celecoxib, Celebrex
Celecoxib incorporated chitosan microspheres: in vitro and in vivo evaluation.

Thakkar H, Sharma RK, Mishra AK, Chuttani K, Murthy RS.

New Drug Delivery System Laboratory, Pharmacy Department, Donor's Plaza, Opp. To University main office, M.S University of Baroda, Fatehgunj, Vadodara 390 002, India.

Recently, considerable interest has been focussed on the use of biodegradable polymers for specialized applications such as controlled release of drug formulations; meanwhile, microsphere drug delivery systems using various kinds of biodegradable polymers have been studied extensively during the past two decades. In the present investigation, it was aimed to prepare microsphere formulations of celecoxib using a natural polymer, chitosan as a carrier for intra-articular administration to extend the retention of the drug in the knee joint. Microsphere formulations were evaluated in vitro for particle size, entrapment efficiency, surface morphology and in vitro drug release. For in vivo studies, (99m)Technetium- labeled glutathione was used as a radiopharmaceutical to demonstrate arthritic lesions by gamma scintigraphy. Evaluation of arthritic lesions post therapy in rats showed a significant difference (P < 0.005) in the group treated with celecoxib solution compared to the group treated with celecoxib loaded chitosan microspheres.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15621680&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
The selective cyclooxygenase-2 inhibitor celecoxib modulates the formation of vasoconstrictor eicosanoids and activates PPARgamma. Influence of albumin.

Lopez-Parra M, Claria J, Titos E, Planaguma A, Parrizas M, Masferrer JL, Jimenez W, Arroyo V, Rivera F, Rodes J.

DNA Unit, Hospital Clinic, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Villarroel 170, Barcelona 08036, Spain.

BACKGROUND/AIMS: Selective cyclooxygenase (COX)-2 inhibitors do not adversely affect renal function in experimental cirrhosis. In the current study, we investigated the molecular mechanisms underlying the effects of the selective COX-2 inhibitor, celecoxib, and assessed the influence of albumin on its actions. METHODS: Rat mesangial cells (RMC) were incubated with celecoxib in the absence or presence of albumin, and levels of selected vasoconstrictor eicosanoids, renin release and alpha-smooth muscle actin (alpha-SMA) expression were determined. The effects of celecoxib on PPARgamma were assessed in RMC co-transfected with PPARgamma and luciferase reporter constructs. RESULTS: Under resting conditions, RMC expressed COX-1, COX-2 and 12/15-lipoxygenase and mainly generated prostaglandin (PG)E2, thromboxane (TX)B2, 12-hydroxyeicosatetraenoic acid (12-HETE) and 8-epi-PGF2alpha. Celecoxib, in addition to reducing PGE2, significantly decreased 8-epi-PGF2alpha formation. In the presence of albumin, celecoxib also reduced TXB2 and 12-HETE. Albumin per se inhibited PGE2 as well as renin release. In trans-activation assays, celecoxib acted as a PPARgamma agonist whereas albumin inhibited PPARgamma as well as 15d-PGJ2-induced PPARgamma activation. Finally, celecoxib and albumin potentiated the inhibitory effect of 15d-PGJ2 on alpha-SMA expression. CONCLUSIONS: These data provide novel molecular mechanisms of celecoxib and their modulation by albumin, that may be relevant to prevent renal dysfunction in conditions of unbalanced effective blood volume.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15629510&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Selective COX-2 Inhibitors and Renal Injury in Salt-Sensitive Hypertension.

Hermann M, Shaw S, Kiss E, Camici G, Buhler N, Chenevard R, Luscher TF, Grone HJ, Ruschitzka F.

FESC, Cardiology, University Hospital Zurich, 8091 Zurich, Switzerland. frank.ruschitzka usz.ch.

In view of the ongoing controversy of cardiorenal safety of selective COX-2 inhibitors (coxibs), the present study was designed to examine the effects of 2 different coxibs, celecoxib and rofecoxib, compared with a traditional NSAID, diclofenac, and placebo on renal morphology and function in salt-sensitive hypertension. Salt-sensitive (DS) and salt-resistant (DR) Dahl rats were fed with NaCl-enriched diet (4% NaCl) for 8 weeks. Diclofenac (DS-diclofenac), rofecoxib (DS-rofecoxib), celecoxib (DS-celecoxib), or placebo was added to chow from weeks 6 to 8. Immunostaining for monocytes/macrophages (ED1) and cytotoxic T lymphocytes (CD8) was performed. In addition, renal morphology and proteinuria were assessed. Renal cortex mRNA was isolated for determination of COX-2, eNOS, and CRP mRNA by real-time reverse-transcriptase polymerase chain reaction. Untreated hypertensive animals showed glomerular injury including collapsing glomerulopathy, mesangial sclerosis, mesangiolysis, extracapillary proliferation, protein drops, and an especially high grade of glomerulosclerosis (P<0.05 versus DR-placebo) and CD8-positive and ED1-positive cells (P<0.01 versus DR-placebo), which was improved by celecoxib but not by diclofenac and rofecoxib. C-reactive protein mRNA in renal cortex was increased in DS-placebo animals (P<0.05 versus DR-placebo) and normalized by celecoxib (P<0.05 versus DS-placebo), whereas eNOS mRNA was decreased in the DS-rofecoxib group (P<0.05 versus DR-placebo, DS-celecoxib, and DS-diclofenac). Proteinuria was observed in hypertensive animals (P<0.0001 versus DR-placebo), increased by rofecoxib (P<0.05 versus DS-placebo), and normalized by celecoxib (P=0.0015 versus DS-placebo). This head-to-head comparison of selective and nonselective COX inhibitors demonstrates differential effects of coxibs on renal morphology and function in salt-dependent hypertension.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15630049&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Cyclooxygenase-2 specific inhibitors and upper gastrointestinal tolerability in patients with osteoarthritis receiving concomitant low dose aspirin: pooled analysis of 2 trials.

Goldstein JL, Bello AE, Spalding W, Suh S, Fort JG.

Section of Digestive and Liver Diseases, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612-7323, USA. jlgoldst uic.edu

OBJECTIVE: To evaluate the relative gastrointestinal (GI) tolerability of celecoxib and rofecoxib in elderly hypertensive patients with osteoarthritis (OA) with or without coadministration of low dose aspirin (ASA) (< or = 325 mg daily). METHODS: Two independently conducted, multicenter, double blind, randomized controlled trials designed to evaluate GI tolerability, in addition to cardiorenal study endpoints, in patients randomized to celecoxib 200 mg once daily (qd; n = 960) or rofecoxib 25 mg qd (n = 942) were analyzed. GI tolerability was assessed using investigator-reported GI symptoms, prespecified as abdominal pain, dyspepsia, and nausea. The pooled incidences of the 3 reported GI symptoms, regardless of severity (mild and moderate to severe), and the incidences of mild or moderate to severe GI symptoms individually were evaluated. RESULTS: In the pooled population, the incidence of the 3 GI symptoms, regardless of severity, was not significantly different for patients receiving celecoxib or rofecoxib. In contrast, the aggregate incidence of moderate to severe GI symptoms for patients receiving rofecoxib (5.2%) was significantly greater than for those receiving celecoxib (3.2%; p < 0.05). Notably, the significant difference between the 2 arms was more pronounced in the population of patients receiving concomitant low dose ASA (rofecoxib 9.7% vs celecoxib 1.5%; p < 0.001). The incidence of moderate to severe GI symptoms was similar with rofecoxib (3.3%) and celecoxib (3.9%; p = 0.564) treatment in patients who did not receive low dose ASA. CONCLUSION: While the GI tolerability was similar in the 2 arms of the entire pooled population, celecoxib 200 mg qd was associated with a significantly lower incidence of moderate to severe GI symptoms than rofecoxib 25 mg qd in patients receiving concomitant low dose ASA.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15630735&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Increased cyclooxygenase-2 (COX-2): a potential role in the pathogenesis of lymphoma.

Wun T, McKnight H, Tuscano JM.

Department of Internal Medicine, Division of Hematology and Oncology, UC Davis Cancer Center, University of California, 4501 X Street, Sacramento, CA 95817, USA.

B cell lymphomas are a diverse group of clinicopathologic diseases with an increasing incidence. As with other malignancies, the accumulation of genetic abnormalities are required for malignant transformation of human lymphocytes. Cyclooxygenase-2 (COX-2) is a key biosynthetic enzyme in prostaglandin synthesis and has been implicated in the pathogenesis of numerous malignancies including colon, breast, and lung cancer. There is little data on the potential role of COX-2 in lymphoma pathogenesis. In this study, several B lymphoma cell lines and primary B cells obtained from normal volunteer controls were examined for COX-2 protein expression. Immunoblot analysis demonstrated between an approximately 2.2-4.3-fold increase in COX-2 protein expression relative to primary B cells in all lymphoma cell lines examined. Increased COX-2 phosphorylation was found in the BJAB, BL41, and Raji cells whereas the levels in Daudi, Namalwa, and Ramos did not differ from that of primary B cells. Treatment with 25-100 microM celecoxib (CEL) resulted in decreased proliferation as measured by [3H]thymidine in all cell lines examined, and the effect was dose-dependent, and not significantly enhanced by chlorambucil (CHL). The effect of COX-2 inhibition on apoptosis in lymphoma cells was examined and revealed apoptotic induction of greater than 85% in all cell lines examined at 50 microM celecoxib. The pro-apoptotic effect was dose-dependent, and was not significantly enhanced by chlorambucil. Examination of apoptosis-related proteins by immunoblot analysis revealed levels of BCL-2, BCL-X(L), and Bax to be unaffected by celecoxib. In contrast, levels of Akt, MCL-1, and phosphorylated SAP-kinase were all decreased after incubation with 50 microM celecoxib. These findings suggest that increased COX-2 expression and activity, contributes to the pathogenesis of B cell lymphomas and point to a possible role for COX-2 inhibition in their treatment.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14654083&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Survivin: a novel target for indomethacin-induced gastric injury.

Chiou SK, Tanigawa T, Akahoshi T, Abdelkarim B, Jones MK, Tarnawski AS.

Department of Medicine, Gastroenterology Section, Veterans Affairs Medical Center, 5901 East 7th Street, Long Beach, CA 90822, USA. skchiou yahoo.com

BACKGROUND & AIMS: Nonsteroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal erosions and ulcers. Apoptosis is one of the mechanisms. The role of survivin, an antiapoptosis protein, in NSAID-induced gastric injury is unknown. We examined the role of survivin in NSAID-induced gastric mucosal and gastric cell injury. METHODS: We examined: (1) the effects of indomethacin (nonselective NSAID), celecoxib and NS-398 (cyclooxygenase [COX]-2-selective NSAIDs), SC-560 (a COX-1-selective NSAID), and SC-560 plus celecoxib on survivin expression and extent of injury in rat gastric mucosa; (2) the effects of indomethacin, NS-398, SC-560, and SC-560 plus NS-398 on survivin expression and injury in gastric epithelial (RGM-1) cells; and (3) the effects of survivin suppression with small interfering RNA (siRNA) on RGM-1 cell integrity at baseline and following indomethacin injury. RESULTS: Indomethacin treatment dose-dependently reduced survivin protein levels and caused severe injury of gastric mucosa and RGM-1 cells. Suppression of survivin expression with siRNA in RGM-1 cells caused cell damage and increased susceptibility to injury by indomethacin. Celecoxib treatment caused exfoliation of the mucosal surface epithelium, but neither caused deep erosions or altered survivin expression. Neither NS-398 nor SC-560 treatment altered survivin levels or produced injury in vivo or in vitro. COX-1 and COX-2 inhibitor combination caused injury in vivo and in vitro but did not decrease survivin expression. CONCLUSIONS: (1) Indomethacin, but not selective COX-1 or COX-2 inhibitors alone or in combination, reduces survivin expression in gastric mucosal cells and (2) significant reduction of survivin precedes greater severity of gastric injury.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15633124&dopt=Abstract celecoxib, Celebrex



celecoxib, Celebrex
Growth inhibitory effects of celecoxib in human umbilical vein endothelial cells are mediated through G1 arrest via multiple signaling mechanisms.

Lin HP, Kulp SK, Tseng PH, Yang YT, Yang CC, Chen CS, Chen CS.

Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210-1291, USA.

Evidence suggests that the angiogenic endothelium represents an important target through which celecoxib mediates in vivo antitumor effects. Nevertheless, the pharmacologic basis for celecoxib-caused growth inhibition in endothelial cells in vitro remains to be defined. Previously, we showed that celecoxib-induced apoptosis in PC-3 prostate cancer cells was mediated in part through the inhibition of 3-phosphoinositide-dependent kinase-1/Akt signaling. Our present findings show that celecoxib inhibits the growth of human umbilical vein endothelial cells (HUVEC) with pharmacologic profiles reminiscent of those of PC-3 cells. The underlying antiproliferative mechanism, however, may differ between these two cell types considering differences in the functional status of many tumor suppressors, including PTEN, p53, and retinoblastoma, all of which play integral roles in regulating cell cycle progression and survival. From a mechanistic perspective, the genomic integrity of the HUVEC system presents a vastly different intracellular context to examine how celecoxib acts to induce growth inhibition. Here, we obtain evidence that the antiproliferative effects of celecoxib and its close, cyclooxygenase-2-inactive analogue 4-[5-(2,5-dimethylphenyl)-3(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (DMC) in HUVECs at pharmacologically attainable concentrations (10-20 micromol/L) are attributable to the inhibition of phosphoinositide-dependent kinase-1/Akt signaling and cyclin-dependent kinase. Especially, celecoxib- and DMC-mediated G1 arrest is associated with attenuated retinoblastoma phosphorylation through the inhibition of multiple cyclin-dependent kinases (IC50, 10-35 micromol/L). Moreover, both celecoxib and DMC reduce neovascularization in the chicken chorioallantoic membrane assay, suggesting the involvement of a cyclooxygenase-2-independent mechanism in the in vivo antiangiogenic effects of celecoxib.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15634661&dopt=Abstract celecoxib, Celebrex