's ability to mitigate NIHL by its ability to reduce COX-2 expression.

Preserved heart function and maintained response to cardiac stresses in a genetic model of cardiomyocyte-targeted deficiency of cyclooxygenase-2

PubMed Central

Papanicolaou, Kyriakos N.; Streicher, John M.; Ishikawa, Tomo-o; Herschman, Harvey; Wang, Yibin; Walsh, Kenneth

2010-01-01

Cyclooxygenase-1 and -2 are rate-limiting enzymes in the formation of a wide array of bioactive lipid mediators collectively known as prostanoids (prostaglandins, prostacyclins, thromboxanes). Evidence from clinical trials shows that selective inhibition of the second isoenzyme (cyclooxygenase-2, or Cox-2) is associated with increased risk for serious cardiovascular events and findings from animal-based studies have suggested protective roles of Cox-2 for the heart. To further characterize the function of Cox-2 in the heart, mice with loxP sites flanking exons 4 and 5 of Cox-2 were rendered knockout specifically in cardiac myocytes (Cox-2 CKO mice) via cre-mediated recombination. Baseline cardiac performance of CKO mice remained unchanged and closely resembled that of control mice. Furthermore, myocardial infarct size induced after in vivo ischemia/reperfusion (I/R) injury was comparable between CKO and control mice. In addition, cardiac hypertrophy and function four weeks after transverse aortic constriction (TAC) was found to be similar between the two groups. Assessment of Cox-2 expression in purified adult cardiac cells isolated after I/R and TAC suggests that the dominant source of Cox-2 is found in the non-myocyte fraction. In conclusion, our animal-based analyses together with the cell-based observations portray a limited role of cardiomyocyte-produced Cox-2 at baseline and in the context of ischemic or hemodynamic challenge. PMID:20399788

Inhibition of cyclooxygenase-2-dependent survivin mediates decursin-induced apoptosis in human KBM-5 myeloid leukemia cells

PubMed Central

Ahn, Quein; Jeong, Soo-Jin; Lee, Hyo-Jung; Kwon, Hee-Young; Han, Ihn; Kim, Hyun Seok; Lee, Hyo-Jeong; Lee, Eun-Ok; Ahn, Kwang Seok; Jung, Min-Hyung; Zhu, Shudong; Chen, Chang-Yan; Kim, Sung-Hoon

2013-01-01

We demonstrate that decursin induces apoptosis via regulation of cyclooxygenase-2 (COX-2) and survivin in leukemic KBM-5 cells. By activating an apoptotic machinery, decursin is cytotoxic to KBM-5 cells. In this apoptotic process, decursin can activate caspase family members and triggers PARP cleavage. At the same time, the expression of COX-2 and survivin in the cells is downregulated. Furthermore, decursin is in synergy with COX-2 inhibitor, celecoxib or NS398 for the induction of apoptosis. Overall, these results suggest that decursin, via inhibiting COX-2 and survivin, sensitizes human leukemia cells to apoptosis and is a potential chemotherapeutic agent to treat this disease. PMID:20673699

Fluorocoxib A enables targeted detection of cyclooxygenase-2 in laser-induced choroidal neovascularization

NASA Astrophysics Data System (ADS)

Uddin, Md. Jashim; Moore, Chauca E.; Crews, Brenda C.; Daniel, Cristina K.; Ghebreselasie, Kebreab; McIntyre, J. Oliver; Marnett, Lawrence J.; Jayagopal, Ashwath

2016-09-01

Ocular angiogenesis is a blinding complication of age-related macular degeneration and other retinal vascular diseases. Clinical imaging approaches to detect inflammation prior to the onset of neovascularization in these diseases may enable early detection and timely therapeutic intervention. We demonstrate the feasibility of a previously developed cyclooxygenase-2 (COX-2) targeted molecular imaging probe, fluorocoxib A, for imaging retinal inflammation in a mouse model of laser-induced choroidal neovascularization. This imaging probe exhibited focal accumulation within laser-induced neovascular lesions, with minimal detection in proximal healthy tissue. The selectivity of the probe for COX-2 was validated in vitro and by in vivo retinal imaging with nontargeted 5-carboxy-X-rhodamine dye, and by blockade of the COX-2 active site with nonfluorescent celecoxib prior to injection of fluorocoxib A. Fluorocoxib A can be utilized for imaging COX-2 expression in vivo for further validation as an imaging biomarker in retinal diseases.

The role of chemoprevention by selective cyclooxygenase-2 inhibitors in colorectal cancer patients - a population-based study

PubMed Central

2012-01-01

Background There are limited population-based studies focusing on the chemopreventive effects of selective cyclooxygenase-2 (COX-2) inhibitors against colorectal cancer. The purpose of this study is to assess the trends and dose–response effects of various medication possession ratios (MPR) of selective COX-2 inhibitor used for chemoprevention of colorectal cancer. Methods A population-based case–control study was conducted using the Taiwan Health Insurance Research Database (NHIRD). The study comprised 21,460 colorectal cancer patients and 79,331 controls. The conditional logistic regression was applied to estimate the odds ratios (ORs) for COX-2 inhibitors used for several durations (5 years, 3 years, 1 year, 6 months and 3 months) prior to the index date. Results In patients receiving selective COX-2 inhibitors, the OR was 0.51 (95% CI=0.29~0.90, p=0.021) for an estimated 5-year period in developing colorectal cancer. ORs showing significant protection effects were found in 10% of MPRs for 5-year, 3-year, and 1-year usage. Risk reduction against colorectal cancer by selective COX-2 inhibitors was observed as early as 6 months after usage. Conclusion Our results indicate that selective COX-2 inhibitors may reduce the development of colorectal cancer by at least 10% based on the MPRs evaluated. Given the limited number of clinical reports from general populations, our results add to the knowledge of chemopreventive effects of selective COX-2 inhibitors against cancer in individuals at no increased risk of colorectal cancer. PMID:23217168

Cox-2 inhibitory effects of naturally occurring and modified fatty acids.

PubMed

Ringbom, T; Huss, U; Stenholm , A; Flock, S; Skattebøl, L; Perera, P; Bohlin, L

2001-06-01

In the search for new cyclooxygenase-2 (COX-2) selective inhibitors, the inhibitory effects of naturally occurring fatty acids and some of their structural derivatives on COX-2-catalyzed prostaglandin biosynthesis were investigated. Among these fatty acids, linoleic acid (LA), alpha-linolenic acid (alpha-LNA), myristic acid, and palmitic acid were isolated from a CH(2)Cl(2) extract of the plant Plantago major by bioassay-guided fractionation. Inhibitory effects of other natural, structurally related fatty acids were also investigated: stearic acid, oleic acid, pentadecanoic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Further, the inhibitory effects of these compounds on COX-2- and COX-1-catalyzed prostaglandin biosynthesis was compared with the inhibition of some synthesized analogues of EPA and DHA with ether or thioether functions. The most potent COX-2-catalyzed prostaglandin biosynthesis inhibitor was all-(Z)-5-thia-8,11,14,17-eicosatetraenoic acid (2), followed by EPA, DHA, alpha-LNA, LA, (7E,11Z,14Z,17Z)-5-thiaeicosa-7,11,14,17-tetraenoic acid, all-(Z)-3-thia-6,9,12,15-octadecatetraenoic acid, and (5E,9Z,12Z,15Z,18Z)-3-oxaheneicosa-5,9,12,15,18-pentaenoic acid, with IC(50) values ranging from 3.9 to180 microM. The modified compound 2 and alpha-LNA were most selective toward COX-2, with COX-2/COX-1 ratios of 0.2 and 0.1, respectively. This study shows that several of the natural fatty acids as well as all of the semisynthetic thioether-containing fatty acids inhibited COX-2-catalyzed prostaglandin biosynthesis, where alpha-LNA and compound 2 showed selectivity toward COX-2.

Overexpression of COX-2 and LMP1 are correlated with lymph node in Tunisian NPC patients.

PubMed

Fendri, Ali; Khabir, Abdelmajid; Hadhri-Guiga, Boutheina; Sellami-Boudawara, Tahia; Ghorbel, Abdelmoonem; Daoud, Jamel; Frikha, Mounir; Jlidi, Rachid; Gargouri, Ali; Mokdad-Gargouri, Raja

2008-07-01

Cyclooxygenase 2 (COX-2) an inducible form of COX is frequently up-regulated in many human tumours. The expression of COX-2 in nasopharyngeal carcinoma (NPC) and its relationship to clinicopathological features were studied in Tunisian patients. COX-2 mRNA was detected in 91% of tumour tissues. Immunohistochemical analysis showed that COX-2 protein was strongly detected in tumour cells and the staining was mainly cytoplasmic. In contrast, COX-2 mRNA and protein were very low or undetectable in normal nasopharyngeal mucosa. Our result showed a significant association of COX-2 overexpression with the lymph node involvement, however, no correlation was observed with age, tumour stage, histological type and distant metastasis. Moreover, we showed that all tumour specimens co-overexpressed COX-2 and the EBV oncoprotein LMP1 corroborating the fact that LPM1 is known to induce COX-2. Altogether, our data suggests that the COX-2 is overexpressed in NPC biopsies and that is linked to the lymph node involvement.

Inhibition of Cyclooxygenase-2 (COX-2) Initiates Autophagy and Potentiates MPTP-Induced Autophagic Cell Death of Human Neuroblastoma Cells, SH-SY5Y: an Inside in the Pathology of Parkinson's Disease.

PubMed

Niranjan, Rituraj; Mishra, Kaushal Prasad; Thakur, Ashwani Kumar

2018-03-01

Cyclooxygenase-2 or COX-2 has been known to be crucial for Parkinson's disease (PD) pathogenesis; however, its exact role is still not known. We first time report that inhibition of COX-2 promotes 1-methyl-4-phenyl 1,2,3,6 tetrahydropyridine (MPTP)-induced neuronal cell death via induction of autophagic mechanisms. We found that treatment with MPTP induced cell death of neuroblastoma cells SH-SY5Y in a dose dependent manner. Treatment of MPTP has also upregulated the expressions of autophagic proteins such as LC3, beclin, ATG-5, and p62. Interestingly, nimesulide, a preferential COX-2 inhibitor, further potentiated the MPTP-induced cell death of human neuroblastoma cells. Treatment of nimesulide with MPTP further potentiated expressions of p62, ATG-5, beclin-1, LC3 autophagic proteins. Furthermore, nimesulide with MPTP increased apoptotic protein cleaved caspase-3 and also induced expression of p53 gene. Interestingly, it was observed that Akt inhibitor significantly increased MPTP-induced cell death of neuroblastoma cells. However, (-) deprenyl, a monoamine oxidase B (MAO B) inhibitor, attenuated MPTP-induced autophagic response and protected cell death. The prior treatment with prostaglandin E2 protected against nimesulide induced-death of neuronal cells. This study confirms that neuroinflammation is associated to the autophagy and may be one of the main pathological mechanisms in Parkinson's disease and other inflammation-associated disorders.

Cyclooxygenase-2 expression after preoperative chemoradiotherapy correlates with more frequent esophageal cancer recurrence

PubMed Central

Yoshikawa, Reigetsu; Fujiwara, Yoshinori; Koishi, Kenji; Kojima, Syoudou; Matsumoto, Tomohiro; Yanagi, Hidenori; Yamamura, Takehira; Hashimoto-Tamaoki, Tomoko; Nishigami, Takashi; Tsujimura, Tohru

2007-01-01

AIM: To investigate the relationship between cycloo-xygenase-2 (COX-2), and vascular endothelial growth factor (VEGF), and to determine the clinical significance of this relationship in esophageal cancer patients undergoing chemoradiotherapy (CRT). METHODS: Immunohistochemical staining was used to evaluate COX-2 and VEGF expression in 40 patients with histologically-confirmed esophageal squamous carcinoma (ESCC) who were undergoing preoperative CRT. RESULTS: Fourteen out of 40 ESCC patients showed a pathological complete response (CR) after CRT. COX-2 and VEGF protein expressions were observed in the cytoplasm of 17 and 13 tumors, respectively, with null expression in 9 and 13 tumors, respectively. COX-2 expression was strongly correlated with VEGF expression (P < 0.05). There were also significant associations between COX-2 expression, tumor recurrence, and lymph-node involvement (P = 0.0277 and P = 0.0095, respectively). COX-2 expression and VEGF expression had significant prognostic value for disease-free survival (log-rank test; P = 0.0073 and P = 0.0341, respectively), but not for overall survival, as assessed by univariate analysis. CONCLUSION: Our results suggest that COX-2 expression correlates with VEGF expression and might be a useful prognostic factor for more frequent tumor recurrence in ESCC patients undergoing neoadjuvant CRT. These findings support the use of anti-angiogenic COX-2 inhibitors in the treatment of ESCC. PMID:17511025

Cyclooxygenase-2 expression in non-metastatic triple-negative breast cancer patients.

PubMed

Mosalpuria, Kailash; Hall, Carolyn; Krishnamurthy, Savitri; Lodhi, Ashutosh; Hallman, D Michael; Baraniuk, Mary S; Bhattacharyya, Anirban; Lucci, Anthony

2014-09-01

Triple-negative breast cancer (TNBC) is characterised by lack of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor (HER)2/neu gene amplification. TNBC patients typically present at a younger age, with a larger average tumor size, higher grade and higher rates of lymph node positivity compared to patients with ER/PR-positive tumors. Cyclooxygenase (COX)-2 regulates the production of prostaglandins and is overexpressed in a variety of solid tumors. In breast cancer, the overexpression of COX-2 is associated with indicators of poor prognosis, such as lymph node metastasis, poor differentiation and large tumor size. Since both TNBC status and COX-2 overexpression are known poor prognostic markers in primary breast cancer, we hypothesized that the COX-2 protein is overexpressed in the primary tumors of TNBC patients. The purpose of this study was to determine whether there exists an association between TNBC status and COX-2 protein overexpression in primary breast cancer. We prospectively evaluated COX-2 expression levels in primary tumor samples obtained from 125 patients with stage I-III breast cancer treated between February, 2005 and October, 2007. Information on clinicopathological factors was obtained from a prospective database. Baseline tumor characteristics and patient demographics were compared between TNBC and non-TNBC patients using the Chi-square and Fisher's exact tests. In total, 60.8% of the patients were classified as having ER-positive tumors, 51.2% were PR-positive, 14.4% had HER-2/neu amplification and 28.0% were classified as TNBC. COX-2 overexpression was found in 33.0% of the patients. TNBC was associated with COX-2 overexpression (P=0.009), PR expression (P=0.048) and high tumor grade (P=0.001). After adjusting for age, menopausal status, body mass index (BMI), lymph node status and neoadjuvant chemotherapy (NACT), TNBC was an independent predictor of COX-2 overexpression (P=0.01). In conclusion, the

Vascular Endothelial Growth Factor Receptor-2 Couples Cyclo-Oxygenase-2 with Pro-Angiogenic Actions of Leptin on Human Endothelial Cells

PubMed Central

Garonna, Elena; Botham, Kathleen M.; Birdsey, Graeme M.; Randi, Anna M.; Gonzalez-Perez, Ruben R.; Wheeler-Jones, Caroline P. D.

2011-01-01

Background The adipocyte-derived hormone leptin influences the behaviour of a wide range of cell types and is now recognised as a pro-angiogenic and pro-inflammatory factor. In the vasculature, these effects are mediated in part through its direct leptin receptor (ObRb)-driven actions on endothelial cells (ECs) but the mechanisms responsible for these activities have not been established. In this study we sought to more fully define the molecular links between inflammatory and angiogenic responses of leptin-stimulated human ECs. Methodology/Principal Findings Immunoblotting studies showed that leptin increased cyclo-oxygenase-2 (COX-2) expression (but not COX-1) in cultured human umbilical vein ECs (HUVEC) through pathways that depend upon activation of both p38 mitogen-activated protein kinase (p38MAPK) and Akt, and stimulated rapid phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2) on Tyr1175. Phosphorylation of VEGFR2, p38MAPK and Akt, and COX-2 induction in cells challenged with leptin were blocked by a specific leptin peptide receptor antagonist. Pharmacological inhibitors of COX-2, the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and p38MAPK abrogated leptin-induced EC proliferation (assessed by quantifying 5-bromo-2′-deoxyuridine incorporation, calcein fluorescence and propidium iodide staining), slowed the increased migration rate of leptin-stimulated cells (in vitro wound healing assay) and inhibited leptin-induced capillary-like tube formation by HUVEC on Matrigel. Inhibition of VEGFR2 tyrosine kinase activity reduced leptin-stimulated p38MAPK and Akt activation, COX-2 induction, and pro-angiogenic EC responses, and blockade of VEGFR2 or COX-2 activities abolished leptin-driven neo-angiogenesis in a chick chorioallantoic membrane vascularisation assay in vivo. Conclusions/Significance We conclude that a functional endothelial p38MAPK/Akt/COX-2 signalling axis is required for leptin's pro-angiogenic actions and that this is

Enhancing radiotherapy with cyclooxygenase-2 enzyme inhibitors: a rational advance?

PubMed

Choy, Hak; Milas, Luka

2003-10-01

Results of preclinical studies suggesting that the efficacy of molecular therapies is enhanced when they are combined with radiation have generated a surge of clinical trials combining these modalities. We reviewed the literature to identify the rationale and experimental foundation supporting the use of cyclooxygenase-2 (COX-2) inhibitors with standard radiotherapy regimens in current clinical trials. Radiation affects the ability of cells to divide and proliferate and induces the expression of genes involved in signaling pathways that promote cell survival or trigger cell death. Future advances in radiotherapy will hinge on understanding mechanisms by which radiation-induced transcription of genes governs cell death and survival, the selective control of this process, and the optimal approaches to combining this knowledge with existing therapeutic modalities. COX-2 is expressed in all stages of cancer, and in several cancers its overexpression is associated with poor prognosis. Evidence from clinical and preclinical studies indicates that COX-2-derived prostaglandins participate in carcinogenesis, inflammation, immune response suppression, apoptosis inhibition, angiogenesis, and tumor cell invasion and metastasis. Clinical trial results have demonstrated that selective inhibition of COX-2 can alter the development and the progression of cancer. In animal models, selective inhibition of COX-2 activity is associated with the enhanced radiation sensitivity of tumors without appreciably increasing the effects of radiation on normal tissue, and preclinical evidence suggests that the principal mechanism of radiation potentiation through selective COX-2 inhibition is the direct increase in cellular radiation sensitivity and the direct inhibition of tumor neovascularization. Results of current early-phase studies of non-small-cell lung, esophageal, cervical, and brain cancers will determine whether therapies that combine COX-2 inhibitors and radiation will enter

Microglia cyclooxygenase-2 activity in experimental gliomas: possible role in cerebral edema formation.

PubMed

Badie, Behnam; Schartner, Jill M; Hagar, Aaron R; Prabakaran, Sakthivel; Peebles, Todd R; Bartley, Becky; Lapsiwala, Samir; Resnick, Daniel K; Vorpahl, Jessica

2003-02-01

Cerebral edema is responsible for significant morbidity and mortality in patients harboring malignant gliomas. To examine the role of inflammatory cells in brain edema formation, we studied the expression cyclooxygenase (COX)-2, a key enzyme in arachidonic acid metabolism, by microglia in the C6 rodent glioma model. The expression of COX-2 in primary microglia cultures obtained from intracranial rat C6 gliomas was examined using reverse transcription-PCR, Western analysis, and prostaglandin E(2) (PGE(2)) enzyme immunoassay. Blood-tumor barrier permeability was studied in the same tumor model using magnetic resonance imaging. In contrast to C6 glioma cells, microglia isolated from intracranial C6 tumors produced high levels of PGE(2) through a COX-2-dependent pathway. To test whether the observed microglia COX-2 activity played a role in brain edema formation in gliomas, tumor-bearing rats were treated with rofecoxib, a selective COX-2 inhibitor. Rofecoxib was as effective as dexamethasone in decreasing the diffusion of contrast material into the brain parenchyma (P = 0.01, rofecoxib versus control animals), suggesting a reduction in blood-tumor barrier permeability. These findings suggest that glioma-infiltrating microglia are a major source of PGE(2) production through the COX-2 pathway and support the use of COX-2 inhibitors as possible alternatives to glucocorticoids in the treatment of peritumoral edema in patients with malignant brain tumors.

Chamomile, a novel and selective COX-2 inhibitor with anti-inflammatory activity.

PubMed

Srivastava, Janmejai K; Pandey, Mitali; Gupta, Sanjay

2009-11-04

Inducible cyclooxygenase (COX-2) has been implicated in the process of inflammation and carcinogenesis. Chamomile has long been used in traditional medicine for the treatment of inflammatory diseases. In this study we aimed to investigate whether chamomile interferes with the COX-2 pathway. We used lipopolysaccharide (LPS)-activated RAW 264.7 macrophages as an in vitro model for our studies. Chamomile treatment inhibited the release of LPS-induced prostaglandin E(2) in RAW 264.7 macrophages. This effect was found to be due to inhibition of COX-2 enzyme activity by chamomile. In addition, chamomile caused reduction in LPS-induced COX-2 mRNA and protein expression, without affecting COX-1 expression. The non-steroidal anti-inflammatory drug, sulindac and a specific COX-2 inhibitor, NS398, were shown to act similarly in LPS-activated RAW 264.7 cells. Our data suggest that chamomile works by a mechanism of action similar to that attributed to non-steroidal anti-inflammatory drugs. These findings add a novel aspect to the biological profile of chamomile which might be important for understanding the usefulness of aqueous chamomile extract in the form of tea in preventing inflammation and cancer.

COX-2 expression induced by diesel particles involves chromatin modification and degradation of HDAC1

EPA Science Inventory

Cyclooxygenase-2 (COX-2) plays an important role in the inflammatory response induced by physiologic and stress stimuli. Exposure to diesel exhaust particulate matter (DEP) has been shown to induce pulmonary inflammation and exacerbate asthma and chronic obstructive pulmonary dis...

Cyclooxygenase-2 and 5-lipoxygenase in dogs with chronic enteropathies.

PubMed

Dumusc, S D; Ontsouka, E C; Schnyder, M; Hartnack, S; Albrecht, C; Bruckmaier, R M; Burgener, I A

2014-01-01

Cyclooxygenase-2 (COX-2) is a key enzyme in the synthesis of pro-inflammatory prostaglandins and 5-lipoxygenase (5-LO) is the major source of leukotrienes. Their role in IBD has been demonstrated in humans and animal models, but not in dogs with chronic enteropathies (CCE). COX-2 and 5-LO are upregulated in dogs with CCE. Fifteen healthy control dogs (HCD), 10 dogs with inflammatory bowel disease (IBD), and 15 dogs with food-responsive diarrhea (FRD). Prospective study. mRNA expression of COX-2, 5-LO, IL-1b, IL-4, IL-6, TNF, IL-10 and TFG-β was evaluated by quantitative real-time RT-PCR in duodenal and colonic biopsies before and after treatment. COX-2 expression in the colon was significantly higher in IBD and FRD before and after treatment (all P < .01). IL-1b was higher in FRD in the duodenum after treatment (P = .021). TGF-β expression was significantly higher in the duodenum of HCD compared to FRD/IBD before treatment (both P < .001) and IBD after treatment (P = .012). There were no significant differences among groups and within groups before and after treatment for IL-4, IL-6, TNF, and IL-10. There was a significant correlation between COX-2 and IL-1b in duodenum and colon before treatment in FRD and IBD, whereas 5-LO correlated better with IL-6 and TNF. IL-10 and TGF-β usually were correlated. COX-2 is upregulated in IBD and FRD, whereas IL-1b and TGF-β seem to be important pro- and anti-inflammatory cytokines, respectively. The use of dual COX/5-LO inhibitors could be an interesting alternative in the treatment of CCE. Copyright © 2014 by the American College of Veterinary Internal Medicine.

Ku80 cooperates with CBP to promote COX-2 expression and tumor growth

PubMed Central

Qin, Yu; Xuan, Yang; Jia, Yunlu; Hu, Wenxian; Yu, Wendan; Dai, Meng; Li, Zhenglin; Yi, Canhui; Zhao, Shilei; Li, Mei; Du, Sha; Cheng, Wei; Xiao, Xiangsheng; Chen, Yiming; Wu, Taihua; Meng, Songshu; Yuan, Yuhui; Liu, Quentin; Huang, Wenlin; Guo, Wei; Wang, Shusen; Deng, Wuguo

2015-01-01

Cyclooxygenase-2 (COX-2) plays an important role in lung cancer development and progression. Using streptavidin-agarose pulldown and proteomics assay, we identified and validated Ku80, a dimer of Ku participating in the repair of broken DNA double strands, as a new binding protein of the COX-2 gene promoter. Overexpression of Ku80 up-regulated COX-2 promoter activation and COX-2 expression in lung cancer cells. Silencing of Ku80 by siRNA down-regulated COX-2 expression and inhibited tumor cell growth in vitro and in a xenograft mouse model. Ku80 knockdown suppressed phosphorylation of ERK, resulting in an inactivation of the MAPK pathway. Moreover, CBP, a transcription co-activator, interacted with and acetylated Ku80 to co-regulate the activation of COX-2 promoter. Overexpression of CBP increased Ku80 acetylation, thereby promoting COX-2 expression and cell growth. Suppression of CBP by a CBP-specific inhibitor or siRNA inhibited COX-2 expression as well as tumor cell growth. Tissue microarray immunohistochemical analysis of lung adenocarcinomas revealed a strong positive correlation between levels of Ku80 and COX-2 and clinicopathologic variables. Overexpression of Ku80 was associated with poor prognosis in patients with lung cancers. We conclude that Ku80 promotes COX-2 expression and tumor growth and is a potential therapeutic target in lung cancer. PMID:25797267

Inhibition of cyclooxygenase-2-dependent survivin mediates decursin-induced apoptosis in human KBM-5 myeloid leukemia cells.

PubMed

Ahn, Quein; Jeong, Soo-Jin; Lee, Hyo-Jung; Kwon, Hee-Young; Han, Ihn; Kim, Hyun Seok; Lee, Hyo-Jeong; Lee, Eun-Ok; Ahn, Kwang Seok; Jung, Min-Hyung; Zhu, Shudong; Chen, Chang-Yan; Kim, Sung-Hoon

2010-12-08

We demonstrate that decursin induces apoptosis via regulation of cyclooxygenase-2 (COX-2) and survivin in leukemic KBM-5 cells. By activating an apoptotic machinery, decursin is cytotoxic to KBM-5 cells. In this apoptotic process, decursin can activate caspase family members and triggers PARP cleavage. At the same time, the expression of COX-2 and survivin in the cells is downregulated. Furthermore, decursin is in synergy with COX-2 inhibitor, celecoxib or NS398 for the induction of apoptosis. Overall, these results suggest that decursin, via inhibiting COX-2 and survivin, sensitizes human leukemia cells to apoptosis and is a potential chemotherapeutic agent to treat this disease. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Cyclooxygenase-2 inhibitory effects and composition of the volatile oil from the dried roots of Lithospermum erythrorhizon.

PubMed

Kawata, Jyunichi; Kameda, Munekazu; Miyazawa, Mitsuo

2008-04-01

The composition of the volatile oil from Lithospermi Radix, the dried roots of Lithospermum erythrorhizon (Boraginaceae), has been investigated by capillary GC and GC-MS. To investigate the anti-inflammatory activity of the oil, in-vitro inhibition of ovine cyclooxygenase-1 and 2 (COX-1 and COX-2) activity by the oil was studied. Fifty-four components of the oil were identified, representing 92.74% of the oil. The main components were 2-methylbutanoic acid (21.50%), 3-methylbutanoic acid (12.61%), 2-methylpropanoic acid (8.99%), methyl linoleate (8.76%), methyl oleate (6.27%), methyl palmitate (6.06%), and 2-methyl-2-butenoic acid (5.74%). Highly selective COX-2 inhibition was observed; at 50 microg/ml the oil inhibited 38.8% of COX-2 activity.

Identification and isolation of the cyclooxygenase-2 inhibitory principle in Isatis tinctoria.

PubMed

Danz, H; Stoyanova, S; Wippich, P; Brattström, A; Hamburger, M

2001-07-01

Various extracts prepared from the traditional dye and medicinal plant Isatis tinctoria L. were submitted to a broad in vitro screening against 16 anti-inflammatory targets. Dichloromethane (DCM) extracts from dried leaves showed a marked cyclooxygenase (COX) inhibitory activity with a preferential effect on COX-2 catalysed prostaglandin synthesis. A supercritical fluid extraction (SFE) procedure employing CO2-modifier mixtures was developed by which the bioactivity profile and chromatographic fingerprint of the DCM extract could be reproduced. High-resolution activity directed on-line identification of the COX-2 inhibitory principle, using a combination of LC-DAD-MS with a microtitre-based bioassay, led to the identification of tryptanthrin (1) as the constituent responsible for essentially all COX-2 inhibitory activity in the crude extract. Following on-line identification, 1 was isolated at preparative scale and its structure confirmed by comparison with synthetic tryptanthrin. In an assay with lipopolysaccharide stimulated Mono Mac 6 cells, tryptanthrin (1) was of comparable potency (IC50 = 64 nM) than the preferential COX-2 inhibitors nimesulide (IC50 = 39 nM) and NS 398 (IC50 = 2 nM). The SFE extract and 1 showed no cytotoxicity in Mono Mac 6 and RAW 264.7 cells when tested at 100 microg/ml and 10 microM, respectively.

Cyclooxygenase-2-dependent bronchoconstriction in perfused rat lungs exposed to endotoxin.

PubMed

Uhlig, S; Nüsing, R; von Bethmann, A; Featherstone, R L; Klein, T; Brasch, F; Müller, K M; Ullrich, V; Wendel, A

1996-05-01

Lipopolysaccharides (LPS), widely used to study the mechanisms of gram-negative sepsis, increase airway resistance by constriction of terminal bronchioles. The role of the cyclooxygenase (COX) isoenzymes and their prostanoid metabolites in this process was studied. Pulmonary resistance, the release of thromboxane (TX) and the expression of COX-2 mRNA were measured in isolated blood-free perfused rat lungs exposed to LPS. LPS induced the release of TX and caused increased airway resistance after about 30 min. Both TX formation and LPS-induced bronchoconstriction were prevented by treatment with the unspecific COX inhibitor acetyl salicylic acid, the specific COX-2 inhibitor CGP-28238, dexamethasone, actinomycin D, or cycloheximide. LPS-induced bronchoconstriction was also inhibited by the TX receptor antagonist BM-13177. The TX-mimetic compound, U-46619, increased airway resistance predominantly by constricting terminal bronchioles. COX-2-specific mRNA in lung tissue was elevated after LPS exposure, and this increase was attenuated by addition of dexamethasone or of actinomycin D. In contrast to LPS, platelet-activating factor (PAF) induced immediate TX release and bronchoconstriction that was prevented by acetyl salicylic acid, but not by CGP-28238. LPS elicits the following biochemical and functional changes in rat lungs: (i) induction of COX-2; (ii) formation of prostaglandins and TX; (iii) activation of the TX receptor on airway smooth muscle cells; (iv) constriction of terminal bronchioles; and (v) increased airway resistance. In contrast to LPS, the PAF-induced TX release is likely to depend on COX-1.

Cyclooxygenase-2 expression and recurrence of colorectal adenomas: effect of aspirin chemoprevention.

PubMed

Benamouzig, Robert; Uzzan, Bernard; Martin, Antoine; Deyra, Jacques; Little, Julian; Girard, Bernard; Chaussade, Stanislas

2010-05-01

Low-dose aspirin reduces the incidence of colorectal cancer and recurrence of adenomas. Cyclooxygenase-2 (COX-2), one of its main target enzymes, is reportedly over-expressed in colorectal adenomas. To assess COX-2 expression, in relation to adenoma recurrence and the protective effect of aspirin, in a large series of colorectal adenomas, recruited from a double-blind randomised controlled trial comparing recurrences after low-dose aspirin or placebo. Follow-up colonoscopies were performed after 1 and 4 years to assess adenoma recurrence. COX-2 expression was assessed by immunohistochemistry for each adenoma obtained at baseline colonoscopy, separately for epithelium, deep stroma and overall. Architecture, grade of dysplasia, K-ras mutation, p53 and cyclin D1 expression were studied. COX-2 expression could be assessed in 219 adenomas from 136 128 adenomas (58%) from 59 patients strongly expressed COX-2. Strong COX-2 expression predominated in adenomas larger than 10 mm (84/129 vs 44/90; p=0.02) and in adenomas showing high-grade dysplasia (22/29 vs 104/188; p=0.04). Deep stromal but not epithelial initial expression of COX-2 predicted adenoma recurrence in the whole population (30/72 patients or 42% strongly expressed deep stromal COX-2 compared with 16/64 or 25% without recurrent adenoma; p=0.04). The protective effect of aspirin was mainly observed in patients in whom COX-2 initial expression was low (RR for recurrence in patients taking aspirin with low COX-2 expression: 0.59; 95% CI 0.39 to 0.90; p=0.02). There was no significant effect of aspirin at the end of the trial. Over-expression of COX-2 was frequent and predominated in large and high-grade dysplasia adenomas. Deep stromal but not epithelial initial expression of COX-2 predicted recurrence of adenomas. Aspirin did not act preferentially on patients whose initial adenomas strongly expressed COX-2.

Bcr-Abl-independent mechanism of resistance to imatinib in K562 cells: Induction of cyclooxygenase-2 (COX-2) by histone deacetylases (HDACs).

PubMed

Kalle, Arunasree M; Sachchidanand, Sachchidanand; Pallu, Reddanna

2010-09-01

Our previous studies have shown that overexpression of MDR1 and cyclooygenase-2 (COX-2) resulted in resistance development to imatinib in chronic myelogenous leukemia (CML) K562 (IR-K562) cells. In the present study, the regulatory mechanism of MDR1 induction by COX-2 was investigated. A gradual overexpression of MDR1 and COX-2 during the process of development was observed. Furthermore, down regulation of MDR1 upon COX-2 knockdown by siRNA showed a decrease in the PKC levels and activation of PKC by addition of PGE(2) to K562 cells, suggesting a role for PKC in the COX-2 mediated induction of MDR1. The present study demonstrates COX-2 induction by HDACs and MDR1 induction by COX-2 via PGE(2)-cAMP-PKC-mediated pathway. Copyright 2010 Elsevier Ltd. All rights reserved.

COX-2 Expression Correlates With Survival in Patients With Osteosarcoma Lung Metastases

PubMed Central

Rodriguez, Nidra I.; Hoots, William Keith; Koshkina, Nadezhda V.; Morales-Arias, Jaime A.; Arndt, Carola A.; Inwards, Carrie Y.; Hawkins, Douglas S.; Munsell, Mark F.; Kleinerman, Eugenie S.

2009-01-01

Summary The purpose of this study was to determine whether a correlation exists between tumor cyclooxygenase (COX)-2 expression and disease-specific survival in patients with osteosarcoma lung metastases. Thirty-six patients diagnosed with osteosarcoma lung metastases between the years 1990 and 2001 were included in this retrospective study. The majority of the patients (72%) presented newly -diagnosed osteosarcoma lung metastases whereas the remaining patients (28%) presented recurrent disease. Clinicopathologic parameters were obtained from patients’ clinical records. Tissue samples were obtained at the time of resection of the lung metastases and stained for COX-2 using immunohistochemistry. Samples were graded according to the intensity of COX-2 staining (grade 0: negative, grade 1: very weak, grade 2: weak, grade 3: moderate, and grade 4: strong). COX-2 staining was correlated with disease-specific survival and clinicopathologic parameters using the Jonckheere-Terpstra and the Kruskal-Wallis tests. All patients with grade 3 or 4 COX-2 expression died of osteosarcoma lung metastases. Ten percent of patients with grade 2 COX-2 expression and 29% of patients with grade 1 expression were alive and free of disease at the last follow-up. By contrast, 60% of the patients with grade 0 COX-2 expression were alive and free of disease at the last follow-up. No association between COX-2 expression and clinicopathologic parameters was found. However, COX-2 expression correlated inversely with disease-specific survival in patients with osteosarcoma lung metastases. Our data indicate that COX-2 expression in metastatic osteosarcoma may have prognostic significance. PMID:18797196

Cell-type-specific roles for COX-2 in UVB-induced skin cancer.

PubMed

Jiao, Jing; Mikulec, Carol; Ishikawa, Tomo-o; Magyar, Clara; Dumlao, Darren S; Dennis, Edward A; Fischer, Susan M; Herschman, Harvey

2014-06-01

In human tumors, and in mouse models, cyclooxygenase-2 (COX-2) levels are frequently correlated with tumor development/burden. In addition to intrinsic tumor cell expression, COX-2 is often present in fibroblasts, myofibroblasts and endothelial cells of the tumor microenvironment, and in infiltrating immune cells. Intrinsic cancer cell COX-2 expression is postulated as only one of many sources for prostanoids required for tumor promotion/progression. Although both COX-2 inhibition and global Cox-2 gene deletion ameliorate ultraviolet B (UVB)-induced SKH-1 mouse skin tumorigenesis, neither manipulation can elucidate the cell type(s) in which COX-2 expression is required for tumorigenesis; both eliminate COX-2 activity in all cells. To address this question, we created Cox-2(flox/flox) mice, in which the Cox-2 gene can be eliminated in a cell-type-specific fashion by targeted Cre recombinase expression. Cox-2 deletion in skin epithelial cells of SKH-1 Cox-2(flox/flox);K14Cre(+) mice resulted, following UVB irradiation, in reduced skin hyperplasia and increased apoptosis. Targeted epithelial cell Cox-2 deletion also resulted in reduced tumor incidence, frequency, size and proliferation rate, altered tumor cell differentiation and reduced tumor vascularization. Moreover, Cox-2(flox/flox);K14Cre(+) papillomas did not progress to squamous cell carcinomas. In contrast, Cox-2 deletion in SKH-1 Cox-2(flox/flox); LysMCre(+) myeloid cells had no effect on UVB tumor induction. We conclude that (i) intrinsic epithelial COX-2 activity plays a major role in UVB-induced skin cancer, (ii) macrophage/myeloid COX-2 plays no role in UVB-induced skin cancer and (iii) either there may be another COX-2-dependent prostanoid source(s) that drives UVB skin tumor induction or there may exist a COX-2-independent pathway(s) to UVB-induced skin cancer. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Cyclooxygenase-2 polymorphisms and the risk of gastric cancer in various degrees of relationship in the Chinese Han population

PubMed Central

LI, YUCHUN; DAI, LIPING; ZHANG, JIANZHONG; WANG, PENG; CHAI, YURONG; YE, HUA; ZHANG, JIANYING; WANG, KAIJUAN

2012-01-01

A number of studies have shown that cyclooxygenase-2 (COX-2) gene polymorphisms were associated with gastric cancer. However, the results from different research groups have not been consistent. The present study aimed to investigate the association between polymorphisms of the cyclooxygenase-2 promoter region (-1195G>A, -765G>C) and gastric cancer patients with various degrees of relationship in the Chinese Han population. COX-2-1195G>A and COX-2-765G>C polymorphisms in 296 gastric cancer patients and 319 control family members were genotyped using polymerase chain reaction-restriction fragment length polymorphism. An increased risk of gastric cancer was observed in subjects with the COX-2-1195AA genotype (OR=2.03; 95% CI, 1.27–3.22), and the association strength decreased as the degree of relationship decreased. Stratification analysis revealed that the OR value of COX-2-1195AA genotype and A carriers exhibited synergy with Helicobacter pylori (H. pylori) infection (AA genotype: OR=2.96; 95% CI, 1.57–5.58; A carriers: OR=2.04; 95% CI, 1.18–3.52). No significant difference was found in each genotype of COX-2-765G>C between gastric cancer patients and control family members, as well as gastric cancer patients with various degrees of relationship. Our study demonstrated that the polymorphism of COX-2-1195AA genotype may be a risk factor for gastric cancer patients with various degrees of relationship among the Chinese Han population. H. pylori infection therefore may enhance the risk of gastric cancer in individuals with the COX-2-1195 AA genotype. PMID:22740864

Cyclooxygenase-2 facilitates dengue virus replication and serves as a potential target for developing antiviral agents.

PubMed

Lin, Chun-Kuang; Tseng, Chin-Kai; Wu, Yu-Hsuan; Liaw, Chih-Chuang; Lin, Chun-Yu; Huang, Chung-Hao; Chen, Yen-Hsu; Lee, Jin-Ching

2017-03-20

Cyclooxygenase-2 (COX-2) is one of the important mediators of inflammation in response to viral infection, and it contributes to viral replication, for example, cytomegalovirus or hepatitis C virus replication. The role of COX-2 in dengue virus (DENV) replication remains unclear. In the present study, we observed an increased level of COX-2 in patients with dengue fever compared with healthy donors. Consistent with the clinical data, an elevated level of COX-2 expression was also observed in DENV-infected ICR suckling mice. Using cell-based experiments, we revealed that DENV-2 infection significantly induced COX-2 expression and prostaglandin E 2 (PGE 2 ) production in human hepatoma Huh-7 cells. The exogenous expression of COX-2 or PGE 2 treatment dose-dependently enhanced DENV-2 replication. In contrast, COX-2 gene silencing and catalytic inhibition sufficiently suppressed DENV-2 replication. In an ICR suckling mouse model, we identified that the COX-2 inhibitor NS398 protected mice from succumbing to life-threatening DENV-2 infection. By using COX-2 promoter-based analysis and specific inhibitors against signaling molecules, we identified that NF-κB and MAPK/JNK are critical factors for DENV-2-induced COX-2 expression and viral replication. Altogether, our results reveal that COX-2 is an important factor for DENV replication and can serve as a potential target for developing therapeutic agents against DENV infection.

Δ9-THC-caused synaptic and memory impairments are mediated through COX-2 signaling

PubMed Central

Yang, Hongwei; Tang, Ya-ping; Sun, Hao; Song, Yunping; Chen, Chu

2013-01-01

SUMMARY Marijuana has been used for thousands of years as a treatment for medical conditions. However, untoward side effects limit its medical value. Here we show that synaptic and cognitive impairments following repeated exposure to Δ9-tetrahydrocannabinol (Δ9-THC) are associated with the induction of cyclooxygenase-2 (COX-2), an inducible enzyme that converts arachidonic acid to prostanoids, in the brain. COX-2 induction by Δ9-THC is mediated via CB1 receptor-coupled G-protein βγ subunits. Pharmacological or genetic inhibition of COX-2 blocks down-regulation and internalization of glutamate receptor subunits and alterations of the dendritic spine density of hippocampal neurons induced by repeated Δ9-THC exposures. Ablation of COX-2 also eliminates Δ9-THC-impaired hippocampal long-term synaptic plasticity, spatial, and fear memories. Importantly, the beneficial effects of decreasing β-amyloid plaques and neurodegeneration by Δ9-THC in Alzheimer’s disease animals are retained in the presence of COX-2 inhibition. These results suggest that the applicability of medical marijuana would be broadened by concurrent inhibition of COX-2. PMID:24267894

Induction of Cyclooxygenase-2 Expression by Hepatitis B Virus Depends on Demethylation-associated Recruitment of Transcription Factors to the Promoter

PubMed Central

2011-01-01

Background The hepatitis B virus (HBV) is a major etiological factor of inflammation and damage to the liver resulting in hepatocellular carcinoma. Transcription factors play important roles in the disordered gene expression and liver injury caused by HBV. However, the molecular mechanisms behind this observation have not been defined. Results In this study, we observed that circulating prostaglandin (PGE) 2 synthesis was increased in patients with chronic hepatitis B infection, and detected elevated cyclooxygenase (COX)-2 expression in HBV- and HBx-expressing liver cells. Likewise, the association of HBx with C/EBPβ contributed to the induction of COX-2. The COX-2 promoter was hypomethylated in HBV-positive cells, and specific demethylation of CpG dinucleotides within each of the two NF-AT sites in the COX-2 promoter resulted in the increased binding affinity of NF-AT to the cognate sites in the promoter, followed by increased COX-2 expression and PGE2 accumulation. The DNA methylatransferase DNMT3B played a key role in the methylation of the COX-2 promoter, and its decreased binding to the promoter was responsible for the regional demethylation of CpG sites, and for the increased binding of transcription factors in HBV-positive cells. Conclusion Our results indicate that upregulation of COX-2 by HBV and HBx is mediated by both demethylation events and recruitment of multiple transcription factors binding to the promoter. PMID:21401943

Apigenin inhibits COX-2, PGE2, and EP1 and also initiates terminal differentiation in the epidermis of tumor bearing mice.

PubMed

Kiraly, Alex J; Soliman, Eman; Jenkins, Audrey; Van Dross, Rukiyah T

2016-01-01

Non-melanoma skin cancer (NMSC) is the most prevalent cancer in the United States. NMSC overexpresses cyclooxygenase-2 (COX-2). COX-2 synthesizes prostaglandins such as PGE2 which promote proliferation and tumorigenesis by engaging G-protein-coupled prostaglandin E receptors (EP). Apigenin is a bioflavonoid that blocks mouse skin tumorigenesis induced by the chemical carcinogens, 7,12-dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA). However, the effect of apigenin on the COX-2 pathway has not been examined in the DMBA/TPA skin tumor model. In the present study, apigenin decreased tumor multiplicity and incidence in DMBA/TPA-treated SKH-1 mice. Analysis of the non-tumor epidermis revealed that apigenin reduced COX-2, PGE2, EP1, and EP2 synthesis and also increased terminal differentiation. In contrast, apigenin did not inhibit the COX-2 pathway or promote terminal differentiation in the tumors. Since fewer tumors developed in apigenin-treated animals which contained reduced epidermal COX-2 levels, our data suggest that apigenin may avert skin tumor development by blocking COX-2. Copyright © 2015 Elsevier Ltd. All rights reserved.

COX-2/EGFR expression and survival among women with adenocarcinoma of the lung

PubMed Central

Van Dyke, Alison L.; Cote, Michele L.; Prysak, Geoffrey M.; Claeys, Gina B.; Wenzlaff, Angie S.; Murphy, Valerie C.; Lonardo, Fulvio; Schwartz, Ann G.

2008-01-01

Previous studies suggest that cyclooxygenase-2 (COX-2) expression may predict survival among patients with non-small cell lung cancer. COX-2 may interact with epidermal growth factor receptor (EGFR), suggesting that combined COX-2/EGFR expression may provide predictive value. The extent to which their independent or combined expression is associated with prognosis in women with adenocarcinoma of the lung is unknown. In the present study, we examined relationships between COX-2 expression (n = 238), EGFR expression (n = 158) and dual COX-2/EGFR expression (n = 157) and survival among women with adenocarcinoma of the lung. Overall survival was estimated by constructing Cox proportional hazards models adjusting for other significant variables and stratifying by stage at diagnosis and race. Clinical or demographic parameters were not associated with either COX-2 or EGFR expression. Patients with COX-2-positive tumors tended to have poorer prognosis than did patients with COX-2-negative tumors [hazard ratio (HR) 1.67, 95% confidence interval (CI) 1.01–2.78]. African-Americans with COX-2-positive tumors had a statistically non-significant higher risk of death than African-Americans with COX-2-negative tumors (HR 5.58, 95% CI 0.64–48.37). No association between COX-2 expression and survival was observed among Caucasians (HR 1.29, 95% CI 0.72–2.30). EGFR expression was associated with a 44% reduction in the risk of death (HR 0.56, 95% CI 0.32–0.98). COX-2−/EGFR+ tumor expression, but not COX-2+/EGFR+ tumor expression, was associated with survival when compared with other combined expression results. In conclusion, COX-2 and EGFR expression, but not combined COX-2+/EGFR+ expression, independently predict survival of women with adenocarcinoma of the lung. PMID:18453539

Chamomile, a novel and selective COX-2 inhibitor with anti-inflammatory activity

PubMed Central

Srivastava, Janmejai K; Pandey, Mitali; Gupta, Sanjay

2009-01-01

Aims Inducible cyclooxygenase (COX-2) has been implicated in the process of inflammation and carcinogenesis. Chamomile has long been used in traditional medicine for the treatment of inflammatory diseases. In this study we aimed to investigate whether chamomile interferes with the COX-2 pathway. Main Methods We used lipopolysaccharide (LPS)-activated RAW 264.7 macrophages as an in vitro model for our studies. Key Findings Chamomile treatment inhibited the release of LPS-induced prostaglandin E(2) in RAW 264.7 macrophages. This effect was found to be due to inhibition of COX-2 enzyme activity by chamomile. In addition, chamomile caused reduction in LPS-induced COX-2 mRNA and protein expression, without affecting COX-1 expression. The non-steroidal anti-inflammatory drug, sulindac and a specific COX-2 inhibitor, NS398, were shown to act similarly in LPS-activated RAW 264.7 cells. Our data suggest that chamomile works by a mechanism of action similar to that attributed to non-steroidal anti-inflammatory drugs. Significance These findings add a novel aspect to the biological profile of chamomile which might be important for understanding the usefulness of aqueous chamomile extract in the form of tea in preventing inflammation and cancer. PMID:19788894

Identification of 2,3-diaryl-pyrazolo[1,5-b]pyridazines as potent and selective cyclooxygenase-2 inhibitors.

PubMed

Beswick, Paul; Bingham, Sharon; Bountra, Chas; Brown, Terry; Browning, Kerry; Campbell, Ian; Chessell, Iain; Clayton, Nick; Collins, Sue; Corfield, John; Guntrip, Stephen; Haslam, Claudine; Lambeth, Paul; Lucas, Fiona; Mathews, Neil; Murkit, Graham; Naylor, Alan; Pegg, Neil; Pickup, Elizabeth; Player, Hazel; Price, Helen; Stevens, Alexander; Stratton, Sharon; Wiseman, Joanne

2004-11-01

GW406381 (8), currently undergoing clinical evaluation for the treatment of inflammatory pain is a member of a novel series of 2,3-diaryl-pyrazolo[1,5-b]pyridazine based cyclooxygenase-2 (COX-2) inhibitors, which have been shown to be highly potent and selective. Several examples of the series, in addition to possessing favourable pharmacokinetic profiles and analgesic activity in vivo, have also demonstrated relatively high brain penetration in the rat compared with the clinically available compounds, which may ultimately prove beneficial in the treatment of pain.

Direct-to-consumer advertising of COX-2 inhibitors: effect on appropriateness of prescribing.

PubMed

Spence, Michele M; Teleki, Stephanie S; Cheetham, T Craig; Schweitzer, Stuart O; Millares, Mirta

2005-10-01

Spending on direct-to-consumer advertising (DTCA) of prescription drugs has increased dramatically in the past several years. An unresolved question is whether such advertising leads to inappropriate prescribing. In this study, the authors use survey and administrative data to determine the association of DTCA with the appropriate prescribing of cyclooxygenase-2 (COX-2) inhibitors for 1,382 patients. Treatment with either a COX-2 or a traditional nonsteroidal anti-inflammatory drug (NSAID) was defined as appropriate or not according to three different definitions of gastrointestinal risk. Patients who saw or heard a COX-2 advertisement and asked their physician about the advertised drug were significantly more likely to be prescribed a COX-2 (versus a NSAID, as recommended by evidence-based guidelines) than all other patients. Findings also suggest that some patients may benefit from DTCA. The authors discuss the need for balanced drug information for consumers, increased physician vigilance in prescribing appropriately, and further study of DTCA.

The role of COX-2 and Nrf2/ARE in anti-inflammation and antioxidative stress: Aging and anti-aging.

PubMed

Luo, Cheng; Urgard, Egon; Vooder, Tõnu; Metspalu, Andres

2011-08-01

Oxidative stress and inflammation are constant features of many chronic diseases and complications, and have been linked to carcinogenesis. Cyclooxygenase 2 (COX-2), a rate-limiting enzyme for the synthesis of prostaglandins, plays important roles in physiology and pathology, but has been a source of controversy within the scientific and clinical community. However, recent work has shown that nuclear factor erythroid-2-related factor-2 (Nrf2) confers protection against oxidative stress. Furthermore, COX-2-dependent electrophile oxo-derivative (EFOX) molecules have been shown to act as anti-inflammatory mediators via activation of the Nrf2-dependent antioxidant response element (ARE). These studies have provided more insight into COX-2-mediated events. The function of all tissues, especially epithelial and endothelial tissues, declines with age, leading to the production of reactive oxygen species (ROS). COX-2 expression increases with aging in most tissues, due in part to ROS, chemical reactions, physical shearing, and dietary molecules. Here we discuss new findings related to COX-2 inflammatory and anti-inflammatory responses. Taken together, we hypothesize that COX-2 levels increase during the aging process because increasing levels of ROSs necessitate the involvement of COX-2-dependent EFOXs for anti-inflammation and Nrf2/ARE signaling for antioxidation. We also propose that COX-2 may act as an intrinsic biological aging clock due to its role in balancing inflammatory and anti-inflammatory responses. Copyright © 2011 Elsevier Ltd. All rights reserved.

The pathophysiological roles of COX-1 and COX-2 in the intestinal smooth muscle contractility under the anaphylactic condition.

PubMed

Kadowaki, Hiroko; Yamamoto, Takeshi; Kageyama-Yahara, Natsuko; Kurokawa, Nobuo; Kadowaki, Makoto

2008-04-01

Various inflammatory mediators released from antigen-activated mast cells are considered to play a key role in the pathogenesis of food allergy. The aim of the present study was to determine the mechanisms underlying the antigen-induced anaphylactic responses in the rat colons. Wistar rats were sensitized by intraperitoneal injection of ovalbumin (OVA). The contractilities of isolated proximal colons of the sensitized rats were studied in the organ bath. OVA challenges of sensitized tissues induced prolonged contractile responses. The antigen-induced contractions were greatly reduced by mast cell stabilizer doxantrazole (10 microM). However, the contractions were resistant to histamine H1 receptor antagonist and prostaglandin D2 receptor antagonist. In contrast, non-selective cyclooxygenase (COX) inhibitor indomethacin (1 microM) significantly reduced the contractions by 61.0%. Furthermore, selective COX-1 inhibitor FR122047 (10 microM) as well as selective COX-2 inhibitor NS-398 (10 microM) significantly inhibited the contractions by 50.1% and 50.3%, respectively. Nevertheless, the transcript levels of COX-2 as well as COX-1 were not upregulated by OVA in the proximal colons of the sensitized rats. The present results indicate that de novo arachidonic acid metabolites synthesis by constitutive COX-1 as well as constitutive COX-2 within mast cells contribute to the altered smooth muscle contractilities in the colons under the anaphylactic condition.

Significance of Cox-2 expression in rectal cancers with or without preoperative radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pachkoria, Ketevan; Zhang Hong; Adell, Gunnar

2005-11-01

Purpose: Radiotherapy has reduced local recurrence of rectal cancers, but the result is not satisfactory. Further biologic factors are needed to identify patients for more effective radiotherapy. Our aims were to investigate the relationship of cyclooxygenase-2 (Cox-2) expression to radiotherapy, and clinicopathologic/biologic variables in rectal cancers with or without radiotherapy. Methods and Materials: Cox-2 expression was immunohistochemically examined in distal normal mucosa (n = 28), in adjacent normal mucosa (n = 107), in primary cancer (n = 138), lymph node metastasis (n = 30), and biopsy (n = 85). The patients participated in a rectal cancer trial of preoperative radiotherapy.more » Results: Cox-2 expression was increased in primary tumor compared with normal mucosa (p < 0.0001), but there was no significant change between primary tumor and metastasis. Cox-2 positivity was or tended to be related to more p53 and Ki-67 expression, and less apoptosis (p {<=} 0.05). In Cox-2-negative cases of either biopsy (p = 0.01) or surgical samples (p = 0.02), radiotherapy was related to less frequency of local recurrence, but this was not the case in Cox-2-positive cases. Conclusion: Cox-2 expression seemed to be an early event involved in rectal cancer development. Radiotherapy might reduce a rate of local recurrence in the patients with Cox-2 weakly stained tumors, but not in those with Cox-2 strongly stained tumors.« less

Lactoferrin from Camelus dromedarius Inhibits Nuclear Transcription Factor-kappa B Activation, Cyclooxygenase-2 Expression and Prostaglandin E2 Production in Stimulated Human Chondrocytes.

PubMed

Rasheed, Naila; Alghasham, Abdullah; Rasheed, Zafar

2016-01-01

Osteoarthritis (OA) is a progressive joint disorder, which remains the leading cause of chronic disability in aged people. Nuclear factor-kappa B (NF)-κB is a major cellular event in OA and its activation by interleukin-1β (IL-1β) plays a critical role in cartilage breakdown in these patients. In this study, we examined the effect of lactoferrin on NF-κB activation, cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) production in stimulated human articular chondrocytes. Human chondrocytes were derived from OA articular cartilage and treated with camel lactoferrin and then stimulated with IL-1β. Gene expression was determined by TaqMan assays and protein expression was studied by Western immunoblotting. NF-κB activity and PGE2 levels were determined by ELISA based assays. NF-κB activity was also determined by treatment of chondrocytes with NF-κB specific inhibitor Bay 11-7082. Lactoferrin inhibited IL-1β-induced activation and nuclear translocation of NF-κB p65 in human OA chondrocytes. Lactoferrin also inhibited mRNA/protein expression of COX-2 and production of PGE2. Moreover, Bay 11-7082 also inhibited IL-1β-induced expression of COX-2 and production of PGE2. The inhibitory effect of lactoferrin on the IL-1β induced expression of COX-2 or production of PGE2 was mediated at least in part via suppression of NF-κB activation. Our data determine camel lactoferrin as a novel inhibitor of IL-1β-induced activation of NF-κB signaling events and production of cartilage-degrading molecule PGE2 via inhibition of COX-2 expressions. These results may have important implications for the development of novel therapeutic strategies for the prevention/treatment of OA and other degenerative/inflammatory diseases. Lactoferrin shows anti-arthritic activity in IL-1β stimulated primary human chondrocytes.Lactoferrin inhibits IL-1β-induced NF-κB activation.Lactoferrin inhibits production of cartilage degrading PGE2 via inhibition of COX-2 expression

MicroRNA-144 is regulated by CP2 and decreases COX-2 expression and PGE2 production in mouse ovarian granulosa cells

PubMed Central

Zhou, Jiawei; Lei, Bin; Li, Huanan; Zhu, Lihua; Wang, Lei; Tao, Hu; Mei, Shuqi; Li, Fenge

2017-01-01

Mammalian folliculogenesis is a complex process in which primordial follicles develop into pre-ovulatory follicles, followed by ovulation to release mature oocytes. In this study, we explored the role of miR-144 in ovulation. miR-144 was one of the differentially expressed microRNAs, which showed 5.59-fold changes, in pre-ovulatory ovarian follicles between Large White and Chinese Taihu sows detected by Solexa deep sequencing. We demonstrated that overexpression of miR-144 significantly decreased the luciferase reporter activity under the control of the cyclooxygenase-2 (COX-2) or mothers against decapentaplegic homologue 4 (Smad4) 3'-untranslated region (3'-UTR) and suppressed COX-2 and Smad4 expression. In contrast, a miR-144 inhibitor increased COX-2 and Smad4 expression in mouse granulosa cells (mGCs). Meanwhile, Smad4 upregulated COX-2 expression, but this effect was abolished when the mGCs were treated with the transforming growth factor beta signalling pathway inhibitor SB431542. Moreover, luciferase reporter, chromatin immunoprecipitation and electrophoretic mobility shift assay results showed that the transcription factor CP2 upregulated miR-144 expression, which partially contributed to the suppression of COX-2 in mGCs. Both CP2 and miR-144 alter prostaglandin E2 (PGE2) production by regulating COX-2 expression. In addition, miR-144 regulated mGC apoptosis and affected follicular atresia, but these activities did not appear to be through COX-2 and Smad4. Taken together, we revealed an important CP2/miR-144/COX-2/PGE2/ovulation pathway in mGCs. PMID:28182010

Exploring selectivity requirements for COX-2 versus COX-1 binding of 2-(5-phenyl-pyrazol-1-yl)-5-methanesulfonylpyridines using topological and physico-chemical parameters.

PubMed

Chakraborty, Santanu; Sengupta, Chandana; Roy, Kunal

2005-04-01

Considering the current need for development of selective cyclooxygenase-2 (COX-2) inhibitors, an attempt has been made to explore physico-chemical requirements of 2-(5-phenyl-pyrazol-1-yl)-5-methanesulfonylpyridines for binding with COX-1 and COX-2 enzyme subtypes and also to explore the selectivity requirements. In this study, E-states of different common atoms of the molecules (calculated according to Kier & Hall), first order valence connectivity and physicochemical parameters (hydrophobicity pi, Hammett sigma and molar refractivity MR of different ring substituents) were used as independent variables along with suitable dummy parameters in the stepwise regression method. The best equation describing COX-1 binding affinity [n = 25, Q2 = 0.606, R(a)2 = 0.702, R2 = 0.752, R = 0.867, s = 0.447, F = 15.2 (df 4, 20)] suggests that the COX-1 binding affinity increases in the presence of a halogen substituent at R1 position and a p-alkoxy or p-methylthio substituent at R2 position. Furthermore, a difluoromethyl group is preferred over a trifluoromethyl group at R position for the COX-1 binding. The best equation describing COX-2 binding affinity [n = 32, Q2 = 0.622, R(a)2= 0.692, R2 = 0.732, R = 0.856, s = 0.265, F = 18.4 (df 4, 27)] shows that the COX-2 binding affinity increases with the presence of a halogen substituent at R1 position and increase of size of R2 substituents. However, it decreases in case of simultaneous presence of 3-chloro and 4-methoxy groups on the phenyl nucleus and in the presence of highly lipophilic R2 substituents. The best selectivity relation [n = 25, Q2 = 0.455, R(a)2 = 0.605, R2 = 0.670, R = 0.819, s = 0.423, F = 10.2 (df 4, 20)] suggests that the COX-2 selectivity decreases in the presence of p-alkoxy group and electron-withdrawing para substituents at R2 position. Again, a trifluoro group is conductive for the selectivity instead of a difluoromethyl group at R position. Furthermore, branching may also play significant role in

Induction of cyclooxygenase-2 expression by allergens in lymphocytes from allergic patients.

PubMed

Chacón, Pedro; Vega, Antonio; Monteseirín, Javier; El Bekay, Rajaa; Alba, Gonzalo; Pérez-Formoso, José Luis; Msartínez, Alberto; Asturias, Juan A; Pérez-Cano, Ramón; Sobrino, Francisco; Conde, José

2005-08-01

Cyclooxygenase (COX) is a key enzyme in prostaglandin (PG) synthesis. Up-regulation of COX-2 expression is responsible for increased PG release during inflammatory conditions and is thought to be also involved in allergic states. In this study, we demonstrate that in human T, B and natural killer lymphocytes from allergic patients, COX-2 expression became induced upon cell challenge with specific allergens and that this process is presumably IgE dependent and occurs after CD23 receptor ligation. This induction took place at both mRNA and protein levels and was accompanied by PGD2 release. IgE-dependent lymphocyte treatment elicited, in parallel, an activation of the MAPK p38 and extracellular signal-regulated kinase 1/2, an enhancement of calcineurin (CaN) activity, and an increase of the DNA-binding activity of the nuclear factor of activated T cells and of NF-kappaB, with a concomitant decrease in the levels of the cytosolic inhibitor of kappaB, IkappaB. In addition, specific chemical inhibitors of MAPK, such as PD098059 and SB203580, as well as MG-132, an inhibitor of proteasomal activity, abolished allergen-induced COX-2 up-regulation, suggesting that this process is mediated by MAPK and NF-kappaB. However, induction of COX-2 expression was not hampered by the CaN inhibitor cyclosporin A. We also examined the effect of a selective COX-2 inhibitor, NS-398, on cytokine production by human lymphocytes. Treatment with NS-398 severely diminished the IgE-dependently induced production of IL-8 and TNF-alpha. These results underscore the relevant role of lymphocyte COX-2 in allergy and suggest that COX-2 inhibitors may contribute to the improvement of allergic inflammation through the reduction of inflammatory mediator production by human lymphocytes.

Design, Synthesis and Biological Evaluation of Novel Peptide-Like Analogues as Selective COX-2 Inhibitors

PubMed Central

Ahmaditaba, Mohammad Ali; Houshdar Tehrani, Mohammad Hassan; Zarghi, Afshin; Shahosseini, Sorayya; Daraei, Bahram

2018-01-01

A new series of peptide-like derivatives containing different aromatic amino acids and possessing pharmacophores of COX-2 inhibitors as SO2Me or N3 attached to the para position of an end phenyl ring was synthesized for evaluation as selective cyclooxygenase-2 (COX-2) inhibitors. The synthetic reactions were based on the solid phase peptide synthesis method using Wang resin. One of the analogues, i.e., compound 2d, as the representative of these series was recognized as the most effective and the highest selective COX-2 inhibitor with IC50 value of 0.08 μM and COX-2 selectivity index of 351.2, among the other synthesized compounds. Molecular docking study was operated to determine possible binding models of compound 2d to COX-2 enzyme. The study showed that the p-azido-phenyl fragment of 2d occupied inside the secondary COX-2 binding site (Arg513, and His90). The structure-activity relationships acquired disclosed that compound 2d with 4-(azido phenyl) group as pharmacophore and histidine as amino acid gives the essential geometry to provide inhibition of the COX-2 enzyme with high selectivity. Compound 2d can be a good candidate for the development of new hits of COX-2 inhibitors.

Effects of specific inhibition of cyclooxygenase-2 on sodium balance, hemodynamics, and vasoactive eicosanoids.

PubMed

Catella-Lawson, F; McAdam, B; Morrison, B W; Kapoor, S; Kujubu, D; Antes, L; Lasseter, K C; Quan, H; Gertz, B J; FitzGerald, G A

1999-05-01

Conventional nonsteroidal anti-inflammatory drugs inhibit both cyclooxygenase (Cox) isoforms (Cox-1 and Cox-2) and may be associated with nephrotoxicity. The present study was undertaken to assess the renal effects of the specific Cox-2 inhibitor, MK-966. Healthy older adults (n = 36) were admitted to a clinical research unit, placed on a fixed sodium intake, and randomized under double-blind conditions to receive the specific Cox-2 inhibitor, MK-966 (50 mg every day), a nonspecific Cox-1/Cox-2 inhibitor, indomethacin (50 mg t.i.d.), or placebo for 2 weeks. All treatments were well tolerated. Both active regimens were associated with a transient but significant decline in urinary sodium excretion during the first 72 h of treatment. Blood pressure and body weight did not change significantly in any group. The glomerular filtration rate (GFR) was decreased by indomethacin but was not changed significantly by MK-966 treatment. Thromboxane biosynthesis by platelets was inhibited by indomethacin only. The urinary excretion of the prostacyclin metabolite 2,3-dinor-6-keto prostaglandin F1alpha was decreased by both MK-966 and indomethacin and was unchanged by placebo. Cox-2 may play a role in the systemic biosynthesis of prostacyclin in healthy humans. Selective inhibition of Cox-2 by MK-966 caused a clinically insignificant and transient retention of sodium, but no depression of GFR. Inhibition of both Cox isoforms by indomethacin caused transient sodium retention and a decline in GFR. Our data suggest that acute sodium retention by nonsteroidal anti-inflammatory drugs in healthy elderly subjects is mediated by the inhibition of Cox-2, whereas depression of GFR is due to inhibition of Cox-1.

RNA interference as a key to knockdown overexpressed cyclooxygenase-2 gene in tumour cells

PubMed Central

Strillacci, A; Griffoni, C; Spisni, E; Manara, M C; Tomasi, V

2006-01-01

Silencing those genes that are overexpressed in cancer and contribute to the survival and progression of tumour cells is the aim of several researches. Cyclooxygenase-2 (COX-2) is one of the most intensively studied genes since it is overexpressed in most tumours, mainly in colon cancer. The use of specific COX-2 inhibitors to treat colon cancer has generated great enthusiasm. Yet, the side effects of some inhibitors emerging during long-term treatment have caused much concern. Genes silencing by RNA interference (RNAi) has led to new directions in the field of experimental oncology. In this study, we detected sequences directed against COX-2 mRNA, that potently downregulate COX-2 gene expression and inhibit phorbol 12-myristate 13-acetate-induced angiogenesis in vitro in a specific, nontoxic manner. Moreover, we found that the insertion of a specific cassette carrying anti-COX-2 short hairpin RNA sequence into a viral vector (pSUPER.retro) greatly increased silencing potency in a colon cancer cell line (HT29) without activating any interferon response. Phenotypically, COX-2 deficient HT29 cells showed a significant impairment of their in vitro malignant behaviour. Thus, the retroviral approach enhancing COX-2 knockdown, mediated by RNAi, proved to be an useful tool to better understand the role of COX-2 in colon cancer. Furthermore, the higher infection efficiency we observed in tumour cells, if compared to normal endothelial cells, may disclose the possibility to specifically treat tumour cells without impairing endothelial COX-2 activity. PMID:16622456

Cyclooxygenase-2-issued prostaglandin e(2) enhances the production of endogenous IL-10, which down-regulates dendritic cell functions.

PubMed

Harizi, Hedi; Juzan, Monique; Pitard, Vincent; Moreau, Jean-François; Gualde, Norbert

2002-03-01

PGE(2) is a well-known immunomodulator produced in the immune response by APCs, such as dendritic cells (DCs), the most potent APC of the immune system. We investigated the PGE(2) biosynthetic capacity of bone marrow-derived DC (BM-DC) and the effects of PG on the APC. We observed that BM-DC produce PGE(2) and other proinflammatory mediators, such as leukotriene B(4) and NO, after LPS exposure. Constitutively present in BM-DC, cyclooxygenase (COX)-1 did not contribute significantly to the total pool of PGE(2) compared with the LPS-induced COX-2-produced PGE(2). Treatment of BM-DC with exogenous PGE(2) induced the production of large amounts of IL-10 and less IL-12p70. In addition, selective inhibition of COX-2, but not COX-1, was followed by significant decrements in PGE(2) and IL-10, a concomitant restoration of IL-12 production, and an enhancement of DC stimulatory potential. In contrast, we found no demonstrable role for leukotriene B(4) or NO. In view of the potential of PGE(2) to stimulate IL-10, we examined the possibility that the suppressive effect of PGE(2) is mediated via IL-10. We found that exogenous IL-10 inhibits IL-12p70 production in the presence of NS-398, a COX-2 selective inhibitor, while the inhibitory effects of PGE(2) were totally reversed by anti-IL-10. We conclude that COX-2-mediated PGE(2) up-regulates IL-10, which down-regulates IL-12 production and the APC function of BM-DC.

In Silico Analysis of the Potential of the Active Compounds Fucoidan and Alginate Derived from Sargassum Sp. as Inhibitors of COX-1 and COX-2.

PubMed

Dewi, Lestari

2016-06-01

The enzyme cyclooxygenase (COX) is an enzyme that catalyzes the formation of one of the mediators of inflammation, the prostaglandins. Inhibition of COX allegedly can improve inflammation-induced pathological conditions. The purpose of the present study was to evaluate the potential of Sargassum sp. components, Fucoidan and alginate, as COX inhibitors. The study was conducted by means of a computational (in silico) method. It was performed in two main stages, the docking between COX-1 and COX-2 with Fucoidan, alginate and aspirin (for comparison) and the analysis of the amount of interactions formed and the residues directly involved in the process of interaction. Our results showed that both Fucoidan and alginate had an excellent potential as inhibitors of COX-1 and COX-2. Fucoidan had a better potential as an inhibitor of COX than alginate. COX inhibition was expected to provide a more favorable effect on inflammation-related pathological conditions. The active compounds Fucoidan and alginate derived from Sargassum sp. were suspected to possess a good potential as inhibitors of COX-1 and COX-2.

Identification of [4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)-2-pyrimidinyl] amines and ethers as potent and selective cyclooxygenase-2 inhibitors.

PubMed

Swarbrick, Martin E; Beswick, Paul J; Gleave, Robert J; Green, Richard H; Bingham, Sharon; Bountra, Chas; Carter, Malcolm C; Chambers, Laura J; Chessell, Iain P; Clayton, Nick M; Collins, Sue D; Corfield, John A; Hartley, C David; Kleanthous, Savvas; Lambeth, Paul F; Lucas, Fiona S; Mathews, Neil; Naylor, Alan; Page, Lee W; Payne, Jeremy J; Pegg, Neil A; Price, Helen S; Skidmore, John; Stevens, Alexander J; Stocker, Richard; Stratton, Sharon C; Stuart, Alastair J; Wiseman, Joanne O

2009-08-01

A novel series of [4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)-2-pyrimidine-based cyclooxygenase-2 (COX-2) inhibitors, which have a different arrangement of substituents compared to the more common 1,2-diarylheterocycle based molecules, have been discovered. For example, 2-(butyloxy)-4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)pyrimidine (47), a member of the 2-pyrimidinyl ether series, has been shown to be a potent and selective inhibitor with a favourable pharmacokinetic profile, high brain penetration and good efficacy in rat models of hypersensitivity.

Δ9-THC-caused synaptic and memory impairments are mediated through COX-2 signaling.

PubMed

Chen, Rongqing; Zhang, Jian; Fan, Ni; Teng, Zhao-Qian; Wu, Yan; Yang, Hongwei; Tang, Ya-Ping; Sun, Hao; Song, Yunping; Chen, Chu

2013-11-21

Marijuana has been used for thousands of years as a treatment for medical conditions. However, untoward side effects limit its medical value. Here, we show that synaptic and cognitive impairments following repeated exposure to Δ(9)-tetrahydrocannabinol (Δ(9)-THC) are associated with the induction of cyclooxygenase-2 (COX-2), an inducible enzyme that converts arachidonic acid to prostanoids in the brain. COX-2 induction by Δ(9)-THC is mediated via CB1 receptor-coupled G protein βγ subunits. Pharmacological or genetic inhibition of COX-2 blocks downregulation and internalization of glutamate receptor subunits and alterations of the dendritic spine density of hippocampal neurons induced by repeated Δ(9)-THC exposures. Ablation of COX-2 also eliminates Δ(9)-THC-impaired hippocampal long-term synaptic plasticity, working, and fear memories. Importantly, the beneficial effects of decreasing β-amyloid plaques and neurodegeneration by Δ(9)-THC in Alzheimer's disease animals are retained in the presence of COX-2 inhibition. These results suggest that the applicability of medical marijuana would be broadened by concurrent inhibition of COX-2. Copyright © 2013 Elsevier Inc. All rights reserved.

The relationship between cyclooxygenase-2 expression and characteristics of malignant transformation in human colorectal adenomas.

PubMed

Sheehan, Katherine M; O'Connell, Fionnuala; O'Grady, Anthony; Conroy, Ronan M; Leader, Mary B; Byrne, Michael F; Murray, Frank E; Kay, Elaine W

2004-06-01

Cyclooxygenase 2 (COX-2) is a target of aspirin and other non-steroidal anti-inflammatory drugs and is implicated in the pathogenesis of colorectal cancer. The objective of this study was to evaluate the extent of COX-2 in pre-malignant colorectal polyps and to assess the relationship between COX-2 and the level of dysplasia in these lesions. Whole polypectomy specimens were retrieved from 123 patients by endoscopic or surgical resection. Following formalin fixation and paraffin embedding, the polyps were evaluated histologically for size, type and grade of dysplasia. The extent of COX-2 expression was measured by the avidin-biotin immunohistochemical technique using a monoclonal COX-2 antibody. The extent of COX-2 expression was graded according to percentage epithelial COX-2 expression. The polyps were of the following histological types: 10 hyperplastic, 35 tubular adenomas, 61 tubulovillous adenomas and 17 villous adenomas. Twenty showed mild dysplasia, 65 moderate dysplasia, and 28 focal or severe dysplasia (including eight with focal invasion). The average polyp size was 1.7 cm. Nine hyperplastic polyps were COX-2-negative and one was COX-2-positive. COX-2 expression was more extensive in larger polyps and in polyps with a higher villous component. There was a significant increase in the extent of COX-2 protein with increasing severity of dysplasia. Within a polyp, there was a focal corresponding increase in COX-2 expression within epithelium showing a higher grade of dysplasia. COX-2 expression is related directly to colorectal adenomatous polyp size, type and grade of dysplasia. This suggests that the role of COX-2 in colorectal cancer may be at an early stage in the adenoma-to-carcinoma sequence and supports the suggestion that inhibition of COX-2 may be useful chemoprevention for this disease.

Red ginseng represses hypoxia-induced cyclooxygenase-2 through sirtuin1 activation.

PubMed

Lim, Wonchung; Shim, Myeong Kuk; Kim, Sikwan; Lee, YoungJoo

2015-06-01

Korean red ginseng (KRG) is a traditional herbal medicine made by steaming and drying the fresh ginseng, leading to chemical transformation of some components by heat. It ameliorates various inflammatory diseases and strengthens the endocrine, immune, and central nervous systems. The cyclooxygenase-2 (COX-2)/prostaglandin E2 pathway in hypoxic cancer cells has important implications for stimulation of inflammation and tumorigenesis. In this study we examined the effects and the mechanism underlying Korean red ginseng water extract (KRG-WE) inhibition of hypoxia-induced COX-2 in human distal lung epithelial A549 cells. The effect of the KRG on suppression of hypoxia-induced COX-2 in A549 cells were determined by Western blot and/or qRT-PCR. The anti-invasive effect of KRG-WE was evaluated on A549 cells using matrigel invasion assay. The activation of glucocorticoid receptor (GR) and sirtuin1 (Sirt1) was examined by using specific inhibitors. We first observed that hypoxia induced COX-2 protein and mRNA levels and promoter activity were suppressed by KRG-WE. Second, we observed that hypoxia-induced cell migration is dramatically reduced by KRG-WE. Third, we found that the effect of KRG-WE was not antagonized by the GR antagonist RU486 implying that the effect is mediated other than GR pathway. Finally, we demonstrated that inhibition of Sirt1 abolished the effect of KRG-WE on hypoxia-induced COX-2 suppression and cell-invasion indicating that the suppression is mediated by Sirt1. Taken together, KRG-WE inhibits the hypoxic induction of COX-2 expression and cell invasion through Sirt1 activation. Our results imply that KRG-WE could be effective for suppression of inflammation under hypoxia. Copyright © 2015 Elsevier GmbH. All rights reserved.

Cyclooxygenase-2 inhibitor enhances the efficacy of a breast cancer vaccine: role of IDO.

PubMed

Basu, Gargi D; Tinder, Teresa L; Bradley, Judy M; Tu, Tony; Hattrup, Christine L; Pockaj, Barbara A; Mukherjee, Pinku

2006-08-15

We report that administration of celecoxib, a specific cyclooxygenase-2 (COX-2) inhibitor, in combination with a dendritic cell-based cancer vaccine significantly augments vaccine efficacy in reducing primary tumor burden, preventing metastasis, and increasing survival. This combination treatment was tested in MMTV-PyV MT mice that develop spontaneous mammary gland tumors with metastasis to the lungs and bone marrow. Improved vaccine potency was associated with an increase in tumor-specific CTLs. Enhanced CTL activity was attributed to a significant decrease in levels of tumor-associated IDO, a negative regulator of T cell activity. We present data suggesting that inhibiting COX-2 activity in vivo regulates IDO expression within the tumor microenvironment; this is further corroborated in the MDA-MB-231 human breast cancer cell line. Thus, a novel mechanism of COX-2-induced immunosuppression via regulation of IDO has emerged that may have implications in designing future cancer vaccines.

Endogenous 2-Arachidonoylglycerol Alleviates Cyclooxygenases-2 Elevation-Mediated Neuronal Injury From SO2 Inhalation via PPARγ Pathway.

PubMed

Li, Ben; Chen, Minjun; Guo, Lin; Yun, Yang; Li, Guangke; Sang, Nan

2015-10-01

Although the health effects of sulfur dioxide (SO2) pollution in the atmospheric environment are not new, epidemiological studies and parallel experimental investigations indicate that acute SO2 exposure causes glutamate-mediated excitotoxicity and even contributes to the outcome of cerebral ischemia. Additionally, the free radical-related inflammatory responses are responsible for neuronal insults and consequent brain disorders. However, few medications are available for preventing the inflammatory responses and relieving the subsequent harmful insults from SO2 inhalation. Here, we show that endocannabinoid 2-arachidonoylglycerol (2-AG) prevents neurotoxicity from SO2 inhalation by suppressing cyclooxygenase-2 (COX-2) overexpression, and this action appears to be mediated via cannabinoid receptor 1 (CB1)-dependent mitogen-activated protein kinase/nuclear factor κB (NF-κB) signaling pathways. Furthermore, CB1-dependent peroxisome proliferator activated receptor γ (PPARγ) expression was an important modulator of the 2-AG-mediated resolution on NF-κB-coupled COX-2 elevation in response to SO2 neuroinflammation. This finding provides evidence of a possible therapeutic effect of endogenous 2-AG regulation for protecting against neurological dysfunction from SO2 inhalation in polluted areas. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Cyclooxygenase-2 expression is related to nuclear grade in ductal carcinoma in situ and is increased in its normal adjacent epithelium

NASA Technical Reports Server (NTRS)

Shim, Veronica; Gauthier, Mona L.; Sudilovsky, Daniel; Mantei, Kristin; Chew, Karen L.; Moore, Dan H.; Cha, Imok; Tlsty, Thea D.; Esserman, Laura J.

2003-01-01

Cyclooxygenase-2 (COX-2) is emerging as an important cancer biomarker and is now an experimental target for solid tumor treatment.However, no study has exclusively focused on COX-2 expression in early lesions such as ductal carcinoma in situ (DCIS). We examined COX-2 expression by immunohistochemistry in 46 cases of women undergoing surgical resection for DCIS. We found that COX-2 expression was detected in 85% of all DCIS specimens, with increased COX-2 staining correlating with higher nuclear grade. Strikingly, COX-2 staining intensity in the normal adjacent epithelium was stronger than in the DCIS lesion itself. Our observations demonstrate that COX-2 is up-regulated in the normal adjacent epithelium and supports the hypothesis that the surrounding epithelial tissue is part of the disease process in DCIS.

Houttuynia cordata, a novel and selective COX-2 inhibitor with anti-inflammatory activity.

PubMed

Li, Weifeng; Zhou, Ping; Zhang, Yanmin; He, Langchong

2011-01-27

Houttuynia cordata Thunb. (Saururaceae; HC) has been long used in traditional oriental medicine for the treatment of inflammation diseases. Modern research has implicated inducible cyclooxygenase-2 (COX-2) as a key regulator of the inflammatory process. In the present study, we aimed to investigate the effect of HC on COX-2. We examined the effects of HC on lipopolysaccharide (LPS)-induced prostaglandin (PG) E(2) production, an indirect indicator of COX-2 activity, and COX-2 gene and protein expression in mouse peritoneal macrophages. LPS-induced mouse peritoneal macrophages were employed as an in vitro model system. LPS-induced PGE(2) production was assessed by enzyme-linked immunosorbant assay and COX-2 protein expression was assessed by Western blot assay. The results showed that HC was able to inhibit the release of LPS-induced PGE(2) from mouse peritoneal macrophages (IC50 value: 44.8 μg/mL). Moreover, the inhibitory activity of HC essential oil elicited a dose-dependent inhibition of COX-2 enzyme activity (IC50 value: 30.9 μg/mL). HC was also found to cause reduction in LPS-induced COX-2 mRNA and protein expression, but did not affect COX-1 expression. The non-steroidal anti-inflammatory drug (NSAID) and specific COX-2 inhibitor NS398 functioned similarly in LPS-induced mouse peritoneal macrophages. Taken together, our data suggest HC mediates inhibition of COX-2 enzyme activity and can affect related gene and protein expression. HC works by a mechanism of action similar to that of NSAIDs. These results add a novel aspect to the biological profile of HC. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Potential interaction of natural dietary bioactive compounds with COX-2.

PubMed

Maldonado-Rojas, Wilson; Olivero-Verbel, Jesus

2011-09-01

Bioactive natural products present in the diet play an important role in several biological processes, and many have been involved in the alleviation and control of inflammation-related diseases. These actions have been linked to both gene expression modulation of pro-inflammatory enzymes, such as cyclooxygenase 2 (COX-2), and to an action involving a direct inhibitory binding on this protein. In this study, several food-related compounds with known gene regulatory action on inflammation have been examined in silico as COX-2 ligands, utilizing AutoDock Vina, GOLD and Surflex-Dock (SYBYL) as docking protocols. Curcumin and all-trans retinoic acid presented the maximum absolute AutoDock Vina-derived binding affinities (9.3 kcal/mol), but genistein, apigenin, cyanidin, kaempferol, and docosahexaenoic acid, were close to this value. AutoDock Vina affinities and GOLD scores for several known COX-2 inhibitors significatively correlated with reported median inhibitory concentrations (R² = 0.462, P < 0.001 and R² = 0.238, P = 0.029, respectively), supporting the computational reliability of the predictions made by our docking simulations. Moreover, docking analysis insinuate the synergistic action of curcumin on celecoxib-induced inhibition of COX-2 may occur allosterically, as this natural compound docks to a place different from the inhibitor binding site. These results suggest that the anti-inflammatory properties of some food-derived molecules could be the result of their direct binding capabilities to COX-2, and this process can be modeled using protein-ligand docking methodologies. Copyright © 2011 Elsevier Inc. All rights reserved.

Cyclooxygenase-2 Selectively Controls Renal Blood Flow Through a Novel PPARβ/δ-Dependent Vasodilator Pathway.

PubMed

Kirkby, Nicholas S; Sampaio, Walkyria; Etelvino, Gisele; Alves, Daniele T; Anders, Katie L; Temponi, Rafael; Shala, Fisnik; Nair, Anitha S; Ahmetaj-Shala, Blerina; Jiao, Jing; Herschman, Harvey R; Xiaomeng, Wang; Wahli, Walter; Santos, Robson A; Mitchell, Jane A

2018-02-01

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in inflammation and cancer targeted by nonsteroidal anti-inflammatory drugs. COX-2 is also expressed constitutively in discreet locations where its inhibition drives gastrointestinal and cardiovascular/renal side effects. Constitutive COX-2 expression in the kidney regulates renal function and blood flow; however, the global relevance of the kidney versus other tissues to COX-2-dependent blood flow regulation is not known. Here, we used a microsphere deposition technique and pharmacological COX-2 inhibition to map the contribution of COX-2 to regional blood flow in mice and compared this to COX-2 expression patterns using luciferase reporter mice. Across all tissues studied, COX-2 inhibition altered blood flow predominantly in the kidney, with some effects also seen in the spleen, adipose, and testes. Of these sites, only the kidney displayed appreciable local COX-2 expression. As the main site where COX-2 regulates blood flow, we next analyzed the pathways involved in kidney vascular responses using a novel technique of video imaging small arteries in living tissue slices. We found that the protective effect of COX-2 on renal vascular function was associated with prostacyclin signaling through PPARβ/δ (peroxisome proliferator-activated receptor-β/δ). These data demonstrate the kidney as the principle site in the body where local COX-2 controls blood flow and identifies a previously unreported PPARβ/δ-mediated renal vasodilator pathway as the mechanism. These findings have direct relevance to the renal and cardiovascular side effects of drugs that inhibit COX-2, as well as the potential of the COX-2/prostacyclin/PPARβ/δ axis as a therapeutic target in renal disease. © 2018 The Authors.

Conservative Secondary Shell Substitution In Cyclooxygenase-2 Reduces Inhibition by Indomethacin Amides and Esters via Altered Enzyme Dynamics

PubMed Central

2015-01-01

The cyclooxygenase enzymes (COX-1 and COX-2) are the therapeutic targets of nonsteroidal anti-inflammatory drugs (NSAIDs). Neutralization of the carboxylic acid moiety of the NSAID indomethacin to an ester or amide functionality confers COX-2 selectivity, but the molecular basis for this selectivity has not been completely revealed through mutagenesis studies and/or X-ray crystallographic attempts. We expressed and assayed a number of divergent secondary shell COX-2 active site mutants and found that a COX-2 to COX-1 change at position 472 (Leu in COX-2, Met in COX-1) reduced the potency of enzyme inhibition by a series of COX-2-selective indomethacin amides and esters. In contrast, the potencies of indomethacin, arylacetic acid, propionic acid, and COX-2-selective diarylheterocycle inhibitors were either unaffected or only mildly affected by this mutation. Molecular dynamics simulations revealed identical equilibrium enzyme structures around residue 472; however, calculations indicated that the L472M mutation impacted local low-frequency dynamical COX constriction site motions by stabilizing the active site entrance and slowing constriction site dynamics. Kinetic analysis of inhibitor binding is consistent with the computational findings. PMID:26704937

Relationship between serum levels of triglycerides and vascular inflammation, measured as COX-2, in arteries from diabetic patients: a translational study

PubMed Central

2013-01-01

Background Inflammation is a common feature in the majority of cardiovascular disease, including Diabetes Mellitus (DM). Levels of pro-inflammatory markers have been found in increasing levels in serum from diabetic patients (DP). Moreover, levels of Cyclooxygenase-2 (COX-2) are increased in coronary arteries from DP. Methods Through a cross-sectional design, patients who underwent CABG were recruited. Vascular smooth muscle cells (VSMC) were cultured and COX-2 was measured by western blot. Biochemical and clinical data were collected from the medical record and by blood testing. COX-2 expression was analyzed in internal mammary artery cross-sections by confocal microscopy. Eventually, PGI2 and PGE2 were assessed from VSMC conditioned media by ELISA. Results Only a high glucose concentration, but a physiological concentration of triglycerides exposure of cultured human VSMC derived from non-diabetic patients increased COX-2 expression .Diabetic patients showed increasing serum levels of glucose, Hb1ac and triglycerides. The bivariate analysis of the variables showed that triglycerides was positively correlated with the expression of COX-2 in internal mammary arteries from patients (r2 = 0.214, P < 0.04). Conclusions We conclude that is not the glucose blood levels but the triglicerydes leves what increases the expression of COX-2 in arteries from DP. PMID:23642086

Platelet cyclooxygenase expression in normal dogs.

PubMed

Thomason, J; Lunsford, K; Mullins, K; Stokes, J; Pinchuk, L; Wills, R; McLaughlin, R; Langston, C; Pruett, S; Mackin, A

2011-01-01

Human platelets express both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2). Variation in COX-2 expression could be a mechanism for variable response to aspirin. The hypotheses were that circulating canine platelets express COX-1 and COX-2, and that aspirin alters COX expression. The objective was to identify changes in platelet COX expression and in platelet function caused by aspirin administration to dogs. Eight female, intact hounds. A single population, repeated measures design was used to evaluate platelet COX-1 and COX-2 expression by flow cytometry before and after aspirin (10 mg/kg Q12h for 10 days). Platelet function was analyzed via PFA-100(®) (collagen/epinephrine), and urine 11-dehydro-thromboxane B(2) (11-dTXB(2)) was measured and normalized to urinary creatinine. Differences in COX expression, PFA-100(®) closure times, and urine 11-dTXB(2 ): creatinine ratio were analyzed before and after aspirin administration. Both COX-1 and COX-2 were expressed in canine platelets. COX-1 mean fluorescent intensity (MFI) increased in all dogs, by 250% (range 63-476%), while COX-2 expression did not change significantly (P = 0.124) after aspirin exposure, with large interindividual variation. PFA-100(®) closure times were prolonged and urine 11-dTXB(2) concentration decreased in all dogs after aspirin administration. Canine platelets express both COX isoforms. After aspirin exposure, COX-1 expression increased despite impairment of platelet function, while COX-2 expression varied markedly among dogs. Variability in platelet COX-2 expression should be explored as a potential mechanism for, or marker of, variable aspirin responsiveness. Copyright © 2011 by the American College of Veterinary Internal Medicine.

Cyclo-oxygenase-2 contributes to constitutive prostanoid production in rat kidney and brain

PubMed Central

2005-01-01

Cyclo-oxygenases (COXs) catalyse the synthesis of PGH2 (prostaglandin H2), which serves as the common substrate for the production of PGE2, PGD2, PGF2α, prostacyclin (or PGI2) and TXs (thromboxanes). While COX-1 is the major isoform responsible for prostanoid synthesis in healthy tissues, little information is available on the contribution of constitutive COX-2 to the various prostanoid synthetic pathways under non-inflammatory conditions. To evaluate further the role of COX-2 in prostanoid biosynthesis, rats were acutely treated with the selective COX-1 inhibitor SC-560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazole] or the selective COX-2 inhibitors MF tricyclic [3-(3,4-difluorophenyl)-4-(4-(methylsulphonyl)phenyl)-2-(5H)-furanone] and DFU [5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl)phenyl-2-(5H)-furanone]. Selected tissues were then processed for a complete analysis of their prostanoid content by liquid chromatography MS. Whereas the treatment with SC-560 caused a 60–70% inhibition in the total prostanoid content of most tissues examined, a significant decrease (35–50%) in total prostanoid content following selective COX-2 inhibition was solely detected for kidney and brain tissues. Analysis of the individual prostanoids reveals significant inhibition of 6-oxo-PGF1α, PGE2, PGD2, PGF2α and TXB2 in the kidney and inhibition of all these prostanoids with the exception of PGD2 in the forebrain. These results demonstrate that constitutively expressed COX-2 contributes to the production of prostanoids in kidney and brain for each of the PGE2, PGI2 and TXB2 pathways under non-inflammatory conditions. Approaches to modulate inflammation through specific inhibition of terminal synthases, such as mPGES-1 (microsomal PGE2 synthase-1), thus have the potential to differ from COX-2 inhibitors and non-selective non-steroidal anti-inflammatory drugs with regard to effects on constitutive prostanoid synthesis and on renal function. PMID

Effect of uric acid on inflammatory COX-2 and ROS pathways in vascular smooth muscle cells.

PubMed

Oğuz, Nurgül; Kırça, Mustafa; Çetin, Arzu; Yeşilkaya, Akın

2017-10-01

Hyperuricemia is thought to play a role in cardiovascular diseases (CVD), including hypertension, coronary artery disease and atherosclerosis. However, exactly how uric acid contributes to these pathologies is unknown. An underlying mechanism of inflammatory diseases, such as atherosclerosis, includes enhanced production of cyclooxygenase-2 (COX-2) and superoxide anion. Here, we aimed to examine the effect of uric acid on inflammatory COX-2 and superoxide anion production and to determine the role of losartan. Primarily cultured vascular smooth muscle cells (VSMCs) were time and dose-dependently induced by uric acid and COX-2 and superoxide anion levels were measured. COX-2 levels were determined by ELISA, and superoxide anion was measured by the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome c method. Uric acid elevated COX-2 levels in a time-dependent manner. Angiotensin-II receptor blocker, losartan, diminished uric-acid-induced COX-2 elevation. Uric acid also increased superoxide anion level in VSMCs. Uric acid plays an important role in CVD pathogenesis by inducing inflammatory COX-2 and ROS pathways. This is the first study demonstrating losartan's ability to reduce uric-acid-induced COX-2 elevation.

Synthesis and biological evaluation of N-difluoromethyl-1,2-dihydropyrid-2-one acetic acid regioisomers: dual inhibitors of cyclooxygenases and 5-lipoxygenase.

PubMed

Yu, Gang; Praveen Rao, P N; Chowdhury, Morshed A; Abdellatif, Khaled R A; Dong, Ying; Das, Dipankar; Velázquez, Carlos A; Suresh, Mavanur R; Knaus, Edward E

2010-04-01

A new group of acetic acid (7a-c, R(1) = H), and propionic acid (7d-f, R(1) = Me), regioisomers wherein a N-difluoromethyl-1,2-dihydropyrid-2-one moiety is attached via its C-3, C-4, and C-5 position was synthesized. This group of compounds exhibited a more potent inhibition, and hence selectivity, for the cyclooxygenase-2 (COX-2) relative to the COX-1 isozyme. Attachment of the N-difluoromethyl-1,2-dihydropyrid-2-one ring system to an acetic acid, or propionic acid, moiety confers potent 5-LOX inhibitory activity, that is, absent in traditional arylacetic acid NSAIDs. 2-(1-Difluoromethyl-2-oxo-1,2-dihydropyridin-5-yl)acetic acid (7c) exhibited the best combination of dual COX-2 and 5-LOX inhibitory activities. Molecular modeling (docking) studies showed that the highly electronegative CHF(2) substituent present in 7c, that showed a modest selectivity for the COX-2 isozyme, is oriented within the secondary pocket (Val523) present in COX-2 similar to the sulfonamide (SO(2)NH(2)) COX-2 pharmacophore present in celecoxib, and that the N-difluoromethyl-1,2-dihydropyrid-2-one pharmacophore is oriented close to the region containing the LOX enzyme catalytic iron (His361, His366, and His545). Accordingly, the N-difluoromethyl-1,2-dihyrdopyrid-2-one moiety possesses properties suitable for the design of dual COX-2/5-LOX inhibitory drugs. 2010 Elsevier Ltd. All rights reserved.

Endoplasmic reticulum stress (ER-stress) by 2-deoxy-D-glucose (2DG) reduces cyclooxygenase-2 (COX-2) expression and N-glycosylation and induces a loss of COX-2 activity via a Src kinase-dependent pathway in rabbit articular chondrocytes.

PubMed

Yu, Seon-Mi; Kim, Song-Ja

2010-11-30

Endoplasmic reticulum (ER) stress regulates a wide range of cellular responses including apoptosis, proliferation, inflammation, and differentiation in mammalian cells. In this study, we observed the role of 2-deoxy-D-glucose (2DG) on inflammation of chondrocytes. 2DG is well known as an inducer of ER stress, via inhibition of glycolysis and glycosylation. Treatment of 2DG in chondrocytes considerably induced ER stress in a dose- and time-dependent manner, which was demonstrated by a reduction of glucose regulated protein of 94 kDa (grp94), an ER stress-inducible protein, as determined by a Western blot analysis. In addition, induction of ER stress by 2DG led to the expression of COX-2 protein with an apparent molecular mass of 66-70kDa as compared with the normally expressed 72-74 kDa protein. The suppression of ER stress with salubrinal (Salub), a selective inhibitor of eif2-alpha dephosphorylation, successfully prevented grp94 induction and efficiently recovered 2DG- modified COX-2 molecular mass and COX-2 activity might be associated with COX-2 N-glycosylation. Also, treatment of 2DG increased phosphorylation of Src in chondrocytes. The inhibition of the Src signaling pathway with PP2 (Src tyrosine kinase inhibitor) suppressed grp94 expression and restored COX-2 expression, N-glycosylation, and PGE2 production, as determined by a Western blot analysis and PGE2 assay. Taken together, our results indicate that the ER stress induced by 2DG results in a decrease of the transcription level, the molecular mass, and the activity of COX-2 in rabbit articular chondrocytes via a Src kinase-dependent pathway.

Correlation between expression of cyclooxygenase-2 and angiogenesis in human gastric adenocarcinoma

PubMed Central

Li, Hong-Xia; Chang, Xin-Ming; Song, Zheng-Jun; He, Shui-Xiang

2003-01-01

AIM: To evaluate the expression of cyclooxygenase (COX-2) and the relationship with tumor angiogenesis and advancement in gastric adenocarcinoma. METHODS: Immunohistochemical stain was used for detecting the expression of COX-2 in 45 resected specimens of gastric adenocarcinoma; the monoclonal antibody against CD34 was used for displaying vascular endothelial cells, and microvascular density (MVD) was detected by counting of CD34-positive vascular endothelial cells. Paracancerous tissues were examined as control. RESULTS: Immunohistological staining with COX-2-specific polyclonal antibody showed cytoplasmic staining in the cancer cells, some atypical hyperplasia and intestinal metaplasia, as well as angiogenic vasculature present within the tumors and prexisting vasculature adjacent to cancer lesions. The rate of expression of COX-2 and MVD index in gastric cancers were significantly increased, compared with those in the paracancerous tissues (77.78 vs 33.33%, 58.13 ± 19.99 vs 24.02 ± 10.28, P < 0.01, P < 0.05, respectively). In 36 gastric carcinoma specimens with lymph node metastasis, the rate of COX-2 expression and MVD were higher than those in the specimens without metostasis (86.11 vs 44.44%, 58.60 ± 18.24 vs 43.54 ± 15.05, P < 0.05, P < 0.05, respectively). The rate of COX-2 expression and MVD in the specimens with invasive serosa were significantly higher than those in the specimens without invasion to serosa (87.88 vs 50.0%, 57.01 ± 18.79 vs 42.35 ± 14.65, P < 0.05, P < 0.05). Moreover, MVD in COX-2-positive specimens was higher than that in COX-2-negative specimens (61.29 ± 14.31 vs 45.38 ± 12.42, P < 0.05). COX-2 expression was positively correlated with MVD (r = 0.63, P < 0.05). CONCLUSION: COX-2 expression might correlate with the occurance and advancement of gastric carcinoma and is involved in tumor angiogenesis in gastric carcinoma. It is likely that COX-2 by inducing angiogenesis can be one of mechanisms which promotes invasion and

Cyclooxygenase-2 Deficiency Leads to Intestinal Barrier Dysfunction and Increased Mortality During Polymicrobial Sepsis 1

PubMed Central

Fredenburgh, Laura E.; Velandia, Margarita M. Suarez; Ma, Jun; Olszak, Torsten; Cernadas, Manuela; Englert, Joshua A.; Chung, Su Wol; Liu, Xiaoli; Begay, Cynthia; Padera, Robert F.; Blumberg, Richard S.; Walsh, Stephen R.; Baron, Rebecca M.; Perrella, Mark A.

2011-01-01

Sepsis remains the leading cause of death in critically ill patients despite modern advances in critical care. Intestinal barrier dysfunction may lead to secondary bacterial translocation and the development of the multiple organ dysfunction syndrome during sepsis. Cyclooxygenase-2 (COX-2) is highly upregulated in the intestine during sepsis and we hypothesized that it may be critical in the maintenance of intestinal epithelial barrier function during peritonitis-induced polymicrobial sepsis. COX-2−/− and COX-2+/+ BALB/c mice underwent cecal ligation and puncture (CLP) or sham surgery. Mice chimeric for COX-2 were derived by bone marrow transplantation and underwent CLP. C2BBe1 cells, an intestinal epithelial cell line, were treated with the COX-2 inhibitor NS-398, PGD2, or vehicle and stimulated with cytokines. COX-2−/− mice developed exaggerated bacteremia and increased mortality compared with COX-2+/+ mice following CLP. Mice chimeric for COX-2 exhibited the recipient phenotype suggesting that epithelial COX-2 expression in the ileum attenuates bacteremia following CLP. Absence of COX-2 significantly increased epithelial permeability of the ileum and reduced expression of the tight junction proteins zonula occludens-1 (ZO-1), occludin, and claudin-1 in the ileum following CLP. Furthermore, PGD2 attenuated cytokine-induced hyperpermeability and ZO-1 downregulation in NS-398-treated C2BBe1 cells. Our findings reveal that absence of COX-2 is associated with enhanced intestinal epithelial permeability and leads to exaggerated bacterial translocation and increased mortality during peritonitis-induced sepsis. Taken together, our results suggest that epithelial expression of COX-2 in the ileum is a critical modulator of tight junction protein expression and intestinal barrier function during sepsis. PMID:21967897

Down-regulation of Cyclooxygenase-2 by the Carboxyl Tail of the Angiotensin II Type 1 Receptor*

PubMed Central

Sood, Rapita; Minzel, Waleed; Rimon, Gilad; Tal, Sharon; Barki-Harrington, Liza

2014-01-01

The enzyme cyclooxygenase-2 (COX-2) plays an important role in the kidney by up-regulating the production of the vasoconstrictor hormone angiotensin II (AngII), which in turn down-regulates COX-2 expression via activation of the angiotensin II type 1 receptor (AT1) receptor. Chemical inhibition of the catalytic activity of COX-2 is a well-established strategy for treating inflammation but little is known of cellular mechanisms that dispose of the protein itself. Here we show that in addition to its indirect negative feedback on COX-2, AT1 also down-regulates the expression of the COX-2 protein via a pathway that does not involve G-protein or β-arrestin-dependent signaling. Instead, AT1 enhances the ubiquitination and subsequent degradation of the enzyme in the proteasome through elements in its cytosolic carboxyl tail (CT). We find that a mutant receptor that lacks the last 35 amino acids of its CT (Δ324) is devoid of its ability to reduce COX-2, and that expression of the CT sequence alone is sufficient to down-regulate COX-2. Collectively these results propose a new role for AT1 in regulating COX-2 expression in a mechanism that deviates from its canonical signaling pathways. Down-regulation of COX-2 by a short peptide that originates from AT1 may present as a basis for novel therapeutic means of eliminating excess COX-2 protein. PMID:25231994

Fluorocoxib A Loaded Nanoparticles Enable Targeted Visualization of Cyclooxygenase-2 in Inflammation and Cancer

PubMed Central

Uddin, Md. Jashim; Werfel, Thomas A.; Crews, Brenda C.; Gupta, Mukesh K.; Kavanaugh, Taylor E.; Kingsley, Philip J.; Boyd, Kelli; Marnett, Lawrence J.; Duvall, Craig L.

2016-01-01

Cyclooxygenase-2 (COX-2) is expressed in virtually all solid tumors and its overexpression is a hallmark of inflammation. Thus, it is a potentially powerful biomarker for the early clinical detection of inflammatory disease and human cancers. We report a reactive oxygen species (ROS) responsive micellar nanoparticle, PPS-b-POEGA, that solubilizes the first fluorescent COX-2-selective inhibitor fluorocoxib A (FA) for COX-2 visualization in vivo. Pharmacokinetics and biodistribution of FA-PPS-b-POEGA nanoparticles (FA-NPs) were assessed after a fully-aqueous intravenous (i.v.) administration in wild-type mice and revealed 4 – 8 h post-injection as an optimal fluorescent imaging window. Carrageenan-induced inflammation in the rat and mouse footpads and 1483 HNSCC tumor xenografts were successfully visualized by FA-NPs with fluorescence up to 10-fold higher than that of normal tissues. The targeted binding of the FA cargo was blocked by pretreatment with the COX-2 inhibitor indomethacin, confirming COX-2-specific binding and local retention of FA at pathological sites. Our collective data indicate that FA-NPs are the first i.v.-ready FA formulation, provide high signal-to-noise in inflamed, premalignant, and malignant tissues, and will uniquely enable clinical translation of the poorly water-soluble FA compound. PMID:27043768

IL-1β Stimulates COX-2 Dependent PGE2 Synthesis and CGRP Release in Rat Trigeminal Ganglia Cells

PubMed Central

Neeb, Lars; Hellen, Peter; Boehnke, Carsten; Hoffmann, Jan; Schuh-Hofer, Sigrid; Dirnagl, Ulrich; Reuter, Uwe

2011-01-01

Objective Pro-inflammatory cytokines like Interleukin-1 beta (IL-1β) have been implicated in the pathophysiology of migraine and inflammatory pain. The trigeminal ganglion and calcitonin gene-related peptide (CGRP) are crucial components in the pathophysiology of primary headaches. 5-HT1B/D receptor agonists, which reduce CGRP release, and cyclooxygenase (COX) inhibitors can abort trigeminally mediated pain. However, the cellular source of COX and the interplay between COX and CGRP within the trigeminal ganglion have not been clearly identified. Methods and Results 1. We used primary cultured rat trigeminal ganglia cells to assess whether IL-1β can induce the expression of COX-2 and which cells express COX-2. Stimulation with IL-1β caused a dose and time dependent induction of COX-2 but not COX-1 mRNA. Immunohistochemistry revealed expression of COX-2 protein in neuronal and glial cells. 2. Functional significance was demonstrated by prostaglandin E2 (PGE2) release 4 hours after stimulation with IL-1β, which could be aborted by a selective COX-2 (parecoxib) and a non-selective COX-inhibitor (indomethacin). 3. Induction of CGRP release, indicating functional neuronal activation, was seen 1 hour after PGE2 and 24 hours after IL-1β stimulation. Immunohistochemistry showed trigeminal neurons as the source of CGRP. IL-1β induced CGRP release was blocked by parecoxib and indomethacin, but the 5-HT1B/D receptor agonist sumatriptan had no effect. Conclusion We identified a COX-2 dependent pathway of cytokine induced CGRP release in trigeminal ganglia neurons that is not affected by 5-HT1B/D receptor activation. Activation of neuronal and glial cells in the trigeminal ganglion by IL-β leads to an elevated expression of COX-2 in these cells. Newly synthesized PGE2 (by COX-2) in turn activates trigeminal neurons to release CGRP. These findings support a glia-neuron interaction in the trigeminal ganglion and demonstrate a sequential link between COX-2 and CGRP. The

Upregulation of Cyclooxygenase-2 Expression in Porcine Macula Densa With Chronic Nitric Oxide Synthase Inhibition

PubMed Central

Kommareddy, M.; McAllister, R. M.; Ganjam, V. K.; Turk, J. R.; Laughlin, M. Harold

2012-01-01

The objective of this study was to investigate the effects of chronic inhibition of nitric oxide synthase (NOS) on cyclooxygenase-2 (COX-2) expression in the macula densa (MD) of swine, as well as the effects on expression of related proteins. Adult female Yucatan swine were given either tap water (control, n = 6) or water with NG-nitro-l-arginine methyl ester (L-NAME, 100 mg/liter, n = 5) for a minimum of 30 days. Duplicate samples of kidney were fixed or snap frozen. There was a significant (P = .0082) upregulation of COX-2 mRNA expression in the MD of L-NAME, as well as an apparent increase in COX-2 protein. Plasma renin activity also increased with L-NAME treatment (control, 0.34 ± 0.08 ng/ml; L-NAME, 1.26 ± 0.03 ng/ml; P = .00000003). There were no differences between groups in expression of either inducible NOS or renin protein or in serum electrolyte concentrations. In conclusion, with chronic inhibition of NOS, COX-2 in MD is upregulated, perhaps to compensate for loss of nitric oxide. Increases in COX-2 products may counteract renal arteriolar constriction and sustain renin release. PMID:21160023

Upregulation of cyclooxygenase-2 expression in porcine macula densa with chronic nitric oxide synthase inhibition.

PubMed

Kommareddy, M; McAllister, R M; Ganjam, V K; Turk, J R; Laughlin, M Harold

2011-11-01

The objective of this study was to investigate the effects of chronic inhibition of nitric oxide synthase (NOS) on cyclooxygenase-2 (COX-2) expression in the macula densa (MD) of swine, as well as the effects on expression of related proteins. Adult female Yucatan swine were given either tap water (control, n = 6) or water with N (G)-nitro-L-arginine methyl ester (L-NAME, 100 mg/liter, n = 5) for a minimum of 30 days. Duplicate samples of kidney were fixed or snap frozen. There was a significant (P = .0082) upregulation of COX-2 mRNA expression in the MD of L-NAME, as well as an apparent increase in COX-2 protein. Plasma renin activity also increased with L-NAME treatment (control, 0.34 ± 0.08 ng/ml; L-NAME, 1.26 ± 0.03 ng/ml; P = .00000003). There were no differences between groups in expression of either inducible NOS or renin protein or in serum electrolyte concentrations. In conclusion, with chronic inhibition of NOS, COX-2 in MD is upregulated, perhaps to compensate for loss of nitric oxide. Increases in COX-2 products may counteract renal arteriolar constriction and sustain renin release.

Structure-based design, synthesis, molecular docking study and biological evaluation of 1,2,4-triazine derivatives acting as COX/15-LOX inhibitors with anti-oxidant activities.

PubMed

Khoshneviszadeh, Mehdi; Shahraki, Omolbanin; Khoshneviszadeh, Mahsima; Foroumadi, Alireza; Firuzi, Omidreza; Edraki, Najmeh; Nadri, Hamid; Moradi, Alireza; Shafiee, Abbas; Miri, Ramin

2016-12-01

A set of 1,2,4-triazine derivatives were designed as cyclooxygenase-2 (COX-2) inhibitors. These compounds were synthesized and screened for inhibition of cyclooxygenases (COX-1 and COX-2) based on a cellular assay using human whole blood (HWB) and lipoxygenase (LOX-15) that are key enzymes in inflammation. The results showed that 3-(2-(benzo[d][1,3]dioxol-5-ylmethylene)hydrazinyl)-5,6-bis(4-methoxyphenyl)-1,2,4-triazine (G11) was identified as the most potent COX-2 inhibitor (78%) relative to COX-1 (50%). Ferric reducing anti-oxidant power (FRAP) assay revealed that compound G10 possesses the highest anti-oxidant activity. The compound G3 with IC50 value of 124 μM was the most potent compound in LOX inhibitory assay. Molecular docking was performed and a good agreement was observed between computational and experimental results.

Cyclooxygenase-2/carbonic anhydrase-IX up-regulation promotes invasive potential and hypoxia survival in colorectal cancer cells

PubMed Central

Sansone, Pasquale; Piazzi, Giulia; Paterini, Paola; Strillacci, Antonio; Ceccarelli, Claudio; Minni, Francesco; Biasco, Guido; Chieco, Pasquale; Bonafè, Massimiliano

2009-01-01

Inflammation promotes colorectal carcinogenesis. Tumour growth often generates a hypoxic environment in the inner tumour mass. We here report that, in colon cancer cells, the expression of the pro-inflammatory enzyme cyclooxygenase-2 (COX-2) associates with that of the hypoxia response gene carbonic anhydrase-IX (CA-IX). The COX-2 knockdown, achieved by the stable infection of a COX-2 specific short harpin RNA interference (shCOX-2), down-regulates CA-IX gene expression. In colorectal cancer (CRC) cells, PGE2, the main COX-2 gene products, promotes CA-IX gene expression by ERK1/2 activation. In normoxic environment, shCOX-2 infected/CA-IX siRNA transfected CRC cells show a reduced level of active metalloproteinase-2 (MMP-2) that associates with a decreased extracellular matrix invasion capacity. In presence of hypoxia, COX-2 gene expression and PGE2 production increase. The knockdown of COX-2/CA-IX blunts the survival capability of CRC cells in hypoxia. At a high cell density, a culture condition that creates a mild pericellular hypoxic environment, the expression of COX-2/CA-IX genes is increased and triggers the invasive potential of colon cancer cells. In human colon cancer tissues, COX-2/CA-IX protein expression levels, assessed by Western blot and immunohistochemistry, correlate each other and increase with tumour stage. In conclusion, these data indicate that COX-2/CA-IX interplay promotes the aggressive behaviour of CRC cells. PMID:19017360

ERK1/2/COX-2/PGE2 signaling pathway mediates GPR91-dependent VEGF release in streptozotocin-induced diabetes

PubMed Central

Li, Tingting; Hu, Jianyan; Du, Shanshan; Chen, Yongdong; Wang, Shuai

2014-01-01

Purpose Retinal vascular dysfunction caused by vascular endothelial growth factor (VEGF) is the major pathological change that occurs in diabetic retinopathy (DR). It has recently been demonstrated that G protein-coupled receptor 91 (GPR91) plays a major role in both vasculature development and retinal angiogenesis. In this study, we examined the signaling pathways involved in GPR91-dependent VEGF release during the early stages of retinal vascular change in streptozotocin-induced diabetes. Methods Diabetic rats were assigned randomly to receive intravitreal injections of shRNA lentiviral particles targeting GPR91 (LV.shGPR91) or control particles (LV.shScrambled). Accumulation of succinate was assessed by gas chromatography-mass spectrometry (GC-MS). At 14 weeks, the ultrastructure and function of the retinal vessels of diabetic retinas with or without shRNA treatment were assessed using hematoxylin and eosin (HE) staining, transmission electron microscopy (TEM), and Evans blue dye permeability. The expression of GPR91, extracellular signal-regulated kinases 1 and 2 (ERK1/2) and cyclooxygenase-2 (COX-2) were measured using immunofluorescence and western blotting. COX-2 and VEGF mRNA were determined by quantitative RT–PCR. Prostaglandin E2 (PGE2) and VEGF secretion were detected using an enzyme-linked immunosorbent assay. Results Succinate exhibited abundant accumulation in diabetic rat retinas. The retinal telangiectatic vessels, basement membrane thickness, and Evans blue dye permeability were attenuated by treatment with GPR91 shRNA. In diabetic rats, knockdown of GPR91 inhibited the activities of ERK1/2 and COX-2 as well as the expression of PGE2 and VEGF. Meanwhile, COX-2, PGE2, and VEGF expression was inhibited by ERK1/2 inhibitor U0126 and COX-2 inhibitor NS-398. Conclusions Our data suggest that hyperglycemia causes succinate accumulation and GPR91 activity in retinal ganglion cells, which mediate VEGF-induced retinal vascular change via the ERK1/2/COX-2

COX-2 expression and function in the hyperalgesic response to paw inflammation in mice

PubMed Central

Jain, Naveen K.; Ishikawa, Tomo-o; Spigelman, Igor; Herschman, Harvey R.

2009-01-01

Peripheral inflammation and edema are often accompanied by primary and secondary hyperalgesia which are mediated by both peripheral and central mechanisms. The role of cyclooxygenase-2 (COX-2)-mediated prostanoid production in hyperalgesia is a topic of substantial current interest. We have established a murine foot-pad inflammation model in which both pharmacologic and genetic tools can be used to characterize the role of COX-2 in hyperalgesia. Zymosan, an extract from yeast, injected into the plantar surface of the hind paw induces an edema response and an increase in COX-2 expression in the hindpaw, spinal cord and brain. Zymosan-induced primary hyperalgesia, measured as a decrease in hindpaw withdrawal latency in response to a thermal stimulus, is long-lasting and is not inhibited by pre-treatment with the systemic COX-2 selective inhibitor, parecoxib (20 mg/kg). In contrast, the central component of hyperalgesia, measured as a reduction in tail flick latency in response to heat, is reduced by parecoxib. Zymosan-induced primary hyperalgesia in Cox-2−/− mice is similar to that of their Cox-2+/+ littermate controls. However, the central component of hyperalgesia is substantially reduced in Cox-2−/− versus Cox-2+/+ mice, and returns to baseline values much more rapidly. Thus pharmacological data suggest, and genetic experiments confirm, (i) that primary hyperalgesia in response to zymosan inflammation in the mouse paw is not mediated by COX-2 function and (ii) that COX-2 function plays a major role in the central component of hyperalgesia in this model of inflammation. PMID:18829279

Regression of experimentally induced endometriosis with a new selective cyclooxygenase-2 enzyme inhibitor.

PubMed

Kilico, Ismail; Kokcu, Arif; Kefeli, Mehmet; Kandemir, Bedri

2014-01-01

Cyclooxygenase-2 (COX-2) levels increase in women with endometriosis. COX-2, via increasing prostaglandin E2, contributes to an increase in vascular endothelial growth factor. In this way, COX-2 may contribute to the progression and continuity of endometriosis. We investigated the effect of dexketoprofen trometamol, a new selective COX-2 enzyme inhibitor, on experimentally induced endometriotic cysts. Experimental endometriotic cysts were created in 60 adult female Wistar albino rats. The rats were randomized to 2 equal groups, a control (group Con) and a dexketoprofen (group Dex) group. Six weeks later, cyst volumes were measured as in vivo (volume 1). Following volume 1 measurement, for 4 weeks group Con received 0.1 ml distilled water; group Dex received 0.375 mg dexketoprofen trometamol/0.1 ml distilled water, intramuscularly, twice a day. At the end of administration, the cyst volumes were remeasured (volume 2), and the cysts totally excised and weighed. Glandular (GT) and stromal tissues (ST) and natural killer (NK) cell contents in the cyst wall were scored. NK cell content and volume 1 were not different between the 2 groups. Volume 2, cyst weight, and GT and ST contents in group Dex were significantly lower than those in group Con. Dexketoprofen trometamol significantly reduced the development of experimentally induced endometriotic cysts both macroscopically and microscopically.

Angiotensin-(1-7)-Induced Plasticity Changes in the Lateral Amygdala Are Mediated by COX-2 and NO

ERIC Educational Resources Information Center

Albrecht, Doris

2007-01-01

It is known from studies outside the brain that upon binding to its receptor, angiotensin-(1-7) elicits the release of prostanoids and nitric oxide (NO). Cyclooxygenase (COX) is a key enzyme that converts arachidonic acid to prostaglandins. Since there are no data available so far on the role of COX-2 in the amygdala, in a first step we…

In Silico Analysis of the Potential of the Active Compounds Fucoidan and Alginate Derived from Sargassum Sp. as Inhibitors of COX-1 and COX-2

PubMed Central

Dewi, Lestari

2016-01-01

Introduction: The enzyme cyclooxygenase (COX) is an enzyme that catalyzes the formation of one of the mediators of inflammation, the prostaglandins. Inhibition of COX allegedly can improve inflammation-induced pathological conditions. Aim: The purpose of the present study was to evaluate the potential of Sargassum sp. components, Fucoidan and alginate, as COX inhibitors. Material and methods: The study was conducted by means of a computational (in silico) method. It was performed in two main stages, the docking between COX-1 and COX-2 with Fucoidan, alginate and aspirin (for comparison) and the analysis of the amount of interactions formed and the residues directly involved in the process of interaction. Results: Our results showed that both Fucoidan and alginate had an excellent potential as inhibitors of COX-1 and COX-2. Fucoidan had a better potential as an inhibitor of COX than alginate. COX inhibition was expected to provide a more favorable effect on inflammation-related pathological conditions. Conclusion: The active compounds Fucoidan and alginate derived from Sargassum sp. were suspected to possess a good potential as inhibitors of COX-1 and COX-2. PMID:27594740

Radiation-induced cyclooxygenase 2 up-regulation is dependent on redox status in prostate cancer cells.

PubMed

Li, Lingyun; Steinauer, Kirsten K; Dirks, Amie J; Husbeck, Bryan; Gibbs, Iris; Knox, Susan J

2003-12-01

Cyclooxygenase 2 (COX2) is the inducible isozyme of COX, a key enzyme in arachidonate metabolism and the conversion of arachidonic acid (AA) to prostaglandins (PGs) and other eicosanoids. Previous studies have demonstrated that the COX2 protein is up-regulated in prostate cancer cells after irradiation and that this results in elevated levels of PGE(2). In the present study, we further investigated whether radiation-induced COX2 up-regulation is dependent on the redox status of cells from the prostate cancer cell line PC-3. l-Buthionine sulfoximine (BSO), which inhibits gamma glutamyl cysteine synthetase (gammaGCS), and the antioxidants alpha-lipoic acid and N-acetyl-l-cysteine (NAC) were used to modulate the cellular redox status. BSO decreased the cellular GSH level and increased cellular reactive oxygen species (ROS) in PC-3 cells, whereas alpha-lipoic acid and NAC increased the GSH level and decreased cellular ROS. Both radiation and the oxidant H(2)O(2) had similar effects on COX2 up-regulation and PGE(2) production in PC-3 cells, suggesting that radiation-induced COX2 up-regulation is secondary to the production of ROS. The relative increases in COX2 expression and PGE(2) production induced by radiation and H(2)O(2) were even greater when PC-3 cells were pretreated with BSO. When the cells were pretreated with alpha-lipoic acid or NAC for 24 h, both radiation- and H(2)O(2)-induced COX2 up-regulation and PGE(2) production were markedly inhibited. These results demonstrate that radiation-induced COX2 up-regulation in prostate cancer cells is modulated by the cellular redox status. Radiation-induced increases in ROS levels contribute to the adaptive response of PC-3 cells, resulting in elevated levels of COX2.

Nonylphenol regulates cyclooxygenase-2 expression via Ros-activated NF-κB pathway in sertoli TM4 cells.

PubMed

Liu, Xiaozhen; Nie, Shaoping; Huang, Danfei; Xie, Mingyong

2015-09-01

The aim of this study was to investigate the signaling pathways involved in the cyclooxygenase (COX)-2 regulation induced by nonylphenol (NP) in mouse testis Sertoli TM4 cells. Our results showed that treatment of TM4 cells with NP increased COX-2 protein expression and interleukin-6 (IL)-6 and prostaglandin E2 (PGE2) secretion in a dose-dependent manner. Pretreatment with reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC), attenuated NP-induced ROS production, COX-2 expression, and IL-6 and PGE2 release in TM4 cells. Exposure to NP stimulated activation of NF-κB, whereas the NF-κB inhibitor, pyrrolidine dithiocarbamate, attenuated NP-enhanced COX-2 expression and IL-6 and PGE2 release in TM4 cells in a dose-dependent manner. Furthermore, NAC blocked NP-induced activation of NF-κB. In addition, inhibition of COX-2 mitigated NP-induced IL-6 release. In conclusion, NP induced ROS generation, activation of NF-κB pathway, COX-2 upregulation, and IL-6 and PGE2 secretion in TM4 cells. NP may regulate COX-2 expression via ROS-activated NF-κB pathway in Sertoli TM4 cells. © 2014 Wiley Periodicals, Inc.

Human umbilical vein: involvement of cyclooxygenase-2 pathway in bradykinin B1 receptor-sensitized responses.

PubMed

Errasti, A E; Rey-Ares, V; Daray, F M; Rogines-Velo, M P; Sardi, S P; Paz, C; Podestá, E J; Rothlin, R P

2001-08-01

In isolated human umbilical vein (HUV), the contractile response to des-Arg9-bradykinin (des-Arg9-BK), selective BK B1 receptor agonist, increases as a function of the incubation time. Here, we evaluated whether cyclooxygenase (COX) pathway is involved in BK B1-sensitized response obtained in 5-h incubated HUV rings. The effect of different concentrations of indomethacin, sodium salicylate, ibuprofen, meloxicam, lysine clonixinate or NS-398 administrated 30 min before concentration-response curves (CRC) was studied. All treatments produced a significant rightward shift of the CRC to des-Arg9-BK in a concentration-dependent manner, which provides pharmacological evidence that COX pathway is involved in the BK B1 responses. Moreover, in this tissue, the NS-398 pKb (5.2) observed suggests that COX-2 pathway is the most relevant. The strong correlation between published pIC50 for COX-2 and the NSAIDs' pKbs estimated further supports the hypothesis that COX-2 metabolites are involved in BK B1 receptor-mediated responses. In other rings, indomethacin (30, 100 micromol/l) or NS-398 (10, 30 micromol/l) produced a significant rightward shift of the CRC to BK, selective BK B2 agonist, and its pKbs were similar to the values to inhibit BK B1 receptor responses, suggesting that COX-2 pathway also is involved in BK B2 receptor responses. Western blot analysis shows that COX-1 and COX-2 isoenzymes are present before and after 5-h in vitro incubation and apparently COX-2 does not suffer additional induction.

Reduced COX-2 expression in aged mice is associated with impaired fracture healing.

PubMed

Naik, Amish A; Xie, Chao; Zuscik, Michael J; Kingsley, Paul; Schwarz, Edward M; Awad, Hani; Guldberg, Robert; Drissi, Hicham; Puzas, J Edward; Boyce, Brendan; Zhang, Xinping; O'Keefe, Regis J

2009-02-01

The cellular and molecular events responsible for reduced fracture healing with aging are unknown. Cyclooxygenase 2 (COX-2), the inducible regulator of prostaglandin E(2) (PGE(2)) synthesis, is critical for normal bone repair. A femoral fracture repair model was used in mice at either 7-9 or 52-56 wk of age, and healing was evaluated by imaging, histology, and gene expression studies. Aging was associated with a decreased rate of chondrogenesis, decreased bone formation, reduced callus vascularization, delayed remodeling, and altered expression of genes involved in repair and remodeling. COX-2 expression in young mice peaked at 5 days, coinciding with the transition of mesenchymal progenitors to cartilage and the onset of expression of early cartilage markers. In situ hybridization and immunohistochemistry showed that COX-2 is expressed primarily in early cartilage precursors that co-express col-2. COX-2 expression was reduced by 75% and 65% in fractures from aged mice compared with young mice on days 5 and 7, respectively. Local administration of an EP4 agonist to the fracture repair site in aged mice enhanced the rate of chondrogenesis and bone formation to levels observed in young mice, suggesting that the expression of COX-2 during the early inflammatory phase of repair regulates critical subsequent events including chondrogenesis, bone formation, and remodeling. The findings suggest that COX-2/EP4 agonists may compensate for deficient molecular signals that result in the reduced fracture healing associated with aging.

Injured nerve-derived COX2/PGE2 contributes to the maintenance of neuropathic pain in aged rats.

PubMed

Ma, Weiya; Chabot, Jean-Guy; Vercauteren, Freya; Quirion, Remi

2010-07-01

Neuropathic pain (NeP) is a debilitating disease afflicting mostly the aged population. Inflammatory responses in injured nerves play a pivotal role in the pathogenesis of NeP. Injured nerve derived cyclooxygenase 2/prostaglandin E2 (COX2/PGE2) contributes to the genesis of NeP at the early stage in young rats. Here we show that COX2/PGE2 is involved in the maintenance of NeP at a chronic stage in aged rats. Eighteen months after partial sciatic nerve ligation (PSNL), NeP remained prominent in aged rats. COX2 expressing macrophages and PGE2 levels were increased in injured nerves. PGE2 receptors (EP1 and EP4) and pain-related ion channel transient receptor potential vanilloid-1 (TRPV1) were increased in the ipsilateral dorsal root ganglion (DRG) neurons of aged PSNL rats. Perineural injection of a selective COX2 inhibitor NS-398 relieved NeP, reversed PSNL increased expression of EP1, EP4 and TRPV1 and suppressed the levels of pain-related peptide substance P and calcitonin gene-related peptide in DRG neurons. These data suggest that injured nerve-derived PGE2 contributes to the maintenance of NeP at the chronic stage in aged rats. Chronically facilitating the synthesis of pain-related molecules in nociceptive DRG neurons is a novel mechanism underpinning the contribution of PGE2. Copyright 2008 Elsevier Inc. All rights reserved.

Cyclooxygenase-2 inhibitor blocks the production of West Nile virus-induced neuroinflammatory markers in astrocytes.

PubMed

Verma, Saguna; Kumar, Mukesh; Nerurkar, Vivek R

2011-03-01

Inflammatory immune responses triggered initially to clear West Nile virus (WNV) infection later become detrimental and contribute to the pathological processes such as blood-brain barrier (BBB) disruption and neuronal death, thus complicating WNV-associated encephalitis (WNVE). It has been demonstrated previously that WNV infection in astrocytes results in induction of multiple matrix metalloproteinases (MMPs), which mediate BBB disruption. Cyclooxygenase (COX) enzymes and their product, prostaglandin E2 (PGE2), modulate neuroinflammation and regulate the production of multiple inflammatory molecules including MMPs. Therefore, this study determined and characterized the pathophysiological consequences of the expression of COX enzymes in human brain cortical astrocytes (HBCAs) following WNV infection. Whilst COX-1 mRNA expression did not change, WNV infection significantly induced RNA and protein expression of COX-2 in HBCAs. Similarly, PGE2 production was also enhanced significantly in infected HBCAs and was blocked in the presence of the COX-2-specific inhibitor NS-398, thus suggesting that COX-2, and not COX-1, was the source of the increased PGE2. Treatment of infected HBCAs with NS-398 attenuated the expression of MMP-1, -3 and -9 in a dose-dependent manner. Similarly, expression of interleukin-1β, -6 and -8, which were markedly elevated in infected HBCAs, exhibited a significant reduction in their levels in the presence of NS-398. These results provide direct evidence that WNV-induced COX-2/PGE2 is involved in modulating the expression of multiple neuroinflammatory mediators, thereby directly linking COX-2 with WNV disease pathogenesis. The ability of COX-2 inhibitors to modulate WNV-induced COX-2 and PGE2 signalling warrants further investigation in an animal model as a potential approach for clinical management of neuroinflammation associated with WNVE.

Fluid shear stress induces upregulation of COX-2 and PGI2 release in endothelial cells via a pathway involving PECAM-1, PI3K, FAK, and p38.

PubMed

Russell-Puleri, Sparkle; Dela Paz, Nathaniel G; Adams, Diana; Chattopadhyay, Mitali; Cancel, Limary; Ebong, Eno; Orr, A Wayne; Frangos, John A; Tarbell, John M

2017-03-01

Vascular endothelial cells play an important role in the regulation of vascular function in response to mechanical stimuli in both healthy and diseased states. Prostaglandin I 2 (PGI 2 ) is an important antiatherogenic prostanoid and vasodilator produced in endothelial cells through the action of the cyclooxygenase (COX) isoenzymes COX-1 and COX-2. However, the mechanisms involved in sustained, shear-induced production of COX-2 and PGI 2 have not been elucidated but are determined in the present study. We used cultured endothelial cells exposed to steady fluid shear stress (FSS) of 10 dyn/cm 2 for 5 h to examine shear stress-induced induction of COX-2/PGI 2 Our results demonstrate the relationship between the mechanosensor platelet endothelial cell adhesion molecule-1 (PECAM-1) and the intracellular mechanoresponsive molecules phosphatidylinositol 3-kinase (PI3K), focal adhesion kinase (FAK), and mitogen-activated protein kinase p38 in the FSS induction of COX-2 expression and PGI 2 release. Knockdown of PECAM-1 (small interference RNA) expression inhibited FSS-induced activation of α 5 β 1 -integrin, upregulation of COX-2, and release of PGI 2 in both bovine aortic endothelial cells (BAECs) and human umbilical vein endothelial cells (HUVECs). Furthermore, inhibition of the PI3K pathway (LY294002) substantially inhibited FSS activation of α 5 β 1 -integrin, upregulation of COX-2 gene and protein expression, and release of PGI 2 in BAECs. Inhibition of integrin-associated FAK (PF573228) and MAPK p38 (SB203580) also inhibited the shear-induced upregulation of COX-2. Finally, a PECAM-1 -/- mouse model was characterized by reduced COX-2 immunostaining in the aorta and reduced plasma PGI 2 levels compared with wild-type mice, as well as complete inhibition of acute flow-induced PGI 2 release compared with wild-type animals. NEW & NOTEWORTHY In this study we determined the major mechanotransduction pathway by which blood flow-driven shear stress activates

Fluid shear stress induces upregulation of COX-2 and PGI2 release in endothelial cells via a pathway involving PECAM-1, PI3K, FAK, and p38

PubMed Central

Russell-Puleri, Sparkle; dela Paz, Nathaniel G.; Adams, Diana; Chattopadhyay, Mitali; Cancel, Limary; Ebong, Eno; Orr, A. Wayne; Frangos, John A.

2017-01-01

Vascular endothelial cells play an important role in the regulation of vascular function in response to mechanical stimuli in both healthy and diseased states. Prostaglandin I2 (PGI2) is an important antiatherogenic prostanoid and vasodilator produced in endothelial cells through the action of the cyclooxygenase (COX) isoenzymes COX-1 and COX-2. However, the mechanisms involved in sustained, shear-induced production of COX-2 and PGI2 have not been elucidated but are determined in the present study. We used cultured endothelial cells exposed to steady fluid shear stress (FSS) of 10 dyn/cm2 for 5 h to examine shear stress-induced induction of COX-2/PGI2. Our results demonstrate the relationship between the mechanosensor platelet endothelial cell adhesion molecule-1 (PECAM-1) and the intracellular mechanoresponsive molecules phosphatidylinositol 3-kinase (PI3K), focal adhesion kinase (FAK), and mitogen-activated protein kinase p38 in the FSS induction of COX-2 expression and PGI2 release. Knockdown of PECAM-1 (small interference RNA) expression inhibited FSS-induced activation of α5β1-integrin, upregulation of COX-2, and release of PGI2 in both bovine aortic endothelial cells (BAECs) and human umbilical vein endothelial cells (HUVECs). Furthermore, inhibition of the PI3K pathway (LY294002) substantially inhibited FSS activation of α5β1-integrin, upregulation of COX-2 gene and protein expression, and release of PGI2 in BAECs. Inhibition of integrin-associated FAK (PF573228) and MAPK p38 (SB203580) also inhibited the shear-induced upregulation of COX-2. Finally, a PECAM-1−/− mouse model was characterized by reduced COX-2 immunostaining in the aorta and reduced plasma PGI2 levels compared with wild-type mice, as well as complete inhibition of acute flow-induced PGI2 release compared with wild-type animals. NEW & NOTEWORTHY In this study we determined the major mechanotransduction pathway by which blood flow-driven shear stress activates cyclooxygenase-2 (COX-2

Cyclooxygenase 2 inhibition suppresses tubuloglomerular feedback: roles of thromboxane receptors and nitric oxide

PubMed Central

Araujo, Magali; Welch, William J.

2009-01-01

Thromboxane (TxA2) and nitric oxide (NO) are potent vasoactive autocoids that modulate tubuloglomerular feedback (TGF). Each is produced in the macula densa (MD) by cyclooxygenase-2 (COX-2) and neuronal nitric oxide synthase (nNOS), respectively. Both enzymes are similarly regulated in the MD and their interaction may be an important factor in the regulation of TGF and glomerular filtration rate. We tested the hypothesis that TGF is modified by the balance between MD nNOS-dependent NO and MD COX-2-dependent TxA2. We measured maximal TGF during perfusion of the loop of Henle (LH) by continuous recording of the proximal tubule stopped flow pressure response to LH perfusion of artificial tubular fluid (ATF) at 0 and 40 nl/min. The response to inhibitors of COX-1 (SC-560), COX-2 [parecoxib (Pxb)], and nNOS (l-NPA) added to the ATF solution was measured in separate nephrons. COX-2 inhibition with Pxb reduced TGF by 46% (ATF + vehicle vs. ATF + Pxb), whereas COX-1 inhibition with SC-560 reduced TGF by only 23%. Pretreatment with intravenous infusion of SQ-29,548, a selective thromboxone/PGH2 receptor (TPR) antagonist, blocked all of the SC-560 effect on TGF, suggesting that this effect was due to activation of TPR. However, SQ-29,548 only partially diminished the effect of Pxb (−66%). Specific inhibition of nNOS with l-NPA increased TGF, as expected. However, the ability of Pxb to reduce TGF was significantly impaired with comicroperfusion of l-NPA. These data suggest that COX-2 modulates TGF by two proconstrictive actions: generation of TxA2 acting on TPR and by simultaneous reduction of NO. PMID:19144694

Myeloid Cell COX-2 deletion reduces mammary tumor growth through enhanced cytotoxic T-lymphocyte function

PubMed Central

Chen, Edward P.; Markosyan, Nune; Connolly, Emma; Lawson, John A.; Li, Xuanwen; Grant, Gregory R.; Grosser, Tilo; FitzGerald, Garret A.; Smyth, Emer M.

2014-01-01

Cyclooxygenase-2 (COX-2) expression is associated with poor prognosis across a range of human cancers, including breast cancer. The contribution of tumor cell-derived COX-2 to tumorigenesis has been examined in numerous studies; however, the role of stromal-derived COX-2 is ill-defined. Here, we examined how COX-2 in myeloid cells, an immune cell subset that includes macrophages, influences mammary tumor progression. In mice engineered to selectively lack myeloid cell COX-2 [myeloid-COX-2 knockout (KO) mice], spontaneous neu oncogene-induced tumor onset was delayed, tumor burden reduced, and tumor growth slowed compared with wild-type (WT). Similarly, growth of neu-transformed mammary tumor cells as orthotopic tumors in immune competent syngeneic myeloid-COX-2 KO host mice was reduced compared with WT. By flow cytometric analysis, orthotopic myeloid-COX-2 KO tumors had lower tumor-associated macrophage (TAM) infiltration consistent with impaired colony stimulating factor-1-dependent chemotaxis by COX-2 deficient macrophages in vitro. Further, in both spontaneous and orthotopic tumors, COX-2-deficient TAM displayed lower immunosuppressive M2 markers and this was coincident with less suppression of CD8+ cytotoxic T lymphocytes (CTLs) in myeloid-COX-2 KO tumors. These studies suggest that reduced tumor growth in myeloid-COX-2 KO mice resulted from disruption of M2-like TAM function, thereby enhancing T-cell survival and immune surveillance. Antibody-mediated depletion of CD8+, but not CD4+ cells, restored tumor growth in myeloid-COX-2 KO to WT levels, indicating that CD8+ CTLs are dominant antitumor effectors in myeloid-COX-2 KO mice. Our studies suggest that inhibition of myeloid cell COX-2 can potentiate CTL-mediated tumor cytotoxicity and may provide a novel therapeutic approach in breast cancer therapy. PMID:24590894

Cyclooxygenase-2 expression and clinical parameters in laryngeal squamous cell carcinoma, vocal fold nodule, and laryngeal atypical hyperplasia.

PubMed

Sayar, Cağdaş; Sayar, Hamide; Özdemir, Süleyman; Selçuk, Tahsin; Görgülü, Orhan; Akbaş, Yücel; Kemal Olgun, Mustafa

2013-01-01

The diagnostic role of cyclooxygenase-2 (COX-2) expression in laryngeal atypical hyperplasia, vocal fold nodule, and laryngeal squamous cell carcinoma was examined. Specimens obtained from patients diagnosed with vocal fold nodule (n = 35), atypical hyperplasia (n = 35), laryngeal squamous cell carcinoma (n = 35), and clinical parameters were evaluated retrospectively. Although no staining was observed in patients with vocal fold nodules, staining was noted in laryngeal atypical hyperplasia and squamous cell carcinoma. The percentage of COX-2 staining was the highest in the carcinoma group. It was determined that COX-2 staining was significantly associated with laryngeal squamous cell carcinoma. It should be noted that overexpression of COX-2, a potentially important factor in the evolution of carcinogenesis in precancerous lesions, might be an indicator of the development of carcinoma. Copyright © 2012 Wiley Periodicals, Inc.

Angiotensin II-AT1-receptor signaling is necessary for cyclooxygenase-2-dependent postnatal nephron generation.

PubMed

Frölich, Stefanie; Slattery, Patrick; Thomas, Dominique; Goren, Itamar; Ferreiros, Nerea; Jensen, Boye L; Nüsing, Rolf M

2017-04-01

Deletion of cyclooxygenase-2 (COX-2) causes impairment of postnatal kidney development. Here we tested whether the renin angiotensin system contributes to COX-2-dependent nephrogenesis in mice after birth and whether a rescue of impaired renal development and function in COX-2 -/- mice was achievable. Plasma renin concentration in mouse pups showed a birth peak and a second peak around day P8 during the first 10 days post birth. Administration of the angiotensin II receptor AT1 antagonist telmisartan from day P1 to P3 did not result in cortical damage. However, telmisartan treatment from day P3 to P8, the critical time frame of renal COX-2 expression, led to hypoplastic glomeruli, a thinned subcapsular cortex and maturational arrest of superficial glomeruli quite similar to that observed in COX-2 -/- mice. In contrast, AT2 receptor antagonist PD123319 was without any effect on renal development. Inhibition of the renin angiotensin system by aliskiren and enalapril caused similar glomerular defects as telmisartan. Administration of the AT1 receptor agonist L162313 to COX-2 -/- pups improved kidney growth, ameliorated renal defects, but had no beneficial effect on reduced cortical mass. L162313 rescued impaired renal function by reducing serum urea and creatinine and mitigated pathologic albumin excretion. Moreover, glomerulosclerosis in the kidneys of COX-2 -/- mice was reduced. Thus, angiotensin II-AT1-receptor signaling is necessary for COX-2-dependent normal postnatal nephrogenesis and maturation. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Feedback amplification of fibrosis through matrix stiffening and COX-2 suppression

PubMed Central

Liu, Fei; Mih, Justin D.; Shea, Barry S.; Kho, Alvin T.; Sharif, Asma S.; Tager, Andrew M.

2010-01-01

Tissue stiffening is a hallmark of fibrotic disorders but has traditionally been regarded as an outcome of fibrosis, not a contributing factor to pathogenesis. In this study, we show that fibrosis induced by bleomycin injury in the murine lung locally increases median tissue stiffness sixfold relative to normal lung parenchyma. Across this pathophysiological stiffness range, cultured lung fibroblasts transition from a surprisingly quiescent state to progressive increases in proliferation and matrix synthesis, accompanied by coordinated decreases in matrix proteolytic gene expression. Increasing matrix stiffness strongly suppresses fibroblast expression of COX-2 (cyclooxygenase-2) and synthesis of prostaglandin E2 (PGE2), an autocrine inhibitor of fibrogenesis. Exogenous PGE2 or an agonist of the prostanoid EP2 receptor completely counteracts the proliferative and matrix synthetic effects caused by increased stiffness. Together, these results demonstrate a dominant role for normal tissue compliance, acting in part through autocrine PGE2, in maintaining fibroblast quiescence and reveal a feedback relationship between matrix stiffening, COX-2 suppression, and fibroblast activation that promotes and amplifies progressive fibrosis. PMID:20733059

Methotrexate as a preferential cyclooxygenase 2 inhibitor in whole blood of patients with rheumatoid arthritis.

PubMed

Mello, S B; Barros, D M; Silva, A S; Laurindo, I M; Novaes, G S

2000-05-01

To investigate the regulation of whole-blood cyclooxygenase-1 and -2 (COX-2 and COX-1) activities by methotrexate (MTX) in rheumatoid arthritis (RA) patients. Whole blood was withdrawn from nine healthy volunteers, 12 RA patients treated with MTX (RA/MTX) and six RA patients treated with chloroquine (RA/CQ). COX-1 activity was quantified as platelet thromboxane B(2) production in unstimulated blood and COX-2 activity was measured as prostaglandin E(2) (PGE(2)) production in whole blood stimulated with LPS. Thromboxane B(2) and PGE(2) were measured by radioimmunoassay. We studied the drug effect in vitro by direct incubation of MTX with blood obtained from normal donors. Ex vivo assays were performed with blood collected from RA/MTX and RA/CQ patients. The influence of serum factors on enzyme activities was analysed in blood collected from normal donors and incubated with RA/MTX, autologous or heterologous serum. In vitro assays showed no direct action of MTX on the activity of either enzyme. Assays performed with blood from RA/MTX patients showed preferential inhibition of COX-2 activity (PGE(2) = 10.11 +/- 2.42 ng/ml) when compared with blood of normal donors (PGE(2) = 37.7 +/- 4.36 ng/ml; P = 0.001). Inhibition of COX-2 activity was also observed when blood of normal donors was co-incubated with RA/MTX serum. Our results clearly show that the anti-inflammatory action of low-dose MTX is partly mediated by a serum factor induced by MTX or a MTX metabolite that preferentially inhibits the activity of COX-2.

Diabetes Upregulation of Cyclooxygenase 2 Contributes to Altered Coronary Reactivity After Cardiac Surgery.

PubMed

Feng, Jun; Anderson, Kelsey; Singh, Arun K; Ehsan, Afshin; Mitchell, Hunter; Liu, Yuhong; Sellke, Frank W

2017-08-01

We hypothesized that upregulation of inducible cyclooxygenase 2 (COX-2) contributes to altered coronary arteriolar reactivity early after cardioplegic arrest and cardiopulmonary bypass (CP/CPB) in patients with diabetes mellitus who are undergoing cardiac surgery. The right atrial tissue samples of nondiabetes (ND), controlled diabetes (CDM), and uncontrolled diabetes (UDM) patients undergoing cardiac surgery were harvested before and after CP/CPB. Coronary arterioles (80 to 150 μm) were dissected from the harvested atrial tissue samples, cannulated, and pressurized. The changes in diameter were measured with video microscopy. The protein expression and localization of COX-1 and COX-2 were assayed by Western blot and immunohistochemistry. In the diabetes arterioles, bradykinin-induced relaxation response was inhibited by the selective COX-2 inhibitor NS398 at baseline (p < 0.05). This effect was more pronounced in UDM arterioles than CDM (p < 0.05). After CP/CPB, bradykinin-induced responses in all groups were inhibited by NS398, but this effect was more pronounced in the UDM patients (p < 0.05). The intensities of COX-2 staining of coronary arterioles and COX-2 protein levels in myocardium were higher in diabetes than nondiabetes at baseline (p < 0.05). The post-CP/CPB protein levels of the inducible COX-2 were significantly increased compared with pre-CP/CPB values in all groups (p < 0.05), whereas this increase was higher with diabetes than with ND (p < 0.05). Furthermore, these effects were more profound in UDM than CDM (p < 0.05). Diabetes and CP/CPB are associated with upregulation in COX-2 expression in human coronary vasculature. Upregulation of COX-2 expression may contribute to bradykinin-induced coronary arteriolar relaxation in diabetic patients undergoing cardiac surgery. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Prospective performance evaluation of selected common virtual screening tools. Case study: Cyclooxygenase (COX) 1 and 2.

PubMed

Kaserer, Teresa; Temml, Veronika; Kutil, Zsofia; Vanek, Tomas; Landa, Premysl; Schuster, Daniela

2015-01-01

Computational methods can be applied in drug development for the identification of novel lead candidates, but also for the prediction of pharmacokinetic properties and potential adverse effects, thereby aiding to prioritize and identify the most promising compounds. In principle, several techniques are available for this purpose, however, which one is the most suitable for a specific research objective still requires further investigation. Within this study, the performance of several programs, representing common virtual screening methods, was compared in a prospective manner. First, we selected top-ranked virtual screening hits from the three methods pharmacophore modeling, shape-based modeling, and docking. For comparison, these hits were then additionally predicted by external pharmacophore- and 2D similarity-based bioactivity profiling tools. Subsequently, the biological activities of the selected hits were assessed in vitro, which allowed for evaluating and comparing the prospective performance of the applied tools. Although all methods performed well, considerable differences were observed concerning hit rates, true positive and true negative hits, and hitlist composition. Our results suggest that a rational selection of the applied method represents a powerful strategy to maximize the success of a research project, tightly linked to its aims. We employed cyclooxygenase as application example, however, the focus of this study lied on highlighting the differences in the virtual screening tool performances and not in the identification of novel COX-inhibitors. Copyright © 2015 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

Cyclo-oxygenase 2 expression is associated with angiogenesis and lymph node metastasis in human breast cancer.

PubMed

Costa, C; Soares, R; Reis-Filho, J S; Leitão, D; Amendoeira, I; Schmitt, F C

2002-06-01

Cyclo-oxygenases 1 and 2 (COX-1 and COX-2) are key enzymes in prostaglandin biosynthesis. COX-2 is induced by a wide variety of stimuli, and present during inflammation. COX-2 overexpression has been observed in colon, head and neck, lung, prostate, stomach, and breast cancer. In colon and gastric cancer, COX-2 expression was associated with angiogenesis. The aim of this study was to determine the relation between COX-2 expression and angiogenesis in breast cancer, and to correlate the expression of this enzyme with classic clinicopathological parameters. COX-2 expression was investigated by immunohistochemistry and western blotting analysis. The expression of COX-2 was then related to age, histological grade, nodal status, oestrogen receptor status, p53 expression,c-erb-B2 overexpression, mitotic counts, MIB-1 labelling index, apoptotic index, sialyl-Tn expression, transforming growth factor alpha expression, microvessel density, and disease free survival in 46 patients with invasive ductal breast carcinoma. By means of immunohistochemistry, COX-2 expression was detected in eight of the 46 carcinomas studied. Western blotting showed COX-2 protein expression in the same breast tumours, but not in normal adjacent tissues. The density of microvessels immunostained with anti-F-VIII related antigen was significantly higher in patients with COX-2 expression than in those without expression (p = 0.03). In addition, COX-2 was significantly associated with the presence of sialyl-Tn expression (p = 0.02), lymph node metastasis (p = 0.03), a high apoptotic index (p = 0.03), and a short disease free survival (p = 0.03) in univariate analyses. These data suggest that COX-2 expression is associated with angiogenesis, lymph node metastasis, and apoptosis in human breast cancer. Moreover, these results warrant further studies with larger series of patients to confirm the association with short disease free survival in patients with breast cancer.

Inhibition of COX-2 and PGE2 in LPS-stimulated RAW264.7 cells by lonimacranthoide VI, a chlorogenic acid ester saponin

PubMed Central

GUAN, FUQIN; WANG, HAITING; SHAN, YU; CHEN, YU; WANG, MING; WANG, QIZHI; YIN, MIN; ZHAO, YOUYI; FENG, XU; ZHANG, JIANHUA

2014-01-01

Lonimacranthoide VI, first isolated from the flower buds of Lonicera macranthoides in our previous study, is a rare chlorogenic acid ester acylated at C-23 of hederagenin. In the present study, the anti-inflammatory effects of lonimacranthoide VI were studied. Lipopolysaccharides (LPS) induced an inflammatory response through the production of prostaglandin E2 (PGE2), and these levels were reduced when lonimacranthoide VI was pre-administered. Additionally, the mechanism of the anti-inflammatory effects of lonimacranthoide VI was investigated by measuring cyclooxygenase (COX) activity and mRNA expression. The results showed that lonimacranthoide VI inhibited mRNA expression and in vitro activity of COX-2 in a dose-dependent manner, whereas only the higher lonimacranthoide VI concentration possibly reduced COX-1 expression and in vitro activity. Taken together, these results indicate that lonimacranthoide VI is an important anti-inflammatory constituent of Lonicera macranthoides and that the anti-inflammatory effect is attributed to the inhibition of PGE2 production through COX activity and mRNA expression. PMID:25054024

STIM1 Overexpression Promotes Colorectal Cancer Progression, Cell Motility and COX-2 Expression

PubMed Central

Wang, Jaw-Yuan; Sun, Jianwei; Huang, Ming-Yii; Wang, Yu-Shiuan; Hou, Ming-Feng; Sun, Yan; He, Huifang; Krishna, Niveditha; Chiu, Siou-Jin; Lin, Shengchen; Yang, Shengyu; Chang, Wei-Chiao

2014-01-01

Tumor metastasis is the major cause of death among cancer patients, with more than 90% of cancer-related death attributable to the spreading of metastatic cells to secondary organs. Store-operated Ca2+ entry (SOCE) is the predominant Ca2+ entry mechanism in most cancer cells, and STIM1 is the endoplasmic reticulum (ER) Ca2+ sensor for store-operated channels (SOC). Here we reported that the STIM1 was overexpressed in colorectal cancer (CRC) patients. STIM1 overexpression in CRC was significantly associated with tumor size, depth of invasion, lymphnode metastasis status and serum levels of carcinoembryonic antigen. Furthermore, ectopic expression of STIM1 promoted CRC cell motility, while depletion of STIM1 with shRNA inhibited CRC cell migration. Our data further suggested that STIM1 promoted CRC cell migration through increasing the expression of cyclooxygenase-2 (COX-2) and production of prostaglandin E2 (PGE2). Importantly, ectopically expressed COX-2 or exogenous PGE2 were able to rescue migration defect in STIM1 knockdown CRC cells, and inhibition of COX-2 with ibuprofen and indomethacin abrogated STIM1-mediated CRC cell motility. In short, our data provided clinicopathological significance for STIM1 and store-operated Ca2+ entry in CRC progression, and implicated a role for COX-2 in STIM1-mediated CRC metastasis. Our studies also suggested a new approach to inhibit STIM1-mediated metastasis with COX-2 inhibitors. PMID:25381814

Cyclooxygenase 2 gene polymorphisms and chronic periodontitis in a North Indian population: a pilot study

PubMed Central

Daing, Anika; Singh, Sarvendra Vikram; Saimbi, Charanjeet Singh; Khan, Mohammad Akhlaq

2012-01-01

Purpose Cyclooxygenase (COX) enzyme catalyzes the production of prostaglandins, which are important mediators of tissue destruction in periodontitis. Single nucleotide polymorphisms of COX2 enzyme have been associated with increasing susceptibility to inflammatory diseases. The present study evaluates the association of two single nucleotide polymorphisms in COX2 gene (-1195G>A and 8473C>T) with chronic periodontitis in North Indians. Methods Both SNPs and their haplotypes were used to explore the associations between COX2 polymorphisms and chronic periodontitis in 56 patients and 60 controls. Genotyping was done by polymerase chain reaction followed by restriction fragment length polymorphism. Chi-square test and logistic regression analysis were performed for association analysis. Results By the individual genotype analysis, mutant genotypes (GA and AA) of COX2 -1195 showed more than a two fold risk (odds ratio [OR]>2) and COX2 8473 (TC and CC) showed a reduced risk for the disease, but the findings were not statistically significant. Haplotype analysis showed that the frequency of the haplotype AT was higher in the case group and a significant association was found for haplotype AT (OR, 1.79; 95% confidence interval, 1.03 to 3.11; P=0.0370) indicating an association between the AT haplotype of COX2 gene SNPs and chronic periodontitis. Conclusions Individual genotypes of both the SNPs were not associated while haplotype AT was found to be associated with chronic periodontitis in North Indians. PMID:23185695

Specific trans-acting proteins interact with auxiliary RNA polyadenylation elements in the COX-2 3′-UTR

PubMed Central

Hall-Pogar, Tyra; Liang, Songchun; Hague, Lisa K.; Lutz, Carol S.

2007-01-01

Two cyclooxygenase (COX) enzymes, COX-1 and COX-2, are present in human cells. While COX-1 is constitutively expressed, COX-2 is inducible and up-regulated in response to many signals. Since increased transcriptional activity accounts for only part of COX-2 up-regulation, we chose to explore other RNA processing mechanisms in the regulation of this gene. Previously, we showed that COX-2 is regulated by alternative polyadenylation, and that the COX-2 proximal polyadenylation signal contains auxiliary upstream sequence elements (USEs) that are very important in efficient polyadenylation. To explore trans-acting protein factors interacting with these cis-acting RNA elements, we performed pull-down assays with HeLa nuclear extract and biotinylated RNA oligonucleotides representing COX-2 USEs. We identified PSF, p54nrb, PTB, and U1A as proteins specifically bound to the COX-2 USEs. We further explored their participation in polyadenylation using MS2 phage coat protein-MS2 RNA binding site tethering assays, and found that tethering any of these four proteins to the COX-2 USE mutant RNA can compensate for these cis-acting elements. Finally, we suggest that these proteins (p54nrb, PTB, PSF, and U1A) may interact as a complex since immunoprecipitations of the transfected MS2 fusion proteins coprecipitate the other proteins. PMID:17507659

Adenosine up-regulates cyclooxygenase-2 in human granulocytes: impact on the balance of eicosanoid generation.

PubMed

Pouliot, Marc; Fiset, Marie-Elaine; Massé, Mireille; Naccache, Paul H; Borgeat, Pierre

2002-11-01

Polymorphonuclear neutrophils (granulocytes; PMNs) are often the first blood cells to migrate toward inflammatory lesions to perform host defense functions. PMNs respond to specific stimuli by releasing several factors and generate lipid mediators of inflammation from the 5-lipoxygenase and the inducible cyclooxygenase (COX)-2 pathways. In view of adenosine's anti-inflammatory properties and suppressive impact on the 5-lipoxygenase pathway, we addressed in this study the impact of this autacoid on the COX-2 pathway. We observed that adenosine up-regulates the expression of the COX-2 enzyme and mRNA. Production of PGE(2) in response to exogenous arachidonic acid was also increased by adenosine and correlated with COX-2 protein levels. The potentiating effect of adenosine on COX-2 could be mimicked by pharmacological increases of intracellular cAMP levels, involving the latter as a putative second messenger for the up-regulation of COX-2 by adenosine. Specific COX-2 inhibitors were used to confirm the predominant role of the COX-2 isoform in the formation of prostanoids by stimulated PMNs. Withdrawal of extracellular adenosine strikingly emphasized the inhibitory potential of PGE(2) on leukotriene B(4) formation and involved the EP(2) receptor subtype in this process. Thus, adenosine may promote a self-limiting regulatory process through the increase of PGE(2) generation, which may result in the inhibition of PMN functions. This study identifies a new aspect of the anti-inflammatory properties of adenosine in leukocytes, introducing the concept that this autacoid may exert its immunomodulatory activities in part by modifying the balance of lipid mediators generated by PMNs.

Bioassay-guided supercritical fluid extraction of cyclooxygenase-2 inhibiting substances in Plantago major L.

PubMed

Stenholm, A; Göransson, U; Bohlin, L

2013-02-01

Selective extraction of plant materials is advantageous for obtaining extracts enriched with desired constituents, thereby reducing the need for subsequent chromatography purification. Such compounds include three cyclooxygenase-2 (COX-2) inhibitory substances in Plantago major L. targeted in this investigation: α-linolenic acid (α-LNA) (18:3 ω-3) and the triterpenic acids ursolic acid and oleanolic acid. To investigate the scope for tuning the selectivity of supercritical fluid extraction (SFE) using bioassay guidance, and Soxhlet extraction with dichloromethane as solvent as a reference technique, to optimise yields of these substances. Extraction parameters were varied to optimise extracts' COX-2/COX-1 inhibitory effect ratios. The crude extracts were purified initially using a solid phase extraction (SPE) clean-up procedure and the target compounds were identified with GC-MS, LC-ESI-MS and LC-ESI-MS² using GC-FID for quantification. α-LNA was preferentially extracted in dynamic mode using unmodified carbon dioxide at 40°C and 172 bar, at a 0.04% (w/w) yield with a COX-2/COX-1 inhibitory effect ratio of 1.5. Ursolic and oleanolic acids were dynamically extracted at 0.25% and 0.06% yields, respectively, with no traces of (α-LNA) and a COX-2/COX-1-inhibitory effect ratio of 1.1 using 10% (v/v) ethanol as polar modifier at 75°C and 483 bar. The Soxhlet extracts had ursolic acid, oleanolic acid and αLNA yields up to 1.36%, 0.34% and 0.15%, respectively, with a COX-2/COX-1 inhibitory effect ratio of 1.2. The target substances can be extracted selectively by bioassay guided optimisation of SFE conditions. Copyright © 2012 John Wiley & Sons, Ltd.

Tilapia Hepcidin 2-3 Peptide Modulates Lipopolysaccharide-induced Cytokines and Inhibits Tumor Necrosis Factor-α through Cyclooxygenase-2 and Phosphodiesterase 4D*

PubMed Central

Rajanbabu, Venugopal; Pan, Chieh-Yu; Lee, Shang-Chun; Lin, Wei-Ju; Lin, Ching-Chun; Li, Chung-Leung; Chen, Jyh-Yih

2010-01-01

The antimicrobial peptide, tilapia hepcidin (TH) 2-3, belongs to the hepcidin family, and its antibacterial function has been reported. Here, we examined the TH2-3-mediated regulation of proinflammatory cytokines in bacterial endotoxin lipopolysaccharide (LPS)-stimulated mouse macrophages. The presence of TH2-3 in LPS-stimulated cells reduced the amount of tumor necrosis factor (TNF)-α secretion. From a microarray, real-time polymerase chain reaction (PCR), and cytokine array studies, we showed down-regulation of the proinflammatory cytokines TNF-α, interleukin (IL)-1α, IL-1β, IL-6, and the prostaglandin synthesis gene, cyclooxygenase (COX)-2, by TH2-3. Studies with the COX-2-specific inhibitor, melaxicam, and with COX-2-overexpressing cells demonstrated the positive regulation of TNF-α and negative regulation of cAMP degradation-specific phosphodiesterase (PDE) 4D by COX-2. In LPS-stimulated cells, TH2-3 acts like melaxicam and down-regulates COX-2 and up-regulates PDE4D. The reduction in intracellular cAMP by TH2-3 or melaxicam in LPS-stimulated cells supports the negative regulation of PDE4D by COX-2 and TH2-3. This demonstrates that the inhibition of COX-2 is among the mechanisms through which TH2-3 controls TNF-α release. At 1 h after treatment, the presence of TH2-3 in LPS-stimulated cells had suppressed the induction of pERK1/2 and prevented the LPS-stimulated nuclear accumulation of NF-κB family proteins of p65, NF-κB2, and c-Rel. In conclusion, TH2-3 inhibits TNF-α and other proinflammatory cytokines through COX-2-, PDE4D-, and pERK1/2-dependent mechanisms. PMID:20675368

COX-2 expression in canine anal sac adenocarcinomas and in non-neoplastic canine anal sacs.

PubMed

Knudsen, C S; Williams, A; Brearley, M J; Demetriou, J L

2013-09-01

Anal sac adenocarcinoma (ASAC) is a clinically significant canine neoplasm characterized by early lymphatic invasion. Up-regulation of cyclooxygenase isoform 2 (COX-2) has been confirmed in several animal and human neoplastic tissues. The aim of the current study was primarily to evaluate COX-2 expression in canine ASAC and compare it to COX-2 expression in non-neoplastic canine anal sac tissue using immunohistochemistry with scoring for percentage positivity and intensity. Twenty-five ASAC samples and 22 normal anal sacs were available for evaluation. All canine ASAC samples and the normal anal sac tissues stained positively for COX-2. However, while normal anal sac tissue showed strong staining of the ductal epithelial cells, ASAC samples showed staining of the neoplastic glandular epithelial cells, with varying percentage positivity and intensity between ASAC samples. COX-2 immunoreactivity of ASAC samples was of low intensity in 52% and high in 12% of the cases; the remaining samples were of intermediate intensity. Seventy-six per cent of the ASAC had over 50% of the neoplastic glandular cells staining positive. These results confirm that COX-2 is expressed in the neoplastic glandular epithelial cells in canine ASAC and suggest a potential role for COX-2 inhibitors in the management of ASAC. Furthermore, the results indicate that COX-2 is expressed in ductal epithelial cells of the normal anal sac. Copyright © 2013 Elsevier Ltd. All rights reserved.

Radiation induced COX-2 expression and mutagenesis at non-targeted lung tissues of gpt delta transgenic mice

PubMed Central

Chai, Y; Calaf, G M; Zhou, H; Ghandhi, S A; Elliston, C D; Wen, G; Nohmi, T; Amundson, S A; Hei, T K

2013-01-01

Background: Although radiation-induced bystander effects have been confirmed using a variety of endpoints, the mechanism(s) underlying these effects are not well understood, especially for in vivo study. Methods: A 1-cm2 area (1 cm × 1 cm) in the lower abdominal region of gpt delta transgenic mice was irradiated with 5 Gy of 300 keV X-rays, and changes in out-of-field lung and liver were observed. Results: Compared with sham-treated controls, the Spi− mutation frequency increased 2.4-fold in non-targeted lung tissues at 24 h after partial body irradiation (PBIR). Consistent with dramatic Cyclooxygenase 2 (COX-2) induction in the non-targeted bronchial epithelial cells, increasing levels of prostaglandin, together with 8-hydroxydeoxyguanosine, in the out-of-field lung tissues were observed after PBIR. In addition, DNA double-strand breaks and apoptosis were induced in bystander lung tissues after PBIR. Conclusion: The PBIR induces DNA damage and mutagenesis in non-targeted lung tissues, especially in bronchial epithelial cells, and COX-2 has an essential role in bystander mutagenesis. PMID:23321513

Soman increases neuronal COX-2 levels: possible link between seizures and protracted neuronal damage.

PubMed

Angoa-Pérez, Mariana; Kreipke, Christian W; Thomas, David M; Van Shura, Kerry E; Lyman, Megan; McDonough, John H; Kuhn, Donald M

2010-12-01

Nerve agent-induced seizures cause neuronal damage in brain limbic and cortical circuits leading to persistent behavioral and cognitive deficits. Without aggressive anticholinergic and benzodiazepine therapy, seizures can be prolonged and neuronal damage progresses for extended periods of time. The objective of this study was to determine the effects of the nerve agent soman on expression of cyclooxygenase-2 (COX-2), the initial enzyme in the biosynthetic pathway of the proinflammatory prostaglandins and a factor that has been implicated in seizure initiation and propagation. Rats were exposed to a toxic dose of soman and scored behaviorally for seizure intensity. Expression of COX-2 was determined throughout brain from 4h to 7 days after exposure by immunohistochemistry and immunoblotting. Microglial activation and astrogliosis were assessed microscopically over the same time-course. Soman increased COX-2 expression in brain regions known to be damaged by nerve agents (e.g., hippocampus, amygdala, piriform cortex and thalamus). COX-2 expression was induced in neurons, and not in microglia or astrocytes, and remained elevated through 7 days. The magnitude of COX-2 induction was correlated with seizure intensity. COX-1 expression was not changed by soman. Increased expression of neuronal COX-2 by soman is a late-developing response relative to other signs of acute physiological distress caused by nerve agents. COX-2-mediated production of prostaglandins is a consequence of the seizure-induced neuronal damage, even after survival of the initial cholinergic crisis is assured. COX-2 inhibitors should be considered as adjunct therapy in nerve agent poisoning to minimize nerve agent-induced seizure activity. Published by Elsevier B.V.

Neuronal overexpression of cyclooxygenase-2 does not alter the neuroinflammatory response during brain innate immune activation.

PubMed

Aid, Saba; Parikh, Nishant; Palumbo, Sara; Bosetti, Francesca

2010-07-12

Neuroinflammation is a critical component in the progression of several neurological and neurodegenerative diseases and cyclooxygenases (COX)-1 and -2 are key regulators of innate immune responses. We recently demonstrated that COX-1 deletion attenuates, whereas COX-2 deletion enhances, the neuroinflammatory response, blood-brain barrier permeability and leukocyte recruitment during lipopolysaccharide (LPS)-induced innate immune activation. Here, we used transgenic mice, which overexpressed human COX-2 via neuron-specific Thy-1 promoter (TgCOX-2), causing elevated prostaglandins (PGs) levels. We tested whether neuronal COX-2 overexpression affects the glial response to a single intracerebroventricular injection of LPS, which produces a robust neuroinflammatory reaction. Relative to non-transgenic controls (NTg), 7 month-old TgCOX-2 did not show any basal neuroinflammation, as assessed by gene expression of markers of inflammation and oxidative stress, neuronal damage, as assessed by Fluoro-JadeB staining, or systemic inflammation, as assessed by plasma levels of IL-1beta and corticosterone. Twenty-four hours after LPS injection, all mice showed increased microglial activation, as indicated by Iba1 immunostaining, neuronal damage, mRNA expression of cytokines (TNF-alpha, IL-6), reactive oxygen expressing enzymes (iNOS and NADPH oxidase subunits), endogenous COX-2, cPLA(2) and mPGES-1, and hippocampal and cortical IL-1beta levels. However, the increases were similar in TgCOX-2 and NTg. In NTg, LPS increased brain PGE(2) to the levels observed in TgCOX-2. These results suggest that PGs derived from neuronal COX-2 do not play a role in the neuroinflammatory response to acute activation of brain innate immunity. This is likely due to the direct effect of LPS on glial rather than neuronal cells. Published by Elsevier Ireland Ltd.

Flaxseed oil increases aortic reactivity to phenylephrine through reactive oxygen species and the cyclooxygenase-2 pathway in rats

PubMed Central

2014-01-01

Background Flaxseed oil has the highest concentration of omega-3 α-linolenic acid, which has been associated with cardiovascular benefit. However, the mechanism underlying the vascular effects induced through flaxseed oil is not well known. Thus, in the present study, we investigated the effects of flaxseed oil on vascular function in isolated rat aortic rings. Methods Wistar rats were treated daily with flaxseed oil or a control (mineral oil) intramuscular (i.m.) for fifteen days. Isolated aortic segments were used to evaluate cyclooxygenase-2 (COX-2) protein expression, superoxide anion levels and vascular reactivity experiments. Results Flaxseed oil treatment increased the vasoconstrictor response of aortic rings to phenylephrine. Endothelium removal increased the response to phenylephrine in aortic segments isolated from both groups, but the effect was smaller in the treated group. L-NAME incubation similarly increased the phenylephrine response in segments from both groups. The TXA2 synthase inhibitor furegrelate, the selective COX-2 inhibitor NS 398, the TP receptor antagonist SQ 29.548, the reactive oxygen species (ROS) scavenger apocynin, the superoxide anion scavengers tiron and the phospholipase A2 inhibitor dexamethasone partially reversed the flaxseed oil-induced increase in reactivity to phenylephrine. Conclusions These findings suggest that flaxseed oil treatment increased vascular reactivity to phenylephrine through an increase in ROS production and COX-2-derived TXA2 production. The results obtained in the present study provide new insight into the effects of flaxseed oil treatment (i.m.) on vascular function. PMID:24993607

Endothelin-1 increases expression of cyclooxygenase-2 and production of interlukin-8 in hunan pulmonary epithelial cells.

PubMed

Peng, Hong; Chen, Ping; Cai, Ying; Chen, Yan; Wu, Qing-Hua; Li, Yun; Zhou, Rui; Fang, Xiang

2008-03-01

Inducible cyclooxygenase (COX-2) and inflammatory cytokines play important roles in inflammatory processes of chronic obstructive pulmonary disease (COPD). Endothelin-1 (ET-1) might be also involved in the pathophysilogical processes in COPD. In the present study, we determined whether ET-1 could regulate the expression of COX-2 and alter the production of interleukin-8 (IL-8) in human pulmonary epithelial cells (A549). Induced sputum samples were collected from 13 stable COPD patients and 14 healthy subjects. The COX-2 protein, ET-1, PGE(2) and IL-8 in these sputum samples were analyzed. A549 cells were incubated with ET-1 in the presence or absence of celecoxib, a selective COX-2 inhibitor. The expression of COX-2 protein in the cell and the amounts of PGE(2) and IL-8 in the medium were measured. The levels of COX-2 protein, ET-1, PGE(2) and IL-8 were significantly increased in induced sputum from COPD patients when compared to healthy subjects. ET-1 increased the expression of COX-2 protein, as well as the production of PGE(2) in A549 cells. Increased production of PGE(2) was inhibited by celecoxib. ET-1 also increased the production of IL-8. Interestingly, ET-1-induced production of IL-8 was also inhibited by celecoxib. These findings indicate that ET-1 plays important roles in regulating COX-2 expression and production of IL-8 in A549 cells. ET-1 mediated production of IL-8 is likely through a COX-2-dependent mechanism.

Anti-tumor effect and mechanism of cyclooxygenase-2 inhibitor through matrix metalloproteinase 14 pathway in PANC-1 cells.

PubMed

Li, Siyuan; Gu, Zhuoyu; Xiao, Zhiwei; Zhou, Ting; Li, Jun; Sun, Kan

2015-01-01

To investigate whether celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, can attenuate proliferation, migration, invasion and MMP-14 expression in pancreatic cancer cells PANC-1 and the possible anti-tumor mechanism of celecoxib. Human pancreatic cancer cell line PANC-1 cells were treated with diverse concentrations of celecoxib (20, 60, 100 μmol/L). Cell proliferation, invasion and migration capabilities were measured by MTT colorimetry, transwell invasion assay, and scratch assay separately. At the same time, the protein expression of COX-2 and MMP-14 was assessed by ELISA. The capabilities of proliferation, invasion and migration in PANC-1 cells were attenuated in a concentration-dependent manner after treated with celecoxib, followed by the down-regulation of the protein expression of COX-2 and MMP-14. In addition, MMP-14 expression was significantly positively correlated with COX-2 expression. COX-2 inhibitor celecoxib can inhibit the proliferation, invasion and migration of PANC-1 cells via down-regulating the expression of MMP-14 in a concentration-dependent manner, thus contributing to its anti-tumor effect in pancreatic cancer.

Breast cancer cell cyclooxygenase-2 expression alters extracellular matrix structure and function and numbers of cancer associated fibroblasts.

PubMed

Krishnamachary, Balaji; Stasinopoulos, Ioannis; Kakkad, Samata; Penet, Marie-France; Jacob, Desmond; Wildes, Flonne; Mironchik, Yelena; Pathak, Arvind P; Solaiyappan, Meiyappan; Bhujwalla, Zaver M

2017-03-14

Cyclooxygenase-2 (COX-2) is a critically important mediator of inflammation that significantly influences tumor angiogenesis, invasion, and metastasis. We investigated the role of COX-2 expressed by triple negative breast cancer cells in altering the structure and function of the extracellular matrix (ECM). COX-2 downregulation effects on ECM structure and function were investigated using magnetic resonance imaging (MRI) and second harmonic generation (SHG) microscopy of tumors derived from triple negative MDA-MB-231 breast cancer cells, and a derived clone stably expressing a short hairpin (shRNA) molecule downregulating COX-2. MRI of albumin-GdDTPA was used to characterize macromolecular fluid transport in vivo and SHG microscopy was used to quantify collagen 1 (Col1) fiber morphology. COX-2 downregulation decreased Col1 fiber density and altered macromolecular fluid transport. Immunohistochemistry identified significantly fewer activated cancer associated fibroblasts (CAFs) in low COX-2 expressing tumors. Metastatic lung nodules established by COX-2 downregulated cells were infrequent, smaller, and contained fewer Col1 fibers.COX-2 overexpression studies were performed with tumors derived from triple negative SUM-149 breast cancer cells lentivirally transduced to overexpress COX-2. SHG microscopy identified significantly higher Col1 fiber density in COX-2 overexpressing tumors with an increase of CAFs. These data expand upon the roles of COX-2 in shaping the structure and function of the ECM in primary and metastatic tumors, and identify the potential role of COX-2 in modifying the number of CAFs in tumors that may have contributed to the altered ECM.

γ-Oryzanol suppresses COX-2 expression by inhibiting reactive oxygen species-mediated Erk1/2 and Egr-1 signaling in LPS-stimulated RAW264.7 macrophages.

PubMed

Shin, Soon Young; Kim, Heon-Woong; Jang, Hwan-Hee; Hwang, Yu-Jin; Choe, Jeong-Sook; Kim, Jung-Bong; Lim, Yoongho; Lee, Young Han

2017-09-16

Cyclooxygenase (COX)-2 produces prostanoids, which contribute to inflammatory responses. Nuclear factor (NF)-κB is a key transcription factor mediating COX-2 expression. γ-Oryzanol is an active component in rice bran oil, which inhibits lipopolysaccharide (LPS)-mediated COX-2 expression by inhibiting NF-κB. However, the inhibition of COX-2 expression by γ-oryzanol independently of NF-κB is poorly understood. We found that LPS upregulated Egr-1 expression at the transcriptional level. Forced expression of Egr-1 trans-activated the Cox-2 promoter independently of NF-κB. In contrast, silencing of Egr-1 abrogated LPS-mediated COX-2 expression. LPS produced reactive oxygen species (ROS), which, in turn, induced Egr-1 expression via the Erk1/2 MAPK pathway. ROS scavenging activity of γ-oryzanol suppressed Egr-1 expression by inhibiting the Erk1/2 MAPK pathway. Our results suggest that γ-oryzanol inhibits LPS-mediated COX-2 expression by suppressing Erk1/2-mediated Egr-1 expression. This study supports that γ-oryzanol may be useful for ameliorating LPS-mediated inflammatory responses. Copyright © 2017 Elsevier Inc. All rights reserved.

USP22 acts as an oncogene by regulating the stability of cyclooxygenase-2 in non-small cell lung cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Haibo; Tian, Yue; Yang, Yang

2015-05-08

The histone ubiquitin hydrolase ubiquitin-specific protease 22 (USP22) is an epigenetic modifier and an oncogene that is upregulated in many types of cancer. In non-small cell lung cancer (NSCLC), aberrant expression of USP22 is a predictor of poor survival, as is high expression of cyclooxygenase-2 (COX-2). Despite its oncogenic role, few substrates of USP22 have been identified and its mechanism of action in cancer remains unclear. Here, we identified COX-2 as a direct substrate of USP22 and showed that its levels are modulated by USP22 mediated deubiquitination. Silencing of USP22 downregulated COX-2, decreased its half-life, and inhibited lung carcinoma cellmore » proliferation by directly interacting with and modulating the stability and activity of COX-2 through the regulation of its ubiquitination status. The findings of the present study suggest a potential mechanism underlying the oncogenic role of USP22 mediated by the modulation of the stability and activity of COX-2. - Highlights: • USP22 interacts with COX-2. • USP22 deubiquitinates and stabilizes COX-2. • USP22 is required for COX-2-mediated upregulation of prostaglandin E2.« less

CD40 engagement on dendritic cells induces cyclooxygenase-2 and EP2 receptor via p38 and ERK MAPKs.

PubMed

Harizi, Hedi; Limem, Ilef; Gualde, Norbert

2011-02-01

We have previously reported that cyclooxygenase (COX)-2-derived prostaglandin (PG)E2 critically regulates dendritic cell (DC) inflammatory phenotype and function through EP2/EP4 receptor subtypes. As genes activated by CD40 engagement are directly relevant to inflammation, we examined the effects of CD40 activation on inflammatory PGs in murine bone marrow-derived DC (mBM-DC). We showed for the first time that activation of mBM-DC with agonist anti-CD40 monoclonal antibody (anti-CD40 mAb) dose dependently induces the synthesis of significant amounts of PGE2 via inducible expression of COX-2 enzyme, as NS-398, a COX-2-selective inhibitor reduces this upregulation. In contrast to lipopolysaccharide, which upregulates mBM-DC surface levels of EP2 and EP4 receptors, CD40 crosslinking on mBM-DC increases EP2, but not EP4, receptor expression. Flow cytometry analysis and radioligand-binding assay showed that EP2 was the major EP receptor subtype, which binds to PGE2 at the surface of anti-CD40-activated mBM-DC. Upregulation of COX-2 and EP2 levels by CD40 engagement was accompanied by dose-dependent phosphorylation of p38 and ERK1/2 mitogen-activated protein kinase (MAPK) and was abrogated by inhibitors of both pathways. Collectively, we demonstrated that CD40 engagement on mBM-DC upregulates COX-2 and EP2 receptor expression through activation of p38 and ERK1/2 MAPK signaling. Triggering the PGE2/EP2 pathway by anti-CD40 mAb resulted on the induction of Th2 immune response. Thus, CD40-induced production of PGE2 by mBM-DC could represent a negative feedback mechanism involving EP2 receptor and limiting the propagation of Th1 responses. Blocking CD40 pathway may represent a novel therapeutic pathway of inhibiting COX-2-derived prostanoids in chronically inflamed tissues (that is, arthritis).

Differential cyclooxygenase-2 expression in squamous cell carcinoma and adenocarcinoma of the uterine cervix.

PubMed

Kim, Yong Bae; Kim, Gwi Eon; Pyo, Hong Ryull; Cho, Nam Hoon; Keum, Ki Chang; Lee, Chang Geol; Seong, Jinsil; Suh, Chang Ok; Park, Tchan Kyu

2004-11-01

To determine the differential expression of cyclooxygenase-2 (COX-2) in patients with squamous cell carcinoma (SCC) and adenocarcinoma (ADC) of the uterine cervix and the prognostic significance of COX-2 expression in these histologic types. A total of 105 International Federation of Gynecology and Obstetrics Stage IIB uterine cervical cancer patients were screened for COX-2 expression immunohistochemically. COX-2 expression was determined in invasive cervical SCC (n = 84) and invasive cervical ADC (n = 21). To determine the clinical significance of COX-2 expression by histologic type, the patients were arbitrarily divided into four groups: SCC/COX-2 negative (n = 64); SCC/COX-2 positive (n = 20); ADC/COX-2 negative (n = 9); and ADC/COX-2 positive (n = 12). The clinical response to treatment, patterns of treatment failure, and survival data by COX-2 expression were compared for these two major histologic types. Univariate and multivariate analyses were performed to identify the prognostic factors influencing survival. Immunohistochemical examination showed that COX-2 expression was more frequently observed in ADC than in SCC (57% vs. 24%, p = 0.007). Moreover, COX-2 expression was an important predictor of treatment response, irrespective of the histologic type. All COX-2-negative patients achieved complete remission after initial treatment; 17% of SCC patients and 33% of ADC patients with COX-2 expression did not have complete remission after the initial treatment. The incidence of local failure for those with COX-2 expression was significantly greater than for COX-2-negative patients, regardless of histologic type. With a minimal follow-up of 60 months, the overall 5-year actuarial survival rate for SCC and ADC patients was 79% and 62%, respectively (p = 0.05). The 5-year disease-free survival rate for SCC and ADC patients was 73% and 56%, respectively (p = 0.13). Irrespective of the pathologic type, COX-2-positive patients had an unfavorable prognosis. The

Cyclooxygenase-2 inhibitors for non-small-cell lung cancer: A phase II trial and literature review.

PubMed

Yokouchi, Hiroshi; Kanazawa, Kenya; Ishida, Takashi; Oizumi, Satoshi; Shinagawa, Naofumi; Sukoh, Noriaki; Harada, Masao; Ogura, Shigeaki; Munakata, Mitsuru; Dosaka-Akita, Hirotoshi; Isobe, Hiroshi; Nishimura, Masaharu

2014-09-01

Several preclinical and clinical studies have demonstrated that cyclooxygenase-2 (COX-2) inhibitors are efficient for the treatment of non-small-cell lung cancer (NSCLC). However, two recent phase III clinical trials using COX-2 inhibitors in combination with platinum-based chemotherapy failed to demonstrate a survival benefit. Thus, validation and discussion regarding the usefulness of COX-2 inhibitors for patients with NSCLC are required. We conducted a prospective trial using COX-2 inhibitors for the treatment of 50 NSCLC patients accrued between April, 2005 and July, 2006. Patients with untreated advanced NSCLC received oral meloxicam (150 mg daily), carboplatin (area under the curve = 5 mg/ml × min on day 1) and docetaxel (60 mg/m 2 on day 1) every 3 weeks. The primary endpoint was response rate. The response and disease control rates were 36.0 and 76.0%, respectively. The time-to-progression (TTP) and overall survival (OS) were 5.7 months [95% confidence interval (CI): 4.6-6.7] and 13.7 months (95% CI: 11.4-15.9), respectively. The 1-year survival ratio was 56.0%. Grade 3 neuropathy was observed in only 1 patient. We performed tumor immunohistochemistry for COX-2 and p27 and investigated the correlation between their expression and clinical outcome. COX-2 expression in the tumor tended to correlate with a higher response rate (50.0% in the high- and 18.2% in the low-COX-2 group; P=0.092). Based on our results and previous reports, various trial designs, such as the prospective use of COX-2 inhibitors only for patients with COX-2-positive NSCLC, including the exploratory analysis of biomarkers associated with the COX-2 pathway, may be worth further consideration.

Rebamipide induces the gastric mucosal protective factor, cyclooxygenase-2, via activation of 5'-AMP-activated protein kinase.

PubMed

Lee, Sunyoung; Jeong, Seongkeun; Kim, Wooseong; Kim, Dohoon; Yang, Yejin; Yoon, Jeong-Hyun; Kim, Byung Joo; Min, Do Sik; Jung, Yunjin

2017-01-29

Rebamipide, an amino acid derivative of 2(1H)-quinolinone, has been used for mucosal protection, healing of gastroduodenal ulcers, and treatment of gastritis. Induction of cyclooxygenase (COX)-2, a gastric mucosal protective factor, by rebamipide has been suggested as the major mechanism of the drug action. However, how rebamipide induces COX-2 at the molecular level needs further investigation. In this study, the molecular mechanism underlying the induction of COX-2 by rebamipide was investigated. In gastric carcinoma cells and macrophage cells, rebamipide induced phosphorylation of AMP-activated protein kinase (AMPK), leading to phosphorylation of acetyl-CoA carboxylase (ACC), a substrate of AMPK. The induction of COX-2 by rebamipide was dependent on AMPK activation because compound C, an AMPK inhibitor, abolished COX-2 induction by rebamipide. In a mouse ulcer model, rebamipide protected against hydrochloric acid/ethanol-induced gastric ulcer, and these protective effects were deterred by co-administration of compound C. In parallel, in the gastric tissues, rebamipide increased the phosphorylation AMPK, whereas compound C reduced the levels of COX-2 and phosphorylated ACC, which were increased by rebamipide. Taken together, the activation of AMPK by rebamipide may be a molecular mechanism that contributes to induction of COX-2, probably resulting in protection against gastric ulcers. Copyright © 2016 Elsevier Inc. All rights reserved.

Hexavalent Chromium Cr(VI) Up-Regulates COX-2 Expression through an NFκB/c-Jun/AP-1–Dependent Pathway

PubMed Central

Zuo, Zhenghong; Cai, Tongjian; Li, Jingxia; Zhang, Dongyun; Yu, Yonghui

2012-01-01

Background: Hexavalent chromium [Cr(VI)] is recognized as a human carcinogen via inhalation. However, the molecular mechanisms by which Cr(VI) causes cancers are not well understood. Objectives: We evaluated cyclooxygenase-2 (COX-2) expression and the signaling pathway leading to this induction due to Cr(VI) exposure in cultured cells. Methods: We used the luciferase reporter assay and Western blotting to determine COX-2 induction by Cr(VI). We used dominant negative mutant, genetic knockout, gene knockdown, and chromatin immunoprecipitation approaches to elucidate the signaling pathway leading to COX-2 induction. Results: We found that Cr(VI) exposure induced COX-2 expression in both normal human bronchial epithelial cells and mouse embryonic fibroblasts in a concentration- and time-dependent manner. Deletion of IKKβ [inhibitor of transcription factor NFκB (IκB) kinase β; an upstream kinase responsible for nuclear factor κB (NFκB) activation] or overexpression of TAM67 (a dominant-negative mutant of c-Jun) dramatically inhibited the COX-2 induction due to Cr(VI), suggesting that both NFκB and c-Jun/AP-1 pathways were required for Cr(VI)-induced COX-2 expression. Our results show that p65 and c-Jun are two major components involved in NFκB and AP-1 activation, respectively. Moreover, our studies suggest crosstalk between NFκB and c-Jun/AP-1 pathways in cellular response to Cr(VI) exposure for COX-2 induction. Conclusion: We demonstrate for the first time that Cr(VI) is able to induce COX-2 expression via an NFκB/c-Jun/AP-1–dependent pathway. Our results provide novel insight into the molecular mechanisms linking Cr(VI) exposure to lung inflammation and carcinogenesis. PMID:22472290

Inflammation in gastric cancer: Interplay of the COX-2/prostaglandin E2 and Toll-like receptor/MyD88 pathways.

PubMed

Echizen, Kanae; Hirose, Osamu; Maeda, Yusuke; Oshima, Masanobu

2016-04-01

Cyclooxygenase-2 (COX-2) and its downstream product prostaglandin E2 (PGE2 ) play a key role in generation of the inflammatory microenvironment in tumor tissues. Gastric cancer is closely associated with Helicobacter pylori infection, which stimulates innate immune responses through Toll-like receptors (TLRs), inducing COX-2/PGE2 pathway through nuclear factor-κB activation. A pathway analysis of human gastric cancer shows that both the COX-2 pathway and Wnt/β-catenin signaling are significantly activated in tubular-type gastric cancer, and basal levels of these pathways are also increased in other types of gastric cancer. Expression of interleukin-11, chemokine (C-X-C motif) ligand 1 (CXCL1), CXCL2, and CXCL5, which play tumor-promoting roles through a variety of mechanisms, is induced in a COX-2/PGE2 pathway-dependent manner in both human and mouse gastric tumors. Moreover, the COX-2/PGE2 pathway plays an important role in the maintenance of stemness with expression of stem cell markers, including CD44, Prom1, and Sox9, which are induced in both gastritis and gastric tumors through a COX-2/PGE2 -dependent mechanism. In contrast, disruption of Myd88 results in suppression of the inflammatory microenvironment in gastric tumors even when the COX-2/PGE2 pathway is activated, indicating that the interplay of the COX-2/PGE2 and TLR/MyD88 pathways is needed for inflammatory response in tumor tissues. Furthermore, TLR2/MyD88 signaling plays a role in maintenance of stemness in normal stem cells as well as gastric tumor cells. Accordingly, these results suggest that targeting the COX-2/PGE2 pathway together with TLR/MyD88 signaling, which would suppress the inflammatory microenvironment and maintenance of stemness, could be an effective preventive or therapeutic strategy for gastric cancer. © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Development of Antioxidant COX-2 Inhibitors as Radioprotective Agents for Radiation Therapy—A Hypothesis-Driven Review

PubMed Central

Laube, Markus; Kniess, Torsten; Pietzsch, Jens

2016-01-01

Radiation therapy (RT) evolved to be a primary treatment modality for cancer patients. Unfortunately, the cure or relief of symptoms is still accompanied by radiation-induced side effects with severe acute and late pathophysiological consequences. Inhibitors of cyclooxygenase-2 (COX-2) are potentially useful in this regard because radioprotection of normal tissue and/or radiosensitizing effects on tumor tissue have been described for several compounds of this structurally diverse class. This review aims to substantiate the hypothesis that antioxidant COX-2 inhibitors are promising radioprotectants because of intercepting radiation-induced oxidative stress and inflammation in normal tissue, especially the vascular system. For this, literature reporting on COX inhibitors exerting radioprotective and/or radiosensitizing action as well as on antioxidant COX inhibitors will be reviewed comprehensively with the aim to find cross-points of both and, by that, stimulate further research in the field of radioprotective agents. PMID:27104573

Cyclooxygenase and lipoxygenase gene expression in the inflammogenesis of breast cancer.

PubMed

Kennedy, Brian M; Harris, Randall E

2018-05-07

We examined the expression of major inflammatory genes, cyclooxygenase-1 and 2 (COX1, COX2) and arachidonate 5-lipoxygenase (ALOX5) in 1090 tumor samples of invasive breast cancer from The Cancer Genome Atlas (TCGA). Mean cyclooxygenase expression (COX1 + COX2) ranked in the upper 99th percentile of all 20,531 genes and surprisingly, the mean expression of COX1 was more than tenfold higher than COX2. Highly significant correlations were observed between COX2 with eight tumor-promoting genes (EGR2, IL6, RGS2, B3GNT5, SGK1, SLC2A3, SFRP1 and ETS2) and between ALOX5 and ten tumor promoter genes (CD33, MYOF1, NLRP1, GAB3, CD4, IFR8, CYTH4, BTK, FGR, CD37). Expression of CYP19A1 (aromatase) was significantly correlated with COX2, but only in tumors positive for ER, PR and HER2. Tumor-promoting genes correlated with the expression of COX1, COX2, and ALOX5 are known to effectively increase mitogenesis, mutagenesis, angiogenesis, cell survival, immunosuppression and metastasis in the pathogenesis of breast cancer.

Toward the understanding of the molecular basis for the inhibition of COX-1 and COX-2 by phenolic compounds present in Uruguayan propolis and grape pomace.

PubMed

Paulino, Margot; Alvareda, Elena; Iribarne, Federico; Miranda, Pablo; Espinosa, Victoria; Aguilera, Sara; Pardo, Helena

2016-12-01

Propolis and grape pomace have significant amounts of phenols which can take part in anti-inflammatory mechanisms. As the cyclooxygenases 1 and 2 (COX-1 and COX-2) are involved in said mechanisms, the possibility for a selective inhibition of COX-2 was analyzed in vitro and in silico. Propolis and grape pomace from Uruguayan species were collected, extracted in hydroalcoholic mixture and analyzed. Based on phenols previously identified, and taking as reference the crystallographic structures of COX-1 and COX-2 in complex with the commercial drug Celecoxib, a molecular docking procedure was devised to adjust 123 phenolic molecular models at the enzyme-binding sites. The most important results of this work are that the extracts have an overall inhibition activity very similar in COX-1 and COX-2, i.e. they do not possess selective inhibition activity for COX-2. Nevertheless, 10 compounds of the phenolic database turned out to be more selective and 94 phenols resulted with similar selectivity than Celecoxib, an outcome that accounts for the overall experimental inhibition measures. Binding site environment observations showed increased polarity in COX-2 as compared with COX-1, suggesting that polarity is the key for selectivity. Accordingly, the screening of molecular contacts pointed to the residues: Arg106, Gln178, Leu338, Ser339, Tyr341, Tyr371, Arg499, Ala502, Val509, and Ser516, which would explain, at the atomic level, the anti-inflammatory effect of the phenolic compounds. Among them, Gln178 and Arg499 appear to be essential for the selective inhibition of COX-2.

Leptin induces CREB-dependent aromatase activation through COX-2 expression in breast cancer cells.

PubMed

Kim, Hyung Gyun; Jin, Sun Woo; Kim, Yong An; Khanal, Tilak; Lee, Gi Ho; Kim, Se Jong; Rhee, Sang Dal; Chung, Young Chul; Hwang, Young Jung; Jeong, Tae Cheon; Jeong, Hye Gwang

2017-08-01

Leptin plays a key role in the control of adipocyte formation, as well as in the associated regulation of energy intake and expenditure. The goal of this study was to determine if leptin-induced aromatase enhances estrogen production and induces tumor cell growth stimulation. To this end, breast cancer cells were incubated with leptin in the absence or presence of inhibitor pretreatment, and changes in aromatase and cyclooxygenase-2 (COX-2) expression were evaluated at the mRNA and protein levels. Transient transfection assays were performed to examine the aromatase and COX-2 gene promoter activities and immunoblot analysis was used to examine protein expression. Leptin induced aromatase expression, estradiol production, and promoter activity in breast cancer cells. Protein levels of phospho-STAT3, PKA, Akt, ERK, and JNK were increased by leptin. Leptin also significantly increased cAMP levels, cAMP response element (CRE) activation, and CREB phosphorylation. In addition, leptin induced COX-2 expression, promoter activity, and increased the production of prostaglandin E 2 . Finally, a COX-2 inhibitor and aromatase inhibitor suppressed leptin-induced cell proliferation in MCF-7 breast cancer cells. Together, our data show that leptin increased aromatase expression in breast cancer cells, which was correlated with COX-2 upregulation, mediated through CRE activation and cooperation among multiple signaling pathways. Copyright © 2017 Elsevier Ltd. All rights reserved.

Constitutively expressed COX-2 in osteoblasts positively regulates Akt signal transduction via suppression of PTEN activity.

PubMed

Li, Ching-Ju; Chang, Je-Ken; Wang, Gwo-Jaw; Ho, Mei-Ling

2011-02-01

Cyclooxygenase-2 (COX-2) is thought to be an inducible enzyme, but increasing reports indicate that COX-2 is constitutively expressed in several organs. The status of COX-2 expression in bone and its physiological role remains undefined. Non-selective non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 inhibitors, which commonly suppress COX-2 activity, were reported to suppress osteoblast proliferation via Akt/FOXO3a/p27(Kip1) signaling, suggesting that COX-2 may be the key factor of the suppressive effects of NSAIDs on proliferation. Although Akt activation correlates with PTEN deficiency and cell viability, the role of COX-2 on PTEN/Akt regulation remains unclear. In this study, we hypothesized that COX-2 may be constitutively expressed in osteoblasts and regulate PTEN/Akt-related proliferation. We examined the localization and co-expression of COX-2 and p-Akt in normal mouse femurs and in cultured mouse (mOBs) and human osteoblasts (hOBs). Our results showed that osteoblasts adjacent to the trabeculae, periosteum and endosteum in mouse femurs constitutively expressed COX-2, while COX-2 co-expressed with p-Akt in osteoblasts sitting adjacent to trabeculae in vivo, and in mOBs and hOBs in vitro. We further used COX-2 siRNA to test the role of COX-2 in Akt signaling in hOBs; COX-2 silencing significantly inhibited PTEN phosphorylation, enhanced PTEN activity, and suppressed p-Akt level and proliferation. However, replenishment of the COX-2 enzymatic product, PGE2, failed to reverse COX-2-dependent Akt phosphorylation. Furthermore, transfection with recombinant human COX-2 (rhCOX-2) significantly reversed COX-2 siRNA-suppressed PTEN phosphorylation, but this effect was reduced when the enzymatic activity of rhCOX-2 was blocked. This finding indicated that the effect of COX-2 on PTEN/Akt signaling is not related to PGE2 but still dependent on COX-2 enzymatic activity. Conversely, COX-1 silencing did not affect PTEN/Akt signaling. Our findings provide

COX-2 Promotes Migration and Invasion by the Side Population of Cancer Stem Cell-Like Hepatocellular Carcinoma Cells

PubMed Central

Guo, Zhe; Jiang, Jing-Hang; Zhang, Jun; Yang, Hao-Jie; Yang, Fu-Quan; Qi, Ya-Peng; Zhong, Yan-Ping; Su, Jie; Yang, Ri-Rong; Li, Le-Qun; Xiang, Bang-De

2015-01-01

Abstract Cancer stem cells (CSCs) are thought to be responsible for tumor relapse and metastasis due to their abilities to self-renew, differentiate, and give rise to new tumors. Cyclooxygenase-2 (COX-2) is highly expressed in several kinds of CSCs, and it helps promote stem cell renewal, proliferation, and radioresistance. Whether and how COX-2 contributes to CSC migration and invasion is unclear. In this study, COX-2 was overexpressed in the CSC-like side population (SP) of the human hepatocellular carcinoma (HCC) cell line HCCLM3. COX-2 overexpression significantly enhanced migration and invasion of SP cells, while reducing expression of metastasis-related proteins PDCD4 and PTEN. Treating SP cells with the selective COX-2 inhibitor celecoxib down-regulated COX-2 and caused a dose-dependent reduction in cell migration and invasion, which was associated with up-regulation of PDCD4 and PTEN. These results suggest that COX-2 exerts pro-metastatic effects on SP cells, and that these effects are mediated at least partly through regulation of PDCD4 and PTEN expression. These results further suggest that celecoxib may be a promising anti-metastatic agent to reduce migration and invasion by hepatic CSCs. PMID:26554780

Thymoquinone suppresses migration of LoVo human colon cancer cells by reducing prostaglandin E2 induced COX-2 activation.

PubMed

Hsu, Hsi-Hsien; Chen, Ming-Cheng; Day, Cecilia Hsuan; Lin, Yueh-Min; Li, Shin-Yi; Tu, Chuan-Chou; Padma, Viswanadha Vijaya; Shih, Hui-Nung; Kuo, Wei-Wen; Huang, Chih-Yang

2017-02-21

To identify potential anti-cancer constituents in natural extracts that inhibit cancer cell growth and migration. Our experiments used high dose thymoquinone (TQ) as an inhibitor to arrest LoVo (a human colon adenocarcinoma cell line) cancer cell growth, which was detected by cell proliferation assay and immunoblotting assay. Low dose TQ did not significantly reduce LoVo cancer cell growth. Cyclooxygenase 2 (COX-2) is an enzyme that is involved in the conversion of arachidonic acid into prostaglandin E2 (PGE2) in humans. PGE2 can promote COX-2 protein expression and tumor cell proliferation and was used as a control. Our results showed that 20 μmol/L TQ significantly reduced human LoVo colon cancer cell proliferation. TQ treatment reduced the levels of p-PI3K, p-Akt, p-GSK3β, and β-catenin and thereby inhibited the downstream COX-2 expression. Results also showed that the reduction in COX-2 expression resulted in a reduction in PGE2 levels and the suppression of EP2 and EP4 activation. Further analysis showed that TG treatment inhibited the nuclear translocation of β-catenin in LoVo cancer cells. The levels of the cofactors LEF-1 and TCF-4 were also decreased in the nucleus following TQ treatment in a dose-dependent manner. Treatment with low dose TQ inhibited the COX-2 expression at the transcriptional level and the regulation of COX-2 expression efficiently reduced LoVo cell migration. The results were further verified in vivo by confirming the effects of TQ and/or PGE2 using tumor xenografts in nude mice. TQ inhibits LoVo cancer cell growth and migration, and this result highlights the therapeutic advantage of using TQ in combination therapy against colorectal cancer.

Vitex negundo inhibits cyclooxygenase-2 inflammatory cytokine-mediated inflammation on carrageenan-induced rat hind paw edema

PubMed Central

Chattopadhyay, Pronobesh; Hazarika, Soilyadhar; Dhiman, Sunil; Upadhyay, Aadesh; Pandey, Anurag; Karmakar, Sanjeev; Singh, Lokendra

2012-01-01

Background: Vitex negundo L. (Verbenaceae) is a hardy plant widely distributed in the Indian subcontinent and used for treatment of a wide spectrum of health disorders in traditional and folk medicine, some of which have been experimentally validated. In present study, we aimed to investigate the anti-inflammatory effects of V. negundo in carrageenan-induced paw edema in rats, and to investigate the probable mechanism of anti-inflammatory action. Materials and Methods: Paw edema was produced by injecting 1% solution of carrageenan, and the paw volume was measured before and after carrageenan injection up to 5 h. V. negundo leaf oil was extracted using a Clevenger apparatus and administered by a trans-dermal route to Wistar rats and the percentage of inhibition of inflammation was observed using a Plethysmometer by comparing a compound aerosol-based formulation with 1 mg diclofinac diethylamine BP and 7 mg methyl salicylate IP/kg body weight served as a standard drug whereas paraffin oil served as the placebo group. After withdrawing of blood, serum was separated and cyclooxygenase (COX)-1 and COX-2 inhibitory activities were measured by the enzyme immuno assay (EIA) method by using a COX inhibitor screening assay kit. Results and Discussion: V. negundo leaf oil significantly (P < 0.05) reduced the carrageenan-induced paw edema as compared to the placebo group (paraffin oil) and 1 mg diclofinac diethylamine BP and 7 mg methyl salicylate IP showed the maximum inhibition of paw edema as compared to the V. negundo leaf oil treated group and the control group. Also in the present study V. negundo leaf oil showed significantly (P < 0.05) inhibits COX-1 pathways rather than COX-2 pathways as compared to the V. negundo leaf oil treated group. Conclusion: It is suggested that the V. negundo leaf oil is a potent anti-inflammatory agent and acts via inhibition of COX-2 without much interfering COX-1 pathways. PMID:22923950

Expression of prostaglandin metabolising enzymes COX-2 and 15-PGDH and VDR in human granulosa cells.

PubMed

Thill, Marc; Becker, Steffi; Fischer, Dorothea; Cordes, Tim; Hornemann, Amadeus; Diedrich, Klaus; Salehin, Darius; Friedrich, Michael

2009-09-01

Prostaglandins (PGs) within the periovulatory follicle are essential for various female reproductive functions such as follicular development and maturation. In animal models, granulosa cells express the PG synthesizing enzyme cyclooxygenase-2 (COX-2) and the PG inactivating enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH). First references suggest a correlation between vitamin D and prostaglandin metabolism through the impact of 1,25(OH)2D3 (calcitriol) on the expression of COX-2 and 15-PGDH. The expression of COX-2, 15-PGDH and the vitamin D receptor (VDR) in human granulosa cells (COV434, hGC and HGL5), which were originally isolated from different stages of follicular maturation, was determined by real-time PCR (RT-PCR) and Western blot analysis. A positive correlation of COX-2 and VDR protein was found in the COV434 and HGL5 cells and an inverse correlation of 15-PGDH and VDR protein levels in all the investigated cell types. There may be a link between VDR, associated target genes and prostaglandin metabolism in human follicular maturation and luteolysis.

Increased dietary sodium induces COX2 expression by activating NFκB in renal medullary interstitial cells.

PubMed

He, Wenjuan; Zhang, Min; Zhao, Min; Davis, Linda S; Blackwell, Timothy S; Yull, Fiona; Breyer, Matthew D; Hao, Chuan-Ming

2014-02-01

High salt diet induces renal medullary cyclooxygenase 2 (COX2) expression. Selective blockade of renal medullary COX2 activity in rats causes salt-sensitive hypertension, suggesting a role for renal medullary COX2 in maintaining systemic sodium balance. The present study characterized the cellular location of COX2 induction in the kidney of mice following high salt diet and examined the role of NFκB in mediating this COX2 induction in response to increased dietary salt. High salt diet (8 % NaCl) for 3 days markedly increased renal medullary COX2 expression in C57Bl/6 J mice. Co-immunofluorescence using a COX2 antibody and antibodies against aquaporin-2, ClC-K, aquaporin-1, and CD31 showed that high salt diet-induced COX2 was selectively expressed in renal medullary interstitial cells. By using NFκB reporter transgenic mice, we observed a sevenfold increase of luciferase activity in the renal medulla of the NFκB-luciferase reporter mice following high salt diet, and a robust induction of enhanced green fluorescent protein (EGFP) expression mainly in renal medullary interstitial cells of the NFκB-EGFP reporter mice following high salt diet. Treating high salt diet-fed C57Bl/6 J mice with selective IκB kinase inhibitor IMD-0354 (8 mg/kg bw) substantially suppressed COX2 induction in renal medulla, and also significantly reduced urinary prostaglandin E2 (PGE2). These data therefore suggest that renal medullary interstitial cell NFκB plays an important role in mediating renal medullary COX2 expression and promoting renal PGE2 synthesis in response to increased dietary sodium.

Formononetin inhibits enterovirus 71 replication by regulating COX- 2/PGE₂ expression.

PubMed

Wang, Huiqiang; Zhang, Dajun; Ge, Miao; Li, Zhuorong; Jiang, Jiandong; Li, Yuhuan

2015-03-01

The activation of ERK, p38 and JNK signal cascade in host cells has been demonstrated to up-regulate of enterovirus 71 (EV71)-induced cyclooxygenase-2 (COX-2)/ prostaglandins E2 (PGE₂) expression which is essential for viral replication. So, we want to know whether a compound can inhibit EV71 infection by suppressing COX-2/PGE₂ expression. The antiviral effect of formononetin was determined by cytopathic effect (CPE) assay and the time course assays. The influence of formononetin for EV71 replication was determined by immunofluorescence assay, western blotting assay and qRT-PCR assay. The mechanism of the antiviral activity of formononetin was determined by western blotting assay and ELISA assay. Formononetin could reduce EV71 RNA and protein synthesis in a dose-dependent manner. The time course assays showed that formononetin displayed significant antiviral activity both before (24 or 12 h) and after (0-6 h) EV71 inoculation in SK-N-SH cells. Formononetin was also able to prevent EV71-induced cytopathic effect (CPE) and suppress the activation of ERK, p38 and JNK signal pathways. Furthermore, formononetin could suppress the EV71-induced COX-2/PGE₂ expression. Also, formononetin exhibited similar antiviral activities against other members of Picornaviridae including coxsackievirus B2 (CVB2), coxsackievirus B3 (CVB3) and coxsackievirus B6 (CVB6). Formononetin could inhibit EV71-induced COX-2 expression and PGE₂ production via MAPKs pathway including ERK, p38 and JNK. Formononetin exhibited antiviral activities against some members of Picornaviridae. These findings suggest that formononetin could be a potential lead or supplement for the development of new anti-EV71 agents in the future.

Study of osteoarthritis treatment with anti-inflammatory drugs: cyclooxygenase-2 inhibitor and steroids.

PubMed

Cho, Hongsik; Walker, Andrew; Williams, Jeb; Hasty, Karen A

2015-01-01

Patients with osteoarthritis (OA), a condition characterized by cartilage degradation, are often treated with steroids, nonsteroidal anti-inflammatory drugs (NSAIDs), and cyclooxygenase-2 (COX-2) selective NSAIDs. Due to their inhibition of the inflammatory cascade, the drugs affect the balance of matrix metalloproteinases (MMPs) and inflammatory cytokines, resulting in preservation of extracellular matrix (ECM). To compare the effects of these treatments on chondrocyte metabolism, TNF-α was incubated with cultured chondrocytes to mimic a proinflammatory environment with increasing production of MMP-1 and prostaglandin E2 (PGE2). The chondrocytes were then treated with either a steroid (prednisone), a nonspecific COX inhibitor NSAID (piroxicam), or a COX-2 selective NSAID (celecoxib). Both prednisone and celecoxib decreased MMP-1 and PGE-2 production while the nonspecific piroxicam decreased only the latter. Both prednisone and celecoxib decreased gene expression of MMP-1 and increased expression of aggrecan. Increased gene expression of type II collagen was also noted with celecoxib. The nonspecific piroxicam did not show these effects. The efficacy of celecoxib in vivo was investigated using a posttraumatic OA (PTOA) mouse model. In vivo, celecoxib increases aggrecan synthesis and suppresses MMP-1. In conclusion, this study demonstrates that celecoxib and steroids exert similar effects on MMP-1 and PGE2 production in vitro and that celecoxib may demonstrate beneficial effects on anabolic metabolism in vivo.

Growth and adherence of Staphylococcus aureus were enhanced through the PGE2 produced by the activated COX-2/PGE2 pathway of infected oral epithelial cells

PubMed Central

Wang, Yuxia; Ren, Biao; Zhou, Xuedong; Liu, Shiyu; Zhou, Yujie; Li, Bolei; Jiang, Yaling; Li, Mingyun; Feng, Mingye

2017-01-01

Staphylococcus aureus is a major pathogen of varieties of oral mucous infection. Prostaglandin E2 (PGE2) is a pro-inflammatory factor and Cyclooxygenase 2 (COX-2) is a critical enzyme of PGE2 biosynthesis. The purpose of this study is to investigate whether Staphylococcus aureus can increase PGE2 production of oral epithelial cells and how PGE2 functions in the growth and adherence of Staphylococcus aureus. mRNA levels of COX-2, fnbpA and fnbpB were estimated by quantitative PCR. PGE2 production was measured by Enzyme Linked Immunosorbent Assay (ELISA). The binding biomass of Staphylococcus aureus to human fibronectin was investigated by crystal violet staining and confocal laser scanning microscopy and the adherent force was measured by atomic force microscope (AFM). The COX-2 mRNA level and PGE2 production were increased by Staphylococcus aureus. PGE2 promoted the growth and biofilm formation of Staphylococcus aureus, enhanced the attachment of Staphylococcus aureus to the human fibronectin as well as to the HOK cells. The transcription of fnbpB was up-regulated by PGE2 in both early and middle exponential phase but not fnbpA. These results suggest that the activation of COX-2/PGE2 pathway in oral epithelial cell by Staphylococcus aureus can in turn facilitate the growth and the ability to adhere of the pathogen. These findings uncover a new function of PGE2 and may lead to the potential of COX-2/PGE2 targeting in the therapy of inflammation and cancer in both which the COX-2/PGE2 pathway were observed activated. PMID:28472126

Growth and adherence of Staphylococcus aureus were enhanced through the PGE2 produced by the activated COX-2/PGE2 pathway of infected oral epithelial cells.

PubMed

Wang, Yuxia; Ren, Biao; Zhou, Xuedong; Liu, Shiyu; Zhou, Yujie; Li, Bolei; Jiang, Yaling; Li, Mingyun; Feng, Mingye; Cheng, Lei

2017-01-01

Staphylococcus aureus is a major pathogen of varieties of oral mucous infection. Prostaglandin E2 (PGE2) is a pro-inflammatory factor and Cyclooxygenase 2 (COX-2) is a critical enzyme of PGE2 biosynthesis. The purpose of this study is to investigate whether Staphylococcus aureus can increase PGE2 production of oral epithelial cells and how PGE2 functions in the growth and adherence of Staphylococcus aureus. mRNA levels of COX-2, fnbpA and fnbpB were estimated by quantitative PCR. PGE2 production was measured by Enzyme Linked Immunosorbent Assay (ELISA). The binding biomass of Staphylococcus aureus to human fibronectin was investigated by crystal violet staining and confocal laser scanning microscopy and the adherent force was measured by atomic force microscope (AFM). The COX-2 mRNA level and PGE2 production were increased by Staphylococcus aureus. PGE2 promoted the growth and biofilm formation of Staphylococcus aureus, enhanced the attachment of Staphylococcus aureus to the human fibronectin as well as to the HOK cells. The transcription of fnbpB was up-regulated by PGE2 in both early and middle exponential phase but not fnbpA. These results suggest that the activation of COX-2/PGE2 pathway in oral epithelial cell by Staphylococcus aureus can in turn facilitate the growth and the ability to adhere of the pathogen. These findings uncover a new function of PGE2 and may lead to the potential of COX-2/PGE2 targeting in the therapy of inflammation and cancer in both which the COX-2/PGE2 pathway were observed activated.

Transcutaneous electrical nerve stimulation attenuates CFA-induced hyperalgesia and inhibits spinal ERK1/2-COX-2 pathway activation in rats

PubMed Central

2013-01-01

Background Transcutaneous electrical nerve stimulation (TENS) is a non-pharmacologic treatment for pain relief. In previous animal studies, TENS effectively alleviated Complete Freund’s Adjuvant (CFA)- or carrageenan-induced inflammatory pain. Although TENS is known to produce analgesia via opioid activation in the brain and at the spinal level, few reports have investigated the signal transduction pathways mediated by TENS. Prior studies have verified the importance of the activation of extracellular signal-regulated kinase (ERK) signal transduction pathway in the spinal cord dorsal horn (SCDH) in acute and persistent inflammatory pains. Here, by using CFA rat model, we tested the efficacy of TENS on inhibiting the expressions of p-ERK1/2 and of its downstream cyclooxygenase-2 (COX-2) and the level of prostaglandin E2 (PGE2) at spinal level. Methods Rats were randomly divided into control, model and TENS groups, and injected subcutaneously with 100 μl CFA or saline in the plantar surface of right hind paw. Rats in the TENS group were treated with TENS (constant aquare wave, 2 Hz and 100 Hz alternating frequencies, intensities ranging from 1 to 2 mA, lasting for 30 min each time) at 5 h and 24 h after injection. Paw withdrawal thresholds (PWTs) were measured with dynamic plantar aesthesiometer at 3d before modeling and 5 h, 6 h, and 25 h after CFA injection. The ipsilateral sides of the lumbar spinal cord dosral horns were harvested for detecting the expressions of p-ERK1/2 and COX-2 by western blot analysis and qPCR, and PGE2 by ELISA. Results CFA-induced periphery inflammation decreased PWTs and increased paw volume of rats. TENS treatment significantly alleviated mechanical hyperalgesia caused by CFA. However, no anti-inflammatory effect of TENS was observed. Expression of p-ERK1/2 protein and COX-2 mRNA was significantly up-regualted at 5 h and 6 h after CFA injection, while COX-2 and PGE2 protein level only increased at 6 h after modeling

Triptolide inhibits COX-2 expression by regulating mRNA stability in TNF-{alpha}-treated A549 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Lixin; Zhang, Shuang; Jiang, Zhenzhou

2011-12-09

Highlights: Black-Right-Pointing-Pointer Triptolide inhibited COX-2 expression and the half-life of COX-2 mRNA is decreased. Black-Right-Pointing-Pointer The HuR protein shuttling from nucleus to cytoplasm is inhibited by triptolide. Black-Right-Pointing-Pointer Triptolide inhibited 3 Prime -UTR fluorescence reporter gene activity. Black-Right-Pointing-Pointer COX-2 mRNA binding to HuR is decreased by triptolide in pull-down experiments. -- Abstract: Cyclooxygenase-2 (COX-2) over-expression is frequently associated with human non-small-cell lung cancer (NSCLC) and involved in tumor proliferation, invasion, angiogenesis and resistance to apoptosis. In the present study, the effects of triptolide on COX-2 expression in A549 cells were investigated and triptolide was found to inhibit TNF-{alpha}-induced COX-2 expression.more » In our further studies, it was found that triptolide decreased the half-life of COX-2 mRNA dramatically and that it inhibited 3 Prime -untranslated region (3 Prime -UTR) fluorescence reporter gene activity. Meanwhile, triptolide inhibited the HuR shuttling from nucleus to cytoplasm. After triptolide treatment, decreased COX-2 mRNA in pull-down experiments with anti-HuR antibodies was observed, indicating that the decreased cytoplasmic HuR is responsible for the decreased COX-2 mRNA. Taken together, our results provided evidence for the first time that triptolide inhibited COX-2 expression by COX-2 mRNA stability modulation and post-transcriptional regulation. These results provide a novel mechanism of action for triptolide which may be important in the treatment of lung cancer.« less

Carrageenan-induced mouse paw oedema is biphasic, age-weight dependent and displays differential nitric oxide cyclooxygenase-2 expression

PubMed Central

Posadas, Inmaculada; Bucci, Mariarosaria; Roviezzo, Fiorentina; Rossi, Antonietta; Parente, Luca; Sautebin, Lidia; Cirino, Giuseppe

2004-01-01

Injection of carrageenan 1% (50 μl) in the mouse paw causes a biphasic response: an early inflammatory response that lasts 6 h and a second late response that peaks at 72 h, declining at 96 h. Only mice 7- or 8-week old, weighing 32–34 g, displayed a consistent response in both phases. In 8-week-old mice, myeloperoxidase (MPO) levels are significantly elevated in the early phase at 6 h and reach their maximum at 24 h to decline to basal value at 48 h. Nitrate+nitrite (NOx) levels in the paw are maximal after 2 h and slowly decline thereafter in contrast to prostaglandin E2 levels that peak in the second phase at the 72 h point. Western blot analysis showed that inducible nitric oxide synthase (iNOS) is detectable at 6 h and cyclooxygenase 2 (COX-2) at 24 h point, respectively. Analysis of endothelial nitric oxide synthase (eNOS), iNOS and COX-2 expression at 6 and 24 h in 3–8-week-old mice demonstrated that both eNOS and iNOS expressions are dependent upon the age–weight of mice, as opposite to COX-2 that is present only in the second phase of the oedema and is not linked to mouse age–weight. Subplantar injection of carrageenan to C57BL/6J causes a biphasic oedema that is significantly reduced by about 20% when compared to CD1 mice. Interestingly, in these mice, iNOS expression is absent up to 6 h, as opposite to CD1, and becomes detectable at the 24 h point. Cyclooxygenase (COX-1) expression is upregulated between 4 and 24 h after carrageenan injection, whereas in CD1 mice COX-1 remains unchanged after irritant agent injection. MPO levels are maximal at the 24 h point and they are significantly lower, at 6 h point, than MPO levels detected in CD1 mice. In conclusion, mouse paw oedema is biphasic and age-weight dependent. The present results are the first report on the differential expressions of eNOS, iNOS, COX-1 and COX-2 in response to carrageenan injection in the two phases of the mouse paw oedema. PMID:15155540

Osthole ameliorates neurogenic and inflammatory hyperalgesia by modulation of iNOS, COX-2, and inflammatory cytokines in mice.

PubMed

Singh, Gurjit; Bhatti, Rajbir; Mannan, Rahul; Singh, Drishtant; Kesavan, Anup; Singh, Palwinder

2018-05-07

Osthole is a bioactive component reported in medicinal plants such as Angelica pubescens and Cnidium monnieri, known for analgesic activity. However, the toxicity, median effective dose (ED 50 ), and dual modulation of nitric oxide and cyclooxygenase pathways along with inflammatory cytokines of osthole are yet to be determined. The animals (mice) were assessed for general behaviour and mortality in varying doses (50, 300, and 2000 mg kg -1 ) of osthole for acute toxicity over 14 days. The analgesic activity was investigated using acetic acid and formalin-induced hyperalgesia, and anti-inflammatory activity was explored in carrageenan-induced paw oedema. ED 50 of osthole was calculated using Design Expert software. Involvement of nitric oxide and cyclooxygenase pathways was investigated by agonist challenges with L-arginine and substance P, respectively. The expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was determined in spinal sections by immunohistochemical analysis. Lipopolysaccharide (LPS) challenge was used to assess in vivo effect on inflammatory cytokines (TNFα and IL-6). Acute toxicity studies revealed no behavioural abnormality or mortality on osthole treatment and unremarkable histological findings. Osthole was found to significantly decrease acetic acid and formalin-induced hyperalgesia (ED 50  = 5.43 mg kg -1 ) and carrageenan-induced paw oedema with no toxicity symptoms. Osthole produced a marked decrease in iNOS and COX-2 expression as well as TNFα and IL-6. The findings corroborate to modulation of iNOS and COX-2 and inflammatory cytokines by osthole. This study provides promising insights and prospects for application of osthole in pain management.

Synthesis, biological evaluation and docking analysis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones as potential cyclooxygenase-2 (COX-2) inhibitors.

PubMed

Grover, Jagdeep; Kumar, Vivek; Sobhia, M Elizabeth; Jachak, Sanjay M

2014-10-01

As a part of our continued efforts to discover new COX inhibitors, a series of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones were synthesized and evaluated for in vitro COX inhibitory potential. Within this series, seven compounds (3a-d, 3h, 3k and 3q) were identified as potential and selective COX-2 inhibitors (COX-2 IC50's in 1.79-4.35μM range; COX-2 selectivity index (SI)=6.8-16.7 range). Compound 3b emerged as most potent (COX-2 IC50=1.79μM; COX-1 IC50 >30μM) and selective COX-2 inhibitor (SI >16.7). Further, compound 3b displayed superior anti-inflammatory activity (59.86% inhibition of edema at 5h) in comparison to celecoxib (51.44% inhibition of edema at 5h) in carrageenan-induced rat paw edema assay. Structure-activity relationship studies suggested that N-phenyl ring substituted with p-CF3 substituent (3b, 3k and 3q) leads to more selective inhibition of COX-2. To corroborate obtained experimental biological data, molecular docking study was carried out which revealed that compound 3b showed stronger binding interaction with COX-2 as compared to COX-1. Copyright © 2014 Elsevier Ltd. All rights reserved.

Clinical pharmacology of lumiracoxib: a selective cyclo-oxygenase-2 inhibitor.

PubMed

Rordorf, Christiane M; Choi, Les; Marshall, Paul; Mangold, James B

2005-01-01

Lumiracoxib (Prexige) is a selective cyclo-oxygenase (COX)-2 inhibitor developed for the treatment of osteoarthritis, rheumatoid arthritis and acute pain. Lumiracoxib possesses a carboxylic acid group that makes it weakly acidic (acid dissociation constant [pKa] 4.7), distinguishing it from other selective COX-2 inhibitors. Lumiracoxib has good oral bioavailability (74%). It is rapidly absorbed, reaching maximum plasma concentrations 2 hours after dosing, and is highly plasma protein bound. Lumiracoxib has a short elimination half-life from plasma (mean 4 hours) and demonstrates dose-proportional plasma pharmacokinetics with no accumulation during multiple dosing. In patients with rheumatoid arthritis, peak lumiracoxib synovial fluid concentrations occur 3-4 hours later than in plasma and exceed plasma concentrations from 5 hours after dosing to the end of the 24-hour dosing interval. These data suggest that lumiracoxib may be associated with reduced systemic exposure, while still reaching sites where COX-2 inhibition is required for pain relief. Lumiracoxib is metabolised extensively prior to excretion, with only a small amount excreted unchanged in urine or faeces. Lumiracoxib and its metabolites are excreted via renal and faecal routes in approximately equal amounts. The major metabolic pathways identified involve oxidation of the 5-methyl group of lumiracoxib and/or hydroxylation of its dihaloaromatic ring. Major metabolites of lumiracoxib in plasma are the 5-carboxy, 4'-hydroxy and 4'-hydroxy-5-carboxy derivatives, of which only the 4'-hydroxy derivative is active and COX-2 selective. In vitro, the major oxidative pathways are catalysed primarily by cytochrome P450 (CYP) 2C9 with very minor contribution from CYP1A2 and CYP2C19. However, in patients genotyped as poor CYP2C9 metabolisers, exposure to lumiracoxib (area under the plasma concentration-time curve) is not significantly increased compared with control subjects, indicating no requirement for adjustment

XRCC5 cooperates with p300 to promote cyclooxygenase-2 expression and tumor growth in colon cancers

PubMed Central

Hao, Jiajiao; Chen, Miao; Yu, Wendan; Guo, Wei; Chen, Yiming; Huang, Wenlin; Deng, Wuguo

2017-01-01

Cyclooxygenase (COX) is the rate-limiting enzyme in prostaglandins (PGs) biosynthesis. Previous studies indicate that COX-2, one of the isoforms of COX, is highly expressed in colon cancers and plays a key role in colon cancer carcinogenesis. Thus, searching for novel transcription factors regulating COX-2 expression will facilitate drug development for colon cancer. In this study, we identified XRCC5 as a binding protein of the COX-2 gene promoter in colon cancer cells with streptavidin-agarose pulldown assay and mass spectrometry analysis, and found that XRCC5 promoted colon cancer growth through modulation of COX-2 signaling. Knockdown of XRCC5 by siRNAs inhibited the growth of colon cancer cells in vitro and of tumor xenografts in a mouse model in vivo by suppressing COX-2 promoter activity and COX-2 protein expression. Conversely, overexpression of XRCC5 promoted the growth of colon cancer cells by activating COX-2 promoter and increasing COX-2 protein expression. Moreover, the role of p300 (a transcription co-activator) in acetylating XRCC5 to co-regulate COX-2 expression was also evaluated. Immunofluorescence assay and confocal microscopy showed that XRCC5 and p300 proteins were co-located in the nucleus of colon cancer cells. Co-immunoprecipitation assay also proved the interaction between XRCC5 and p300 in nuclear proteins of colon cancer cells. Cell viability assay indicated that the overexpression of wild-type p300, but not its histone acetyltransferase (HAT) domain deletion mutant, increased XRCC5 acetylation, thereby up-regulated COX-2 expression and promoted the growth of colon cancer cells. In contrast, suppression of p300 by a p300 HAT-specific inhibitor (C646) inhibited colon cancer cell growth by suppressing COX-2 expression. Taken together, our results demonstrated that XRCC5 promoted colon cancer growth by cooperating with p300 to regulate COX-2 expression, and suggested that the XRCC5/p300/COX-2 signaling pathway was a potential target in the

Vitamin D Inhibits COX-2 Expression and Inflammatory Response by Targeting Thioesterase Superfamily Member 4*

PubMed Central

Wang, Qingsong; He, Yuhu; Shen, Yujun; Zhang, Qianqian; Chen, Di; Zuo, Caojian; Qin, Jing; Wang, Hui; Wang, Junwen; Yu, Ying

2014-01-01

Inadequate vitamin D status has been linked to increased risk of type 2 diabetes and cardiovascular disease. Inducible cyclooxygenase (COX) isoform COX-2 has been involved in the pathogenesis of such chronic inflammatory diseases. We found that the active form of vitamin D, 1,25(OH)2D produces dose-dependent inhibition of COX-2 expression in murine macrophages under both basal and LPS-stimulated conditions and suppresses proinflammatory mediators induced by LPS. Administration of 1,25(OH)2D significantly alleviated local inflammation in a carrageenan-induced paw edema mouse model. Strikingly, the phosphorylation of both Akt and its downstream target IκBα in macrophages were markedly suppressed by 1,25(OH)2D in the presence and absence of LPS stimulation through up-regulation of THEM4 (thioesterase superfamily member 4), an Akt modulator protein. Knockdown of both vitamin D receptor and THEM4 attenuated the inhibitory effect of 1,25(OH)2D on COX-2 expression in macrophages. A functional vitamin D-responsive element in the THEM4 promoter was identified by chromatin immunoprecipitation and luciferase reporter assay. Our results indicate that vitamin D restrains macrophage-mediated inflammatory processes by suppressing the Akt/NF-κB/COX-2 pathway, suggesting that vitamin D supplementation might be utilized for adjunctive therapy for inflammatory disease. PMID:24619416

Celecoxib exerts protective effects in the vascular endothelium via COX-2-independent activation of AMPK-CREB-Nrf2 signalling.

PubMed

Al-Rashed, Fahad; Calay, Damien; Lang, Marie; Thornton, Clare C; Bauer, Andrea; Kiprianos, Allan; Haskard, Dorian O; Seneviratne, Anusha; Boyle, Joseph J; Schönthal, Alex H; Wheeler-Jones, Caroline P; Mason, Justin C

2018-04-19

Although concern remains about the athero-thrombotic risk posed by cyclo-oxygenase (COX)-2-selective inhibitors, recent data implicates rofecoxib, while celecoxib appears equivalent to NSAIDs naproxen and ibuprofen. We investigated the hypothesis that celecoxib activates AMP kinase (AMPK) signalling to enhance vascular endothelial protection. In human arterial and venous endothelial cells (EC), and in contrast to ibuprofen and naproxen, celecoxib induced the protective protein heme oxygenase-1 (HO-1). Celecoxib derivative 2,5-dimethyl-celecoxib (DMC) which lacks COX-2 inhibition also upregulated HO-1, implicating a COX-2-independent mechanism. Celecoxib activated AMPKα (Thr172) and CREB-1 (Ser133) phosphorylation leading to Nrf2 nuclear translocation. Importantly, these responses were not reproduced by ibuprofen or naproxen, while AMPKα silencing abrogated celecoxib-mediated CREB and Nrf2 activation. Moreover, celecoxib induced H-ferritin via the same pathway, and increased HO-1 and H-ferritin in the aortic endothelium of mice fed celecoxib (1000 ppm) or control chow. Functionally, celecoxib inhibited TNF-α-induced NF-κB p65 (Ser536) phosphorylation by activating AMPK. This attenuated VCAM-1 upregulation via induction of HO-1, a response reproduced by DMC but not ibuprofen or naproxen. Similarly, celecoxib prevented IL-1β-mediated induction of IL-6. Celecoxib enhances vascular protection via AMPK-CREB-Nrf2 signalling, a mechanism which may mitigate cardiovascular risk in patients prescribed celecoxib. Understanding NSAID heterogeneity and COX-2-independent signalling will ultimately lead to safer anti-inflammatory drugs.