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Drugs that inhibit cyclooxygenase (COX)-2 and the metabolism of arachidonic acid (ARA) to prostaglandin E2 are potent anti-inflammatory agents used widely in the treatment of joint and muscle pain. Despite their benefits, daily use of these drugs has been associated with hypertension, cardiovascular and gastrointestinal toxicities. It is now recognized that ARA is metabolized to a number of bioactive oxygenated lipids (oxylipins) by cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP450) enzymes. Currently, the contribution of individual variability in ARA metabolism in response to the COX-2 inhibitors and potential adverse effects remains poorly understood. Using patient samples from the randomized, placebo-controlled phase III selenium/celecoxib (Sel/Cel) trial for the prevention of colorectal adenomatous polyps, we analyzed plasma concentrations of 74 oxylipins in a subset of participants who received celecoxib (n = 90) or placebo (n = 95). We assessed the effect of celecoxib (with and without low dose aspirin) on circulating oxylipins and systolic blood pressure (SBP). Individual CYP450- and LOX- but not COX-derived metabolites were higher with celecoxib than placebo (P

Celecoxib (CLB) is a highly hydrophobic selective cyclo-oxygenase inhibitor with high plasma protein binding and undergoes extensive hepatic metabolism. CLB is highly effective in the treatment of osteo and rheumatoid arthritis as first line therapy but produces severe gastro-intestinal toxicities and cardiovascular side effects. In this research, stealth liposomes of CLB were developed with the intention to reduce the side effects and increase the accumulation of drug in the sites of inflammation. Stealth liposomes were prepared by thin film hydration technique using distearoylphosphatidylcholine and PE-PEG 2000 with variable amounts of cholesterol and characterized. The effects of various lipids such as hydrogenated soy phosphatidylcholine, dipalmitoyl phosphatidylcholine, distearoylphosphatidylcholine and cholesterol content on % drug encapsulation was investigated. The optimized stealth liposomes were characterized by FT-IR and DSC for possible drug excipients interaction. Pharmacokinetics, pharmacodynamics and biodistribution studies were carried out for the stealth liposomes. The results revealed that the stealth liposomes reduced the inflammation to the larger magnitude and have also sustained the magnitude when compared to free drug along with maximum analgesic response. Higher elimination half-life, AUC, MRT and lowered clearance rate denotes the extended bioavailability of the drug in blood. Biodistribution studies revealed that stealth liposomes extend the circulation time of liposomes in blood by decreasing opsonisation and be less concentrated in kidney, thereby reducing the toxicities to RES and renal organs and facilitate the drug accumulation in the area of inflammation. Our results indicated that CLB, without the requirement of modifications to enhance solubilisation, can be encapsulated and released from liposomal formulations. This new-fangled drug delivery approach may be used to circumvent the low bioavailability and toxic side effects of oral CLB formulations. [ABSTRACT FROM AUTHOR]

Objective: To assess the cardiovascular safety of celecoxib compared to non-selective non-steroid anti-inflammatory drugs or placebo. Methods: We included randomized controlled trials of oral celecoxib compared with a non-selective NSAID or placebo in rheumatoid arthritis and osteoarthritis patients. We conducted searches in EMBASE, Cochrane CENTRAL, MEDLINE, China National Knowledge Infrastructure, VIP, Wanfang, and Chinese Biomedical Literature Database. Study selection and data extraction were done by two authors independently. The risk of bias was assessed using Cochrane's risk-of-bias Tool for Randomized Trials. The effect size was presented as a risk ratio with their 95% confidence interval. Results: Until July 22nd, 2021, our search identified 6279 records from which, after exclusions, 21 trials were included in the meta-analysis. The overall pooled risk ratio for Antiplatelet Trialists Collaboration cardiovascular events for celecoxib compared with any non-selective non-steroid anti-inflammatory drugs was 0.89 (95% confidence interval: 0.80–1.00). The pooled risk ratio for all-cause mortality for celecoxib compared with non-selective non-steroid anti-inflammatory drugs was 0.81 (95% confidence interval: 0.66–0.98). The cardiovascular mortality rate of celecoxib was lower than non-selective non-steroid anti-inflammatory drugs (risk ratio: 0.75, 95% confidence interval: 0.57–0.99). There was no significant difference between celecoxib and non-selective non-steroid anti-inflammatory drugs or placebo in the risk of other cardiovascular events. Conclusion: Celecoxib is relatively safe in rheumatoid arthritis and osteoarthritis patients, independent of dose or duration. But it remains uncertain whether this would remain the same in patients treated with aspirin and patients with established cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Hyperlipidaemia is a major risk factor for cardiovascular diseases, the leading cause of death globally. Celecoxib attenuated hypercholesterolaemia associated with CCl4-induced hepatic injury in rats without improving liver function in our previous study. This present study investigated the lipid lowering potential of celecoxib in normal rats fed with coconut oil subjected to five deep-frying episodes. Male Sprague Dawley rats were randomly assigned to groups (n = 6 rats/group) which received physiological saline (10 mL/kg), unheated coconut oil (UO, 10 mL/kg) or heated coconut oil (HO, 10 ml/kg) for 60 days. Groups that received HO were subsequently treated with either physiological saline, atorvastatin (25 mg/kg), celecoxib (5 mg/kg) or celecoxib (10 mg/kg) in the last fifteen days of the experiment. Rats were sacrificed 24 hours after last treatment and blood and tissue samples collected for analysis. HO consumption produced significant hyperlipidaemia and elevation in marker enzymes of hepatic function. Celecoxib ameliorated the hyperlipidaemia as shown by the significantly (P<0.05) lower total cholesterol, triglycerides, low and very low density lipoprotein in the celecoxib-treated rats when compared with HO-fed rats that received saline. Celecoxib also reduced (P<0.05) alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and liver weight of hyperlipidaemic rats. Similarly, hepatocellular damage with the hyperlipidaemia was significantly reversed by celecoxib. However, serum TNF-α and IL-6 did not change significantly between the various groups. Taken together, data from this study suggest that celecoxib may exert therapeutic benefit in hyperlipidaemia and its attendant consequences. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to examine the cost-effectiveness of branded and authorized generic (AG) celecoxib for chronic pain patients with osteoarthritis (OA), rheumatoid arthritis (RA), and low back pain (LBP), using real-world cost information for loxoprofen and pharmacotherapy for gastrointestinal bleeding. Methods: This cost-effectiveness analysis was performed as a long-term simulation using the Markov model from the Japanese public healthcare payer's perspective. The analysis was conducted using loxoprofen with real-world weighted price by branded/generic distribution (hereinafter, loxoprofen with weighted price) as a comparator. In the model, we simulated the prognosis of patients with chronic pain by OA, RA, and LBP treated with loxoprofen or celecoxib, over a lifetime period. Results: A cost-increase of 129,688 JPY (1,245.00 USD) for branded celecoxib and a cost-reduction of 6,268 JPY (60.17 USD) for AG celecoxib were recognized per patient in lifetime horizon, compared to loxoprofen with weighted price. No case was recognized to reverse the results of cost-saving by AG celecoxib in one-way sensitivity analysis. The incremental cost-effectiveness ratio of branded celecoxib attained 5,403,667 JPY/QALY (51,875.20 USD/QALY), compared to loxoprofen with the weighted price. Conclusion: The current cost-effectiveness analysis for AG celecoxib revealed its good value for costs, considering the patients' future risk of gastrointestinal injury; also, the impact on costs due to AG celecoxib against loxoprofen will be small. It implies that the disadvantage of AG celecoxib being slightly more expensive than generic loxoprofen could be offset by the good cost-effectiveness during the prognosis. [ABSTRACT FROM AUTHOR]

Objective: Selective cyclooxygenase-2 inhibitors (celecoxib) can minimize the gastrointestinal complications related to non-steroidal anti-inflammatory drug (NSAID) use. NAXOZOL is a new combination formulation designed to provide sequential delivery of a non-enteric-coated, immediate-release esomeprazole strontium tetrahydrate 20 mg mantle followed by an enteric-coated naproxen 500 mg core. However, there have been no studies comparing NAXOZOL to celecoxib with respect to gastrointestinal tract protection and pain relief in patients with osteoarthritis. This study was undertaken to compare the effects of NAXOZOL and celecoxib with respect to gastrointestinal tract protection and pain relief in patients with osteoarthritis. Methods: The randomized enrolled patients were divided into two treatment groups: a NAXOZOL group and a celecoxib group. All participants received treatments (NAXOZOL, 500/20 mg (naproxen 500 mg, esomeprazole strontium tetrahydrate 20 mg) twice per day versus celecoxib, 200 mg daily) on a 1:1 allocation basis for 12 weeks. The primary outcome was the Leeds Dyspepsia Questionnaire (LDQ) score used for non-inferiority testing. Secondary outcome measures included the Gastrointestinal Symptom Rating Scale (GSRS) score, Visual Analogue Scale (VAS) score, European Quality of Life-5 dimensions (EQ-5D) scale and the EQ-5D Visual Analogue Scale (EQ VAS). Other outcome measures included the use of supplementary or rescue drugs, and the incidence of adverse events. Results: The baseline-adjusted LDQ scores immediately after 12 weeks of treatment in NAXOZOL group were not inferior to those in celecoxib group. The overall change in the baseline-adjusted GSRS score, VAS score, EQ-5D, and EQ VAS was not different between the two groups. The usage of supplementary drugs and the drug-related incidence of adverse events were not different. However, the days to use rescue drug were longer in celecoxib group than in NAXOZOL group. Conclusion: NAXOZOL was not inferior to celecoxib in protecting the gastrointestinal tract and providing pain relief in patients with osteoarthritis. [ABSTRACT FROM AUTHOR]

The current study aimed to identify the radiosensitizing effect of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, in combination with radiotherapy in non-small-cell lung cancer (NSCLC) cells. The combination of celecoxib potentiated radiation-induced apoptosis; however, no changes in cell cycle distribution and number of phosphorylated histone H2AX foci were detected, indicating a DNA damage-independent mechanism. In an in vivo mouse model, the tumor size was significantly decreased in the group combining celecoxib with radiation compared with the radiation only group. Phosphorylation of protein kinase B (Akt) and mammalian target of rapamycin (mTOR), as well as expression of COX-2 were significantly downregulated in cells treated with the combination of celecoxib and radiation compared with the radiation only group. The result indicated that celecoxib exhibits radiosensitizing effects through COX-2 and Akt/mTOR-dependent mechanisms. Induction the Akt/mTOR signaling pathway promotes radioresistance in various cancers, including NSCLC. Therefore, the current study suggested the therapeutic potential of combination therapy of celecoxib and radiation in the prevention of radioresistance. [ABSTRACT FROM AUTHOR]

Recently, the United States Food and Drug Administration approved a new oral dosage preparation of amlodipine besylate (AML) and celecoxib (CEL) for the management of hypertension and osteoarthritis. However, no simultaneous estimation procedures for these two analytes have been described. Hence, two simple, accurate, and precise ultraviolet spectroscopic procedures that manipulated the ratio spectra were established for concurrent quantification of AML and CEL using ethanol as a solvent. The first method involves determining the peak-to-trough amplitude difference of the ratio spectra of AML and CEL. The second method involves determining the peak amplitude of the ratio first derivative (Δλ 4 nm) spectra of AML and CEL at 334.2 nm and 254.2 nm, correspondingly. Both methods showed linearity in the range of 1–6 μg mL-1 for AML and 5–40 μg mL-1 for CEL with an excellent correlation coefficient (<0.999). The proposed procedures were validated by following the International Conference on Harmonization guidelines for accuracy, precision, selectivity, recovery, and stability studies. It is evident from the low %RSD and %RE that both analytical procedures were found to be accurate and precise, respectively. The percent recovery of AML and CEL from the formulation was found to be 99.79% and 99.34% using the ratio-difference method and 100.13% and 99.70% using the ratio first-derivative method, with a low percent relative standard deviation. Further, the proposed techniques permit concurrent quantification of AML and CEL in different concentration ratios without interference from each other; hence, these techniques can be adopted for regular quality-control studies. [ABSTRACT FROM AUTHOR]

Objective: Hepatopulmonary syndrome (HPS) is characterized by hypoxia in patients with chronic liver disease. The mechanism of HPS includes pulmonary vasodilatation, inflammation, and angiogenesis. Prostaglandins synthesized by cyclooxygenases (COX) participate in vascular responsiveness, inflammation and angiogenesis, which can be modulated by COX inhibitors. We therefore evaluated the impact of COX inhibition in rats with common bile duct ligation (CBDL)-induced liver cirrhosis and HPS. Methods: Cirrhotic rats were randomly allocated to receive non-selective COX inhibitor (indomethacin), selective COX-1 inhibitor (SC-560), or COX-2 inhibitor (celecoxib) for 14 days. After that, hemodynamic parameters, severity of hypoxia and intrapulmonary shunts, liver and renal biochemistry parameters, histological finding and protein expressions were evaluated. Results: Non-selective COX inhibition by indomethacin improved hepatic fibrosis and pulmonary inflammation in cirrhotic rats with HPS. It also decreased mean arterial blood pressure, portal pressure, and alleviated hypoxia and intrapulmonary shunts. However, indomethacin increased mortality rate. In contrast, selective COX inhibitors neither affected hemodynamics nor increased mortality rate. Hypoxia was improved by SC-560 and celecoxib. In addition, SC-560 decreased intrapulmonary shunts, attenuated pulmonary inflammation and angiogenesis through down-regulating COX-, NFκB- and VEGF-mediated pathways. Conclusion: Selective COX-1 inhibitor ameliorated HPS by mitigating hypoxia and intrapulmonary shunts, which are related to anti-inflammation and anti-angiogenesis. [ABSTRACT FROM AUTHOR]

Polymer based nanoparticle formulations have been shown to increase drug bioavailability and/or reduce drug adverse effects. Nonsteroidal anti-inflammatory drugs (e.g. celecoxib) reduce prostaglandin synthesis and cause side effects such as gastrointestinal and renal complications. The aim of this study was to formulate celecoxib entrapped poly lactide-co-glycolide based nanoparticles through a solvent evaporation process using didodecyldimethylammonium bromide or poly vinyl alcohol as stabilizer. Nanoparticles were characterized for zeta potential, particle size, entrapment efficiency, and morphology. Effects of stabilizer concentration (0.1, 0.25, 0.5, and 1% w/v), drug amount (5, 10, 15, and 20 mg), and emulsifier (lecithin) on nanoparticle characterization were examined for formula optimization. The use of 0.1, 0.25, and 0.5% w/v didodecyldimethylammonium bromide resulted in a more than 5-fold increase in zeta potential and a more than 1.5-fold increase in entrapment efficiency with a reduction in particle size over 35%, when compared to stabilizer free formulation. Nanoparticle formulations were also highly influenced by emulsifier and drug amount. Using 0.25% w/v didodecyldimethylammonium bromide NP formulations, peak zeta potential was achieved using 15 mg celecoxib with emulsifier (17.15±0.36 mV) and 20 mg celecoxib without emulsifier (25.00±0.18 mV). Peak NP size reduction and entrapment efficiency was achieved using 5 mg celecoxib formulations with (70.87±1.24 nm and 95.55±0.66%, respectively) and without (92.97±0.51 nm and 95.93±0.27%, respectively) emulsifier. In conclusion, formulations using 5 mg celecoxib with 0.25% w/v didodecyldimethylammonium bromide concentrations produced nanoparticles exhibiting enhanced size reduction and entrapment efficiency. Furthermore, emulsifier free formulations demonstrated improved zeta potential when compared to formulations containing emulsifier (p<0.01). Therefore, our results suggest the use of emulsifier free 5 mg celecoxib drug formulations containing 0.25% w/v didodecyldimethylammonium bromide for production of polymeric NPs that demonstrate enhanced zeta potential, small particle size, and high entrapment efficiency. [ABSTRACT FROM AUTHOR]

Dimethyl-celecoxib is a celecoxib analog that lacks the capacity as cyclo-oxygenase-2 inhibitor and therefore the life-threatening effects but retains the antineoplastic properties. The action mechanism at the molecular level is unclear. Our in vitro assays using a sarcoplasmic reticulum preparation from rabbit skeletal muscle demonstrate that dimethyl-celecoxib inhibits Ca2+-ATPase activity and ATP-dependent Ca2+ transport in a concentration-dependent manner. Celecoxib was a more potent inhibitor of Ca2+-ATPase activity than dimethyl-celecoxib, as deduced from the half-maximum effect but dimethyl-celecoxib exhibited higher inhibition potency when Ca2+ transport was evaluated. Since Ca2+ transport was more sensitive to inhibition than Ca2+-ATPase activity the drugs under study caused Ca2+/Pi uncoupling. Dimethyl-celecoxib provoked greater uncoupling and the effect was dependent on drug concentration but independent of Ca2+-pump functioning. Dimethyl-celecoxib prevented Ca2+ binding by stabilizing the inactive Ca2+-free conformation of the pump. The effect on the kinetics of phosphoenzyme accumulation and the dependence of the phosphoenzyme level on dimethyl-celecoxib concentration were independent of whether or not the Ca2+–pump was exposed to the drug in the presence of Ca2+ before phosphorylation. This provided evidence of non-preferential interaction with the Ca2+-free conformation. Likewise, the decreased phosphoenzyme level in the presence of dimethyl-celecoxib that was partially relieved by increasing Ca2+ was consistent with the mentioned effect on Ca2+ binding. The kinetics of phosphoenzyme decomposition under turnover conditions was not altered by dimethyl-celecoxib. The dual effect of the drug involves Ca2+-pump inhibition and membrane permeabilization activity. The reported data can explain the cytotoxic and anti-proliferative effects that have been attributed to the celecoxib analog. Ligand docking simulation predicts interaction of celecoxib and dimethyl-celecoxib with the intracellular Ca2+ transporter at the inhibition site of hydroquinones. [ABSTRACT FROM AUTHOR]

DAF-16 target genes are employed as reporters of the insulin/IGF-1 like signal pathway (IIS), and this is notably true when Caenorhabditis elegans (C. elegans) is used to study the action of anti-aging compounds on IIS activity. However, some of these genes may not be specific to DAF-16, even if their expression levels are altered when DAF-16 is activated. Celecoxib was reported to extend the lifespan of C. elegans through activation of DAF-16. Our results confirmed the function of celecoxib on aging; however, we found that the expression of ins-7, a DAF-16 target gene, was abnormally regulated by celecoxib. ins-7 plays an important role in regulating aging, and its expression is suppressed in C. elegans when DAF-16 is activated. However, we found that celecoxib upregulated the expression of ins-7 in contrast to its role in DAF-16 activation. Our subsequent analysis indicated that the expression level of ins-7 in C. elegans was negatively regulated by DAF-16 activity. Additionally, its expression was also positively regulated by DAF-16-independent mechanisms, at least following external pharmacological intervention. Our study suggests that ins-7 is not a specific target gene of DAF-16, and should not be chosen as a reporter for IIS activity. This conclusion is important in the study of INSs on aging in C. elegans, especially under the circumstance of drug intervention. [ABSTRACT FROM AUTHOR]

We have previously shown that celecoxib in combination with an antibiotic, increase the bacterial sensitivity to antibiotics. However, the underlying molecular mechanism remained elusive. Efficacy of the combinatorial treatment of celecoxib and ampicillin in vitro was evaluated on macrophage-phagocytosed S aureus. To elucidate the mechanism, signaling pathway of infection and inflammation involving TLR2, JNK, SIRT1 and NF-κB was studied by FACS, Western blot, ELISA and activity assays. Combinatorial treatment of ampicillin and celecoxib reduced the bacterial load in the macrophages. Further studies clearly suggested the activation of the master regulator of oxidative stress and inflammation SIRT1,, by celecoxib when used alone and/or in combination with ampicillin. Also, the results indicated that celecoxib inhibited JNK phosphorylation thereby stabilizing and activating SIRT1 protein that inhibited the COX-2 gene transcription with a significant decrease in the levels of protein inflammatory cytokines like IL-6, MIP-1α and IL-1β via inhibition of NF-κB. SIRT1 activation by celecoxib also resulted in increase of catalase and peroxidase activity with a decrease in Nitric oxide levels. In conclusion, we demonstrate a novel role of celecoxib in controlling inflammation as an enhancer of antibiotic activity against bacteria by modulating SIRT1. [ABSTRACT FROM AUTHOR]

Nonsteroidal anti-inflammatory drugs (NSAIDs) can produce adverse effects by inhibiting prostaglandin (PG) synthesis. A PGE1 analogue, misoprostol, is often utilized to alleviate NSAID-related gastrointestinal side effects. This study examined the effect of misoprostol on celecoxib renal toxicity. Additionally, the effects of these drugs on cardiovascular parameters were evaluated. Four randomized rat groups were orally gavaged for 9 days, two groups receiving vehicle and two groups receiving misoprostol (100 µg/kg) twice daily. Celecoxib (40 mg/kg) was co-administered once daily to one vehicle and one misoprostol group from days 3 to 9. Urine and blood samples were collected and blood pressure parameters were measured during the study period. Hearts and kidneys were harvested on final day. Day 2 urinary electrolyte samples revealed significant reductions in sodium excretion in misoprostol (0.12±0.05 µmol/min/100 g) and misoprostol+celecoxib groups (0.07±0.02 µmol/min/100 g). At day 3, all treatment groups showed significantly reduced sodium excretion. Potassium excretion diminished significantly in vehicle+celecoxib and misoprostol+celecoxib groups from day 3 onward. Urinary kidney injury molecule-1 levels were significantly increased in vehicle+celecoxib (0.65±0.02 vs. 0.35±0.07 ng/mL, p = 0.0002) and misoprostol+celecoxib (0.61±0.06 vs. 0.37±0.06 ng/mL, p = 0.0015) groups when compared to baseline; while plasma levels of cardiac troponin I increased significantly in vehicle+celecoxib (p = 0.0040) and misoprostol+misoprostol (p = 0.0078) groups when compared to vehicle+vehicle. Blood pressure parameters increased significantly in all misoprostol treated groups. Significant elevation in diastolic (p = 0.0071) and mean blood pressure (p = 0.0153) was noted in misoprostol+celecoxib compared to vehicle+celecoxib. All treatments produced significant tubular dilatation/necrosis compared to control. No significant myocardial changes were noticed; however, three animals presented with pericarditis. Kidney, heart, and plasma celecoxib levels revealed no significant change between vehicle+celecoxib and misoprostol+celecoxib. Concomitant misoprostol administration did not prevent celecoxib renal toxicity, and instead exacerbated renal side effects. Misoprostol did not alter plasma or tissue celecoxib concentrations suggesting no pharmacokinetic interaction between celecoxib and misoprostol. [ABSTRACT FROM AUTHOR]

Our aim was to test whether pharmacological inhibition of cycloxygenase-2 (COX-2) reverses non-alcoholic steatohepatitis (NASH) in type 2 diabetes mellitus (T2DM) rats via suppression of the non-canonical Wnt signaling pathway expression. Twenty-four male Sprague-Dawley rats were randomly distributed to two groups and were fed with a high fat and sucrose (HF-HS) diet or a normal chow diet, respectively. After four weeks, rats fed with a HF-HS diet were made diabetic with low-dose streptozotocin. At the 9th week the diabetic rats fed with a HF-HS diet or the non-diabetic rats fed with a normal chow diet were further divided into two subgroups treated with vehicle or celecoxib (a selective COX-2 inhibitor, 10 mg/Kg/day, gavage) for the last 4 weeks, respectively. At the end of the 12th week, rats were anesthetized. NASH was assessed by histology. Related cytokine expression was measured at both the protein and gene levels through immunohistochemistry (IHC), Western blot and real-time PCR. T2DM rats fed with a HF-HS diet developed steatohepatitis and insulin resistance associated with elevated serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), insulin levels and the non-alcoholic fatty liver disease (NAFLD) activity score (NAS). The expression of Wnt5a, JNK1, NF-κB p65, and COX-2 were all significantly increased in the T2DM-NASH group compared with the control and control-cele group. Hepatic injury was improved by celecoxib in T2DM-NASH-Cele group indicated by reduced serum ALT and AST levels and hepatic inflammation was reduced by celecoxib showed by histology and the NAFLD activity score (NAS). Serum related metabolic parameters, HOMA-IR and insulin sensitivity index were all improved by celecoxib. The expression of Wnt5a, JNK1, NF-κB p65, and COX-2 expression were all suppressed by celecoxib in T2DM-NASH-Cele group. The results of the present study indicated that celecoxib ameliorated NASH in T2DM rats via suppression of the non-canonical Wnt5a/JNK1 signaling pathway expression. [ABSTRACT FROM AUTHOR]

Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, can elicit anti-tumor effects in various malignancies. Here, we sought to clarify the role of autophagy in celecoxib-induced cytotoxicity in human urothelial carcinoma (UC) cells. The results shows celecoxib induced cellular stress response such as endoplasmic reticulum (ER) stress, phosopho-SAPK/JNK, and phosopho-c-Jun as well as autophagosome formation in UC cells. Inhibition of autophagy by 3-methyladenine (3-MA), bafilomycin A1 or ATG7 knockdown potentiated celecoxib-induced apoptosis. Up-regulation of autophagy by rapamycin or GFP-LC3B-transfection alleviated celecoxib-induced cytotoxicity in UC cells. Taken together, the inhibition of autophagy enhances therapeutic efficacy of celecoxib in UC cells, suggesting a novel therapeutic strategy against UC. [ABSTRACT FROM AUTHOR]

Cholangiocarcinoma (CCA), a lethal disease, affects many thousands worldwide yearly. Surgical resection provides the best chance for a cure; however, only one-third of CCA patients present with a resectable tumour at the time of diagnosis. Currently, no effective chemotherapy is available for advanced CCA. Cyclooxygenase-2 (COX-2) is a potential oncogene expressing in human CCA tissues and represents a candidate target for treatment; however, COX-2 inhibitors increase the risk of negative cardiovascular events as application for chemoprevention aim. Here, we re-evaluated the effectiveness and safety of celecoxib, one widely used COX-2 inhibitor, in treating CCA. We demonstrated that celecoxib exhibited an anti-proliferative effect on CGCCA cells via cell cycle arrest at G2 phase and apoptosis induction. Treatment for 5 weeks high dose celecoxib (160 mg/kg) significantly repressed thioacetamide-induced CCA tumour growth in rats as monitored by animal positron emission tomography through apoptosis induction. No obviously observable side effects were noted during the therapeutic period. As retrospectively reviewing 78 intrahepatic mass-forming CCA patients, their survival was strongly and negatively associated with a positive resection margin and high COX-2 expression. Based on our result, we concluded that short-term high dose celecoxib may be a promising therapeutic regimen for CCA. Yet its clinical application still needs more studies to prove its safety. [ABSTRACT FROM AUTHOR]

Background: Increased intra-hepatic resistance to portal blood flow is the primary factor leading to portal hypertension in cirrhosis. Up-regulated expression of cyclooxygenase-2 (COX-2) in the cirrhotic liver might be a potential target to ameliorate portal hypertension. Objective: To verify the effect of celecoxib, a selective inhibitor of COX-2, on portal hypertension and the mechanisms behind it. Methods: Cirrhotic liver model of rat was established by peritoneal injection of thiacetamide (TAA). 36 rats were randomly assigned to control, TAA and TAA+celecoxib groups. Portal pressures were measured by introduction of catheters into portal vein. Hepatic fibrosis was assessed by the visible hepatic fibrotic areas and mRNAs for collagen III and α-SMA. The neovasculature was determined by hepatic vascular areas, vascular casts and CD31 expression. Expressions of COX-2, vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR-2) and related signal molecules were quantitated. Results: Compared with TAA group, the portal pressure in TAA+celecoxib group was significantly decreased by 17.8%, p<0.01. Celecoxib treatment greatly reduced the tortuous hepatic portal venules. The data of fibrotic areas, CD31expression, mRNA levels of α-SMA and collagen III in TAA+celecoxib group were much lower than those in TAA group, p<0.01. Furthermore, the up-regulation of hepatic mRNA and protein levels of VEGF, VEGFR-2 and COX-2 induced by TAA was significantly inhibited after celecoxib treatment. The expressions of prostaglandin E2 (PGE2), phosphorylated extracellular signal-regulated kinase (p-ERK), hypoxia-inducible factor-1α (HIF-1α), and c-fos were also down-regulated after celecoxib treatment. Conclusions: Long term administration of celecoxib can efficiently ameliorate portal hypertension in TAA rat model by its dual inhibitory effects on the intrahepatic fibrosis and angiogenesis. The anti-angiogenesis effect afforded by celecoxib may attribute to its modulation on VEGF/VEGFR-2 through the down-regulation of integrated signal pathways involving PGE2- HIF-1α- VEGF and p-ERK- c-fos- VEGFR-2. [ABSTRACT FROM AUTHOR]

Molecular targeted therapy has shown promise as a treatment for advanced hepatocellular carcinoma (HCC). Sorafenib, a multikinase inhibitor, recently received FDA approval for the treatment of advanced HCC. However, although sorafenib is well tolerated, concern for its safety has been expressed. Celecoxib (Celebrex®) is a selective cyclooxygenase-2 (COX-2) inhibitor which exhibits antitumor effects in human HCC cells. The present study examined the interaction between celecoxib and sorafenib in two human liver tumor cell lines HepG2 and Huh7. Our data showed that each inhibitor alone reduced cell growth and the combination of celecoxib with sorafenib synergistically inhibited cell growth and increased apoptosis. To better understand the molecular mechanisms underlying the synergistic antitumor activity of the combination, we investigated the expression profile of the combination-treated liver cancer cell lines using microarray analysis. Combination treatment significantly altered expression levels of 1,986 and 2,483 transcripts in HepG2 and Huh7 cells, respectively. Genes functionally involved in cell death, signal transduction and regulation of transcription were predominantly up-regulated, while genes implicated in metabolism, cell-cycle control and DNA replication and repair were mainly down-regulated upon treatment. However, combination-treated HCC cell lines displayed specificity in the expression and activity of crucial factors involved in hepatocarcinogenesis. The altered expression of some of these genes was confirmed by semi-quantitative and quantitative RT-PCR and by Western blotting. Many novel genes emerged from our transcriptomic analyses, and further functional analyses may determine whether these genes can serve as potential molecular targets for more effective anti-HCC strategies. [ABSTRACT FROM AUTHOR]

Cylcooxgenase-2 (COX-2) expressing macrophages, constituting a major portion of tumor mass, are involved in several pro-tumorigenic mechanisms. In addition, macrophages are actively recruited by the tumor and represent a viable target for anticancer therapy. COX-2 specific inhibitor, celecoxib, apart from its anticancer properties was shown to switch macrophage phenotype from tumor promoting to tumor suppressing. Celecoxib has low aqueous solubility, which may limit its tumor inhibiting effect. As opposed to oral administration, we propose that maximum anticancer effect may be achieved by nanoemulsion mediated intravenous delivery. Here we report multifunctional celecoxib nanoemulsions that can be imaged by both near-infrared fluorescence (NIRF) and 19F magnetic resonance. Celecoxib loaded nanoemulsions showed a dose dependent uptake in mouse macrophages as measured by 19F NMR and NIRF signal intensities of labeled cells. Dramatic inhibition of intracellular COX-2 enzyme was observed in activated macrophages upon nanoemulsion uptake. COX-2 enzyme inhibition was statistically equivalent between free drug and drug loaded nanoemulsion. However, nanoemulsion mediated drug delivery may be advantageous, helping to avoid systemic exposure to celecoxib and related side effects. Dual molecular imaging signatures of the presented nanoemulsions allow for future in vivo monitoring of the labeled macrophages and may help in examining the role of macrophage COX-2 inhibition in inflammation-cancer interactions. These features strongly support the future use of the presented nanoemulsions as anti-COX-2 theranostic nanomedicine with possible anticancer applications. [ABSTRACT FROM AUTHOR]

Background and Purpose: Celecoxib (CXB) is a widely prescribed COX-2 inhibitor used clinically to treat pain and inflammation. Recently, COX-2 independent mechanisms have been described to be the targets of CXB. For instance, ion channels such as the voltage-gated sodium channel, L-type calcium channel, Kv2.1, Kv1.5, Kv4.3 and HERG potassium channel were all reported to be inhibited by CXB. Our recent study revealed that CXB is a potent activator of Kv7/M channels. M currents expressed in dorsal root ganglia play an important role in nociception. Our study was aimed at establishing the role of COX-2 independent M current activation in the analgesic action of CXB. Methods and Results: We compared the effects of CXB and its two structural analogues, unmethylated CXB (UMC) and 2,5dimethyl-CXB (DMC), on Kv7/M currents and pain behavior in animal models. UMC is a more potent inhibitor of COX-2 than CXB while DMC has no COX-2 inhibiting activity. We found that CXB, UMC and DMC concentration-dependently activated Kv7.2/7.3 channels expressed in HEK293 cells and the M-type current in dorsal root ganglia neurons, negatively shifted I-V curve of Kv7.2/7.3 channels, with a potency and efficiency inverse to their COX-2 inhibitory potential. Furthermore, CXB, UMC and DMC greatly reduced inflammatory pain behavior induced by bradykinin, mechanical pain behavior induced by stimulation with von Frey filaments and thermal pain behavior in the Hargreaves test. CXB and DMC also significantly attenuated hyperalgesia in chronic constriction injury neuropathic pain. Conclusion: CXB, DMC and UMC are openers of Kv7/M K+ channels with effects independent of COX-2 inhibition. The analgesic effects of CXBs on pain behaviors, especially those of DMC, suggest that activation of Kv7/M K+ channels may play an important role in the analgesic action of CXB. This study strengthens the notion that Kv7/M K+ channels are a potential target for pain treatment. [ABSTRACT FROM AUTHOR]

Abdominal aortic aneurysms (AAAs) are a chronic inflammatory disease that increase the risk of life-threatening aortic rupture. In humans, AAAs have been characterized by increased expression of cyclooxygenase-2 and the inactivation of COX-2 prior to disease initiation reduces AAA incidence in a mouse model of the disease. The current study examined the effectiveness of selective cyclooxygenase-2 (COX-2) inhibition on reducing AAA progression when administered after the initiation of AAA formation. AAAs were induced in hyperlipidemic apolipoprotein E-deficient mice by chronic angiotensin II (AngII) infusion and the effect of treatment with the COX-2 inhibitor celecoxib was examined when initiated at different stages of the disease. Celecoxib treatment that was started 1 week after initiating AngII infusion reduced AAA incidence by 61% and significantly decreased AAA severity. Mice treated with celecoxib also showed significantly reduced aortic rupture and mortality. Treatment with celecoxib that was started at a late stage of AAA development also significantly reduced AAA incidence and severity. Celecoxib treatment significantly increased smooth muscle alpha-actin expression in the abdominal aorta and did not reduce expression of markers of macrophage-dependent inflammation. These findings indicate that COX-2 inhibitor treatment initiated after formation of AngII-induced AAAs effectively reduces progression of the disease in hyperlipidemic mice. [ABSTRACT FROM AUTHOR]

Celecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor that has been reported to elicit anti-proliferative response in various tumors. In this study, we aim to investigate the antitumor effect of celecoxib on urothelial carcinoma (UC) cells and the role endoplasmic reticulum (ER) stress plays in celecoxib-induced cytotoxicity. The cytotoxic effects were measured by MTT assay and flow cytometry. The cell cycle progression and ER stress-associated molecules were examined by Western blot and flow cytometry. Moreover, the cytotoxic effects of celecoxib combined with glucose-regulated protein (GRP) 78 knockdown (siRNA), (2)-epigallocatechin gallate (EGCG) or MG132 were assessed. We demonstrated that celecoxib markedly reduces the cell viability and causes apoptosis in human UC cells through cell cycle G1 arrest. Celecoxib possessed the ability to activate ER stress-related chaperones (IRE-1a and GRP78), caspase-4, and CCAAT/enhancer binding protein homologous protein (CHOP), which were involved in UC cell apoptosis. Down-regulation of GRP78 by siRNA, co-treatment with EGCG (a GRP78 inhibitor) or with MG132 (a proteasome inhibitor) could enhance celecoxib-induced apoptosis. We concluded that celecoxib induces cell cycle G1 arrest, ER stress, and eventually apoptosis in human UC cells. The downregulation of ER chaperone GRP78 by siRNA, EGCG, or proteosome inhibitor potentiated the cytotoxicity of celecoxib in UC cells. These findings provide a new treatment strategy against UC. [ABSTRACT FROM AUTHOR]

Background: Celecoxib (Celebrex), a widely prescribed selective inhibitor of cyclooxygenase-2, can modulate ion channels independently of cyclooxygenase inhibition. Clinically relevant concentrations of celecoxib can affect ionic currents and alter functioning of neurons and myocytes. In particular, inhibition of Kv2.1 channels by celecoxib leads to arrhythmic beating of Drosophila heart and of rat heart cells in culture. However, the spectrum of ion channels involved in human cardiac excitability differs from that in animal models, including mammalian models, making it difficult to evaluate the relevance of these observations to humans. Our aim was to examine the effects of celecoxib on hERG and other human channels critically involved in regulating human cardiac rhythm, and to explore the mechanisms of any observed effect on the hERG channels. Methods and Results: Celecoxib inhibited the hERG, SCN5A, KCNQ1 and KCNQ1/MinK channels expressed in HEK-293 cells with IC50s of 6.0 μM, 7.5 μM, 3.5 μM and 3.7 μM respectively, and the KCND3/KChiP2 channels expressed in CHO cells with an IC50 of 10.6 μM. Analysis of celecoxib's effects on hERG channels suggested gating modification as the mechanism of drug action. Conclusions: The above channels play a significant role in drug-induced long QT syndrome (LQTS) and short QT syndrome (SQTS). Regulatory guidelines require that all new drugs under development be tested for effects on the hERG channel prior to first administration in humans. Our observations raise the question of celecoxib's potential to induce cardiac arrhythmias or other channel related adverse effects, and make a case for examining such possibilities. [ABSTRACT FROM AUTHOR]

Melanoma is the leading cause of death from skin disease due, in large part, to its propensity to metastasize. We have examined the effect of grape seed proanthocyanidins (GSPs) on melanoma cancer cell migration and the molecular mechanisms underlying these effects using highly metastasis-specific human melanoma cell lines, A375 and Hs294t. Using in vitro cell invasion assays, we observed that treatment of A375 and Hs294t cells with GSPs resulted in a concentrationdependent inhibition of invasion or cell migration of these cells, which was associated with a reduction in the levels of cyclooxygenase (COX)-2 expression and prostaglandin (PG) E2 production. Treatment of cells with celecoxib, a COX-2 inhibitor, or transient transfection of melanoma cells with COX-2 small interfering RNA, also inhibited melanoma cell migration. Treatment of cells with 12-O-tetradecanoylphorbol-13-acetate, an inducer of COX-2, enhanced the phosphorylation of ERK1/2, a protein of mitogen-activated protein kinase family, and subsequently cell migration whereas both GSPs and celecoxib significantly inhibited 12-O-tetradecanoylphorbol-13-acetate -promoted cell migration as well as phosphorylation of ERK1/2. Treatment of cells with UO126, an inhibitor of MEK, also inhibited the migration of melanoma cells. Further, GSPs inhibited the activation of NF-kB/p65, an upstream regulator of COX-2, in melanoma cells, and treatment of cells with caffeic acid phenethyl ester, an inhibitor of NF-kB, also inhibited cell migration. Additionally, inhibition of melanoma cell migration by GSPs was associated with reversal of epithelial-mesenchymal transition process, which resulted in an increase in the levels of epithelial biomarkers (E-cadherin and cytokeratins) while loss of mesenchymal biomarkers (vimentin, fibronectin and N-cadherin) in melanoma cells. Together, these results indicate that GSPs have the ability to inhibit melanoma cell invasion/migration by targeting the endogenous expression of COX-2 and reversing the process of epithelial-to-mesenchymal transition. [ABSTRACT FROM AUTHOR]

Background: We previously demonstrated that cyclooxygenase (COX)-1 deficiency results in greater morbidity and inflammation, whereas COX-2 deficiency leads to reduced morbidity, inflammation and mortality in influenza infected mice. Methodology/Principal Findings: We investigated the effects of COX-1 and COX-2 inhibitors in influenza A viral infection. Mice were given a COX-1 inhibitor (SC-560), a COX-2 inhibitor (celecoxib) or no inhibitor beginning 2 weeks prior to influenza A viral infection (200 PFU) and throughout the course of the experiment. Body weight and temperature were measured daily as indicators of morbidity. Animals were sacrificed on days 1 and 4 post-infection and bronchoalveolar lavage (BAL) fluid was collected or daily mortality was recorded up to 2 weeks post-infection. Treatment with SC-560 significantly increased mortality and was associated with profound hypothermia and greater weight loss compared to celecoxib or control groups. On day 4 of infection, BAL fluid cells were modestly elevated in celecoxib treated mice compared to SC-560 or control groups. Viral titres were similar between treatment groups. Levels of TNF-α and G CSF were significantly attenuated in the SC-560 and celecoxib groups versus control and IL-6 levels were significantly lower in BAL fluid of celecoxib treated mice versus control and versus the SC-560 group. The chemokine KC was significantly lower in SC-560 group versus control. Conclusions/Significance: Treatment with a COX-1 inhibitor during influenza A viral infection is detrimental to the host whereas inhibition of COX-2 does not significantly modulate disease severity. COX-1 plays a critical role in controlling the thermoregulatory response to influenza A viral infection in mice. [ABSTRACT FROM AUTHOR]

Background: Many tumors are associated with decreased cellular immunity and elevated levels of prostaglandin E2 (PGE2), a known inhibitor of CD4+ T cell activation and inducer of type-2 cytokine bias. However, the role of this immunomodulator in the survival of T helper cells remained unclear. Since CD4+ T cells play critical roles in cell-mediated immunity, detail knowledge of the effect tumor-derived PGE2 might have on CD4+ T cell survival and the underlying mechanism may, therefore, help to overcome the overall immune deviation in cancer. Methodology/Principal Findings: By culturing purified human peripheral CD4+ T cells or Jurkat cells with spent media of theaflavin- or celecoxib-pre-treated MCF-7 cells, we show that tumor-shed PGE2 severely impairs interleukin 2 receptor cc (IL2Rcc)-mediated survival signaling in CD4+ T cells. Indeed, tumor-shed PGE2 down-regulates IL2Rcc expression, reduces phosphorylation as well as activation of Janus kinase 3 (Jak-3)/signal transducer and activator of transcription 5 (Stat-5) and decreases Bcl-2/Bax ratio thereby leading to activation of intrinsic apoptotic pathway. Constitutively active Stat-5A (Stat- 5A1*6) over-expression efficiently elevates Bcl-2 levels in CD4+ T cells and protects them from tumor-induced death while dominant-negative Stat-5A over-expression fails to do so, indicating the importance of Stat-5A-signaling in CD4+ T cell survival. Further support towards the involvement of PGE2 comes from the results that (a) purified synthetic PGE2 induces CD4+ T cell apoptosis, and (b) when knocked out by small interfering RNA, cyclooxygenase-2 (Cox-2)-defective tumor cells fail to initiate death. Interestingly, the entire phenomena could be reverted back by theaflavins that restore cytokinedependent IL2Rcc/Jak-3/Stat-5A signaling in CD4+ T cells thereby protecting them from tumor-shed PGE2-induced apoptosis. Conclusions/Significance: These data strongly suggest that tumor-shed PGE2 is an important factor leading to CD4+ T cell apoptosis during cancer and raise the possibility that theaflavins may have the potential as an effective immunorestorer in cancer-bearer. [ABSTRACT FROM AUTHOR]