Licofelone, a novel 5-LOX/COX-inhibitor, attenuates leukocyte rolling and adhesion on endothelium under flow

Licofelone, a potent COX/5-LOX inhibitor and a novel option for treatment of neurological disorders

Neurological disorders result in disability and morbidity. Neuroinflammation is a key factor involved in progression or resolution of a series of neurological disorders like Huntington disease (HD), Parkinson's disease (PD), Alzheimer's disease (AD), Spinal Cord Injury (SCI), and Seizure. Thereby, anti-inflammatory drugs have been developed to improve the neurodegenerative impairments. Licofelone is an approved osteoarthritis drug that inhibits both the COX (cyclooxygenase) and 5-LOX (lipoxygenase) pathways. Licofelone has pain-relieving and anti-inflammatory effects and it was shown to have neuroprotective properties in the central nervous system, which is implicated in its regulatory effect on the COX/5-LOX pathway, inflammatory cytokines, and immune responses. In this study, we briefly review the various features of neurological disorders and the function of COX/LOX in their flare up and current pharmacological products for their management. Moreover, this review attempts to summarize potential therapeutics that target the immune responses within the central nervous system. A better understanding of the interactions between Licofelone and the nervous systems will be crucial to demonstrate the possible efficacy of Licofelone in neurological disorders.

Nonsteroidal Anti-Inflammatory Therapy: A Journey Toward Safety

The efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) against inflammation, pain, and fever has been supporting their worldwide use in the treatment of painful conditions and chronic inflammatory diseases until today. However, the long-term therapy with NSAIDs was soon associated with high incidences of adverse events in the gastrointestinal tract. Therefore, the search for novel drugs with improved safety has begun with COX-2 selective inhibitors (coxibs) being straightaway developed and commercialized. Nevertheless, the excitement has fast turned to disappointment when diverse coxibs were withdrawn from the market due to cardiovascular toxicity. Such events have once again triggered the emergence of different strategies to overcome NSAIDs toxicity. Here, an integrative review is provided to address the breakthroughs of two main approaches: (i) the association of NSAIDs with protective mediators and (ii) the design of novel compounds to target downstream and/or multiple enzymes of the arachidonic acid cascade. To date, just one phosphatidylcholine-associated NSAID has already been approved for commercialization. Nevertheless, the preclinical and clinical data obtained so far indicate that both strategies may improve the safety of nonsteroidal anti-inflammatory therapy.

COX-2-dependent and independent effects of COX-2 inhibitors and NSAIDs on proatherogenic changes in human monocytes/macrophages

It is the second decade of controversy regarding the cardiovascular effects of cyclo-oxygenase-2 (COX-2) inhibitors. At this time, celecoxib is the only available COX-2-specific inhibitor for treatment of pain and inflammation. Therefore, the present study was designed primarily to determine the impact of celecoxib on cholesterol handling (uptake via scavenger receptors and efflux from the cells) and foam cell formation in human THP-1 macrophages, followed by comparison to rofecoxib and other non-steroidal anti-inflammatory drugs (NSAIDs). THP-1 human macrophages and peripheral blood mononuclear cells were incubated with: celecoxib, rofecoxib, naproxen (at 5, 10, 25 µM) and acetaminophen (0.5 mM, 1 mM)±oxidized low-density lipoprotein (oxLDL, 25 µg/mL). Scavenger receptors: CD36, LOX-1, SR-A1, and CXCL16 and cholesterol efflux proteins: ATP-binding cassette transporter (ABC) A1 and G1, and 27-hydroxylase were detected. The adhesion of monocytes to cultured endothelial cells with/ without COX-2 inhibitors/NSAIDs was also analyzed. The presence of celecoxib and rofecoxib (at high concentrations) significantly decreased expression of 27-hydroxylase and ABCA1, interfering with normal cholesterol outflow from macrophages. Acetaminophen and the non-specific COX inhibitor naproxen had no significant effect on these proteins. Only celecoxib had a profound effect on the class B scavenger receptor CD36 and the class E receptor LOX1. We demonstrate that in contrast to celecoxib, rofecoxib and naproxen increased adhesive properties of monocytes to endothelial cells. This work might contribute to our understanding of multiple mechanisms underlying elevated cardiovascular risk upon the use of COX-2 inhibitors and uncover new possibilities to enhance the safety profile of existing COX-2 inhibitors.

Comparative analysis and modeling of the severity of steatohepatitis in DDC-treated mouse strains

Background

Non-alcoholic fatty liver disease (NAFLD) has a broad spectrum of disease states ranging from mild steatosis characterized by an abnormal retention of lipids within liver cells to steatohepatitis (NASH) showing fat accumulation, inflammation, ballooning and degradation of hepatocytes, and fibrosis. Ultimately, steatohepatitis can result in liver cirrhosis and hepatocellular carcinoma.

Methodology and Results

In this study we have analyzed three different mouse strains, A/J, C57BL/6J, and PWD/PhJ, that show different degrees of steatohepatitis when administered a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) containing diet. RNA-Seq gene expression analysis, protein analysis and metabolic profiling were applied to identify differentially expressed genes/proteins and perturbed metabolite levels of mouse liver samples upon DDC-treatment. Pathway analysis revealed alteration of arachidonic acid (AA) and S-adenosylmethionine (SAMe) metabolism upon other pathways. To understand metabolic changes of arachidonic acid metabolism in the light of disease expression profiles a kinetic model of this pathway was developed and optimized according to metabolite levels. Subsequently, the model was used to study in silico effects of potential drug targets for steatohepatitis.

Conclusions

We identified AA/eicosanoid metabolism as highly perturbed in DDC-induced mice using a combination of an experimental and in silico approach. Our analysis of the AA/eicosanoid metabolic pathway suggests that 5-hydroxyeicosatetraenoic acid (5-HETE), 15-hydroxyeicosatetraenoic acid (15-HETE) and prostaglandin D2 (PGD2) are perturbed in DDC mice. We further demonstrate that a dynamic model can be used for qualitative prediction of metabolic changes based on transcriptomics data in a disease-related context. Furthermore, SAMe metabolism was identified as being perturbed due to DDC treatment. Several genes as well as some metabolites of this module show differences between A/J and C57BL/6J on the one hand and PWD/PhJ on the other.

Naproxen induces type X collagen expression in human bone-marrow-derived mesenchymal stem cells through the upregulation of 5-lipoxygenase

Several studies have shown that type X collagen (COL X), a marker of late-stage chondrocyte hypertrophy, is expressed in mesenchymal stem cells (MSCs) from osteoarthritis (OA) patients. We recently found that Naproxen, but not other nonsteroidal anti-inflammatory drugs (NSAIDs) (Ibuprofen, Celebrex, Diclofenac), can induce type X collagen gene (COL10A1) expression in bone-marrow-derived MSCs from healthy and OA donors. In this study we determined the effect of Naproxen on COL X protein expression and investigated the intracellular signaling pathways that mediate Naproxen-induced COL10A1 expression in normal and OA hMSCs. MSCs of OA patients were isolated from aspirates from the intramedullary canal of donors (50-80 years of age) undergoing hip replacement surgery for OA and were treated with or without Naproxen (100 μg/mL). Protein expression and phosphorylation were determined by immunoblotting using specific antibodies (COL X, p38 mitogen-activated protein kinase [p38], phosphorylated-p38, c-Jun N-terminal kinase [JNK], phosphorylated-JNK, extracellular signal-regulated kinase [ERK], and phosphorylated-ERK). Real-time reverse transcription polymerase chain reaction (RT-PCR) was performed to determine the expression of COL10A1 and Runt-related transcription factor 2 gene (Runx2). Our results show that Naproxen significantly stimulated COL X protein expression after 72 h of exposure both in normal and OA hMSCs. The basal phosphorylation of mitogen-activated protein kinases (MAPKs) (ERK, JNK, and p38) in OA hMSCs was significantly higher than in normal. Naproxen significantly increased the MAPK phosphorylation in normal and OA hMSCs. NSAID cellular effects include cyclooxygenase, 5-lipoxygenase, and p38 MAPK signaling pathways. To investigate the involvement of these pathways in the Naproxen-induced COL10A1 expression, we incubated normal and OA hMSCs with Naproxen with and without inhibitors of ERK (U0126), JNK (BI-78D3), p38 (SB203580), and 5-lipoxygenase (MK-886). Our results showed that increased basal COL10A1 expression in OA hMSCs was significantly suppressed in the presence of JNK and p38 inhibitors, whereas Naproxen-induced COL10A1 expression was suppressed by 5-lipoxygenase inhibitor. This study shows that Naproxen induces COL X both at transcriptional and translational levels in normal and OA hMSCs. Elevated basal COL10A1 expression in OA hMSCs is probably through the activation of MAPK pathway and Naproxen-induced COL10A1 expression is through the increased 5-lipoxygenase signaling.

Discovery of potential anti-inflammatory drugs: diaryl-1,2,4-triazoles bearing N-hydroxyurea moiety as dual inhibitors of cyclooxygenase-2 and 5-lipoxygenase

A series of hybrids from diaryl-1,2,4-triazole and hydroxamic acid or N-hydroxyurea were synthesized and evaluated as novel anti-inflammatory agents. The biological data showed that (i) all the compounds showed dual COX-2/5-LOX inhibitory activities in vitro, and 15e showed optimal inhibitory activities (COX-2: IC50 = 0.15 μM, 5-LOX: IC50 = 0.85 μM), (ii) 15e selectively inhibited COX-2 relative to COX-1 with selectivity index (SI = 0.012) comparable to celecoxib (SI = 0.015), (iii) 15e exhibited potent anti-inflammatory activity (inhibition: 54.1%) which was comparable to the reference drug celecoxib (inhibition: 46.7%) in a xylene-induced ear edema assay, and (iv) 15e displayed promising analgesic activity in acetic acid-induced writhing response and hot-plate assay. Finally, a molecular modeling study revealed the binding interactions of 15e with COX-2 and 5-LOX. Our findings suggest that 15e may be a promising anti-inflammatory agent for further evaluation.

Current perspectives in NSAID-induced gastropathy

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most highly prescribed drugs in the world. Their analgesic, anti-inflammatory, and antipyretic actions may be beneficial; however, they are associated with severe side effects including gastrointestinal injury and peptic ulceration. Though several approaches for limiting these side effects have been adopted, like the use of COX-2 specific drugs, comedication of acid suppressants like proton pump inhibitors and prostaglandin analogs, these alternatives have limitations in terms of efficacy and side effects. In this paper, the mechanism of action of NSAIDs and their critical gastrointestinal complications have been reviewed. This paper also provides the information on different preventive measures prescribed to minimize such adverse effects and analyses the new suggested strategies for development of novel drugs to maintain the anti-inflammatory functions of NSAIDs along with effective gastrointestinal protection.

ZLJ-6, a novel COX/5-LOX inhibitor, attenuates TNF-α-induced endothelial E-selectin, ICAM-1 and VCAM-1 expression and monocyte-endothelial interactions via a COX/5-LOX-independent mechanism

Nonsteroidal anti-inflammatory drugs (NSAIDs) are previously found to possess prostaglandin and leukotriene-independent anti-inflammatory effect. The aim of the present study was to investigate the prostaglandin and leukotriene-independent anti-inflammatory effect of an imidazolone COX/5-LOX inhibitor ZLJ-6 and the underlying mechanism. Pretreatment human umbilical vein endothelial cells (HUVECs) with ZLJ-6 (3, 10 and 30 μM) concentration-dependently decreased TNF-α-induced monocyte-endothelial interactions in both static and dynamic conditions whereas no effect was found after pretreatment with the COX-2 inhibitor celecoxib (30 μM), 5-LOX inhibitor zileuton (30 μM) and the combination of them. ZLJ-6 also attenuated expression of E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cytoadhesion molecule-1 (VCAM-1) on TNF-α-induced HUVECs. A further analysis indicated that ZLJ-6 attenuated TNF-α-induced nuclear translocation of NF-κB, IκB phosphorylation, IκB kinase β (IKKβ) activity, and subsequent NF-κB-DNA complex formation, suggesting that NF-κB pathway was involved in TNF-α-induced inflammation. However, ZLJ-6 did not affect TNF-α-induced extracellular signal-regulated kinases (ERK1/2), c-Jun N-terminal kinases (JNK) and p38 phosphorylation. Taken together, our results indicated that ZLJ-6 potently inhibited TNF-α-induced monocyte-endothelial interactions and adhesion molecule (E-selectin, ICAM-1 and VCAM-1) expression and these effects were mediated by NF-κB signaling pathway rather than its primary pharmacological target COX-2 or 5-LOX.

Nuclear factor-kappa β regulates Notch signaling in production of proinflammatory cytokines and nitric oxide in murine BV-2 microglial cells

Microglial cells exhibit Notch-1 signaling expression which is enhanced upon activation. We reported previously that enhanced Notch-1 expression in activated microglia modulates production of proinflammatory cytokines and nitric oxide (NO). Furthermore, Notch-1 modulates transcription factor nuclear factor-kappa B (NF-κB). This study was aimed to investigate if NF-κB reciprocally modulates Notch signaling in BV-2 cells. In this connection, the cells were pretreated with caffeic acid phenethyl ester (Cape) followed by stimulating the cells with lipopolysaccharide (LPS). Cape+LPS treatment resulted in reduced translocation of NF-κB into the nucleus. Concomitantly, NF-κB DNA binding activity and the mRNA and protein expression levels of NF-κB/p65, Notch-1, intracellular domain of Notch-1 receptor (NICD), Hes-1, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) along with nitrite level were significantly reduced. Additionally, flow cytometry analysis showed a decrease in expression levels of NF-κB/p65, Notch-1, NICD but an increase in that of signal transducers and activators of transcription 3 (Stat3). Furthermore, nuclear Hes-1, phosphorylated Stat3 (p-Stat3) and recombination signal-binding protein 1 for J-Kappa (RBP-JK) expression levels were significantly suppressed. The present results suggest that Cape inhibits NF-κB activation through suppressing its interaction with DNA. Cape-induced reduction of Hes-1 may be attributed to decreased interaction between NICD and RBP-JK whose levels were reduced concurrently. Hes-1 reduction may lead to decreased production of inflammatory cytokines and NO. It is concluded that NF-κB can modulate Notch-1 signaling. Both pathways operate synergistically for production of proinflammatory cytokines and NO in activated microglia.

Nuclear factor-κB/p65 responds to changes in the Notch signaling pathway in murine BV-2 cells and in amoeboid microglia in postnatal rats treated with the γ-secretase complex blocker DAPT

Microglial cells constitutively express Notch-1 and nuclear factor-kappaB/p65 (NF-kappaB/p65), and both pathways modulate production of inflammatory mediators. This study sought to determine whether a functional relationship exists between them and, if so, to investigate whether they synergistically regulate common microglial cell functions. By immunofluorescence labeling, real-time polymerase chain reaction (RT-PCR), flow cytometry, and Western blot, BV-2 cells exhibited Notch-1 and NF-kappaB/p65 expression, which was significantly up-regulated in cells challenged with lipopolysaccharide (LPS). This was coupled with an increase in expression of Hes-1, tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta). In BV-2 cells pretreated with N-[N-(3,5-difluorophenacetyl)-1-alany1]-S-phenyglycine t-butyl ester (DAPT), a gamma-secretase inhibitor, followed by LPS stimulation, Notch-1 expression level was enhanced but that of all other markers was suppressed. Additionally, Hes-1 expression and NF-kappaB nuclear translocation decreased as shown by flow cytometry. Notch-1's modulation of NF-kappaB/p65 was also evidenced in amoeboid microglial cells (AMC) in vivo. In 5-day-old rats given intraperitoneal injections of LPS, Notch-1, NF-kappaB/p65, TNF-alpha, and IL-1beta immunofluorescence in AMC was markedly enhanced. However, in rats given an intraperitoneal injection of DAPT prior to LPS, Notch-1 labeling was augmented, but that of TNF-alpha and IL-1beta was reduced. The results suggest that blocking of Notch-1 activation with DAPT would reduce the level of its downstream end product Hes-1 along with suppression of NF-kappaB/p65 translocation, resulting in suppressed production of proinflammatory cytokines. It is concluded that Notch-1 signaling can trans-activate NF-kappaB/p65 by amplifying NF-kappaB/p65-dependent proinflammatory functions in activated microglia.

Chebulagic acid, a COX-LOX dual inhibitor isolated from the fruits of Terminalia chebula Retz., induces apoptosis in COLO-205 cell line

ETHNOPHARMACOLOGICAL RELEVANCE

Terminalia chebula has an esteemed origin in Indian mythology; its fruits are used to treat many diseases such as digestive, diabetes, colic pain, chronic cough, sore throat, asthma, etc.

AIM OF THE STUDY

The water or ethanolic extracts of the fruits were reported to have anti-oxidant, anti-inflammatory, anti-cancer and radio-protector properties. The present study is to isolate and identify the compounds that inhibit COX and 5-LOX, the key enzymes involved in inflammation and carcinogenesis.

MATERIALS AND METHODS

The ethanolic extract of the fruits was fractionated by RP-HPLC and fractions were tested for enzyme inhibition activity against COX and 5-LOX. One of the fractionated compounds showed potent dual inhibition against COX and 5-LOX. It was identified as chebulagic acid by LC-MS, NMR and IR analyses. The chebulagic acid was also tested for anti-proliferative activity.

RESULTS

Chebulagic acid showed potent COX-LOX dual inhibition activity with IC(50) values of 15+/-0.288, 0.92+/-0.011 and 2.1+/-0.057 microM for COX-1, COX-2 and 5-LOX respectively. It also showed anti-proliferative activity against HCT-15, COLO-205, MDA-MB-231, DU-145 and K562 cell lines. Further mechanistic studies on COLO-205 cells revealed induction of apoptosis by chebulagic acid.

CONCLUSIONS

Chebulagic acid, a COX-2 and 5-LOX dual inhibitor isolated from the fruits of Terminalia chebula, induces apoptosis in COLO-205 cells.

Diaryl-dithiolanes and -isothiazoles: COX-1/COX-2 and 5-LOX-inhibitory, *OH scavenging and anti-adhesive activities

Three series of non-steroidal anti-inflammatory drugs (NSAIDs) inhibiting the cyclooxygenase/5-lipoxygenase (COX/5-LOX) pathways as such as formation of hydroxyl radicals and adhesion were prepared: 4,5-diaryl isothiazoles, 4,5-diaryl 3H-1,2-dithiole-3-thiones and 4,5-diaryl 3H-1,2-dithiole-3-ones. The aim of the present study was to develop substances which can intervene into the inflammatory processes via different mechanisms of action as multiple target non-steroidal anti-inflammatory drugs (MTNSAIDs) with increased anti-inflammatory potential. The current lead 11a was evaluated in COX-1/2, 5-LOX and (*)OH scavenging in vitro assays and in a static adhesion assay where it proved to inhibit adhesion. Moreover, 11a treatment attenuated expression of macrophage adhesion molecule-1 (Mac-1) on extravasated polymorphonuclear leukocytes (PMNs) which indicates that the activation was reduced. The assays used are predictive for the in vivo efficacy of test compounds as shown for 11a in a peritonitis model of acute inflammation in mice. Thus, the novel 5-LOX/COX and (*)OH inhibitor 11a possesses anti-inflammatory activity that, in addition to COX/5-LOX inhibition, implicates effects on leukocyte-endothelial interactions.

Cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) selectivity of COX inhibitors

In vitro evaluations of the selectivity of COX inhibitors are based on a great variety of experimental protocols. As a result, data available on cyclooxygenase (COX)-1/COX-2/5- lipoxygenase (LOX) selectivity of COX inhibitors lack consistency. We, therefore, performed a systematic analysis of the COX-1/COX-2/5-LOX selectivity of 14 compounds with selective COX inhibitory activity (Coxibs). The compounds belonged to different structural classes and were analyzed employing the well-recognized whole-blood assay. 5-LOX activity was also tested on isolated human polymorphonuclear leukocytes. Among COX inhibitors, celecoxib and ML-3000 (licofelone) inhibited 5-LOX in human neutrophils at micromolar ranges. Surprisingly, ML-3000 had no effect on 5-LOX product synthesis in whole-blood assay. In addition, we could show that inhibition of COX pathways did not increase the transformation of arachidonic acid by the 5-LOX pathway.

Upregulation of ICAM-1 expression in bronchial epithelial cells by airway secretions in bronchiectasis

The airway epithelium participates in chronic airway inflammation by expressing adhesion molecules that mediate the transmigration of neutrophils into the inflamed airways. We hypothesize that, in patients with bronchiectasis, cytokines in their bronchial secretions enhance the expression of intercellular cell adhesion molecule (ICAM-1) in the bronchial epithelium and thus contribute to sustained recruitment of neutrophils into the inflamed airways. In the present study, we investigated the effect of bronchial secretions on the regulation of ICAM-1 in bronchial epithelial cells, and its modulation by pharmacologic agents. The expression of ICAM-1 mRNA and protein in human bronchial epithelial cells upon exposure to sputum sol from subjects with bronchiectasis were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and ELISA, respectively. Modulating effects of dexamethasone, ibuprofen, MK-663 or triptolide on ICAM-1 regulation were investigated in vitro. We demonstrated that changes in ICAM-1 expression correlated with levels of TNF-alpha in the sputum sol, and treatment of sol samples with TNF-alpha antibodies attenuated both the increase in ICAM-1 mRNA and protein. The role of TNF-alpha was further demonstrated when TNF-alpha elicited dose dependent increase in ICAM-1 expression. The sputum effect could also be suppressed dose-dependently by pre-incubation of bronchial epithelial cells with dexamethasone, ibuprofen, MK-663 or triptolide. Evidence is thus provided for the upregulation of bronchial epithelial ICAM-1 expression by airway secretions in bronchiectasis and a specific role for TNF-alpha in the secretions. The success of drug attenuation of this upregulation provides insight into possible therapeutic paradigms in the management of the disease.

Investigations concerning the COX/5-LOX inhibiting and hydroxyl radical scavenging potencies of novel 4,5-diaryl isoselenazoles

The aim of this study was to investigate 4,5-diaryl isoselenazoles as multiple target non-steroidal anti-inflammatory drugs (MTNSAIDs) which can intervene into the inflammatory processes via different mechanisms of action creating a new class of compounds. Here we describe the synthesis of COX/LOX inhibitors which additionally reduce the level of reactive oxygen species, such as hydroxyl radicals which are well known for supporting inflammation processes in Parkinson's disease, Alzheimer's disease and rheumatoid arthritis.

Drug-induced immunomodulation to affect the development and progression of atherosclerosis: a new opportunity?

Inflammation and cytokine pathways are crucial for the development and progression of atherosclerotic lesions. In this review, the hypothesis that immunomodulatory drugs provide a possible therapeutic modality for cardiovascular disease is evaluated. Therefore, after a short overview of the specific inflammatory pathways involved in atherosclerosis, literature on the effect of several immunomodulatory drugs, such as nonsteroidal anti-inflammatory drugs, specific cyclooxygenase inhibitors and immunosuppressive drugs, used currently in the prevention of rejection after organ transplant, on the development and progression of atherosclerosis is reviewed. In addition, the pleiotropic immunomodulatory effect of two established cardiovascular drugs (angiotensin-converting enzyme inhibitors and statins) is discussed.

Dynamic simulations on the arachidonic acid metabolic network

Drug molecules not only interact with specific targets, but also alter the state and function of the associated biological network. How to design drugs and evaluate their functions at the systems level becomes a key issue in highly efficient and low-side-effect drug design. The arachidonic acid metabolic network is the network that produces inflammatory mediators, in which several enzymes, including cyclooxygenase-2 (COX-2), have been used as targets for anti-inflammatory drugs. However, neither the century-old nonsteriodal anti-inflammatory drugs nor the recently revocatory Vioxx have provided completely successful anti-inflammatory treatment. To gain more insights into the anti-inflammatory drug design, the authors have studied the dynamic properties of arachidonic acid (AA) metabolic network in human polymorphous leukocytes. Metabolic flux, exogenous AA effects, and drug efficacy have been analyzed using ordinary differential equations. The flux balance in the AA network was found to be important for efficient and safe drug design. When only the 5-lipoxygenase (5-LOX) inhibitor was used, the flux of the COX-2 pathway was increased significantly, showing that a single functional inhibitor cannot effectively control the production of inflammatory mediators. When both COX-2 and 5-LOX were blocked, the production of inflammatory mediators could be completely shut off. The authors have also investigated the differences between a dual-functional COX-2 and 5-LOX inhibitor and a mixture of these two types of inhibitors. Their work provides an example for the integration of systems biology and drug discovery.

Licofelone, a balanced inhibitor of cyclooxygenase and 5-lipoxygenase, reduces inflammation in a rabbit model of atherosclerosis

Licofelone, a dual anti-inflammatory drug that inhibits 5-lipoxygenase (LOX) and cyclooxygenase (COX) enzymes, may have a better cardiovascular profile that cycloxygenase-2 inhibitors due to cycloxygenase-1 blockade-mediated antithrombotic effect and a better gastrointestinal tolerability. We examined the anti-inflammatory effect of licofelone on atherosclerotic lesions as well as in isolated neutrophils from whole blood of rabbits compared with a selective inhibitor of COX-2, rofecoxib. We also assessed the antithrombotic effect of licofelone in rabbit platelet-rich plasma. For this purpose, 30 rabbits underwent injury of femoral arteries, and they were randomized to receive 10 mg/kg/day licofelone or 5 mg/kg/day rofecoxib or no treatment during 4 weeks with atherogenic diet in all cases. Ten healthy rabbits were used as controls. Neutrophils and platelets were isolated from peripheral blood of rabbits for ex vivo studies. Licofelone reduced intima/media ratio in injured arteries, the macrophages infiltration in the neointimal area, monocyte chemoattractant protein-1 (MCP-1) gene expression, and the activation of nuclear factor-kappaB in rabbit atheroma. Moreover, licofelone inhibited COX-2 and 5-LOX protein expression in vascular lesions. Rofecoxib only diminished COX-2 protein expression and MCP-1 gene expression in vascular atheroma. Prostaglandin E(2) in rabbit plasma was attenuated by both drugs. Licofelone almost abolished 5-LOX activity by inhibiting leukotriene B4 generation in rabbit neutrophils and prevented platelet thromboxane B2 production from whole blood. Licofelone reduces neointimal formation and inflammation in an atherosclerotic rabbit model more markedly than rofecoxib. This effect, together with the antiplatelet activity of licofelone, suggests that this drug may have a favorable cardiovascular profile.

New analogues of butylated hydroxytoluene as anti-inflammatory and antioxidant agents

Amine or amide derivatives bearing the 2,6-di-tert-butyl phenol moiety are synthesised. Almost all are antioxidants, reduce acute inflammation and inhibit COX-1 and lipoxygenase activity. The most potent anti-inflammatory, COX-1 inhibitor and antioxidant agent, with low toxicity, is 2,6-di-tert-butyl-4-thiomorpholin-4-ylmethyl-phenol.