Licofelone--clinical update on a novel LOX/COX inhibitor for the treatment of osteoarthritis

Discovery of new thymol-3,4-disubstituted thiazole hybrids as dual COX-2/5-LOX inhibitors with in vivo proof

New thymol-3,4-disubstitutedthiazole hybrids were synthesised as dual COX-2/5-LOX inhibitors. Compounds 6b, 6d, 6e, and 6f displayed in vitro inhibitory activity against COX-2 (IC50= 0.037, 0.042, 0.046, and 0.039 µM) nearly equal to celecoxib (IC50= 0.045 µM). 6b, 6d, and 6f showed SI (379, 341, and 374, respectively) higher than that of celecoxib (327). 6a-l elicited in vitro 5-LOX inhibitory activity higher than quercetin. 6a-f, 6i-l, 7a, and 7c possessed in vivo inhibition of formalin induced paw edoema higher than celecoxib. 6a, 6b, 6f, 6h-l, and 7b showed gastrointestinal safety profile as celecoxib and diclofenac sodium in the population of fasted rats. Induced fit docking and molecular dynamics simulation predicted good fitting of 6b and 6f without changing the packing and globularity of the apo protein. In conclusion, 6b and 6f achieved the target goal as multitarget inhibitors of inflammation.

Fighting age-related orthopedic diseases: focusing on ferroptosis

Ferroptosis, a unique type of cell death, is characterized by iron-dependent accumulation and lipid peroxidation. It is closely related to multiple biological processes, including iron metabolism, polyunsaturated fatty acid metabolism, and the biosynthesis of compounds with antioxidant activities, including glutathione. In the past 10 years, increasing evidence has indicated a potentially strong relationship between ferroptosis and the onset and progression of age-related orthopedic diseases, such as osteoporosis and osteoarthritis. Therefore, in-depth knowledge of the regulatory mechanisms of ferroptosis in age-related orthopedic diseases may help improve disease treatment and prevention. This review provides an overview of recent research on ferroptosis and its influences on bone and cartilage homeostasis. It begins with a brief overview of systemic iron metabolism and ferroptosis, particularly the potential mechanisms of ferroptosis. It presents a discussion on the role of ferroptosis in age-related orthopedic diseases, including promotion of bone loss and cartilage degradation and the inhibition of osteogenesis. Finally, it focuses on the future of targeting ferroptosis to treat age-related orthopedic diseases with the intention of inspiring further clinical research and the development of therapeutic strategies.

Two-Dimensional and Three-Dimensional Cartilage Model Platforms for Drug Evaluation and High-Throughput Screening Assays

Osteoarthritis (OA) is a severely painful and debilitating disease of the joint, which brings about degradation of the articular cartilage and currently has few therapeutic solutions. Two-dimensional (2D) high-throughput screening (HTS) assays have been widely used to identify candidate drugs with therapeutic potential for the treatment of OA. A number of small molecules which improve the chondrogenic differentiation of progenitor cells for tissue engineering applications have also been discovered in this way. However, due to the failure of these models to accurately represent the native joint environment, the efficacy of these drugs has been limited in vivo. Screening systems utilizing three-dimensional (3D) models, which more closely reflect the tissue and its complex cell and molecular interactions, have also been described. However, the vast majority of these systems fail to recapitulate the complex, zonal structure of articular cartilage and its unique cell population. This review summarizes current 2D HTS techniques and addresses the question of how to use existing 3D models of tissue-engineered cartilage to create 3D drug screening platforms with improved outcomes. Impact statement Currently, the use of two-dimensional (2D) screening platforms in drug discovery is common practice. However, these systems often fail to predict efficacy in vivo, as they do not accurately represent the complexity of the native three-dimensional (3D) environment. This article describes existing 2D and 3D high-throughput systems used to identify small molecules for osteoarthritis treatment or in vitro chondrogenic differentiation, and suggests ways to improve the efficacy of these systems based on the most recent research.

The Importance of Rhodanine Scaffold in Medicinal Chemistry: A Comprehensive Overview

After the clinical use of epalrestat that contains a rhodanine ring, in type II diabetes mellitus and diabetic complications, rhodanin-based compounds have become an important class of heterocyclic in the field of medicinal chemistry. Various modifications to the rhodanine ring have led to a broad spectrum of biological activity of these compounds. Synthesis of rhodanine derivatives, depended on advenced throughput scanning hits, frequently causes potent and selective modulators of targeted enzymes or receptors, which apply their pharmacological activities through different mechanisms of action. Rhodanine-based compounds will likely stay a privileged scaffold in drug discovery because of different probability of chemical modifications of the rhodanine ring. We have, therefore reviewed their biological activities and structure activity relationship.

Involvement of N-Methyl-D-Aspartate Receptors in the Anticonvulsive Effects of Licofelone on Pentylenetetrazole-Induced Clonic Seizure in Mice

BACKGROUND AND PURPOSE

Licofelone is a dual 5-lipoxygenase/cyclooxygenase inhibitor, with well-documented anti-inflammatory and analgesic effects, which is used for treatment of osteoarthritis. Recent preclinical studies have also suggested neuroprotective and anti-oxidative properties of this drug in some neurological conditions such as seizure and epilepsy. We have recently demonstrated a role for nitric oxide (NO) signaling in the anti-epileptic activity of licofelone in two seizure models in rodents. Given the important role of N-methyl-D-aspartate receptors (NMDARs) activation in the NO production and its function in the nervous system, in the present study, we further investigated the involvement of NMDAR in the effects of licofelone (1, 3, 5, 10, and 20 mg/kg, intraperitoneal [i.p.]) in an in vivo model of seizure in mice.

METHODS

Clonic seizures were induced in male NMRI mice by intravenous administration of pentylenetetrazol (PTZ).

RESULTS

Acute administration of licofelone exerted anticonvulsant effects at 10 (p<0.01) and 20 mg/kg (p<0.001). A combined treatment with sub-effective doses of the selective NMDAR antagonist MK-801 (0.05 mg/kg, i.p.) and licofelone (5 mg/kg, i.p.) significantly (p<0.001) exerted an anticonvulsant effect on the PTZ-induced clonic seizures in mice. Notably, pre-treatment with the NMDAR co-agonist D-serine (30 mg/kg, i.p.) partially hindered the anticonvulsant effects of licofelone (20 mg/kg).

CONCLUSIONS

Our data suggest a possible role for the NMDAR in the anticonvulsant effects of licofelone on the clonic seizures induced by PTZ in mice.

Metabolism pathways of arachidonic acids: mechanisms and potential therapeutic targets

The arachidonic acid (AA) pathway plays a key role in cardiovascular biology, carcinogenesis, and many inflammatory diseases, such as asthma, arthritis, etc. Esterified AA on the inner surface of the cell membrane is hydrolyzed to its free form by phospholipase A2 (PLA2), which is in turn further metabolized by cyclooxygenases (COXs) and lipoxygenases (LOXs) and cytochrome P450 (CYP) enzymes to a spectrum of bioactive mediators that includes prostanoids, leukotrienes (LTs), epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid (diHETEs), eicosatetraenoic acids (ETEs), and lipoxins (LXs). Many of the latter mediators are considered to be novel preventive and therapeutic targets for cardiovascular diseases (CVD), cancers, and inflammatory diseases. This review sets out to summarize the physiological and pathophysiological importance of the AA metabolizing pathways and outline the molecular mechanisms underlying the actions of AA related to its three main metabolic pathways in CVD and cancer progression will provide valuable insight for developing new therapeutic drugs for CVD and anti-cancer agents such as inhibitors of EETs or 2J2. Thus, we herein present a synopsis of AA metabolism in human health, cardiovascular and cancer biology, and the signaling pathways involved in these processes. To explore the role of the AA metabolism and potential therapies, we also introduce the current newly clinical studies targeting AA metabolisms in the different disease conditions.

Structure-based, multi-targeted drug discovery approach to eicosanoid inhibition: Dual inhibitors of mPGES-1 and 5-lipoxygenase activating protein (FLAP)

BACKGROUND

Due to the importance of both prostaglandins (PGs) and leukotrienes (LTs) as pro-inflammatory mediators, and the potential for eicosanoid shunting in the presence of pathway target inhibitors, we have investigated an approach to inhibiting the formation of both PGs and LTs as part of a multi-targeted drug discovery effort.

METHODS

We generated ligand-protein X-ray crystal structures of known inhibitors of microsomal prostaglandin E2 synthase-1 (mPGES-1) and the 5-Lipoxygenase Activating Protein (FLAP), with their respective proteins, to understand the overlapping pharmacophores. We subsequently used molecular modeling and structure-based drug design (SBDD) to identify hybrid structures intended to inhibit both targets.

RESULTS

This work enabled the preparation of compounds 4 and 5, which showed potent in vitro inhibition of both targets.

SIGNIFICANCE

Our findings enhance the structural understanding of mPGES-1 and FLAP's unique ligand binding pockets and should accelerate the discovery of additional dual inhibitors for these two important integral membrane protein drug targets.

Diversified Thiazole Substituted Coumarins and Chromones as Non- Cytotoxic ROS and NO Inhibitors

Background:

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, aspirin, indomethacin, flufenamic acid and phenylbutazone are used to treat most of the inflammatory disorders. These NSAIDs are also associated with serious side effects including gastric ulceration, nephrotoxicity, and bleeding, mainly due to acidic nature. Hence, there is a need to identify highly potent and safer treatment for inflammatory disorders.

Methods:

Herein, synthetic hydrazinyl thiazole substituted coumarins and chromones 1-48 were evaluated for ROS inhibitory activity. ROS were generated from zymosan activated whole blood phagocytes.

Results:

Among all tested compounds, compounds 1 (IC50 = 38.3 ± 7.1 μM), 2 (IC50 = 5.7 ± 0.2 μM), 5 (IC50 = 28.3 ± 3.5 μM), 23 (IC50 = 12.5 ± 3.1 μM), 27 (IC50 = 32.8 ± 1.1 μM), 39 (IC50 = 20.2 ± 1.6 μM), and 42 (IC50 = 43.2 ± 3.8 μM) showed potent ROS inhibition as compared to standard ibuprofen (IC50 = 54.3 ± 1.9 μM). Whereas, compounds 3 (IC50 = 134.7 ± 1.0 μM), 16 (IC50 = 75.4 ± 7.2 μM), 24 (IC50 = 102.4 ± 1.0 μM), and 31 (IC50 = 86.6 ± 1.5 μM) were found to be moderately active. Compounds 1, 2, 5, 23, 27, 39, and 42, having potent ROS inhibitory activity were also screened for their nitric oxide (NO) inhibition. Cytotoxicity was also checked for all active compounds on NIH-3T3 cell line. Cyclohexamide (IC50 = 0.13 ± 0.02 μM) was used as standard.

Conclusion:

Identified active compounds from these libraries may serve as lead candidates for future research in order to obtain a more potent, and safer anti-inflammatory agent.

Modulation of smoke-induced DNA and microRNA alterations in mouse lung by licofelone, a triple COX-1, COX-2 and 5-LOX inhibitor

Chronic inflammation plays a crucial role in the carcinogenesis process and, in particular, in smoking-related carcinogenesis. Therefore, anti-inflammatory agents provide an interesting perspective in the prevention of smoking-associated cancers. Among nonsteroidal anti-inflammatory drugs (NSAIDs), licofelone is a triple inhibitor of both cyclooxygenases (COX-1 and COX-2) and of 5-lipooxygenase (5-LOX) that has shown some encouraging results in cancer prevention models. We previously showed that the dietary administration of licofelone, starting after weanling, to Swiss H mice exposed for 4 months to mainstream cigarette smoke since birth attenuated preneoplastic lesions of inflammatory nature in both lung and urinary tract, and had some effects on the yield of lung tumors at 7.5 months of age. The present study aimed at evaluating the early modulation by licofelone of pulmonary DNA and RNA alterations either in smoke-free or smoke-exposed H mice after 10 weeks of exposure. Licofelone protected the mice from the smoke-induced loss of body weight and significantly attenuated smoke-induced nucleotide alterations by decreasing the levels of bulky DNA adducts and 8-hydroxy-2'-deoxyguanosine in mouse lung. Moreover, the drug counteracted dysregulation by smoke of several pulmonary microRNAs involved in stress response, inflammation, apoptosis, and oncogene suppression. However, even in smoke-free mice administration of the drug had significant effects on a broad panel of microRNAs and, as assessed in a subset of mice used in a parallel cancer chemoprevention study, licofelone even enhanced the smoke-induced systemic genotoxic damage after 4 months of exposure. Therefore, caution should be paid when administering licofelone to smokers for long periods.

Druggable Prostanoid Pathway

Prostanoids (prostaglandins, prostacyclin and thromboxane) belong to the oxylipin family of biologically active lipids generated from arachidonic acid (AA). Protanoids control numerous physiological and pathological processes. Cyclooxygenase (COX) is a rate-limiting enzyme involved in the conversion of AA into prostanoids. There are two COX isozymes: the constitutive COX-1 and the inducible COX-2. COX-1 and COX-2 have similar structures, catalytic activities, and subcellular localizations but differ in patterns of expression and biological functions. Non-selective COX-1/2 or traditional, non-steroidal anti-inflammatory drugs (tNSAIDs) target both COX isoforms and are widely used to relieve pain, fever and inflammation. However, the use of NSAIDs is associated with various side effects, particularly in the gastrointestinal tract. NSAIDs selective for COX-2 inhibition (coxibs) were purposefully designed to spare gastrointestinal toxicity, but predisposed patients to increased cardiovascular risks. These health complications from NSAIDs prompted interest in the downstream effectors of the COX enzymes as novel drug targets. This chapter describes various safety issues with tNSAIDs and coxibs, and discusses the current development of novel classes of drugs targeting the prostanoid pathway, including nitrogen oxide- and hydrogen sulfide-releasing NSAIDs, inhibitors of prostanoid synthases, dual inhibitors, and prostanoid receptor agonists and antagonists.

5-Lipoxygenase as a drug target: A review on trends in inhibitors structural design, SAR and mechanism based approach

The most common inflammatory disease of the airways is asthma among children affecting around 235 million people worldwide. 5-Lipoxygenase (5-LOX) is a crucial enzyme which helps in the conversion of arachidonic acid (AA) to leukotrienes (LTs), the lipid mediators. It is associated with several inflammation related disorders such as asthma, allergy, and atherosclerosis. Therefore, it is considered as a promising target against inflammation and asthma. Currently, the only drug against 5-LOX which is available is Zileuton, while a few inhibitors are in clinical trial stages such as Atreleuton and Setileuton. So, there is a dire requirement in the area of progress of novel 5-LOX inhibitors which necessitates an understanding of their structure activity relationship and mode of action. In this review, novel 5-LOX inhibitors reported so far, their structural design, SAR and developmental strategies along with clinical updates are discussed over the last two decades.

Disease-modifying drugs in osteoarthritis: current understanding and future therapeutics

INTRODUCTION

Osteoarthritis (OA) is a leading cause of pain and disability among adults with a current prevalence of around 15% and a predicted prevalence of 35% in 2030 for symptomatic OA. It is increasingly recognized as a heterogeneous multi-faceted joint disease with multi-tissue involvement of varying severity. Current therapeutic regimens for OA are only partially effective and often have significant associated toxicities. There are no disease-modifying drugs approved by the regulatory bodies. Areas covered: We reviewed the opportunities within key OA pathogenetic mechanism: cartilage catabolism/anabolism, pathological remodeling of subchondral bone and synovial inflammation to identify targeted disease-modifying osteoarthritis drugs, based on compounds currently in Phase II and III stages of clinical development in which x-ray and/or MRI was used as the structural outcome with/without symptomatic outcomes according to regulatory requirements. Expert opinion: Given the heterogeneity of the OA disease process and complex overlapping among these phenotypes, a 'one size fits all' approach used in most clinical trials would unlikely be practical and equally effective in all patients, as well as in all anatomical OA sites. On the other hand, it is a challenge to develop a targeted drug with high activity, specificity, potency, and bioavailability in the absence of toxicity for long-term use in this chronic disease of predominantly older adults. Further research and insight into evaluation methods for drug-targeted identification of early OA and specific characterization of phenotypes, improvement of methodological designs, and development/refinement of sensitive imaging and biomarkers will help pave the way to the successful discovery of disease-modifying drugs and the optimal administration strategies in clinical practice.

Clinically Relevant Anti-Inflammatory Agents for Chemoprevention of Colorectal Cancer: New Perspectives

Substantial efforts are underway for prevention of early stages or recurrence of colorectal cancers (CRC) or new polyp formation by chemoprevention strategies. Several epidemiological, clinical and preclinical studies to date have supported the chemopreventive potentials of several targeted drug classes including non-steroidal anti-inflammatory drugs (NSAIDs) (aspirin, naproxen, sulindac, celecoxib, and licofelone), statins and other natural agents—both individually, and in combinations. Most preclinical trials although were efficacious, only few agents entered clinical trials and have been proven to be potential chemopreventive agents for colon cancer. However, there are limitations for these agents that hinder their approval by the food and drug administration for chemoprevention use in high-risk individuals and in patients with early stages of CRC. In this review, we update the recent advancement in pre-clinical and clinical development of selected anti-inflammatory agents (aspirin, naproxen, sulindac, celecoxib, and licofelone) and their combinations for further development as novel colon cancer chemopreventive drugs. We provide further new perspectives from this old research, and insights into precision medicine strategies to overcome unwanted side-effects and overcoming strategies for colon cancer chemoprevention.

Synthesis, anti-inflammatory screening, molecular docking, and COX-1,2/-5-LOX inhibition profile of some novel quinoline derivatives

New quinoline compounds comprising pyrazole scaffold through different amide linkages were synthesized. The synthesized compounds were evaluated for their anti-inflammatory activity. Eight compounds (5c, 11b,c, 12c, 14a,b, 20a and 21a) were found to exhibit promising anti-inflammatory profiles in acute and sub-acute inflammatory models. They were screened for their ulcerogenic activity and none of them showed significant ulcerogenic activity comparable to the reference drug celecoxib and are well tolerated by experimental animals with high safety margin (ALD50 > 0.3 g/kg). Compounds 5c, 11b,c, 12c, 14a,b, 20a and 21a showed significant in vitro LOX inhibitory activity higher than that of zileuton. In vitro COX-1/COX-2 inhibition study revealed that compounds 12c, 14a,b and 20a showed higher selectivity towards COX-2 than COX-1. Among the tested compounds, 12c, 14a and 14b showed the highest inhibitory activity against COX-2 with an IC50 values of 0.1, 0.11 and 0.11 μM respectively. The docking experiments attempted to postulate the binding mode for the most active compounds in the binding site of COX-2 enzymes and confirmed the high selectivity binding towards COX-2 enzyme over COX-1.

Application of Docking Analysis in the Prediction and Biological Evaluation of the Lipoxygenase Inhibitory Action of Thiazolyl Derivatives of Mycophenolic Acid

5-LOX inhibition is among the desired characteristics of anti-inflammatory drugs, while 15-LOX has also been considered as a drug target. Similarity in inhibition behavior between soybean LOX-1 and human 5-LOX has been observed and soybean LOX (sLOX) type 1b has been used for the evaluation of LOX inhibition in drug screening for years. After prediction of LOX inhibition by PASS and docking as well as toxicity by PROTOX and ToxPredict sixteen (E)-N-(thiazol-2-yl)-6-(4-hydroxy-6-methoxy-7-methyl-3-oxo-1,3-dihydroisobenzofuran-5-yl)-4-methylhex-4-enamide derivatives with lengths varying from about 15⁻20 Å were evaluated in vitro for LOX inhibitory action using the soybean lipoxygenase sLOX 1b. Docking analysis was performed using soybean LOX L-1 (1YGE), soybean LOX-3 (1JNQ), human 5-LOX (3O8Y and 3V99) and mammalian 15-LOX (1LOX) structures. Different dimensions of target center and docking boxes and a cavity prediction algorithm were used. The compounds exhibited inhibitory action between 2.5 μΜ and 165 μΜ. Substituents with an electronegative atom at two-bond proximity to position 4 of the thiazole led to enhanced activity. Docking results indicated that the LOX structures 1JNQ, 3V99 and 1LOX can effectively be used for estimation of LOX inhibition and amino acid interactions of these compounds.

Safer anti-inflammatory therapy through dual COX-2/5-LOX inhibitors: A structure-based approach

Inflammatory mediators of the arachidonic acid cascade from cyclooxygenase (COX) and lipoxygenase (LOX) pathways are primarily responsible for many diseases in human beings. Chronic inflammation is associated with the pathogenesis and progression of cancer, arthritis, autoimmune, cardiovascular and neurological diseases. Traditional non-steroidal anti-inflammatory agents (tNSAIDs) inhibit cyclooxygenase pathway non-selectively and produce gastric mucosal damage due to COX-1 inhibition and allergic reactions and bronchospasm resulting from increased leukotriene levels. 'Coxibs' which are selective COX-2 inhibitors cause adverse cardiovascular events. Inhibition of any of these biosynthetic pathways could switch the metabolism to the other, which can lead to fatal side effects. Hence, there is undoubtedly an urgent need for new anti-inflammatory agents having dual mechanism that prevent release of both prostaglandins and leukotrienes. Though several molecules have been synthesized with this objective, their unfavourable toxicity profile prevented them from being used in clinics. Here, this integrative review attempts to identify the promising pharmacophore that serves as dual inhibitors of COX-2/5-LOX enzymes with improved safety profile. A better acquaintance of structural features that balance safety and efficacy of dual inhibitors would be a different approach to the process of understanding and interpreting the designing of novel anti-inflammatory agents.

Multiple target-centric strategy to tame inflammation

Single-target inhibition is an unsatisfactory therapeutic option to treat multifactorial pathologies, brought into limelight 'paradox of inflammation' beside dearth of innovation, rationalizes a shift toward 'multiple-target' design concept in anti-inflammatory research field. To improvise, two platform strategies, drugs mixture or multitarget drugs, are plausible. Dual cyclooxygenase/lipoxygenase inhibitor 'licofelone' developed after the backfire of rofecoxib due to safety concerns has fetched first light of triumph of the latter strategy. As hitting multiple targets in restraint is perhaps more viable strategy rather than single target, this review, outlines the most germane multiple target agents of synthetic and natural origin placing clear advantage in favors of multitarget strategy as real therapeutic solution for inflammation.

Small molecule therapeutics for inflammation-associated chronic musculoskeletal degenerative diseases: Past, present and future

Inflammation-associated chronic musculoskeletal degenerative diseases (ICMDDs) like osteoarthritis and tendinopathy often results in morbidity and disability, with consequent heavy socio-economic burden. Current available therapies such as NSAIDs and glucocorticoid are palliative rather than disease-modifying. Insufficient systematic research data on disease molecular mechanism also makes it difficult to exploit valid therapeutic targets. Small molecules are designed to act on specific signaling pathways and/or mechanisms of cellular physiology and function, and have gradually shown potential for treating ICMDDs. In this review, we would examine and analyze recent developments in small molecule drugs for ICMDDs, suggest possible feasible improvements in treatment modalities, and discuss future research directions.

Drug discovery approaches targeting 5-lipoxygenase-activating protein (FLAP) for inhibition of cellular leukotriene biosynthesis

Leukotrienes are proinflammatory lipid mediators associated with diverse chronic inflammatory diseases such as asthma, COPD, IBD, arthritis, atherosclerosis, dermatitis and cancer. Cellular leukotrienes are produced from arachidonic acid via the 5-lipoxygenase pathway in which the 5-lipoxygenase activating protein, also named as FLAP, plays a critical role by operating as a regulatory protein for efficient transfer of arachidonic acid to 5-lipoxygenase. By blocking leukotriene production, FLAP inhibitors may behave as broad-spectrum leukotriene modulators, which might be of therapeutic use for chronic inflammatory diseases requiring anti-leukotriene therapy. The early development of FLAP inhibitors (i.e. MK-886, MK-591, BAY-X-1005) mostly concentrated on asthma cure, and resulted in promising readouts in preclinical and clinical studies with asthma patients. Following the recent elucidation of the 3D-structure of FLAP, development of new inhibitor chemotypes is highly accelerated, eventually leading to the evolution of many un-drug-like structures into more drug-like entities such as AZD6642 and BI665915 as development candidates. The most clinically advanced FLAP inhibitor to date is GSK2190918 (formerly AM803) that has successfully completed phase II clinical trials in asthmatics. Concluding, although there are no FLAP inhibitors reached to the drug approval phase yet, due to the rising number of indications for anti-LT therapy such as atherosclerosis, FLAP inhibitor development remains a significant research field. FLAP inhibitors reviewed herein are classified into four sub-classes as the first-generation FLAP inhibitors (indole and quinoline derivatives), the second-generation FLAP inhibitors (diaryl-alkanes and biaryl amino-heteroarenes), the benzimidazole-containing FLAP inhibitors and other FLAP inhibitors with polypharmacology for easiness of the reader. Hence, we meticulously summarize how FLAP inhibitors historically developed from scratch to their current advanced state, and leave the reader with a positive view that a FLAP inhibitor might soon reach to the need of patients who may require anti-LT therapy.

Transition-Metal-Free, Atom- and Step-Economic Synthesis of Aminoketopyrrolizines from Benzylamine, Acylethynylpyrroles, and Acylacetylenes

A concise, atom-economic strategy for the synthesis of pyrrolizines with amino and keto substituents has been developed. It includes the following key steps: (i) the base-catalyzed (K₃PO₄/DMSO) addition of a benzylamine to 2-acylethynylpyrroles and (ii) noncatalyzed addition of enaminones obtained to the triple bond of acylacetylenes followed by intramolecular cyclization of the intermediate pentadiendiones thus formed to the target 1-(benzylamino)-2-acyl-3-methylenoacylpyrrolizines.

New benzothiophene derivatives as dual COX-1/2 and 5-LOX inhibitors: synthesis, biological evaluation and docking study

Aim: Simultaneous inhibition of 5-LOX/COX may enhance anti-inflammatory effects and reduce side effects. Hence, synthesis of novel dual inhibitors of 5-LOX/COX is an important strategy for treatment of inflammation. Results/methodology: The target compounds were designed to hybridize benzothiophene scaffold or its bioisostere benzofuran with various anti-inflammatory pharmacophore hetercycles through different atoms spacers. Compounds 4a, 4c, 4d, 5b, 7a, showed significant in vitro LOX inhibitory activity higher than that of meclofenamate sodium. Compounds 4b, 4e, 4f, 5a exhibited significant in vitro COX-2 inhibition higher than celecoxib and in vitro LOX inhibitory activity twice that of reference. These compounds elicited significant in vivo anti-inflammatory activities higher than celecoxib in formalin-induced paw edema test. Compound 4e exhibited gastrointestinal safety profile as celecoxib. The results were also consistent with the docking studies. Conclusion: Compound 4e could be considered as structural lead for the development of a new class of anti-inflammatory agents with better safety profile.

Investigational drugs targeting the prostaglandin E2 signaling pathway for the treatment of inflammatory pain

Non-steroidal anti-inflammatory drugs (NSAID) are the most commonly used drugs for the treatment of pain, inflammation and fever. Although they are effective for a huge number of users, their analgesic properties are not sufficient for several patients and the occurrence of side effects still constitutes a big challenge during long term therapy. Areas covered: This review gives an overview about the first and second generations of NSAIDs (COX1/2 non-selective, COX-2 selective), and their main side effects which gave still an urgent need for safer drugs and for the establishment of novel treatment strategies (improved safety, tolerability, patient convenience). The current developments of a possible third generation NSAID class comprise changes in the formulation of already approved drugs, combination therapies, dual cyclooxygenase-lipoxygenase inhibitors, NO- and H₂S-releasing NSAIDs, prostaglandin synthase inhibitors and EP receptor modulators, respectively. Literature search has been done with PubMed NCBI. Expert opinion: Currently, there is no newly developed drug that is superior to the already approved selective and non-selective NSAIDs. Several novel approaches show promising analgesic efficacy but side effects are still an important problem. Solutions might be constituted by combination therapies allowing administration of lower drug doses or by individualized therapies targeting molecules apart from COX, respectively.

Pharmacological Modulation of Lung Carcinogenesis in Smokers: Preclinical and Clinical Evidence

Many drugs in common use possess pleiotropic properties that make them capable of interfering with carcinogenesis mechanisms. We discuss here the ability of pharmacological agents to mitigate the pulmonary carcinogenicity of mainstream cigarette smoke. The evaluated agents include anti-inflammatory drugs (budesonide, celecoxib, aspirin, naproxen, licofelone), antidiabetic drugs (metformin, pioglitazone), antineoplastic agents (lapatinib, bexarotene, vorinostat), and other drugs and supplements (phenethyl isothiocyanate, myo-inositol, N-acetylcysteine, ascorbic acid, berry extracts). These drugs have been evaluated in mouse models mimicking interventions either in current smokers or in ex-smokers, or in prenatal chemoprevention. They display a broad spectrum of activities by attenuating either smoke-induced preneoplastic lesions or benign tumors and/or malignant tumors. Together with epidemiological data, these findings provide useful information to predict the potential effects of pharmacological agents in smokers.

Exploration of binding site pattern in arachidonic acid metabolizing enzymes, Cyclooxygenases and Lipoxygenases

Background

Cyclooxygenase (COXs) and Lipoxygenase (LOXs) pathways are the two major enzymatic pathways in arachidonic acid (AA) metabolism. The term eicosanoid is used to describe biologically active lipid mediators including prostaglandins, thromboxanes, leukotrienes and other oxygenated derivatives, which are produced primarily from AA. Eicosanoids generated in a tissue specific manner play a key role in inflammation and cancer. As AA is the substrate common to variety of COXs and LOXs, inhibition of one pathway results in diversion of the substrate to other pathways, which often is responsible for undesirable side effects. Hence there is need for development of not only isozyme specific inhibitors but also dual/multi enzyme inhibitors. Understanding the interactions of AA and characterizing its binding sites in these enzymes therefore is crucial for developing enzyme specific and multi enzyme inhibitors for enhancing therapeutic efficacy and/or overcoming side effects.

Results

AA binding sites in COXs and LOXs are identified and compared by the development of receptor based pharmacophore using MultiBind. Physico chemical properties were compared to understand the details of the binding sites in all the enzymes and to elucidate important amino acids that can be targeted for drug design. The alignment of AA binding sites in the seven enzymes COX-1, COX-2, 5-LOX, 12-LOX, 15-LOX and plant soybean LOX-1 and LOX-3 indicated a common pattern of five common interacting groups. In the same way, comparison of AA binding sites was done pair wise and by multiple alignment in various combinations. It has been identified that aliphatic and aromatic interactions are the most common in all the enzymes. In addition interactions unique to each one of these enzymes were identified.

Conclusion

The complete analysis of AA binding sites in the seven enzymes was performed; 120 combinations for the seven enzymes were studied in detail. All the seven enzymes are structurally quite different, yet they share AA as the common binding partner. Comparisons in various combinations showed how they are similar and dissimilar with each other. This information will be helpful in designing specific as well as common inhibitors.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1101-4) contains supplementary material, which is available to authorized users.

A comprehensive review in current developments of benzothiazole-based molecules in medicinal chemistry

Benzothiazole (BTA) and its derivatives are the most important heterocyclic compounds, which are common and integral feature of a variety of natural products and pharmaceutical agents. BTA shows a variety of pharmacological properties, and its analogs offer a high degree of structural diversity that has proven useful for the search of new therapeutic agents. The broad spectrum of pharmacological activity in individual BTA derivative indicates that, this series of compounds is of an undoubted interest. The related research and developments in BTA-based medicinal chemistry have become a rapidly developing and increasingly active topic. Particularly, numerous BTA-based compounds as clinical drugs have been extensively used in practice to treat various types of diseases with high therapeutic potency. This work systematically gives a comprehensive review in current developments of BTA-based compounds in the whole range of medicinal chemistry as anticancer, antibacterial, antifungal, antiinflammatory, analgesic, anti-HIV, antioxidant, anticonvulsant, antitubercular, antidiabetic, antileishmanial, antihistaminic, antimalarial and other medicinal agents. It is believed that, this review article is helpful for new thoughts in the quest for rational designs of more active and less toxic BTA-based drugs, as well as more effective diagnostic agents and pathologic probes.

Chemoprevention of urothelial cell carcinoma growth and invasion by the dual COX-LOX inhibitor licofelone in UPII-SV40T transgenic mice

Epidemiologic and clinical data suggest that use of anti-inflammatory agents is associated with reduced risk for bladder cancer. We determined the chemopreventive efficacy of licofelone, a dual COX-lipoxygenase (LOX) inhibitor, in a transgenic UPII-SV40T mouse model of urothelial transitional cell carcinoma (TCC). After genotyping, six-week-old UPII-SV40T mice (n = 30/group) were fed control (AIN-76A) or experimental diets containing 150 or 300 ppm licofelone for 34 weeks. At 40 weeks of age, all mice were euthanized, and urinary bladders were collected to determine urothelial tumor weights and to evaluate histopathology. Results showed that bladders of the transgenic mice fed control diet weighed 3 to 5-fold more than did those of the wild-type mice due to urothelial tumor growth. However, treatment of transgenic mice with licofelone led to a significant, dose-dependent inhibition of the urothelial tumor growth (by 68.6%-80.2%, P < 0.0001 in males; by 36.9%-55.3%, P < 0.0001 in females) compared with the control group. The licofelone diet led to the development of significantly fewer invasive tumors in these transgenic mice. Urothelial tumor progression to invasive TCC was inhibited in both male (up to 50%; P < 0.01) and female mice (41%-44%; P < 0.003). Urothelial tumors of the licofelone-fed mice showed an increase in apoptosis (p53, p21, Bax, and caspase3) with a decrease in proliferation, inflammation, and angiogenesis markers (proliferating cell nuclear antigen, COX-2, 5-LOX, prostaglandin E synthase 1, FLAP, and VEGF). These results suggest that licofelone can serve as potential chemopreventive for bladder TCC.

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.

Cytotoxic and apoptotic functions of licofelone on rat glioma cells

Gliomas are the largest group of central nervous system tumors and despite of clinical treatments death rate is very high. Inhibition of both cyclooxygenase and lipoxygenase pathways that take role in arachidonic acid metabolism prevents cancer development and induces apoptosis. One of the most promising compounds that blocks both of these pathways is licofelone. Using colchicine and 5-fluorouracil as positive controls, we questioned whether licofelone affects the survival of rat glioma cell line (C6) and induces apoptosis in vitro. After growing the cells in culture, we determined viability with MT, apoptosis with flow cytometry and activity of caspase enzymes with real time PCR. All used doses of colchicine and 5-fluorouracil were cytotoxic and reduced the number of surviving C6 cells as much as 44% and 60%, respectively. Comparing to the control, treatments with 10, 50 and 100 μM licofelone for 24 or 48 h did not influence C6 survival, however, 150, 200 and 250 μM licofelone reduced the number of living cells by 58, 88 and 93%, respectively, and induced apoptosis of C6 cells in a dose and time dependent manner. Licofelone did not change the level of caspase-9, but increased the level of caspase-3. Comparing with 5-fluorouracil and colchicine, the present study reveals for the first time the possibility that licofelone possesses a strong dose and time dependent antiproliferative and proapoptotic properties on glioma cells.

The Medicinal Timber Canarium patentinervium Miq. (Burseraceae Kunth.) Is an Anti-Inflammatory Bioresource of Dual Inhibitors of Cyclooxygenase (COX) and 5-Lipoxygenase (5-LOX)

The barks and leaves extracts of Canarium patentinervium Miq. (Burseraceae Kunth.) were investigated for cyclooxygenase (COX) and 5-lipoxygenase (LOX) inhibition via in vitro models. The corresponding antioxidative power of the plant extract was also tested via nonenzyme and enzyme in vitro assays. The ethanolic extract of leaves inhibited the enzymatic activity of 5-LOX, COX-1, and COX-2 with IC₅₀ equal to 49.66 ± 0.02 μg/mL, 0.60 ± 0.01 μg/mL, and 1.07 ± 0.01 μg/mL, respectively, with selective COX-2 activity noted in ethanolic extract of barks with COX-1/COX-2 ratio of 1.22. The ethanol extract of barks confronted oxidation in the ABTS, DPPH, and FRAP assay with EC₅₀ values equal to 0.93 ± 0.01 μg/mL, 2.33 ± 0.02 μg/mL, and 67.00 ± 0.32 μg/mL, respectively, while the ethanol extract of leaves confronted oxidation in β-carotene bleaching assay and superoxide dismutase (SOD) assay with EC₅₀ value of 6.04 ± 0.02 μg/mL and IC₅₀ value of 3.05 ± 0.01 μg/mL. The ethanol extract acts as a dual inhibitor of LOX and COX enzymes with potent antioxidant capacity. The clinical significance of these data is quite clear that they support a role for Canarium patentinervium Miq. (Burseraceae Kunth.) as a source of lead compounds in the management of inflammatory diseases.

Recent advances in the search for novel 5-lipoxygenase inhibitors

5-Lipoxygenase (5-LO) is an important enzyme of the arachidonic acid cascade and catalyses with the help of FLAP, the 5-LO-activating protein, the formation of bioactive leukotrienes (LTs). LTs are inflammatory mediators playing a pathophysiological role in different diseases such as asthma, allergic rhinitis as well as cardiovascular diseases and certain types of cancer. Up to now, only one 5-LO inhibitor is on the market, zileuton for the treatment of asthma. With the rising number of indications for anti-LT therapy, 5-LO inhibitor drug development becomes more and more important. This MiniReview gives an update on 5-LO inhibitors currently under clinical development. Furthermore, the recent advances in the search for novel 5-lipoxygenase inhibitors with a focus on computational methods are summarized. Currently, licofelone is the compound with the highest clinical development status (completed phase III trials). 5-LO inhibitor screening programmes based on computational methods could deliver several promising drug-like new molecules. These activities can be expected to be driven by the newly resolved structure of human 5-LO in the future, enabling structure-based drug design. For the prospective drugs in late-stage clinical development, the future will show their clinical safety and efficacy in the particular diseases.

Licofelone abolishes survival of carcinogenic fibroblasts by inducing apoptosis

Dual inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX) pathways of arachidonic acid metabolism prevent cancer development and induce apoptosis. One of the most promising compounds that blocks both of these pathways is licofelone. We questioned whether licofelone affects the survival and/or promotes apoptosis of H-ras transformed rat embryonic fibroblast (5RP7) cells in vitro. Using 5-fluorouracil (5-FU) and colchicine as positive controls, we determined cell viability with 3-3-(4,5-D-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, thyazolyl blue (MTT), apoptosis with flow cytometry and activity of caspase enzyme with real-time reverse transcription polymerase chain reaction (PCR). Compared to the control, all used six doses (10, 50, 100, 150, 250 and 250 µM) of 5-FU, colchicine and licofelone, which were cytotoxic and reduced the number of H-Ras transformed 5RP7 cells by as much as 78, 72 and 92%, respectively. In addition, we found that 150, 200 and 250 µM of licofelone induced apoptosis and necrosis of H-Ras transformed 5RP7 cells in a dose- and time-dependent manner. Each three tested drugs at 250 µM also increased the level of caspase-3 enzyme up to 5-fold. Although colchicine was effective in inducing early apoptosis, licofelone had much more capacity to induce the total of early plus late apoptosis by approximately 96% in cells after 48 hours. The present study reveals the possibility that licofelone posseses strong dose- and time-dependent anticancer and apoptotic properties on carcinogenic fibroblasts.

The dual cyclooxygenase/5-lipoxygenase inhibitor licofelone attenuates p-glycoprotein-mediated drug resistance in the injured spinal cord

There are currently no proven effective treatments that can improve recovery of function in spinal cord injury (SCI) patients. Many therapeutic compounds have shown promise in pre-clinical studies, but clinical trials have been largely unsuccessful. P-glycoprotein (Pgp, Abcb1b) is a drug efflux transporter of the blood-spinal cord barrier that limits spinal cord penetration of blood-borne xenobiotics. Pathological Pgp upregulation in diseases such as cancer causes heightened resistance to a broad variety of therapeutic drugs. Importantly, several drugs that have been evaluated for the treatment of SCI, such as riluzole, are known substrates of Pgp. We therefore examined whether Pgp-mediated pharmacoresistance diminishes delivery of riluzole to the injured spinal cord. Following moderate contusion injury at T10 in male Sprague-Dawley rats, we observed a progressive, spatial spread of increased Pgp expression from 3 days to 10 months post-SCI. Spinal cord uptake of i.p.-delivered riluzole was significantly reduced following SCI in wild type but not Abcb1a-knockout rats, highlighting a critical role for Pgp in mediating drug resistance following SCI. Because inflammation can drive Pgp upregulation, we evaluated the ability of the new generation dual anti-inflammatory drug licofelone to promote spinal cord delivery of riluzole following SCI. We found that licofelone both reduced Pgp expression and enhanced riluzole bioavailability within the lesion site at 72 h post-SCI. This work highlights Pgp-mediated drug resistance as an important obstacle to therapeutic drug delivery for SCI, and suggests licofelone as a novel combinatorial treatment strategy to enhance therapeutic drug delivery to the injured spinal cord.

Chemoprevention of 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster cheek pouch carcinogenesis by a 5-lipoxygenase inhibitor, garcinol

Our previous studies have shown that aberrant arachidonic acid metabolism, especially the 5-lipoxygenase (5-Lox) pathway, is involved in oral carcinogenesis and can be targeted for cancer prevention. To develop potent topical agents for oral cancer chemoprevention, 5 known 5-Lox inhibitors from dietary and synthetic sources (Zileuton, ABT-761, licofelone, curcumin, and garcinol) were evaluated in silico for their potential efficacy. Garcinol, a polyisoprenylated benzophenone from the fruit rind of Garcinia spp., was found to be a promising agent based on the calculation of a theoretical activity index. Computer modeling showed that garcinol well fit the active site of 5-Lox, and potentially inhibited enzyme activity through interactions between the phenolic hydroxyl groups and the non-heme catalytic iron. In a short-term study on 7,12-dimethylbenz[a]anthracene (DMBA)-treated hamster cheek pouch, topical garcinol suppressed leukotriene B4 (LTB4) biosynthesis and inhibited inflammation and cell proliferation in the oral epithelium. In a long-term carcinogenesis study, topical garcinol significantly reduced the size of visible tumors, the number of cancer lesions, cell proliferation, and LTB4 biosynthesis. These results demonstrated that topical application of a 5-Lox inhibitor, garcinol, had chemopreventive effect on DMBA-induced hamster cheek pouch carcinogenesis.

Efficient synthesis and 5-LOX/COX-inhibitory activity of some 3-hydroxybenzo[b]thiophene-2-carboxylic acid derivatives

A series of 3-hydroxybenzo[b]thiophene-2-carboxylic acid derivatives has been prepared and subsequently evaluated with regards to the inhibition of 5-LOX/COX. Structure optimization furnished derivatives with promising in vitro activity as dual 5-LOX/COX inhibitors with submicromolar IC(50) values for inhibition of 5-LOX and COX-1, respectively.

Licofelone inhibits interleukin-18-induced pro-inflammatory cytokine release and cellular proliferation in human mesangial cells

Licofelone, a novel dual anti-inflammatory drug that inhibits 5-lipoxygenase (5-LOX) and cyclooxygenase (COX), has recently been defined to have therapeutic effects in osteoarthritis. Both 5-LOX and COX play functional roles in the pathogenesis of glomerulonephritis in children as well. Interleukin-18 is a pro-inflammatory cytokine. It remains unclear whether licofelone can ameliorate inflammatory response of human mesangial cells (HMC) exposed to interleukin-18. In this study, HMC were cultured and exposed to interleukin-18 with or without pre-treatment of licofelone. COX-2 and 5-LOX enzyme activities in mesangial cells were determined with chromometry or high-performance liquid chromatography. Prostaglandin E2, cysteinyl leukotriene, monocyte chemotactic protein-1 and interferon-γ concentrations in culture medium were measured using an enzyme-linked immunosorbent assay. Western blotting was employed to detect phosphorylated mitogen-activated protein kinases ERK1/2, p38 and JNK1/2 in HMC. It was found that licofelone attenuated interleukin-18-induced COX-2 enzyme activity in HMC and prostaglandin E2 release in a dose-dependent manner. Similarly, licofelone inhibited interleukin-18-induced 5-LOX enzyme activity and leukotriene release. Licofelone reduced interleukin-18-induced phosphorylation of p38 mitogen-activated protein kinase and suppressed monocyte chemotactic protein-1 and interferon-γ synthesis. Moreover, licofelone inhibited IL-18-induced proliferation of mesangial cells. We conclude that licofelone inhibits interleukin-18-induced pro-inflammatory cytokine release and cellular proliferation in HMC, which may represent a really interesting therapeutic approach for glomerulonephritis in children.

Role of lipoxins, resolvins, and other bioactive lipids in colon and pancreatic cancer

Unresolved inflammation, due to insufficient production of proresolving anti-inflammatory lipid mediators, can lead to an increased risk of tumorigenesis and tumor cell invasiveness. Various bioactive lipids, particularly those formed by cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, have been well established as therapeutic targets for many epithelial cancers. Emerging studies suggest that there is a role for anti-inflammatory bioactive lipids and their mediators during the resolution phase of inflammation. These proresolving bioactive lipids, including lipoxins (LXs) and resolvins (RVs), have potent anti-inflammatory and anti-carcinogenic properties. The molecular signaling pathways controlling generation and degradation of the proresolving mediators LXs and RVs are now being elucidated, and the component molecules may serve as new targets for regulation of inflammation and inflammation-associated cancers like colon and pancreatic cancers. This review will highlight the recent advances in our understanding of how these bioactive lipids and proresolving mediators may function with various immune cells and cytokines in inhibiting tumor cell proliferation and progression and invasiveness of colon and pancreatic cancers.

Gastroprotective and safety effects of WIN-34B, a novel treatment for osteoarthritis, compared to NSAIDs

ETHNOPHARMACOLOGICAL RELEVANCE

The dried flowers of Lonicera japonica, also known as Japanese honeysuckle, and the dried root of Anemarrhena asphodeloides, the component herbs of WIN-34B, are traditionally used in Eastern medicine to treat various inflammatory conditions including arthritis.

OBJECTIVE

To study the acute and chronic toxicities of WIN-34B and to compare its effects on gastric mucosa with those of diclofenac, a widely used NSAID, and celecoxib, a selective COX-2 inhibitor.

MATERIALS AND METHODS

To investigate acute toxicity, we orally administered a single dose of 5,000 mg/kg WIN-34B to rats. To investigate chronic toxicity, we orally administered 500, 1000 or 2,000 mg/kg WIN-34B to rats daily for 13 weeks. To assess its effects on gastric mucosa, rats received either a single dose or repeated doses of WIN-34B (400, 1000, or 2,000 mg/kg), diclofenac (10, 40, or 80 mg/kg), celecoxib (100 or 1,000 mg/kg), or vehicle, after which samples of gastric mucosa were assessed grossly and histologically. We also measured tissue activity of myeloperoxidase and synthesis of eicosanoids, including prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)). To further assess its effects, we administered WIN-34B to rats either intraperitoneally or orally, measured gastric injury scores using a rat model of diclofenac-induced gastric injury, and measured eicosanoid synthesis.

RESULTS

WIN-34B showed no signs of acute or chronic toxicity in terms of general behavior, gross appearance of the internal organs, blood chemistry, or mortality. WIN-34B did not cause significant gastric mucosal damage after single or repeated doses. In contrast, diclofenac and celecoxib both caused gastric damage. In terms of eicosanoid synthesis, WIN-34B significantly suppressed LTB(4) synthesis while both diclofenac and celecoxib increased LTB(4) synthesis. WIN-34B slightly reduced PGE(2) production, while both diclofenac and celecoxib significantly reduced PGE(2) production. In a rat model of diclofenac-induced gastric injury, WIN-34B significantly suppressed LTB(4) synthesis and restored PGE(2) release.

CONCLUSIONS

These results demonstrate that WIN-34B did not cause acute or chronic toxicity in male or female rats. In addition, WIN-34B did not cause significant gastric mucosal damage, instead appearing to protect the mucosa from diclofenac-induced gastric damage through the regulation of PGE(2) and LTB(4).

Investigational pharmacology for low back pain

Study design:

Review and reinterpretation of existing literature.

Objective:

This review article summarizes the anatomy and pathogenesis of disease processes that contribute to low back pain, and discusses key issues in existing therapies for chronic low back pain. The article also explains the scientific rationale for investigational pharmacology and highlights emerging compounds in late development.

Results/conclusion:

While the diverse and complex nature of chronic low back pain continues to challenge clinicians, a growing understanding of chronic low back pain on a cellular level has refined our approach to managing chronic low back pain with pharmacology. Many emerging therapies with improved safety profiles are currently in the research pipeline and will contribute to a multimodal therapeutic algorithm in the near future. With the heterogeneity of the patient population suffering from chronic low back pain, the clinical challenge will be accurately stratifying the optimal pharmacologic approach for each patient.