Discovery of 4-(5-(cyclopropylcarbamoyl)-2-methylphenylamino)-5-methyl-N-propylpyrrolo[1,2-f][1,2,4]triazine-6-carboxamide (BMS-582949), a clinical p38α MAP kinase inhibitor for the treatment of inflammatory diseases

A p38 MAP kinase inhibitor suppresses osteoclastogenesis and alleviates ovariectomy-induced bone loss through the inhibition of bone turnover

Inhibition of excessive osteoclastic activity is an efficient therapeutic strategy for many bone diseases induced by increased bone resorption, such as osteoporosis. BMS-582949, a clinical p38α inhibitor, is a promising drug in Phase II studies for treating rheumatoid arthritis. However, its function on bone resorption is largely unknown. In this study, we find that BMS-582949 represses RANKL-induced osteoclast differentiation in a dose-dependent manner. Moreover, BMS-582949 inhibits osteoclastic F-actin ring formation and osteoclast-specific gene expression. Mechanically, BMS-582949 treatment attenuates RANKL-mediated osteoclastogenesis through mitogen-activated protein kinases (MAPKs) and protein kinase B (AKT) signaling pathways without disturbing nuclear factor-κB (NF-κB) signaling. Interestingly, BMS-582949 impairs osteoclastic mitochondrial biogenesis and functions, such as oxidative phosphorylation (OXPHOS). Furthermore, BMS-582949 administration prevents bone loss in ovariectomized mouse mode by inhibiting both bone resorption and bone formation in vivo. Taken together, these findings indicate that BMS-582949 may be a potential and effective drug for the therapy of osteolytic diseases.

Bacterial protease alleviate chronic liver fibrosis induced by thioacetamide through suppression of hepatic stellate cells consequently decrease its proliferative index

In chronic liver diseases, liver fibrosis occurs due to excessive extracellular matrix (ECM) protein accumulation. Approximately 2 million deaths occur yearly due to liver disease, while cirrhosis is the 11th most common cause of death. Therefore, newer compounds or biomolecules must be synthesized to treat chronic liver diseases. In this aspect, the present study focuses on the assessment of the anti-inflammatory and antioxidant impact of Bacterial Protease (BP) produced by a new mutant strain of bacteria (Bacillus cereus S6-3/UM90) and 4,4'-(2,5-dimethoxy-1,4-phenylene) bis (1-(3-ethoxy phenyl)-1H-1,2,3-triazole) (DPET) in the treatment of early stage of liver fibrosis induced by thioacetamide (TAA). Sixty male rats were divided into six groups, ten rats each as follows: (1) Control group, (2) BP group, (3) TAA group, (4) TAA-Silymarin (S) group, (5) TAA-BP group, and (6) TAA-DPET group. Liver fibrosis significantly elevated liver function ALT, AST, and ALP, as well as anti-inflammatory interleukin 6 (IL-6) and VEGF. The oxidative stress parameters (MDA, SOD, and NO) were significantly increased with a marked reduction in GSH. Expression of MAPK and MCP-1 was unregulated in the TAA group, with downregulation of Nrf₂ was observed. TAA caused histopathological alterations associated with hepatic vacuolation and fibrosis, increasing collagen fibers and high immuno-expression of VEGF. On the other hand, treatment with BP successfully improved the severe effects of TAA on the liver and restored histological architecture. Our study concluded the protective potentials of BP for attenuating liver fibrosis and could be used as adjuvant therapy for treating hepatic fibrosis.

Signaling pathways in rheumatoid arthritis: implications for targeted therapy

Rheumatoid arthritis (RA) is an incurable systemic autoimmune disease. Disease progression leads to joint deformity and associated loss of function, which significantly impacts the quality of life for sufferers and adds to losses in the labor force. In the past few decades, RA has attracted increased attention from researchers, the abnormal signaling pathways in RA are a very important research field in the diagnosis and treatment of RA, which provides important evidence for understanding this complex disease and developing novel RA-linked intervention targets. The current review intends to provide a comprehensive overview of RA, including a general introduction to the disease, historical events, epidemiology, risk factors, and pathological process, highlight the primary research progress of the disease and various signaling pathways and molecular mechanisms, including genetic factors, epigenetic factors, summarize the most recent developments in identifying novel signaling pathways in RA and new inhibitors for treating RA. therapeutic interventions including approved drugs, clinical drugs, pre-clinical drugs, and cutting-edge therapeutic technologies. These developments will hopefully drive progress in new strategically targeted therapies and hope to provide novel ideas for RA treatment options in the future.

ASK1 inhibitor NQDI‑1 decreases oxidative stress and neuroapoptosis via the ASK1/p38 and JNK signaling pathway in early brain injury after subarachnoid hemorrhage in rats

Oxidative stress and neuroapoptosis are key pathological processes after subarachnoid hemorrhage (SAH). The present study evaluated the anti‑oxidation and anti‑apoptotic neuroprotective effects of the apoptosis signal‑regulating kinase 1 (ASK1) inhibitor ethyl‑2,7‑dioxo‑2,7‑dihydro‑3H‑naphtho(1,2,3‑de)quinoline‑1‑carboxylate (NQDI‑1) in early brain injury (EBI) following SAH in a rat model. A total of 191 rats were used and the SAH model was induced using monofilament perforation. Western blotting was subsequently used to detect the endogenous expression levels of proteins. Immunofluorescence was then used to confirm the nerve cellular localization of ASK1. Short‑term neurological function was assessed using the modified Garcia scores and the beam balance test 24 h after SAH, whereas long‑term neurological function was assessed using the rotarod test and the Morris water maze test. Apoptosis of neurons was assessed by TUNEL staining and oxidative stress was assessed by dihydroethidium staining 24 h after SAH. The protein expression levels of phosphorylated (p‑)ASK1 and ASK1 rose following SAH. NQDI‑1 was intracerebroventricularly injected 1 h after SAH and demonstrated significant improvements in both short and long‑term neurological function and significantly reduced oxidative stress and neuronal apoptosis. Injection of NQDI‑1 caused a significant decrease in protein expression levels of p‑ASK1, p‑p38, p‑JNK, 4 hydroxynonenal, and Bax and significantly increased the protein expression levels of heme oxygenase 1 and Bcl‑2. The use of the p38 inhibitor BMS‑582949 or the JNK inhibitor SP600125 led to significant decreases in the protein expression levels of p‑p38 or p‑JNK, respectively, and a significant reduction in oxidative stress and neuronal apoptosis; however, these inhibitors did not demonstrate an effect on p‑ASK1 or ASK1 protein expression levels. In conclusion, treatment with NQDI‑1 improved neurological function and decreased oxidative stress and neuronal apoptosis in EBI following SAH in rats, possibly via inhibition of ASK1 phosphorylation and the ASK1/p38 and JNK signaling pathway. NQDI‑1 may be considered a potential agent for the treatment of patients with SAH.

Design, synthesis and anti-inflammatory activity of imidazol-5-yl pyridine derivatives as p38α/MAPK14 inhibitor

P38α/MAPK14 is intracellular signalling regulator involved in biosynthesis of inflammatory mediator cytokines (TNF-α, IL-1, IL-6, and IL-1b), which induce the production of inflammatory proteins (iNOS, NF-kB, and COX-2). In this study, drug repurposing strategies were followed to repositioning of a series of B-RAF ^V600E imidazol-5-yl pyridine inhibitors to inhibit P38α kinase. A group 25 reported P38α kinase inhibitors were used to build a pharmacophore model for mapping the target compounds and proving their affinity for binding in P38α active site. Target compounds were evaluated for their potency against P38α kinase, compounds 11a and 11d were the most potent inhibitors (IC₅₀ = 47 nM and 45 nM, respectively). In addition, compound 11d effectively inhibited the production of proinflammatory cytokinesTNF-α, 1L-6, and 1L-1β in LPS-induced RAW 264.7 macrophages with IC₅₀ values of 78.03 nM, 17.6 µM and 82.15 nM, respectively. The target compounds were tested for their anti-inflammatory activity by detecting the reduction of Nitric oxide (NO) and prostaglandin (PGE2) production in LPS-stimulated RAW 264.7 macrophages. Compound 11d exhibited satisfied inhibitory activity of the production of PGE2 and NO with IC₅₀ values of 0.29 µM and 0.61 µM, respectively. Molecular dynamics simulations of the most potent inhibitor 11d were carried out to illustrate its conformational stability in the binding site of P38α kinase.

Small-Molecule Kinase Inhibitors for the Treatment of Nononcologic Diseases

Great successes have been achieved in developing small-molecule kinase inhibitors as anticancer therapeutic agents. However, kinase deregulation plays essential roles not only in cancer but also in almost all major disease areas. Accumulating evidence has revealed that kinases are promising drug targets for different diseases, including cancer, autoimmune diseases, inflammatory diseases, cardiovascular diseases, central nervous system disorders, viral infections, and malaria. Indeed, the first small-molecule kinase inhibitor for treatment of a nononcologic disease was approved in 2011 by the U.S. FDA. To date, 10 such inhibitors have been approved, and more are in clinical trials for applications other than cancer. This Perspective discusses a number of kinases and their small-molecule inhibitors for the treatment of diseases in nononcologic therapeutic fields. The opportunities and challenges in developing such inhibitors are also highlighted.

Structure-Based Design, Synthesis, and Biological Evaluation of Imidazo[4,5-b]Pyridin-2-one-Based p38 MAP Kinase Inhibitors: Part 2

We identified novel potent inhibitors of p38 mitogen-activated protein (MAP) kinase using a structure-based design strategy, beginning with lead compound, 3-(butan-2-yl)-6-(2,4-difluoroanilino)-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one (1). To enhance the inhibitory activity of 1 against production of tumor necrosis factor-α (TNF-α) in human whole blood (hWB) cell assays, we designed and synthesized hybrid compounds in which the imidazo[4,5-b]pyridin-2-one core was successfully linked with the p-methylbenzamide fragment. Among the compounds evaluated, 3-(3-tert-butyl-2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-6-yl)-4-methyl-N-(1-methyl-1H-pyrazol-3-yl)benzamide (25) exhibited potent p38 inhibition, superior suppression of TNF-α production in hWB cells, and also significant in vivo efficacy in a rat model of collagen-induced arthritis (CIA). In this paper, we report the discovery of potent, selective, and orally bioavailable imidazo[4,5-b]pyridin-2-one-based p38 MAP kinase inhibitors.

Discovery of potent p38α MAPK inhibitors through a funnel like workflow combining in silico screening and in vitro validation

This work describes the rational discovery of novel chemotypes of p38α MAPK inhibitors using a funnel approach consisting of several computer-aided drug discovery methods and biological experiments. Among the identified hits, four compounds belonging to different chemical families showed IC₅₀ values lower than 10 μM. In particular, the 1,4-benzodioxane derivative 5 turned out to be a potent and efficient p38α MAPK inhibitor having IC₅₀ = 0.07 μM, and LE_exp and LipE values of 0.38 and 4.8, respectively; noteworthy, the compound had also a promising kinase selectivity profile and the capability to suppress p38α MAPK effects in human immune cells. Overall, the collected findings highlight that the applied strategy has been successful in generating chemical novelty in the inhibitor kinase field, providing suitable chemical candidates for further inhibitor optimization.

Structure-Based Design, Synthesis, and Biological Evaluation of Imidazo[4,5-b]pyridin-2-one-Based p38 MAP Kinase Inhibitors: Part 1

We identified a lead series of p38 mitogen-activated protein kinase inhibitors using a structure-based design strategy from high-throughput screening of hit compound 1. X-ray crystallography of 1 with the kinase showed an infrequent flip of the peptide bond between Met109 and Gly110, which was considered to lead to high kinase selectivity. Our structure-based design strategy was to conduct scaffold transformation of 1 with maintenance of hydrogen bond interactions with the flipped hinge backbone of the enzyme. In accordance with this strategy, we focused on scaffold transformation to identify imidazo[4,5-b]pyridin-2-one derivatives as potent inhibitors of the p38 MAP kinase. Of the compounds evaluated, 21 was found to be a potent inhibitor of the p38 MAP kinase, lipopolysaccharide-induced tumor necrosis factor-α (TNF-α) production in human monocytic leukemia cells, and TNF-α-induced production of interleukin-8 in human whole blood cells. Herein we describe the discovery of potent and orally bioavailable imidazo[4,5-b]pyridin-2-one-based p38 MAP kinase inhibitors that suppressed cytokine production in a human whole blood cell-based assay.

Anti-inflammatory activity of triazine derivatives: A systematic review

Triazines are heterocyclic compounds with a variety of biological activities that have been increasingly studied in recent years due to their versatile structure (three isoforms) and the different derivatives that can be synthesized from them to ensure functional motifs. This systematic review provides the evidence in the literature of the in vitro and in vivo anti-inflammatory activity of triazine derivatives from 2008 to June 2018. Four bibliographical databases were consulted (PubMed, Web of Science, EMBASE and Scopus), and a total of 48 studies were included in this paper based on our eligibility criteria. Although 35.17% of evaluated triazines were demonstrated to be promising anti-inflammatory agents, further studies need to be conducted to explore their pharmacological profiles in the medical research of drug discovery to control the risk factors and pathophysiology of several chronic inflammation-based diseases.

An Optimized Synthesis, Molecular Structure and Characterization of Benzylic Derivatives of 1,2,4-Triazin-3,5(2H,4H)-dione

4-Benzyl-1,2,4-triazin-3,5(2H,4H)-dione (3-benzyl-6-azauracil, 2), and 2,4-dibenzyl-1,2,4-triazin-3,5(2H,4H)-dione (1,3-dibenzyl-6-azauracil, 3) were synthesized by the reaction of 1,2,4-triazin-3,5(2H,4H)-dione (6-azauracil, 1) with benzyl bromide and potassium carbonate in dry acetone via the 18-crown-6-ether catalysis. In these reaction methods, we developed more convenient and efficient methodologies to afford compounds 2 and 3 in good yields. These compounds were characterized by ¹H- and ¹³C-NMR, MS spectrum, IR spectroscopy and elemental analysis. The structure of 2 was verified by 2D-NMR measurements, including gHSQC and gHMBC measurements. A single-crystal X-ray diffraction experiment indicated that compound 3, with the molecular formula C₁₇H₁₅N₃O₂, crystallized from a CH₃OH/CH₂Cl₂ diffusion solvent system in a monoclinic space group P2₁/c with a = 13.7844(13), b = 8.5691(8), c = 13.0527(12) Å, β = 105.961(2)°, V = 1482.3(2) ų, Z = 4, resulting in a density D_calc of 1.314 g/cm³. The crystal structure of compound 3 is tightly stabilized by contact with five other molecules from the six short contacts formed by intermolecular C-O···H-Car, C-H···Car, and weakly π···π stacking interactions. The dihedral angle 31.90° is formed by the mean planes of the benzene rings of the N-2 and N-4 benzyl groups.

Design, Synthesis, and Biological Evaluation of Novel Type I1/2 p38α MAP Kinase Inhibitors with Excellent Selectivity, High Potency, and Prolonged Target Residence Time by Interfering with the R-Spine

We recently reported 1a (skepinone-L) as a type I p38α MAP kinase inhibitor with high potency and excellent selectivity in vitro and in vivo. However, as a type I inhibitor, it is entirely ATP-competitive and shows just a moderate residence time. Thus, the scope was to develop a new class of advanced compounds maintaining the structural binding features of skepinone-L scaffold like inducing a glycine flip at the hinge region and occupying both hydrophobic regions I and II. Extending this scaffold with suitable residues resulted in an interference with the kinase's R-Spine. By synthesizing 69 compounds, we could significantly prolong the target residence time with one example to 3663 s, along with an excellent selectivity score of 0.006 and an outstanding potency of 1.0 nM. This new binding mode was validated by cocrystallization, showing all binding interactions typifying type I¹/₂ binding. Moreover, microsomal studies showed convenient metabolic stability of the most potent, herein reported representatives.

p38 Mitogen activated protein kinase (MAPK): a new therapeutic target for reducing the risk of adverse pregnancy outcomes

INTRODUCTION

Spontaneous preterm birth (PTB) and preterm premature rupture of the membranes (pPROM) remain as a major clinical and therapeutic problem for intervention and management. Current strategies, based on our knowledge of pathways of preterm labor, have only been effective, in part, due to major gaps in our existing knowledge of risks and risk specific pathways. Areas covered: Recent literature has identified physiologic aging of fetal tissues as a potential mechanistic feature of normal parturition. This process is affected by telomere dependent and p38 mitogen activated protein kinase (MAPK) induced senescence activation. Pregnancy associated risk factors can cause pathologic activation of this pathway that can cause oxidative stress induced p38 MAPK activation leading to senescence and premature aging of fetal tissues. Premature aging is associated with sterile inflammation capable of triggering preterm labor or preterm premature rupture of membranes. Preterm activation of p38MAPK can be considered as a key contributor to adverse pregnancies. Expert opinion: This review considers p38MAPK activation as a potential target for therapeutic interventions to prevent adverse pregnancy outcomes mediated by stress factors. In this review, we propose multiple strategies to prevent p38MAPK activation.

The "Cyclopropyl Fragment" is a Versatile Player that Frequently Appears in Preclinical/Clinical Drug Molecules

Recently, there has been an increasing use of the cyclopropyl ring in drug development to transition drug candidates from the preclinical to clinical stage. Important features of the cyclopropane ring are, the (1) coplanarity of the three carbon atoms, (2) relatively shorter (1.51 Å) C-C bonds, (3) enhanced π-character of C-C bonds, and (4) C-H bonds are shorter and stronger than those in alkanes. The present review will focus on the contributions that a cyclopropyl ring makes to the properties of drugs containing it. Consequently, the cyclopropyl ring addresses multiple roadblocks that can occur during drug discovery such as (a) enhancing potency, (b) reducing off-target effects,

Novel 5-Substituted 2-(Aylmethylthio)-4-chloro-N-(5-aryl-1,2,4-triazin-3-yl)benzenesulfonamides: Synthesis, Molecular Structure, Anticancer Activity, Apoptosis-Inducing Activity and Metabolic Stability

A series of novel 5-substituted 2-(arylmethylthio)-4-chloro-N-(5-aryl-1,2,4-triazin-3-yl) benzenesulfonamide derivatives 27-60 have been synthesized by the reaction of aminoguanidines with an appropriate phenylglyoxal hydrate in glacial acetic acid. A majority of the compounds showed cytotoxic activity toward the human cancer cell lines HCT-116, HeLa and MCF-7, with IC50 values below 100 μM. It was found that for the analogues 36-38 the naphthyl moiety contributed significantly to the anticancer activity. Cytometric analysis of translocation of phosphatidylserine as well as mitochondrial membrane potential and cell cycle revealed that the most active compounds 37 (HCT-116 and HeLa) and 46 (MCF-7) inhibited the proliferation of cells by increasing the number of apoptotic cells. Apoptotic-like, dose dependent changes in morphology of cell lines were also noticed after treatment with 37 and 46. Moreover, triazines 37 and 46 induced caspase activity in the HCT-116, HeLa and MCF-7 cell lines. Selected compounds were tested for metabolic stability in the presence of pooled human liver microsomes and NADPH, both R² and Ar = 4-CF₃-C₆H₄ moiety in 2-(R²-methylthio)-N-(5-aryl-1,2,4-triazin-3-yl)benzenesulfonamides simultaneously increased metabolic stability. The results pointed to 37 as a hit compound with a good cytotoxicity against HCT-116 (IC50 = 36 μM), HeLa (IC50 = 34 μM) cell lines, apoptosis-inducing activity and moderate metabolic stability.

Three stories on Eph kinase inhibitors: From in silico discovery to in vivo validation

Several selective and potent EphB4 inhibitors have been discovered, optimized and biophysically characterized by our groups over the past years. On the outset of these discoveries high throughput docking techniques were applied. Herein, we review the optimization campaigns started from three of these hits (Xan-A1, Pyr-A1 and Qui-A1) with emphasis on their in depth in vitro and in vivo characterization, together with previously unpublished angiogenesis and fluorescence based assays.

Old and new therapeutics for Rheumatoid Arthritis: in vivo models and drug development

Development of novel drugs for treatment of chronic inflammatory diseases is to a large extent dependent on the availability of good experimental in vivo models in order to perform preclinical tests of new drugs and for the identification of novel drug targets. Here, we review a number of existing rodent models for Rheumatoid Arthritis in the context of how these models have been utilized for developing established therapy in Rheumatoid Arthritis and, furthermore, the present use of animal models for studies of novel drug candidates. We have studied the literature in the field for the use of in vivo models during development of anti-rheumatic drugs; from Methotrexate to various antibody treatments, to novel drugs that are, or have recently been, in clinical trials. For novel drugs, we have explored websites for clinical trials. Although a single Rheumatoid Arthritis in vivo model cannot mirror the complexity of disease development, there exist a number of good animal models for Rheumatoid Arthritis, each defining some parts in disease development, which are useful for studies of drug response. We find that many of the established drugs were not tested in in vivo models before being used in the clinic, but rather animal models have been subsequently used to find mechanisms for efficacy. Finally, we report a number of novel drugs, tested in preclinical in vivo models, presently in clinical trials.

Targeting Mitogen-Activated Protein Kinase-Activated Protein Kinase 2 (MAPKAPK2, MK2): Medicinal Chemistry Efforts To Lead Small Molecule Inhibitors to Clinical Trials

The p38/MAPK-activated kinase 2 (MK2) pathway is involved in a series of pathological conditions (inflammation diseases and metastasis) and in the resistance mechanism to antitumor agents. None of the p38 inhibitors entered advanced clinical trials because of their unwanted systemic side effects. For this reason, MK2 was identified as an alternative target to block the pathway but avoiding the side effects of p38 inhibition. However, ATP-competitive MK2 inhibitors suffered from low solubility, poor cell permeability, and scarce kinase selectivity. Fortunately, non-ATP-competitive inhibitors of MK2 have been already discovered that allowed circumventing the selectivity issue. These compounds showed the additional advantage to be effective at lower concentrations in comparison to the ATP-competitive inhibitors. Therefore, although the significant difficulties encountered during the development of these inhibitors, MK2 is still considered as an attractive target to treat inflammation and related diseases to prevent tumor metastasis and to increase tumor sensitivity to chemotherapeutics.

Discovery of ((4-(5-(Cyclopropylcarbamoyl)-2-methylphenylamino)-5-methylpyrrolo[1,2-f][1,2,4]triazine-6-carbonyl)(propyl)carbamoyloxy)methyl-2-(4-(phosphonooxy)phenyl)acetate (BMS-751324), a Clinical Prodrug of p38α MAP Kinase Inhibitor

In search for prodrugs to address the issue of pH-dependent solubility and exposure associated with 1 (BMS-582949), a previously disclosed phase II clinical p38α MAP kinase inhibitor, a structurally novel clinical prodrug, 2 (BMS-751324), featuring a carbamoylmethylene linked promoiety containing hydroxyphenyl acetic acid (HPA) derived ester and phosphate functionalities, was identified. Prodrug 2 was not only stable but also water-soluble under both acidic and neutral conditions. It was effectively bioconverted into parent drug 1 in vivo by alkaline phosphatase and esterase in a stepwise manner, providing higher exposure of 1 compared to its direct administration, especially within higher dose ranges. In a rat LPS-induced TNFα pharmacodynamic model and a rat adjuvant arthritis model, 2 demonstrated similar efficacy to 1. Most importantly, it was shown in clinical studies that prodrug 2 was indeed effective in addressing the pH-dependent absorption issue associated with 1.

Protein-kinase inhibitors: A new treatment pathway for autoimmune and inflammatory diseases?

Although advances in biological medicine have seen significant progress in the treatment of autoimmune and inflammatory disease, many patients do not experience a satisfactory response. Hence, there are two challenges facing the medical research community. The first is to continue development in the field of existing biological therapies, such as monoclonal antibodies. The second is to open new frontiers of research and explore treatment alternatives for non-responders to other therapies. Attention has increasingly turned to the therapeutic potential of small molecule weight kinase inhibitors (SMKIs), currently used extensively in oncology and haematology. Initial research into the therapeutic value of SMKIs for autoimmune and inflammatory diseases has been encouraging. SMKIs are taken orally, which reduces cost for the health provider, and could increase compliance for the patient. This is why research is now focusing increasingly on SMKIs as a new generation line of treatment in these diseases. Tofacitinib, an inhibitor of Janus-kinase, is currently the only drug approved for the treatment of rheumatoid arthritis by FDA. However, much more needs to be done to understand the intracellular signalling pathways and how these might affect disease progression before solid conclusions can be drawn.

Conformational features of secondary N-cyclopropyl amides

NMR studies in conjunction with ab initio calculations revealed unexpected conformational behavior of N-cyclopropylacetamide (1). This secondary amide displays 16-19% E-rotamer (cis) around the carbonyl-nitrogen bond in apolar solvents, in contrast to other aliphatic secondary acetamides in which significant E-rotamer populations are rare due to steric contacts between the substituents on the amide bond. In addition, 1 adopts an ortho conformation around the N-cPr bond instead of the anti conformation generally preferred by secondary acetamides. This distinct conformational behavior was also observed for other secondary N-cyclopropyl amides.

The effect of BMS-582949, a P38 mitogen-activated protein kinase (P38 MAPK) inhibitor on arterial inflammation: a multicenter FDG-PET trial

OBJECTIVES

This study evaluated the effect of p38 mitogen-activated protein kinase (p38MAPK) inhibitor, BMS-582949, on atherosclerotic plaque inflammation, using (18)FDG-PET imaging. p38MAPK is an important element of inflammatory pathways in atherothrombosis and its inhibition may lead to reduced inflammation within atherosclerotic plaques.

METHODS

Subjects with documented atherosclerosis (n = 72) on stable low-dose statin therapy and having at least one lesion with active atherosclerotic plaque inflammation in either aorta or carotid arteries were randomized to BMS-582949 (100 mg once daily), placebo, or atorvastatin (80 mg once daily), for 12 weeks. Arterial inflammation was assessed using (18)FDG-PET/CT imaging of the carotid arteries and aorta. Uptake of arterial (18)FDG was assessed as target-to-background ratio (TBR): 1) as a mean of all slices of the index vessel, and 2) within active slices of all vessels (AS: which includes only slices with significant inflammation (TBR ≥ 1.6) at the baseline).

RESULTS

Treatment with BMS-582949 did not reduce arterial inflammation relative to placebo, (ΔTBR index: 0.10 [95% CI: -0.11, 0.30], p = 0.34; ΔTBR AS: -0.01 [-0.31, 0.28], p = 0.93) or hs-CRP (median %ΔCRP [IQR]: 33.83% [153.91] vs. 16.71% [133.45], p = 0.61). In contrast, relative to placebo, statin intensification was associated with significant reduction of hs-CRP (%ΔCRP [IQR]: -17.44% [54.68] vs. 16.71% [133.45], p = 0.04) and arterial inflammation in active slices (ΔTBRAS = -0.24 [95% CI: -0.46, -0.01], p = 0.04).

CONCLUSIONS

The findings of this study demonstrates that in stable atherosclerosis, 12 weeks of treatment with BMS-582949 did not reduce arterial inflammation or hs-CRP compared to placebo, whereas intensification of statin therapy significantly decreased arterial inflammation.

Synthesis of carbon-11-labeled 4-(phenylamino)-pyrrolo[2,1-f][1,2,4]triazine derivatives as new potential PET tracers for imaging of p38α mitogen-activated protein kinase

The reference standards methyl 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate (10a), methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate (10b) and corresponding precursors 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (11a), methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (11b) were synthesized from methyl crotonate and 3-amino-4-methylbenzoic acid in multiple steps with moderate to excellent yields. The target tracer [(11)C]methyl 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate ([(11)C]10a) and [(11)C]methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate ([(11)C]10b) were prepared from their corresponding precursors with [(11)C]CH3OTf under basic condition through O-[(11)C]methylation and isolated by a simplified solid-phase extraction (SPE) method in 50-60% radiochemical yields at end of bombardment (EOB) with 185-555 GBq/μmol specific activity at end of synthesis (EOS).

Functional roles of p38 mitogen-activated protein kinase in macrophage-mediated inflammatory responses

Inflammation is a natural host defensive process that is largely regulated by macrophages during the innate immune response. Mitogen-activated protein kinases (MAPKs) are proline-directed serine and threonine protein kinases that regulate many physiological and pathophysiological cell responses. p38 MAPKs are key MAPKs involved in the production of inflammatory mediators, including tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2). p38 MAPK signaling plays an essential role in regulating cellular processes, especially inflammation. In this paper, we summarize the characteristics of p38 signaling in macrophage-mediated inflammation. In addition, we discuss the potential of using inhibitors targeting p38 expression in macrophages to treat inflammatory diseases.

Ligand placement based on prior structures: the guided ligand-replacement method

The process of iterative structure-based drug design involves the X-ray crystal structure determination of upwards of 100 ligands with the same general scaffold (i.e. chemotype) complexed with very similar, if not identical, protein targets. In conjunction with insights from computational models and assays, this collection of crystal structures is analyzed to improve potency, to achieve better selectivity and to reduce liabilities such as absorption, distribution, metabolism, excretion and toxicology. Current methods for modeling ligands into electron-density maps typically do not utilize information on how similar ligands bound in related structures. Even if the electron density is of sufficient quality and resolution to allow de novo placement, the process can take considerable time as the size, complexity and torsional degrees of freedom of the ligands increase. A new module, Guided Ligand Replacement (GLR), was developed in Phenix to increase the ease and success rate of ligand placement when prior protein-ligand complexes are available. At the heart of GLR is an algorithm based on graph theory that associates atoms in the target ligand with analogous atoms in the reference ligand. Based on this correspondence, a set of coordinates is generated for the target ligand. GLR is especially useful in two situations: (i) modeling a series of large, flexible, complicated or macrocyclic ligands in successive structures and (ii) modeling ligands as part of a refinement pipeline that can automatically select a reference structure. Even in those cases for which no reference structure is available, if there are multiple copies of the bound ligand per asymmetric unit GLR offers an efficient way to complete the model after the first ligand has been placed. In all of these applications, GLR leverages prior knowledge from earlier structures to facilitate ligand placement in the current structure.

Synthesis and evaluation of carbamoylmethylene linked prodrugs of BMS-582949, a clinical p38α inhibitor

A series of carbamoylmethylene linked prodrugs of 1 (BMS-582949), a clinical p38α inhibitor, were synthesized and evaluated. Though the phosphoryloxymethylene carbamates (3, 4, and 5) and α-aminoacyloxymethylene carbamates (22, 23, and 26) were found unstable at neutral pH values, fumaric acid derived acyloxymethylene carbamates (2, 28, and 31) were highly stable under both acidic and neutral conditions. Prodrugs 2 and 31 were also highly soluble at both acidic and neutral pH values. At a solution dose of 14.2mpk (equivalent to 10mpk of 1), 2 gave essentially the same exposure of 1 compared to dosing 10mpk of 1 itself. At a suspension dose of 142mpk (equivalent to 100mpk of 1), 2 demonstrated that it could overcome the solubility issue associated with 1 and provide a much higher exposure of 1. To our knowledge, the unique type of prodrugs like 2, 28, and 31 was not reported in the past and could represent a novel prodrug approach for secondary amides, a class of molecules frequently identified as drug candidates.

Identification, synthesis, and biological evaluation of 6-[(6R)-2-(4-fluorophenyl)-6-(hydroxymethyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidin-3-yl]-2-(2-methylphenyl)pyridazin-3(2H)-one (AS1940477), a potent p38 MAP kinase inhibitor

Several p38 MAPK inhibitors have been shown to effectively block the production of cytokines such as IL-1β, TNFα, and IL-6. Inhibitors of p38 MAP kinase therefore have significant therapeutic potential for the treatment of autoimmune disease. Compound 2a was identified as a potent TNFα production inhibitor in vitro but suffered from poor oral bioavailability. Structural modification of 2a led to the discovery of tetrahydropyrazolopyrimidine derivatives, exemplified by compound 3, with an improved pharmacokinetic profile. We found that blocking metabolism at the methyl group of the amine and constructing the tetrahydropyrimidine core were important to obtaining compounds with good biological profiles and oral bioavailability. Pursuing the structure-activity relationships of this series led to the discovery of AS1940477 (3f), with excellent cellular activity and a favorable pharmacokinetic profile. This compound represents a highly potent inhibitor of p38 MAP kinase with regard to in vivo activity in an adjuvant-induced arthritis model.

Novel systemic drugs under investigation for the treatment of psoriasis

In the last few years, there has been progress in identifying some of the risk genes for psoriasis. This has resulted in a major impetus toward drug development as many of the same pathways and processes identified in psoriasis have been shown to have major roles in other chronic inflammatory diseases, suggesting that psoriasis can be used as a treatment model for many other diseases. This has resulted in a shift in research toward a select number of biological processes and has been accompanied by a surge in drug development with over 20 systemic agents currently in clinical testing for psoriasis, many of which target the pathways identified through genetic and basic research. Although it is too early to tell for many of these agents how effective and safe they will be, and where they will fit into treatment algorithms, it is evident that our range of options in treating this often perplexing disease will greatly increase in the future.

Discovery of pyrrolo[2,1-f][1,2,4]triazine C6-ketones as potent, orally active p38α MAP kinase inhibitors

Pyrrolo[2,1-f][1,2,4]triazine based inhibitors of p38α have been prepared exploring functional group modifications at the C6 position. Incorporation of aryl and heteroaryl ketones at this position led to potent inhibitors with efficacy in in vivo models of acute and chronic inflammation.