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

Wu GS, Zou SQ, Liu ZR, Tang ZH, Wang JH.

Department of General Surgery, Tongji Hospital, 1095 Jiefang Road, Wuhan, 430030, Hubei Province, China. wugaosong9172 sina.com

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.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12800245&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Effects of dexamethasone or celecoxib on biliary toxicity after hepatic arterial infusion of 5-fluorodeoxyuridine in a canine model.

Ensminger W, Knol J, DeRemer S, Wilkinson E, Walker S, Williams D, Maybaum J.

Departments of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0504, USA. ensminge umich.edu

Previous work has shown that in humans the dose-limiting toxicity for fluorodeoxyuridine [2-fluoro-5'-deoxyuridine (FdUrd)] when administered by hepatic arterial infusion is biliary sclerosis. The current study was undertaken to attempt to modify this toxicity in a canine model that has been demonstrated to closely mimic the clinical situation. Unlike previous studies using this model, in which animals were sacrificed after extensive fibrosis had already occurred, the current experiments were designed so that observations of pathology were made at an earlier time, when the initial inflammatory injury underlying the fibrotic process was still taking place. Implantable pumps were used to deliver FdUrd into the hepatic artery of animals at a rate of 0.3 mg/kg/day in the presence or absence of 10 mg/week dexamethasone or 100 mg/day of celecoxib for 35 days, at which time the animals were beginning to show signs of toxicity. After evaluation for radiological evidence of biliary obstruction, the animals were sacrificed and portions of their livers were processed for examination of microscopic pathology and 2-bromo-5'deoxyuridine labeling index. Dexamethasone treatment protected the animals from biliary sclerosis determined radiologically, further validating this model as being representative of the response in humans. Similarly the Cox-2 inhibitor, celecoxib, appeared to provide protection against radiological changes of biliary stricture, although possibly to a lesser degree than the resultant from dexamethasone. In addition, FdUrd treatment caused elevation of the DNA 2-bromo-5'deoxyuridine labeling index above control levels in biliary epithelial cells. Dexamethasone and celecoxib each significantly attenuated the FdUrd-induced elevation of DNA labeling index in biliary epithelium. These findings demonstrate the usefulness of this canine model for studying the mechanisms of drug-induced biliary sclerosis and reinforce the hypothesis that blocking inflammation may retard the progression of injury that eventually leads to fibrosis. This study suggests that clinical testing of celecoxib as a preventive for hepatic arterial-FdUrd induced biliary damage could prove valuable.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14729639&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Cyclooxygenase-2 expression and effect of celecoxib in gastric adenomas of trefoil factor 1-deficient mice.

Saukkonen K, Tomasetto C, Narko K, Rio MC, Ristimaki A.

Department of Pathology, Helsinki University Central Hospital, and Molecular and Cancer Biology Research Program, Biomedicum Helsinki, University of Helsinki, FIN-00014 Helsinki, Finland.

Expression of cyclooxygenase-2 (Cox-2) is elevated in gastric adenocarcinomas and precursor lesions leading to this disease. Mice deficient for trefoil factor 1 (TFF1) develop a pyloric adenoma with full penetrance. Because inhibition of Cox-2 suppresses tumor growth in several animal models, we studied expression of Cox-2 and effect of a selective Cox-2 inhibitor celecoxib in gastrointestinal tissues of the TFF1-deficient mice. Cox-2 mRNA and protein were strongly expressed in the pyloric adenomas of the TFF1(-/-) mice as detected by in situ hybridization and immunohistochemistry. Nonneoplastic gastrointestinal tissues of wild-type or TFF1(-/-) mice expressed low or nondetectable levels of Cox-2. Celecoxib (1600 ppm p.o. for 3 months) caused ulceration and inflammation of the adenoma in all treated TFF1(-/-) mice (n = 7). This effect of the drug was adenoma specific, because no histological alterations were observed in the non-neoplastic gastric or intestinal tissues in the TFF1(-/-) or wild-type mice receiving the drug treatment. All untreated TFF1(-/-) mice had an adenoma (n = 7), but none demonstrated the combination of ulceration and inflammation. Our data show that Cox-2 is expressed in gastric adenomas of the TFF1(-/-) mice and suggest that inhibition of Cox-2 disturbs the integrity of the adenoma by promoting ulceration and inflammation. These findings support the effort to initiate clinical studies to investigate the effect of Cox-2 inhibitors as a chemotherapeutic modality for dysplasias of the stomach.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12810622&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Comparison of the incidence rates of selected gastrointestinal events reported for patients prescribed celecoxib and meloxicam in general practice in England using prescription-event monitoring (PEM) data.

Layton D, Hughes K, Harris S, Shakir SA.

Drug Safety Research Unit, University of Southampton, Southampton, UK. deborah.layton dsru.org

BACKGROUND: Celecoxib and meloxicam are classified as cyclo-oxygenase (COX)-2 selective inhibitors, and were developed to minimize the risk of gastrointestinal (GI) toxicity commonly associated with non-steroidal anti-inflammatory drugs (NSAIDs). The Drug Safety Research Unit (DSRU) monitored the safety of these drugs immediately after launch in England using the non-interventional observational cohort technique of prescription-event monitoring (PEM). Our objective was to investigate whether there is a clinically relevant difference in incidence of reported symptomatic (acid/peptic) and complicated upper GI conditions (perforations/bleeding) between celecoxib and meloxicam during use in general practice. METHODS: Patients were identified from dispensed prescriptions written by general practitioners (GPs) for meloxicam (December 1996 to March 1997) and celecoxib (May to December 2000). Simple questionnaires requesting details of events occurring during/after treatment and potential risk factors (including age, sex, history of upper GI problems, and NSAIDS prescribed within 3 months of treatment) were posted to prescribing GPs at least 6 months after the first prescription for each patient. Incidence rates of the first event were calculated; crude and adjusted rate ratios (RR) obtained using regression modelling. RESULTS: For celecoxib and meloxicam, respectively, 1054 (6.0%) and 1376 (7.2%) patients had symptomatic (acid/peptic) upper GI events whereas 42 (0.2%) and 67 (0.4%) had complicated upper GI conditions (perforations/bleeding). A higher proportion of the celecoxib cohort had an indication for osteoarthritis (28.1 vs 23.2%), were female (68.3 vs 67.1%), were aged 60 yr or more (59.5 vs 55.0%), were prescribed NSAIDs within 3 months of starting treatment (49.4 vs 47.9%), and had a past medical history of upper GI conditions (54.7 vs 29.2%) than those prescribed meloxicam. This suggests differential channelling of groups at higher risk of such events on to celecoxib compared with meloxicam. There was no difference between the two drugs in the time to occurrence of either group of event. The RR over the 270-day study period for celecoxib compared with meloxicam were 0.77 (95% CI 0.69, 0.85) and 0.56 (95% CI 0.32, 0.96) for symptomatic (acid/peptic) upper GI events and complicated upper GI conditions (perforations/bleeding), respectively, adjusted for age, age2, sex, indication, medical history of upper GI problems and whether NSAIDs were prescribed within 3 months prior to starting treatment. CONCLUSIONS: This study reports a relative reduction (23%) in the incidence of symptomatic (acid/peptic) GI events, and a relative reduction (44%) in the incidence rate of complicated upper GI conditions (perforations/bleeding) for celecoxib compared with meloxicam.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12810929&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Intolerance reactions due to the selective cyclooxygenase type II inhibitors rofecoxib and celecoxib. Results of oral provocation tests in patients with NSAID hypersensitivity.

Kruse R, Ruzicka T, Grewe M.

Department of Dermatology, University Hospital Duesseldorf, Duesseldorf, Germany. rkruse uni-duesseldorf.de

Intolerance reactions due to the ingestion of non-steroidal anti-inflammatory drugs (NSAIDs) are frequent emergencies. It is thought that inhibition of the isoenzyme cyclooxygenase type I (COX-1) is responsible for the common NSAID-associated adverse effects, whereas inhibition of COX-2 is mainly responsible for the therapeutic effects. The goal of our study was to estimate the frequency of intolerance reactions due to ingestion of the two newly approved selective COX-2 inhibitors, rofecoxib or celecoxib. In a sample of 13 patients who had previously documented NSAID hypersensitivity reactions to non-selective COX inhibitors, 2 patients (15.3%) showed intolerance reactions (2 of 9 patients with rofecoxib, 1 of 5 patients with celecoxib). These drugs cannot therefore be administered uncritically to patients with known NSAID hypersensitivity. Selective COX-2 inhibitors can only be used as alternative drugs in these patients after assessing their specific tolerability in a properly performed provocation test.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12816152&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Celecoxib activates a novel mitochondrial apoptosis signaling pathway.

Jendrossek V, Handrick R, Belka C.

Department of Radiation Oncology, Experimental Radiotherapy Group, University of Tubingen, Hoppe Seyler Str. 3, D-72076 Tubingen, Germany.

The cyclooxygenase (COX)-2 inhibitor Celecoxib may inhibit cancer cell growth independently of its capacity to block the COX-2 enzyme. The growth inhibitory effect had been attributed to its pro-apoptotic effects. However, the molecular details of Celecoxib-induced apoptosis have not been analyzed yet. To differentiate between death receptor and mitochondrial signaling pathways, induction of apoptosis upon treatment with Celecoxib was tested in Jurkat T- and BJAB B-lymphoma cell lines with defects in either pathway. Celecoxib-induced dose- and time-dependent apoptosis in Jurkat and BJAB cells involving i) activation of caspases-9, -8, and -3, ii) cleavage of poly(ADP-ribose) polymerase and inhibitor of caspase-activated DNAase, iii) breakdown of the mitochondrial membrane potential, and iv) release of cytochrome c. Lack of Fas-associated death domain protein (FADD), overexpression of a dominant negative FADD, lack of caspase-8, and treatment with caspase-8-specific inhibitors had no influence on Celecoxib-induced apoptosis. In contrast, overexpression of a dominant negative caspase-9 or pharmacological inhibition of caspase-9 strongly interfered with Celecoxib-induced cell death. Furthermore, expression of Apaf-1 was required for Celecoxib-induced apoptosis. Importantly, Bcl-2 overexpression did not abrogate caspase activation, mitochondrial alterations, and apoptosis upon Celecoxib treatment while inhibiting radiation induced apoptosis. In conclusion, Celecoxib induces apoptosis via a novel apoptosome-dependent but Bcl-2-independent mitochondrial pathway.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12824303&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Celecoxib but not rofecoxib inhibits the growth of transformed cells in vitro.

Kazanov D, Dvory-Sobol H, Pick M, Liberman E, Strier L, Choen-Noyman E, Deutsch V, Kunik T, Arber N.

Department of Cancer Prevention, Tel Aviv Medical Center, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.

PURPOSE: Nonsteroidal anti-inflammatory drugs reduce the risk of colorectal cancer. The cyclooxygenase (COX) pathway of arachidonic acid metabolism is an important target for nonsteroidal anti-inflammatory drugs. Increased expression of COX-2 was recently shown to be an important step in the multistep process of colorectal cancer carcinogenesis. The new COX-2-specific inhibitors offer the benefit of cancer protection without the gastrointestinal toxicity reported for the old drugs. The purpose of this study was to compare the growth effects of two specific COX-2 inhibitors, celecoxib (Pfizer, Inc., New York, NY), and rofecoxib (Merck, White House Station, NJ) in normal and transformed enterocytes. EXPERIMENTAL DESIGN: Cultures of normal rat intestinal epithelial cell line, IEC-18, vector control cells, c-K-ras, c-K-ras-bak, and antisense-bak derivatives were treated with different dosages of celecoxib (0-60 micro M) and rofecoxib (0-20 micro M). Cell cycle analysis and apoptosis were assessed by fluorescence-activated cell sorting analysis. Protein expression was assessed by Western blot analysis and caspases 3 and 8 activities by ELISA. RESULTS: Celecoxib inhibited cell growth and induced apoptosis in a time- and dose-dependent manner. IEC18 parental cells were two to four times more resistant to celecoxib than ras, ras-bak, and antisense bak transformed cells that overexpress the COX-2 protein. The induction of apoptosis by celecoxib involved the caspase pathways. Rofecoxib, up to its maximal concentration of 20 micro M, did not inhibit cell growth or induce apoptosis. CONCLUSIONS: Celecoxib may prove to be a very efficient component in the prevention and treatment of gastrointestinal tumors because it inhibits the growth of cancerous cells without affecting the growth of normal cells.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14734479&dopt=Abstract celecoxib, Celebrex