April 2014

Molecular pathways: Molecular basis for sensitivity and resistance to JAK inhibitors

Clin Cancer Research doi:10.1158/1078-0432.CCR-13-0279

Janus kinases (JAKs) mediate the regulation of a variety of cytokine signals with alterations in JAK1, JAK2, JAK3 and Tyk2 signalling contributing to many disease states including autoimmune diseases and haematological malignancies. Recently tofacitinib and ruxolitinib have been approved for treatment for rheumatoid arthritis and myelofibrosis respectively. Several JAK2 inhibitors, such as momelotinib and pacritinib, currently in development for myelofibrosis and the JAK1/2 inhibitor baricitinib...

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January 2014

PI3K-δ and PI3K-γ inhibition by IPI-145 abrogates immune responses and suppresses activity in autoimmune and inflammatory disease models

Chemistry and Biology Nov 13 20, 1364-1374

Phosphoinositide-3 kinases (PI3K) are cell signalling proteins that act as a central node for relaying signals from cell surface receptors and downstream mediators. Specifically they phosphorylate phosphatidylinositol to phosphatidylinositol-3,4,5-trisphosphate (PIP3). This acts a docking site for signalling proteins, leading to the activation of downstream effectors such as BTK. Therefore, inhibition of the PI3K-d and PI3K-? isoforms (PI3K-a and PI3K-ß demonstrated embryonic lethality in murine...

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Selective inhibition of spleen tyrosine kinase (SYK) with a novel orally bioavailable small molecule inhibitor, RO9021, impinges on various innate and adaptive immune responses: implication for SYK inhibitors in autoimmune disease therapy

Arthritis Research and Therapy 2013 15:R146

Spleen tyrosine kinase (SYK) has already been described as a potential therapeutic target for the treatment of autoimmune diseases. Previously the SYK inhibitor fostamatinib was in clinical development for the treatment of rheumatoid arthritis, but has since been suspended. However, investigation into SYK inhibition continues with RO2091, a novel ATP-competitive inhibitor of SYK with reasonable selectivity, potency and oral bioavailability which has been shown to suppress various innate and adap...

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November 2013

Therapeutic Targeting of the JAK/STAT Pathway

Basic Clin Pharmacol Toxicol. 2013 Oct 24. doi: 10.1111/bcpt.12164

The inhibition of the JAK/STAT pathway has proven to be a powerful therapeutic tool in the treatment of autoimmune diseases. The authors review the role of the JAK/STAT pathway in human disease, including the role of mutations in defective function of this pathway. They discuss the rationale behind JAK inhibition and review the two JAK inhibitors currently approved by the FDA for clinical use; tofacitinib, for the treatment of RA, and ruxolitinib, for the treatment of polycythaemia vera and myel...

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September 2013

Inhibitors of switch kinase ‘spleen tyrosine kinase’ in inflammation and immune-mediated disorders: A review

European Journal of Medicinal Chemistry 2013 67:434–446

SYK plays a significant role in the immune cell signalling of B cells, mast cells, macrophages and neutrophils. Kaur et al. provide a comprehensive review of the molecule, its role in autoimmune disease and clinical data on its inhibition. The paper covers the basic chemistry of SYK including structure, mechanism of action, synthetic derivatives and function, and the relevance of SYK as a therapeutic target for many autoimmune diseases is discussed. The SYK inhibitors currently in clinical trial...

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August 2013

Targeting the SYK-BTK axis for the treatment of immunological and hematological disorders: recent progress and therapeutic perspectives

Pharmacol Ther. 2013 May; 138(2):294–309

This review focuses on targeting spleen tyrosine kinase (SYK) and Bruton’s tyrosine kinase (BTK) inhibitors as potential immunomodulatory agents for the treatment of autoimmune and inflammatory disorders with SYK inhibition showing encouraging efficacy in patients with RA. The paper describes the role of SYK and BTK in several therapy areas including autoimmune diseases, allergic inflammatory disorders and haematological cancers as well as their role in innate immunity and regulators of adaptive...

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June 2013

Janus kinases in immune cell signaling

Immunological Reviews 2009; 228:273-87

This review from 2009 describes the Janus Kinases (JAK) that includes JAK1, JAK2, and JAK3, a subgroup of non-receptor protein tyrosine kinases. This protein family has a diverse range of functions including roles in cell growth, survival, development, and differentiation of a variety of cells, and especially immune and haematopoietic cells. Current knowledge of protein structure, regulatory mechanisms, signalling pathways and intracellular interactions for the JAK family is reviewed. The paper ...

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Back to the future: oral targeted therapy for RA and other autoimmune diseases

Nature Reviews Rheumatology 2013; 9(3):173-82

This review paper considers how advances in understanding of the disease process underlying rheumatoid arthritis (RA) and the development of novel techniques have transformed the management of this progressively disabling condition. Physicians are no longer limited to prescribing symptomatic treatments such as non-steroidal anti-inflammatory drugs (NSAIDs) or choosing from a seemingly random array of drugs drawn from multiple disciplines, such as methotrexate and sulphasalazine, which are descri...

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Janus kinases inhibitors in autoimmune diseases

Annals of the Rheumatic Diseases 2013; 72:ii111-ii115

This review describes the role of various cytokines in rheumatoid arthritis (RA) and related diseases. This includes an overview of the different types of cytokine receptors including type I, which bind some of the interleukins (ILs), colony stimulating factors (CSFs) and hormones such as erythropoietin, prolactin and growth hormone (GH); and type II, which bind to interferons and IL-10-related proteins. In addition, the cytoplasmic domain of type I and II cytokine receptors bind to members of a...

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Inflammation and bone erosion are suppressed in models of rheumatoid arthritis following treatment with a novel Syk inhibitor

Clinical Immunology 2007; 124:244-57

This study investigated the capacity of the novel oral spleen tyrosine kinase (Syk) inhibitor R406, and its prodrug R788 (fostamatinib), to suppress the reversed passive Arthrus reaction (RPA) and collagen-induced arthritis (CIA) in rats. R406 (0.1, 1, 5 and 10 mg/kg) and R788 (10 and 30 mg/kg) reduced the cutaneous RPA reaction and inflammatory oedema in a dose-dependent manner, with statistically significant reductions in extravascular leakage and tissue swelling (72% reduction with R406 10 mg...

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