celecoxib, Celebrex
Selective cyclooxygenase-2 blocker delays healing of esophageal ulcers in rats and inhibits ulceration-triggered c-Met/hepatocyte growth factor receptor induction and extracellular signal-regulated kinase 2 activation.

Baatar D, Jones MK, Pai R, Kawanaka H, Szabo IL, Moon WS, Kitano S, Tarnawski AS.

Department of Veterans Affairs Medical Center, Long Beach, California 90822, USA.

Nonsteroidal anti-inflammatory drugs, both nonselective and cyclooxygenase-2 (COX-2) selective, delay gastric ulcer healing. Whether they affect esophageal ulcer healing remains unexplored. We studied the effects of the COX-2 selective inhibitor, celecoxib, on esophageal ulcer healing as well as on the cellular and molecular events involved in the healing process. Esophageal ulcers were induced in rats by focal application of acetic acid. Rats with esophageal ulcers were treated intragastrically with either celecoxib (10 mg/kg, once daily) or vehicle for 2 or 4 days. Esophageal ulceration triggered increases in: esophageal epithelial cell proliferation; expression of COX-2 (but not COX-1); hepatocyte growth factor (HGF) and its receptor, c-Met; and activation of extracellular signal-regulated kinase 2 (ERK2). Treatment with celecoxib significantly delayed esophageal ulcer healing and suppressed ulceration-triggered increases in esophageal epithelial cell proliferation, c-Met mRNA and protein expression, and ERK2 activity. In an ex vivo organ-culture system, exogenous HGF significantly increased ERK2 phosphorylation levels in esophageal mucosa. A structural analog of celecoxib, SC-236, completely prevented this effect. These findings indicate that celecoxib delays esophageal ulcer healing by reducing ulceration-induced esophageal epithelial cell proliferation. These actions are associated with, and likely mediated by, down-regulation of the HGF/c-Met-ERK2 signaling pathway.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11891194&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Lamin B, caspase-3 activity, and apoptosis induction by a combination of HMG-CoA reductase inhibitor and COX-2 inhibitors: a novel approach in developing effective chemopreventive regimens.

Swamy MV, Cooma I, Reddy BS, Rao CV.

Chemoprevention Program, Division of Nutritional Carcinogenesis, American Health Foundation, Valhalla, NY 10595, USA.

Apoptosis plays a central role in tumor development and it has been hypothesized that lack/failure of apoptosis leads to the development of tumors, including colon tumors. Thus, induction of apoptosis in tumor cells is an effective approach to the regulation of tumor growth. It has been shown by us and other investigators that various chemopreventive agents induce apoptosis and inhibit tumor growth. Identification of agents or combinations of agents that induce tumor cell apoptosis guides the development of novel agents for colon cancer treatment. Experiments were designed to assess the effectiveness of lovastatin, a 3-hydroxy-3-methyl glutaryl-CoA reductase inhibitor, and celecoxib a cyclooxygenase-2 inhibitor, individually or in combination on the induction of apoptosis in human HT-29 colon cancer cells. In addition, we studied the modulatory effect of lovastatin and celecoxib on lamin B levels, caspase-3 activity and expression in relationship to apoptosis in colon cancer cell lines. HT-29 cells exposed to various subtoxic levels of lovastatin or celecoxib or a combination of both were analyzed for apoptosis (by DAPI method), caspase-3 expression (immunoblot analysis) and caspase-3 activity (fluorimetric method). We found that: i) pretreatment with lovastatin (5-30 microM) induces apoptosis in HT-29 cells significantly only at high concentrations (> or = 20 microM) but not at low dose levels; ii) similarly, pretreatment with celecoxib produced apoptosis in colon cancer cells at high concentrations only (> or = 75 microM); iii) caspase-3 protein expression was moderately altered by the treatment with lovastatin or celecoxib at lower concentrations; however, a significant increase (1.6 to 4-fold) in caspase-3 expression and activity was found in HT-29 cells exposed with 20-25 microM lovastatin and/or 5-125 microM celecoxib and iv) importantly, in tumor cells exposed to low doses of (5 or 10 microM) lovastatin, combined with 25-75 microM of celecoxib, apoptosis induction rose 2.5 to 10-fold, caspase-3 expression was 2.3 to 8-fold higher, and enzyme activities were 1.5 to 5.5-fold elevated. This effect was highly synergistic and dose-dependent. Lamin B levels were significantly increased in a dose-dependent manner in cells treated with lovastatin but no such effect was observed with celecoxib. These results indicate that agents with different modes of action when applied in combinations will induce apoptosis synergistically by enhancing caspase-3 activities. These findings further support the hypothesis that HMGCo-R and COX-2 activities play important roles in apoptosis and regulation of apoptosis by selective agents such as lovastatin and celecoxib would provide effective strategies for the prevention of colon cancer.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11894121&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Effect of celecoxib on Ca2+ movement and cell proliferation in human osteoblasts.

Wang JL, Lin KL, Chen JS, Lu YC, Jiann BP, Chang HT, Hsu SS, Chen WC, Huang JK, Ho CM, Jan CR.

Department of Rehabilitation, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan, ROC.

In human osteoblasts, the effect of the widely prescribed cyclooxygenase-2 inhibitor celecoxib on intracellular Ca(2+) concentrations ([Ca(2+)](i)) and cell proliferation was explored by using fura-2 and the tetrazolium assay, respectively. Celecoxib at concentrations greater than 1microM caused a rapid rise in [Ca(2+)](i) in a concentration-dependent manner ( EC 50= 10 microM). Celecoxib-induced [Ca(2+)](i) rise was reduced by 90% by removal of extracellular Ca(2+), and by 30% by l-type Ca(2+) channel blockers. Celecoxib-induced Mn(2+)-associated quench of intracellular fura-2 fluorescence also suggests that celecoxib-induced extracellular Ca(2+) influx. In Ca(2+)-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+)-ATPase, caused a monophasic [Ca(2+)](i) rise, after which the increasing effect of celecoxib on [Ca(2+)](i) was greatly inhibited. Conversely, pretreatment with celecoxib to deplete intracellular Ca(2+) stores totally prevented thapsigargin from releasing more Ca(2+). U73122, an inhibitor of phoispholipase C, abolished histamine (an inositol 1,4,5-trisphosphate-dependent Ca(2+) mobilizer)-induced, but not celecoxib-induced, [Ca(2+)](i) rise. Pretreatment with phorbol 12-myristate 13-acetate and forskolin to activate protein kinase C and adenylate cyclase, respectively, partly inhibited celecoxib-induced [Ca(2+)](i) rise in Ca(2+)-containing medium. Separately, overnight treatment with 1-100microM celecoxib inhibited cell proliferation in a concentration-dependent manner. These findings suggest that in human osteoblasts, celecoxib increases [Ca(2+)](i) by stimulating extracellular Ca(2+) influx and also by causing intracellular Ca(2+) release from the endoplasmic reticulum via a phospholiase C-independent manner. Celecoxib may be cytotoxic at higher concentrations.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15006548&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Identification of sulfonamide-like adverse drug reactions to celecoxib in the World Health Organization database.

Wiholm BE.

Department of Clinical Pharmacology, Huddinge University Hospital, Stockholm, Sweden. Bengt-Erik.Wilholm labtek.ki.se

BACKGROUND: The selective COX-2 inhibitor celecoxib has a sulfonamide structure and is contraindicated for patients with known sulfa allergy. However, there is currently no standard available for the identification of sulfonamide-related adverse drug reactions (ADRs) and the occurrence of such ADRs with celecoxib has not been established. THE AIMS OF THIS STUDY WERE: (1) to identify the typical pattern of sulfonamide ADRs from literature and verify this pattern in the World Health Organization (WHO) ADR database; and (2) to examine whether these sulfonamide ADRs occur more frequently with celecoxib than with the non-sulfonamide, COX-2 inhibitor rofecoxib. METHODS: A sulfonamide ADR pattern was derived from the most extensive textbook source of ADRs and applied to the WHO database for the three groups of sulfonamide drugs: short- and intermediate-acting sulfonamides, and sulfasalazine. ADRs reported three or more times for each of these groups were included in a 'sulfonamide template' comprising 19 ADRs relating to the skin, the blood, the liver, and anaphylaxis. This template was then applied to celecoxib and rofecoxib. RESULTS: Overall, the relative reporting rate of a sulfonamide-type ADR with celecoxib was 80% higher than with rofecoxib, whether this was based on total number of reports (RR 1.8, 95% Cl 1.6-1.9) or restricted to reports that listed coxibs as the sole suspected drugs (RR 1.8, 95% Cl 1.6-1.9). There were numerically more ADRs for celecoxib than for rofecoxib in 15 of the 19 terms. Within the ADRs in the sulfonamide template, relative reporting rate of fatal reactions was 80% higher with celecoxib (RR 1.8, 95% Cl 0.9-4.0). Even though serious sulfonamide reactions are rare, their clinical impact on patient safety warrants close monitoring as more data becomes available. Physicians should be aware of possible sulfonamide allergy when prescribing celecoxib.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11900314&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Overexpression of cyclooxygenase-2 (COX-2) in human primitive neuroectodermal tumors: effect of celecoxib and rofecoxib.

Patti R, Gumired K, Reddanna P, Sutton LN, Phillips PC, Reddy CD.

Division of Neuro-Oncology, Joseph Stokes Research Institute #515G, 3516 Civic Center Blvd, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.

In this study the role of cyclooxygenase-2 (COX-2) in primitive neuroectodermal tumor (PNET) the most malignant brain tumors of childhood was investigated. COX-2 expression in human brain tumor biopsy samples (seven/seven) was about 6-8-fold higher than normal brain tissue and several PNET cell lines also express COX-2. The effect of selective COX-2 inhibitors, celecoxib and rofecoxib on the growth of two PNET cell lines (DAOY and PFSK) was determined. Celecoxib was more potent than rofecoxib in suppressing cell growth. Growth inhibition by celecoxib and rofecoxib was independent of Bcl-2 expression. Celecoxib suppressed the expression of Akt and activated the caspase-3 in DAOY and PFSK, whereas rofecoxib did not have such an effect.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11911965&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Celecoxib exhibits the greatest potency amongst cyclooxygenase (COX) inhibitors for growth inhibition of COX-2-negative hematopoietic and epithelial cell lines.

Waskewich C, Blumenthal RD, Li H, Stein R, Goldenberg DM, Burton J.

Garden State Cancer Center, Belleville, New Jersey 07109, USA.

Cyclooxygenase-2 (COX-2) is an important cellular target for both therapy and/or prevention of inflammatory disorders and cancer. The advent of selective COX-2 inhibitors now allows a more precise and safer treatment approach. The screening of an array of cancer cell lines for growth inhibitory effects of COX-2-selective and -nonselective inhibitors, including celecoxib (Celebrex) and rofecoxib (Vioxx), produced two unanticipated findings. Firstly, the antiproliferative effects of celecoxib were noted to be of very similar magnitude for both hematopoietic and epithelial cancer cell lines. Most hematopoietic cell lines had no detectable COX-2 expression by reverse transcription-PCR, and none expressed COX-2 protein. In addition, COX-2-negative epithelial lines were found to have IC50s for celecoxib that were very similar to their COX-2+ counterparts. Thus, important antiproliferative effects were observed that were independent of both the cell lineage and COX-2 status. Secondly, it was also observed that COX-2 inhibitor drugs, celecoxib and rofecoxib, with similar COX-2-selectivity and clinical efficacy for inflammatory indications, differed significantly in their in vitro antiproliferative effects on cancer cell lines. IC50s of 35-65 microM were observed for celecoxib across this entire panel of cell lines. Finally, no difference in the mode or degree of cytotoxicity was apparent between cell lines, because similar levels of apoptosis were observed in COX-2+ and -negative cell lines after treatment with celecoxib, with correspondingly lower levels after rofecoxib treatment. These data are important in that they provide the first direct comparison of epithelial and hematopoietic cancer cell lines, as well as a direct comparison of the in vitro anticancer effects of the two clinically available COX-2 inhibitors.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11929821&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Selective inhibition of COX-2 is beneficial to mice infected intranasally with VSV.

Chen N, Restivo A, Reiss CS.

Department of Biology, New York University, NY 10003, USA.

Cyclooxygenase (COX) is the key enzyme for prostaglandin (PG) synthesis. PGs are mediators of many critical physiological and inflammatory responses. There are two isoforms, COX-1 and COX-2, both of which are constitutively expressed in the central nervous system (CNS). Studies have shown that COX-1 and COX-2 are involved in physiological and pathological conditions of the brain. However, little is known about the role(s) of COX in the host defense system against a viral infection in the CNS. In this report, we used Vesicular Stomatitis Virus (VSV) induced acute encephalitis to distinguish between the contribution(s) of the two isoforms. COX-2 activity was inhibited with a COX-2 selective drug, celecoxib (Celebrex), and COX-1 was antagonized with SC560. We found that inhibition of COX-2 led to decreased viral titers, while COX-1 antagonism did not have the same effect at day 1 post infection. 5-lipooxygenase (5-LO) expression and neutrophil recruitment in the CNS were increased in celecoxib-inhibited mice. Furthermore, mice treated with celecoxib expressed more Nitric Oxide Synthase-1 (NOS-1), a crucial component of the innate immune system in the restriction of VSV propagation. The expression of type 1 cytokines, IFN-gamma and IL-12, were also increased in celecoxib-treated mice.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11936620&dopt=Abstract celecoxib, Celebrex