Structure of the mitogen-inducible TIS10 gene and demonstration that the TIS10-encoded protein is a functional prostaglandin G/H synthase

The Presence of TGFβ3 in Human Ovarian Intrafollicular Fluid and Its Involvement in Thromboxane Generation in Follicular Granulosa Cells through a Canonical TGFβRI, Smad2/3 Signaling Pathway and COX-2 Induction

Ovarian follicular fluid (FF) has a direct impact on oocyte quality, playing key roles in fertilization, implantation, and early embryo development. In our recent study, we found FF thromboxane (TX) to be a novel factor inversely correlated with oocyte maturation and identified thrombin, transforming growth factor β (TGFβ), TNF-α, and follicular granulosa cells (GCs) as possible contributors to FF TX production. Therefore, this study sought to investigate the role of TGFβ3 in regulating TX generation in human ovarian follicular GCs. TGFβ3 was differentially and significantly present in the FF of large and small follicles obtained from IVF patients with average concentrations of 68.58 ± 12.38 and 112.55 ± 14.82 pg/mL, respectively, and its levels were correlated with oocyte maturity. In an in vitro study, TGFβ3 induced TX generation/secretion and the converting enzyme-COX-2 protein/mRNA expression both in human HO23 and primary cultured ovarian follicular GCs. While TGFβRI and Smad2/3 signaling was mainly required for COX-2 induction, ERK1/2 appeared to regulate TX secretion. The participation of Smad2/3 and COX-2 in TGFβ3-induced TX generation/secretion could be further supported by the observations that Smad2/3 phosphorylation and nuclear translocation and siRNA knockdown of COX-2 expression compromised TX secretion in GCs challenged with TGFβ3. Taken together, the results presented here first demonstrated that FF TGFβ3 levels differ significantly in IVF patients' large preovulatory and small mid-antral follicles and are positively associated with oocyte maturation. TGFβ3 can provoke TX generation by induction of COX-2 mRNA/protein via a TGFβR-related canonical Smad2/3 signaling pathway, and TX secretion possibly by ERK1/2. These imply that TGFβ3 is one of the inducers for yielding FF TX in vivo, which may play a role in folliculogenesis and oocyte maturation.

An Aspirin a Day: New Pharmacological Developments and Cancer Chemoprevention

Chemoprevention refers to the use of natural or synthetic agents to reverse, suppress, or prevent the progression or recurrence of cancer. A large body of preclinical and clinical data suggest the ability of aspirin to prevent precursor lesions and cancers, but much of the clinical data are inferential and based on descriptive epidemiology, case control, and cohort studies or studies designed to answer other questions (e.g., cardiovascular mortality). Multiple pharmacological, clinical, and epidemiologic studies suggest that aspirin can prevent certain cancers but may also cause other effects depending on the tissue or disease and organ site in question. The best-known biological targets of aspirin are cyclooxygenases, which drive a wide variety of functions, including hemostasis, inflammation, and immune modulation. Newly recognized molecular and cellular interactions suggest additional modifiable functional targets, and the existence of consensus molecular cancer subtypes suggests that aspirin may have differential effects based on tumor heterogeneity. This review focuses on new pharmacological developments and innovations in biopharmacology that clarify the potential role of aspirin in cancer chemoprevention.

Discovery of a Redox-Activatable Chemical Probe for Detection of Cyclooxygenase-2 in Cells and Animals

Cyclooxygenase-2 (COX-2) expression is up-regulated in inflammatory tissues and many premalignant and malignant tumors. Assessment of COX-2 protein in vivo, therefore, promises to be a powerful strategy to distinguish pathologic cells from normal cells in a complex disease setting. Herein, we report the first redox-activatable COX-2 probe, fluorocoxib Q (FQ), for in vivo molecular imaging of pathogenesis. FQ inhibits COX-2 selectively in purified enzyme and cell-based assays. FQ exhibits extremely low fluorescence and displays time- and concentration-dependent fluorescence enhancement upon exposure to a redox environment. FQ enters the cells freely and binds to the COX-2 enzyme. FQ exhibits high circulation half-life and metabolic stability sufficient for target site accumulation and demonstrates COX-2-targeted uptake and retention in cancer cells and pathologic tissues. Once taken up, it undergoes redox-mediated transformation into a fluorescent compound fluorocoxib Q-H that results in high signal-to-noise contrast and differentiates pathologic tissues from non-pathologic tissues for real-time in vivo imaging.

Specialized Pro-resolving Mediators Reduce Pro-nociceptive Inflammatory Mediator Production in Models of Localized Provoked Vulvodynia

Localized provoked vulvodynia (LPV) is the most common cause of chronic dyspareunia in premenopausal women, characterized by pain with light touch to the vulvar vestibule surrounding the vaginal opening. The devastating impact of LPV includes sexual dysfunction, infertility, depression, and even suicide. Yet, its etiology is unclear. No effective medical therapy exists; surgical removal of the painful vestibule is the last resort. In LPV, the vestibule expresses a unique inflammatory profile with elevated levels of pro-nociceptive proinflammatory mediators prostaglandin E2 (PGE2) and interleukin-6 (IL-6), which are linked to lower mechanical sensitivity thresholds. Specialized pro-resolving mediators (SPMs), lipids produced endogenously within the body, hold promise as an LPV treatment by resolving inflammation without impairing host defense. Ten of 13 commercially available SPMs reduced IL-6 and PGE2 production by vulvar fibroblasts, administered either before or after inflammatory stimulation. Using a murine vulvar pain model, coupling proinflammatory mediator quantification with mechanical sensitivity threshold determination, topical treatment with the SPM, maresin 1, decreased sensitivity and suppressed PGE2 levels. Docosahexaenoic acid, a precursor of maresin 1, was also effective in reducing PGE2 in vulvar fibroblasts and rapidly restored mouse sensitivity thresholds. Overall, SPMs and their precursors may be a safe and efficacious for LPV. Perspective: Vulvodynia, like many pain conditions, is difficult to treat because disease origins are incompletely understood. Here, we applied our knowledge of more recently discovered vulvodynia disease mechanisms to screen novel therapeutics. We identified several specialized pro-resolving mediators as likely potent and safe for treating LPV with potential for broader application.

AHR Signaling Interacting with Nutritional Factors Regulating the Expression of Markers in Vascular Inflammation and Atherogenesis

There is strong evidence that exposure to fine particulate matter (PM_2.5) and a high-fat diet (HFD) increase the risk of mortality from atherosclerotic cardiovascular diseases. Recent studies indicate that PM_2.5 generated by combustion activates the Aryl Hydrocarbon Receptor (AHR) and inflammatory cytokines contributing to PM_2.5-mediated atherogenesis. Here we investigate the effects of components of a HFD on PM-mediated activation of AHR in macrophages. Cells were treated with components of a HFD and AHR-activating PM and the expression of biomarkers of vascular inflammation was analyzed. The results show that glucose and triglyceride increase AHR-activity and PM_2.5-mediated induction of cytochrome P450 (CYP)1A1 mRNA in macrophages. Cholesterol, fructose, and palmitic acid increased the PM- and AHR-mediated induction of proinflammatory cytokines in macrophages. Treatment with palmitic acid significantly increased the expression of inflammatory cytokines and markers of vascular injury in human aortic endothelial cells (HAEC) after treatment with PM_2.5. The PM_2.5-mediated activation of the atherogenic markers C-reactive protein (CRP) and S100A9, a damage-associated molecular pattern molecule, was found to be AHR-dependent and involved protein kinase A (PKA) and a CCAAT/enhancer-binding protein (C/EBP) binding element. This study identified nutritional factors interacting with AHR signaling and contributing to PM_2.5-induced markers of atherogenesis and future cardiovascular risk.

ALK3-SMAD1/5 Signaling Mediates the BMP2-Induced Decrease in PGE2 Production in Human Endometrial Stromal Cells and Decidual Stromal Cells

BMP2 is a critical factor that is involved in the processes of embryo implantation and uterine decidualization. The expression of cyclooxygenase (COX) and subsequent prostaglandin E2 (PGE2) production are critical for successful pregnancy. However, it is not clear whether BMP2 can regulate the production of PG during endometrial decidualization. The aim of this study was to investigate the effects of BMP2 on COX-1 expression and PGE2 production as well as the underlying molecular mechanisms in the human endometrium. Immortalized human endometrial stromal cells (HESCs) and human decidual stromal cells (HDSCs) were used as the study model to investigate the effects of BMP2-induced cellular activities. Our results showed that BMP2 treatment significantly decreased PGE2 production by downregulating COX-1 expression in both human endometrial stromal and decidual stromal cells. Additionally, BMP2 induced an increase in the levels of phosphorylated SMAD1/5/8, and this effect was completely abolished by the addition of the inhibitors DMH-1 and dorsomorphin, but not by SB431542. Knocking down ALK3 completely reversed the BMP2-induced downregulation of COX-1. Moreover, concomitantly knocking down SMAD1 and SMAD5 completely reversed the BMP2-induced downregulation of COX-1. Our results indicated that BMP2 decreased PGE2 production by downregulating COX-1 expression, most likely through the ALK3/SMAD1-SMAD5 signaling pathway in human endometrial stromal and human decidual stromal cells. These findings deepen our understanding of the functional role of BMP2 in the regulation of endometrial decidualization in humans.

Glucagon-Like Peptide 1 Attenuates Lipotoxicity-Induced Islet Dysfunction in ApoE-/- Mice

AIM

Glucagon-like peptide-1 (GLP1) is known to decrease glucagon release and may be beneficial for the reduction of elevated blood glucose. However, its role and mechanism of action in diabetes remain elusive. This study aimed to examine the function of GLP1 and analyze the mechanism of effect that GLP1exerts on inducible nitric oxide synthase (iNOS) in diabetic mice.

METHODS

A diabetes model was established in ApoE-/- mice fed a high-fat diet and treated with GLP1 and/or lentivirus-expressing PARP1. PARP1, iNOS, and inflammatory factors in islets were detected by Western blot and ELISA. Islet α cells and β cells and CD8+ T lymphocytes were detected by immunostaining. Islet-cell apoptosis was detected by TUNEL.

RESULTS

GLP1 inhibited the expression of PARP1 and iNOS in islets, alleviated decrease in β cells, and suppressed cell apoptosis induced by the high-fat diet. Moreover, GLP1 recovered the decline in insulin sensitivity and glucose tolerance in ApoE-/- mice fed the high-fat diet, and the effects of GLP1 were related to the inhibition of COX2 and NFκB expression.

CONCLUSION

GLP1 significantly alleviated the decrease in β-cell numbers, suppressed β-cell apoptosis induced by the high-fat diet, inhibited the expression of iNOS, and alleviated inflammatory islet injury via inhibiting the COX2-NFκB pathway.

A Protective Role of Aryl Hydrocarbon Receptor Repressor in Inflammation and Tumor Growth

The aryl hydrocarbon receptor (AhR) is known for mediating the toxicity of environmental pollutants such as dioxins and numerous dioxin-like compounds, and is associated with the promotion of various malignancies, including lymphoma. The aryl hydrocarbon receptor repressor (AhRR), a ligand-independent, transcriptionally inactive AhR-like protein is known to repress AhR signaling through its ability to compete with the AhR for dimerization with the AhR nuclear translocator (ARNT). While AhRR effectively blocks AhR signaling, several aspects of the mechanism of AhRR’s functions are poorly understood, including suppression of inflammatory responses and its putative role as a tumor suppressor. In a transgenic mouse that overexpresses AhRR (AhRR Tg) we discovered that these mice suppress 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)- and inflammation-induced tumor growth after subcutaneous challenge of EL4 lymphoma cells. Using mouse embryonic fibroblasts (MEF) we found that AhRR overexpression suppresses the AhR-mediated anti-apoptotic response. The AhRR-mediated inhibition of apoptotic resistance was associated with a suppressed expression of interleukin (IL)-1β and cyclooxygenase (COX)-2, which was dependent on activation of protein kinase A (PKA) and the CAAT-enhancer-binding protein beta (C/EBPβ). These results provide mechanistic insights into the role of the AhRR to suppress inflammation and highlight the AhRR as a potential therapeutic target to suppress tumor growth.

Crosstalk between osteoprotegerin (OPG), fatty acid synthase (FASN) and, cycloxygenase-2 (COX-2) in breast cancer: implications in carcinogenesis

The crosstalk between malignant and nonmalignant cells in the tumor microenvironment, as maneuvered by cytokines/chemokines, drives breast cancer progression. In our previous study, we discovered Osteoprotegerin (OPG) as one of the cytokines heavily secreted by breast cancer cells. We demonstrated that OPG is expressed and secreted at very high levels from the highly invasive breast cancer cell lines SUM149PT and SUM1315MO2 as compared to normal human mammary epithelial HMEC cells. OPG was involved in modulating aneuploidy, cell proliferation, and angiogenesis in breast cancer. Mass spectrometry analysis performed in this study revealed OPG interacts with fatty acid synthase (FASN), which is a key enzyme of the fatty acid biosynthetic pathway in breast cancer cells. Further, electron microscopy, immunofluorescence, and fluorescence quantitation assays highlighted the presence of a large number of lipid bodies (lipid droplets) in SUM149PT and SUM1315MO2 cells in comparison to HMEC. We recently showed upregulation of the COX-2 inflammatory pathway and its metabolite PGE2 secretion in SUM149PT and SUM1315MO2 breast cancer cells. Interestingly, human breast cancer tissue samples displayed high expression of OPG, PGE2 and fatty acid synthase (FASN). FASN is a multifunctional enzyme involved in lipid biosynthesis. Immunofluorescence staining revealed the co-existence of COX-2 and FASN in the lipid bodies of breast cancer cells. We reasoned that there might be crosstalk between OPG, FASN, and COX-2 that sustains the inflammatory pathways in breast cancer. Interestingly, knocking down OPG by CRISPR/Cas9 gene editing in breast cancer cells decreased FASN expression at the protein level. Here, we identified cis-acting elements involved in the transcriptional regulation of COX-2 and FASN by recombinant human OPG (rhOPG). Treatment with FASN inhibitor C75 and COX-2 inhibitor celecoxib individually decreased the number of lipid bodies/cell, downregulated phosphorylation of ERK, GSK3β, and induced apoptosis by caspase-3/7 and caspase-9 activation. But a more efficient and effective decrease in lipid bodies/cell and survival kinase signaling was observed upon combining the drug treatments for the aggressive cancer cells. Collectively, the novel biological crosstalk between OPG, FASN, and COX-2 advocates for combinatorial drug treatment to block these players of carcinogenesis as a promising therapeutic target to treat highly invasive breast cancer.

Non-invasive detection of bladder cancer via expression-targeted gene delivery

BACKGROUND

Because of the time and expense associated with the procedures and possible distress to the patient, cystoscopy or other imaging techniques are typically not used for bladder cancer detection before symptoms become present. Alternatively, commercial assays for urinary tumor markers exist but are marred by low sensitivity and high cost. There is a need for a simple and sensitive means of tumor detection, such as via the analysis of urine.

METHODS

Plasmids encoding the secretable reporter Gaussia Luciferase (G.LUC), under the control of cmv, cox2 or opn promoters, were delivered via polyethylenimine into bladder tumor cells in culture and into the bladders of mice. Expression profiles of the reporter were recorded, the optimal times for reporter detection were determined and the relationship of reporter expression with tumor size was calculated.

RESULTS

In vitro results showed that both the cox2 and opn promoters can drive significant expression of G.LUC in bladder carcinoma cells in a targeted fashion. In vivo results demonstrated that the cox2 promoter caused expression of G.LUC at detectable levels in the urine, with local signal maxima occurring at 48 and 72 h post-transfection. G.LUC levels in the urine had a 24-h periodicity, with the periodicity partly being the result of an agent secreted by tumor cells that served to mask the luciferase signal.

CONCLUSIONS

Having shown tumor specificity and having been calibrated with respect to circadian expression patterns, the detection system shows great promise for future investigation of tumor presence both in the urinary bladder and other models of cancer.

Spontaneous Glutamatergic Synaptic Activity Regulates Constitutive COX-2 Expression in Neurons: OPPOSING ROLES FOR THE TRANSCRIPTION FACTORS CREB (cAMP RESPONSE ELEMENT BINDING) PROTEIN AND Sp1 (STIMULATORY PROTEIN-1)

Burgeoning evidence supports a role for cyclooxygenase metabolites in regulating membrane excitability in various forms of synaptic plasticity. Two cyclooxygenases, COX-1 and COX-2, catalyze the initial step in the metabolism of arachidonic acid to prostaglandins. COX-2 is generally considered inducible, but in glutamatergic neurons in some brain regions, including the cerebral cortex, it is constitutively expressed. However, the transcriptional mechanisms by which this occurs have not been elucidated. Here, we used quantitative PCR and also analyzed reporter gene expression in a mouse line carrying a construct consisting of a portion of the proximal promoter region of the mouse COX-2 gene upstream of luciferase cDNA to characterize COX-2 basal transcriptional regulation in cortical neurons. Extracts from the whole brain and from the cerebral cortex, hippocampus, and olfactory bulbs exhibited high luciferase activity. Moreover, constitutive COX-2 expression and luciferase activity were detected in cortical neurons, but not in cortical astrocytes, cultured from wild-type and transgenic mice, respectively. Constitutive COX-2 expression depended on spontaneous but not evoked excitatory synaptic activity and was shown to be N-methyl-d-aspartate receptor-dependent. Constitutive promoter activity was reduced in neurons transfected with a dominant-negative cAMP response element binding protein (CREB) and was eliminated by mutating the CRE-binding site on the COX-2 promoter. However, mutation of the stimulatory protein-1 (Sp1)-binding site resulted in an N-methyl-d-aspartate receptor-dependent enhancement of COX-2 promoter activity. Basal binding of the transcription factors CREB and Sp1 to the native neuronal COX-2 promoter was confirmed. In toto, our data suggest that spontaneous glutamatergic synaptic activity regulates constitutive neuronal COX-2 expression via Sp1 and CREB protein-dependent transcriptional mechanisms.

Prostacyclin regulates bone growth via the Epac/Rap1 pathway

Prostaglandins, particularly PGE2, are important to adult bone and joint health, but how prostaglandins act on growth plate cartilage to affect bone growth is unclear. We show that growth plate cartilage is distinct from articular cartilage with respect to cyclooxygenase (COX)-2 mRNA expression; although articular chondrocytes express very little COX-2, COX-2 expression is high in growth plate chondrocytes and is increased by IGF-I. In bovine primary growth plate chondrocytes, ATDC5 cells, and human metatarsal explants, inhibition of COX activity with nonsteroidal antiinflammatory drugs (NSAIDs) inhibits chondrocyte proliferation and ERK activation by IGF-I. This inhibition is reversed by prostaglandin E2 and prostacyclin (PGI2) but not by prostaglandin D2 or thromboxane B2. Inhibition of COX activity in young mice by ip injections of NSAIDs causes dwarfism. In growth plate chondrocytes, inhibition of proliferation and ERK activation by NSAIDs is reversed by forskolin, 8-bromoadenosine, 3',5'-cAMP and a prostacyclin analog, iloprost. The inhibition of proliferation and ERK activation by celecoxib is also reversed by 8CPT-2Me-cAMP, an activator of Epac, implicating the small G protein Rap1 in the pathway activated by iloprost. These results imply that prostacyclin is required for proper growth plate development and bone growth.

A computational prospect to aspirin side effects: aspirin and COX-1 interaction analysis based on non-synonymous SNPs

Aspirin (ASA) is a commonly used nonsteroidal anti-inflammatory drug (NSAID), which exerts its therapeutic effects through inhibition of cyclooxygenase (COX) isoform 2 (COX-2), while the inhibition of COX-1 by ASA leads to apparent side effects. In the present study, the relationship between COX-1 non-synonymous single nucleotide polymorphisms (nsSNPs) and aspirin related side effects was investigated. The functional impacts of 37 nsSNPs on aspirin inhibition potency of COX-1 with COX-1/aspirin molecular docking were computationally analyzed, and each SNP was scored based on DOCK Amber score. The data predicted that 22 nsSNPs could reduce COX-1 inhibition, while 15 nsSNPs showed increasing inhibition level in comparison to the regular COX-1 protein. In order to perform a comparing state, the Amber scores for two Arg119 mutants (R119A and R119Q) were also calculated. Moreover, among nsSNP variants, rs117122585 represented the closest Amber score to R119A mutant. A separate docking computation validated the score and represented a new binding position for ASA that acetyl group was located within the distance of 3.86Å from Ser529 OH group. This could predict an associated loss of activity of ASA through this nsSNP variant. Our data represent a computational sub-population pattern for aspirin COX-1 related side effects, and provide basis for further research on COX-1/ASA interaction.

The COX-2 selective blocker etodolac inhibits TNFα-induced apoptosis in isolated rabbit articular chondrocytes

Chondrocyte apoptosis contributes to the disruption of cartilage integrity in osteoarthritis (OA). Recently, we reported that activation of volume-sensitive Cl⁻ current (I_Cl,vol) mediates cell shrinkage, triggering apoptosis in rabbit articular chondrocytes. A cyclooxygenase (COX) blocker is frequently used for the treatment of OA. In the present study, we examined in vitro effects of selective blockers of COX on the TNFα-induced activation of I_Cl,vol in rabbit chondrocytes using the patch-clamp technique. Exposure of isolated chondrocytes to TNFα resulted in an obvious increase in membrane Cl⁻ conductance. The TNFα-evoked Cl⁻ current exhibited electrophysiological and pharmacological properties similar to those of I_Cl,vol. Pretreatment of cells with selective COX-2 blocker etodolac markedly inhibited I_Cl,vol activation by TNFα as well as subsequent apoptotic events such as apoptotic cell volume decrease (AVD) and elevation of caspase-3/7 activity. In contrast, a COX-1 blocker had no effect on the decrease in cell volume or the increase in caspase-3/7 activity induced by TNFα. Thus, the COX-2-selective blocker had an inhibitory effect on TNFα-induced apoptotic events, which suggests that this drug would have efficacy for the treatment of OA.

Augmented epithelial multidrug resistance-associated protein 4 expression in peritoneal endometriosis: regulation by lipoxin A(4)

OBJECTIVE

To compare the expression of the prostaglandin (PG) E(2) transporter multidrug resistance-associated protein 4 (MRP4) in eutopic and ectopic endometrial tissue from endometriosis patients with that of control subjects and to examine whether MRP4 is regulated by the antiinflammatory lipid lipoxin A(4) (LXA(4)) in endometriotic epithelial cells.

DESIGN

Molecular analysis in human samples and a cell line.

SETTING

Two university hospitals and a private clinic.

PATIENT(S)

A total of 59 endometriosis patients and 32 age- and body mass index-matched control subjects undergoing laparoscopy or hysterectomy.

INTERVENTION(S)

Normal, eutopic, and ectopic endometrial biopsies as well as peritoneal fluid were obtained during surgery performed during the proliferative phase of the menstrual cycle. 12Z endometriotic epithelial cells were used for in vitro mechanistic studies.

MAIN OUTCOME MEASURE(S)

Tissue MRP4 mRNA levels were quantified by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and localization was analyzed with the use of immunohistochemistry. Cellular MRP4 mRNA and protein were quantified by qRT-PCR and Western blot, respectively. PGE(2) was measured in peritoneal fluid and cell supernatants using an enzyme immunoassay (EIA).

RESULT(S)

MRP4 was expressed in eutopic and ectopic endometrium, where it was overexpressed in peritoneal lesions and localized in the cytoplasm of glandular epithelial cells. LXA(4) attenuated MRP4 mRNA and protein levels in endometriotic epithelial cells in a dose-dependent manner, while not affecting the expression of enzymes involved in PGE(2) metabolism. Investigations employing receptor antagonists and small interfering RNA revealed that this occurred through estrogen receptor α. Accordingly, LXA(4) treatment inhibited extracellular PGE(2) release.

CONCLUSION(S)

We report for the first time that MRP4 is expressed in human endometrium, elevated in peritoneal endometriosis, and modulated by LXA(4) in endometriotic epithelial cells.

Targeted exchange of an expression cassette encoding cyclooxygenase-2 at the Ptgs1 locus

Defining the multi-faceted roles of prostaglandins has been facilitated by studying mice with manipulated expression of the two enzymes encoding cyclooxygenase (COX) via gene targeting, with either knocked down expression of COX-1 or COX-2, a knocked-in COX-2 active site mutation and exchange of COX isoforms by insertion of a cassette encoding COX-1 into the COX-2 (Ptgs2) gene to create COX-1>COX-2 mice. Here, we sought to extend these studies by creating a new induced mutant strain with manipulated COX expression. We carried out gene targeting at the Ptgs1 locus to knock-in an expression cassette encoding COX-2 under Ptgs1 regulatory elements in a manner analogous used in COX-1>COX-2 targeting. While successful gene targeting at the Ptgs1 locus was achieved, the strategy did not yield a "basal" increase of COX-2 under Ptgs1 gene regulatory control in various cells and tissues from COX-2>COX-1 mice but rather resulted in a Ptgs1 null allele. Possible explanations as to why this strategy was unsuccessful include non-functionality of the hybrid signal peptide and aberrant transcript processing. Since a similar strategy had previously worked (i.e. COX-1 cDNA knocked-in to the Ptgs2 locus; COX-1>COX-2 mice) interpretations of our findings on murine COX biology and gene targeting are discussed.

N-1 and C-3 substituted indole Schiff bases as selective COX-2 inhibitors: synthesis and biological evaluation

A group of N-1 and C-3 disubstituted-indole Schiff bases bearing an indole N-1 (R'=H, CH(2)Ph, COPh) substituent in conjunction with a C-3 -C=HN-C(6)H(4)-4-X (X=F, Me, CF(3), Cl) substituent were synthesized and evaluated as inhibitors of cyclooxygenase (COX) isozymes (COX-1/COX-2). Within this group of Schiff bases, compounds 15 (R(1)=CH(2)Ph, X=F), 17 (R(1)=CH(2)Ph, X=CF(3)), 18 (R(1)=COPh, X=F) and 20 (R(1)=COPh, X=CF(3)) were identified as effective and selective COX-2 inhibitors (COX-2 IC(50)'s=0.32-0.84 μM range; COX-2 selectivity index (SI)=113 to >312 range). 1-Benzoyl-3-[(4-trifluoromethylphenylimino)methyl]indole (20) emerged as the most potent (COX-1 IC(50) >100 μM; COX-2 IC(50)=0.32 μM) and selective (SI >312) COX-2 inhibitor. Furthermore, compound 20 is a selective COX-2 inhibitor in contrast to the reference drug indomethacin that is a potent and selective COX-1 inhibitor (COX-1 IC(50)=0.13 μM; COX-2 IC(50)=6.9 μM, COX-2 SI=0.02). Molecular modeling studies employing compound 20 showed that the phenyl CF(3) substituent attached to the CN spacer is positioned near the secondary pocket of the COX-2 active site, the CN nitrogen atom is hydrogen bonded (N···NH=2.85 Å) to the H90 residue, and the indole N-1 benzoyl is positioned in a hydrophobic pocket of the COX-2 active site near W387.

Aspirin analogues as dual cyclooxygenase-2/5-lipoxygenase inhibitors: synthesis, nitric oxide release, molecular modeling, and biological evaluation as anti-inflammatory agents

Analogues of aspirin were synthesized through an efficient one-step reaction in which the carboxyl group was replaced by an ethyl ester, and/or the acetoxy group was replaced by an N-substituted sulfonamide (SO(2)NHOR(2):R(2) =H, Me, CH(2)Ph) pharmacophore. These analogues were designed for evaluation as dual cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitors. In vitro COX-1/COX-2 isozyme inhibition studies identified compounds 11 (CO(2) H, SO(2)NHOH), 12 (CO(2)H, SO(2)NHOCH(2)Ph), and 16 (CO(2)Et, SO(2)NHOH) as highly potent and selective COX-2 inhibitors (IC(50) range: 0.07-0.7 μM), which exhibited appreciable in vivo anti-inflammatory activity (ED(50) range: 23.1-31.4 mg kg(-1)). Moreover, compounds 11 (IC(50) =0.2 μM) and 16 (IC(50) =0.3 μM), with a sulfohydroxamic acid (SO(2)NHOH) moiety showed potent 5-LOX inhibitory activity. Furthermore, the SO(2)NHOH moiety present in compounds 11 and 16 was found to be a good nitric oxide (NO) donor upon incubation in phosphate buffer at pH 7.4. Molecular docking studies in the active binding site of COX-2 and 5-LOX provided complementary theoretical support for the experimental biological structure-activity data acquired.

Proliferation of Hepatic Oval Cells via Cyclooxygenase-2 and Extracellular Matrix Protein Signaling during Liver Regeneration Following 2-AAF/Partial Hepatectomy in Rats

BACKGROUND/AIMS

In the 2-acetylaminofluorene (2-AAF)/70% partial hepatectomy (PHx) model, the mechanism underlying the differentiation of activated hepatic oval cells (HOCs) into hepatocytes and bile ductile cells is unclear. We investigated the role of cyclooxygenase-2 (COX-2) in HOCs and the relationship between COX-2 and extracellular matrix proteins in cellular proliferation.

METHODS

Reverse transcription-polymerase chain reaction, immunohistochemical staining, and Western blotting were used to assess COX-2 expression. The co-localization of COX-2 with Thy1, c-Met, epithelial cell adhesion molecule, and α-smooth muscle actin was also examined. Additionally, we investigated whether connective tissue growth factor (CTGF), fibronectin (FN), extracellular signal-regulated kinase 1/2 (P-ERK1/2), and AKT were expressed in HOCs.

RESULTS

The expression of COX-2, prostaglandin E2 receptors, and c-Met was upregulated in HOCs. However, HOCs treated with the COX-2 inhibitor NS398 showed decreased COX-2, CTGF, FN, and AKT expression, whereas P-ERK1/2 was unaffected. Additionally, NS398 inhibited HOC proliferation, but not the proliferation of HOCs cultured on FN-coated dishes. Furthermore, the proliferative response of HOCs treated with NS398 was reversed by hepatic growth factor treatment.

CONCLUSIONS

These results suggest that HOC proliferation is mediated through COX-2, extracellular FN expression, and AKT activation. Thus, COX-2 plays an important role in HOC proliferation following acute injury.

Analysis of promoters and expression-targeted gene therapy optimization based on doubling time and transfectability

Genes under the control of the cyclooxygenase-2 (Cox-2), human epidermal growth factor receptor 2 (Her-2), and survivin promoters were constructed and delivered to murine and human carcinoma cells. It was found that (P)Cox-2-driven reporter expression was strong and correlated well with endogenous Cox-2 levels, while (P)Her-2 and (P)survivin yielded poor results, consistent with the three distinct expression mechanisms used by cancer cells to overexpress the endogenous versions of the selected genes. The (P)Cox-2 was then used to drive the expression of caspase genes both in vitro and in vivo to bring about targeted apoptosis of carcinoma cells successfully. The results led to the following conclusions. 1) When selecting a promoter/enhancer for expression-targeted gene delivery, it is not enough to perform a microarray on some tumor tissue and select the control element associated with the greatest amount of gene up-regulation vs. normal controls. The mechanism of expression for the particular gene should be taken into account to prevent lengthy and costly research trials. 2) When overexpression is due to activator binding, a predictive model based on endogenous gene expression levels, overall cell transfectability, and cell doubling rates can be used to predict expression-targeted gene delivery outcomes with significant accuracy.

Cyclooxygenase-2 in oncogenesis

Compelling experimental and clinical evidence supports the notion that cyclooxygenase-2, the inducible isoform of cyclooxygenase, plays a crucial role in oncogenesis. Clinical and epidemiological data indicate that aberrant regulation of cyclooxygenase-2 in certain solid tumors and hematological malignancies is associated with adverse clinical outcome. Moreover, findings extrapolated from experimental studies in cultured tumor cells and animal tumor models indicate that cyclooxygenase-2 critically influences all stages of tumor development from tumor initiation to tumor progression. Cyclooxygenase-2 elicits cell-autonomous effects on tumor cells resulting in stimulation of growth, increased cell survival, enhanced tumor cell invasiveness, stimulation of neovascularization, and tumor evasion from the host immune system. Additionally, the oncogenic effects of cyclooxygenase-2 stem from its unique ability to impact tumor cell surroundings and create a proinflammatory environment conducive for tumor development, growth and progression. The initial enthusiasm generated by the availability of cyclooxygenase-2 selective inhibitors for cancer prevention and therapy has been lessened by the severe cardiovascular adverse side effects associated with their long-term use, as well as by the mixed results of recent clinical trials evaluating the efficacy of cyclooxygenase-2 inhibitors in adjuvant chemotherapy. Therefore, our ability to efficiently target the oncogenic effects of cyclooxygenase-2 for therapeutic and preventive purposes strictly depends on a better understanding of the spatial and temporal aspects of its activation in tumor cells along with a clearer elucidation of the signaling networks whereby cyclooxygenase-2 affects tumor cells and their interactions with the tumor microenvironment. This knowledge has the potential of leading to the identification of novel cyclooxygenase-2-dependent molecular and signaling networks that can be exploited to improve cancer prevention and therapy.

Mouse models of gastric tumors: Wnt activation and PGE2 induction

Accumulating evidence has suggested that cooperation of oncogenic activation and the host responses is important for cancer development. In gastric cancer, activation of Wnt signaling appears to be a major oncogenic pathway that causes tumorigenesis. In the chronic gastritis caused by Helicobacter pylori infection, cyclooxigenase-2 induces prostaglandin E(2) (PGE(2)) biosythesis, which plays an important role in tumorigenesis. We constructed a series of mouse models and investigated the role of each pathway in the gastric tumorigenesis. Wnt activation in gastric epithelial cells suppresses differentiation, and induces development of preneoplastic lesions. On the other hand, induction of the PGE(2) pathway in gastric mucosa induces development of spasmolytic polypeptide-expressing metaplasia (SPEM), which is a possible preneoplastic metaplasia. Importantly, simultaneous activation of Wnt and PGE(2) pathways leads to dysplastic gastric tumor development. Moreover, induction of the PGE(2) pathway also promotes gastric hamartoma development when bone morphogenetic protein (BMP) signaling is suppressed. These results indicate that alteration in the Wnt or BMP signaling impairs epithelial differentiation, and the PGE(2) pathway accelerates tumor formation regardless of the types of oncogenic pathways. We review the phenotypes and gene expression profiles of the respective models, and discuss the cooperation of oncogenic pathways and host responses in gastric tumorigenesis.

NFAT and CREB regulate Kaposi's sarcoma-associated herpesvirus-induced cyclooxygenase 2 (COX-2)

COX-2 has been implicated in Kaposi's sarcoma-associated herpesvirus (KSHV) latency and pathogenesis (A. George Paul, N. Sharma-Walia, N. Kerur, C. White, and B. Chandran, Cancer Res. 70:3697-3708, 2010; P. P. Naranatt, H. H. Krishnan, S. R. Svojanovsky, C. Bloomer, S. Mathur, and B. Chandran, Cancer Res. 64:72-84, 2004; N. Sharma-Walia, A. G. Paul, V. Bottero, S. Sadagopan, M. V. Veettil, N. Kerur, and B. Chandran, PLoS Pathog. 6:e1000777, 2010; N. Sharma-Walia, H. Raghu, S. Sadagopan, R. Sivakumar, M. V. Veettil, P. P. Naranatt, M. M. Smith, and B. Chandran, J. Virol. 80:6534-6552, 2006). However, the precise regulatory mechanisms involved in COX-2 induction during KSHV infection have never been explored. Here, we identified cis-acting elements involved in the transcriptional regulation of COX-2 upon KSHV de novo infection. Promoter analysis using human COX-2 promoter deletion and mutation reporter constructs revealed that nuclear factor of activated T cells (NFAT) and the cyclic AMP (cAMP) response element (CRE) modulate KSHV-mediated transcriptional regulation of COX-2. Along with multiple KSHV-induced signaling pathways, infection-induced prostaglandin E(2) (PGE(2)) also augmented COX-2 transcription. Infection of endothelial cells markedly induced COX-2 expression via a cyclosporine A-sensitive, calcineurin/NFAT-dependent pathway. KSHV infection increased intracellular cAMP levels and activated protein kinase A (PKA), which phosphorylated the CRE-binding protein (CREB) at serine 133, which probably led to interaction with CRE in the COX-2 promoter, thereby enhancing COX-2 transcription. PKA selective inhibitor H-89 pretreatment strongly inhibited CREB serine 133, indicating the involvement of a cAMP-PKA-CREB-CRE loop in COX-2 transcriptional regulation. In contrast to phosphatidylinositol 3-kinase and protein kinase C, inhibition of FAK and Src effectively reduced KSHV infection-induced COX-2 transcription and protein levels. Collectively, our study indicates that mediation of COX-2 transcription upon KSHV infection is a paradigm of a complex regulatory milieu involving the interplay of multiple signal cascades and transcription factors. Intervention at each step of COX-2/PGE(2) induction can be used as a potential therapeutic target to treat KSHV-associated neoplasm and control inflammatory sequels of KSHV infection.

Effect of Non-Steroidal Anti-Inflammatory Drugs on Bone Healing

Nonspecific and COX-2 selective nonsteroidal anti-inflammatory drugs (NSAIDs) function by inhibiting the cyclooxygenase isoenzymes and effectively reduce pain and inflammation attributed to acute or chronic musculoskeletal pathologies. However, use of NSAIDs as an analgesic is thought to negatively contribute to bone healing. This review strived to provide a thorough unbiased analysis of the current research conducted on animals and humans regarding NSAIDs and their effect on bone healing. Specifically, this review discusses the role of animal models, dosing regiments, and outcome parameters when examining discrepancies about NSAIDS and their effects on bone regeneration. The role of COX-2 in bone regeneration needs to be better defined in order to further elucidate the impact of NSAIDs on bone healing.

Regulation of transforming growth factor-beta-dependent cyclooxygenase-2 expression in fibroblasts

Abnormal transforming growth factor-beta (TGF-beta) signaling is a critical contributor to the pathogenesis of various human diseases ranging from tissue fibrosis to tumor formation. Excessive TGF-beta signaling stimulates fibrotic responses. Recent research has focused in the main on the antiproliferative effects of TGF-beta in fibroblasts, and it is presently understood that TGF-beta-stimulated cyclooxygenase-2 (COX-2) induction in fibroblasts is essential for antifibroproliferative effects of TGF-beta. Both TGF-beta and COX-2 have been implicated in tumor growth, invasion, and metastasis, and therefore tumor-associated fibroblasts are a recent topic of interest. Here we report the identification of positive and negative regulatory factors of COX-2 expression induced by TGF-beta as determined using proteomic approaches. We show that TGF-beta coordinately up-regulates three factors, heterogeneous nuclear ribonucleoprotein A/B (HNRPAB), nucleotide diphosphate kinase A (NDPK A), and nucleotide diphosphate kinase A (NDPK B). Functional pathway analysis showed that HNRPAB augments mRNA and protein levels of COX-2 and subsequent prostaglandin E(2) (PGE(2)) production by suppressing degradation of COX-2 mRNA. In contrast, NDPK A and NDPK B attenuated mRNA and protein levels of COX-2 by affecting TGF-beta-Smad2/3/4 signaling at the receptor level. Collectively, we report on a new regulatory pathway of TGF-beta in controlling expression of COX-2 in fibroblasts, which advances our understanding of pathophysiological mechanisms of TGF-beta.

Prostaglandin E2, Wnt, and BMP in gastric tumor mouse models

The development of gastric cancer is closely associated with Helicobacter pylori (H. pylori) infection. The expression of cylooxigenase-2 (COX-2), a rate-limiting enzyme for prostaglandin biosynthesis, is induced in H. pylori-associated chronic gastritis, which thus results in the induction of proinflammatory prostaglandin, PGE(2). The COX-2/PGE(2) pathway plays a key role in gastric tumorigenesis. On the other hand, several oncogenic pathways have been shown to trigger gastric tumorigenesis. The activation of Wnt/beta-catenin signaling is found in 30-50% of gastric cancers, thus suggesting that Wnt signaling plays a causal role in gastric cancer development. Mutations in the bone morphogenetic protein (BMP) signaling pathway are responsible for the subset of juvenile polyposis syndrome (JPS) that develops hamartomas in the gastrointestinal tract. BMP suppression appears to contribute to gastric cancer development because gastric cancer risk is increased in JPS. Wnt signaling is important for the maintenance of gastrointestinal stem cells, while BMP promotes epithelial cell differentiation. Accordingly, it is possible that both Wnt activation and BMP suppression can cause gastric tumorigenesis through enhancement of the undifferentiated status of epithelial cells. Recent mouse model studies have indicated that induction of the PGE(2) pathway is required for the development of both gastric adenocarcinoma and hamartoma in the Wnt-activated and BMP-suppressed gastric mucosa, respectively. This article reviews the involvement of the PGE(2), Wnt, and BMP pathways in the development of gastric cancer, and gastric phenotypes that are found in transgenic mouse models of PGE(2) induction, Wnt activation, BMP suppression, or a combination of these pathways.

Involvement of cyclooxygenase-2 in rat models of conjunctivitis

PURPOSE

Using two animal models to determine which isoform of cyclooxygenase (COX), constitutive COX-1 or inducible COX-2, is involved in the progression of anterior ocular inflammation.

METHODS

Lambda-carrageenan (500 mg/eye) or bacterial lipopolysaccharide (LPS; 3 mg/eye) was injected into rat conjunctiva to induce conjunctivitis. Vascular permeability in inflamed conjunctiva was measured by uptake of systemic Evans blue. Changes in mRNA for COX-1 and COX-2 in conjunctiva were detected by RT-PCR. Changes in COX-2 protein were detected by immunoblotting after immunoprecipitation. To assess involvement of COX-2 in carrageenan and LPS-induced conjunctivitis, NS-398 (a selective COX-2 inhibitor) or indomethacin (non-selective COX inhibitor) was topically administrated at 15 and 30 minutes before inflammatory stimulator-injection.

RESULTS

In the carrageenan-injected model, the dye content of conjunctiva (12.4 +/- 2.8 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.7 +/-1.1 mg/eye). mRNA for COX-2 was significantly increased by 2 hours and gradually increased until 24 hours; COX-1 mRNA did not show major changes until 24 hours after injection. COX-2 protein was markedly elevated 4 hours after injection of carrageenan. COX-2 protein levels were well correlated with increased mRNA levels. In the LPS-injected model, the dye content of conjunctiva (5.8 +/- 1.2 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.1 +/- 0.6 mg/eye). Expression of COX-2 mRNA was increased 1 hour after injection, peaked at 2 hours, and decreased at 4 hours. mRNA for COX-1 did not change by 24 hours. COX- 2 protein increased 2 hours after injection of LPS. COX-2 protein levels were well correlated with increased mRNA. Topical administration of 1% NS-398 exhibited strong inhibition of dye-leakage into conjunctiva 4 hours after injection of carrageenan or LPS, since 59% or 83% of dye-uptake were inhibited, respectively. 1% of indomethacin eye drops showed only a minimal effect.

CONCLUSIONS

These results suggest that the mechanism for anterior ocular inflammation may be due to up-regulation of COX-2.

Alterations in excitotoxicity and prostaglandin metabolism in a transgenic mouse model of Alzheimer's disease

To address the potential impact of presenilin mutations on the prostaglandin metabolism in a neurodegenerative model of glutamatergic excitotoxicity, we injected kainic acid intraperitoneally (30mg/kg body weight) into mice over-expressing the human N141I mutation of presenilin-2, which is known to cause an early-onset form of Alzheimer's disease. We compared the seizure activity as well as seizure lethality in 2- and 6-month-old mice, transgenic for the above-mentioned point mutation, and their wildtype littermates and found that mice harboring the hN141I mutation showed a relative resistance to excitotoxic treatment. This was associated with a constituitively reduced expression of the cyclooxygenases COX-1 and COX-2 in the hippocampus of N141I presenilin-2 mice and a reduced induction of COX-2 expression post-kainate injection. In the past, clinical trials have suggested that both non-steroidal anti-inflammatory drugs, which impact upon a cell's prostaglandin metabolism, and glutamatergic antagonists might be of benefit to patients suffering from Alzheimer's-type dementias. Yet, the exact mechanism by which these drugs are beneficial remains unclear, although it seems possible that presenilins might be implicated in the process, at least in the case of early-onset forms. The data presented here strongly support the notion of an implication of presenilins in the alterations in the prostaglandin system, which have been observed in Alzheimer's disease and may contribute to the underlying pathogenesis of the disease.

Bromelain inhibits COX-2 expression by blocking the activation of MAPK regulated NF-kappa B against skin tumor-initiation triggering mitochondrial death pathway

Chemoprevention impels the pursuit for either single targeted or cocktail of multi-targeted agents. Bromelain, potential agent in this regard, is a pharmacologically active compound, present in stems and fruits of pineapple (Ananas cosmosus), endowed with anti-inflammatory, anti-invasive and anti-metastatic properties. Herein, we report the anti tumor-initiating effects of bromelain in 2-stage mouse skin tumorigenesis model. Pre-treatment of bromelain resulted in reduction in cumulative number of tumors (CNT) and average number of tumors per mouse. Preventive effect was also comprehended in terms of reduction in tumor volume up to a tune of approximately 65%. Components of the cell signaling pathways, connecting proteins involved in cell death were targeted. Bromelain treatment resulted in upregulation of p53 and Bax and subsequent activation of caspase 3 and caspase 9 with concomitant decrease in Bcl-2. A marked inhibition in cyclooxygenase-2 (Cox-2) expression and inactivation of nuclear factor-kappa B (NF-kappaB) was recorded, as phosphorylation and consequent degradation of I kappa B alpha was blocked by bromelain. Also, bromelain treatment curtailed extracellular signal regulated protein kinase (ERK1/2), p38 mitogen-activated protein kinase (MAPK) and Akt activity. The basis of anti tumor-initiating activity of bromelain was revealed by its time dependent reduction in DNA nick formation and increase in percentage prevention. Thus, modulation of inappropriate cell signaling cascades driven by bromelain is a coherent approach in achieving chemoprevention.

Cardiovascular risks of COX inhibition: current perspectives

BACKGROUND

NSAIDs are among the most commonly used pharmacotherapeutic agents worldwide. As the long-term use of these drugs is associated with serious gastrointestinal side effects, a new subgroup of COX-2 selective NSAIDs was developed. It was thought that the therapeutic strategy underlying the development of these newer compounds would enable them to provide the same analgesic and anti-inflammatory benefits as those of their traditional counterparts but perhaps offer a much safer gastrointestinal profile. Much scientific data has accumulated over the last few years, however, raising concerns regarding the increased cardiovascular complications associated with the use of COX-2 selective NSAIDs, and perhaps of the traditional NSAIDs as well.

OBJECTIVE

To review current and emerging evidence related to the cardiovascular effects of COX inhibitors and examine the clinical implications.

METHOD

We studied data from basic clinical research, non-randomized analyses, and randomized trials of COX inhibitors that investigated their cardiovascular effects.

CONCLUSION

Both COX-2 selective and traditional NSAIDs are associated with a moderately increased risk of cardiovascular events.

Bioavailable constituents/metabolites of pomegranate (Punica granatum L) preferentially inhibit COX2 activity ex vivo and IL-1beta-induced PGE2 production in human chondrocytes in vitro

Several recent studies have documented that supplementation with pomegranate fruit extract inhibits inflammatory symptoms in vivo. However, the molecular basis of the observed effects has not been fully revealed. Although previous studies have documented the inhibition of nitric oxide and cyclooxygenase (COX) activity in vitro by plant and fruit extracts added directly into the culture medium but whether concentrations of bioactive compounds sufficient enough to exert such inhibitory effects in vivo can be achieved through oral consumption has not been reported. In the present study we determined the effect of rabbit plasma obtained after ingestion of a polyphenol rich extract of pomegranate fruit (PFE) on COX enzyme activity ex vivo and the IL-1beta-induced production of NO and PGE2 in chondrocytes in vitro. Plasma samples collected before and 2 hr after supplementation with PFE were tested. Plasma samples collected after oral ingestion of PFE were found to inhibit the IL-1beta-induced PGE2 and NO production in chondrocytes. These same plasma samples also inhibited both COX-1 and COX-2 enzyme activity ex vivo but the effect was more pronounced on the enzyme activity of COX-2 enzyme. Taken together these results provide additional evidence of the bioavailability and bioactivity of compounds present in pomegranate fruit after oral ingestion. Furthermore, these studies suggest that PFE-derived bioavailable compounds may exert an anti-inflammatory effect by inhibiting the inflammatory cytokine-induced production of PGE2 and NO in vivo.

Identification of a novel repressor element in the cyclo-oxygenase-2 promoter and its nuclear binding protein

Cyclo-oxygenase-2 (COX-2) has important functions in many diseases. Although its transcriptional regulation has been investigated in considerable detail, some important elements remain unknown. The aim of the present study was to demonstrate the existence of a novel repressor element in the mouse COX-2 promoter and characterize some of its binding proteins. In order to identify the repressor element, the activity of the mouse COX-2 promoter was investigated in the pancreatic beta-cell line RINm5F using a series of deletion and mutant constructs. The ability of nuclear proteins to bind to this repressor element was then determined by an electrophoretic mobility shift assay and the proteins binding to this repressor element were purified and identified by mass spectrometry. One of the nuclear proteins identified was overexpressed to examine its inhibitory effect on COX-2 promoter activity. We found a novel repressor element located from nucleotides -655 to -632 of the mouse COX-2 promoter region. Some proteins from RINm5F cell nuclear extracts bound to this element, one of which was identified as non-POU-domain-containing, octamer-binding protein (NonO). Overexpression of NonO significantly inhibited wild-type COX-2 promoter activity, but had no effect when the repressor element was mutated. In conclusion, we have demonstrated that a regulatory 'spot' is present in the COX-2 promoter. This provides additional data on COX-2 gene regulation and may provide an insight into the clinical treatment of diseases where COX-2 is highly expressed.

Nutritionally essential fatty acids and biologically indispensable cyclooxygenases

The study of cyclooxygenases (COXs), targets of aspirin and related drugs, is rooted in the discovery of essential fatty acids (EFAs). There are two COXs that convert EFAs, primarily arachidonic acid, to prostaglandins. Each COX is involved with distinct biologies. COX-1 expression is constitutive while COX-2 is inducible. The two COXs might have evolved partly to permit prostaglandin formation at different tissue sites. However, COX-2 is sometimes induced in cells already expressing COX-1, and in these instances, COX-2 functions while COX-1 is latent. This can occur because of unique biochemical properties of COX-2 that enable cells to form prostaglandins when arachidonic acid comprises a small fraction of available fatty acids and the concentrations of peroxides that are necessary for COX to function are low.

Preclinical pharmacology profile of CS-706, a novel cyclooxygenase-2 selective inhibitor, with potent antinociceptive and anti-inflammatory effects

We report here the preclinical anti-inflammatory profile of CS-706 [2-(4-ethoxyphenyl)-4-methyl-1-(4-sulfamoylphenyl)-1H-pyrrole], a novel cyclooxygenase-2 (COX-2) selective inhibitor. CS-706 selectively inhibited COX-2 in a human whole blood assay with an IC(50) of 0.31 microM, compared with an IC(50) of 2.2 microM for COX-1. The selectivity ratio of CS-706 was higher than those of the conventional non-steroidal anti-inflammatory drugs naproxen, indomethacin, and Diclofenac-Na, whereas it was lower than those of rofecoxib, valdecoxib and etoricoxib. It was similar to that of celecoxib. The pharmacokinetic profile of CS-706 showed rapid absorption and dose-proportional exposure after oral administration to rats. CS-706 inhibited prostaglandin E(2) production in inflamed tissue induced by yeast-injection in rats with potency similar to that of indomethacin. However, it inhibited gastric mucosal prostaglandin E(2) production in normal rats weakly compared with indomethacin. CS-706 ameliorated both yeast-induced inflammatory acute pain (ED(50)=0.0090 mg/kg) and adjuvant-induced chronic arthritic pain (ED(50)=0.30 mg/kg) in rats. CS-706 showed more potent antinociceptive activity than celecoxib and rofecoxib in these models. In an adjuvant-induced arthritic model in rats, CS-706 suppressed foot swelling prophylactically with an ID(50) of 0.10 mg/kg/day, and decreased foot swelling in the established arthritis therapeutically in a dose range of 0.040 to 1.0 mg/kg/day. Single administration of up to 100 mg/kg of CS-706 induced no significant gastric lesions in rats. In conclusion, CS-706 is a COX-2-selective inhibitor with a potent antinociceptive and anti-inflammatory activity and a gastric safety profile.