A lipid-derived endogenous inducer of COX-2: a bridge between inflammation and oxidative stress

Several lines of evidence indicate that the oxidative modification of protein and the subsequent accumulation of the modified proteins have been found in cells during aging, oxidative stress, and in various pathological states including premature diseases, muscular dystrophy, rheumatoid arthritis, and atherosclerosis. The important agents that give rise to the modification of a protein may be represented by reactive aldehydic intermediates, such as ketoaldehydes, 2-alkenals and 4-hydroxy-2-alkenals. These reactive aldehydes are considered important mediators of cell damage due to their ability to covalently modify biomolecules, which can disrupt important cellular functions and can cause mutations. Furthermore, the adduction of aldehydes to apolipoprotein B in low-density lipoproteins (LDL) has been strongly implicated in the mechanism by which LDL is converted to an atherogenic form that is taken up by macrophages, leading to the formation of foam cells. During the search for an endogenous inducer of cyclooxygenase-2 (COX-2), an inducible isoform responsible for high levels of prostaglandin production during inflammation and immune responses, 4-hydroxy-2-noennal (HNE), one of the most representative lipid peroxidation product, has been identified as the potential inducer of COX-2. In addition, the following study on the molecular mechanism of the COX-2 induction by HNE has unequivocally established that a serum component, which is eventually identified to be denatured LDL, is essential for COX-2 induction. Here I review current understanding of the mechanisms by which HNE in cooperation with the serum component activates gene expression of COX-2.

Effects of San-Huang-Xie-Xin-Tang on U46619-induced increase in pulmonary arterial blood pressure

ETHNOPHARMACOLOGICAL RELEVANCE

San-Huang-Xie-Xin-Tang (SHXT), composed of Coptidis rhizoma, Scutellariae radix and Rhei rhizoma, is traditionally used to treat hypertension.

AIM OF THE STUDY

Our aim was to investigate the pharmacology effect of SHXT on a thromboxane A(2) analogue U46619-induced increase in pulmonary hypertension and protein expression in primary pulmonary smooth muscle cells (PASMCs).

MATERIALS AND METHODS

Arterial blood pressure and isometric tension in the aorta and pulmonary artery of rats were measured by pressure and force transducers, respectively. Protein expressions on PASMCs were detected by Western blotting.

RESULTS

SHXT significantly attenuated U46619-induced increase in arterial blood pressure. The inhibitory effect of SHXT on pulmonary arterial pressure was greater than systemic arterial pressure in U46619 treated rats. Similarly, the inhibitory effect of SHXT on U46619-induced vasoconstriction in rat pulmonary arterial rings was greater than that in aortic rings. In U46619 treated PASMCs, SHXT down-regulated expression of phosphodiesterase type 5 (PDE5), Rho-kinase (ROCK) II, cyclooxygenase-2 (COX-2) and up-regulated expression of soluble guanylyl cyclase (sGC) alpha(1) and sGCbeta(1).

CONCLUSIONS

SHXT attenuated U46619-induced increase in systemic and pulmonary arterial blood pressure. Inhibition of PDE5, ROCK-II, COX-2 and stimulation of sGC may play important roles in the cardiovascular effects of SHXT.

Differences in expression of tumor markers between pre- and postmenopausal women with invasive cervical cancer

THE AIM of the present study was to investigate the differences in the expression of tumor markers in squamous cell and in adenomatous carcinomas in pre- and postmenopausal women, respectively.

PATIENTS AND METHODS

The study population comprised 53 premenopausal and 107 postmenopausal women. Thirty-four tumors were adenomatous (n=31) or adenosquamous carcinomas (n=3), distributed between 13 premenopausal and 21 postmenopausal women. The remaining 126 squamous cell carcinomas were diagnosed in 40 pre- and 86 postmenopausal women. Expression of ten tumor markers of possible clinical importance in cervical cancer was evaluated.

RESULTS

Expression of three tumor markers, p53 (>0% vs. 0%), p27 (> or =20% vs. <20%) and cyclooxygenase-2 (COX-2) (high intensity vs. moderate/none) differed significantly between pre- compared to postmenopausal women with squamous cell (p27; 54% vs. 72%, p=0.009) or adenomatous carcinomas (p53; 8% vs. 63%, p=0.006 and COX-2; 46% vs. 20%, p=0.03). All results were adjusted for clinical cancer stage.

CONCLUSION

The unusual age-specific incidence curve in cervical cancer has rarely been related to expression of tumor markers. Age-related differences in expression of tumor markers could reflect some age-related different biological mechanisms in cervical cancer.

The effect of polysaccharide extracted from the marine alga Capsosiphon fulvescens on ethanol administration

Seaweed extracts have recently been found to have antioxidant and antitumor activities. Capsosiphon fulvescens (Cf) is a green alga and nutrient-dense food source. In a previous study, we extracted polysaccharide from Cf (Cf-PS) and demonstrated its antitumor effect in gastric cancer cells. In this report, we describe the protective effect of Cf-PS against alcohol-induced gastric injury in rats and adenocarcinoma (AGS) cells. In vivo assay revealed stomach damage in rats treated with alcohol alone; however, the stomach condition of rats co-treated with Cf-PS and alcohol matched that of the control group. Cf-PS also inhibited alcohol-induced cell death in AGS cells. Compared with alcohol treatment alone, Cf-PS and alcohol co-treatment increased phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt but inhibited poly-ADP-ribose polymerase (PARP) cleavage. Thus, ERK1/2 and Akt activation are instrumental in the protective effect of Cf-PS against alcohol-induced cell death in AGS cells. Moreover, Cf-PS treatment reduced the expressions of cyclooxygenase-2 (COX-2) and the inducible form of nitric oxide (iNOS), proteins related to ulcers. These results suggest that Cf-PS could help protect against alcohol-induced peptic ulcers.

Ameliorative prospective of alpha-mangostin, a xanthone derivative from Garcinia mangostana against beta-adrenergic cathecolamine-induced myocardial toxicity and anomalous cardiac TNF-alpha and COX-2 expressions in rats

Altered membrane integrity and inflammation play a key role in cardiovascular damage. We investigated the salubrious effect of exogenously administered alpha-mangostin against beta-adrenergic cathecolamine-induced cardiovascular toxicity with special reference to membrane ATPases, lysosomal hydrolases and inflammatory mediators TNF-alpha and Cyclooxygenase-2 (COX-2) expressions in albino rats. Induction of rats with isoproterenol (150mg/kg body wt, i.p.) for 2 days resulted in a significant increase in the activities of serum and cardiac lysosomal hydrolases (beta-d-glucuronidase, beta-d-galactosidase, beta-d-N-acetylglucosaminidase, acid phosphatase and cathepsin-D). A significant increase in cardiac levels of sodium, calcium with a decrease in the level of potassium paralleled by abnormal activities of membrane-bound phosphatases (Na(+)-K(+) ATPase, Ca(2+) ATPase and Mg(2+) ATPase) were observed in the heart of ISO-administered rats. Cardiac TNF-alpha and COX-2 expressions were assessed by Western blotting. Cardiac TNF-alpha and COX-2 expressions were significantly elevated in ISO-intoxicated rats. Pre-co-treatment with alpha-mangostin (200mg/kg body wt.) orally for 8 days significantly attenuated these abnormalities and restored the levels to near normalcy when compared to ISO intoxicated group of rats. In conclusion, alpha-mangostin preserves the myocardial membrane integrity and extenuates anomalous TNF-alpha and COX-2 expressions by mitigating ISO-induced oxidative stress and cellular damage effectively. Restoration of cellular normalcy accredits the cytoprotective role of alpha-mangostin.

[Effect of NS-398 on cyclooxygenase-2 expression and proliferation of HepG2 cells]

OBJECTIVE

To investigate anticancer effect and molecular mechanism of N-[(Cyclohexyloxy)-4-nitrophenyl] methanesulfonamide on HepG2 cells in vitro.

METHODS

HepG2 cells were treated with various concentrations (100, 200, 300, 400 micromol/L) of NS-398 [selective for cyclooxygenase 2 (COX-2) inhibition]. Cell growth was measured by MTT method, DNA fragmentation gel analysis was used to analyze the apoptosis cells, DNA ploidy and apoptotic cell percentage were examined by flow cytometry (FCM). PGE2 concentration was measured by radioimmunoassay method. The expressions of COX-2 were also examined by Western blot analysis.

RESULTS

NS-398 inhibited HepG2 cell proliferation and induced apoptosis in a concentration-dependent manner. DNA ploidy analysis showed that S phase cells were significantly decreased and quiescent G1 phase was accumulated with NS-398 concentration increasing. The IC50 of 24 hours was 300 micromol/L. The release of PGE2 was significantly reduced in HepG2 cells with the values of NS-398 being (0.70 +/- 0.02), (0.48 +/- 0.02), (0.29 +/- 0.01) and (0.18 +/- 0.01) respectively, as compared with control group (0.03 +/- 0.01). NS-398 could inhibit the activity and expression of COX-2, with higher concentration, it can significantly down-regulate the expression of COX-2 (t = 3.736, 1.623, 1.810, 2.587, P < 0.01).

CONCLUSION

NS-398 might significantly inhibit the proliferation of HepG2 cells and induce apoptosis. The mechanisms were related with the accumulation of quiescent G1 phase and the inhibition of COX-2 activity.

Immunohistochemical increase in cyclooxygenase-2 without apoptosis in different brain areas of subchronic nicotine- and D-amphetamine-treated rats

Cyclooxygenase-2 (COX-2) upregulation has been related to both neurodegeneration and physiological processes. To clarify whether nicotine-induced upregulation of COX-2 occurs, and to analyse its significance, a comparative immunohistochemical and Western blot study was performed on the frontoparietal cortex, hippocampus and cerebellar cortex of rats treated (14 days) with nicotine, D(+)amphetamine (0.35 and 1.16 mg free base/kg/day, respectively), or both drugs simultaneously. None of these treatments promoted neuronal apoptosis. Lipid peroxidation increased in the hippocampus of the nicotine-treated rats and in all the brain regions examined in the D(+)amphetamine rats, but not in the double-treated animals. Both molecules increased the COX-2 content (as determined by the number of immunopositive neurons and the intensity of their immunodeposits) in an area-, layer- and neuron type-dependent manner, in all brain regions in which a large number of COX-2 immunopositive neurons were observed in controls (the somatosensory cortical areas, CA-1, CA-3, the gyrus dentatus, the ectorhinal/perirhinal areas, and the gyrus cingularis). No increase was seen in the motor cortical areas, while a reduction was recorded in the cerebellar cortex; these regions had only a few immunopositive neurons in controls. Western blot analysis revealed a 50-80% increase in COX-2 in the brain cortex and hippocampus of nicotine-treated rats, and similar increases (150-200%) in the cortex of the D(+)amphetamine- and nicotine + D(+)amphetamine-treated rats. Nicotine-induced upregulation of COX-2 seems to be related to neuronal plasticity rather than neurodegeneration. Nicotine agonists might be useful in the treatment of cognitive disorders.

Correlation between expression of cyclooxygenase-2 and the presence of CD4+ infiltrating T-lymphocyte in human primary hepatocellular carcinoma

BACKGROUND/AIMS

Recent studies have found that Cyclooxygenase-2(Cox-2) is frequently inappropriately expressed in primary hepatocellular carcinoma (HCC), suggesting that abnormal Cox-2 expression plays an important role in hepatocarcinogenesis. But it remains controversial in these reports. Moreover, there are only a few studies on the correlation between Cox-2 and infiltrating immunocytes in the tumor-microenvironment. CD4+ tumor-infiltrating lymphocytes (TIL) and infiltrating immunocytes around the tumor are closely correlated to the development of the tumor, but so far no reports are available showing the relationship among Cox-2, CD4+ TIL of tumor and CD4+ infiltrating T-lymphocytes of adjoining non-tumorous (ANT) tissues in tumor-microenvironment. This study is designed to appropriately select and collect patients' specimens to better reflect Cox-2 expression in human HCC, and also to stress the correlation among Cox-2, CD4+ TIL and CD4+ infiltrating T-lymphocytes in the tumor-microenvironment.

METHODOLOGY

Tumor tissue, and its matched ANT tissue removed less than 1 cm from the solid tumor border, were obtained from 25 HCC patients all of whom came from Hunan province, China, and were infected with hepatitis B virus (HBV). Normal liver tissues of 10 hemangiomas were collected as controls. Both Cox-2 expression and the number of CD4+ TIL and CD4+ infiltrating T-lymphocyte were detected by immunohistochemistry, and data were analyzed closely with patients' clinical figures so as to investigate the correlation between the 3 elements.

RESULTS

In 25 HCC patients, remarkably higher Cox-2 expression in both tumor and ANT tissues was observed compared with normal liver tissues (p < 0.001). The percentage of Cox-2 positive cells was, remarkably, higher in ANT tissues than in tumors (p < 0.001). Similarly the distribution of CD4+ T cells was significantly higher in ANT tissue than in tumor tissue (p < 0.0001), and also significantly higher in tumor tissue than in normal tissue (p < 0.0001). Importantly, in the group of patients with Cox-2-expressing tumors, the number of CD4+ infiltrating T-lymphocyte in ANT tissues was 79.4(+)9.92/hpf, which is obviously lower (p = 0.019) than that of the group with non-Cox-2-expressing tumors with the number of CD4+ infiltrating T-lymphocyte in ANT tissues at 118.13(+)12.47/hpf. Cox-2 expression of tumors showed a significant negative correlation with number of CD4+ infiltrating T cells of ANT tissues (r = 0.499, p = 0.024). The number of CD4+ TILs are lower in Cox-2-expressing tumors than in non-Cox-2-expressing tumors, but there was not statistical significance (p = 0.057).

CONCLUSIONS

Taken together we suggest in the tumor-microenvironment of HCC the expression of Cox-2 may inhibit the number CD4+ infiltrating T-lymphocyte in ANT tissues. As a result, Cox-2 overexpression may contribute to both suppression of local immune responses and enhancement of metastatic potential in human HCC.

Gastric adenomas: relationship between clinicopathological findings, Helicobacter pylori infection, APC mutations and COX-2 expression

Gastric adenomas are rare neoplastic growths characterized by localized polypoid proliferations of dysplastic epithelium that tend to progress to infiltrating adenocarcinoma. Therefore, the identification of molecular markers that could reliably recognize adenomas at risk of progression is advocated in the clinical management. In this study we investigated, in a series of gastric adenoma specimens from an area at high risk of gastric cancer, the relationship between clinicopathological characteristics of adenoma and Helicobacter pylori infection, APC mutational status, and COX-2 and the down-stream enzyme mPGES1 expression. Helicobacter pylori infection, detected in 24%, and 33% by histology and PCR analyses, respectively, did not show any relationship with growth pattern, localization, size, dysplasia grade and presence of synchronous cancer. Pathogenetic mutations of MCR region (codons 1269-1589) of the APC gene were detected only in one case corresponding to a single, small size, low grade, H. pylori-negative adenoma. The expression of COX-2 largely matched that of mPGES(1). Both were overexpressed in 79% of cases showing a relationship with high-grade dysplasia, size >10 mm and presence of a synchronous carcinoma. In conclusion, COX-2 may play a key role in the development and progression of gastric adenoma and could be an attractive target in the management of gastric adenoma at major risk of cancer development.

Thrombocytes respond to lipopolysaccharide through Toll-like receptor-4, and MAP kinase and NF-κB pathways leading to expression of interleukin-6 and cyclooxygenase-2 with production of prostaglandin E2

Chicken thrombocytes are equivalent in hemostatic function to mammalian platelets. Platelets are enucleated components of mammalian blood, while thrombocytes are nucleated blood leukocytes of chickens. Platelets and thrombocytes share characteristics that contribute to innate immunity. Experiments were conducted to determine if thrombocytes could respond in vitro to lipopolysaccharide (LPS) of Salmonella minnesota through Toll-like receptor-4 (TLR4). The aim was to activate the signal pathways leading to expression of interleukin-6 (IL-6) and inducible cyclooxygenase (COX-2) and to production of prostaglandin E2 (PGE2). Chicken thrombocytes were found to express TLR4, and LPS-induced an increase in thrombocyte mRNA expression of IL-6 and COX-2 with release of PGE2 into culture media. An increase of COX-2 and PGE2 due to LPS stimulation was inhibited by MEK1 inhibitor PD98059, but IL-6 expression was unaffected by PD98059. The IKK-2 inhibitor BMS345541 inhibited IL-6 and COX-2 with reduction of PGE2 concentrations. Therefore, the MAP kinase (MAPK) pathway activates expression of COX-2 and ultimately PGE2 production, but this pathway has little or no influence on IL-6 expression in thrombocytes. The NF-kappaB pathway also influences COX-2 expression and PGE2 production, and it is a primary activation signaling cascade for IL-6 gene expression in chicken thrombocytes. Thrombocytes represent a major component of the innate immune system of chickens in response to LPS and possibly other microbial products.

Expression of the ELAV-like protein HuR in human prostate carcinoma is an indicator of disease relapse and linked to COX-2 expression

The human ELAV-like protein HuR is involved in the stabilization of the mRNAs of a group of genes implicated in the regulation of cellular growth, angiogenesis and rapid inflammatory response. HuR is a nuclear shuttling protein, translocating bound mRNAs from the nucleus to the cytoplasm. We have previously observed an increased expression of cyclooxygenase-2 (COX-2) in prostate cancer while cell culture studies have shown that HuR stabilizes the mRNA of COX-2. Based on these mechanistic data, we aimed to investigate the role of HuR in prostate cancer by a tissue-based analysis combined with functional evaluation using a cell culture approach. Investigating 104 primary prostate carcinomas by immunohistochemistry, we found HuR expression to be shifted from a nuclear staining in normal prostate glands to a cytoplasmic staining in carcinoma tissue (p<0.0001). Cytoplasmic HuR expression was significantly correlated with COX-2 expression (p=0.005). Loss of nuclear HuR expression was an indicator of earlier PSA-relapse both in univariate (p=0.04) and multivariate survival analysis (p=0.04). HuR inhibition by Leptomycin B reduced the inducibility of COX-2 in PC-3 prostate cancer cells. We found that the subcellular localization of HuR is deregulated in a subset of prostate carcinomas, and that this deregulation is linked to an altered expression of the tumorigenic COX-2 protein as well as to an adverse patient prognosis. Our results point to a potential prognostic role of HuR expression in prostate cancer diagnostics and propose HuR as a future therapeutic target in prostate cancer therapy.

Influence of COX-2-induced PGE2 on the initiation and progression of tail regeneration in Northern House Gecko, Hemidactylus flaviviridis

We investigated the role of prostaglandin E2 in reptilian regeneration. Prostaglandin E2 is known to play a vital role during wound healing and cell proliferation. A significant delay in the rate of growth of regenerate after autotomy was observed when the production of prostaglandin E2 was blocked by usage of specific cyclooxygenase inhibitors as compared to control animals and this delay continued to all the defined stages of regeneration. Therefore, prostaglandin E2 could be one of the essential requirements for a successful process of regeneration.

[Intraprostatic urinary reflux associated prostatitis caused by partial urethral obstruction in the rat model]

OBJECTIVE

To investigate the pathogenesis of chronic prostatitis / chronic pelvic pain syndrome (CP / CPPS) by constructing the rat model of intraprostatic urinary reflux associated prostatitis caused by partial urethral obstruction.

METHODS

Fifty-four SD male rats were divided into an experiment group (n = 30) and a partial urethral obstruction (PUO) sham operation group (n = 24). Shinsuke Takechi's surgical method was adopted to achieve PUO and induce intraprostatic urinary reflux in the experiment group. While in the sham operation control group, the prostates were harvested at 1, 3 and 7 days after release from 3-day PUO, their morphological changes observed with the light microscope and the expression of cyclooxygenase-2 (COX-2) examined by immunohistochemistry.

RESULTS

Inflammation was observed in the prostate of the experiment group at 1, 3 and 7 days after release from PUO and alleviated with the passing of time, while the control group remained normal. The expression of COX-2 in the prostate was significantly higher in the experiment group than in the control (P < 0.05) and the staining of COX-2 became stronger with the lapse of time (P < 0.05).

CONCLUSION

An animal model of intraprostatic urinary reflux associated prostatitis was constructed. The up-regulated expression of COX-2 induced by intraprostatic urinary reflux may be closely related with the development of CP / CPPS.

Protective effect of pine (Pinus morrisonicola Hay.) needle on LDL oxidation and its anti-inflammatory action by modulation of iNOS and COX-2 expression in LPS-stimulated RAW 264.7 macrophages

The protective effects of pine (Pinus morrisonicola Hay.) needle on low-density lipoprotein (LDL) oxidation and nitric oxide production in macrophages as well as its bioactive compounds were investigated. Of the four solvent extracts, the ethyl acetate extract of pine needle (EAE-PN) exhibited the strongest scavenging action on free radicals. EAE-PN significantly inhibited copper-induced LDL oxidation through prolonging the lag phase of conjugated dienes formation and decreasing the relative electrophoretic mobility of LDL. Lipid accumulation and foam cell formation were significantly reduced when EAE-PN (75 microg/mL) was added to the medium co-incubated with macrophages cells and copper-induced LDL. EAE-PN also markedly inhibited reactive oxygen species production in RAW 264.7 cells stimulated with lipopolysaccharide (LPS). As regards NO production in cells, EAE-PN showed dose-dependent inhibitory effect on nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells. The inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) protein expressions in LPS-stimulated RAW 264.7 cells were inhibited by EAE-PN. RT-PCR analysis indicated that the iNOS and COX-2 mRNA expression were suppressed by EAE-PN. The major phenolic compounds in EAE-PN were epicatechin and p-coumaric acid by HPLC analysis. The presence of epicatechin and p-coumaric acid in EAE-PN may be partially responsible for the biological action of EAE-PN. Taken together, these results suggest that EAE-PN may provide potential protective effects against LDL oxidation and attenuating excessive NO generation at inflammatory sites; consequently, this may contribute to anti-atherosclerotic and anti-inflammatory effects of EAE-PN.

Hepatocyte growth factor induces anoikis resistance by up-regulation of cyclooxygenase-2 expression in uterine endometrial cancer cells

Cyclooxygenase-2 (COX-2) has been implicated in the promotion of carcinogenesis. Although the role of COX-2 in endometrial cancer remains unclear, recent experiments suggest that COX-2 antagonizes cell apoptosis, increases the invasiveness of malignant cells, and promotes angiogenesis. Hepatocyte growth factor (HGF) is a mesenchymal-derived cytokine and the interaction between HGF and its tyrosine kinase receptor, c-Met proto-oncogene, is associated with tumor progression and metastasis. To investigate the molecular mechanism of HGF-induced anoikis resistance, we analyzed the signal transduction and COX-2 expression in endometrial cancer cells. Here, we show i) the expression of COX-2 protein significantly increased in a dose-dependent manner after HGF stimulation in endometrial cancer cell lines (HEC-IB and RL95-2), reaching 200-270% stimulation at the highest doses of HGF tested (40 ng/ml); ii) flow cytometry and TUNEL analyses revealed that HGF significantly inhibited anoikis of RL95-2 cells; iii) phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002), but not mitogen-activated protein kinase/ERK kinase (MEK) inhibitor (PD98059), specifically blocked HGF-mediated anoikis resistance in RL95-2 cells; and iv) COX-2 inhibitor, Meloxicam, abrogated HGF-mediated anoikis resistance. Our data suggest that HGF induces anoikis resistance in endometrial cancer cells possibly through PI3K/Akt pathway-dependent up-regulation of COX-2 expression.

Transcriptional regulation of the COX-2 expression by nitric oxide in colon cancer cell lines

To determine the effect of nitric oxide (NO) on the cyclooxygenase-2 (COX-2) regulation in colon cancer cell lines we used the physiological NO donor GSNO. The proximal 6.6 kb of the COX-2 promoter was cloned into the pGL3 basic vector and the sequential deletion of the 6.6 kb COX-2 promoter generated promoter constructs of 4, 2.6, 1.9 and 0.9 kb. These constructs clearly show that the main regulatory region lies within 0.9 kb of the transcription start site. Therefore, constructs of the main transcription binding sites within this region namely CRE, NF-IL6 and NF-kappaB and mutations of these sites were used to monitor the transcriptional activation of COX-2. This study was performed on the colon cancer cell lines HCA7 and HCT116 which have a differential expression of COX-2. There was no evidence that the luciferase activity is negatively affected by NO as was previously reported. The CRE and NF-IL6 binding sites within this region were responsible for the constitutive and physiological NO-induced COX-2 transcriptional activity in the HCA7 and HCT116 cells. While NF-kappaB involvement was only observed in the HCT116 cells, the cell lines displayed increased NF-kappaB transcriptional activity after exposure to NO.

Selective cyclooxygenase-2 inhibition suppresses basic fibroblast growth factor expression in human esophageal adenocarcinoma

Inhibition of cyclooxygenase (COX)-2 is reported to suppress growth and induce apoptosis in human esophageal adenocarcinoma (EADC) cells, although the precise biologic mechanism is unclear. In this study we tested the hypothesis that the antitumor activity of COX-2 inhibitors may involve modulation of basic fibroblast growth factor (FGF-2), which is overexpressed in EADC. We evaluated the effects of NS-398, a selective COX-2 inhibitor, on FGF-2 expression and proliferation of EADC cell lines that express COX-2 and those that do not. We also correlated COX-2 and FGF-2 expression with clinico-pathologic findings and outcome in a well-characterized series of surgically resected EADC tissues. Seg-1 cells robustly expressed COX-2 and FGF-2, whereas Bic-1 cells expressed neither transcript. FGF-2 was reduced to undetectable levels in Seg-1 cells following NS-398 treatment, but increased within 4 h of drug removal. NS-398 significantly inhibited the growth of Seg-1 cells, and this effect was ameliorated by addition of exogenous FGF-2. In contrast, NS-398 had no effect on Bic-1 cell proliferation and FGF-2 alone had no effect on proliferation of either cell line. NS-398, or a neutralizing anti-FGF-2 antibody, induced apoptosis in Seg-1 cells, and these effects were inhibited by addition of exogenous FGF-2. COX-2 protein was strongly expressed in 46% (10/22) of EADCs, and was associated with a trend towards reduced disease-free survival. These findings indicate that the antitumor effects of COX-2 inhibition in EADC cells may be mediated via suppression of FGF-2, and that COX-2 may be a clinically relevant molecular marker in the management of human EADC.

Exisulind in combination with celecoxib modulates epidermal growth factor receptor, cyclooxygenase-2, and cyclin D1 against prostate carcinogenesis: in vivo evidence

PURPOSE

Nonsteroidal anti-inflammatory drugs mediate anticancer effects by modulating cyclooxygenase-2 (COX-2)-dependent and/or COX-2-independent mechanism(s); however, the toxicity issue is a concern with single agents at higher doses. In this study, we determined the combined effect of celecoxib, a COX-2 inhibitor, along with exisulind (sulindac sulfone/Aptosyn) at low doses in prostate cancer.

EXPERIMENTAL DESIGN

We used a sequential regimen of N-methyl-N-nitrosourea + testosterone to induce prostate cancer in Wistar-Unilever rats. Following carcinogen treatment, celecoxib and exisulind individually and their combination at low doses were given in NIH-07 diet for 52 weeks. We determined the incidence of prostatic intraepithelial neoplasia, adenocarcinomas, rate of tumor cell proliferation, and apoptosis. Immunohistochemical and Western blot analysis were done to determine COX-2, epidermal growth factor receptor (EGFR), Akt, androgen receptor, and cyclin D1 expression. Serum prostaglandin E2 and tumor necrosis factor-alpha levels were determined using enzyme immunoassay/ELISA assays.

RESULTS

The rats that received celecoxib in combination with exisulind at low doses showed a significant decrease in prostatic intraepithelial neoplasia and adenocarcinomas as well as an enhanced rate of apoptosis. An overall decrease in COX-2, EGFR, Akt, androgen receptor, and cyclin D1 expression was found associated with tumor growth inhibition. Reduced serum levels of COX-2 protein, prostaglandin E2, and tumor necrosis factor-alpha indicated anti-inflammatory effects. A strong inhibition of total and phosphorylated form of EGFR (Tyr(992) and Tyr(845)) and Akt (Ser(473)) was significant in rats given with these agents in combination.

CONCLUSIONS

In this study, we show for the first time that the combination of celecoxib with exisulind at low doses could prevent prostate carcinogenesis by altering key molecular events.

MD-2 controls bacterial lipopolysaccharide hyporesponsiveness in human intestinal epithelial cells

Intestinal epithelial cells (IEC) have adapted to the presence of commensal bacteria through a state of tolerance that involves a limited response to lipopolysaccharide (LPS). Low or absent expression of two LPS receptor molecules, the myeloid differentiation (MD)-2 receptor, and toll-like receptor (TLR)4 was suggested to underlie LPS tolerance in IEC. In the present study we performed transfections of TLR4 and MD-2 alone or combined in different IEC lines derived from intestinal cancer (Caco-2, HT-29, and SW837). We found that LPS responsiveness increased more than 100-fold when IEC were transfected with MD-2 alone, but not TLR4. The release of interleukin (IL)-8, but also the expression of cyclooxygenase (Cox-)2 and the related secretion of prostaglandin (PG)E2 were coordinately stimulated by LPS in IEC transfected with MD-2 alone. Supernatants collected from MD-2-transfected IEC supported LPS activation of naïve HT-29, providing additional support to the concept that MD-2 alone endows IEC with LPS responsiveness. LPS responsiveness detected at concentrations as low as 110 pg/ml, and maximal values obtained by 10 ng/ml were clearly beyond those evoked by classical stimuli as IL-1beta. In polarized cells, apical LPS stimulation was markedly more efficient than basolateral. Our data contradict previous opinion that both TLR4 and MD-2 limit IEC response to LPS, and emphasize the prominent role of MD-2 in intestinal immune responses to Gram-negative bacteria.

Effect of altering dietary omega-6/omega-3 fatty acid ratios on prostate cancer membrane composition, cyclooxygenase-2, and prostaglandin E2

PURPOSE

To determine whether altering the dietary content of omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids affects the growth of androgen-sensitive prostate cancer xenografts, tumor membrane fatty acid composition, and tumor cyclooxygenase-2 and prostaglandin E(2) (PGE(2)) levels.

EXPERIMENTAL DESIGN

Individually caged male severe combined immunodeficiency mice were fed isocaloric 20% kcal fat diets with the fat derived either primarily from n-6 fatty acids (n-6 group) or with the fat consisting of n-6 and n-3 fatty acids in a ratio of 1:1 (n-3 group), and injected s.c. with Los Angeles Prostate Cancer 4 (LAPC-4) cells. Tumor volumes and mouse weights were measured weekly, caloric intake was measured 3 days per week, and tumors and serum were harvested at 8 weeks postinjection.

RESULTS

Tumor growth rates, final tumor volumes, and serum prostate-specific antigen levels were reduced in the n-3 group relative to the n-6 group. The n-3 group tumors had decreased proliferation (Ki67 staining) and increased apoptosis (terminal nucleotidyl transferase-mediated nick end labeling staining). In vitro proliferation of LAPC-4 cells in medium containing n-3 group serum was reduced by 22% relative to LAPC-4 cells cultured in medium containing serum from the n-6 group. The n-6/n-3 fatty acid ratios in serum and tumor membranes were lower in the n-3 group relative to the n-6 group. In addition, n-3 group tumors had decreased cyclooxygenase-2 protein and mRNA levels, an 83% reduction in PGE(2) levels, and decreased vascular endothelial growth factor expression.

CONCLUSION

These results provide a sound basis for clinical trials evaluating the effect of dietary n-3 fatty acids from fish oil on tumor PGE(2) and membrane fatty acid composition, and serum and tumor biomarkers of progression in men with prostate cancer.

TGF-beta1 reduces the heterogeneity of astrocytic cyclooxygenase-2 and nitric oxide synthase-2 gene expression in a stimulus-independent manner

Transforming growth factor-beta1 (TGF-beta1) is upregulated by inflammatory mediators in several neurological diseases/disorders where it either participates in the pathology or provides protection. Often, the biological outcome of TGF-beta1 is dependent upon changes in gene expression. Recently, we demonstrated that TGF-beta1 enhances astrocytic nitric oxide production induced by lipopolysaccharide (LPS) plus interferon-gamma (IFNgamma) by increasing the number of astrocytes in a population that express NOS-2. The purpose of this study was twofold: (1) to determine whether this effect occurs more generally by assessing the effect of TGF-beta1 on another pro-inflammatory gene, cyclooxygenase-2 (COX-2); and (2) to assess stimulus specificity. We found that TGF-beta1 augmented LPS plus IFNgamma-induced COX-2 mRNA and protein expression, by nearly tripling the number of astrocytes that express COX-2. The effect was not stimulus-specific as TGF-beta1 enhanced the number of astrocytes that expressed both COX-2 and NOS-2 protein when either IL-1beta or TNFalpha was used in lieu of LPS. Collectively, these results suggest that TGF-beta1 augments overall protein expression levels of select pro-inflammatory genes in astrocytes in a promiscuous manner by reducing the magnitude of noise in the cellular population.

Clinical significance of prostaglandin E synthase expression in gastric cancer tissue

Studies have linked microsomal prostaglandin E synthase (mPGES)-1 with gastric cancer. The purpose of this study was to determine mPGES-1, mPGES-2, and cytosolic PGES (cPGES) expression in gastric cancer and to evaluate the correlation between mPGES-1 and mPGES-2 expression and clinicopathological factors and cyclooxygenase-2 expression. PGES protein expression was examined by Western blot in gastric cancer cell lines and in biopsy samples from patients with gastric cancer. mPGES-1, mPGES-2, and cPGES protein localizations were examined immunohistochemically in 129 archival gastric cancer surgical resections. mPGES-1 protein expression was found in gastric cancer biopsies and cancer cell lines with differentiated or undifferentiated adenocarcinoma. There was no mPGES-1 expression in nonneoplastic biopsies. All cell lines and tissue samples expressed mPGES-2 and cPGES. Immunohistochemical analysis showed cancer cells expressed mPGES-1 in 47% of cases. mPGES-2 immunoreactivity was seen both in nonneoplastic glandular epithelium and cancer cells; however, cancer cell immunoreactivity was significantly more pronounced in 29% of cases. cPGES expression was constitutive both in nonneoplastic and neoplastic tissues, with no significant variation among cases. mPGES-1 and mPGES-2 expression correlated with cyclooxygenase-2 expression. mPGES-1 and mPGES-2 expression, and tumor-node-metastasis stage had independent prognostic significance under multivariate analysis in patients with gastric cancer overall and in patients with differentiated cancers. However, only tumor-node-metastasis stage and mPGES-2 expression retained independent prognostic significance in patients with poorly differentiated cancers. mPGES-1 and mPGES-2 correlate with clinicopathological factors and may be valuable prognostic factors in gastric cancer.

Developmental regulation of calcineurin isoforms in the rodent kidney: association with COX-2

Calcineurin (Cn)-Aα-deficient mice develop abnormalities of postnatal kidney development, similar to that of cyclooxygenase (COX)-2-deficient mice. The present study was undertaken to examine expression and regulation of Cn isoforms in the developing kidney during the postnatal period and further characterize the relationship between Cn and COX-2. The protein expressions of all three Cn isoforms, including Cn-Aα, -Aβ, and -B, as determined by immunoblotting, increased in parallel in the first postnatal week and declined gradually with age. Renal Cn-Aα and -Aβ mRNA expressions were both developmentally regulated in the same fashion as their protein expressions, whereas renal Cn-B1 mRNA was not obviously induced in the first postnatal week. Immunohistochemistry demonstrated colocalization of Cn-Aα, Cn-Aβ, and COX-2 in the same cells of thick ascending limb and macula densa. Administration with cyclosporine A (2.5 mg·kg−1·day−1) during the postnatal period remarkably suppressed renal COX-2 expression as assessed by both immunoblotting and immunohistochemistry. Deletion of Cn-Aα but not Cn-Aβ in mice significantly reduced renal COX-2 expression at the postnatal period. Together, these data suggest that renal Cn isoforms are subject to normal developmental regulation and they may play a role in postnatal kidney development via interaction with COX-2.

Targeting NOX, INOS and COX-2 in inflammatory cells: chemoprevention using food phytochemicals

Biological, biochemical and physical stimuli activate inflammatory leukocytes, such as macrophages, resulting in induction and synthesis of proinflammatory proteins and enzymes, together with free radicals, as innate immune responses. On the other hand, chronic and dysregulated activation of some inducible enzymes, including NADPH oxidase (NOX), inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, have been shown to play pivotal roles in the development of certain inflammatory diseases such as oncogenesis. While the use of synthetic agents, especially those targeting molecules, is an attractive and reasonable approach to prevent carcinogenesis, it should be noted that traditional herbs and spices also exist along with their active constituents, which have been demonstrated to disrupt inflammatory signal transduction pathways. In this mini-review, the molecular mechanisms of activation or induction of NOX, iNOS and COX-2, as well as some food phytochemicals with marked potential to regulate those key inflammatory molecules, are highlighted. For example, 1'-acetoxychavicol acetate, which occurs in the rhizomes of the subtropical Zingiberaceae plant, has been shown to attenuate NOX-derived superoxide generation in macrophages, as well as lipopolysaccharide-induced nitric oxide and prostaglandin E(2) production through the suppression of iNOS and COX-2 synthesis, respectively. Notably, this phytochemical has exhibited a wide range of cancer prevention activities in several rodent models of inflammation-associated carcinogenesis. Herein, the cancer preventive potentials of several food phytochemicals targeting the induction of NOX, iNOS and COX-2 are described.

The effects of combining docetaxel and cyclooxygenase-2 inhibitors on proliferation and apoptosis in epithelial ovarian cancer

In-vitro studies have shown that taxanes can upregulate cellular cyclooxygenase-2 expression. The purpose of this study is to evaluate the effects of the combination, cyclooxygenase-2 inhibitor and docetaxel, on epithelial ovarian cancer cells. Four epithelial ovarian cancer cell lines (MDAH-2774, SKOV3, OVCAR and CaOV-3) were treated with the specific cyclooxygenase-2 inhibitor NS398 (10 or 100 mumol/l) and docetaxel (0.1, 1 or 10 mumol/l) in various combinations. Apoptosis in the ovarian cancer cells was assessed using TUNEL assay. Multiplex reverse transcription-PCR was used to determine mRNA levels of cyclooxygenase-2, bcl-2 and bax. Treatment of all epithelial ovarian cancer cells with docetaxel resulted in significant apoptotic death. Concurrent treatment of MDAH-2774, SKOV3 and OVCAR cells with docetaxel and NS398 resulted in the reduction of the taxane-induced apoptosis. Similar reduction was seen when the cells were exposed to NS398 for 4 h before docetaxel treatment. Conversely, treating the MDAH-2774 and SKOV3 cells with docetaxel followed by NS398 resulted in a significant increase in apoptosis compared with treatment with the taxane alone. bax mRNA levels were significantly reduced in SKOV3 cells treated concurrently with NS398 and docetaxel; bcl-2 mRNA levels showed no change. When combining docetaxel and a cyclooxygenase-2 inhibitor in the treatment of ovarian cancer cells, the sequencing of the drugs seems to have an important influence on the overall outcome. Using the cyclooxygenase-2 inhibitor before or concurrently with the taxane will result in a reduction of cellular apoptotic death. This might be due to a reduction in the expression of the proapototic gene bax.

Deletion of the AU-rich RNA binding protein Apobec-1 reduces intestinal tumor burden in Apc(min) mice

The RNA-specific cytidine deaminase apobec-1 is an AU-rich RNA binding protein that binds the 3' untranslated region (UTR) of cyclooxygenase-2 (Cox-2) mRNA and stabilizes its turnover in vitro. Cox-2 overexpression accompanies intestinal adenoma formation in both humans and mice. Evidence from both genetic deletion studies as well as from pharmacologic inhibition has implicated Cox-2 in the development of intestinal adenomas in experimental animals and in adenomas and colorectal cancer in humans. Here, we show that small intestinal adenoma formation is dramatically reduced in compound Apc(min/+) apobec-1(-/-) mice when compared with the parental Apc(min/+) strain. This reduced tumor burden was found in association with increased small intestinal apoptosis and reduced proliferation in small intestinal crypt-villus units from compound Apc(min/+) apobec-1(-/-) mice. Intestinal adenomas from compound Apc(min/+) apobec-1(-/-) mice showed a <2-fold increase in Cox-2 mRNA abundance and reduced prostaglandin E(2) content compared with adenomas from the parental Apc(min/+) strain. In addition, there was reduced expression in adenomas from compound Apc(min/+) apobec-1(-/-) mice of other mRNAs (including epidermal growth factor receptor, peroxisome proliferator-activated receptor delta, prostaglandin receptor EP4, and c-myc), each containing the apobec-1 consensus binding site within their 3'-UTR. Adenovirus-mediated apobec-1 introduction into HCA-7 (colorectal cancer) cells showed a dose-dependent increase in Cox-2 protein and stabilization of endogenous Cox-2 mRNA. These findings suggest that deletion of apobec-1, by modulating expression of AU-rich RNA targets, provides an important mechanism for attenuating a dominant genetic restriction point in intestinal adenoma formation.

Expansion of human T regulatory type 1 cells in the microenvironment of cyclooxygenase 2 overexpressing head and neck squamous cell carcinoma

Cyclooxygenase 2 (COX-2) overexpression and production of prostaglandin E(2) (PGE(2)) by head and neck squamous cell carcinomas (HNSCC) induce type 1 regulatory T (Tr1) cells and contribute to carcinogenesis by creating a tolerogenic milieu. To test this hypothesis, CD4(+)CD25(-) T cells obtained from the peripheral blood of 10 normal donors were cocultured with autologous dendritic cells, irradiated HNSCC cells and cytokines, interleukin 2 (IL-2), IL-10, and IL-15. HNSCC cells were either COX-2 negative, constitutively expressed COX-2, were transfected with COX-2, or had COX-2 expression knocked down by small interfering RNA. Other modifications included coculture plus or minus the COX-inhibitor, Diclofenac, or synthetic PGE(2) in the absence of HNSCC. Lymphocytes proliferating in 10-day cocultures were phenotyped by flow cytometry, studied for cytokine production by ELISA and for suppressor function in CFSE inhibition assays plus or minus anti-IL-10 or anti-transforming growth factor-beta(1) (TGF-beta(1)) monoclonal antibodies (mAb). COX-2(+) HNSCC or exogenous PGE(2) induced outgrowth of Tr1 cells with the CD3(+)CD4(+)CD25(-)IL2Rbeta(+)IL2Rgamma(+)FoxP3(+)CTLA-4(+)IL-10(+)TGF-beta(1)(+)IL-4(-) phenotype and high suppressor functions (range, 46-68%). Small interfering RNA knockout of COX-2 gene in HNSCC led to outgrowth of lymphocytes with decreased IL2Rgamma (P = 0.0001), FoxP3 (P = 0.05), and IL-10 (P = 0.035) expression and low suppressor activity (range, 26-34%). Whereas COX-2(+) cocultures contained IL-10 and TGF-beta(1) (medians, 615 and 824 pg/mL), cytokine levels were decreased (P < 0.0001) in COX-2(-) cocultures. Inhibition of COX-2 enzymatic activity in HNSCC abrogated outgrowth of Tr1 cells. Neutralizing mAbs to IL-10 and/or TGF-beta(1) abolished Tr1-mediated suppression. COX-2 overexpression in HNSCC plays a major role in the induction of Tr1 cells in the tumor microenvironment.

COX-2 mRNA expression decreases in the subplantar muscle of rat paw subjected to carrageenan-induced inflammation after low level laser therapy

OBJECTIVE AND DESIGN

Low level laser therapy (LLLT) has been presented as a novel therapy to treat inflammation. Herein we studied the effect of LLLT on the COX-2 mRNA expression in subplantar tissue taken from rats treated with carrageenan.

MATERIAL

The groups consisted of 32 rats: A(1) (Saline), A(2) (Carrageenan), A(3) (Carrageenan + laser 660 nm) and A(4) (Carrageenan + laser 684 nm).

TREATMENT

A(3) and A(4) were irradiated in the first hour after carrageenan.

METHODS

The edema was measured by a plethysmometer and COX-2 mRNA was by RT-PCR. Statistical were evaluated by ANOVA and Tukey-Kramer Test.

RESULTS

Carrageenan increased both edema (A 1)= 0.6 +/- 0.04 vs. A(2)= 2.24 +/- 0.08) and COX-2 mRNA (A(1)= 1.1 +/- 0.26 vs. A(2)= 3.52 +/- 0.69). Irradiation reduced the edema (A(3)= 0.84 +/- 0.09; A(4)= 1.31 +/- 0.05) and the COX-2 mRNA (A(3)= 2.16 +/- 0.28; A(4)= 1.86 +/- 0.20).

CONCLUSION

LLLT reduce the expression of COX-2 mRNA.

[Protective effect of epigallocatechin-3-gallate on inflammatory bowel disease: experiment with rat models of induced colitis]

OBJECTIVE

To explore the protective effect of epigallocatechin-3-gallate (EGCG) on ulcerative colitis (UC) and mechanism thereof.

METHODS

Sixty SD rats underwent enema of trinitrobenzene sulfonic acid (TNBS) to cause UC and then randomly divided into 6 groups: model group, undergoing enema of normal saline (NS) once a day for 2 weeks; positive drug control group, undergoing enema of 5-aminosalicylic acid (ASA), an anti-UC drug; high-dose EGCG group, undergoing enema of 100 mg/kg EGCG; low-dose EGCG group, undergoing 5 enema of 50 mg/kg EGCG; and EGCG pretreatment group, undergoing enema of 100 mg/kg once a day 3 days before the model establishment and then once a day for 2 weeks after the model establishment. Another 12 rats were used as normal controls. Two weeks later the rats were killed. The histological score of the colonic mucosa was evaluated. The cyclooxygenase-2 protein expression in the colonic mucosa was detected by immunohistochemistry and the cyclooxygenase-2 mRNA expression was assessed by semiquantitative reverse-transcription polymerase chain reaction.

RESULTS

The histological score of the model group was 6.4 +/- 2.7, significantly higher than that of the normal control group (1.0 +/- 0.7, P < 0.01). The histological scores of the 5-ASA, and 100 mg/kg and 50 mg/kg EGCG groups were 3.4 +/- 1.8, 2.6 +/- 1.5, and 4.0 +/- 2.0 respectively, all significantly lower than that of the model group (all P < 0.05). The histological scores of the EGCG pretreatment group was the lowest (1.2 +/- 0.8), especially compared with the model group (P < 0.01). Cyclooxygenase -2 mRNA was not expressed in the normal control group, was highly expressed in the model group, and the expression levels of the 5-ASA and EGCG groups were all significantly lower than that of the model group (chi(2) = 22.017, P < 0.05).

CONCLUSION

Preventing and ameliorating colitis by inhibiting cyclooxygenase-2 activity, EGCG may be a potential medicine in treating inflammatory bowel disease.

Discoidin domain receptor 1 receptor tyrosine kinase induces cyclooxygenase-2 and promotes chemoresistance through nuclear factor-kappaB pathway activation

Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase activated by various types of collagens and is known to play a role in cell attachment, migration, survival, and proliferation. However, little is known about the molecular mechanism(s) underlying the role of DDR1 in cancer. We report here that DDR1 induces cyclooxygenase-2 (Cox-2) expression resulting in enhanced chemoresistance. Depletion of DDR1-mediated Cox-2 induction using short hairpin RNA (shRNA) results in increased chemosensitivity. We also show that DDR1 activates the nuclear factor-kappaB (NF-kappaB) pathway and blocking this activation by an I kappaB superrepressor mutant results in the ablation of DDR1-induced Cox-2, leading to enhanced chemosensitivity, indicating that DDR1-mediated Cox-2 induction is NF-kappaB dependent. We identify the upstream activating kinases of the NF-kappaB pathway, IKK beta and IKK gamma, as essential for DDR1-mediated NF-kappaB activation, whereas IKK alpha seems to be dispensable. Finally, shRNA-mediated inhibition of DDR1 expression significantly enhanced chemosensitivity to genotoxic drugs in breast cancer cells. Thus, DDR1 signaling provides a novel target for therapeutic intervention with the prosurvival/antiapoptotic machinery of tumor cells.

Adenovirus type 5 exerts multiple effects on the expression and activity of cytosolic phospholipase A2, cyclooxygenase-2, and prostaglandin synthesis

In this study, we examine how infection of murine and human fibroblasts by adenovirus (Ad) serotype 5 (Ad5) affects the expression and activity of cytosolic phospholipase A2 (cPLA2), cyclooxygenase-2 (COX-2), and production of PGs. Our experiments showed that infection with Ad5 is accompanied by the rapid activation of cPLA2 and the cPLA2-dependent release of [3H]arachidonic acid ([3H]AA). Increased expression of COX-2 was also observed after Ad infection, as was production of PGE2 and PGI2. Later, however, as the infection progressed, release of [3H]AA and production of PGs stopped. Late-stage Ad5-infected cells also did not release [3H]AA or PGs following treatment with a panel of biologically diverse agents. Experiments with UV-inactivated virus confirmed that Ad infection is accompanied by the activation of a host-dependent response that is later inhibited by the virus. Investigations of the mechanism of suppression of the PG pathway by Ad5 did not reveal major effects on the expression or activity of cPLA2 or COX-2. We did note a change in the intracellular position of cPLA2 and found that cPLA2 did not translocate normally in infected cells, raising the possibility that Ad5 interferes with the PG pathway by interfering with the intracellular movement of cPLA2. Taken together, these data reveal dynamic interactions between Ad5 and the lipid mediator pathways of the host and highlight a novel mechanism by which Ad5 evades the host immune response. In addition, our results offer insight into the inflammatory response induced by many Ad vectors lacking early region gene products.

Physiological concentrations of butyrate favorably modulate genes of oxidative and metabolic stress in primary human colon cells

Butyrate, a metabolite of gut flora-mediated fermentation of dietary fibre, was analysed for effects on expression of genes related to oxidative stress in primary human colon cells. An induction of detoxifying, antioxidative genes is expected to contribute to dietary chemoprevention. Cells were treated with butyrate (3.125-50 mM; 0.5-8 h), and kinetics of uptake and survival were measured. Gene expression was determined with a pathway-specific cDNA array after treating colon epithelium stripes with nontoxic doses of butyrate (10 mM, 12 h). Changes of hCOX-2, hSOD2 and hCAT expression were confirmed with real-time polymerase chain reaction (PCR) and by measuring catalase-enzyme activity. Primary colon cells consumed 1.5 and 0.5 mM butyrate after 4- and 12-h treatment, respectively. Cell viability was not changed by butyrate during 0.5-2-h treatment, whereas cell yields decreased after 1 h. Metabolic activity of remaining cells was either increased (4 h, 50 mM) or retained at 97% (8 h, 50 mM). Expression of hCAT was enhanced, whereas hCOX-2 and hSOD2 were lowered according to both array and real-time PCR analysis. An enhanced catalase-enzyme activity was detected after 2 h butyrate treatment. Healthy nontransformed colon cells well tolerated butyrate (50 mM, 2 h), and lower concentrations (10 mM, 12 h) modulated cyclooxygenase 2 (COX-2) and catalase genes. This points to a dual role of chemoprotection, since less COX-2 could reduce inflammatory processes, whereas more catalase improves detoxification of hydrogen peroxide (H(2)O(2)), a compound of oxidative stress. Changes of this type could reduce damaging effects by oxidants and protect cells from initiation.

Increased expression of cyclooxygenase 2 contributes to aberrant renin production in connexin 40-deficient kidneys

We previously found that deletion of connexin 40 (Cx40) causes a misdirection of renin-expressing cells from the media layer of afferent arterioles to the perivascular tissue, extraglomerular mesangium, and periglomerular and peritubular interstitium. The mechanisms underlying this aberrant renin expression are unknown. Here, we questioned the relevance of cyclooxygenase-2 (COX-2) activity for aberrant renin expression in Cx40-deficient kidneys. We found that COX-2 mRNA levels were increased three-fold in the renal cortex of Cx40-deficient kidneys relative to wild-type (wt) kidneys. In wt kidneys, COX-2 immunoreactivity was minimally detected in the juxtaglomerular region, but renin expression was frequently associated with COX-2 immunoreactivity in Cx40-deficient kidneys. Treatment with COX-2 inhibitors for 1 wk lowered renin mRNA levels in wt kidneys by about 40%. In Cx40-deficient kidneys, basal renin mRNA levels were increased two-fold relative to wt kidneys, and these elevated mRNA levels were reduced to levels of untreated wt mice by COX-2 inhibitors. In parallel, renin immunoreactive areas were clearly reduced by COX-2 inhibitors such that renin expression vanished and decreased significantly in the periglomerular and peritubular extensions. Notably, COX-2 inhibitor treatment lowered plasma renin concentration (PRC) in wt kidneys by about 40% but did not affect the highly elevated PRC levels in Cx40-deficient mice. These findings suggest that aberrant renin-producing cells in Cx40-deficient kidneys express significant amounts of COX-2, which contribute to renin expression in these cells, in particular, those in the periglomerular and peritubular position. Apparently, these disseminated cells do not contribute to the enhanced renin secretion rates of Cx40-deficient kidneys.

hMLH1, hMSH2 and cyclooxygenase-2 (cox-2) in sporadic colorectal polyps

BACKGROUND

Colorectal adenomatous polyps are known as premalignant lesions. Mutations in the mismatch repair (MMR) enzymes hMLH1, hMSH2 and hMSH6 are recognized causes of hereditary non-polyposis colorectal cancer and act by inducing a mutator phenotype characterized by microsatellite instability (MSI). MSI is also detected in sporadic colorectal cancers. Cox-2 is an inducible enzyme that regulates prostaglandin synthesis and it is overexpressed at sites of inflammation, in colorectal adenomatous polyps and cancer. The aim of this study was to evaluate the immunoexpression of hMLH1, hMSH2 and Cox-2 in polyps resected through colonoscopy, and to examine their association with clinicopathological characteristics (age, gender, location, size, histology and grade of dysplasia).

PATIENTS AND METHODS

One hundred and sixty-seven colonic polyps, 6 normal colonic mucosa samples, and 23 samples of colorectal adenocarcinoma were used in this study. All patients had no family history of colorectal cancer. The samples were prospectively collected and immunostained for hMLH1, hMSH2 and Cox-2 using the ABC-immunohistochemistry technique with amplification by biotinylated tyramide. The mean age was 60.2+/-13.8 years (range 21-90 years) and 77 (55.8%) were men.

RESULTS

Tubular adenomas were present in 81.4%, tubulous-villous in 15.9%, serrated in 1.8%, and villous in 0.9%. The majority of the adenomas were located in the rectosigmoid region (63.5%), followed by ascendant in 14.2%, cecum in 7.5%, descendent in 8.2% and transverse in 6.7%. Low-grade dysplasia was detected in 59.6% of the adenomas. Loss of hMLH1 and hMLH2 immunoexpression was observed in 20% and 15.5% of the adenomas, respectively. Cox-2 expression was found in 9% of the adenomas, and in 40% of the adenocarcinomas. Moreover, Cox-2 immunoexpression was associated with the multiplicity of adenomas in the same patient (p=0.001). There was no association between marker immunoexpression and gender, age, location, size, histology or grade of dysplasia.

CONCLUSION

Loss of hMLH1 and hMLH2 immunoexpression in adenomas is relatively frequent in patients without colorectal cancer family history. Cox-2 is overexpressed in colorectal adenomatous polyps and adenocarcinomas, and its positivity in adenomas may indicate a higher risk for multiple lesions.

beta-catenin regulates multiple steps of RNA metabolism as revealed by the RNA aptamer in colon cancer cells

Nuclear beta-catenin forms a transcription complex with TCF-4, which is implicated in colon cancer development and progression. Recently, we and others have shown that beta-catenin could be a regulator of RNA splicing and it also stabilizes the cyclooxygenase-2 (COX-2) mRNA. Here, we further explored the role of beta-catenin in the RNA metabolism in colon cancer cells. To specifically modulate the subcellular functions of beta-catenin, we expressed the RNA aptamer in the form of RNA intramers with unique cellular localizations. The nucleus-expressed RNA intramer proved to be effective in reducing the protein-protein interaction between beta-catenin and TCF-4, thus shown to be a specific regulator of beta-catenin-activated transcription. It could also regulate the alternative splicing of E1A minigene in diverse colon cancer cell lines. In addition, we tested whether beta-catenin could stabilize any other mRNAs and found that cyclin D1 mRNA was also bound and stabilized by beta-catenin. Significantly, the cytoplasm-expressed RNA intramer reverted the beta-catenin-induced COX-2 and cyclin D1 mRNA stabilization. We show here that beta-catenin regulated multiple steps of RNA metabolism in colon cancer cells and might be the protein factor coordinating RNA metabolism. We suggest that the RNA intramers could provide useful ways for inhibiting beta-catenin-mediated transcription and RNA metabolism, which might further enhance the antitumorigenic effects of these molecules in colon cancer cells.

Cholinoreceptor autoantibodies in Sjögren syndrome

Previous studies have demonstrated that antibodies against cholinoreceptors of exocrine glands correlate with dry mouth in persons with primary Sjögren syndrome (pSS). The aim of the present investigation was to establish if serum IgG antibodies (pSS IgG) were able to interact with cholinoreceptors in rat submandibular gland-dependent stimulation of cyclooxygenase 2 (COX-2) mRNA expression and PGE(2) production. Our findings indicated that pSS IgG-stimulating M(3), M(4), and M(1) cholinoreceptors exerted an increase in COX-2 mRNA without affecting COX-1 mRNA expression and increased PGE(2) production. Inhibitors of phospholipase A(2), COX- s, L-type calcium channel currents, and Ca(2+)-ATPase from sarcoplasmic reticulum prevented the pSS IgG effect on PGE(2) production. An ionophore of calcium mimicked pSS IgG action, suggesting a crucial role of calcium homeostasis in the cholinoreceptor-stimulated increase in PGE(2) production. Moreover, the amounts of PGE(2) in saliva and in sera from persons with pSS were significantly higher than in pre- or post-menopausal women. These findings illustrate the importance of autoantibodies to cholinoreceptors in the generation of chronic inflammation of target tissues in SS.

Eugenosedin-A amelioration of lipopolysaccharide-induced up-regulation of p38 MAPK, inducible nitric oxide synthase and cyclooxygenase-2

In this study, we investigate the protective effects of eugenosedin-A on p38 mitogen-activated protein kinase (MAPK), inflammatory nitric oxide (NO) and cyclooxygenase-2 (COX-2) pathways in a rat model of endotoxin shock. Rats were pretreated with eugenosedin-A, trazodone, yohimbine (1 mg kg(-1), i.v.), aminoguanidine or ascorbic acid (15 mg kg(-1), i.v.) 30 min before endotoxin challenge. Endotoxaemia was induced by a single i.v. injection of lipopolysaccharide (LPS, 10 mg kg(-1)). In rats not treated with eugenosedin-A, LPS increased plasma concentrations of NO and prostaglandin E(2) (PGE(2)), and levels of p38 MAPK, inducible NO synthase (iNOS) and COX-2 proteins in the liver, lung, aorta and lymphocytes. In the pre-treated rats, eugenosedin-A not only inhibited the LPS-induced NO and PGE(2) levels but also attenuated the LPS-induced increase in p38 MAPK and iNOS levels in the liver, aorta and lymphocytes. Eugenosedin-A also reduced LPS-induced COX-2 proteins in the aorta and lymphocytes. Likewise, aminoguanidine, ascorbic acid, yohimbine and trazodone were also found to decrease NO and PGE(2) concentrations after endotoxin challenge. While aminoguanidine and ascorbic acid also attenuated the LPS-induced increase in p38 MAPK, iNOS and COX-2 proteins in the aorta and lymphocytes, trazodone and yohimbine inhibited only the increase in p38 MAPK, iNOS and COX-2 proteins in lymphocytes. Finally, eugenosedin-A (10(-10)-10(-8) M) significantly inhibited the biphasic response induced by hydrogen peroxide (10(-6)-3 x 10(-5) M) in rat denudated aorta. Taken together, the results of this study indicate that eugenosedin-A, as well as ascorbic acid, can attenuate free-radical-mediated aortic contraction and relaxation. It may therefore be able to reduce the damage caused by septic shock by inhibiting formation of p38 MAPK, iNOS, COX-2 and free radicals.

Association of COX-2 expression with corresponding active and chronic inflammatory reactions in Barrett's metaplasia and progression to cancer

AIMS

Risk reduction for Barrett's cancer in individuals taking non-steroidal anti-inflammatory drugs has been reported. Cyclooxygenase (COX)-2, one of the inhibited enzymes, is putatively involved in Barrett's cancer pathogenesis. The aim of this study was to examine a possible association between COX-2 protein expression and the development and progression of the Barrett's metaplasia-dysplasia-carcinoma sequence and the type and degree of associated inflammatory reaction.

METHODS AND RESULTS

Squamous epithelium, metaplastic, low-grade, high-grade dysplastic lesions and tumour tissue of 49 resection specimens from patients with Barrett's adenocarcinoma were immunohistochemically analysed. Active and chronic inflammatory reactions were classified according to the Updated Sydney System. Within the Barrett's sequence, a significant progressive increase in COX-2 expression was identified (P < 0.0001). The most significant differences were detected between squamous epithelium and Barrett's metaplasia (P < 0.001) and from low- to high-grade dysplasia (P < 0.0001). Active and chronic inflammation were significantly different between squamous epithelium and Barrett's metaplasia (P < 0.0001), but not during further progression in the sequence.

CONCLUSIONS

Increasing COX-2 expression in Barrett's metaplasia is significantly associated with a change in the local inflammatory reaction, but not during further progression through dysplasia to cancer. This supports the potential of a chemoprevention strategy using COX-2 inhibitors independent of the extent and type of the inflammatory reaction in Barrett's oesophagus.

Regulation of prostaglandin E synthases: Effects of siRNA-mediated inhibition of microsomal prostaglandin E synthase-1

Prostaglandin E2 (PGE2) is a key mediator involved in several inflammatory conditions. In this study, we investigated the expression and regulation of the terminal PGE2 synthesizing enzyme prostaglandin E synthases (mPGES-1, mPGES-2 and cPGES) in gingival fibroblasts stimulated with pro-inflammatory cytokines. We used siRNA knockdown of mPGES-1 to elucidate the impact of mPGES-1 inhibition on mPGES-2 and cPGES expression, as well as on PGE2 production. The cytokines TNFalpha and IL-1beta increased protein expression and activity of mPGES-1, accompanied by increased COX-2 expression and PGE2 production. The isoenzymes mPGES-2 and cPGES, constitutively expressed at mRNA and protein levels, were unaffected by the pro-inflammatory cytokines. We show for the first time that treatment with mPGES-1 siRNA down-regulated the cytokine-induced mPGES-1 protein expression and activity. Interestingly, mPGES-1 siRNA did not affect the cytokine-stimulated PGE2 production, whereas PGF(2alpha) levels were enhanced. Neither mPGES-2 nor cPGES expression was affected by siRNA silencing of mPGES-1. Dexamethasone and MK-886 both inhibited the cytokine-induced mPGES-1 expression while mPGES-2 and cPGES expression remained unaffected. In conclusion, mPGES-1 siRNA down-regulates mPGES-1 expression, and neither mPGES-2 nor cPGES substituted for mPGES-1 in a knockdown setting in gingival fibroblasts. Moreover, mPGES-1 siRNA did not affect PGE2 levels, whereas PGF(2alpha) increased, suggesting a compensatory pathway of PGE2 synthesis when mPGES-1 is knocked down.

Anti-inflammatory activity of 21(α, β)-methylmelianodiols, novel compounds from Poncirus trifoliata Rafinesque

The fruits of Poncirus trifoliata (L.) are widely used in Oriental medicine as a remedy for allergic inflammation. As a part of our program to screen medicinal plants for potential anti-inflammatory compounds, 21alpha-methylmelianodiol (21alpha-MMD) and 21beta-methylmelianodiol (21beta-MMD), which are two isomers of 21-methylmelianodiol isolated from the fruits of P. trifoliata for the first time, were found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. 21alpha-MMD and 21beta-MMD attenuated LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein expressions as well as the mRNA levels of iNOS, COX-2, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta). To investigate the mechanism involved, we examined the effect of 21alpha-MMD and 21beta-MMD on LPS-induced nuclear factor-kappaB (NF-kappaB) activation. Both 21alpha-MMD and 21beta-MMD significantly inhibited LPS-induced NF-kappaB transcriptional activity in RAW 264.7 macrophages. Moreover, the in vivo anti-inflammatory effect of 21alpha-MMD was examined in two mouse models of acute inflammation. In the carrageenan-induced paw edema model, administration of 21alpha-MMD (20 and 100 mg/kg, i.p.) dose-dependently reduced paw swelling. In addition, 21alpha-MMD significantly inhibited the dye leakage in an acetic acid-induced vascular permeability assay. Taken together, our data indicate that 21-methylmelianodiol is an important constituent of the fruit of P. trifoliata, and that the inhibition of iNOS and COX-2 expression by 21alpha-MMD and 21beta-MMD might be one of the mechanisms responsible for their anti-inflammatory effects.

Effects of Topical Antiglaucoma Medications on Corneal Epithelium as Evaluated by Gene Expression Patterns

PURPOSE

To examine the expression pattern of the stress-related genes c-fos and c-jun, which encode the 2 major components of activator protein (AP)-1, and cyclooxygenase (COX)-2 in rat corneal epithelium treated with topical antiglaucoma medications and benzalkonium chloride (BAK) preservative.

METHODS

Eighty-eight male Wistar rats were used. We instilled antiglaucoma eye drops (0.5% Timoptol, 0.005% Xalatan, or 0.12% Rescula), their chemical constituents (active ingredients), or BAK preservative (0.005%, 0.01%, or 0.02%) in 1 eye of each rat. Fellow eyes served as controls. The eyes were enucleated after various intervals. In situ hybridization and immunohistochemistry were used to detect expression of c-fos, c-jun, and COX-2.

RESULTS

Expression of c-fos, c-jun, and COX-2 was minimally observed in uninjured rat corneal epithelium. Thirty minutes to 1 hour after applying the antiglaucoma eye drops, signals for c-fos and c-jun mRNA were detected in the corneal epithelium. Ninety minutes after applying 0.005% Xalatan, 0.12% Rescula, or their chemical constituents, but not 0.5% Timoptol, COX-2 was detected in corneal epithelium. Expression of c-fos and c-jun seemed more marked with prostaglandins than with timolol. Thirty minutes to 1 hour after instillation of 0.02% BAK preservative, signals for c-fos and c-jun mRNA were detected in the corneal and conjunctival epithelium. COX-2 was not induced by 0.5% Timoptol or BAK preservative. COX-2 mRNA was not affected by applying 0.005% or 0.01% BAK preservative. Proteins of these components were also detected, indicating that each mRNA expression was followed by protein synthesis.

CONCLUSIONS

Corneal and conjunctival epithelial cells are transcriptionally activated transiently at an early phase after topical administration of antiglaucoma medications and BAK preservative. Stimulatory effects of prostaglandin drugs on corneal epithelial cells were more marked than those with timolol. Expression of COX-2 may potentially be involved in inflammatory response in the corneal epithelium.

HETEs enhance IL-1-mediated COX-2 expression via augmentation of message stability in human colonic myofibroblasts

Proinflammatory cytokines and eicosanoids are central players in intestinal inflammation. IL-1, a key cytokine associated with intestinal mucosal inflammation, induces COX-2 expression in human colonic myofibroblasts (CMF) and increased prostaglandin E(2) secretion is associated with inflammatory bowel disease (IBD) and colorectal cancer (CRC). We have previously demonstrated that IL-1alpha-induced cyclooxygenase-2 (COX-2) expression is the result of NF-kappaB- and ERK-mediated transcription, as well as COX-2 message stabilization, which depends on p38, MAPKAPK-2 (MK-2) and human antigen R (HuR) RNA binding protein activation. Lipoxygenase (LOX)-derived hydroxyeicosatetraenoic acids (HETEs) are elevated in IBD and colonic adenomas and "cross talk" has been observed between the COX and LOX pathways. Since COX-2 expression is primarily in CMFs in colonic adenomas, we examined the impact of LOX metabolites, particularly HETEs, on IL-1alpha-induced COX-2 expression in human CMFs. Although 5(S)-, 12(R)-, and 15(S)-HETEs alone had little to no effect on COX-2 expression, they enhanced IL-1-mediated COX-2 expression 3.6 +/- 0.5-fold. Studies utilizing heterogeneous nuclear RNA amplification and 5,6-dichloro-beta-d-ribofuranosylbenzimidazole treatment were undertaken to measure COX-2 transcription and message stabilization, respectively. We found that HETEs enhanced IL-1-induced COX-2 mRNA levels in CMF as the result of increased p38, MK-2, and HuR activity, increasing message stability greater than that observed with IL-1 alone. Thus HETEs can act synergistically with IL-1alpha to induce COX-2 expression in human CMFs. HETEs may play a role in both colonic inflammation and in increasing the risk of CRC in IBD independently and via induction of COX-2-mediated prostaglandin secretion.

Curcumin attenuates the release of pro-inflammatory cytokines in lipopolysaccharide-stimulated BV2 microglia

AIM

Pro-inflammatory mediators, such as prostaglandin E2 (PGE2) and nitric oxide (NO), and pro-inflammatory cytokines such as interleukin (IL)-1beta, IL-6, and TNF-alpha, play pivotal roles in brain injuries. The anti-inflammatory properties are known to be associated with significant reductions in pro-inflammatory mediators in brain injuries. In the present study we investigate whether the effects of curcumin on the production of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated BV2 microglia.

METHODS

Curcumin were administered and their effects on LPS-induced pro-inflammatory mediators were monitored by Western blotting and RT-PCR.

RESULT

Curcumin significantly inhibited the release of NO, PGE2, and pro-inflammatory cytokines in a dose-dependent manner. Curcumin also attenuated the expressions of inducible NO synthase and cyclooxygenase-2 mRNA and protein levels. Moreover, curcumin suppressed NF-kappaB activation via the translocation of p65 into the nucleus. Our data also indicate that curcumin exerts anti-inflammatory properties by suppressing the transcription of proinflammatory cytokine genes through the NF-kappaB signaling pathway.

CONCLUSION

Anti-inflammatory properties of curcumin may be useful for treating the inflammatory and deleterious effects of microglial activation in response to LPS stimulation.

COX-2 overexpression as a biomarker of early cervical carcinogenesis: a pilot study

BACKGROUND

Recent studies have demonstrated that cyclooxygenase-2 (COX-2) expression is up-regulated in a number of cancers. Selective inhibition of COX-2 offers a potential pharmacological strategy for cancer prevention. The COX-2 isoform is induced in response to inflammatory factors and is expressed in premalignant lesions, including cervical tissues. Few studies have investigated COX-2 expression as a biomarker for early cervical carcinogenesis. In this preliminary study, we assessed the variability of COX-2 overexpression in cervical premalignant lesions.

METHODS

Fifty-two patients were recruited and consented. Paired abnormal and control (normal) cervical biopsies were obtained and evaluated for high-risk human papillomavirus (HPV), inflammation, histopathological diagnosis, and COX-2 protein concentration by ELISA. Paired Student's t-test and general linear regression models were used to compare mean COX-2 protein concentrations among biopsy samples and selected risk variables.

RESULTS

Forty-seven of fifty-two paired biopsies were evaluated. COX-2 protein concentrations were 4.9-fold greater in abnormal biopsies (CIN 1 and CIN 2) than normal biopsies. COX-2 was also significantly increased in inflammation-positive biopsies. No significant association was found between COX-2 levels and HPV high-risk positivity, age, parity, STI history, or hormonal contraceptive use, but the sample size was small.

CONCLUSIONS

These results suggest that COX-2 induction begins in the premalignant phase of cervical carcinogenesis and is correlated with inflammation. A trial using a much larger number of specimens will allow further development of our understanding of COX-2 as a biomarker for use in chemoprevention trials.

Endothelial-specific knockdown of interleukin-1 (IL-1) type 1 receptor differentially alters CNS responses to IL-1 depending on its route of administration

Interleukin-1 (IL-1) has been implicated as a critical mediator of neuroimmune communication. In the brain, the functional receptor for IL-1, type 1 IL-1 receptor (IL-1R1), is localized primarily to the endothelial cells. In this study, we created an endothelial-specific IL-1R1 knockdown model to test the role of endothelial IL-1R1 in mediating the effects of IL-1. Neuronal activation in the hypothalamus was measured by c-fos expression in the paraventricular nucleus and the ventromedial preoptic area. In addition, two specific sickness symptoms, febrile response and reduction of locomotor activity, were studied. Intracerebroventricular injection of IL-1 induced leukocyte infiltration into the CNS, activation of hypothalamic neurons, fever, and reduced locomotor activity in normal mice. Endothelial-specific knockdown of IL-1R1 abrogated all these responses. Intraperitoneal injection of IL-1 also induced neuronal activation in the hypothalamus, fever, and reduced locomotor activity, without inducing leukocyte infiltration into the brain. Endothelial-specific knockdown of IL-1R1 suppressed intraperitoneal IL-1-induced fever, but not the induction of c-fos in hypothalamus. When IL-1 was given intravenously, endothelial knockdown of IL-1R1 abolished intravenous IL-1-induced CNS activation and the two monitored sickness symptoms. In addition, endothelial-specific knockdown of IL-1R1 blocked the induction of cyclooxygenase-2 expression induced by all three routes of IL-1 administration. These results show that the effects of intravenous and intracerebroventricular IL-1 are mediated by endothelial IL-1R1, whereas the effects of intraperitoneal IL-1 are partially dependent on endothelial IL-1R1.

Murine trefoil factor 3 does not directly modulate LPS-mediated dendritic cell function

Peptides of the trefoil factor family (TFF) are expressed along the gastro-intestinal tract. They protect mucous epithelia from damage and contribute to mucosal repair, which is essential for preventing inflammation. Moreover, it has been suggested that TFF2 and TFF3, in particular, play a role in regulating immune responses. Depending on their activation status, dendritic cells (DC) can initiate either tolerance or immunity. This study, by comparing LPS-induced maturation of mTFF3-treated DC and non-treated DC, investigated whether murine TFF3 directly regulated DC function. mTFF3-treated DC and non-treated DC did not differ phenotypically or functionally. Both populations expressed, both before and after LPS-stimulation, similar levels of co-stimulatory molecules and cytokines, and were both efficient stimulators of T-cells. Our results suggest that mTFF3 does not govern immune responses on the level of DC function.

Puromycin induces reversible proteinuric injury in transgenic mice expressing cyclooxygenase-2 in podocytes

Previous studies from our own group and others have demonstrated that cyclooxygenase-2 (COX-2) inhibitors could reduce proteinuria in some experimental models of progressive renal disease. To investigate a possible role of COX-2 in podocytes during the course of self-limited glomerular injury, we administered puromycin nucleoside (PAN) on day 1 (15 mg/100 g BW) and day 3 (30 mg/100 g BW) to wild-type and transgenic mice with podocyte-specific COX-2 expression driven by a nephrin promoter. An additional group received both PAN and the COX-2-specific inhibitor, SC58236 (6 mg/l in drinking water). There was no significant difference in the albumin (microg)/creatinine (mg) ratio between wild-type (26.3 +/- 4.2, n = 8) and transgenic (28.9 +/- 2.3, n = 8) mice under baseline conditions. PAN induced significant albuminuria only in the transgenic mice with a peak at day 3: 72.1 +/- 8.9 microg/mg creatinine (n = 12, p < 0.05, compared with basal level), which remitted by day 10 (37.4 +/- 4.4 microg/mg, n = 7, p < 0.05, compared with day 3). Electron microscopy demonstrated that PAN caused 56.7 +/- 4.2% foot process effacement in transgenic mice compared with 38.8 +/- 4.1% in wild type at day 3. PAN increased immunoreactive COX-2 in glomeruli from transgenic mice (day 3: 1.47 +/- 0.08 fold; day 10: 1.25 +/- 0.16 fold, n = 5-9, p < 0.05 compared with basal level), which was restricted to podocytes. Real time PCR indicated that endogenous COX-2 mRNA increased (2.6 +/- 0.1 fold of wild-type control at day 3 and 2.2 +/- 0.2 at day 10, n = 4, p < 0.05), while the nephrin-driven COX-2 mRNA was unchanged. Nephrin mRNA and protein expression were decreased by PAN in the transgenic mice. The COX-2-specific inhibitor, SC58236, reduced foot process effacement in transgenic mice administered PAN to 21.7 +/- 5.2% and significantly reduced the albuminuria at day 3 (42.2 +/- 3.8, n = 13, p < 0.05 compared with untreated) without significantly altering COX-2 expression. In summary, in transgenic mice with podocyte COX-2 overexpression, PAN increased albuminuria and induced foot process fusion. Thus, increased COX-2 expression increased podocyte susceptibility to further injury.

Expression of HuR is associated with increased cyclooxygenase-2 expression in uterine cervical carcinoma

The human family embryonic-lethal abnormal vision-like protein Hu antigen R (HuR) serves as a messenger RNA (mRNA)-binding protein and stabilizes a certain group of cellular mRNAs that contain adenylate/uridylate-rich elements in their 3-untranslated region. The HuR is predominantly located in the nucleus, but it shuttles between the nucleus and the cytoplasm. In the cytoplasm, it can stabilize certain transcripts. Reportedly, the mRNA of cyclooxygenase-2 (COX-2) can be stabilized by HuR in breast, ovary, colon, stomach, lung, and brain cancers. We investigated the expression of HuR and COX-2 in 308 primary uterine cervical carcinomas using immunohistochemistry. Nuclear HuR expression was seen in 280 (90.9%) of the cases, and cytoplasmic HuR expression was observed in 61 (19.8%) of the cases. The expression of nuclear HuR was significantly associated with stage (P = 0.031). We found that 135 patients (43.8%) showed positive reaction for the COX-2 protein. In the COX-2 positive cases, nuclear HuR expression was higher, but the difference was not statistically significant. Cytoplasmic HuR expression was significantly associated with tumor size (P = 0.029), stage (P = 0.005), and lymphatic/vascular invasion (P < 0.001). Considering only squamous cell lesions (carcinoma in situ, microinvasive squamous cell carcinoma [SCC], and invasive SCC), the cytoplasmic expression of HuR significantly increased in invasive SCC compared with microinvasive SCC or carcinoma in situ (P = 0.005). Cytoplasm HuR expression correlated with COX-2 (P < 0.001). There was no significant correlation between HuR (nuclear or cytoplasmic) expression and patient survival. Our results suggest that the cytoplasmic overexpression of HuR is associated with uterine cervical carcinomas with aggressive clinicopathologic features and that HuR might contribute to the stabilization of COX-2 mRNA in some uterine cervical carcinomas.