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At least 19 recordsLinked to original sources
PubMed2005

Dimethyl-celecoxib (DMC), a derivative of celecoxib that lacks cyclooxygenase-2-inhibitory function, potently mimics the anti-tumor effects of celecoxib on Burkitt's lymphoma in vitro and in vivo.

The nonsteroidal anti-inflammatory drug (NSAID) celecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor that has shown some promising results as an anti-cancer drug. However, the question arose as to whether or not its COX-2-inhibitory function is required for its anti-tumorigenic properties. We therefore employed dimethyl-celecoxib (DMC), which is a close structural analog of celecoxib that lacks COX-2-inhibitory function, to investigate this question. By performing a combination of in vitro and in vivo studies with Burkitt's lymphoma cells, we found that DMC potently mimics all of the anti-proliferative and anti-tumorigenic effects of celecoxib. In cell culture, DMC effectively inhibits cell proliferation through the down-regulation of cyclins A and B and the ensuing loss of cyclin-dependent kinase activity. This effect appears to take place in vivo as well and results in significantly (p<.002) reduced tumor growth in experimental animals. Thus, our results demonstrate that the anti-proliferative and anti-tumorigenic properties of celecoxib and DMC are indistinguishable, at least in Burkitt's lymphoma cells, and therefore, that the COX-2-inhibitory function is not required for these effects.

Animals↗
PubMedDate not supplied

Efficacy of celecoxib in treating symptoms of viral pharyngitis: a double-blind, randomized study of celecoxib versus diclofenac.

This study compared the efficacy and safety of the cyclooxygenase-2 specific inhibitor celecoxib with the conventional non-steroidal anti-inflammatory drug diclofenac in the symptomatic treatment of viral pharyngitis. Adult patients from 27 study centers in Latin America were treated with oral doses of celecoxib 200 mg once daily or 200 mg twice daily, or diclofenac 75 mg twice daily for 5 days in a double-blind, randomized study. The primary efficacy assessment was 'Throat Pain on Swallowing' on day 3. In addition, secondary quality-of-life assessments were performed on days 3 and 5. All adverse events and treatment-emergent signs and symptoms were recorded. Data from 313 patients were evaluable for efficacy (105 celecoxib 200 mg once daily, 107 celecoxib 200 mg twice daily, 101 diclofenac 75 mg twice daily). The upper 95% confidence limits for the visual analog scale of 'Throat Pain on Swallowing' on day 3 for celecoxib 200 mg once daily relative to diclofenac 75 mg twice daily, and celecoxib 200 mg twice daily relative to diclofenac 75 mg twice daily were 9.26 and 7.83, respectively. All secondary efficacy and quality-of-life measures were clinically similar for the three treatment groups, and no statistically significant differences were detected. The incidences of treatment-emergent adverse events and withdrawals due to adverse events were similar for all groups, but numerically higher among patients taking diclofenac than celecoxib. More patients in the diclofenac group reported gastrointestinal complaints (7.3%) compared with those in the celecoxib groups (4.3% in the celecoxib 200 mg once-daily group and 3.4% in the celecoxib 200 mg twice-daily group). In conclusion, 5 days of treatment with celecoxib 200 mg once daily is as effective as diclofenac 75 mg twice daily in the symptomatic treatment of viral pharyngitis. Celecoxib 200 mg once daily is also as effective as celecoxib 200 mg twice daily in this condition.

Adolescent↗
PubMed2006

[Cytotoxic activities of Celecoxib on leukemic cells and the synergistic effects of Celecoxib with Imatinib thereupon].

OBJECTIVE: To explore the effects of Celecoxib on cell growth, early apoptosis, PRb and P27(Kip) protein expression of human leukemic cells of the line K562 and to determine its synergistic effects in combination of Imatinib. METHODS: K562 cel1s were incubated with Celecoxib of the concentrations of 0, 10, 20, 40, 80, and 160 micromol/L for 36 hours, the cell vitality was determined by MTT assay, the early apoptosis was examined by flow cytometry (FC). The percentage of annexin V positive was detected by FC so as to evaluate the early apoptosis. The expression of PRb and P27(Kip) protein was detected by Western blotting. Another K562 cells were incubated with Celecoxib of the concentration of 40 micromol/L, Imatinib of the concentration of 0.2 micromol/L, or Celecoxib 40 micromol/L + Imatinib 0.2 micromol/L for 36 hours. Then the cell vitality and early apoptosis of the cells were detected so as to evaluate the synergistic effects of the combination of Celecoxib and Imatinib. RESULTS: Celecoxib inhibited the K562 cells vitality significantly in a dose-dependent manner. The apoptotic rate of K562 cells was elevated with the increasing Celecoxib concentration. Celecoxib down-regulated the expression of PRb protein and up-regulated the expression of P27(Kip) protein in the K562 cells. The combination of Celecoxib and Imatinib exhibited evidently synergistic effects in terms of anti-proliferation on K562 cells. CONCLUSION: Celecoxib inhibits the proliferation and induces apoptosis on leukemic cells in a dose-dependent fashion. The anti-proliferation effect of Celecoxib may be associated with the down-regulation of PRb expression and up-regulation of P27(Kip) expression. Combination of Celecoxib and Imatinib has obviously synergistic effects in terms of anti-proliferation on K562 cells.

Apoptosis↗
PubMed2006

Celecoxib upregulates endoplasmic reticulum chaperones that inhibit celecoxib-induced apoptosis in human gastric cells.

Nonsteroidal anti-inflammatory drugs (NSAIDs) induce apoptosis in cancer cells and this effect is involved in their antitumor activity. We recently demonstrated that NSAIDs upregulate GRP78, an endoplasmic reticulum (ER) chaperone, in gastric mucosal cells in primary culture. In the present study, induction of ER chaperones by NSAIDs and the effect of those chaperones on NSAID-induced apoptosis were examined in human gastric carcinoma cells. Celecoxib, an NSAID, upregulated ER chaperones (GRP78 and its cochaperones ERdj3 and ERdj4) but also C/EBP homologous transcription factor (CHOP), a transcription factor involved in apoptosis. Celecoxib also upregulated GRP78 in xenograft tumors, accompanying with the suppression of tumor growth in nude mice. Celecoxib caused phosphorylation of eukaryotic translation initiation factor 2 kinase (PERK) and eukaryotic initiation factor-2alpha (eIF2alpha) and production of activating transcription factor (ATF)4 mRNA. Suppression of ATF4 expression by small interfering RNA (siRNA) partially inhibited the celecoxib-dependent upregulation of GRP78. Celecoxib increased the intracellular Ca2+ concentration, while 1,2-bis(2-aminophenoxy)ethane-N,N,N'N'-tetraacetic acid, an intracellular Ca2+ chelator, inhibited the upregulation of GRP78 and ATF4. These results suggest that the Ca2+-dependent activation of the PERK-eIF2alpha-ATF4 pathway is involved in the upregulation of ER chaperones by celecoxib. Overexpression of GRP78 partially suppressed the apoptosis and induction of CHOP in the presence of celecoxib and this suppression was stimulated by coexpression of either ERdj3 or ERdj4. On the other hand, suppression of GRP78 expression by siRNA drastically stimulated cellular apoptosis and production of CHOP in the presence of celecoxib. These results show that upregulation of ER chaperones by celecoxib protects cancer cells from celecoxib-induced apoptosis, thus may decrease the potential antitumor activity of celecoxib.

Activating Transcription Factor 4↗
PubMed2003

A randomized, clinical trial comparing oral celecoxib 200 mg, celecoxib 400 mg, and ibuprofen 600 mg for acute pain.

OBJECTIVE: Celecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor used to treat pain. The objective of this study was to compare the efficacies of celecoxib and ibuprofen for the treatment of acute pain. The null hypothesis was that no difference between celecoxib and ibuprofen exists. METHODS: The study was a prospective, randomized, double-blind, controlled clinical trial. After consent, patients rated their pain on a 100-mm visual analog scale (VAS) and categorical intensity pain scale. Patients were then randomized to receive 200-mg or 400-mg celecoxib or 600-mg ibuprofen (all orally). Patients were contacted 5 hours after receiving study medication when a second VAS score was recorded, along with categorical pain intensity, pain relief score, side effects, and number of rescue medications taken. The main outcome measures were change in visual analog pain and categorical pain intensity scores, and pain relief scores, at five hours. RESULTS: One hundred ten patients were evaluated and 105 were enrolled. Thirty-four received celecoxib 200 mg, 32 received celecoxib 400 mg, and 39 received ibuprofen 600 mg. Ninety-one were available for the five-hour VAS and 88 for the five-hour categorical pain intensity and pain relief analysis: The two patients who were unable to read a VAS were excluded, and two enrolled patients withdrew prior to medication. One patient was excluded because his injury was a fracture, and therefore did not meet the inclusion criteria. There was no statistical difference among the treatment groups in age, time from injury to medication, initial VAS score, percent lost to follow-up, or treatment with adjunctive therapy. There was no statistical difference in change of VAS among the groups at five hours: ibuprofen 600 mg (-23.8 mm [95% CI = -31.56 mm to -16.1 mm] [n = 32]), celecoxib 200 mg (-16.1 mm [95% CI = -24.3 mm to -7.98 mm] [n = 31]), and celecoxib 400 mg (-12.4 mm [95% CI = -23.1 mm to -1.8 mm] [n = 30]) (p = 0.16). There was no significant difference between the groups, at five hours, in change of categorical pain intensity (p = 0.11) or pain relief scores (p = 0.059), though the pain relief scale approached significance favoring ibuprofen. CONCLUSIONS: No significant difference exists among emergency department (ED) patients treated for acute pain, at five hours, with celecoxib 200 mg, celecoxib 400 mg, or ibuprofen 600 mg, though the power of the study to detect a change was low, 36%. However, the magnitude of pain relief for celecoxib, coupled with the cost of the medication, questions its use in the immediate ED setting.

Acute Disease↗
PubMed2000

Gastrointestinal toxicity with celecoxib vs nonsteroidal anti-inflammatory drugs for osteoarthritis and rheumatoid arthritis: the CLASS study: A randomized controlled trial. Celecoxib Long-term Arthritis Safety Study.

CONTEXT: Conventional nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with a spectrum of toxic effects, notably gastrointestinal (GI) effects, because of inhibition of cyclooxygenase (COX)-1. Whether COX-2-specific inhibitors are associated with fewer clinical GI toxic effects is unknown. OBJECTIVE: To determine whether celecoxib, a COX-2-specific inhibitor, is associated with a lower incidence of significant upper GI toxic effects and other adverse effects compared with conventional NSAIDs. DESIGN: The Celecoxib Long-term Arthritis Safety Study (CLASS), a double-blind, randomized controlled trial conducted from September 1998 to March 2000. SETTING: Three hundred eighty-six clinical sites in the United States and Canada. PARTICIPANTS: A total of 8059 patients (>/=18 years old) with osteoarthritis (OA) or rheumatoid arthritis (RA) were enrolled in the study, and 7968 received at least 1 dose of study drug. A total of 4573 patients (57%) received treatment for 6 months. INTERVENTIONS: Patients were randomly assigned to receive celecoxib, 400 mg twice per day (2 and 4 times the maximum RA and OA dosages, respectively; n = 3987); ibuprofen, 800 mg 3 times per day (n = 1985); or diclofenac, 75 mg twice per day (n = 1996). Aspirin use for cardiovascular prophylaxis (</=325 mg/d) was permitted. MAIN OUTCOME MEASURES: Incidence of prospectively defined symptomatic upper GI ulcers and ulcer complications (bleeding, perforation, and obstruction) and other adverse effects during the 6-month treatment period. RESULTS: For all patients, the annualized incidence rates of upper GI ulcer complications alone and combined with symptomatic ulcers for celecoxib vs NSAIDs were 0.76% vs 1.45% (P =.09) and 2. 08% vs 3.54% (P =.02), respectively. For patients not taking aspirin, the annualized incidence rates of upper GI ulcer complications alone and combined with symptomatic ulcers for celecoxib vs NSAIDs were 0.44% vs 1.27% (P =.04) and 1.40% vs 2.91% (P =.02). For patients taking aspirin, the annualized incidence rates of upper GI ulcer complications alone and combined with symptomatic ulcers for celecoxib vs NSAIDs were 2.01% vs 2.12% (P =.92) and 4.70% vs 6.00% (P =.49). Fewer celecoxib-treated patients than NSAID-treated patients experienced chronic GI blood loss, GI intolerance, hepatotoxicity, or renal toxicity. No difference was noted in the incidence of cardiovascular events between celecoxib and NSAIDs, irrespective of aspirin use. CONCLUSIONS: In this study, celecoxib, at dosages greater than those indicated clinically, was associated with a lower incidence of symptomatic ulcers and ulcer complications combined, as well as other clinically important toxic effects, compared with NSAIDs at standard dosages. The decrease in upper GI toxicity was strongest among patients not taking aspirin concomitantly. JAMA. 2000;284:1247-1255

Aged↗
PubMed2006

Downregulation of survivin expression and concomitant induction of apoptosis by celecoxib and its non-cyclooxygenase-2-inhibitory analog, dimethyl-celecoxib (DMC), in tumor cells in vitro and in vivo.

BACKGROUND: 2,5-Dimethyl-celecoxib (DMC) is a close structural analog of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib (Celebrex) that lacks COX-2-inhibitory function. However, despite its inability to block COX-2 activity, DMC is able to potently mimic the anti-tumor effects of celecoxib in vitro and in vivo, indicating that both of these drugs are able to involve targets other than COX-2 to exert their recognized cytotoxic effects. However, the molecular components that are involved in mediating these drugs' apoptosis-stimulatory consequences are incompletely understood. RESULTS: We present evidence that celecoxib and DMC are able to down-regulate the expression of survivin, an anti-apoptotic protein that is highly expressed in tumor cells and known to confer resistance of such cells to anti-cancer treatments. Suppression of survivin is specific to these two drugs, as other coxibs (valdecoxib, rofecoxib) or traditional NSAIDs (flurbiprofen, indomethacin, sulindac) do not affect survivin expression at similar concentrations. The extent of survivin down-regulation by celecoxib and DMC in different tumor cell lines is somewhat variable, but closely correlates with the degree of drug-induced growth inhibition and apoptosis. When combined with irinotecan, a widely used anticancer drug, celecoxib and DMC greatly enhance the cytotoxic effects of this drug, in keeping with a model that suppression of survivin may be beneficial to sensitize cancer cells to chemotherapy. Remarkably, these effects are not restricted to in vitro conditions, but also take place in tumors from drug-treated animals, where both drugs similarly repress survivin, induce apoptosis, and inhibit tumor growth in vivo. CONCLUSION: In consideration of survivin's recognized role as a custodian of tumor cell survival, our results suggest that celecoxib and DMC might exert their cytotoxic anti-tumor effects at least in part via the down-regulation of survivin - in a manner that does not require the inhibition of cyclooxygenase-2. Because inhibition of COX-2 appears to be negligible, it might be worthwhile to further evaluate DMC's potential as a non-coxib alternative to celecoxib for anti-cancer purposes.

Animals↗
PubMed2006

Antitumor properties of dimethyl-celecoxib, a derivative of celecoxib that does not inhibit cyclooxygenase-2: implications for glioma therapy.

Celecoxib (Celebrex) appears to be unique among the class of selective COX-2 inhibitors (coxibs), because this particular compound exerts a second function that is independent of its celebrated ability to inhibit COX-2. This second function is the potential to inhibit cell proliferation and stimulate apoptotic cell death at much lower concentrations than any other coxibs. Intriguingly, these two functions are mediated by different moieties of the celecoxib molecule and can be separated. The author, as well as others, have generated and investigated analogs of celecoxib that retain only one of these two functions. One derivative, 2,5-dimethyl-celecoxib (DMC), which retains the antiproliferative and apoptosis-inducing function, but completely lacks the COX-2 inhibitory activity, is able to mimic faithfully all of the numerous antitumor effects of celecoxib that have been investigated so far, including reduction of neovascularization and inhibition of experimental tumor growth in various in vivo tumor models. In view of the controversy that has recently arisen regarding the life-threatening side effects of this class of coxibs, it may be worthwhile to pursue further the potential benefits of drugs such as DMC for anticancer therapy. Because DMC is not a coxib yet potently maintains celecoxib's antitumor potential, one may be inclined to speculate that this novel compound could potentially be advantageous in the management of COX-2-independent cancers. In this summary, the implications of recent findings with DMC will be presented and discussed.

Angiogenesis Inhibitors↗
PubMed2005

Multitarget inhibition of drug-resistant multiple myeloma cell lines by dimethyl-celecoxib (DMC), a non-COX-2 inhibitory analog of celecoxib.

2,5-Dimethyl-celecoxib (DMC) is a close structural analog of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib that lacks COX-2 inhibitory function. We and others have demonstrated that DMC, despite its inability to block COX-2, is able to potently mimic the antitumor effects of celecoxib in vitro and in vivo. In this current study, we investigated whether DMC would also be able to inhibit the growth of highly drug-resistant tumor cell variants. We focused on human multiple myeloma (MM) cells, as patients with MM frequently develop drug-resistant disease and ultimately succumb to death. Here we show that DMC (and celecoxib) inhibits the proliferation of various multiple myeloma cell lines, including several (multi) drug-resistant variants. Growth inhibition in drug-sensitive and drug-resistant cells is mediated via multiple effects, which include diminished signal transducer and activator of transcription 3 (STAT-3) and mitogen-activated protein (MAP) kinase kinase (MEK) activity, reduced expression of survivin and various cyclins, and is followed by apoptotic cell death. Thus, our study demonstrates that inhibition of proliferation and induction of apoptosis by DMC (and celecoxib) can be accomplished even in highly drug-resistant multiple myeloma cells, and that this effect is achieved via the blockage of multiple targets that are critical for multiple myeloma cell growth and survival.

Cell Line, Tumor↗
PubMed2006

Single periocular injection of celecoxib-PLGA microparticles inhibits diabetes-induced elevations in retinal PGE2, VEGF, and vascular leakage.

PURPOSE: To determine whether celecoxib inhibits VEGF secretion from ARPE-19 cells and to investigate further the safety and effectiveness of periocular celecoxib-poly (lactide-co-glycolide; PLGA) microparticles in inhibiting elevations in retinal PGE(2), VEGF, and blood-tissue barrier leakage at the end of 60 days in a streptozotocin diabetic rat model. METHODS: VEGF mRNA and protein expression in ARPE-19 cells was evaluated in the presence of 0 to 10 microM celecoxib, and cytotoxicity of celecoxib on ARPE-19 and RF6A cells was evaluated over a 0- to 100-microM concentration range. Celecoxib-PLGA microparticles were prepared by a modified solvent evaporation technique, sterilized by 25 kGy of gamma-irradiation, and characterized for size, zeta potential, drug loading, and in vitro release. Normal and streptozotocin-diabetic male Sprague-Dawley rats were divided into five groups: normal, diabetic, diabetic+placebo, normal+celecoxib, and diabetic+celecoxib. Phosphate-buffered saline (PBS) containing celecoxib-PLGA microparticles, placebo PLGA microparticles, or plain PBS in one eye was injected into the posterior subconjunctival (periocular) space in rats under anesthesia. Sixty days after administration, the animals were killed, and retinal PGE2 secretion, VEGF protein, and blood-retinal barrier leakage were estimated. Blood cell counts, blood chemistry and histology were used to assess the safety of the microparticulate system. RESULTS: Celecoxib (up to 25 microM) did not cause significant cytotoxicity in ARPE-19 or RF6A cells. Nanomolar concentrations of celecoxib reduced VEGF mRNA and VEGF protein secretion. Celecoxib-PLGA microparticles (diameter: 1140 +/- 15 nm), containing 14.93% +/- 0.21% of celecoxib sustained in vitro drug release and in vivo drug levels in the retina for 60 days. Diabetes elevated PGE2 secretion, VEGF protein, the vitreous-plasma protein ratio, and blood-retinal barrier leakage by 3-, 1.7-, 3.1-, and 2.7-fold, and celecoxib-PLGA microparticles significantly reduced these elevations by 40%, 50%, 40%, and 50%, respectively. Neither the placebo-treated eyes nor the contralateral eyes in celecoxib-PLGA microparticle-treated rats showed significant effects. Celecoxib-PLGA or placebo-PLGA particles had no effect on the body weight or blood sugar level of rats. The celecoxib-PLGA microparticles did not cause any changes in blood cell counts or chemistry and caused no histopathological damage to the retina or periocular tissues. CONCLUSIONS: Nanomolar concentrations of celecoxib can inhibit VEGF mRNA and protein expression from ARPE-19 cells. Periocular celecoxib microparticles are useful sustained drug delivery systems for inhibiting diabetes-induced elevations in PGE2, VEGF, and blood-retinal barrier leakage. The periocular celecoxib-PLGA microparticles are safe and do not cause any damage to the retina.

Animals↗
PubMed2004

Celecoxib simulates respiratory burst through pertussis toxin-sensitive G-protein, a possible signal for beta 2-integrin expression on human neutrophils.

The superoxide anion-generating effect of celecoxib (4-[5-(4-methylpheny)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide); SC58633), a selective cyclooxygenase-2 inhibitor, on human neutrophils was evaluated in this study. Celecoxib induced superoxide anion generation in a concentration-dependent manner in human neutrophils. The EC50 value of celecoxib on superoxide anion generation was 15.5+/-2.5 microM. A NADPH oxidase inhibitor, diphenyliodonium (20 microM), and superoxide dismutase (150 U/ml) completely inhibited the free radical generation caused by celecoxib, indicating that the respiratory burst was activated by celecoxib. 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA/AM;10 microM) and staurosporine (200 nM) completely inhibited the superoxide anion release caused by celecoxib, respectively. These data indicated that celecoxib increased superoxide anion release by increasing intracellular calcium and protein kinase C activation. Moreover, 12-(2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo(2,3-a)pyrrolo(3,4-C)-carbazole (Go-6976; 1 microM) and 3-[1-[3-(amidinothio)propyl-1H-indol-3-yl]-3-(1-methyl-1H-indol-3-yl)maleimide, methane sulfate (Ro-31-8220; 0.5 microM), specific inhibitors of conventional protein kinase C isotypes (alpha, beta(I) and beta(II)), significantly inhibited superoxide anion release caused by celecoxib. Rottlerin (5 microM), a protein kinase C delta inhibitor, did not affect the free radical generation caused by celecoxib. Celecoxib caused translocation of protein kinase C alpha, beta(I) and beta(II) from the cytosol to the cellular membrane. 2-[2-amino-3-methoxyphenyl]-4H-1-benzopyran-4-one (PD98059; 20 microM) and wortmannin (100 nM) did not decrease the superoxide anion generation caused by celecoxib, indicating that Mitogen-activated protein (MAP) kinase and phosphatidylinositol 3-kinase (PI3 kinase) were not involved in the respiratory burst induced by celecoxib. Pertussis toxin (2 microg/ml), a Gi-protein sensitive inhibitor, significantly inhibited superoxide anion release. Moreover, pertussis toxin significantly inhibited intracellular calcium mobilization and protein kinase C alpha, beta(I) and beta(II) translocation from the cytosol to the membrane. Celecoxib increased beta(2)-integrin expression on human neutrophils and this effect was inhibited by BAPTA/AM (10 microM), superoxide dismutase (150 U/ml), genistein (25 microM) and PD98059 (20 microM). This information indicated that intracellular calcium, superoxide anion, tyrosine kinase and MAP kinase are involved in beta(2)-integrin expression. Furthermore, BAPTA/AM, superoxide dismutase and genistein inhibited celecoxib-increased MAP kinase activity, indicating that MAP kinase is a downstream signal for beta(2)-integrin expression. In conclusion, celecoxib stimulates superoxide anion release from human neutrophils by activating pertussis toxin sensitive G-protein. An increase in intracellular calcium and protein kinase C alpha, beta(I) and beta(II) is involved in this process. Celecoxib also regulates beta(2)-integrin expression through superoxide anion release, tyrosine kinase and p42/p44 MAP kinase on human neutrophils.

Adult↗
PubMed2005

Subconjunctivally administered celecoxib-PLGA microparticles sustain retinal drug levels and alleviate diabetes-induced oxidative stress in a rat model.

We have previously reported that repeated oral doses of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, reduced diabetes-induced retinal vascular endothelial growth factor (VEGF) expression [Ayalasomayajula, S.P., Kompella, U.B., 2003. Celecoxib, a selective cyclooxygenase-2 inhibitor, inhibits retinal vascular endothelial growth factor expression and vascular leakage in a streptozotocin-induced diabetic rat model. Eur J Pharmacol 458, 283-289] and that retinal celecoxib delivery can be improved by several-fold following subconjunctival administration [Ayalasomayajula, S.P., Kompella, U.B., 2004. Retinal delivery of celecoxib is several-fold higher following subconjunctival administration compared to systemic administration. Pharm Res 21, 1797-1804]. The objective of the current study was to determine whether polymeric microparticles of celecoxib sustain retinal drug levels following subconjunctival administration and alleviate diabetes-induced oxidative stress in a streptozotocin-induced diabetic rat model. Biodegradable poly (lactide-co-glycolide) (PLGA; 85:15) microparticles of celecoxib were prepared using solvent evaporation method and characterized for their size, morphology, encapsulation efficiencies, and in vitro release. The celecoxib-PLGA microparticles or solution containing 75 microg of celecoxib was administered subconjunctivally to one eye (ipsilateral) of Sprague Dawley rats and drug levels in the retina, vitreous, lens, and cornea of ipsilateral and contralateral eyes were determined on 1, 7, and 14 days using high-performance liquid chromatography (HPLC). The effect of subconjunctivally administered celecoxib-PLGA microparticles on oxidative stress in day 14 diabetic rat retinas was determined by measuring the retinal glutathione (reduced (GSH) and oxidized (GSSG)), thiobarbituric acid reactive substances, and 4-hydroxynonenal levels using spectrofluorometric and colorimetric methods. Solvent evaporation method produced spherical celecoxib-PLGA microparticles with mean diameters of 3.9+/-0.6 microm and 68.5% loading efficiency. These microparticles sustained celecoxib release during the 49-day in vitro release study. Subconjunctivally administered celecoxib-PLGA microparticles sustained retinal and other ocular tissue drug levels during the 14-day study in rats. No detectable celecoxib levels were observed in the contralateral eye. The celecoxib-PLGA microparticles significantly inhibited the diabetes-induced increases in thiobarbituric acid reactive substance (P=0.012) and 4-hydroxynonenal levels (P=0.029). The particles also inhibited the GSH depletion and the increase in GSSH/GSH ratio associated with diabetes but the effects were not statistically significant (P=0.12). Thus, following subconjunctival administration, celecoxib-PLGA microparticles sustained retinal celecoxib delivery and inhibited diabetes-induced retinal oxidative damage, indicating their potential usefulness in treating diabetes-induced retinal abnormalities.

Aldehydes↗
PubMed2000

Celecoxib: a review of its use in osteoarthritis, rheumatoid arthritis and acute pain.

UNLABELLED: Celecoxib is a cyclo-oxygenase (COX) inhibitor that exhibits relative in vitro and ex vivo selectivity for COX-2 over COX-1. Results of randomised double-blind multicentre studies indicate that celecoxib is superior to placebo and has similar efficacy as conventional nonsteroidal anti-inflammatory drugs (NSAIDs) in improving the signs and symptoms of osteoarthritis and rheumatoid arthritis. Analgesic efficacy and improvements in functional status are apparent within 2 weeks of starting therapy and are maintained throughout treatment. Available data suggest that celecoxib has analgesic efficacy in patients with postsurgical dental pain, although this is yet to be confirmed. In patients with osteoarthritis of the knee, celecoxib 100 and 200 mg and naproxen 500 mg twice daily were similarly efficacious and superior to placebo. Once and twice daily celecoxib dosage regimens provided comparable efficacy. Improvements in physical function paralleled those in pain relief. Celecoxib also has efficacy in treating the signs and symptoms of osteoarthritis of the hip. The effects of celecoxib were not diminished in elderly patients with osteoarthritis of the hip or knee. All dosages of celecoxib (100 to 400 mg twice daily) and naproxen 500 mg twice daily produced significant anti-inflammatory and analgesic effects in patients with active rheumatoid arthritis. In patients with stable rheumatoid arthritis, celecoxib 200 mg twice daily showed sustained symptomatic improvements similar to those of twice daily slow-release diclofenac 75 mg over a 24-week period. Celecoxib was well tolerated in clinical trials. Upper gastrointestinal complications occurred in significantly fewer patients treated with twice daily celecoxib 25 to 400 mg than in those receiving comparator NSAIDs. There was no evidence of a dose relationship in endoscopic ulcer development and incidences in celecoxib and placebo recipients were lower than in those receiving twice daily naproxen 500 mg or ibuprofen 800 mg 3 times daily. CONCLUSIONS: Celecoxib is the first COX-2 specific inhibitor approved for use in osteoarthritis and rheumatoid arthritis. Celecoxib produces significant improvements in pain and inflammation and these effects are maintained during treatment for up 24 weeks in clinical trials. Studies indicate that celecoxib has similar efficacy to conventional NSAIDs in relieving pain and improving functional status, but is associated with a lower incidence of upper gastrointestinal ulceration and complications. This promising gastrointestinal safety profile, together with sustained symptomatic relief, places celecoxib as a useful alternative for the treatment of osteoarthritis and rheumatoid arthritis, particularly in patients at high risk of developing gastrointestinal events. Although data are encouraging, its place in acute pain states remains to be established.

Acute Disease↗
PubMed2003

Celecoxib inhibits proliferation and induces apoptosis via prostaglandin E2 pathway in human cholangiocarcinoma cell lines.

AIM: To evaluate the roles and mechanisms of celecoxib in inducing proliferation inhibition and apoptosis of human cholangiocarcinoma cell lines. METHODS: Cyclooxygenase-2-overexpressing human cholangiocarcinoma cell line QBC939 and cyclooxygenase-2-deficient human cholangiocarcinoma cell line SK-CHA-1 were used in the present study. The anti-proliferative effect was measured by methabenzthiazuron (MTT) assay; apoptosis was determined by transferase-mediated dUTP nick end labeling (TUNEL) detection and transmission electron microscopy (TEM). Cell cycle was analyzed by flow cytometry (FCM). The PGE(2) levels in the supernatant of cultured cholangiocarcinoma cells were quantitated by enzyme-linked immunoabsordent assay (ELISA). RESULTS: Celecoxib suppressed the production of PGE(2) and inhibited the growth of QBC939 cells. Celecoxib at 10, 20, and 40 micromol/L inhibited PGE(2) production by 26 %, 58 %, and 74 % in QBC939 cells. The PGE(2) level was much lower constitutively in SK-CHA-1 cells (18.6+/-3.2) compared with that in QBC939 (121.9+/-5.6) cells (P<0.01) and celecoxib had no significant influence on PGE(2) level in the SK-CHA-1 cells. The PGE(2) concentration in SK-CHA-1 cells also reduced but not significantly after treatment with celecoxib. The PGE(2) concentration in SK-CHA-1 cells was (16.5+/-2.9) ng/well, (14.8+/-3.4) ng/well, (13.2+/-2.0) ng/well and (12.6+/-3.1) ng/well respectively, when pre-treated with 1 micromol/L, 10 micromol/L, 20 micromol/L and 40 micromol/L of celecoxib for 48 h (P>0.05, vs control). The anti-proliferation effect of celecoxib (20 micromol/L) on QBC939 cells was time-dependent, it was noticeable on day 2 (OD490=0.23+/-0.04) and became obvious on day 3 (OD490=0.31+/-0.07) to day 4 (OD490= 0.25+/-0.06), and the OD490 in the control group (day 1) was 0.12+/-0.03 (P<0.01, vs control). The anti-proliferation effect of celecoxib could be abolished by the addition of 200 pg/mL PGE(2). The proliferation of SK-CHA-1 cells was inhibited slightly by celecoxib, the cell density OD490 in the presence of celecoxib and in control group was 0.31+/-0.04 and 0.42+/-0.03 respectively on day 2 (P>0.05), 0.58+/-0.07 and 0.67+/-0.09 respectively on day 3 (P>0.05), and 0.71+/-0.08 and 0.78+/-0.06 respectively on day 4 (P>0.05). Celecoxib induced proliferation inhibition and apoptosis by G(1)-S cell cycle arrest: the percentage of QBC939 cells in G(0)-G(1) phase after treatment with 40 micromol/L (74.66+/-6.21) and 20 micromol/L (68.63+/-4.36) celecoxib increased significantly compared with control cells (54.41+/-5.12, P<0.01). The percentage of SK-CHA-1 cells in G(0)-G(1) phase after treatment with various concentrations of celecoxib didn't change significantly compared with control cells. The TUNEL index was much higher in QBC939 cells treated with 20 micromol/L celecoxib for 2 d (0.063+/-0.018) and for 4 d (0.102+/-0.037) compared with control cells (0.017+/-0.004, P<0.01). CONCLUSION: The current in vitro study indicates that inhibition of proliferation and induction of apoptosis in human cholangiocarcinoma cells by cyclooxygenase-2 specific inhibitor celecoxib may involve in COX-dependent mechanisms and PGE(2) pathway. Celecoxib as a chemopreventive and chemotherapeutic agent might be effective primarily on COX-2-expressing cholangiocarcinoma.

Antineoplastic Agents↗
PubMed2000

Chemoprevention of colon cancer by specific cyclooxygenase-2 inhibitor, celecoxib, administered during different stages of carcinogenesis.

Epidemiological observations and laboratory research have suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the risk of colon cancer and that the inhibition of colon carcinogenesis by NSAIDs is mediated through the modulation of prostaglandin production by rate-limiting enzymes known as cyclooxygenases (COXs). Because traditional NSAIDs inhibit both COX-1 and COX-2, these drugs induce side effects, such as gastrointestinal ulceration and renal toxicity, through the inhibition of the constitutive COX-1. Overexpression of COX-2 has been observed in colon tumors; therefore, specific inhibitors of COX-2 could serve as chemopreventive agents. Our previous study has shown that celecoxib, an inhibitor of COX-2, while sparing COX-1, inhibited azoxymethane (AOM)-induced colon tumorigenesis when administered during both initiation and postinitiation stages, ie., celecoxib administered continuously before, during, and after carcinogen treatment. This study examined the dose-response effect of celecoxib when administered during the initiation and postinitiation stages. In addition, the chemopreventive effects of high-dose celecoxib administered during the promotion/progression stage of colon carcinogenesis, ie., continuous celecoxib administration beginning 14 weeks after the carcinogen treatment, was determined in male F344 rats. We also measured the steady-state levels of celecoxib in the plasma of animals given this inhibitor. Groups of 5-week-old male F344 rats were fed either a control diet or experimental diets containing 500, 1000, or 1500 ppm celecoxib. At 7 and 8 weeks of age, rats scheduled for carcinogen treatment were injected s.c. with AOM at a dose rate of 15 mg/kg body weight/week. Groups of animals destined for the promotion/ progression study and initially receiving the control diet were switched to a diet containing 1500 ppm celecoxib beginning 14 weeks after the second AOM treatment. All rats remained on their respective dietary regimens until the termination of the study, ie., 52 weeks, and were then sacrificed. Colon tumors were evaluated histopathologically. Administration of 500, 1000, or 1500 ppm celecoxib during the initiation and postinitiation stages significantly inhibited the incidence (P < 0.01 to P < 0.0001) as well as the multiplicity (P < 0.01 to P < 0.0001) of adenocarcinomas of the colon in a dose-dependent manner. Importantly, administration of 1500 ppm celecoxib during the promotion/progression stage also significantly suppressed the incidence and multiplicity of adenocarcinomas of the colon (P < 0.01). Also, administration of celecoxib to the rats during the initiation and postinitiation periods and throughout the promotion/progression stage strongly suppressed colon tumor volume (P < 0.0002 to P < 0.001). The steady-state plasma concentration of celecoxib increases somewhat with the dose. Thus, in this model system, the chemopreventive efficacy of celecoxib is dose-dependent when this COX-2 inhibitor is administered during the initiation and postinitiation periods. This study provides the first evidence that celecoxib is also very effective when it is given during the promotion/progression stage of colon carcinogenesis, indicating that the chemopreventive efficacy is achieved during the later stages of colon tumor development. This suggests that celecoxib may potentially be an effective chemopreventive agent for the secondary prevention of colon cancer in patients with familial adenomatous polyposis and sporadic polyps.

Administration, Oral↗
PubMed2000

Upper gastrointestinal tolerability of celecoxib, a COX-2 specific inhibitor, compared to naproxen and placebo.

OBJECTIVE: To determine the upper gastrointestinal (GI) tolerability of celecoxib, naproxen, and placebo in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: An analysis of 5, 12-week, randomized, double blind, parallel group, placebo controlled clinical trials was conducted. In these trials, patients were randomized to: naproxen 500 mg bid (n = 1,099), placebo (n = 1,136), celecoxib 50 mg bid (n = 690) (subtherapeutic dose), celecoxib 100 mg (n = 1,131) or 200 mg bid (n = 1,125) (therapeutic dose), or celecoxib 400 mg bid (n = 434) (supratherapeutic dosage). The incidence and time until moderate to severe abdominal pain, dyspepsia, nausea, and any of the aforementioned 3 upper GI symptoms (composite endpoint) were determined using time-to-event analysis. RESULTS: The cumulative incidences of moderate to severe abdominal pain, dyspepsia, or nausea (composite endpoint) were: naproxen 500 mg (12.0%; 95% CI 9.9%-14.0%), celecoxib 50 mg bid (7.1%; 95% CI 5.0%-9.2%), celecoxib 100 mg bid (7.8%; 95% CI 6.0%-9.5%), celecoxib 200 mg bid (8.1%; 95% CI 6.4%-9.9%), celecoxib 400 mg bid (6.0%; 95% CI 3.6%-8.4%), and placebo (8.5%; 95% CI 6.5%-10.8%). After controlling for independent predictors of the composite endpoint, relative risks (RR) for the various treatments relative to naproxen 500 mg bid were: celecoxib 50 mg (RR 0.54; 95% CI 0.37-0.77; p < 0.001), celecoxib 100 mg (RR 0.60; 95% CI 0.45-0.80; p < 0.001), celecoxib 200 mg bid (RR 0.63; 95% CI 0.47-0.83; p = 0.001), celecoxib 400 mg bid (RR 0.56; 95% CI 0.35-0.89; p = 0.015), and placebo (RR 0.63; 95% CI 0.47-0.85; p = 0.002). After controlling for independent predictors of the composite endpoint, celecoxib treatment group patients did not differ from placebo patients when reporting the composite endpoint, with p values ranging from 0.40 to 0.96. CONCLUSION: The upper GI tolerability of celecoxib is superior to naproxen. A dose-response relationship between celecoxib and upper GI symptoms was not apparent.

Abdominal Pain↗