Kinase inhibitors: a new class of antirheumatic drugs

Distinct binding modes of a benzothiazole derivative confer structural bases for increasing ERK2 or p38α MAPK selectivity

Mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase 2 (ERK2) and p38α MAP kinase (p38α MAPK), regulate various cellular responses. ERK2 is a drug target for treating many diseases, such as cancer, whereas p38α has attracted much attention as a promising drug target for treating inflammatory disorders. ERK2 is a critical off-target for p38α MAPK and vice versa. In this study, an allosteric ERK2 inhibitor with a benzothiazole moiety (compound 1) displayed comparable inhibitory activity against p38α MAPK. Crystal structures of these MAPKs showed that compound 1 bound to the allosteric site of ERK2 and p38α MAPK in distinct manners. Compound 1 formed a covalent bond with Cys162 of p38α MAPK, whereas this covalent bond was absent in the ERK2 complex even though the corresponding cysteine is conserved in ERK2. Structural dissection combined with computational simulations indicated that an amino acid difference in the allosteric site is responsible for the distinct binding modes of compound 1 with ERK2 and p38α MAPK. These structural insights underline the feasibility of developing highly selective and potent ERK2 and p38α MAPK inhibitors.

Recent Advances in Dual BRD4-Kinase Inhibitors Base on Polypharmacology

Epigenetic reader BRD4 is involved in chromatin remodeling and transcriptional regulation, making it a promising therapeutic target. However, during the past decades, the results of many BRD4 inhibitors that have entered clinical trials were, in the main, unsatisfactory, due to some therapeutic limitations such as off-target effects and drug resistance. Combining a BRD4 inhibitor with another drug was expected to be an ideal option to overcome these "bottlenecks" and achieve improved therapeutic outcomes. However, combination therapy might trigger toxicity caused by drug-drug interaction, complex pharmacokinetic and additive effects. Recently, the application of dual-target drugs targeting BRD4 and other kinases has emerged to be an attractive approach to remedy defects of a single BRD4 inhibitor. Herein, this review focuses on recent advances in the discovery of dual BRD4-kinase inhibitors, with emphasis on their co-crystal structures and structure-activity relationships (SARs), as well as perspective prospects in the field.

Identification of an allosteric and Smad3-selective inhibitor of p38αMAPK using a substrate-based approach

p38α mitogen activated protein kinase (MAPK) plays important roles in multiple cellular functions by phosphorylating a wide variety of substrates, and therefore, p38α MAPK has been considered as an important drug target. In this study, we designed peptide-based inhibitors for p38α MAPK, which can only inhibit the Smad3 phosphorylation specifically, by targeting the KIM binding site of p38α MAPK. Peptide 6 showed a significant inhibitory potency for the Smad3 phosphorylation by p38α MAPK. Peptide 6 showed no ATP dependency, and did not inhibit the phosphorylation of other substrates by p38α MAPK. The discovery of peptide 6 by targeting the KIM binding site likely provide an opportunity for the discovery of a novel class of allosteric and substrate-specific p38α MAPK inhibitors.

Biologic and advanced immunomodulating therapeutic options for sarcoidosis: a clinical update

Introduction: Sarcoidosis is a multi-organ disease with a wide range of clinical manifestations and outcomes. A quarter of sarcoidosis patients require long-term treatment for chronic disease. In this group, corticosteroids and cytotoxic agents be insufficient to control diseaseAreas covered: Several biologic agents have been studied for treatment of chronic pulmonary and extra-pulmonary disease. A review of the available literature was performed searching PubMed and an expert opinion regarding specific therapy was developed.Expert opinion: These agents have the potential of treating patients who have progressive disease. Many of these agents have different mechanisms of action, response rates, and toxicity profiles.

Recent advance of spleen tyrosine kinase in diseases and drugs

Spleen tyrosine kinase (Syk) is a non-receptor protein tyrosine kinase, also known as p72Syk. It is important for downstream signaling from cell surface receptors, such as Fc receptors, complement receptors and integrin. Syk plays the critical role in triggering immune and allergic reactions, the signaling pathway of Syk has become the research focus on drugs for allergic disease and human malignancies. This review summarized the characteristics of Syk, its mechanism in related reactions, and mainly discussed the signal transduction pathway mediated by Syk. With the development of industry and the aggravation of environmental pollution, the incidence of allergic diseases is increasing, it has become a global priority disease. In this process, Syk participates in IgE/FcεRI signaling pathway plays a critical role in triggering allergic reactions. This review described the characteristics and the interaction mechanism of Syk and its binding proteins in disease, and summarized the research status of targeted Syk inhibitors.

Evaluation of the therapeutic potential of the selective p38 MAPK inhibitor Skepinone-L and the dual p38/JNK 3 inhibitor LN 950 in experimental K/BxN serum transfer arthritis

BACKGROUND

Mitogen-activated protein kinase (MAPK) signaling plays an important role in inflammatory diseases such as rheumatoid arthritis (RA).The aim of our study was to elucidate the therapeutic potential of the highly selective p38 MAPK inhibitor Skepinone-L and the dual inhibitor LN 950 (p38 MAPK and JNK 3) in the K/BxN serum transfer model of RA. Additionally, we aimed to monitor MAPK treatment non-invasively in vivo using the hypoxia tracer [¹⁸F]fluoromisonidazole ([¹⁸F]FMISO) and positron emission tomography (PET).

METHODS

To induce experimental arthritis, we injected glucose-6-phosphate isomerase autoantibody-containing serum in BALB/c mice. MAPK inhibitor or Sham treatment was administered per os once daily. On days 3 and 6 after arthritis induction, we conducted PET imaging with [¹⁸F]FMISO. At the end of the experiment, ankles were harvested for histopathological analysis.

RESULTS

Skepinone-L and LN 950 were applicable to suppress the severity of experimental arthritis confirmed by reduced ankle swelling and histopathological analysis. Skepinone-L (3.18 ± 0.19 mm) and LN 950 (3.40 ± 0.13 mm) treatment yielded a significantly reduced ankle thickness compared to Sham-treated mice (3.62 ± 0.11 mm) on day 5 after autoantibody transfer, a time-point characterized by severe arthritis. Hypoxia imaging with [¹⁸F]FMISO revealed non-conclusive results and might not be an appropriate tool to monitor MAPK therapy in experimental RA.

CONCLUSION

Both the selective p38 MAPK inhibitor Skepinone-L and the dual (p38 MAPK and JNK 3) inhibitor LN 950 exhibited significant therapeutic effects during experimental arthritis. Thus, our study contributes to the ongoing discussion on the use of p38 MAPK as a potential target in RA.

Selective inhibition of the p38α MAPK-MK2 axis inhibits inflammatory cues including inflammasome priming signals

A unique p38α MAPK–MK2 pathway inhibitor, CDD-450, is used to uncover the function of this protein complex in inflammasome priming signals. Importantly, CDD-450 is as efficacious as global p38α MAPK inhibitors in decreasing inflammation in disease models.

p38α activation of multiple effectors may underlie the failure of global p38α inhibitors in clinical trials. A unique inhibitor (CDD-450) was developed that selectively blocked p38α activation of the proinflammatory kinase MK2 while sparing p38α activation of PRAK and ATF2. Next, the hypothesis that the p38α–MK2 complex mediates inflammasome priming cues was tested. CDD-450 had no effect on NLRP3 expression, but it decreased IL-1β expression by promoting IL-1β mRNA degradation. Thus, IL-1β is regulated not only transcriptionally by NF-κB and posttranslationally by the inflammasomes but also posttranscriptionally by p38α–MK2. CDD-450 also accelerated TNF-α and IL-6 mRNA decay, inhibited inflammation in mice with cryopyrinopathy, and was as efficacious as global p38α inhibitors in attenuating arthritis in rats and cytokine expression by cells from patients with cryopyrinopathy and rheumatoid arthritis. These findings have clinical translation implications as CDD-450 offers the potential to avoid tachyphylaxis associated with global p38α inhibitors that may result from their inhibition of non-MK2 substrates involved in antiinflammatory and housekeeping responses.

JTE-852, a novel spleen tyrosine kinase inhibitor, blocks immunoglobulin G-mediated cellular responses and autoimmune reactions in vivo

AIMS

Immune and inflammatory responses mediated by immunoglobulin (Ig) G are largely responsible for the pathogenesis of autoimmune diseases. Spleen tyrosine kinase (Syk) plays a pivotal role in the IgG-mediated responses; therefore, Syk has emerged as a new therapeutic target for the treatment of autoimmune diseases. In this study, we investigated the inhibitory actions of JTE-852, a novel Syk inhibitor, on IgG-mediated cellular responses and autoimmune reactions in vivo.

MAIN METHODS

We examined mediator secretion from human monocytes. We also conducted rat models of reversed cutaneous anaphylaxis (RCA) and reversed passive Arthus (RPA), which are classified as type II and type III hypersensitivities, respectively. In a rat collagen-induced arthritis (CIA) model, JTE-852 or methotrexate was administered preventively (before the onset of arthritis) or therapeutically (after the onset of arthritis).

KEY FINDINGS

JTE-852 blocked secretion of reactive oxygen species and tumor necrosis factor-α from monocytes stimulated by IgG crosslinking. In the RCA and RPA models, JTE-852 also suppressed edema and dye leakage, respectively. In the CIA model, JTE-852 showed both preventive and therapeutic effects against joint swelling and bone erosion; on the other hand, methotrexate did not show the therapeutic effect.

SIGNIFICANCE

JTE-852 attenuates IgG-mediated responses and signs in animal model of autoimmune diseases. JTE-852 is thus a promising candidate for a novel, orally available drug for the treatment of autoimmune diseases.

Efficacy, Safety, Pharmacokinetics, and Pharmacodynamics of Filgotinib, a Selective JAK-1 Inhibitor, After Short-Term Treatment of Rheumatoid Arthritis: Results of Two Randomized Phase IIa Trials

OBJECTIVE

JAK inhibitors have shown efficacy in rheumatoid arthritis (RA). We undertook this study to test our hypothesis that selective inhibition of JAK-1 would combine good efficacy with a better safety profile compared with less selective JAK inhibitors.

METHODS

In two 4-week exploratory, double-blind, placebo-controlled phase IIa trials, 127 RA patients with an insufficient response to methotrexate (MTX) received filgotinib (GLPG0634, GS-6034) oral capsules (100 mg twice daily or 30, 75, 150, 200, or 300 mg once daily) or placebo, added onto a stable regimen of MTX, to evaluate safety, efficacy, pharmacokinetics (PK), and pharmacodynamics (PD) of filgotinib. The primary efficacy end point was the number and percentage of patients in each treatment group meeting the American College of Rheumatology 20% improvement criteria (achieving an ACR20 response) at week 4.

RESULTS

Treatment with filgotinib at 75-300 mg met the primary end point and showed early onset of efficacy. ACR20 response rates progressively increased to week 4, and the Disease Activity Score in 28 joints using the C-reactive protein (CRP) level decreased. Marked and sustained improvements were observed in serum CRP level and other PD markers. The PK of filgotinib and its major metabolite was dose proportional over the 30-300 mg range. Early side effects seen with other less selective JAK inhibitors were not observed (e.g., there was no worsening of anemia [JAK-2 inhibition related], no effects on liver transaminases, and no increase in low-density lipoprotein or total cholesterol). A limited decrease in neutrophils without neutropenia was consistent with immunomodulatory effects through JAK-1 inhibition. There were no infections. Overall, filgotinib was well tolerated. Events related to study drug were mild or moderate and transient during therapy, and the most common such event was nausea.

CONCLUSION

Selective inhibition of JAK-1 with filgotinib shows initial efficacy in RA with an encouraging safety profile in these exploratory studies.

Oxindole-based SYK and JAK3 dual inhibitors for rheumatoid arthritis: designing, synthesis and biological evaluation

Aim: Autoimmune disorders have complex pathophysiology and focus is laid on the development of multitargeted agents. Two well-established kinases: SYK and JAK3, were considered to design dual inhibitors as potential therapeutics using various molecular-modeling approaches. Mehodology: Pharmacophore models for SYK and JAK3 were generated using oxindole-based inhibitors. Furthermore, an in-house database was designed that was screened against the best selected models. The obtained hits were employed for docking analysis and subjected to MM-GBSA analysis and molecular dynamic simulation. Results: Top five oxindole derivatives were synthesized and evaluated for in vitro SYK and JAK3 activity. The most active compound 4a was evaluated for in vivo antiarthritic activity. It showed significant anti-arthritic activity. Conclusion: Thus, the designed inhibitors resulted in potential therapeutic agents for rheumatoid arthritis.

Molecular modeling study of CP-690550 derivatives as JAK3 kinase inhibitors through combined 3D-QSAR, molecular docking, and dynamics simulation techniques

To develop more potent JAK3 kinase inhibitors, a series of CP-690550 derivatives were investigated using combined molecular modeling techniques, such as 3D-QSAR, molecular docking and molecular dynamics (MD). The leave-one-out correlation (q²) and non-cross-validated correlation coefficient (r²) of the best CoMFA model are 0.715 and 0.992, respectively. The q² and r² values of the best CoMSIA model are 0.739 and 0.995, respectively. The steric, electrostatic, and hydrophobic fields played important roles in determining the inhibitory activity of CP-690550 derivatives. Some new JAK3 kinase inhibitors were designed. Some of them have better inhibitory activity than the most potent Tofacitinib (CP-690550). Molecular docking was used to identify some key amino acid residues at the active site of JAK3 protein. 10ns MD simulations were successfully performed to confirm the detailed binding mode and validate the rationality of docking results. The calculation of the binding free energies by MMPBSA method gives a good correlation with the predicted biological activity. To our knowledge, this is the first report on MD simulations and free energy calculations for this series of compounds. The combination results of this study will be valuable for the development of potent and novel JAK3 kinase inhibitors.

IL33 in rheumatoid arthritis: potential contribution to pathogenesis

A better understanding of the inflammatory mechanisms of rheumatoid arthritis and the development of biological therapy revolutionized its treatment, enabling an interference in the synovitis - structural damage - functional disability cycle. Interleukin 33 was recently described as a new member of the interleukin-1 family, whose common feature is its pro-inflammatory activity. Its involvement in the pathogenesis of a variety of diseases, including autoimmune diseases, raises the interest in the possible relationship with rheumatoid arthritis. Its action has been evaluated in experimental models of arthritis as well as in serum, synovial fluid and membrane of patients with rheumatoid arthritis. It has been shown that the administration of interleukin-33 exacerbates collagen-induced arthritis in experimental models, and a positive correlation between cytokine concentrations in serum and synovial fluid of patients with rheumatoid arthritis and disease activity was found. This review discusses evidence for the role of interleukin-33 with a focus on rheumatoid arthritis.

VX-509 (Decernotinib), an Oral Selective JAK-3 Inhibitor, in Combination With Methotrexate in Patients With Rheumatoid Arthritis

OBJECTIVE

To assess the efficacy and safety of decernotinib (VX-509), an oral selective inhibitor of JAK-3, in patients with rheumatoid arthritis (RA) in whom the response to methotrexate treatment was inadequate.

METHODS

In this 24-week, double-blind, randomized phase IIb study, 358 patients with active RA received either placebo (n = 71) or VX-509 at dosages of 100 mg/day (n = 71), 150 mg/day (n = 72), 200 mg/day (n = 72), or 100 mg twice daily (n = 72). Primary measures of efficacy at week 12 were the response rate according to the American College of Rheumatology 20% improvement criteria (ACR20) and change from baseline in the Disease Activity Score in 28 joints using the C-reactive protein level (DAS28-CRP).

RESULTS

At week 12, the ACR20 response rates were 46.5%, 66.7%, 56.9%, and 68.1% in the groups receiving VX-509 at dosages of 100 mg/day, 150 mg/day, 200 mg/day, and 100 mg twice daily, respectively, and 18.3% in the placebo group (P < 0.001 for all comparisons). At week 12, the mean change from baseline in the DAS28-CRP was significantly greater in each VX-509 group compared with the placebo group (P < 0.001). Improvements were maintained at week 24, as shown by the ACR20, ACR50, and ACR70 response rates and mean change from baseline in the DAS28-CRP. The most common adverse event in the VX-509 group was headache (8.7%), and elevated levels of transaminases, lipoproteins, and creatinine were observed.

CONCLUSION

VX-509 significantly improved the signs and symptoms of RA at weeks 12 and 24 compared with the placebo group when it was administered in combination with methotrexate. Safety signals included infection and increases in liver transaminase and lipid levels.

Innovative computer-aided methods for the discovery of new kinase ligands

Recent evidence points to significant roles played by protein kinases in cell signaling and cellular proliferation. Faulty protein kinases are involved in cancer, diabetes and chronic inflammation. Efforts are continuously carried out to discover new inhibitors for selected protein kinases. In this review, we discuss two new computer-aided methodologies we developed to mine virtual databases for new bioactive compounds. One method is ligand-based exploration of the pharmacophoric space of inhibitors of any particular biotarget followed by quantitative structure–activity relationship-based selection of the best pharmacophore(s). The second approach is structure-based assuming that potent ligands come into contact with binding site spots distinct from those contacted by weakly potent ligands. Both approaches yield pharmacophores useful as 3D search queries for the discovery of new bioactive (kinase) inhibitors.

Stem cell death and survival in heart regeneration and repair

Cardiovascular diseases are major causes of mortality and morbidity. Cardiomyocyte apoptosis disrupts cardiac function and leads to cardiac decompensation and terminal heart failure. Delineating the regulatory signaling pathways that orchestrate cell survival in the heart has significant therapeutic implications. Cardiac tissue has limited capacity to regenerate and repair. Stem cell therapy is a successful approach for repairing and regenerating ischemic cardiac tissue; however, transplanted cells display very high death percentage, a problem that affects success of tissue regeneration. Stem cells display multipotency or pluripotency and undergo self-renewal, however these events are negatively influenced by upregulation of cell death machinery that induces the significant decrease in survival and differentiation signals upon cardiovascular injury. While efforts to identify cell types and molecular pathways that promote cardiac tissue regeneration have been productive, studies that focus on blocking the extensive cell death after transplantation are limited. The control of cell death includes multiple networks rather than one crucial pathway, which underlies the challenge of identifying the interaction between various cellular and biochemical components. This review is aimed at exploiting the molecular mechanisms by which stem cells resist death signals to develop into mature and healthy cardiac cells. Specifically, we focus on a number of factors that control death and survival of stem cells upon transplantation and ultimately affect cardiac regeneration. We also discuss potential survival enhancing strategies and how they could be meaningful in the design of targeted therapies that improve cardiac function.

Profile of tofacitinib citrate and its potential in the treatment of moderate-to-severe chronic plaque psoriasis

The outlook for patients with psoriasis has improved significantly over the last 10 years with the introduction of targeted therapies. Cytokines exert their effects by activating intracellular signaling and transcription pathways, among which there are Janus kinases (JAKs) and signal transducers and activators of transcription (STAT) pathways. JAKs are intracellular second messengers that are crucial for transmitting extracellular cytokine signals to the cell. JAK inhibition interrupts intracellular signaling and can suppress immune cell activation and inflammation in T-cell-mediated disorders, such as psoriasis. Consequently, JAKs are the subject of intensive research activity, since they represent possible therapeutic targets. Tofacitinib is an orally available compound belonging to a novel category of nonbiologic drugs, the "JAK inhibitors", which target JAKs. Recently, oral and topical formulations of tofacitinib have been demonstrated to be safe and effective for the treatment of plaque psoriasis in randomized clinical trials. In particular, a 10 mg bid dose of tofacitinib was shown to be noninferior to etanercept 50 mg subcutaneously twice weekly. Questions remain unresolved regarding the safety risk beyond the 5 mg bid dose. This review, assessing the available scientific literature, focuses on the profile of tofacitinib, as investigational compound in the treatment of plaque psoriasis. An overview of the efficacy and safety data from randomized clinical trials is provided. In addition, the authors highlight future potential applications of tofacitinib in other skin diseases, in particular alopecia areata and vitiligo.

Role of mitogen- and stress-activated kinases in inflammatory arthritis

Lysophosphatidic acid (LPA) is a pleiotropic lipid mediator that promotes motility, survival, and the synthesis of chemokines/cytokines in human fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis. LPA activates several proteins within the mitogen activated protein (MAP) kinase signaling network, including extracellular signal-regulated kinases (ERK) 1/2 and p38 MAP kinase (MAPK). Upon docking to mitogen- and stress-activated kinases (MSKs), ERK1/2 and p38 MAPK phosphorylate serine and threonine residues within its C-terminal domain and cause autophosphorylation of MSKs. Activated MSKs can then directly phosphorylate cAMP response element-binding protein (CREB) at Ser133 in FLS. Phosphorylation of CREB by MSKs is essential for the production of pro-inflammatory and anti-inflammatory cytokines. However, other downstream effectors of MSK1/2 such as nuclear factor-kappa B, histone H3, and high mobility group nucleosome binding domain 1 may also regulate gene expression in immune cells involved in disease pathogenesis. MSKs are master regulators of cell function that integrate signals induced by growth factors, pro-inflammatory cytokines, and cellular stresses, as well as those induced by LPA.

Going with the flow: harnessing the power of the vasculature for targeted therapy in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, autoimmune disease that leads to excessive joint inflammation and is associated with significant morbidity and mortality. Although much is still to be learned about the aetiology RA, a growing body of evidence suggests that an altered vascular environment is an important aspect of its pathophysiology. In this context, RA shares many similarities with cancer, and it is expected that several angiogenic targets in cancer might be relevant to the treatment of RA. Here, we discuss how these targets can be combined with advances in drug development to generate the next generation of RA therapeutics.

Phosphorylation of αB-crystallin: Role in stress, aging and patho-physiological conditions

BACKGROUND

αB-crystallin, once thought to be a lenticular protein, is ubiquitous and has critical roles in several cellular processes that are modulated by phosphorylation. Serine residues 19, 45 and 59 of αB-crystallin undergo phosphorylation. Phosphorylation of S45 is mediated by p44/42 MAP kinase, whereas S59 phosphorylation is mediated by MAPKAP kinase-2. Pathway involved in S19 phosphorylation is not known.

SCOPE OF REVIEW

The review highlights the role of phosphorylation in (i) oligomeric structure, stability and chaperone activity, (ii) cellular processes such as apoptosis, myogenic differentiation, cell cycle regulation and angiogenesis, and (iii) aging, stress, cardiomyopathy-causing αB-crystallin mutants, and in other diseases.

MAJOR CONCLUSIONS

Depending on the context and extent of phosphorylation, αB-crystallin seems to confer beneficial or deleterious effects. Phosphorylation alters structure, stability, size distribution and dynamics of the oligomeric assembly, thus modulating chaperone activity and various cellular processes. Phosphorylated αB-crystallin has a tendency to partition to the cytoskeleton and hence to the insoluble fraction. Low levels of phosphorylation appear to be protective, while hyperphosphorylation has negative implications. Mutations in αB-crystallin, such as R120G, Q151X and 464delCT, associated with inherited myofibrillar myopathy lead to hyperphosphorylation and intracellular inclusions. An ongoing study in our laboratory with phosphorylation-mimicking mutants indicates that phosphorylation of R120GαB-crystallin increases its propensity to aggregate.

GENERAL SIGNIFICANCE

Phosphorylation of αB-crystallin has dual role that manifests either beneficial or deleterious consequences depending on the extent of phosphorylation and interaction with cytoskeleton. Considering that disease-causing mutants of αB-crystallin are hyperphosphorylated, moderation of phosphorylation may be a useful strategy in disease management. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.

Constitutive STAT3 Phosphorylation in Circulating CD4+ T Lymphocytes Associates with Disease Activity and Treatment Response in Recent-Onset Rheumatoid Arthritis

The aim of the present study was to examine constitutive signal transducer and activator of transcription 3 (STAT3) phosphorylation in circulating leukocytes as a candidate biomarker in rheumatoid arthritis (RA). 25 patients with recent-onset, untreated RA provided samples for whole blood flow cytometric determination of intracellular STAT3 phosphorylation, expressed as relative fluorescence units. The occurrence of constitutive STAT3 phosphorylation was evaluated by determining proportion of STAT3-phosphorylated cells among different leukocyte subtypes. Plasma levels of interleukin (IL)-6, IL-17 and IL-21 were measured by immunoassay, radiographs of hands and feet were examined and disease activity score (DAS28) was determined. Biomarkers were restudied and treatment response (according to European League Against Rheumatism) was determined after 12 months of treatment with disease-modifying antirheumatic drugs. At baseline, constitutive phosphorylation of STAT3 occurred in CD4⁺ T cells of 14 (56%) patients, CD8⁺ T cells of 13 (52%) patients, in CD19⁺ B cells of 7 (28%) patients, and in CD14⁺ monocytes of 12 (48%) patients. STAT3 phosphorylation levels of CD4⁺ T cells associated with DAS28, and those of all leukocyte subtypes studied associated with erosive disease. The presence of constitutive STAT3 phosphorylation in CD4⁺ T lymphocytes, pSTAT3 fluorescence intensity of CD4⁺ and CD8⁺ T cells and C-reactive protein (CRP) levels at baseline associated with good treatment response. In conclusion, constitutive STAT3 phosphorylation in circulating CD4⁺ T cells is common in recent-onset untreated RA and associates with good treatment response in patients characterized by high disease activity and the presence of systemic inflammation.

A randomized, double-blind, placebo-controlled, twelve-week, dose-ranging study of decernotinib, an oral selective JAK-3 inhibitor, as monotherapy in patients with active rheumatoid arthritis

OBJECTIVE

To assess the efficacy and safety of oral decernotinib (VX-509; Vertex Pharmaceuticals) monotherapy in a 12-week, randomized, double-blind, placebo-controlled, dose-ranging study of patients with rheumatoid arthritis (RA).

METHODS

Two hundred four adults with active RA who had been unsuccessfully treated with ≥1 disease-modifying antirheumatic drug were administered placebo tablets or decernotinib twice a day at dosages of 25 mg, 50 mg, 100 mg, or 150 mg. Primary measures of efficacy at week 12 were the response rate according to the American College of Rheumatology 20% improvement criteria (ACR20) and mean change from baseline in the Disease Activity Score in 28 joints using the C-reactive protein level (DAS28-CRP).

RESULTS

At week 12, the ACR20 response rates were 39.0%, 61.0%, 65.0%, and 65.9% in the 25-mg, 50-mg, 100-mg, and 150-mg groups, respectively, and were significantly higher in the 50-mg group (P = 0.007) and the 100-mg and 150-mg groups (P = 0.002) as compared to the response rates in the placebo group (29.3%). The mean change from baseline in DAS28-CRP was greater in the 50-mg, 100-mg, and 150-mg groups as compared to the placebo group (P < 0.001). Decernotinib treatment resulted in higher ACR50 and ACR70 response rates, more patients with DAS28-CRP scores <2.6, and improvements in the Health Assessment Questionnaire disability index as compared to placebo. The most common adverse events in any decernotinib group were nausea (6.1%), headache (4.3%), an increase in levels of alanine aminotransferase (4.3%), and hypercholesterolemia (3.7%). In the groups receiving decernotinib, there was an increased risk of infections and increased liver transaminase levels.

CONCLUSION

Decernotinib was efficacious in improving clinical signs and symptoms of RA at week 12 at dosages of 50-150 mg twice a day. Infections and increases in liver transaminase and lipid levels were noted as potential safety signals.

Signal transducer and activator of transcription (STAT) 3 inhibition delays the onset of lupus nephritis in MRL/lpr mice

The transcription factor STAT3 is overexpressed and hyperactivated in T cells from SLE patients. STAT3 plays a central role in T cell differentiation into Th17 and T follicular helper cells, two subsets that orchestrate autoimmune responses in SLE. Moreover, STAT3 is important in chemokine-mediated T cell migration. To better understand its role in SLE, we inhibited STAT3 in lupus-prone mice using the small molecule Stattic. Stattic-treated mice exhibited delayed onset of proteinuria (3 weeks later than controls), and had lower levels of anti-dsDNA antibodies and inflammatory cytokines. Inhibitor treatment reduced lymphadenopathy, resulted in a 3-fold decrease in total T cell number, and a 4-fold decrease in the numbers of T follicular helper cells. In vitro experiments showed that Stattic-treated T cells exhibited decreased proliferation and a decrease in ability to migrate to CXCL12. We propose that STAT3 inhibition represents a therapeutic target in SLE, particularly lupus nephritis.

Anti-Inflammatory Effects and Joint Protection in Collagen-Induced Arthritis after Treatment with IQ-1S, a Selective c-Jun N-Terminal Kinase Inhibitor

c-Jun N-terminal kinases (JNKs) participate in many physiologic and pathologic processes, including inflammatory diseases. We recently synthesized the sodium salt of IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime) and demonstrated that it is a high-affinity JNK inhibitor and inhibits murine delayed-type hypersensitivity. Here we show that IQ-1S is highly specific for JNK and that its neutral form is the most abundant species at physiologic pH. Molecular docking of the IQ-1S syn isomer into the JNK1 binding site gave the best pose, which corresponded to the position of cocrystallized JNK inhibitor SP600125 (1,9-pyrazoloanthrone). Evaluation of the therapeutic potential of IQ-1S showed that it inhibited matrix metalloproteinase 1 and 3 gene expression induced by interleukin-1β in human fibroblast-like synoviocytes and significantly attenuated development of murine collagen-induced arthritis (CIA). Treatment with IQ-1S either before or after induction of CIA resulted in decreased clinical scores, and joint sections from IQ-1S-treated CIA mice exhibited only mild signs of inflammation and minimal cartilage loss compared with those from control mice. Collagen II-specific antibody responses were also reduced by IQ-1S treatment. By contrast, the inactive ketone derivative 11H-indeno[1,2-b]quinoxalin-11-one had no effect on CIA clinical scores or collagen II-specific antibody titers. IQ-1S treatment also suppressed proinflammatory cytokine and chemokine levels in joints and lymph node cells. Finally, treatment with IQ-1S increased the number of Foxp3(+)CD4(+)CD25(+) regulatory T cells in lymph nodes. Thus, IQ-1S can reduce inflammation and cartilage loss associated with CIA and can serve as a small-molecule modulator for mechanistic studies of JNK function in rheumatoid arthritis.

Protein kinase CK2 enables regulatory T cells to suppress excessive TH2 responses in vivo

The quality of the adaptive immune response depends on the differentiation of distinct CD4(+) helper T cell subsets, and the magnitude of an immune response is controlled by CD4(+)Foxp3(+) regulatory T cells (Treg cells). However, how a tissue- and cell type-specific suppressor program of Treg cells is mechanistically orchestrated has remained largely unexplored. Through the use of Treg cell-specific gene targeting, we found that the suppression of allergic immune responses in the lungs mediated by T helper type 2 (TH2) cells was dependent on the activity of the protein kinase CK2. Genetic ablation of the β-subunit of CK2 specifically in Treg cells resulted in the proliferation of a hitherto-unexplored ILT3(+) Treg cell subpopulation that was unable to control the maturation of IRF4(+)PD-L2(+) dendritic cells required for the development of TH2 responses in vivo.

Small-molecule therapeutics in rheumatoid arthritis: scientific rationale, efficacy and safety

Rheumatoid arthritis (RA) remains a formidable clinical challenge. This is despite remarkable recent advances in our understanding of pathogenesis and the introduction of a variety of novel agents, particularly biologic therapeutics that are potent inhibitors of extracellular immune pathways. Whereas the latter have brought substantial improvements in efficacy and thus outcomes, there remain significant numbers of non- or partial responders to current standard of care. The discovery of key intracellular pathways, particularly kinases that subserve the function of these pivotal cytokine and immune cell receptors implicated in RA pathogenesis, has facilitated the advent of a new phase of RA drug development. Thus, a range of kinase inhibitors has entered clinical trials and one agent has been licenced for use in some regions. Herein we summarise the chequered history of kinase inhibitor development in RA, describing successes and failures alike, and thereafter examine future trends in this exciting field.

Interleukins and interleukin receptors in rheumatoid arthritis: Research, diagnostics and clinical implications

Rheumatoid arthritis (RA) is an autoimmune disease, resulting in a chronic, systemic inflammatory disorder. It may affect many tissues and organs, but it primarily affects the flexible joints. In clinical practice patient care generates many questions about diagnosis, prognosis, and treatment. It is challenging for health care specialists to keep up to date with the medical literature. This review summarizes the pathogenesis, the polymorphisms of interleukin and interleukin genes and the standard available and possible future immunologic targets for RA treatment. The identification of disease-associated interleukin and interleukin receptor genes can provide precious insight into the genetic variations prior to disease onset in order to identify the pathways important for RA pathogenesis. The knowledge of the complex genetic background may prove useful for developing novel therapies and making personalized medicine based on the individual’s genetics.

Protein kinase small molecule inhibitors for rheumatoid arthritis: Medicinal chemistry/clinical perspectives

Medicinal chemistry strategies have contributed to the development, experimental study of and clinical trials assessment of the first type of protein kinase small molecule inhibitor to target the Janus kinase/Signal Transducers and Activators of Transcription (JAK/STAT) signaling pathway. The orally administered small molecule inhibitor, tofacitinib, is the first drug to target the JAK/STAT pathway for entry into the armamentarium of the medical therapy of rheumatoid arthritis. The introduction of tofacitinib into general rheumatologic practice coupled with increasing understanding that additional cellular signal transduction pathways including the mitogen-activated protein kinase and phosphatidylinositide-3-kinase/Akt/mammalian target of rapamycin pathways as well as spleen tyrosine kinase also contribute to immune-mediated inflammatory in rheumatoid arthritis makes it likely that further development of orally administered protein kinase small molecule inhibitors for rheumatoid arthritis will occur in the near future.

P38α MAPK underlies muscular dystrophy and myofiber death through a Bax-dependent mechanism

Muscular dystrophies are a group of genetic diseases that lead to muscle wasting and, in most cases, premature death. Cytokines and inflammatory factors are released during the disease process where they promote deleterious signaling events that directly participate in myofiber death. Here, we show that p38α, a kinase in the greater mitogen-activated protein kinase (MAPK)-signaling network, serves as a nodal regulator of disease signaling in dystrophic muscle. Deletion of Mapk14 (p38α-encoding gene) in the skeletal muscle of mdx- (lacking dystrophin) or sgcd- (δ-sarcoglycan-encoding gene) null mice resulted in a significant reduction in pathology up to 6 months of age. We also generated MAPK kinase 6 (MKK6) muscle-specific transgenic mice to model heightened p38α disease signaling that occurs in dystrophic muscle, which resulted in severe myofiber necrosis and many hallmarks of muscular dystrophy. Mechanistically, we show that p38α directly induces myofiber death through a mitochondrial-dependent pathway involving direct phosphorylation and activation of the pro-death Bcl-2 family member Bax. Indeed, muscle-specific deletion of Bax, but not the apoptosis regulatory gene Tp53 (encoding p53), significantly reduced dystrophic pathology in the muscles of MKK6 transgenic mice. Moreover, use of a p38 MAPK pharmacologic inhibitor reduced dystrophic disease in Sgcd(-/-) mice suggesting a future therapeutic approach to delay disease.

Selective JAK inhibitors in development for rheumatoid arthritis

INTRODUCTION

The JAK kinases are a family of four tyrosine receptor kinases that play a pivotal role in cytokine receptor signalling pathways via their interaction with signal transducers and activators of transcription proteins. Selective inhibitors of JAK kinases are viewed as of considerable potential as disease-modifying anti-inflammatory drugs for the treatment of rheumatoid arthritis.

AREAS COVERED

This article provides a review of the clinical development and available clinical results for those JAK inhibitors currently under investigation. Phase II data for four JAK inhibitors (baricitinib, decernotinib, filgotinib and INCB-039110) are contrasted with that reported for the recently approved JAK inhibitor tofacitinib. The preclinical data on these, in addition to peficitinib, ABT-494, INCB-047986 and AC-410 are also discussed, as are some of the inhibitors in preclinical development.

EXPERT OPINION

JAK inhibitors are effective in the treatment of rheumatoid arthritis as evidenced by several inhibitors enabling the majority of treated patients to achieve ACR20 responses, with baricitinib and INCB-039110 both effective when administered once daily. JAK inhibitors differ in isoform specificity profiles, with good efficacy achievable by selective inhibition of either JAK1 (filgotinib or INCB-039110) or JAK3 (decernotinib). It remains to be seen what selectivity provides the optimal side-effect profile and to what extent inhibition of JAK2 should be avoided.

Advances in the treatment of rheumatoid arthritis

The intense pursuit of novel therapies in rheumatoid arthritis has provided physicians with an assorted set of biologic drugs to treat patients with moderate to severe disease activity. Nine different biologic therapies are currently available: seven inhibitors of pro-inflammatory cytokines (five targeting tumor necrosis factor [TNF], one interleukin [IL]-1 and one IL-6), as well as a T- and a B-lymphocyte targeting agent. All these drugs have roughly similar efficacy profiles and are approved as first- or second-line therapy in patients who failed to respond to conventional disease-modifying anti-rheumatic drugs (DMARDs) and in most cases for first line use in rheumatoid arthritis as well. Despite the irrefutable clinical and radiological benefits of biologic therapies, there are still low rates of patients achieving stable remission. Therefore, the quest for new and more effective biologic therapies continues and every year new drugs are tested. Simultaneously, optimal use of established agents is being studied in different ways. Recently, the approval of the first small molecule targeting intracellular pathways has opened a new chapter in the treatment of rheumatoid arthritis. Other emerging treatment strategies include the activation of regulatory T cells as well as new cytokine-targeting therapies.

14-3-3η is a novel mediator associated with the pathogenesis of rheumatoid arthritis and joint damage

Introduction

The aim of this study was to investigate whether 14-3-3η, a specific isoform of a family of proteins regulating processes such as cellular signalling, activates cell-signalling pathways and induces factors known to contribute to the pathophysiology of rheumatoid arthritis (RA). We also investigated whether 14-3-3η is associated with more severe disease in both early and established RA.

Methods

We investigated the effect of 14-3-3η on the activation of RA-relevant signalling cascades and induction of proinflammatory mediators that contribute to the joint damage process. 14-3-3η titres from 33 patients with early RA (mean RA duration = 1.8 months) and from 40 patients with established RA were measured in serum drawn at the 3-year time point of the Behandel Strategieën study. The relationship between 14-3-3η titres and standard clinical variables was investigated by correlation analysis. The association with radiographic damage and radiographic progression over at least a 2-year period was investigated using univariate and multivariate regression analyses.

Results

14-3-3η activated selected members of the mitogen-activated protein kinase (MAPK) family, mainly extracellular regulated kinase 1/2 and c-Jun kinase, but not p38MAPK. Activation by 14-3-3η, using levels spanning the concentration range found in RA patient serum, resulted in the induction of inflammatory transcripts such as interleukin 1 (IL-1) and IL-6 and factors linked to the joint damage process, such as receptor activator of nuclear factor κB ligand and matrix metalloproteinase 1. Serum 14-3-3η correlated significantly with rheumatoid factor (RF) (r = 0.43) and anticitrullinated protein antibodies (ACPAs) (r = 0.31) in the early RA cohort, but not with C-reactive protein (CRP) or the Disease Activity Score in 28 joints in either cohort. Serum 14-3-3η concentrations were significantly higher in patients with radiographically assessed joint damage and in those who had radiographic progression. By multivariate analysis, we show that 14-3-3η complemented markers such as CRP, RF and ACPA in informing RA radiographic status and/or progression.

Conclusions

Extracellular 14-3-3η activates key signalling cascades and induces factors associated with the pathogenesis of RA at concentrations found in patients with RA, and its expression is higher in patients with radiographic damage and RA progression.

Current immunotherapy in rheumatoid arthritis

Rheumatoid arthritis is a common autoimmune disease primarily manifesting as chronic synovitis, subsequently leading to a change in joint integrity. Progressive disability and systemic complications are strongly associated with a decreased quality of life. To maintain function and health in patients with rheumatoid arthritis, early, aggressive and guided immunosuppressive therapy is required to induce clinical remission. Antirheumatic drugs are capable of controlling synovial inflammation and are therefore named 'disease-modifying antirheumatic drugs' (DMARDs). This article aims to bridge the beginning of DMARD therapy with agents such as methotrexate, leflunomide, sulfasalazine, injectable gold and (hydroxy)chloroquine with biological therapies, and with the new era of kinase inhibitors. Mechanisms of action, as well as advantages and disadvantages of DMARDs, are discussed with respect to the current literature and current recommendations.

Dual kinase-bromodomain inhibitors for rationally designed polypharmacology

Concomitant inhibition of multiple cancer-driving kinases is an established strategy to improve the durability of clinical responses to targeted therapies. The difficulty of discovering kinase inhibitors with an appropriate multi-target profile has, however, necessitated the application of combination therapies, which can pose significant clinical development challenges. Epigenetic reader domains of the bromodomain family have recently emerged as novel targets for cancer therapy. Here we report that several clinical kinase inhibitors also inhibit bromodomains with therapeutically relevant potencies and are best classified as dual kinase/bromodomain inhibitors. Nanomolar activity on BRD4 by BI-2536 and TG-101348, clinical PLK1 and JAK2/FLT3 kinase inhibitors, respectively, is particularly noteworthy as these combinations of activities on independent oncogenic pathways exemplify a novel strategy for rational single agent polypharmacological targeting. Furthermore, structure-activity relationships and co-crystal structures identify design features that enable a general platform for the rational design of dual kinase/bromodomain inhibitors.

Therapeutic targets for rheumatoid arthritis: Progress and promises

Recent therapeutic advancements in understanding of molecular and cellular mechanisms of rheumatoid arthritis (RA) have highlighted the strategies that aim to inhibit the harmful effects of up-regulated cytokines or other inflammatory mediators and to inhibit their associated signaling events. The utility of cytokine as therapeutic targets in RA has been unequivocally demonstrated by the success of tumor necrosis factor (TNF)-α blockade in clinical practice. Partial and non-responses to TNF-α blocking agents, however, together with the increasing clinical drive to remission induction, requires that further therapeutic targets be identified. Numerous proinflammatory mediators with their associated cell signaling events have now been demonstrated in RA, including interleukin (IL)-1 and IL-12 superfamilies. Continued efforts are ongoing to target IL-6, IL-15 and IL-17 in clinical trials with promising data emerging. In the present review, we focus on IL-7, IL-18, IL-32 and IL-10 family of cytokines (IL-19, IL-20 and IL-22) as they are implicated in contributing to the pathogenesis of RA, which could be targeted and offer new therapeutic options for RA therapy. Recent evidences also suggest that multiligand receptor for advanced glycation end products (RAGE), several adipokines and various components of immune system play a critical role in the pathophysiology of RA; therefore we have also highlighted them as therapeutic targets for RA therapy. Components of subcellular pathways, involve in nuclear transcription factor (NF)-κB, mitogen-activated protein kinases (MAPKs) and the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway have also been discussed and offer several novel potential therapeutic opportunities for RA.

Epigallocatechin-3-gallate modulates anti-oxidant defense enzyme expression in murine submandibular and pancreatic exocrine gland cells and human HSG cells

Sjogren's syndrome (SS) and type-1 diabetes are prevalent autoimmune diseases in the USA. We reported previously that epigallocatechin-3-gallate (EGCG) prevented and delayed the onset of autoimmune disease in non-obese diabetic (NOD) mice, a model for both SS and type-1 diabetes. EGCG also normalized the levels of proteins related to DNA repair and anti-oxidant activity in NOD.B10.Sn-H2 mice, a model for primary SS, prior to disease onset. The current study examined the effect of EGCG on the expression of anti-oxidant enzymes in the submandibular salivary gland and the pancreas of NOD mice and cultured human salivary gland acinar cells. NOD mice consuming 0.2% EGCG daily dissolved in water showed higher protein levels of peroxiredoxin 6 (PRDX6), a major anti-oxidant defense protein, and catalase, while the untreated NOD mice exhibited significantly lowered levels of PRDX6. Similarly, pancreas samples from water-fed NOD mice were depleted in PRDX6 and superoxide dismutase, while EGCG-fed mice showed high levels of these anti-oxidant enzymes. In cultured HSG cells EGCG increased PRDX6 levels significantly, and this was inhibited by p38 and JNK inhibitors, suggesting that the EGCG-mediated increase in protective anti-oxidant capacity is regulated in part through mitogen-activated protein kinase pathway signaling. This mechanism may explain the higher levels of PRDX6 found in EGCG-fed NOD mice. These preclinical observations warrant future preclinical and clinical studies to determine whether EGCG or green tea polyphenols could be used in novel preventive and therapeutic approaches against autoimmune diseases and salivary dysfunction involving oxidative stress.

Fate of lymphocytes after withdrawal of tofacitinib treatment

Tofacitinib (Tofa) is an inhibitor of Janus Kinase 3, developed for the treatment of autoimmune diseases and for the prevention of transplant rejection. Due to its selective action on proliferating cells, Tofa can offer a way to block T cell activation, without toxic effects on resting cells. However, few studies have investigated the effects of Tofa on lymphocyte activation in vitro. Our aim was to study the action of Tofa on different lymphocyte subsets after in vitro stimulation and to track the behaviour of treated cells after interruption of the treatment. Peripheral blood lymphocytes were stimulated in vitro with mitogen and treated with two concentrations of Tofa. After a first period in culture, cells were washed and further incubated for an additional time. Lymphocyte subsets, activation phenotype and proliferation were assessed at the different time frames. As expected, Tofa was able to reduce the activation and proliferation of lymphocytes in the first four days of treatment. In addition the drug led to a relative decrease of Natural Killer, B cells and CD8 T cells compared to CD4 T cells. However, treated cells were still viable after the first period in culture and begun to proliferate, strikingly, in a dose dependent manner when the drug was removed from the environment by replacing the culture medium. This novel data does not necessarily predict a similar behaviour in vivo, but can warn about the clinical use of this drug when a discontinuation of treatment with Tofa is considered for any reason.

Cytotoxic-T-lymphocyte antigen 4 receptor signaling for lymphocyte adhesion is mediated by C3G and Rap1

T-lymphocyte adhesion plays a critical role in both inflammatory and autoimmune responses. The small GTPase Rap1 is the key coordinator mediating T-cell adhesion to endothelial cells, antigen-presenting cells, and virus-infected cells. We describe a signaling pathway, downstream of the cytotoxic T-lymphocyte antigen 4 (CTLA-4) receptor, leading to Rap1-mediated adhesion. We identified a role for the Rap1 guanine nucleotide exchange factor C3G in the regulation of T-cell adhesion and showed that this factor is required for both T-cell receptor (TCR)-mediated and CTLA-4-mediated T-cell adhesion. Our data indicated that C3G translocates to the plasma membrane downstream of TCR signaling, where it regulates activation of Rap1. We also showed that CTLA-4 receptor signaling mediates tyrosine phosphorylation in the C3G protein, and that this is required for augmented activation of Rap1 and increased adhesion mediated by leukocyte function-associated antigen type 1 (LFA-1). Zap70 is required for C3G translocation to the plasma membrane, whereas the Src family member Hck facilitates C3G phosphorylation. These findings point to C3G and Hck as promising potential therapeutic targets for the treatment of T-cell-dependent autoimmune disorders.

Involvement of Mincle and Syk in the changes to innate immunity after ischemic stroke

Accumulating evidence shows that post-ischemic inflammation originated by Toll-like receptors (TLR) plays critical roles in ischemic stroke. However, the functions of other innate immune receptors are poorly understood in cerebral ischemia. Macrophage-inducible C-type lectin, Mincle, is one of the innate immune receptor C-type lectin-like receptor (CLR) to response against dying cells. In the present study, we showed that Mincle, its ligand SAP130, and its downstream phospho-Syk/Syk were upregulated after ischemia, and that Mincle is expressed in immune and non-immune cells in the ischemic brains of mice and human. We treated mice with piceatannol, a Syk inhibitor, and consequently the infarct volume and swelling were suppressed by piceatannol. The levels of phospho-Syk, MMP9 and ICAM-1 were downregulated, and the level of Claudin5 was uplegurated in piceatannol-treated groups. These data indicate that innate immune system, such as Mincle and Syk plays a pivotal role in the pathogenesis after the ischemia and reperfusion.

Glucocorticoid sensitivity in health and disease

Glucocorticoids regulate many physiological processes and have an essential role in the systemic response to stress. For example, gene transcription is modulated by the glucocorticoid-glucocorticoid receptor complex via several mechanisms. The ultimate biologic responses to glucocorticoids are determined by not only the concentration of glucocorticoids but also the differences between individuals in glucocorticoid sensitivity, which is influenced by multiple factors. Differences in sensitivity to glucocorticoids in healthy individuals are partly genetically determined by functional polymorphisms of the gene that encodes the glucocorticoid receptor. Hereditary syndromes have also been identified that are associated with increased and decreased sensitivity to glucocorticoids. As a result of their anti-inflammatory properties, glucocorticoids are widely used in the treatment of allergic, inflammatory and haematological disorders. The variety in clinical responses to treatment with glucocorticoids reflects the considerable variation in glucocorticoid sensitivity between individuals. In immune-mediated disorders, proinflammatory cytokines can induce localized resistance to glucocorticoids via several mechanisms. Individual differences in how tissues respond to glucocorticoids might also be involved in the predisposition for and pathogenesis of the metabolic syndrome and mood disorders. In this Review, we summarize the mechanisms that influence glucocorticoid sensitivity in health and disease and discuss possible strategies to modulate glucocorticoid responsiveness.

Efficacy and safety of tofacitinib in the treatment of rheumatoid arthritis: a systematic review and meta-analysis

BACKGROUND

Tofacitinib is a disease-modifying antirheumatic drug (DMARD) which was recently approved by US Food and Drug Administration (FDA). There are several randomised clinical trials (RCTs) that have investigated the efficacy and safety of tofacitinib in adult patients with rheumatoid arthritis (RA). A systematic review with a meta-analysis of RCTs was undertaken to determine the efficacy and safety of tofacitinib in treating patients with RA.

METHODS

Electronic and clinical trials register databases were searched for published RCTs of tofacitinib between 2009 and 2013. Outcomes of interest include 20% and 50% improvement in the American College of Rheumatology Scale (ACR20 and ACR50) response rates, rates of infection, the number of immunological/haematological adverse events (AEs), deranged laboratory results (hepatic, renal, haematological tests and lipoprotein level) and the incidence of drug withdrawal.

RESULTS

Eight RCTs (n = 3,791) were reviewed. Significantly greater ACR20 response rates were observed in patients receiving tofacitinib 5 and 10 mg bid (twice daily) versus placebo at week 12, with risk ratios (RR) of 2.20 (95% CI 1.58, 3.07) and 2.38 (95% CI 1.81, 3.14) respectively. The effect was maintained at week 24 for 5 mg bid (RR 1.94; 95% CI 1.55, 2.44) and 10 mg bid (RR 2.20; 95% CI 1.76, 2.75). The ACR50 response rate was also significantly higher for patients receiving tofacitinib 5 mg bid (RR 2.91; 95% CI 2.03, 4.16) and 10 mg bid (RR 3.32; 95% CI 2.33, 4.72) compared to placebo at week 12. Patients in the tofacitinib group had significantly lower mean neutrophil counts, higher serum creatinine, higher percentage change of LDL/HDL and a higher risk of ALT/AST > 1 ULN (upper limit of normal) versus placebo. There were no significant differences in AEs and withdrawal due to AEs compared to placebo.

CONCLUSION

Tofacitinib is efficacious and well tolerated in patients with MTX-resistant RA up to a period of 24 weeks. However, haematological, liver function tests and lipoproteins should be monitored. Long-term efficacy and pharmacovigilance studies are recommended.

Biology of chronic lymphocytic leukemia in different microenvironments: clinical and therapeutic implications

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of mature monoclonal B cells in peripheral blood, bone marrow, spleen, and lymph nodes. The trafficking, survival, and proliferation of CLL cells is tightly regulated by the surrounding tissue microenvironment and is mediated by antigenic stimulation, close interaction with various accessory cells and exposure to different cytokines, chemokines, and extracellular matrix components. In the last decade there have been major advances in the understanding of the reciprocal interactions between CLL cells and the various microenvironmental compartments. This article discusses the role of the microenvironment in the context of efforts to develop novel therapeutics that target the biology of CLL.

From immunosuppression to immunomodulation: current principles and future strategies

Over the last few decades, tremendous progress has been made in understanding the mechanisms of immune responses. This progress has also led to a more detailed knowledge of the processes leading to the loss of self-tolerance and the destruction of self-tissue in the case of autoimmune diseases, the effector mechanism involved in transplant allograft rejection as well as the driving factors in exacerbated inflammatory disorders. Despite this progress, the challenge still remains to selectively interfere with immune responses responsible for autoimmunity or transplant rejection while keeping an intact response to infectious agents. To date, such a selective interference is still difficult to achieve, as highlighted by the fact that an overall increased risk for infections and malignancy continues to be the most frequent side effect of the currently used immunosuppressive principles. Nevertheless, although discovered several decades ago, many of the 'first-generation' immunosuppressive principles such as steroids, methotrexate and cyclosporin A are still in clinical use, demonstrating the therapeutic value of these drugs for the patients that are in need. In this review, the author describes the mode of action of the currently most used immunosuppressive agents (not attempting to cover all principles that are available) and expands on recent activities in the discovery and development of novel immunomodulatory principles.

Oral janus kinase inhibitor for the treatment of rheumatoid arthritis: tofacitinib

Since the introduction of immune modulators in the treatment of rheumatoid arthritis (RA), there has been hope that orally effective biologic agents would be developed. Tofacitinib, a Janus kinase inhibitor, has become the first oral biologic to receive approval for use in active RA patients. This paper reviews the efficacy and safety profile of Tofacitinib at dosages of 5 mg and 10 mg twice daily. Remarkable improvement in terms of ACR 20 response and HAQ-DI score was noted at month 3 and month 6. DAS 28-4 ESR < 2.6 achievement was noticeably obvious at month 6 for both dosages. No significant serious adverse events, serious infections, neutropenia, or anaemia were observed compared to placebo. In fact, Tofacitinib 5 mg was even found to have significant protective effect of anaemia in the meta-analysis (P = 0.004). Tofacitinib has a noticeable efficacy in controlling disease activity in RA with a manageable safety profile. However, longer studies are needed for its long-term safety profile.

Future trends for unicompartmental arthritis of the knee: injectables & stem cells

Arthritis is one of the most frequent musculoskeletal problems, causing pain, disability, and a significant economic burden. In this article, we discuss current nonsurgical injectable treatment options as well as future trends for cartilage lesions and early arthritis of the knee. We cover some potential treatments for knee osteoarthritis, including stem cell and gene therapies.

Polo-like kinase 1 is overexpressed in renal cancer and participates in the proliferation and invasion of renal cancer cells

Polo-like kinase 1 (Plk1) is an interesting molecule both as a biomarker and as a target for highly specific cancer therapy for several reasons. However, the functional significance of Plk1 in renal cell carcinoma (RCC) has not been reported. To explore whether Plk1 plays a general role in renal carcinoma, we examined the expression of Plk1 protein in renal urothelial carcinoma and cell lines, and analyzed the relationship between Plk1 protein expression and development, proliferation, and invasion of renal carcinoma. Immunohistochemisty was used to detect the expression of Plk1 in 100 renal carcinoma tissues. Moreover, the expression of Plk1 was analyzed by western blot and real-time polymerase chain reaction (PCR) in 80 renal carcinoma tissues and 20 normal renal tissues. CCK-8 assay, colony formation assay, and Transwell assay were used to examine proliferation and invasion ability of renal cancer cells with treatment of scytonemin (the specific inhibitor of Plk1). Statistical analysis was used to discuss the association between Plk1 expression and clinicopathologic parameters, and proliferation and invasion ability of renal cancer cells. Plk1 expressions were greater in cancerous tissues than in normal tissues (P<0.05). With an increase in tumor grade and stage, tumor metastasis, and recurrence, the level of Plk1 increased significantly in renal cancerous tissues. Moreover, there was a significantly higher expression of Plk1 in higher degree of malignant renal adenocarcinoma cell ACHN than that in renal adenocarcinoma cell 769-P. With increasing concentration of scytonemin, we found that cell proliferation and invasion activity decreased significantly. Plk1 expression status was closely correlated with important histopathologic characteristics (grades, stages, metastasis, and recurrence) of renal carcinomas. Furthermore, Plk1 played an important function on renal cancer cells' proliferation and invasion.

Safety profile of protein kinase inhibitors in rheumatoid arthritis: systematic review and meta-analysis

OBJECTIVE

To summarise the adverse events (AE) reported in patients with rheumatoid arthritis (RA) treated with protein kinase inhibitors (PKi), and identify family and molecule-related AEs.

METHODS

Systematic review of the PKi used in clinical trials (CTs) in RA. Medline, Embase, Cochrane Library, Web of Knowledge, and international abstracts of congress were reviewed, (up to 31 October 2012). Search was limited to interventional studies of PKi used in CTs in RA, written in English, and reporting frequencies of AE. Diseases with similar comorbidity burden also were included. Frequency of AE, serious AE (SAE), death and discontinuation due to  AEs (DCAE) were recorded. Risk of bias was assessed. Meta-analysis was carried using pooled relative risk (RR) with 95% CI as effect measure.

RESULTS

The search produced 4410 hits. Forty-one articles reporting data on 21 PKi of the Janus kinase (JAK), SYK, p38 and cKit families were selected for detailed analysis. In patients treated with p38 inhibitors, RR for dizziness was 2.36 (1.20 to 4.63), and in patients treated with c-Kit inhibitors, RR for oedema was 3.43 (1.58 to 7.42). In patients treated with the JAK inhibitor tofacitinib, RR for hypercholesterolaemia was 1.70 (1.10 to 2.63) that was dose related. In patients treated with the Syk inhibitor fostamatinib, pooled RR for hypertransaminasaemia, hypertension, diarrhoea and neutropenia were 2.93 (1.02 to 8.43), 2.80 (1.58 to 5.99), 5.20 (3.19 to 8.49) and 9.24 (2.22 to 38.42), respectively. Serious infections and malignancies were not significantly more frequent in PKi-treated patients than in comparator groups.

CONCLUSIONS

Event rates of serious infections and malignancies with PKi are not different from biologics. In addition, PKi have a unique safety profile related to target and off-target inhibition of kinases, at times dose related.