Inhibitor Nimesulide Research Articles

COX‐1 in Addition to COX‐2 Mediates Ischemic Preconditioning

COX-2 is an important mediator of cardiovascular protection after ischemia and reperfusion. It is known that COX-2 has a role in ischemic preconditioning (IP). The beneficial actions of COX-2 appear to be mediated by the synthesis of PGE2 and/or PGI2. Little is known about the actions of COX-1 in IP. This study was designed to determine the effects of COX-1 inhibition on infarct size after IP. Male New Zealand white rabbits were administered SC-560 (0.3 mg/kg or 1 mg/kg), nimesulide (5mg/kg), or vehicle intravenously prior to IP, 30 minutes of ischemia and 4 hours of reperfusion. IP reduced myocardial infarct size (10.5+/−2.6% vs. control 40.4+/−2.6%; p < 0.001) whereas treatment with the COX-2 inhibitor nimesulide abolished the protective effects of IP (40.3+/−3.1% p < 0.001 vs. IP). Treatment with the COX-1 inhibitor SC-560 reduced the protective effects of IP at a dose of 1 mg/kg (30.2+/−2.8%; p < 0.01), but not at 0.3 mg/kg (23.7+/−3.1%). The data suggest that endothelial COX-1 may also play a role in IP. It is likely that COX-2 plays a larger role because of its inducible activation, but the ability of COX-1 to produce protective PGE2 and/or PGI2 should not be overlooked. A recent study (Mitchell et al. 2006) suggests that endothelial COX-1, a source of PGI2, is more susceptible to inhibition by selective COX-2 inhibitors than is platelet COX-1. This would explain the reduced efficacy of IP by both the selective COX-1 and COX-2 inhibitors.

COX‐2 inhibitor protects rat hearts against oxidative stress through endothelial function improvement and NO enhancement

The study was to explore whether cyclooxygenase 2 (COX-2) inhibitor could protect the myocardial function against oxidative stress injury in rat hearts and to investigate its mechanisms. Isolated rat hearts perfused by the Langendorff method were exposed to H2O2 (140¦ÌM/L), after that coronaries were precontracted with U-46619, and then the response to the endothelium-dependent vasodilator 5-HT and endothelium-independent SNP were evaluated. Exposure hearts to H2O2for 20 min, systolic function were reduced. Pretreatment with COX-2 inhibitor nimesulide (5¦ÌM/L) enhanced the LVDP and ¡ÀdP/dtmax, which could be abolished by NOS inhibitor L-NAME. The vasodilatation produced by 5-HT and SNP in H2O2group was significantly less than in that of control group. Pretreatment with nimesulide antagonized the decrease in endothelium-dependent vasodilatation, but had no effect on the decline in endothelium-independent vasodilatation. The concentration of 6-keto PGF1¦Á was no different among all groups. These data suggest that nimesulide could improve myocardial function in rat hearts suffered from oxidative stress. The mechanisms may be through endothelial function improvement and NO enhancement, but not via inhibiting COX-2 activity. (Project Supported by the National Natural Science Foundation of China (NO. 30400094) ).

Post‐ischaemic treatment with the cyclooxygenase‐2 inhibitor nimesulide reduces blood–brain barrier disruption and leukocyte infiltration following transient focal cerebral ischaemia in rats

Several studies suggest that cyclooxygenase (COX)-2 plays a pivotal role in the progression of ischaemic brain damage. In the present study, we investigated the effects of selective inhibition of COX-2 with nimesulide (12 mg/kg) and selective inhibition of COX-1 with valeryl salicylate (VAS, 12-120 mg/kg) on prostaglandin E(2) (PGE(2)) levels, myeloperoxidase (MPO) activity, Evans blue (EB) extravasation and infarct volume in a standardized model of transient focal cerebral ischaemia in the rat. Post-ischaemic treatment with nimesulide markedly reduced the increase in PGE(2) levels in the ischaemic cerebral cortex 24 h after stroke and diminished infarct size by 48% with respect to vehicle-treated animals after 3 days of reperfusion. Furthermore, nimesulide significantly attenuated the blood-brain barrier (BBB) damage and leukocyte infiltration (as measured by EB leakage and MPO activity, respectively) seen at 48 h after the initial ischaemic episode. These studies provide the first experimental evidence that COX-2 inhibition with nimesulide is able to limit BBB disruption and leukocyte infiltration following transient focal cerebral ischaemia. Neuroprotection afforded by nimesulide is observed even when the treatment is delayed until 6 h after the onset of ischaemia, confirming a wide therapeutic window of COX-2 inhibitors in experimental stroke. On the contrary, selective inhibition of COX-1 with VAS had no significant effect on the evaluated parameters. These data suggest that COX-2 activity, but not COX-1 activity, contributes to the progression of focal ischaemic brain injury, and that the beneficial effects observed with non-selective COX inhibitors are probably associated to COX-2 rather than to COX-1 inhibition.

Enhancement of the photodynamic effects on human oral squamous cell carcinoma cell lines by treatment with calcipotriol

Summary Background 5-Aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) for patients with skin and oral diseases is a highly sophisticated procedure, but the incidence of disease recurrence after treatment with ALA-based PDT is somewhat alarming. Calcipotriol, an analogue of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), has been reported to regulate the proliferation and differentiation of keratinocytes. Objective In order to obtain even greater efficacy of ALA-based PDT, we investigated the synergistic effects of calcipotriol as an adjunct to ALA-based PDT for human oral squamous cell carcinoma (SCC) cell lines. Methods Intracellular protoporphyrin IX (PpIX) converted from exogenous ALA in SCC cell lines treated with/without calcipotriol was measured by a fluorescencemeter. Then, the in vitro effects of calcipotriol, the cyclooxygenase (COX)-2 selective inhibitor (nimesulide), ALA-based PDT and their combination on two SCC cell lines, HSC-2 (a COX-2 high expresser) and HSC-4 (a COX-2 non-expresser), were determined by MTT assay and double-staining for annexin V and propidium iodide. Results The concentration of intracellular PpIX was increased in four of the eight SCC cell lines (50%) treated with calcipotriol. The greatest alteration of intracellular PpIX was found in HSC-4 (1.9-fold). The combination of calcipotriol and ALA-based PDT remarkably inhibited cellular proliferation and induced cellular death of both HSC-2 and HSC-4. Whereas, this morphological damage was more serious in HSC-4 than in HSC-2. Furthermore, these effects were almost equivalent to the synergistic effect of the combination of nimesulide and ALA-based PDT on HSC-2. Conclusions The present study suggests that treatment with calcipotriol enhances the photodynamic effects on SCC via the accumulation of exogenous ALA-dependent PpIX.

Selective cyclooxygenase-2 inhibitors stimulate glucose transport in L6 myotubes in a protein kinase Cδ-dependent manner

Selective inhibitors of cyclooxygenase-2 (prostaglandin-endoperoxide synthase-2; COX-2) augment the rate of hexose uptake in myotubes by recruiting glucose transporter-4 (GLUT-4) to the plasma membrane in an insulin- and AMPKα-independent manner [Alpert E, Gruzman A, Lardi-Studler B, Cohen G, Reich R, Sasson S. Cyclooxygenase-2 (PTGS2) inhibitors augment the rate of hexose transport in L6 myotubes in an insulin- and AMPKα-independent manner. Diabetologia 2006;49:562–70]. We aimed at elucidating the molecular interactions that mediate this effect of COX-2 inhibitors in L6 myotubes. The effects of the inhibitors niflumic acid, nimesulide and rofecoxib on activities and phosphorylation state of key proteins in the insulin transduction pathway were determined. These inhibitors did not induce specific tyrosine phosphorylation in IRS-1, could not assemble a functional IRS-PI3K-PKB/Akt complex and did not activate GSK3α/β, JNK1/2, ERK1/2, p38-MAPK or c-Cbl by site-specific phosphorylation(s). Yet, like insulin, they activated mTOR and induced downstream threonine phosphorylation in p70S6K and 4EBP1. However, rapamycin, which inhibits mTOR enzymatic activity, did not interfere with COX-2 inhibitor-induced stimulation of hexose uptake in myotube. Thus, mTOR activation was not required for COX-2 inhibitor-dependent augmentation of hexose transport in myotubes. Because PKCδ has also been shown to activate mTOR, we asked whether COX-2 inhibitors activate mTOR by a prior activation of PKCδ. Indeed, all three inhibitors induced tyrosine phosphorylation in PKCδ and stimulated its kinase activity. Moreover, pharmacological inhibition of PKCδ or the expression of a dominant-negative form of PKCδ in myotubes completely abolished COX-2 inhibitor-dependent stimulation of hexose uptake. This study shows that selective COX-2 inhibitors activate a unique PKCδ-dependent pathway to increase GLUT-4 abundance in the plasma membrane of myotubes and augment the rate of hexose transport.

Cyclooxygenase-2 inhibitor, nimesulide, improves radiation treatment against non-small cell lung cancer both in vitro and in vivo

Lung cancer is the leading cause of cancer-related deaths in the United States. Despite improvements in radiation, surgery and chemotherapy the 5 year survival statistics of non-small cell lung cancer (NSCLC) have improved little over the past two decades. It has been proposed that NF-kappaB is a participant in the cytoprotection against several redox-mediated therapeutic agents including ionizing radiation. Cyclooxygenase-2 (COX-2) inhibition has become an attractive target for enhancing the efficacy of radiation and chemotherapy. Numerous mechanistic pathways have been proposed as the means through which COX-2 inhibition enhances the efficacy of radiation. We hypothesize that the COX-2 inhibitor, nimesulide, will improve the efficacy of radiation therapy (RT), at least in part, via the suppression of NF-kappaB mediated cytoprotective pathways. In this study we used the COX-2 inhibitor nimesulide to improve the efficacy of RT when measured by tumor regrowth assays in vivo and clonegenic survival in vitro. For the in vivo assay, A549 tumor cells representing NSCLC were subcutaneously injected into the right flanks of female athymic nude mice (n=10/group). Mice were given nimesulide via drinking water at a concentration of 5 microg/g body weight (b.w.) and the water was replenished daily. Tumors were treated with 30 Gy fractionated radiation and measured bi-weekly. For our in vitro study, clonogenic survival assays were evaluated to determine the effect of nimesulide, radiation, and the combination. The NF-kappaB mediated mechanism of nimesulide was measured by Western blot analysis of NF-kappaB target genes, MnSOD and survivin. In vivo, mice that received combined treatments of 5 microg/g b.w. nimesulide and 30 Gy radiation (3 Gy/fraction, 10 daily fractions) had significant reduction in tumor size in comparison to the 30 Gy radiation control group (p<0.05). In vitro, nimesulide alone produced a significant decrease in clonogenic survival at doses from 0-300 microM. Nimesulide demonstrated an additive effect in combination with radiation. Nimesulide alone reduced MnSOD and survivin protein levels in a dose-dependent manner. 6 Gy radiation caused an initial elevation of MnSOD protein levels which was inhibited by prior treatment of nimesulide suggesting an inhibition of radiation induced NF-kappaB target genes. These results support the hypothesis that COX-2 inhibitors such as nimesulide can increase the efficacy of radiation therapy. In vitro, our results suggest that the radiosensitization of A549 tumor cells by nimesulide is mediated by the suppression of NF-kappaB-mediated, radiation-induced cytoprotective genes.

Ontogeny of chicken ductus arteriosus response to oxygen and vasoconstrictors

The present study aimed to characterize the contractile reactivity of the chicken ductus arteriosus (DA) from the last stage of prenatal development and throughout the perinatal period. Isolated DA rings from 15-day, noninternally-pipped 19-day, and externally-pipped 21-day embryos were studied using myograph techniques. On embryonic day 15, the chicken DA did not respond to O(2) (0 to 21%), norepinephrine (NE), or phenylephrine (Phe) but contracted in response to high-K(+) solution, the inhibitor of voltage-gated channels 4-aminopyridine, U-46619, and endothelin (ET)-1. These responses increased with advancing incubation age. Contractile responses to O(2), NE, and Phe were present in the 19- and 21-day embryo. Oxygen-induced contraction was restricted to the pulmonary side of the DA and was augmented by the nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester and the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and reduced by the peptidic ET(A) and ET(B)-receptor antagonist PD-142,893. Transmural electrical stimulation of nerves, the nonselective cyclooxygenase (COX) inhibitor indomethacin, the COX-1 inhibitor valeryl salicylate, the COX-2 inhibitor nimesulide, the inhibitor of ATP-sensitive K(+) channels glibenclamide, and the inhibitor of Ca(2+)-activated K(+) channels tetraethylammonium did not cause contraction of the DA rings at any age. We conclude that transition to ex ovo life is accompanied by dramatic changes in chicken DA reactivity. At 0.7 incubation, excitation-contraction and pharmacomechanical coupling for several contractile agonists are already present, whereas the constrictor effects of O(2) and cathecolamines appear later in development and are located in the pulmonary side of the DA.

Cyclooxygenase-2 inhibition normalizes arterial blood pressure in CYP1A1-REN2 transgenic rats with inducible ANG II-dependent malignant hypertension

The present study was performed to determine the effects of cyclooxygenase (COX)-1 and COX-2 inhibition on blood pressure and renal hemodynamics in transgenic rats with inducible malignant hypertension [strain name: TGR(Cyp1a1Ren2)]. Male Cyp1a1-Ren2 rats (n = 7) were fed a normal diet containing the aryl hydrocarbon, indole-3-carbinol (I3C; 0.3%), for 6-9 days to induce malignant hypertension. Mean arterial pressure (MAP) and renal hemodynamics were measured in pentobarbital sodium-anesthetized Cyp1a1-Ren2 rats during control conditions, following administration of the COX-2 inhibitor nimesulide (3 mg/kg iv), and following administration of the nonspecific COX inhibitor meclofenamate (5 mg/kg iv). Rats induced with I3C had higher MAP than noninduced rats (n = 7; 188 +/- 6 vs. 136 +/- 4 mmHg, P < 0.01). There was no difference in renal plasma flow (RPF) or glomerular filtration rate (GFR) between induced and noninduced rats. Nimesulide elicited a larger decrease in MAP in hypertensive rats (188 +/- 6 to 140 +/- 8 mmHg, P < 0.01) than in normotensive rats (136 +/- 4 to 113 +/- 8 mmHg, P < 0.01). Additionally, nimesulide decreased GFR (0.9 +/- 0.13 to 0.44 +/- 0.05 ml.min(-1).g(-1), P < 0.05) and RPF (2.79 +/- 0.27 to 1.35 +/- 0.14 ml.min(-1).g(-1), P < 0.05) in hypertensive rats but did not alter GFR or RPF in normotensive rats. Meclofenamate further decreased MAP in hypertensive rats (to 115 +/- 10 mmHg, P < 0.05) but did not decrease MAP in normotensive rats. Meclofenamate did not alter GFR or RPF in either group. These findings demonstrate that COX-1- and COX-2-derived prostanoids contribute importantly to the development of malignant hypertension in Cyp1a1-Ren2 transgenic rats. The data also indicate that COX-2-derived vasodilatory metabolites play an important role in the maintenance of RPF and GFR following induction of malignant hypertension in Cyp1a1-Ren2 transgenic rats.

Inhibition of human Neuroblastoma in SCID mice by low-dose of selective Cox-2 inhibitor Nimesulide

Neuroblastoma is the most common solid tumor of infants and carries a poor prognosis especially in advanced stages. The present recommended therapies carry a high risk of side effects that is associated with long-term morbidity. We evaluated the efficacy of a low dose of the selective cyclooxygenase-2 inhibitor Nimesulide in preventing human Neuroblastoma tumor growth in Severe Combined Immune-deficient mice. Mice containing established tumors (SH-SY5Y cells) treated with 20 mg/kg Nimesulide every 4th day beginning on day 1 of cell injections resulted in a 65% reduction of tumor growth compared to the DMSO treated control mice (P<0.05) but did not significantly reduce tumor growth when Nimesulide was started once tumors reached 1 cm. There was a reduction in the level of cyclooxygenase-2 protein and induction of effecter caspases in tumors treated with Nimesulide. However, there was no change in the levels of X-Inhibitor-of-Apoptosis-Protein, Smac/Diablo, or proteins of the PI3/Akt pathway following Nimesulide treatment. In Conclusion, low doses of Nimesulide can potentially be used as a chemopreventive agent for human Neuroblastoma.

Cyclooxygenase‐1 and ‐2 inhibition alter hypothalamic‐pituitary‐adrenal axis (HPA) activity and COX expression in fetal brain.

In fetal sheep, reflex responses to hypotension are in part mediated by generation of prostaglandins (PG) in the CNS. We have previously demonstratd that inhibition of COX1 reduces the responsiveness of the fetal HPA to hypotension and increases expression of COX2 in specific regions of the fetal CNS. We hypothesized that generation of PG alters the transcription of COX2. The present study was designed to test this hypothesis. Chronically catheterized twin fetal sheep received cerebral ventricular infusions of inhibitor or vehicle. We used either the COX2 inhibitor nimesulide (NIM) at 1mg (HD) or 10 ug/day (LD), or the COX1 inhibitor resveratrol (RES) at 1 mg/day. Blood samples were collected to measure fetal blood gases, proopiomelanocortin (POMC), ACTH, and cortisol. After 5 days, fetal hypothalami and pituitaries were harvested, and COX1 and 2 mRNA were analyzed by real-time PCR. Arterial blood gases were unchanged by HD nimesulide or resveratrol. LD nimesulide significantly decreased pO2 of vehicle treated fetuses. HD NIM significantly reduced hypothalamic COX1 and 2 mRNA, but did not alter pituitary levels. COX1 and 2 were unchanged in the RES and LD NIM groups. Hypothalamic AVP, CRH, and POMC mRNA levels were unchanged in all groups. Plasma ACTH, POMC, and cortisol concentrations were unchanged in the HD NIM group, yet RES and LD NIM treatment significantly reduced plasma cortisol without changing POMC or ACTH. We conclude that blockade of COX2 with HD NIM alters the expression of COX1 and 2 mRNA; and 2) unstimulated fetal ACTH secretion is not altered by blockade of CNS COX isoforms, although adrenal sensitivity to ACTH appears to be influenced by both COX1 and 2 activity in the CNS. Supported by HD42135 and a Predoctoral Fellowship from the American Heart Association.

Etodolac, a selective cyclooxygenase-2 inhibitor, inhibits liver metastasis of colorectal cancer cells via the suppression of MMP-9 activity

Synchronous or metachronous liver metastasis occurs in approximately 15% of colorectal cancer patients and is an important negative prognostic factor. We therefore need an effective therapy to prevent metastasis. It has become apparent that cyclooxygenase (COX)-2 plays an important role in cancer growth, invasion and metastasis and that there is potential for chemoprevention via inhibition of these processes. We injected colon 26, a colorectal cancer cell line, in CDF1 mouse spleen and, from the following day, two kinds of COX-2 inhibitor (etodolac and nimesulide) were administered orally. Two weeks later, the animals were sacrificed, the liver was excised, and we counted the number of metastatic nodules on the liver surface. In addition, COX-2 mRNA, matrix metalloproteinase (MMP)-9 mRNA, and tissue inhibitor of MMP (TIMP)-1 mRNA of cancer tissue were measured by means of real-time RT-PCR. The number of metastatic nodules on the liver surface was significantly lower in the etodolac-treated group than in controls (p=0.001), but no significant difference was noted in the nimesulide-treated group. The expression of COX-2 mRNA was also significantly lower in the etodolac-treated group than in controls (p=0.04), but not in the nimesulide-treated group. In addition, the expression of MMP-9 mRNA was significantly lower in the etodolac group than in controls (p=0.02), but not in the nimesulide group. Among the groups, there were no significant differences in TIMP-1 mRNA. Expression of COX-2 mRNA and MMP-9 mRNA correlated significantly (r=0.78, p=0.001), but there was no correlation between either COX-2 mRNA and TIMP-1 mRNA expression or between MMP-9 mRNA and TIMP-1 mRNA expression. These findings indicate that the selective COX-2 inhibitor, etodolac, suppresses liver metastasis by reducing MMP-9 activity.

Cyclooxygenase-2 (PTGS2) inhibitors augment the rate of hexose transport in L6 myotubes in an insulin- and AMPKα-independent manner

Some cyclooxygenase-2 (COX2, also known as prostaglandin-endoperoxide synthase 2 [PTGS2]) inhibitors have been shown to increase insulin sensitivity in man or induce hypoglycaemic episodes when overconsumed or taken in combination with oral hypoglycaemic drugs. These side-effects and their impact on patients are not always recognised in routine clinical practice. We investigated whether these side-effects of COX2 (PTGS2) inhibitors result from stimulation of the glucose transport system in skeletal muscle cells. L6 myotube cultures were used to study effects of COX2 (PTGS2) inhibitors on the glucose transport system and their relationship to PTGS2 expression, insulin action and AMP-activated protein kinase alpha (AMPKalpha) activity. The inhibitors niflumic acid, nimesulide and rofecoxib increased the rate of hexose uptake in L6 myotubes in the absence of insulin and in a dose- and time-dependent manner. They did this by increasing the total cell content of member 4 of the solute carrier family 2 (SCLC2A4, previously known as glucose transporter 4 [GLUT4]) (but not SCLC2A1 [previously known as GLUT1]) mRNA and protein and the amount of it in the plasma membrane. AMPKalpha was not involved in the latter effect since the inhibitors did not activate it. In addition, none of the inhibitors modulated the rate of hexose transport in vascular endothelial and smooth muscle cells expressing PTGS2 and SCLC2A1. Prostaglandin-endoperoxide synthase 1 (also known as cyclooxygenase 1) inhibitors (acetylsalicylic acid and indomethacin) did not alter the rate of hexose uptake and SCLC2A4 subcellular distribution in L6 myotubes. This study suggests that certain COX2 (PTGS2) inhibitors can alter glucose homeostasis in vivo by stimulating glucose uptake in skeletal muscles that express PTGS2.

Use of Nonsteroidal Anti-Inflammatory Drugs in Patients with Aspirin Hypersensitivity

This article provides information on the pathogenesis of aspirin hypersensitivity, cross-sensitivity, and cross-tolerance of different NSAIDs in patients with respiratory types of reactions. Hypersensitivity to aspirin may affect 5-20% of patients with chronic asthma and an unknown fraction of patients with chronic urticaria-angioedema. These patients develop cross-reactions to other, chemically non-related, NSAIDs with strong inhibitory activity towards cyclo-oxygenase (COX)-1 (e.g. indomethacin, naproxen, ketoprofen). Avoidance of aspirin and all cross-reacting NSAIDs as well as education of patients are crucial. As an alternative antipyretic or analgesic drug, aspirin-sensitive asthmatic patients may take acetaminophen (paracetamol) in low or moderate doses (<1000mg). Preferential COX-2 inhibitors (nimesulide, meloxicam) are tolerated by the majority but not all hypersensitive patients. Selective COX-2 inhibitors (celecoxib and rofecoxib [withdrawn from the market]) are well tolerated by almost all aspirin-sensitive asthmatic patients. In patients with coronary artery disease requiring treatment with aspirin, desensitization to aspirin may be an alternative approach. Thus, for the majority of patients with asthma and hypersensitivity to aspirin or other NSAIDs, an alternative anti-inflammatory drug can be found. However, in each individual case physicians must consider the choice of an alternative NSAID carefully.

Inhibition of cyclooxygenase as potential novel therapeutic strategy in N141I presenilin-2 familial Alzheimer's disease

The present study was designed to further explore the potential cause/effect relationship between the expression of both the N141I presenilin (PS)2 mutant familial Alzheimer's disease (FAD) gene and cyclooxgenase (COX) in respect to the mechanism associated with programmed cell death in Alzheimer's disease (AD). We found that expression of mutant N141I PS2 resulting in apoptotic cell death in H4 neuronal cells coincided with >4-fold induction in the expression of the inducible form of COX-2, but not the constitutive COX-1. Moreover, we found that the expression of the N141I PS2 FAD gene strongly promoted (>2-fold) glycogen synthase kinase (GSK)-3beta activity coincidental with a reduction in the level of beta-catenin translocated from the cytoplasmic to the nuclear compartment. Most interestingly, we found that inhibition of COX-2-mediated generation of prostaglandin (PG)-E2 in H4 neuronal cells with the preferential COX-2 inhibitor nimesulide protects against N141I PS2-mediated apoptotic cell death coincidental with an inhibition of GSK-3beta activity and subsequent normalization of beta-catenin cellular distribution. The clinical relevance of this finding was confirmed by the evidence that COX-2 protein and PG-E2 concentrations were selectively increased >2-fold in the cerebral cortex of subjects harboring the N141I PS2 FAD mutation relative to wild-type PS2 AD cases. This study demonstrates for the first time that COX-2 may be a downstream effector of mutant N141I PS2-mediated apoptotic cell death and that inhibition of COX-2 may neuroprotect in AD through modulation of a GSK-3beta-beta-catenin-mediated response. The study provides support for the potential pharmacogenomic identification of N141I PS2 FAD cases that might preferentially benefit from inhibition of COX-2 during the progression of clinical dementia.

Inhibition of cytotoxicity of cisplatin by cyclooxygenase-2 inhibitor nimesulide in head and neck cancer cell lines

Although head and neck cancer is a common malignancy, investigations have not yet improved the poor prognosis of patients. Therefore, it is important to find new cancer treatment modalities. Recent studies showed that cyclooxygenase, especially its isoform cyclooxygenase-2, is involved in tumorigenesis, tumor growth and metastasis. Inhibition of this enzyme by cyclooxygenase inhibitors has been shown to be antiproliferative in numerous cancer cell lines. The aim of this study was to investigate if the selective cyclooxygenase-2 inhibitor nimesulide could enhance cytotoxicity of the standard chemotherapeutic agent cisplatin. Head and neck squamous cell cancer cells were incubated with nimesulide and/or cisplatin, and counted after 24, 48 and 72 h treatment. Visualization of apoptotic cells was done by immunohistochemistry. We demonstrated that nimesulide inhibits the cytotoxic effect of cisplatin in HNSCC cells. Therefore, COX-2 inhibitor nimesulide may not be a good partner for cisplatin in combination therapy for cancer.

Modulatory Effect of Nimesulide on Apomorphine Induced Stereotypy cind MK-801 Induced Hyperlocomotion

Cyclooxygenase-2 is expressed on neurons in structures critically involved in the pathology of schizophrenia such as hippocampus and amygdala. With this background, the present study was designed to explore the possible effect of COX-2 inhibitor nimesulide on apomorphine-induced stereotypy and MK-801-induced hyperlocomotion in animals. Stereotypy was induced by injecting apomorphine (1 mg/kg, i.p). Mean rearing, sniffing and licking response was recorded. Locomotor activity was measured by using an actophotometer. Nimesulide (2.5–10mg/kg, i.p) was tested on these two models. To see the mechanism of action, nimesulide was combined with dopaminergic modulator apomorphine (1 mg/kg) or NMDA modulator MK-801 (0.1 mg/kg) in mice. Nimesulide was effective in combating apomorphine-induced compulsive behavior. Nimesulide also decreased the locomotor activity per se. From the above study, we concluded that nimesulide decreased apomorphine-induced stereotypy and MK-801-induced hyperlocomotion. Therefore, nimesulide may have potential adjuvant role in the drug therapy of schizophrenia. doi: 10.5214/ans.0972.7531.2005.120402

The effect of selective cyclooxygenase-2 inhibitor nimesulide on breast cancer induced by dimethylbenzoic acid in rats

To study the effect of nimesulide (NIM) on the tumorigenesis of mammary tumors induced by dimethylbenzoic acid (DMBA), and to investigate possible mechanisms of NIM against tumors. The studied rats were randomly divided into four groups: experimental control group, NIM group, diet and drug of NIM control group. The incidence of mammary tumor was observed. RT-PCR, Western blot were used to detect 8 cancerous tissues in every group, randomly. The expressions of cylooxygenase-2 (COX-2) were assessed by immunohistochemistry. The levels of prostaglandin E(2) (PGE(2)) in blood plasma and tumor tissues were determined by means of radio-immunity assay. The apoptosis index and the proliferation index were evaluated by TUNEL assay, immunohistochemical staining for proliferating cell nuclear antigen (PCNA), respectively. The incidence of mammary tumor was 69.2% in experimental control group, 40.3% in NIM group. There was obviously decreased incidence in NIM group; The expressions of COX-2 mRNA and protein were significantly down-regulated in NIM group compared with experimental control group. The increased levels of PGE(2) synthesis in blood plasma and tumor tissues were significantly decreased by administering NIM (P < 0.05). The apoptosis index was obviously higher, the proliferation index was markedly less in NIM group than experimental control group. Nimesulide could inhibit the tumorigenesis and development of DMBA-induced mammary tumors by inhibition of proliferation and induction of apoptosis. COX-2 and COX-2-mediated PGE(2) synthesis may play an important role in rat DMBA-induced breast cancer.

INVOLVEMENT OF ENDOTHELIAL CYCLO‐OXYGENASE METABOLITES IN NORADRENALINE‐INDUCED CONTRACTION OF RAT CORONARY ARTERY

1. Noradrenaline (NA; 0.3 micromol/L) caused a contraction of the rat coronary artery that markedly increased in the presence of the nitric oxide synthase (NOS) inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME; 100 micromol/L) and arachidonic acid (1 micromol/L; P < 0.05). 2. The present experiments attempted to elucidate the endothelium dependency of the contraction and to pharmacologically characterize the factors involved in the contraction induced by NA (0.3 micromol/L) in the presence of L-NAME and arachidonic acid in ring preparations of the rat coronary artery. 3. The NA (0.3 micromol/L)-induced contraction was attenuated by a chemical remover of the endothelium (saponin at concentrations of 0.1 and 0.4 mg/mL) in a concentration-dependent manner (P < 0.05). 4. The cyclo-oxygenase (COX)-1 inhibitor flurbiprofen (0.01-1 micromol/L) and the COX-2 inhibitor nimesulide (0.01-1 micromol/L) attenuated the NA-induced contraction in a concentration-dependent manner and the inhibitory effect of flurbiprofen was significantly more potent than that of nimesulide (P < 0.05). The 5-lipoxigenase inhibitor ZM-230487 (1 micromol/L) did not affect the NA-induced contraction. 5. The thromboxane A2 (TXA2) synthetase inhibitor OKY-046 (30 micromol/L) and the TXA2 antagonist S-1452 (0.1-10 micromol/L) did not attenuate the NA-induced contraction. 6. These results indicate that the contraction induced by NA in the rat coronary artery in the presence of L-NAME and arachidonic acid is endothelium dependent and is due to endothelial COX metabolites of arachidonic acid.

The endocannabinoid arachidonyl ethanolamide (anandamide) increases pulmonary arterial pressure via cyclooxygenase-2 products in isolated rabbit lungs

Several cannabinoids elicit systemic vasodilation, mainly via CB1 cannabinoid and vanilloid receptors. However, effects in the pulmonary circulation are unknown. Using the isolated, ventilated, buffer-perfused rabbit lung, we have shown that the endocannabinoids arachidonyl ethanolamide (anandamide) and 2-arachidonyl glycerol (2-AG) dose-dependently increase pulmonary arterial pressure (+19.9 +/- 3.4 mmHg, 5 microM, and +39.5 +/- 10.8 mmHg, 0.4 microM, respectively). 2-AG induced lung edema. The CB1 receptor antagonist AM-251 (0.1 and 5 microM) and the VR1 vanilloid receptor antagonist capsazepine (10 microM) failed to reduce anandamide's effects. The metabolically stable anandamide and 2-AG analogs R-methanandamide and noladin ether, Delta9-tetrahydrocannabinol, and the synthetic cannabinoid HU-210, which is no arachidonic acid product, were without effect. The unspecific cyclooxygenase (COX) inhibitor aspirin (100 microM, P < 0.001) and the specific COX-2 inhibitor nimesulide (10 microM, P < 0.01) completely prevented pulmonary hypertension after 5 microM anandamide. COX-2 RNA was detected in rabbit lungs. The synthetic thromboxane receptor antagonist SQ 29,548 was without effect, but the specific EP1 prostanoid receptor antagonist SC-19220 (100 microM) inhibited the pressure increase after anandamide (P < 0.05). PCR analysis detected fatty acid amidohydrolase (FAAH), an enzyme that degrades endocannabinoids, in rabbit lung tissue. Furthermore, the specific FAAH inhibitor methyl arachidonyl fluorophosphonate (0.1 microM) blocked pressure effects of anandamide (P < 0.01). Finally, anandamide (99 +/- 55 pmol/g) and 2-AG (19.6 +/- 8.4 nmol/g) were found in native lungs. We conclude that anandamide increases pulmonary arterial pressure via COX-2 metabolites following enzymatic degradation by FAAH into arachidonic acid products.

Cyclooxygenase-2 Inhibitors Attenuate Angiotensin II–Induced Oxidative Stress, Hypertension, and Cardiac Hypertrophy in Rats

Angiotensin II is an important oxidative stress mediator. Our previous studies have indicated that the potent antioxidative properties of acetylsalicylic acid play an important role in its cardiovascular protective effects. There are some ongoing controversies concerning the use of selective cyclooxygenase-2 inhibitors in cardiovascular disease. The aim of this study was to determine whether the cyclooxygenase-2 selective inhibitors rofecoxib and nimesulide possess antioxidative and cardiovascular protective effects against angiotensin II. Chronic subcutaneous angiotensin II infusion increased cardiovascular but not colonic tissue superoxide production, heart/body weight ratio, and blood pressure. Moreover, angiotensin II selectively increased cardiac cyclooxygenase-2 but not cyclooxygenase-1 expression, which was totally prevented by acetylsalicylic acid treatment. Similar to acetylsalicylic acid, rofecoxib or nimesulide treatments significantly attenuated angiotensin II-induced oxidative stress, hypertension, and cardiac NAD(P)H oxidase subunit p47(phox) expression. Rofecoxib also reduced cardiac hypertrophy. Treatment with nonselective anti-inflammatory drugs ibuprofen, indomethacin, or salicylic acid did not show any effect on angiotensin II-induced superoxide production, hypertension, or cardiac hypertrophy. Although acetylsalicylic acid and salicylic acid inhibited angiotensin II-induced nuclear factor kappaB (NF-kappaB) activation, nimesulide did not modify NF-kappaB activation. In conclusion, cyclooxygenase-2 pathway is implicated in angiotensin II-induced oxidative stress and deleterious cardiovascular changes. Rofecoxib and nimesulide produced significant antioxidative effect by reducing NAD(P)H oxidase-dependent superoxide generation. These effects seem to be independent of NF-kappaB inhibition.