|Ki: ||Kd:||Ic 50:||Ec50/Ic50:|
Effect of COX-2 inhibitor NS-398 on expression of PGE2 receptor subtypes in M-1 mouse CCD cells.. R Nasrallah; O Laneuville; S Ferguson; R L Hébert (2001) American journal of physiology. Renal physiology display abstract
Our present study has investigated the effect of cyclooxygenase-2 (COX-2) inhibition on prostaglandin E2 (PGE2) receptor expression in M-1 cortical collecting duct cells and measured their response to PGE2. Using a semiquantitative titration analysis method, we show that following the addition of the COX-2-specific inhibitor NS-398, E-prostanoid receptor subtype (EP3 and EP4) mRNA expression was found to increase threefold each vs. the vehicle-treated control. We also observed that EP1 but not EP2 is expressed in M-1 cells and EP2 levels are not induced by NS-398. To determine the status of the PGE2 response on exposure to NS-398, we measured cAMP levels in cells after stimulation with varying concentrations of PGE2, then pretreated the cells with 10 microM NS-398 before PGE2 exposure and found a significant rise in the stimulatory effect of PGE2 on cAMP production. Finally, Western blot analysis of the levels of the EP4 receptor protein in control vs. NS-398-treated cells revealed an induction in protein levels in these cells, correlating with the induction in EP4 mRNA. We conclude that NS-398 upregulates the expression of EP3 and EP4 mRNA in M-1 cells. Also, EP4 protein levels are increased, resulting in an increased stimulation of cAMP production by PGE2.
Cyclooxygenase-2 inhibitor ns-398 protects neuronal cultures from lipopolysaccharide-induced neurotoxicity.. E Araki; C Forster; J M Dubinsky; M E Ross; C Iadecola (2001) Stroke; a journal of cerebral circulation display abstract
BACKGROUND AND PURPOSE: The prostanoid-synthesizing enzyme cyclooxygenase (COX)-2 is markedly upregulated after cerebral ischemia and may participate in the mechanisms by which postischemic inflammation contributes to the late stages of ischemic brain injury. In the present study, we sought to provide additional evidence for a role of COX-2 in the mechanisms of neurotoxicity associated with inflammation. METHODS: Nine-day-old neuronal-glial cultures, prepared from the cerebral cortex of newborn C57BL/6J mice, were exposed to lipopolysaccharide (LPS), a potent proinflammatory agent. The contribution of COX-2 was investigated by using the COX-2 inhibitor NS-398. RESULTS: LPS produced a dose-dependent (0.001 to 10 microg/mL) and selective neuronal death that was well developed 72 hours after treatment. The effect was associated with a marked increase in the concentration of the COX reaction product prostaglandin E(2) (PGE(2)) and of the cytokine tumor necrosis factor-alpha (TNF-alpha). NS-398 (10 micromol/L) blocked the PGE(2) increase, attenuated the TNF-alpha increase, and prevented the neuronal death produced by LPS. TNF-alpha-blocking antibodies attenuated LPS-induced neuronal death, but the protection was less pronounced than that afforded by NS-398. LPS failed to elevate PGE(2) or to produce cell death in neuron-enriched cultures, suggesting that glial cells are required for these effects. CONCLUSIONS: COX-2, in part through TNF-alpha-related mechanisms, contributes to LPS-induced neuronal death. The data support the hypothesis that COX-2, in addition to its role in glutamate excitotoxicity, participates in the cytotoxicity associated with inflammation.
Cyclooxygenase 2-mediated suppression of macrophage interleukin-12 production after thermal injury.. Martin G Schwacha; Chun-Shiang Chung; Alfred Ayala; Kirby I Bland; Irshad H Chaudry (2002) American journal of physiology. Cell physiology display abstract
Macrophage (Mphi) prostaglandin (PG)E(2) production has been implicated in immunosuppression and increased susceptibility to sepsis after thermal injury. Deficient interleukin (IL)-12 production has also been implicated in these postburn complications. The present study examined the relationship between Mphi cyclooxygenase (COX)-2 activity and IL-12 production after thermal injury. C57BL/6 female mice were subjected to a 25% total body surface area full-thickness burn. Mphi were isolated 7 days later, or the mice were subjected to sepsis by cecal ligation and puncture (CLP). IL-12 production by Mphi from injured mice was suppressed by >50%, whereas COX-2 expression and PGE(2) production were increased twofold. The COX-2 inhibitor NS-398 suppressed PGE(2) production and normalized IL-12 production in the injury group, whereas it had no effect on IL-10 production. Injured mice subjected to CLP had lower IL-12 plasma levels compared with sham-treated mice subjected to CLP. NS-398 treatment prevented the suppression in plasma IL-12 levels in the injury group. Thus elevated Mphi COX-2 activity, independent of IL-10, suppresses Mphi IL-12 production after thermal injury and may play an important role in the observed immunosuppression under such conditions.
NS-398 inhibits tumor growth and liver metastasis of colon cancer through induction of apoptosis and suppression of the plasminogen activation system in a mouse model.. Masayasu Nishikawa; Philip P Stapleton; Tracy A Freeman; John P Gaughan; Takeaki Matsuda; John M Daly (2004) Journal of the American College of Surgeons display abstract
BACKGROUND: Cyclooxygenase-2 (COX-2) is overexpressed in colon cancers. The plasminogen activation (PA) system relates to cancer invasion and metastasis through the degradation of the extracellular matrix. COX-2 also relates to degradation of the extracellular matrix, but the relationship between COX-2 and the plasminogen activator system is unclear. STUDY DESIGN: In vivo: Colon 38 (G0) primary and (G5) metastatic cell lines were implanted in C57BL/6 mice treated with or without COX-2 inhibitor (NS-398). Animal survival and tumor growth were measured. On day 19, tumors were excised and tumor cell apoptosis measured. For metastasis, G5 cells were injected into the spleen, and, after 23 days, liver metastasis was determined. In vitro: G0 or G5 cells were treated with NS-398. Supernatant prostaglandin E2 and mRNA expressions of COX-2, vascular endothelial growth factor (VEGF), urokinase-type plasminogen activator (u-PA), u-PA receptor, plasminogen activator inhibitor type-1 (PAI-1), and PAI-2 were measured. Tumor cell proliferation was also determined. RESULTS: In vivo: Mean survival of NS-398-treated animals was higher than controls for both G5 and G0 (G5: p < 0.003, G0: p < 0.02). G5 tumors grew faster than G0 tumors (p < 0.001) and NS-398 significantly inhibited tumor growth (p < 0.001), induced tumor cell apoptosis (p < 0.001), and significantly reduced metastasis (p < 0.003) in G5 animals. In vitro: PGE(2) production was higher in G5 than G0 cells (p < 0.001); NS-398 significantly reduced prostaglandin E(2) levels in G5 cells (p < 0.001). mRNA expression of COX-2, vascular endothelial growth factor, and u-PA receptor was higher in G5 than G0 cells, and NS-398 significantly inhibited u-PA mRNA expression in G5 cells. NS-398 significantly reduced proliferation in G5 cells (p < 0.05). CONCLUSIONS: COX-2 inhibition significantly decreases tumor growth in this model by inducing apoptosis and blocking u-PA production in G5 colon cancer cells, which is associated with significant inhibition of liver metastases.
Cyclooxygenase-2 inhibition suppresses alphavbeta6 integrin-dependent oral squamous carcinoma invasion.. Maria L Nystrom; Diana McCulloch; Paul H Weinreb; Shelia M Violette; Paul M Speight; John F Marshall; Ian R Hart; Gareth J Thomas (2006) Cancer research display abstract
Worldwide oral squamous cell carcinoma (OSCC) represents about 5.5% of all malignancies, with approximately 30,000 new cases each year in the United States. The integrin alpha(v)beta(6) and the enzyme cyclooxygenase-2 (COX-2) are implicated in OSCC progression and have been suggested as possible therapeutic targets. Each protein also is reported to identify dysplasias at high risk of malignant transformation, and current clinical trials are testing the efficacy of nonsteroidal anti-inflammatory drugs (NSAID) at preventing OSCC development. Given the probable increased expression of alpha(v)beta(6) and COX-2 in OSCC and the inhibition of several integrins by NSAIDs, we investigated whether NSAIDs affected alpha(v)beta(6)-dependent cell functions. We found that expression of both alpha(v)beta(6) and COX-2 was significantly higher in OSCC compared with oral epithelial dysplasias. Neither protein preferentially identified those dysplastic lesions that became malignant. Using OSCC cell lines, modified to express varying levels of alpha(v)beta(6), we assessed the effect of COX-2 inhibition on cell invasion. We found that the COX-2 inhibitor NS398 inhibited specifically alpha(v)beta(6)-dependent, but not alpha(v)beta(6)-independent, OSCC invasion in vitro and in vivo, and this effect was modulated through prostaglandin E(2) (PGE(2))-dependent activation of Rac-1. Transient expression of constitutively active Rac-1, or addition of the COX-2 metabolite PGE(2), prevented the anti-invasive effect of NS398. Conversely, RNA interference down-regulation of Rac-1 inhibited alpha(v)beta(6)-dependent invasion. These findings suggest that COX-2 and alpha(v)beta(6) interact in promoting OSCC invasion. This is a novel mechanism that, given the ubiquity of alpha(v)beta(6) expression by head and neck cancers, raises the possibility that NSAIDs could protect against OSCC invasion.