celecoxib, Celebrex
The Cyclooxygenase-2 Inhibitor GW406381X [2-(4-Ethoxyphenyl)-3-[4-(methylsulfonyl)phenyl]-pyrazolo[1,5-b]pyridazine] Is Effective in Animal Models of Neuropathic Pain and Central Sensitization.

Bingham S, Beswick PJ, Bountra C, Brown T, Campbell IB, Chessell IP, Clayton N, Collins SD, Davey PT, Goodland H, Gray N, Haslam C, Hatcher JP, Hunter AJ, Lucas F, Murkitt G, Naylor A, Pickup E, Sargent B, Summerfield SG, Stevens A, Stratton SC, Wiseman J.

Pain Research Department, Neurology and Gastrointestinal Centre of Excellence for Drug Discovery, GlaxoSmithKline Pharmaceuticals, 3rd Avenue, Harlow, Essex CM19 5AW, UK. sharon_bingham-1 gsk.com.

The pathogenic form of the cyclooxygenase (COX) enzyme, COX-2, is also constitutively present in the spinal cord and has been implicated in chronic pain states in rat and man. A number of COX-2 inhibitors, including celecoxib and rofecoxib, are already used in man for the treatment of inflammatory pain. Preclinically, the dual-acting COX-2 inhibitor, GW406381X [2-(4-ethoxyphenyl)-3-[4-(methylsulfonyl)phenyl]-pyrazolo[1,5-b]pyridazine, where X denotes the free base], is as effective as rofecoxib and celecoxib in the rat established Freund's Complete Adjuvant model with an ED(50) of 1.5 mg/kg p.o. compared with 1.0 mg/kg p.o. for rofecoxib and 6.6 mg/kg p.o. for celecoxib. However, in contrast to celecoxib (5 mg/kg p.o. b.i.d.) and rofecoxib (5 mg/kg p.o. b.i.d.), which were without significant effect, GW406381X (5 mg/kg p.o. b.i.d.) fully reversed mechanical allodynia in the chronic constriction injury model and reversed thermal hyperalgesia in the mouse partial ligation model, both models of neuropathic pain. GW406381X, was also effective in a rat model of capsaicin-induced central sensitization, when given intrathecally (ED(50) = 0.07 mug) and after chronic but not acute oral dosing. Celecoxib and rofecoxib had no effect in this model. Several hypotheses have been proposed to try to explain these differences in efficacy, including central nervous system penetration, enzyme kinetics, and potency. The novel finding of effectiveness of GW406381X in these models of neuropathic pain/central sensitization, in addition to activity in inflammatory pain models and together with its central efficacy, suggests dual activity of GW406381X compared with celecoxib and rofecoxib, which may translate into greater efficacy in a broader spectrum of pain states in the clinic.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15572651&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Death receptor regulation and celecoxib-induced apoptosis in human lung cancer cells.

Liu X, Yue P, Zhou Z, Khuri FR, Sun SY.

Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA.

BACKGROUND: Celecoxib, a cyclooxygenase 2 inhibitor, has chemopreventive and therapeutic activities toward lung cancer and other epithelial malignancies. Celecoxib can induce apoptosis in various cancer cell lines through a mechanism that is independent of its cyclooxygenase 2 inhibitory activity but is otherwise largely uncharacterized. We investigated the mechanism of celecoxib-induced apoptosis further. METHODS: All experiments were conducted in human non-small-cell lung carcinoma (NSCLC) cell lines; results in celecoxib-treated and untreated cells were compared. Cell survival was assessed with a sulforhodamine B assay. Apoptosis was assessed by DNA fragmentation with an enzyme-linked immunosorbent assay, by terminal deoxynucleotidyltransferase-mediated dUTP nick-end-labeling (TUNEL) assay, and by western blot analysis of caspase activation. Death receptor gene and protein expression was detected by northern and western blot analysis, respectively. Gene silencing was achieved with small interfering RNA (siRNA) technology. RESULTS: Celecoxib treatment decreased cell survival, activated caspase cascades, and increased DNA fragmentation, all of which were abrogated when caspase 8 expression was silenced with caspase 8 siRNA. Celecoxib treatment induced the expression of death receptors, particularly that of DR5. Overexpression of a dominant negative Fas-associated death domain mutant, but not of BCL2, reduced the level of celecoxib-induced apoptosis, and silencing of DR5 expression by DR5 siRNA suppressed celecoxib-induced caspase 8 activation and apoptosis. Combination treatment with celecoxib and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induced additional apoptosis. For example, survival of A549 cells was decreased with 50 muM celecoxib alone by 38.7% (95% confidence interval [CI] = 35.2% to 42.2%), with TRAIL alone by 29.3% (95% CI = 25.1% to 33.6%), but with their combination by 77.5% (95% CI = 74.5% to 79.5%), a greater than additive effect. CONCLUSION: Celecoxib appears to induce apoptosis in human NSCLC through the extrinsic death receptor pathway.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15572759&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Formulation design of self-microemulsifying drug delivery systems for improved oral bioavailability of celecoxib.

Subramanian N, Ray S, Ghosal SK, Bhadra R, Moulik SP.

Division of Pharmaceutics, Department of Pharmaceutical Technology, Jadavpur University, India.

Celecoxib is a hydrophobic and highly permeable drug belonging to class II of biopharmaceutics classification system. Low aqueous solubility of celecoxib leads to high variability in absorption after oral administration. Cohesiveness, low bulk density and compressibility, and poor flow properties of celecoxib impart complications in it's processing into solid dosage forms. To improve the solubility and bioavailability and to get faster onset of action of celecoxib, the self-microemulsifying drug delivery system (SMEDDS) was developed. Composition of SMEDDS was optimized using simplex lattice mixture design. Dissolution efficiency, t(85%), absorbance of diluted SMEDDS formulation and solubility of celecoxib in diluted formulation were chosen as response variables. The SMEDDS formulation optimized via mixture design consisted of 49.5% PEG-8 caprylic/capric glycerides, 40.5% mixture of Tween20 and Propylene glycol monocaprylic ester (3:1) and 10% celecoxib, which showed significantly higher rate and extent of absorption than conventional capsule. The relative bioavailability of the SMEDDS formulation to the conventional capsule was 132%. The present study demonstrated the suitability of mixture design to optimize the compositions for SMEDDS. The developed SMEDDS formulations have the potential to minimize the variability in absorption and to provide rapid onset of action of celecoxib.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15577219&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
[Inhibitory Effects of Celecoxib Combined with Octreotide on Growth of Multidrug Resistant Human Gastric Cancer Cell Line SGC7901/ADR.]

[Article in Chinese]

Zheng WB, Wang CH, Qiang O, Tang CW.

Division of Peptides Related with Human Diseases,Key Laboratory of Biotherapy of Human Diseases, Ministry of Education,West China Hospital,Sichuan University, Chengdu,Sichuan,610041, P.R.China. cwtang57 yahoo.com.cn.

BACKGROUND & OBJECTIVE: Both cyclooxygenase-2 (COX-2) inhibitor and octreotide can inhibit growth of tumor cells. This study was to investigate inhibitory effects of COX-2 inhibitor celecoxib alone, and celecoxib combined with octreotide on growth of multidrug resistant human gastric cancer cell line SGC7901/ADR. METHODS: Experimental groups:(1)celecoxib (1x10(-4)-1x10(-8) mol/L); (2)octreotide (1x10(-5)-1x10(-9) mol/L); (3)celecoxib (1x10(-4)-1x10(-8) mol/L) combined with octreotide (1x10-6 mol/L);(4)control group (RPMI-1640 medium without serum). The effects of all treatments on SGC7901 cells, and SGC7901/ADR cells were observed. Cell proliferation was measured by (3)H-thymidine incorporation into DNA. The expression of proliferating cell nuclear antigen (PCNA) was detected by immunocytochemistry. Cell apoptosis was measured by TdT-mediated dUTP nick end-labeling assay (TUNEL) and flow cytometry. RESULTS: (3)H-thymidine incorporation into SGC7901/ADR cells treated with celecoxib [(471.3+/-79.7) cpm] was significantly lower than that of control group [(917.5+/-130.8) cpm](P< 0.05). When combined with octreotide, celecoxib presented lower (3)H-thymidine incorporation [(220.0+/-19.7)cpm] than it alone with a 53.3% decrease. The concentration of celecoxib in combination group negatively related to synthesis of DNA in SGC7901/ADR cells (r=0.996,P< 0.001). The expression of PCNA in either celecoxib group or combination group markedly decreased. The apoptosis rates of SGC7901/ADR cells induced by celecoxib alone, and combination treatment were 32.9%, and 52.5%. CONCLUSION: Celecoxib combined with octreotide may enhance inhibition of growth of multidrug resistant human gastric cancer cells. The mechanism may be related with inhibiting DNA synthesis, and inducing apoptosis.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15601550&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Different cell kinetic changes in rat stomach cancer after treatment with celecoxib or indomethacin: implications on chemoprevention.

Yu J, Tang BD, Leung WK, To KF, Bai AH, Zeng ZR, Ma PK, Go MY, Hu PJ, Sung JJ.

Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China.

AIM: Mechanisms underlying the chemopreventive effects of cyclooxygenase (COX) inhibitors remain elusive. We have previously shown that celecoxib but not indomethacin could prevent carcinogen-induced gastric cancer development in Wistar rats. This chemopreventive effect appeared to be independent of COX-2 and prostaglandin (PG) E2 suppression since the lowest PGE2 was obtained in indomethacin group. This study compared the cell kinetic changes in stomachs of rats after treatment with celecoxib (5, 10, 20 mg/(kg.d)) or indomethacin (3 mg/(kg.d)) to gain more insights into the chemopreventive mechanism. METHODS: The apoptosis and proliferation indexes in gastric tumor, adjacent non-cancer tissues and normal gastric tissues were determined. Apoptosis was quantified by apoptotic nuclei counting and TUNEL, whereas proliferation was determined by Ki67 immunostaining. RESULTS: Treatment with either celecoxib or indomethacin inhibited gastric tumor proliferation by more than 65% (P<0.02). However, celecoxib caused a dose-dependent increase in apoptosis (P<0.05) which was not seen in indomethacin-treated tumors (P = 0.54). The highest apoptosis to proliferation ratio was seen in tumors treated with celecoxib at 10 mg/(kg.d). Treatment with this dose of celecoxib was associated with the lowest incidence of gastric cancer development. CONCLUSION: Our findings suggest that the difference in chemopreventive effects of indomethacin and celecoxib in this animal model of gastric carcinogenesis is largely due to the differential cell kinetic changes, which does not correlate with the degree of COX-2 and PG suppression.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15609394&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Effects and mechanism of the selective COX-2 inhibitor, celecoxib, on rat colitis induced by trinitrobenzene sulfonic acid.

Zhang L, Lu YM, Dong XY.

Department of Gastroenterology, Third Hospital, Peking University, Beijing, China.

OBJECTIVE: To investigate the action of celecoxib (a selective COX-2 inhibitor) in a rat model of colitis induced by trinitrobenzene sulfonic acid (TNBS). METHODS: Rats were randomized into four groups. Colitis was induced in groups 1 and 2 by intracolonic administration of TNBS (25 mg/mL) in 50% ethanol (0.25 mL). The rats in group 1 received oral celecoxib (1.25 mg/kg) and those in group 2 received distilled water (1 mL/0.3 kg), beginning 3 h before induction of colitis and continuing twice daily thereafter for up to 7 days. The rats in group 4 received oral celecoxib (1.25 mg/kg) twice daily for 7 days and those in group 3 were healthy controls. All rats that survived 7 days were killed and both the severity of colonic mucosal damage and the prostaglandin E2 (PGE2) concentrations of the colonic mucosa were assessed. RESULTS: The colonic mucosal damage scores for groups 1 and 2 were 11.15 +/- 3.30 and 8.50 +/- 2.82, respectively, both of which were significantly higher than the score for the healthy controls (0.62 +/- 0.09; P < 0.01, P < 0.01). The score of group 1 was significantly higher than that of group 2 (P < 0.05). No difference was found between the scores of groups 3 and 4. The mucosal concentrations of PGE2 in groups 1 and 2 were 12.00 +/- 4.33 pg/microg and 17.20 +/- 9.62 pg/microg, respectively, both of which were significantly higher than the concentration in the healthy controls (6.02 +/- 3.39 pg/microg; P < 0.05, both). The PGE2 concentration of group 1 was decreased significantly compared with that of group 2 (P < 0.05). No difference was found between groups 3 and 4. CONCLUSION: The results suggest that treatment with celecoxib exacerbates inflammation-associated colonic injury in experimental colitis induced by TNBS. This preliminary study shows that the mechanism is related to suppression by the COX-2 inhibitor of the PG derived from COX-2, but further study is needed to identify if there are other related mechanisms.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15612245&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Celecoxib, a selective cyclooxygenase-2 inhibitor, decreases monocyte chemoattractant protein-1 expression and neointimal hyperplasia in the rabbit atherosclerotic balloon injury model.

Wang K, Tarakji K, Zhou Z, Zhang M, Forudi F, Zhou X, Koki AT, Smith ME, Keller BT, Topol EJ, Lincoff AM, Penn MS.

Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA. wangk ccf.org

The inflammation in response to vascular injury is becoming increasingly recognized as a potential contributor to restenosis. Cyclooxygenase-2 (COX-2) is the inducible form of cyclooxygenase and has been shown to be involved in the proinflammatory response of vascular tissue. Bilateral femoral artery lesions were induced by air desiccation in New Zealand White rabbits followed by high cholesterol diet feeding for 28 days. Balloon injury and stent implantation were performed at the preinjured vessel segments. Immunostaining showed that uninjured vessel segments stained positive only for COX-1 but not for COX-2. Injured vessel segments showed, in addition to COX-1, significant positive staining for COX-2. In the efficacy study, celecoxib (75 mg/kg/d) was administered orally beginning 3 hours before balloon injury or stent implantation on day 28 and daily for 21 days. Monocyte chemoattractant protein-1 (MCP-1) and matrix metalloproteinase-2 and -9 (MMPs) expression were quantified in arterial extracts 4 days after balloon injury by Western blot and gelatin zymography. Morphometric analysis and immunostaining for macrophages were performed 21 days after balloon injury. Celecoxib treatment significantly decreased MCP-1 expression (P < 0.01). Neointimal hyperplasia was significantly inhibited by celecoxib in both balloon injury and stent models (0.49 +/- 0.20 versus 0.70 +/- 0.35 mm2 from balloon injury model, P < 0.05, and 0.81 +/- 0.25 versus 1.69 +/- 0.43 mm2 from stent model, P < 0.05), accompanied by reduced macrophage infiltration. We conclude that celecoxib decreases the inflammatory response and intimal hyperplasia following vascular injury, possibly through inhibition of MCP-1 expression, implying a pivotal role of inflammation in the pathogenesis of restenosis.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15613981&dopt=Abstract celecoxib, Celebrex