-
Signal Transduction and Targeted Therapy May 2023The Janus kinase (JAK) signal transducer and activator of transcription (JAK-STAT) pathway is an evolutionarily conserved mechanism of transmembrane signal transduction... (Review)
Review
The Janus kinase (JAK) signal transducer and activator of transcription (JAK-STAT) pathway is an evolutionarily conserved mechanism of transmembrane signal transduction that enables cells to communicate with the exterior environment. Various cytokines, interferons, growth factors, and other specific molecules activate JAK-STAT signaling to drive a series of physiological and pathological processes, including proliferation, metabolism, immune response, inflammation, and malignancy. Dysregulated JAK-STAT signaling and related genetic mutations are strongly associated with immune activation and cancer progression. Insights into the structures and functions of the JAK-STAT pathway have led to the development and approval of diverse drugs for the clinical treatment of diseases. Currently, drugs have been developed to mainly target the JAK-STAT pathway and are commonly divided into three subtypes: cytokine or receptor antibodies, JAK inhibitors, and STAT inhibitors. And novel agents also continue to be developed and tested in preclinical and clinical studies. The effectiveness and safety of each kind of drug also warrant further scientific trials before put into being clinical applications. Here, we review the current understanding of the fundamental composition and function of the JAK-STAT signaling pathway. We also discuss advancements in the understanding of JAK-STAT-related pathogenic mechanisms; targeted JAK-STAT therapies for various diseases, especially immune disorders, and cancers; newly developed JAK inhibitors; and current challenges and directions in the field.
Topics: Humans; Janus Kinases; Signal Transduction; Janus Kinase Inhibitors; STAT Transcription Factors; Autoimmune Diseases; Neoplasms; Cytokines; Cognition
PubMed: 37208335
DOI: 10.1038/s41392-023-01468-7 -
Science (New York, N.Y.) Sep 2022Drug resistance in cancer is often linked to changes in tumor cell state or lineage, but the molecular mechanisms driving this plasticity remain unclear. Using murine...
Drug resistance in cancer is often linked to changes in tumor cell state or lineage, but the molecular mechanisms driving this plasticity remain unclear. Using murine organoid and genetically engineered mouse models, we investigated the causes of lineage plasticity in prostate cancer and its relationship to antiandrogen resistance. We found that plasticity initiates in an epithelial population defined by mixed luminal-basal phenotype and that it depends on increased Janus kinase (JAK) and fibroblast growth factor receptor (FGFR) activity. Organoid cultures from patients with castration-resistant disease harboring mixed-lineage cells reproduce the dependency observed in mice by up-regulating luminal gene expression upon JAK and FGFR inhibitor treatment. Single-cell analysis confirms the presence of mixed-lineage cells with increased JAK/STAT (signal transducer and activator of transcription) and FGFR signaling in a subset of patients with metastatic disease, with implications for stratifying patients for clinical trials.
Topics: Androgen Antagonists; Animals; Cell Plasticity; Drug Resistance, Neoplasm; ErbB Receptors; Humans; Janus Kinase Inhibitors; Janus Kinases; Male; Mice; Neoplasms, Experimental; Organoids; Prostatic Neoplasms; STAT Transcription Factors; Signal Transduction
PubMed: 35981096
DOI: 10.1126/science.abn0478 -
Drugs Mar 2023In recent years, better knowledge of the pathophysiology of inflammatory bowel diseases (IBD) has led to a relevant expansion of the therapeutic arsenal for these... (Review)
Review
In recent years, better knowledge of the pathophysiology of inflammatory bowel diseases (IBD) has led to a relevant expansion of the therapeutic arsenal for these conditions. Janus kinase (JAK) inhibitors are a family of small molecules that block one or more of the intracellular tyrosine kinases, including JAK-1, JAK-2, JAK-3 and TYK-2. Tofacitinib, a non-selective small molecule JAK inhibitor, and upadacitinib and filgotinib, which are selective JAK-1 inhibitors, have been approved by the US Food and Drug Administration (FDA) for moderate-to-severe active ulcerative colitis. Compared to biological drugs, JAK inhibitors have a short half-life, rapid onset of action, and no immunogenicity. Both clinical trials and real-world evidence support the use of JAK inhibitors in the treatment of IBD. However, these therapies have been linked with multiple adverse events (AEs) including infection, hypercholesterolemia, venous thromboembolism, major adverse cardiovascular events, and malignancy. While early studies recognized several potential AEs, post-marketing trials have shown that tofacitinib may increase the risk of thromboembolic diseases and major cardiovascular events. The latter are seen in patients aged 50 years or older with cardiovascular risk factors. Hence, the benefits of treatment and risk stratification need to be considered when positioning tofacitinib. Novel JAK inhibitors with a more selective effect on JAK-1 have proven to be effective in both Crohn's disease and ulcerative colitis, offering a potentially safer and efficacious therapeutic option to patients, including those with previous non-response to other therapies such as biologics. Nevertheless, long-term effectiveness and safety data are required.
Topics: Humans; Janus Kinase Inhibitors; Colitis, Ulcerative; Inflammatory Bowel Diseases; Crohn Disease; Cardiovascular Diseases; Janus Kinases
PubMed: 36913180
DOI: 10.1007/s40265-023-01840-5 -
Anais Brasileiros de Dermatologia 2023The JAK-STAT signaling pathway mediates important cellular processes such as immune response, carcinogenesis, cell differentiation, division and death. Therefore, drugs... (Review)
Review
The JAK-STAT signaling pathway mediates important cellular processes such as immune response, carcinogenesis, cell differentiation, division and death. Therefore, drugs that interfere with different JAK-STAT signaling patterns have potential indications for various medical conditions. The main dermatological targets of JAK-STAT pathway inhibitors are inflammatory or autoimmune diseases such as psoriasis, vitiligo, atopic dermatitis and alopecia areata; however, several dermatoses are under investigation to expand this list of indications. As JAK-STAT pathway inhibitors should gradually occupy a relevant space in dermatological prescriptions, this review presents the main available drugs, their immunological effects, and their pharmacological characteristics, related to clinical efficacy and safety, aiming to validate the best dermatological practice.
Topics: Humans; Janus Kinase Inhibitors; Janus Kinases; Dermatology; Signal Transduction; STAT Transcription Factors; Vitiligo
PubMed: 37230920
DOI: 10.1016/j.abd.2023.03.001 -
Frontiers in Immunology 2019Autoimmune skin diseases are characterized by significant local and systemic inflammation that is largely mediated by the Janus kinase (JAK)-signal transducer and... (Review)
Review
Autoimmune skin diseases are characterized by significant local and systemic inflammation that is largely mediated by the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. Advanced understanding of this pathway has led to the development of targeted inhibitors of Janus kinases (JAKinibs). As a class, JAK inhibitors effectively treat a multitude of hematologic and inflammatory diseases. Growing evidence suggests that JAK inhibitors are efficacious in atopic dermatitis, alopecia areata, psoriasis, and vitiligo. Additional evidence suggests that JAK inhibition might be broadly useful in dermatology, with early reports of efficacy in several other conditions. JAK inhibitors can be administered orally or used topically and represent a promising new class of medications. Here we review the evolving data on the role of the JAK-STAT pathway in inflammatory dermatoses and the potential therapeutic benefit of JAK-STAT antagonism.
Topics: Autoimmune Diseases; Humans; Janus Kinase Inhibitors; Janus Kinases; STAT Transcription Factors; Signal Transduction; Skin Diseases
PubMed: 31649667
DOI: 10.3389/fimmu.2019.02342 -
International Journal of Molecular... Feb 2023The Janus kinase (Jak)/signal transducer and activating protein (STAT) pathways mediate the intracellular signaling of cytokines in a wide spectrum of cellular... (Review)
Review
The Janus kinase (Jak)/signal transducer and activating protein (STAT) pathways mediate the intracellular signaling of cytokines in a wide spectrum of cellular processes. They participate in physiologic and inflammatory cascades and have become a major focus of research, yielding novel therapies for immune-mediated inflammatory diseases (IMID). Genetic linkage has related dysfunction of Tyrosine kinase 2 (Tyk2)-the first member of the Jak family that was described-to protection from psoriasis. Furthermore, Tyk2 dysfunction has been related to IMID prevention, without increasing the risk of serious infections; thus, Tyk2 inhibition has been established as a promising therapeutic target, with multiple Tyk2 inhibitors under development. Most of them are orthosteric inhibitors, impeding adenosine triphosphate (ATP) binding to the JH1 catalytic domain-which is highly conserved across tyrosine kinases-and are not completely selective. Deucravacitinib is an allosteric inhibitor that binds to the pseudokinase JH2 (regulatory) domain of Tyk2; this unique mechanism determines greater selectivity and a reduced risk of adverse events. In September 2022, deucravacitinib became the first Tyk2 inhibitor approved for the treatment of moderate-to-severe psoriasis. A bright future can be expected for Tyk2 inhibitors, with newer drugs and more indications to come.
Topics: Humans; TYK2 Kinase; Janus Kinases; Psoriasis
PubMed: 36834806
DOI: 10.3390/ijms24043391 -
Frontiers in Immunology 2023Autoimmune bullous disease (AIBD) is a severe skin disorder caused by autoantibodies that target intercellular or cell-matrix adhesion proteins. Currently, the preferred... (Review)
Review
Autoimmune bullous disease (AIBD) is a severe skin disorder caused by autoantibodies that target intercellular or cell-matrix adhesion proteins. Currently, the preferred treatment for AIBD involves the use of glucocorticoids or traditional immunosuppressants. Additionally, the utilization of biological agents such as rituximab, omalizumab, and dupilumab is on the rise. However, effectively managing AIBD remains a challenge. The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway has been implicated in various inflammatory diseases. In recent years, a range of drugs known as JAK inhibitors, which target this pathway, have been developed. Several studies have explored the efficacy and safety of JAK inhibitors for treating AIBD. Consequently, this review begins by examining the role of the JAK/STAT pathway in AIBD, summarizing the application of different JAK inhibitors in AIBD treatment, and emphasizing the importance of disease management in treating AIBD with JAK inhibitors. Furthermore, it highlights the need for a better understanding of the JAK/STAT pathway's role in AIBD, as well as the effectiveness and safety of JAK inhibitors for treating this disease.
Topics: Humans; Janus Kinase Inhibitors; Janus Kinases; STAT Transcription Factors; Signal Transduction; Autoimmune Diseases; Skin Diseases, Vesiculobullous
PubMed: 37492565
DOI: 10.3389/fimmu.2023.1220887 -
Nature Reviews. Rheumatology Mar 2022The four Janus kinase (JAK) proteins and seven signal transducer and activator of transcription (STAT) transcription factors mediate intracellular signal transduction... (Review)
Review
The four Janus kinase (JAK) proteins and seven signal transducer and activator of transcription (STAT) transcription factors mediate intracellular signal transduction downstream of cytokine receptors, which are implicated in the pathology of autoimmune, allergic and inflammatory diseases. Development of targeted small-molecule therapies such as JAK inhibitors, which have varied selective inhibitory profiles, has enabled a paradigm shift in the treatment of diverse disorders. JAK inhibitors suppress intracellular signalling mediated by multiple cytokines involved in the pathological processes of rheumatoid arthritis and many other immune and inflammatory diseases, and therefore have the capacity to target multiple aspects of those diseases. In addition to rheumatoid arthritis, JAK inhibition has potential for treatment of autoimmune diseases including systemic lupus erythematosus, spondyloarthritis, inflammatory bowel disease and alopecia areata, in which stimulation of innate immunity activates adaptive immunity, leading to generation of autoreactive T cells and activation and differentiation of B cells. JAK inhibitors are also effective in the treatment of allergic disorders, such as atopic dermatitis, and can even be used for the COVID-19-related cytokine storm. Mechanism-based treatments targeting JAK-STAT pathways have the potential to provide positive outcomes by minimizing the use of glucocorticoids and/or non-specific immunosuppressants in the treatment of systemic immune-mediated inflammatory diseases.
Topics: COVID-19; Humans; Janus Kinases; Rheumatology; SARS-CoV-2; STAT Transcription Factors
PubMed: 34987201
DOI: 10.1038/s41584-021-00726-8 -
Cells Apr 2021Myelofibrosis is a myeloproliferative neoplasm characterized by splenomegaly, constitutional symptoms, bone marrow fibrosis, and a propensity towards transformation to... (Review)
Review
Myelofibrosis is a myeloproliferative neoplasm characterized by splenomegaly, constitutional symptoms, bone marrow fibrosis, and a propensity towards transformation to acute leukemia. JAK inhibitors are the only approved therapy for myelofibrosis and have been successful in reducing spleen and symptom burden. However, they do not significantly impact disease progression and many patients are ineligible due to coexisting cytopenias. Patients who are refractory to JAK inhibition also have a dismal survival. Therefore, non-JAK inhibitor-based therapies are being explored in pre-clinical and clinical settings. In this review, we discuss novel treatments in development for myelofibrosis with targets outside of the JAK-STAT pathway. We focus on the mechanism, preclinical rationale, and available clinical efficacy and safety information of relevant agents including those that target apoptosis (navitoclax, KRT-232, LCL-161, imetelstat), epigenetic modulation (CPI-0610, bomedemstat), the bone marrow microenvironment (PRM-151, AVID-200, alisertib), signal transduction pathways (parsaclisib), and miscellaneous agents (tagraxofusp. luspatercept). We also provide commentary on the future of therapeutic development in myelofibrosis.
Topics: Apoptosis; Epigenesis, Genetic; Humans; Janus Kinases; Primary Myelofibrosis; Protein Kinase Inhibitors; Signal Transduction
PubMed: 33925695
DOI: 10.3390/cells10051034 -
Annals of the Rheumatic Diseases Jul 2021Janus kinase inhibitors (JAKinibs) are efficacious in rheumatoid arthritis (RA) with variable reported rates of adverse events, potentially related to differential JAK...
OBJECTIVE
Janus kinase inhibitors (JAKinibs) are efficacious in rheumatoid arthritis (RA) with variable reported rates of adverse events, potentially related to differential JAK family member selectivity. Filgotinib was compared with baricitinib, tofacitinib and upadacitinib to elucidate the pharmacological basis underlying its clinical efficacy and safety.
METHODS
In vitro JAKinib inhibition of signal transducer and activator of transcription phosphorylation (pSTAT) was measured by flow cytometry in peripheral blood mononuclear cells and whole blood from healthy donors and patients with RA following cytokine stimulation of distinct JAK/STAT pathways. The average daily pSTAT and time above 50% inhibition were calculated at clinical plasma drug exposures in immune cells. The translation of these measures was evaluated in ex vivo-stimulated assays in phase 1 healthy volunteers.
RESULTS
JAKinib potencies depended on cytokine stimulus, pSTAT readout and cell type. JAK1-dependent pathways (interferon (IFN)α/pSTAT5, interleukin (IL)-6/pSTAT1) were among the most potently inhibited by all JAKinibs in healthy and RA blood, with filgotinib exhibiting the greatest selectivity for JAK1 pathways. Filgotinib (200 mg once daily) had calculated average daily target inhibition for IFNα/pSTAT5 and IL-6/pSTAT1 that was equivalent to tofacitinib (5 mg two times per day), upadacitinib (15 mg once daily) and baricitinib (4 mg once daily), with the least average daily inhibition for the JAK2-dependent and JAK3-dependent pathways including IL-2, IL-15, IL-4 (JAK1/JAK3), IFNγ (JAK1/JAK2), granulocyte colony stimulating factor, IL-12, IL-23 (JAK2/tyrosine kinase 2) and granulocyte-macrophage colony-stimulating factor (JAK2/JAK2). Ex vivo pharmacodynamic data from phase 1 healthy volunteers clinically confirmed JAK1 selectivity of filgotinib.
CONCLUSION
Filgotinib inhibited JAK1-mediated signalling similarly to other JAKinibs, but with less inhibition of JAK2-dependent and JAK3-dependent pathways, providing a mechanistic rationale for its apparently differentiated efficacy:safety profile.
Topics: Antirheumatic Agents; Arthritis, Rheumatoid; Azetidines; Cells, Cultured; Cytokines; Heterocyclic Compounds, 3-Ring; Humans; Janus Kinase Inhibitors; Janus Kinases; Piperidines; Purines; Pyrazoles; Pyridines; Pyrimidines; Sulfonamides; Triazoles
PubMed: 33741556
DOI: 10.1136/annrheumdis-2020-219012