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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 -
Pharmacological Research Sep 2022The Janus kinase (JAK) family of nonreceptor protein-tyrosine kinases consists of JAK1, JAK2, JAK3, and TYK2 (Tyrosine Kinase 2). Each of these proteins contains a JAK... (Review)
Review
The Janus kinase (JAK) family of nonreceptor protein-tyrosine kinases consists of JAK1, JAK2, JAK3, and TYK2 (Tyrosine Kinase 2). Each of these proteins contains a JAK homology pseudokinase (JH2) domain that interacts with and regulates the activity of the adjacent protein kinase domain (JH1). The Janus kinase family is regulated by numerous cytokines including interferons, interleukins, and hormones such as erythropoietin and thrombopoietin. Ligand binding to cytokine receptors leads to the activation of associated Janus kinases, which then catalyze the phosphorylation of the receptors. The SH2 domain of signal transducers and activators of transcription (STAT) binds to the cytokine receptor phosphotyrosines thereby promoting STAT phosphorylation and activation by the Janus kinases. STAT dimers are then translocated into the nucleus where they participate in the regulation and expression of dozens of proteins. JAK1/3 signaling participates in the pathogenesis of inflammatory disorders while JAK1/2 signaling contributes to the development of myeloproliferative neoplasms as well as several malignancies including leukemias and lymphomas. An activating JAK2 V617F mutation occurs in 95% of people with polycythemia vera and about 50% of cases of myelofibrosis and essential thrombocythemia. Abrocitinib, ruxolitinib, and upadacitinib are JAK inhibitors that are FDA-approved for the treatment of atopic dermatitis. Baricitinib is used for the treatment of rheumatoid arthritis and covid 19. Tofacitinib and upadacitinib are JAK antagonists that are used for the treatment of rheumatoid arthritis and ulcerative colitis. Additionally, ruxolitinib is approved for the treatment of polycythemia vera while fedratinib, pacritinib, and ruxolitinib are approved for the treatment of myelofibrosis.
Topics: Arthritis, Rheumatoid; COVID-19; Humans; Janus Kinase 1; Janus Kinase 2; Janus Kinase Inhibitors; Janus Kinases; Polycythemia Vera; Primary Myelofibrosis; Protein Kinase Inhibitors
PubMed: 35878738
DOI: 10.1016/j.phrs.2022.106362 -
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 -
Dermatologic Therapy Jun 2022Morphea and systemic sclerosis (SSc) are rare disorders of connective tissue characterized by increased skin thickness and fibrosis, with current treatment options... (Review)
Review
Morphea and systemic sclerosis (SSc) are rare disorders of connective tissue characterized by increased skin thickness and fibrosis, with current treatment options having variable efficacies, many with limited therapeutic benefit. Janus kinase (JAK) inhibitors have been shown in preclinical studies to inhibit the fibrotic pathway in murine models of systemic sclerosis, by blocking TGF-beta mediated pathway of STAT protein activation. Additionally, case reports of the treatment of morphea and SSc with tofacitinib, a JAK 1/3 inhibitor, have shown improvement in skin sclerosis. Several JAK inhibitors have been developed and utilized in dermatologic and rheumatologic diseases. To date, tofacitinib has been by far the most commonly trialed JAK inhibitor in patients with SSc and morphea. Herein we review the preclinical studies reported in the literature supporting the use and efficacy of JAK inhibitors for the treatment of morphea and the cutaneous manifestations of SSc, as well as discuss the clinical cases published to date illustrating the benefits of JAK inhibitors in disease management. The pathogenesis and mechanism of action will be reviewed as it relates to the process of skin fibrosis in morphea and SSc, along with the murine models illustrating efficacy of JAK inhibitors in fibrotic disease. Based on available preclinical and clinical data as well as consideration of the mechanism of action of JAK inhibitors on the pathway for cutaneous fibrosis, there is promising evidence to support the use and further study of JAK inhibitors in the management of morphea and cutaneous fibrosis in SSc.
Topics: Animals; Fibrosis; Humans; Janus Kinase Inhibitors; Janus Kinases; Mice; Scleroderma, Localized; Scleroderma, Systemic; Transforming Growth Factor beta
PubMed: 35278019
DOI: 10.1111/dth.15437 -
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 -
Oncology 2020Interleukin-6 (IL-6) is a member of the pro-inflammatory cytokine family, induces the expression of a variety of proteins responsible for acute inflammation, and plays... (Review)
Review
Interleukin-6 (IL-6) is a member of the pro-inflammatory cytokine family, induces the expression of a variety of proteins responsible for acute inflammation, and plays an important role in the proliferation and differentiation of cells in humans. IL-6 signaling is mediated by building a complex of IL-6, the transmembrane IL-6 receptor (mIL-6R) or with soluble forms of IL-6R (sIL-6R), and the signal-transducing subunit molecule gp130. Therefore, three modes for IL-6 signaling may occur in which IL-6 is binding to mIL-6R (classic), to sIL-6R (trans-signaling), or is joined through IL-6R to gp130 on nearby located cells (trans-presentation). These pathways, and the fact that gp130 is ubiquitously expressed, lead to the pleiotropic functions of IL-6. The control of IL-6 signaling is regulated through the induction of suppressor molecules after activation of the IL-6 pathways as well as through the presence of sIL-6R and gp130 forms in the blood. Vice versa, an overproduction of IL-6 and dysregulation of the IL-6 signaling pathways can result in inflammatory and autoimmune disorders as well as cancer development suggesting that IL-6 plays a significant role in the human cytokine network. Several therapeutic agents have been evaluated for inhibiting the cytokine itself, the signaling via the IL-6 receptor, or target kinases (e.g., JAK/STAT) associated with the signaling pathways. Amongst others, tocilizumab (anti-IL-6R humanized antibody) has been approved for the treatment of rheumatoid arthritis, cytokine release syndrome, and idiopathic multicentric Castleman's disease (iMCD), whereas siltuximab (an IL-6 antagonist) received approval for iMCD only. Although not all IL-6-associated diseases respond to IL-6 blockade, a better understanding of the underlying mechanisms of the IL-6 pathways may, therefore, help to find the best treatment for IL-6-associated diseases in the near future.
Topics: Anti-Inflammatory Agents; Humans; Inflammation; Inflammation Mediators; Interleukin-6; Janus Kinase Inhibitors; Janus Kinases; Molecular Targeted Therapy; Receptors, Interleukin-6; STAT Transcription Factors; Signal Transduction
PubMed: 31958792
DOI: 10.1159/000505099 -
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