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1
Jones, Dan, Justin Windham, Brian Stewart, Luis Fayad, Alma Rodriguez, and Fredrick B. Hagemeister. "Differential JAK-STAT Pathway Activation in Primary Mediastinal Large B-Cell Lymphoma: Two Subgroups with Differential Cytokine Activation Patterns and Predicted Responses to Kinase Inhibitors." Blood 114, no. 22 (November 20, 2009): 968. http://dx.doi.org/10.1182/blood.v114.22.968.968.
Анотація:
Abstract Abstract 968 Background: Primary mediastinal large B-cell lymphoma (PMBCL) is a specialized type of diffuse large B-cell lymphoma which shows diagnostic and pathogenetic overlap with mediastinal classical Hodgkin lymphoma. Approximately 60% of patients with PMBCL have good response to conventional chemoradiotherapy with the rest often showing distant relapses. Microarray studies of PMBCL have revealed overexpression of components and targets of the JAK-STAT signaling pathways including upregulation of IL13 receptor and STAT1; a subset of PMBCL have genome amplification of JAK2 or deletion of the JAK suppressor SOCS1. Given this complexity, we examined the most common mechanism and effects of JAK-STAT dysregulation in a series of newly diagnosed and recurrent PMBCL. Methods: Fifty-three biopsies from 23 patients with PMBCL were assessed and correlated with outcome. JAK2 and SOCS1 copy number status were determined by quantitative PCR on genomic DNA. JAK-STAT pathway activation was probed using reverse transcription quantitative (RQ)-PCR for JAK2, JAK3, and a panel of IL-4 and IL-13 transcriptional targets. JAK-STAT activation was assessed in tissue arrays using antisera against phospho-activation epitopes of STAT1, STAT3, STAT5, and STAT6 using immunohistochemistry (IHC). Activation patterns were modeled in the PMBCL cell line Karpas (K)1106P at baseline and following IL-4 and IL-13 stimulation with or without a range of small molecule inhibitors and blocking antibodies. Growth parameters were measured by MTT and protein levels by flow cytometry, Western blot, RQ-PCR and kinase profiling. Results: JAK2 genomic amplification was present in 40% of PMBCL and SOCS1 deletion in 10% as well as in the K1106P line. By phospho-activation IHC, tumors in 20/23 (87%) patients showed STAT activation, mostly due to STAT1 (60.8%) followed by STAT3 (26.1%), with 6 cases showing mixed patterns. In different tumors, localized and uniform STAT activation patterns were seen. Constitutive STAT activation was correlated with high expression of IL-4 transcription targets including CCL17 and IL13RA as well as JAK2 autophosphorylation and inferior outcome (p = .007). Tumors with more localized foci of activation were associated with alternate transcription patterns. In the K1106P cell line, IL-4 but not IL-13 treatment led to inducible STAT1 activation whereas baseline STAT3/6 activation was highly regulated by cytokine exposure. The JAK2 inhibitor JSI124 blocked IL-4 induced STAT1 activation whereas the JAK inhibitors AG-490, NSC7908 and WHI-P154 did not but did block IL-4/IL-13-induced STAT3 activation. The JAK3 inhibitor ZM39923 was most effective in blocking cell growth but did not block STAT1 activation. Conclusions: JAK2-STAT pathway activation characterizes nearly all cases of PMBCL but genetic mechanisms are distinct leading to distinct patterns of STAT1 activation (driven predominantly through the type I IL-4 receptor) and STAT3/6 activation (driven predominantly through the type II IL13RA/IL4RA) with differential effects on growth parameters and gene regulation. The patterns of STAT activation and target gene expression in primary tumors comprising these two groups mirrored the response to small molecule inhibitors following cytokine exposure in vitro in the K1106P line and highlights differences between IL-4 and IL-13 signaling in PMBCL. Profiling of PMBCL biopsies with phosphoactivation IHC for STAT isoforms may be useful to subcategorize cases and select the optimal JAK-STAT pathway inhibitors for adjuvant therapy. Disclosures: No relevant conflicts of interest to declare.
2
Malemud, Charles J. "The role of the JAK/STAT signal pathway in rheumatoid arthritis." Therapeutic Advances in Musculoskeletal Disease 10, no. 5-6 (May 19, 2018): 117–27. http://dx.doi.org/10.1177/1759720x18776224.
Анотація:
Proinflammatory cytokine activation of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signal transduction pathway is a critical event in the pathogenesis and progression of rheumatoid arthritis. Under normal conditions, JAK/STAT signaling reflects the influence of negative regulators of JAK/STAT, exemplified by the suppressor of cytokine signaling and protein inhibitor of activated STAT. However, in rheumatoid arthritis (RA) both of these regulators are dysfunctional. Thus, continuous activation of JAK/STAT signaling in RA synovial joints results in the elevated level of matrix metalloproteinase gene expression, increased frequency of apoptotic chondrocytes and most prominently ‘apoptosis resistance’ in the inflamed synovial tissue. Tofacitinib, a JAK small molecule inhibitor, with selectivity for JAK2/JAK3 was approved by the United States Food and Drug Administration (US FDA) for the therapy of RA. Importantly, tofacitinib has demonstrated significant clinical efficacy for RA in the post-US FDA-approval surveillance period. Of note, the success of tofacitinib has spurred the development of JAK1, JAK2 and other JAK3-selective small molecule inhibitors, some of which have also entered the clinical setting, whereas other JAK inhibitors are currently being evaluated in RA clinical trials.
3
Cacciapaglia, F., V. Venerito, S. del Vescovo, S. Stano, R. Bizzoca, D. Natuzzi, N. Lacarpia, M. Fornaro, and F. Iannone. "AB0070 INHIBITION OF STAT3 IN PBMCs FROM RHEUMATOID ARTHRITIS PATIENTS: CLUES TO UNDERSTAND SELECTIVITY OF JANUS KINASE INHIBITORS." Annals of the Rheumatic Diseases 81, Suppl 1 (May 23, 2022): 1167.2–1168. http://dx.doi.org/10.1136/annrheumdis-2022-eular.1997.
Анотація:
BackgroundThe Janus kinase (Jak) - signal transducer and activator of transcription (STAT) pathway has 4 Jak proteins and 7 STAT factors that mediate intracellular downstream of cytokine receptors. Targeted small-molecule therapies with different bond affinity to Jak proteins have been demonstrated effective in rheumatoid arthritis (RA) treatment, but the clinical significance of selective inhibition remains unclear.ObjectivesTo explore the effect of selective inhibition of Jak-STAT pathway in peripheral blood mononuclear cells (PBMC) from RA patients compared to healthy donors (HD).MethodsIn vitro Jak inhibition of the subunit 3 of phosphorylated (p) than activated STAT was measured by flow cytometry in peripheral blood mononuclear cells (PBMC) from RA patients with active disease (DAS28>5.1) naïve to any DMARDs (n.5) and HD (n.5), following recombinant human 0.1 ng/ml IL-6 (Peprotech – NJ, USA) stimulation. After blood separation, PBMC were overnight incubated with IC50 concentrations of selective Jak1-, Jak2-, Jak3- and Tyk2-inhibitors (Biovision Inc. – CA, USA) with or without IL-6 stimulation. Mean fold-increase of pSTAT3 was then compared in presence of different compounds stimulation.ResultsMean pSTAT3 activity after overnight incubation was significantly higher in RA patients compared to HD (37%; 95CI 8.2-56.7 vs 17.9%; 95CI 4.6-21 – p=0.01). After IL-6 stimulation, a 2-fold and a 1.4-fold increase in pSTAT3 levels was observed in PBMC from RA patients and HD, respectively. In unstimulated PBMC from HD Jak-inhibitors didn’t significantly reduced pSTAT3 activity. In CD14+ cells from RA patients, pSTAT3 activity was reduced with no differences between all four selective Jak-inhibitors, while in CD4+ cells only Jak1-inhibition was able to reduce by 40% pSTAT3 activity. After IL-6 stimulation, the co-culture with Jak1- or JaK3- selective inhibitors was able to significantly reduce pSTAT3 levels in CD4+ lymphocytes, by an average of 20%. While in CD14+ monocytes Jak1-, Jak2- and Jak3- selective inhibitors were able to reduce pSTAT3 activity by a mean of 30%. Tyk-2 selective inhibitor did not interfere with STAT3 activation by IL-6 stimulation of PBMC from RA patients and HD.ConclusionJak/STAT3 activity of PBMC from RA patients with active disease may be differently modulated by specific inhibitors. Selectivity of Jak-inhibitors seems more relevant in lymphocytes after IL-6 stimulation. These preliminary findings may explain discrepancies in effectiveness of selective Jak-inhibitors and pave the way for different choices in clinical practice.References[1]Tanaka Y, et al. Nat Rev Rheumatol. 2022 Jan 5:1–13.[2]Traves PG, et al. Ann Rheum Dis. 2021 Jul;80(7):865-875.[3]Choy EH. Rheumatology (Oxford). 2019 Jun 1;58(6):953-962.Disclosure of InterestsNone declared
4
Cacciapaglia, F., S. Perniola, S. del Vescovo, S. Stano, R. Bizzoca, D. Natuzzi, M. Fornaro, and F. Iannone. "AB0134 IN-VITRO STUDY ON THE EFFECT OF SELECTIVE Jak-INHIBITORS ON PBMCs STAT3 PHOSPHORYLATION FROM SYSTEMIC SCLEROSIS PATIENTS." Annals of the Rheumatic Diseases 81, Suppl 1 (May 23, 2022): 1196.3–1197. http://dx.doi.org/10.1136/annrheumdis-2022-eular.2625.
Анотація:
BackgroundSystemic sclerosis (SSc) is a rare autoimmune connective tissue disease characterized by autoimmunity-driven damage and vasculopathy leading to fibrosis of the skin and internal organs (1). The Janus kinase (Jak) - signal transducer and activator of transcription (STAT) pathway has been evidenced markedly activated in SSc patients (2, 3), and its inhibition has been proved in preclinical and clinical trials (4), but no data on Jak selective inhibition are available.ObjectivesTo explore the effect of selective inhibition of Jak/STAT pathway in peripheral blood mononuclear cells (PBMC) from SSc patients.MethodsIn vitro Jak inhibition of the subunit 3 of phosphorylated (p) than activated STAT was measured by flow cytometry in peripheral blood mononuclear cells (PBMC) from SSc patients naïve to any immunosuppressive and/or corticosteroids (n.5). pSTAT3 activity was also assessed after stimulation with recombinant human 0.1 ng/ml IL-6 (Peprotech – NJ, USA). The PBMC were overnight incubated with IC50 concentrations of selective Jak1-, Jak2-, Jak3- and Tyk2-inhibitors (Biovision Inc. – CA, USA). Percentages of pSTAT3 positive cells were compared in presence of different compounds stimulation.ResultsAfter overnight incubation, percentage of pSTAT3 positive cells was significantly higher in CD14pos compared to CD4pos (16.3%; 95CI 10-22 vs 10.7%; 95CI 4--18, – p=0.02). pSTAT3posCD14pos cells were halved only by selective Jak3-inhibitor, while pSTAT3posCD4pos cells were reduced by 36% by selective Jak1-inhibitor. Selective Jak2- or Tyk2-inhibitors did not interfere with STAT3 phosphorylation in PBMC from SSc patients. After IL-6 stimulation, we observed a 2- and a 1.5-fold increase in percentage of pSTAT3posCD4pos and pSTAT3posCD14pos cells, respectively. pSTAT3posCD14pos cells were reduced in the PBMC co-culture with IL-6 and Jak-selective inhibitors, in contrast no effects were found in CD4pos cells. Specifically, selective Jak1- and Jak3-inhibitors reduced pSTAT3posCD14pos cells by an average of 37% and 25%, respectively. No effects were observed after co-culture with IL-6 and selective Jak2- or Tyk2-inhibitors.ConclusionJak/STAT3 pathway of PBMC from SSc patients with active disease may be differently modulated by specific inhibitors. Selectivity of Jak1- and Jak3-inhibitors seems more relevant, especially in CD14pos monocytes after IL-6 stimulation. These preliminary findings highlight some evidence for effectiveness of selective Jak-inhibitors in SSc treatment.References[1]Benfaremo D, et al. Systemic Sclerosis: From Pathophysiology to Novel Therapeutic Approaches. Biomedicines. 2022;10(1):163.[2]Talotta R. The rationale for targeting the JAK/STAT pathway in scleroderma-associated interstitial lung disease. Immunotherapy. 2021;13(3):241-256.[3]Cacciapaglia F, et al. Phosphorylated signal transducer and activator of transcription 3 (pSTAT3) is highly expressed in CD14+ circulating cells of scleroderma patients. Rheumatology (Oxford). 2020;59(6):1442-1444.[4]Karalilova RV, et al. Tofacitinib in the treatment of skin and musculoskeletal involvement in patients with systemic sclerosis, evaluated by ultrasound. Rheumatol Int. 2021;41(10):1743-1753.Disclosure of InterestsNone declared
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Conzelmann, Michael, Elena Rodionova, Michael Hess, Thomas Giese, Anthony D. Ho, Peter Dreger, and Thomas Luft. "Complementary JAK/STAT Signalling Is Required for the Pro-Inflammatory Effects of CD40 Ligation: Differential Effects in Human Myeloid and B Cells." Blood 110, no. 11 (November 16, 2007): 2413. http://dx.doi.org/10.1182/blood.v110.11.2413.2413.
Анотація:
Abstract CD40L represents a strong endogenous danger signal that induces pro-inflammatory activation of CD40-expressing cells such as dendritic cells (DC), monocytes, and B cells. However, since CD40 activation alone is insufficient to induce pro-inflammatory cytokines such as IL-12p70, we studied whether CD40-mediated pro-inflammatory activity might be dependent on co-signalling pathways involving JAK/STAT. Using quantitative Western blotting, we demonstrate that JAK/STAT signalling is induced by cytokines such as IL-4, GM-CSF and IFNg, whereas CD40 activation mediates NFkB signalling. CD40L-induced IL-12p70 and IL-10 secretion in human DC, monocytes, B cells, and chronic lymphocytic leukemia (CLL) cells was measured upon complementary JAK/STAT activation by IL-4, GM-CSF and IFNg in the presence and absence of specific inhibitors of JAK2, JAK3, and pan-JAK. Whereas IL-12p70 could not be induced by CD40 ligation or by cytokines alone, IL-12p70 secretion and suppression of IL-10 was reproducibly observed after co-stimulation of CD40L with IL-4, GM-CSF, or IFNg. This effect could be completely reversed by pan-JAK inhibition. Persistence of IL-4/GM-CSF/IFNg-mediated JAK/STAT signalling as late as 12 hours following cellular activation via CD40 was required for IL-12p70 secretion as shown by the effects of delayed JAK inhibition. Similarly, persistence between 12 and 24 hours of IL-12p35 and p40 mRNA expression correlated best with the level of IL-12p70 secretion. Specific inhibition of JAK2 and JAK3 further revealed a context-dependent action of the distinct JAK family members: JAK2 showed a strong co-dominant effect in the setting of IL-4-induced JAK/STAT activity. Both, JAK2 and JAK3 were required for IL-12p70 secretion, whereas JAK2 alone was sufficient to modulate IL-10 secretion. However, in the context of IFNg-induced JAK/STAT signalling in DC, neither JAK2 nor JAK3 inhibition had effects on IL-12p70. Here, only inhibition by the pan-JAK inhibitor involving JAK1 abrogated IL-12p70 secretion, indicating that in IFNg-dependent signalling, JAK2 is apparently sub-dominant to JAK1 and had only a small enhancing effect on IL-10. This context dependence markedly differed in myeloid cells and B cells, as normal and malignant (CLL) B cells maintain a co-dominant JAK2 activity in the context of IFNg-induced JAK/STAT-signalling. In conclusion, complementary JAK/STAT signalling is required for the pro-inflammatory effects of CD40 ligation in humans, with different JAK subset predominance in myeloid and B cells. These results may open new ways of lineage-specific interfering with CD40 signals by modulating JAK/STAT activity using tyrosine kinase inhibitors.
6
Galli Sanchez, Ana Paula, Tatiane Ester Aidar Fernandes, and Gustavo Martelli Palomino. "The JAK-STAT Pathway and the JAK Inhibitors." Journal of Clinical Research in Dermatology 7, no. 5 (November 30, 2020): 1–6. http://dx.doi.org/10.15226/2378-1726/7/5/001128.
Анотація:
Dozens of cytokines that bind Type I and Type II receptors use the Janus Kinases (JAK) and the Signal Transducer and Activator of Transcription (STAT) proteins pathway for intracellular signaling, orchestrating hematopoiesis, inducing inflammation, and controlling the immune response. Currently, oral JAK inhibitors are being used to treat many inflammatory and myeloproliferative diseases and are also under investigation in several clinical trials for skin diseases. Thus, dermatologists should understand how the JAK-STAT pathway works as well as the mechanism of action of the JAK inhibitors which will certainly become an important part of the dermatologist’s treatment armamentarium in the next few years. Keywords: JAK inhibitors; Janus Kinases; JAK-STAT Pathway List of Abbreviations: AD: Atopic Dermatitis ADP: Adenosine diphosphate Dmards: Disease-Modifying Antirheumatic Drugs JAK: Janus kinase(s) Jaki: Janus kinase Inhibitor(s) PIAS: Protein Inhibitor of Activated STAT P-STAT: Phosphorylated STAT STAT: Signal Transducer and Activator of Transcription TYK2: Tyrosine Kinase 2 Wsxws: Tryptophan-Serine-X-Tryptophan-Serine
7
Raivola, Juuli, Teemu Haikarainen, Bobin George Abraham, and Olli Silvennoinen. "Janus Kinases in Leukemia." Cancers 13, no. 4 (February 14, 2021): 800. http://dx.doi.org/10.3390/cancers13040800.
Анотація:
Janus kinases (JAKs) transduce signals from dozens of extracellular cytokines and function as critical regulators of cell growth, differentiation, gene expression, and immune responses. Deregulation of JAK/STAT signaling is a central component in several human diseases including various types of leukemia and other malignancies and autoimmune diseases. Different types of leukemia harbor genomic aberrations in all four JAKs (JAK1, JAK2, JAK3, and TYK2), most of which are activating somatic mutations and less frequently translocations resulting in constitutively active JAK fusion proteins. JAKs have become important therapeutic targets and currently, six JAK inhibitors have been approved by the FDA for the treatment of both autoimmune diseases and hematological malignancies. However, the efficacy of the current drugs is not optimal and the full potential of JAK modulators in leukemia is yet to be harnessed. This review discusses the deregulation of JAK-STAT signaling that underlie the pathogenesis of leukemia, i.e., mutations and other mechanisms causing hyperactive cytokine signaling, as well as JAK inhibitors used in clinic and under clinical development.
8
Raivola, Juuli, Teemu Haikarainen, and Olli Silvennoinen. "Characterization of JAK1 Pseudokinase Domain in Cytokine Signaling." Cancers 12, no. 1 (December 27, 2019): 78. http://dx.doi.org/10.3390/cancers12010078.
Анотація:
The Janus kinase-signal transducer and activator of transcription protein (JAK-STAT) pathway mediates essential biological functions from immune responses to haematopoiesis. Deregulated JAK-STAT signaling causes myeloproliferative neoplasms, leukaemia, and lymphomas, as well as autoimmune diseases. Thereby JAKs have gained significant relevance as therapeutic targets. However, there is still a clinical need for better JAK inhibitors and novel strategies targeting regions outside the conserved kinase domain have gained interest. In-depth knowledge about the molecular details of JAK activation is required. For example, whether the function and regulation between receptors is conserved remains an open question. We used JAK-deficient cell-lines and structure-based mutagenesis to study the function of JAK1 and its pseudokinase domain (JH2) in cytokine signaling pathways that employ JAK1 with different JAK heterodimerization partner. In interleukin-2 (IL-2)-induced STAT5 activation JAK1 was dominant over JAK3 but in interferon-γ (IFNγ) and interferon-α (IFNα) signaling both JAK1 and heteromeric partner JAK2 or TYK2 were both indispensable for STAT1 activation. Moreover, IL-2 signaling was strictly dependent on both JAK1 JH1 and JH2 but in IFNγ signaling JAK1 JH2 rather than kinase activity was required for STAT1 activation. To investigate the regulatory function, we focused on two allosteric regions in JAK1 JH2, the ATP-binding pocket and the αC-helix. Mutating L633 at the αC reduced basal and cytokine induced activation of STAT in both JAK1 wild-type (WT) and constitutively activated mutant backgrounds. Moreover, biochemical characterization and comparison of JH2s let us depict differences in the JH2 ATP-binding and strengthen the hypothesis that de-stabilization of the domain disturbs the regulatory JH1-JH2 interaction. Collectively, our results bring mechanistic understanding about the function of JAK1 in different receptor complexes that likely have relevance for the design of specific JAK modulators.
9
Bhagwat, Neha, Priya Koppikar, Outi Kilpivaara, Taghi Manshouri, Mazhar Adli, Ann Mullally, Omar Abdel-Wahab, et al. "Heterodimeric JAK-STAT Activation As a Mechanism of Persistence to JAK2 Inhibitor Therapy." Blood 118, no. 21 (November 18, 2011): 122. http://dx.doi.org/10.1182/blood.v118.21.122.122.
Анотація:
Abstract Abstract 122 Although JAK2 inhibitor therapy improves MPN-associated splenomegaly and systemic symptoms, JAK2 inhibitor treatment does not significantly reduce or eliminate the MPN clone in most MPN patients. We therefore sought to characterize mechanisms by which MPN cells can persist despite chronic JAK2 inhibition. We performed saturation mutagenesis followed by next-generation sequencing in JAK2 mutant cells exposed to two different JAK2 inhibitors, INCB18424, a dual JAK1/JAK2 inhibitor, and JAK Inhibitor I, a pan-JAK inhibitor. Although we were able to identify candidate resistance alleles, these alleles were present in less than 50% of the total population. These data and the clinical experience with JAK2 inhibitors suggest that the failure of JAK2 inhibitors to reduce disease burden is not due to acquired drug resistance but rather due to persistent growth and signaling in the setting of chronic JAK2 kinase inhibition. We therefore generated JAK2/MPL mutant JAK2-inhibitor persistent (JAKper) cell lines (SET-2, UKE-1, Ba/F3-MPLW515L). JAKper cell lines are able to survive and proliferate in the presence of JAK2 inhibitors including JAK Inhibitor I, INCB18424 and TG101348 without acquiring second-site resistance alleles and are also insensitive to other JAK inhibitors. Signaling studies revealed JAK-STAT signaling was reactivated in persistent cells at concentrations of inhibitor that completely abrogated signaling in naïve cells, and JAK2 phosphorylation was reactivated in JAK inhibitor persistent cells consistent with reactivation of the JAK-STAT pathway in JAKper cells despite inhibitor exposure. We hypothesized that JAK2 may be activated in trans by other JAK kinases, and found an increased association between activated JAK2 and JAK1/TYK2 consistent with activation of JAK2 in trans by other JAK kinases in JAKper cells. We next assessed whether JAK inhibitor persistence was reversible. Withdrawal of JAK2 inhibitors from JAKper cells for 2 weeks led to resensitization such that JAKper resensitized cells were now sensitive to different JAK2 inhibitors regardless of previous exposure. Resensitization was associated with reversal of heterodimerization and loss of transactivation of JAK2 by JAK1 and TYK2. The reversible nature of JAK inhibitor persistence led us to hypothesize epigenetic alterations are responsible for JAK inhibitor insensitivity in JAKper cells; we observed increased expression of JAK2 at the mRNA and protein level in JAK2 inhibitor persistent cells compared to parental as well as resensitized cells. ChIP-PCR analysis of the JAK2 locus revealed a significant increase in H3K4-trimethylation and a reduction in H3K9 trimethylation in persistent cells compared to parental cells consistent with a change to a more active chromatin state at the JAK2 locus and increased JAK2 mRNA expression in persistent cells. We next assessed whether the same phenomenon of JAK2 inhibitor persistence was observed in vivo. In a MPLW515L-mutant murine bone marrow transplant model of primary myelofibrosis, we observed increased JAK2 expression, increased JAK2 phosphorylation and JAK-inhibitor induced association between JAK1 and JAK2 in hematopoietic cells from INCB18424 treated mice. We next extended our findings to samples from patients treated with INCB18424. We identified 5 patients who had a significant clinical response and 5 patients without a significant clinical response as assessed by spleen size and JAK2V617F allele burden responses and measured JAK2 granulocyte mRNA expression before and during INCB18424 treatment. We found that JAK2 mRNA levels significantly increased in INCB18424 nonresponders compared to responders (p=0.05) suggesting this phenomenon is observed in cell lines, mouse models and primary samples. Finally, we investigated whether JAKper cells remain JAK2 dependent. Studies with shRNA targeting JAK2 and pharmacologic studies using Hsp90 inhibitors that degrade JAK2 protein demonstrate that JAK2 inhibitor persistent cells remain dependent on JAK2 protein expression. Our data indicate that JAK2/MPL mutant cells persist in the presence of JAK2 kinase inhibitors through epigenetic alterations which reactivate signaling in persistent cells, and that therapies which lead to JAK2 degradation can be used to inhibit signaling and improve outcomes in patients with persistent disease despite chronic JAK2 inhibition. Disclosures: Verstovsek: Incyte Corporation: Research Funding.
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Meyer, Sara C., Matthew D. Keller, Priya Koppikar, Olga A. Guryanova, Maria Kleppe, Anna Sophia McKenney, William R. Sellers, et al. "Type II Inhibition of JAK2 with NVP-CHZ868 Reverses Type I JAK Inhibitor Persistence and Demonstrates Increased Efficacy in MPN Models." Blood 124, no. 21 (December 6, 2014): 160. http://dx.doi.org/10.1182/blood.v124.21.160.160.
Анотація:
Abstract The identification of JAK2 mutations in patients with myeloproliferative neoplasms (MPN) led to the clinical development of JAK2 inhibitors, and the JAK1/2 inhibitor ruxolitinib has been approved for the treatment of myelofibrosis (MF). Although clinically tested JAK inhibitors improve MPN-associated splenomegaly and systemic symptoms, they do not significantly reduce the MPN clone in most MPN patients.We previously demonstrated that MPN cells can acquire persistence to ruxolitinib and other type I JAK inhibitors which bind the active conformation of JAK2, and that JAK2 inhibitor persistence is associated with reactivation of JAK-STAT signaling and with heterodimerization between activated JAK2 and JAK1/TYK2, consistent with activation of JAK2 in trans by other JAK kinases. We have now extended our studies to other type I JAK inhibitors in clinical development, including CYT387, BMS911543 and SAR302503. In each case we see the same mechanism of persistence as observed with ruxolitinib, with transactivation of JAK2 by other JAK kinases. Most importantly, we found that MPN cells which were persistent to one JAK inhibitor were insensitive to the other JAK inhibitors, suggesting that the mechanisms which limit overall efficacy of ruxolitinib will limit the efficacy of other JAK inhibitors in clinical development. All JAK inhibitors in clinical development are type I inhibitors that interact with and inhibit the active confirmation of the JAK2 kinase. We hypothesized that novel, type II JAK inhibitors that interact with and inhibit JAK2 in the inactive conformation might retain activity in JAK inhibitor persistent cells and show increased efficacy in murine MPN models. We therefore characterized the efficacy of NVP-CHZ868, a novel type II JAK inhibitor, in MPN cells and in murine MPN models. CHZ868 potently inhibited proliferation of cells expressing the JAK2V617F mutation or the TEL-JAK2 fusion. We found that JAK2/MPL-mutant cell lines were universally sensitive to NVP-CHZ868. CHZ868 treatment of JAK2-mutant SET2 cells induced a higher degree of apoptosis compared to ruxolitinib. Signaling studies demonstrated that CHZ868 more potently attenuated JAK-STAT signaling in JAK2/MPL-mutant cells, with suppression of JAK2 phosphorylation consistent with a type II mechanism of kinase inhibition. We next investigated the ability of CHZ868 to inhibit the proliferation and signaling of MPN cells that had acquired persistence to type I JAK inhibitors. Type II inhibition with CHZ868 completely suppressed JAK-STAT signaling in type I JAK inhibitor-persistent cells, and prevented heterodimeric activation of JAK2 by JAK1 and TYK2. Most importantly, JAK2/MPL-mutant cells which were insensitive to type I JAK inhibitors remained highly sensitive to CHZ868, demonstrating that type I JAK inhibitor persistence does not confer resistance to type II inhibitors. We next evaluated the efficacy of CHZ868 in murine models of JAK2/MPL-mutant MPN. CHZ868 showed significant activity in conditional knock-in and bone marrow transplant (BMT) models of Jak2V617F-induced polycythemia vera, with normalization of hematocrit, reversal of stem/progenitor expansion, normalization of splenomegaly/splenic architecture, and reversal of bone marrow fibrosis. CHZ868 demonstrated similar activity in the MPLW515L BMT model of MF, with normalization of blood counts, stem/progenitor expansion, spleen weights, and extramedullary hematopoiesis in vivo. Most importantly, CHZ868 resulted in significant reductions of mutant allele burden (mean allele burden reduction 49%) in the Jak2V617F model. We observed analogous reductions in allele burden in the Jak2V617F and MPLW515L BMT models, consistent with disease modifying activity. Taken together, our data demonstrate that a spectrum of type I JAK inhibitors induce JAK inhibitor persistence, by a similar mechanism of JAK2 transactivation as observed with ruxolitinib. By contrast, type II JAK inhibition with CHZ868 remains highly active in JAK inhibitor persistent cells, and shows increased activity in murine MPN models. These data demonstrate that novel JAK inhibitors can increase target inhibition and therapeutic efficacy and should be pursued as an approach to improve outcomes for MPN patients. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures Koppikar: Amgen: Employment. Sellers:Novartis: Employment. Hofmann:Novartis: Employment. Baffert:Novartis: Employment. Gaul:Novartis: Employment. Radimerski:Novartis: Employment. Levine:Novartis: Consultancy, Grant support Other.
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Gorre, M., I. Jilani, H. Kantarjian, F. Giles, A. Hannah, and M. Albitar. "Novel Quantitative Flow Cytometry-Based Signaling Assays Reveal a Potential Role for HSP90 Inhibitors in the Treatment of JAK2 Mutant-Positive Diseases." Blood 106, no. 11 (November 16, 2005): 3526. http://dx.doi.org/10.1182/blood.v106.11.3526.3526.
Анотація:
Abstract The V617F mutation in the JAK2 tyrosine kinase, recently described in a majority of patients with myeloproliferative disorders (MPDs), confers growth factor independence in vitro and oncogenicity in mice. Therefore, targeted inhibition of mutant JAK2 kinase activity may be an effective strategy for treatment of MPD patients with this mutation. The ability to measure the activation status of JAK2 in patient samples will thus be of substantial value for monitoring therapeutic efficacy. We have developed quantitative flow cytometry-based assays for rapid and reproducible measurement of intracellular total and phosphorylated proteins of the canonical JAK/STAT pathway, as well as heat shock proteins (HSPs). In this study we examined the ability of these assays to detect altered levels of total and phosphorylated JAK/STAT signaling pathway components and HSP in a cell line (HEL) that is homozygous for the V617F JAK2 mutant. HEL cell cultures were incubated with 17AAG, a geldanamycin analog with clinical utility in a broad range of diseases. 17AAG exerts its inhibitory effect by binding to heat shock protein 90 (HSP90), preventing its chaperone association with client oncoproteins. AKT is among these client proteins and a component of the JAK/STAT pathway, representing a potential therapeutic target. 17AAG exposure reduced total AKT protein levels by 42%. 17AAG also inhibited mutant JAK2 activity by 66% and had a smaller effect (17%) on total JAK2 levels, suggesting that mutant JAK2 activation may rely on HSP90, either directly or through dependence on other client proteins. Exposure to 17AAG also reduced levels of P-STAT5 (50%) and, to a lesser extent, total STAT5 (27%). 17AAG-treated cells showed a 55% reduction in HSP90 levels and a 14% increase in HSP70 protein levels. JAK Inhibitor I (Calbiochem), a potent pan-JAK Inhibitor that blocks JAK1, JAK2, and JAK3 activity, caused reductions in P-JAK2 and P-STAT5 levels (29% and 26% decreases, respectively). However, the combining of JAK Inhibitor I with 17AAG did not result in an enhanced effect beyond what was observed with 17AAG treatment alone. Similar results were seen with AG490, a potent and selective JAK2 inhibitor. 17AAG caused a 40% decrease in viable cells after 18 hrs of treatment, compared with a 35% reduction for the pan-JAK inhibitor and a 20% decrease for AG490. Combining 17AAG with the pan-JAK inhibitor or AG490 caused only minor enhancement of these cytotoxic effects (46% and 41% reduction in cell viability, respectively). Our data support the potential utility of HSP90 inhibitors such as 17AAG in the development of small-molecule therapy for mutant JAK2 kinase-positive MPD. These results also show that flow cytometry-based assays for JAK/STAT signaling components and HSPs can be used to quantitatively monitor drug efficacy at the protein level in intact cells. These tests are likely to have broad clinical utility given the spectrum of diseases in which a pathogenic role for mutant JAK2 kinase is implicated.
12
Callus, Bernard A., and Bernard Mathey-Prevot. "Interleukin-3–Induced Activation of the JAK/STAT Pathway Is Prolonged by Proteasome Inhibitors." Blood 91, no. 9 (May 1, 1998): 3182–92. http://dx.doi.org/10.1182/blood.v91.9.3182.
Анотація:
Abstract One facet of cytokine receptor signaling involves the activation of signal transducers and activators of transcription (STATs). STATs are rapidly activated via tyrosine phosphorylation by Janus kinase (JAK) family members and subsequently inactivated within a short period. We investigated the effect of proteasome inhibition on interleukin-3 (IL-3) activation of the JAK/STAT pathway following stimulation of Ba/F3 cells. Treatment of Ba/F3 cells with the proteasome inhibitor,N-acetyl-l-leucinyl-l-leucinyl-norleucinal (LLnL), led to stable tyrosine phosphorylation of the IL-3 receptor, beta common (βc), and STAT5 following stimulation. The effects of LLnL were not restricted to the JAK/STAT pathway, as Shc and mitogen-activated protein kinase (MAPK) phosphorylation were also prolonged in LLnL-treated cells. Further investigation showed these stable phosphorylation events were the result of prolonged activation of JAK2 and JAK1. These observations were confirmed using pharmacologic inhibitors. In the presence of LLnL, stable phosphorylation of STAT5 and βc was abrogated if the tyrosine kinase inhibitor, staurosporine, was added. The effect of staurosporine on STAT5 phosphorylation could be overcome if the phosphatase inhibitor, vanadate, was also added, suggesting phosphorylated STAT5 could be stabilized by phosphatase, but not by proteasome inhibition per se. These observations are consistent with the hypothesis that proteasome-mediated protein degradation can modulate the activity of the JAK/STAT pathway by regulating the deactivation of JAK.
13
Callus, Bernard A., and Bernard Mathey-Prevot. "Interleukin-3–Induced Activation of the JAK/STAT Pathway Is Prolonged by Proteasome Inhibitors." Blood 91, no. 9 (May 1, 1998): 3182–92. http://dx.doi.org/10.1182/blood.v91.9.3182.3182_3182_3192.
Анотація:
One facet of cytokine receptor signaling involves the activation of signal transducers and activators of transcription (STATs). STATs are rapidly activated via tyrosine phosphorylation by Janus kinase (JAK) family members and subsequently inactivated within a short period. We investigated the effect of proteasome inhibition on interleukin-3 (IL-3) activation of the JAK/STAT pathway following stimulation of Ba/F3 cells. Treatment of Ba/F3 cells with the proteasome inhibitor,N-acetyl-l-leucinyl-l-leucinyl-norleucinal (LLnL), led to stable tyrosine phosphorylation of the IL-3 receptor, beta common (βc), and STAT5 following stimulation. The effects of LLnL were not restricted to the JAK/STAT pathway, as Shc and mitogen-activated protein kinase (MAPK) phosphorylation were also prolonged in LLnL-treated cells. Further investigation showed these stable phosphorylation events were the result of prolonged activation of JAK2 and JAK1. These observations were confirmed using pharmacologic inhibitors. In the presence of LLnL, stable phosphorylation of STAT5 and βc was abrogated if the tyrosine kinase inhibitor, staurosporine, was added. The effect of staurosporine on STAT5 phosphorylation could be overcome if the phosphatase inhibitor, vanadate, was also added, suggesting phosphorylated STAT5 could be stabilized by phosphatase, but not by proteasome inhibition per se. These observations are consistent with the hypothesis that proteasome-mediated protein degradation can modulate the activity of the JAK/STAT pathway by regulating the deactivation of JAK.
14
Hashemi, David, and Neal Bhatia. "The JAK-Cytokine Interface – A Review and Update on Prospective Clinical Considerations." SKIN The Journal of Cutaneous Medicine 7, no. 4 (July 17, 2023): 932–35. http://dx.doi.org/10.25251/skin.7.4.16.
Анотація:
Janus kinases (JAKs) are non-receptor tyrosine kinases that work together with signal transducers and activators of transcription (STAT) proteins to form the JAK/STAT pathway. Together, this pathway is responsible for mediating a wide range of downstream cytokines and growth factors, and inhibition of various components of this pathway has been a major area of research focus in recent years. Each of the major enzymes of the family – which include JAK1, JAK2, JAK3, and Tyrosine Kinase 2 (TYK2) – or combinations of JAKs is responsible for its own set of most strongly-associated inflammatory mediators, and inhibition of specific JAKs or combination of JAKs can therefore also potentially allow for modulation of specific inflammatory factors and their associated conditions. To date, JAK inhibitors have particularly been studied in the treatment of atopic dermatitis (felt to be primarily driven by IL-4, IL-13, and IL-5), psoriasis (IL-12/IL-23), alopecia areata (IL-2, IL-15, and IFN-γ), and vitiligo (IL-15 and IFN-γ), given that these factors can all be found downstream of specific JAK/STAT pathways as shown in Figure 1. By providing a concise review of the inflammatory factors affected by each JAK, this article aims to support clinicians as they engage in the ever-growing body of research around the use of JAK inhibitors for potential treatment of dermatologic conditions.
15
Shawky, Ahmed M., Faisal A. Almalki, Ashraf N. Abdalla, Ahmed H. Abdelazeem, and Ahmed M. Gouda. "A Comprehensive Overview of Globally Approved JAK Inhibitors." Pharmaceutics 14, no. 5 (May 6, 2022): 1001. http://dx.doi.org/10.3390/pharmaceutics14051001.
Анотація:
Janus kinase (JAK) is a family of cytoplasmic non-receptor tyrosine kinases that includes four members, namely JAK1, JAK2, JAK3, and TYK2. The JAKs transduce cytokine signaling through the JAK-STAT pathway, which regulates the transcription of several genes involved in inflammatory, immune, and cancer conditions. Targeting the JAK family kinases with small-molecule inhibitors has proved to be effective in the treatment of different types of diseases. In the current review, eleven of the JAK inhibitors that received approval for clinical use have been discussed. These drugs are abrocitinib, baricitinib, delgocitinib, fedratinib, filgotinib, oclacitinib, pacritinib, peficitinib, ruxolitinib, tofacitinib, and upadacitinib. The aim of the current review was to provide an integrated overview of the chemical and pharmacological data of the globally approved JAK inhibitors. The synthetic routes of the eleven drugs were described. In addition, their inhibitory activities against different kinases and their pharmacological uses have also been explained. Moreover, their crystal structures with different kinases were summarized, with a primary focus on their binding modes and interactions. The proposed metabolic pathways and metabolites of these drugs were also illustrated. To sum up, the data in the current review could help in the design of new JAK inhibitors with potential therapeutic benefits in inflammatory and autoimmune diseases.
16
Musumeci, Francesca, Chiara Greco, Ilaria Giacchello, Anna Lucia Fallacara, Munjed M. Ibrahim, Giancarlo Grossi, Chiara Brullo, and Silvia Schenone. "An Update on JAK Inhibitors." Current Medicinal Chemistry 26, no. 10 (June 20, 2019): 1806–32. http://dx.doi.org/10.2174/0929867325666180327093502.
Анотація:
Janus kinases (JAKs) are a family of non-receptor tyrosine kinases, composed by four members, JAK1, JAK2, JAK3 and TYK2. JAKs are involved in different inflammatory and autoimmune diseases, as well as in malignancies, through the activation of the JAK/STAT signalling pathway. Furthermore, the V617F mutation in JAK2 was identified in patients affected by myeloproliferative neoplasms. This knowledge prompted researchers from academia and pharmaceutical companies to investigate this field in order to discover small molecule JAK inhibitors. These efforts recently afforded to the market approval of four JAK inhibitors. Despite the fact that all these drugs are pyrrolo[2,3-d]pyrimidine derivatives, many compounds endowed with different heterocyclic scaffolds have been reported in the literature as selective or multi-JAK inhibitors, and a number of them is currently being evaluated in clinical trials. In this review we will report many representative compounds that have been published in articles or patents in the last five years (period 2013-2017). The inhibitors will be classified on the basis of their chemical structure, focusing, when possible, on their structure activity relationships, selectivity and biological activity. For every class of derivatives, compounds disclosed before 2013 that have entered clinical trials will also be briefly reported, to underline the importance of a particular chemical scaffold in the search for new inhibitors.
17
Suzuki, Asuka, Toshikatsu Hanada, Keiichi Mitsuyama, Takafumi Yoshida, Shintaro Kamizono, Tomoaki Hoshino, Masato Kubo, et al. "Cis3/Socs3/Ssi3 Plays a Negative Regulatory Role in Stat3 Activation and Intestinal Inflammation." Journal of Experimental Medicine 193, no. 4 (February 12, 2001): 471–82. http://dx.doi.org/10.1084/jem.193.4.471.
Анотація:
Immune and inflammatory systems are controlled by multiple cytokines, including interleukins (ILs) and interferons. These cytokines exert their biological functions through Janus tyrosine kinases and signal transducer and activator of transcription (STAT) transcription factors. We recently identified two intrinsic Janus kinase (JAK) inhibitors, JAK binding protein (JAB; also referred to as suppressor of cytokine signaling [SOCS1]/STAT-induced STAT inhibitor [SSI1]) and cytokine-inducible SH2 protein (CIS)3 (or SOCS3/SSI3), which play an essential role in the negative regulation of cytokine signaling. We have investigated the role of STATs and these JAK inhibitors in intestinal inflammation. Among STAT family members, STAT3 was most strongly tyrosine phosphorylated in human ulcerative colitis and Crohn's disease patients as well as in dextran sulfate sodium (DSS)-induced colitis in mice. Development of colitis as well as STAT3 activation was significantly reduced in IL-6–deficient mice treated with DSS, suggesting that STAT3 plays an important role in the perpetuation of colitis. CIS3, but not JAB, was highly expressed in the colon of DSS-treated mice as well as several T cell–dependent colitis models. To define the physiological role of CIS3 induction in colitis, we developed a JAB mutant (F59D-JAB) that overcame the inhibitory effect of both JAB and CIS3 and created transgenic mice. DSS induced stronger STAT3 activation and more severe colitis in F59D-JAB transgenic mice than in their wild-type littermates. These data suggest that hyperactivation of STAT3 results in severe colitis and that CIS3 plays a negative regulatory role in intestinal inflammation by downregulating STAT3 activity.
18
Thomas, Sally J., Katherine Fisher, Stephen Brown, John A. Snowden, Sarah Danson, and Martin Zeidler. "Methotrexate Is a Suppressor of JAK/STAT Pathway Activation Which Inhibits JAK2V617F Induced Signalling." Blood 124, no. 21 (December 6, 2014): 4577. http://dx.doi.org/10.1182/blood.v124.21.4577.4577.
Анотація:
Abstract The classical myeloproliferative neoplasms (MPNs) are a group of disorders characterised by activation of the JAK/STAT signalling pathway. A large proportion of patients with MPNs have an acquired mutation, JAK2V617F, which causes constitutive kinase activity. Patients with wild-type JAK2 show gene expression patterns characteristic of JAK/STAT activation, and the majority have mutations in other genes associated with increased pathway activation. Inhibition of JAK/STAT activation represents an attractive therapeutic approach for these disorders. In myelofibrosis, treatment with a JAK inhibitor reduces spleen volume, improves quality of life and prolongs life expectancy, whereas there is evidence that other therapies are no better than placebo. This study aimed to find new treatments for MPNs by identifying compounds that suppress JAK/STAT activation. We screened a small-molecule library consisting of FDA approved drugs, cytotoxic drugs, agrochemicals, and pure natural products to identify modulators of STAT-responsive transcription in the low complexity Drosophila model. We independently identified methotrexate (z-score -8.72) and the chemically similar aminopterin (z-score -8.2) as strong inhibitors of Drosophila JAK/STAT activation. The suppression of transcriptional reporter activity was dose dependent and was observed following activation of the pathway with the Drosophila JAK/STAT ligand Upd and by the gain of function Drosophila JAK HopTuml. To examine whether these results translated to the more complex JAK/STAT signalling pathway of humans we examined the effect of methotrexate in the Hodgkin Lymphoma cell line HDLM-2, which shows constitutive phosphorylation of several JAK/STAT family members. Immunoblotting for phosphorylated pathway components showed that methotrexate produced a dose dependent reduction in levels of tyrosine phosphorylated STAT5 (Y694), without affecting total STAT5 levels. Methotrexate did not affect phosphorylated proteins in other signalling pathways, including pAKT, p c-Jun or pMAPK. To examine the potential of methotrexate as a treatment for MPNs, we used the HEL cell line, which is homozygous for JAK2V617F and shows STAT5 phosphorylation that is dependent on JAK2 activity. Immunoblotting showed that methotrexate produced a dose dependent reduction in levels of pSTAT5. Significant suppression of STAT5 phosphorylation was seen following treatment with methotrexate at concentrations equivalent to those measured in the serum of patients taking low dose oral methotrexate (0.4 – 0.8 mM, p<0.001, one-way ANOVA with Dunnett’s multiple comparisons test). Suppression of STAT5 phosphorylation persisted in the presence of folinic acid at concentrations used to prevent methotrexate toxicity, suggesting that the effect on JAK/STAT signalling is not mediated by impairment of folate metabolism. Methotrexate did not completely prevent signalling via the JAK/STAT pathway, as methotrexate-treated cells were still able to phosphorylate STAT5 following stimulation with the EpoR/JAK2/STAT5 pathway ligand erythropoietin. The reduction in STAT5 phosphorylation produced by treatment with methotrexate was comparable to that produced by the JAK1/JAK2 inhibitor ruxolitinib, although ruxolitinib was a more potent inhibitor of pathway activation. Given that methotrexate is used to treat inflammatory disorders and activation of JAK/STAT signalling is involved in the inflammatory response we examined the effect of methotrexate on rheumatoid arthritis fibroblast-like synoviocytes. Methotrexate also reduced constitutive STAT phosphorylation in these primary cells. Our results suggest that low-dose oral methotrexate should be investigated as a potential treatment for patients with MPNs. We suggest that methotrexate may suppress pathological over-activation of the JAK/STAT pathway sufficiently to control disease and bring about the benefits demonstrated with specific JAK inhibitors, without preventing physiological activation required for haematopoiesis and response to infection. Methotrexate is inexpensive and has advantages as a potential treatment as its safety and adverse effects are already well understood. Furthermore, our results suggest that suppression of JAK/STAT pathway activation may be a mechanism through which methotrexate exerts anti-inflammatory and immunosuppressive effects. Disclosures Off Label Use: Methotrexate is widely used as a chemotherapy drug and to treat inflammatory disorders. This work includes a discussion of the potential use of methotrexate to treat myeloproliferative neoplasms, based on experiments in cell lines.
19
Taldaev, Amir, Vladimir R. Rudnev, Kirill S. Nikolsky, Liudmila I. Kulikova, and Anna L. Kaysheva. "Molecular Modeling Insights into Upadacitinib Selectivity upon Binding to JAK Protein Family." Pharmaceuticals 15, no. 1 (December 25, 2021): 30. http://dx.doi.org/10.3390/ph15010030.
Анотація:
Rheumatoid arthritis (RA) is a chronic disease characterized by bone joint damage and incapacitation. The mechanism underlying RA pathogenesis is autoimmunity in the connective tissue. Cytokines play an important role in the human immune system for signal transduction and in the development of inflammatory responses. Janus kinases (JAK) participate in the JAK/STAT pathway, which mediates cytokine effects, in particular interleukin 6 and IFNγ. The discovery of small molecule inhibitors of the JAK protein family has led to a revolution in RA therapy. The novel JAK inhibitor upadacitinib (RinvoqTM) has a higher selectivity for JAK1 compared to JAK2 and JAK3 in vivo. Currently, details on the molecular recognition of JAK1 by upadacitinib are not available. We found that characteristics of hydrogen bond formation with the glycine loop and hinge in JAKs define the selectivity. Our molecular modeling study could provide insight into the drug action mechanism and pharmacophore model differences in JAK isoforms.
20
Moser, Bernhard, Sophie Edtmayer, Agnieszka Witalisz-Siepracka, and Dagmar Stoiber. "The Ups and Downs of STAT Inhibition in Acute Myeloid Leukemia." Biomedicines 9, no. 8 (August 19, 2021): 1051. http://dx.doi.org/10.3390/biomedicines9081051.
Анотація:
Aberrant Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling is implicated in the pathogenesis of acute myeloid leukemia (AML), a highly heterogeneous hematopoietic malignancy. The management of AML is complex and despite impressive efforts into better understanding its underlying molecular mechanisms, survival rates in the elderly have not shown a substantial improvement over the past decades. This is particularly due to the heterogeneity of AML and the need for personalized approaches. Due to the crucial role of the deregulated JAK-STAT signaling in AML, selective targeting of the JAK-STAT pathway, particularly constitutively activated STAT3 and STAT5 and their associated upstream JAKs, is of great interest. This strategy has shown promising results in vitro and in vivo with several compounds having reached clinical trials. Here, we summarize recent FDA approvals and current potential clinically relevant inhibitors for AML patients targeting JAK and STAT proteins. This review underlines the need for detailed cytogenetic analysis and additional assessment of JAK-STAT pathway activation. It highlights the ongoing development of new JAK-STAT inhibitors with better disease specificity, which opens up new avenues for improved disease management.
21
Zhang, Xuekang, Jun Zhou, Qian Hu, Zhengren Liu, Qiuhong Chen, Wenxiang Wang, Huaigen Zhang, Qin Zhang, and Yuanlu Huang. "The Role of Janus Kinase/Signal Transducer and Activator of Transcription Signalling on Preventing Intestinal Ischemia/Reperfusion Injury with Dexmedetomidine." Journal of Nanoscience and Nanotechnology 20, no. 5 (May 1, 2020): 3295–302. http://dx.doi.org/10.1166/jnn.2020.16416.
Анотація:
Dexmedetomidine (Dex) works as a crucial agent for the treatment of intestinal ischemia/reperfusion (I/R), but its mechanism remains unclear. Recent articles demonstrated the pivotal role of Janus kinase/signal transducer and activator of transcription (JAK2/STAT3) signalling in I/R. Therefore, it is reasonable to explore the associated mechanism of JAK2/STAT3 signalling in Dex treatment. The study purpose was to evaluate the JAK2/STAT3 signalling regulatory mechanisms of Dex in preventing I/R. Anaesthetized rats were subjected to superior mesenteric artery occlusion consisting of 1 h of ischemia and 2 h of reperfusion while served as controls. Animals received subcutaneous administration of 50 μg/kg Dex, JAK1 and JAK2 inhibitor, Ruxolitinib, selective JAK2 inhibitor, 10 mg/kg AG490 or STAT inhibitor and 0.4 mg/kg rapamycin; or Dex-treatment in the presence of α2-adrenoceptor antagonists Atip or Dex-treatment alone after I/R. Injury was scored histologically, apoptosis was detected via the apoptotic mediators caspase-3 and Bcl-2/Bax and the degree of activation of the JAK/STAT pathway was evaluated. Dex inhibited I/R injury by decreasing apoptosis significantly with rescue of cleaved caspase-3 and the Bcl-2/Bax ratio. Furthermore, phosphorylation of JAK2, STAT1 and STAT3 was affected, suggesting the involvement of activated JAK/STAT in response to Dex. Meanwhile, the JAK2 or STAT inhibitors AG490 and rapamycin, but not Ruxolitinib, exhibited a similar but even greater JAK2 and STAT3 regulatory effect, thus leading to a greater benefit. JAK2/STAT3 activation is crucial to the diminishing effect of Dex on mesenteric I/R injury; however, the efficacy and timing of Dex administration should be considered in clinical practice.
22
Zheng, Ying, Hongwei Qin, Stuart J. Frank, Luqin Deng, David W. Litchfield, Ayalew Tefferi, Animesh Pardanani, et al. "A CK2-dependent mechanism for activation of the JAK-STAT signaling pathway." Blood 118, no. 1 (July 7, 2011): 156–66. http://dx.doi.org/10.1182/blood-2010-01-266320.
Анотація:
Abstract JAK-STAT signaling is involved in the regulation of cell survival, proliferation, and differentiation. JAK tyrosine kinases can be transiently activated by cytokines or growth factors in normal cells, whereas they become constitutively activated as a result of mutations that affect their function in tumors. Specifically, the JAK2V617F mutation is present in the majority of patients with myeloproliferative disorders (MPDs) and is implicated in the pathogenesis of these diseases. In the present study, we report that the kinase CK2 is a novel interaction partner of JAKs and is essential for JAK-STAT activation. We demonstrate that cytokine-induced activation of JAKs and STATs and the expression of suppressor of cytokine signaling 3 (SOCS-3), a downstream target, are inhibited by CK2 small interfering RNAs or pharmacologic inhibitors. Endogenous CK2 is associated with JAK2 and JAK1 and phosphorylates JAK2 in vitro. To extend these findings, we demonstrate that CK2 interacts with JAK2V617F and that CK2 inhibitors suppress JAK2V617F autophosphorylation and downstream signaling in HEL92.1.7 cells (HEL) and primary cells from polycythemia vera (PV) patients. Furthermore, CK2 inhibitors potently induce apoptosis of HEL cells and PV cells. Our data provide evidence for novel cross-talk between CK2 and JAK-STAT signaling, with implications for therapeutic intervention in JAK2V617F-positive MPDs.
23
Hu, Cheng-Ping, Jun-Tao Feng, Yu-Ling Tang, Jin-Qi Zhu, Min-Juan Lin, and Ming-En Yu. "LIF Upregulates Expression of NK-1R in NHBE Cells." Mediators of Inflammation 2006 (2006): 1–8. http://dx.doi.org/10.1155/mi/2006/84829.
Анотація:
Leukemia inhibitory factor (LIF), a cytokine at the interface between neurobiology and immunology, is mainly mediated through JAK/STAT pathway and MAPK/ERK pathway. Evidence suggested LIF is related to the higher expression of neurokinin-1 receptor (NK-1R) in asthma. In this study, the immunohistochemistry stain showed the expressions of NK-1R, LIF, p-STAT3, and p-ERK1/2 in the lung tissues of allergic rats were increased compared with the controls, and the main positive cell type was airway epithelial cell. Normal human bronchial epithelial cells were treated with LIF in the presence or absence of AG490 (JAK2 inhibitor), PD98059 (MEK inhibitor), and the siRNA against STAT3. Western blot and RT-PCR indicated that LIF induced the expression of NK-1R, which was inhibited by the inhibitors mentioned above. No significant interaction was found between JAK/STAT pathway and MAPK/ERK pathway. In summary, bronchial epithelial cell changes in asthma are induced by LIF which promotes the expression of NK-1R, and JAK/STAT pathway and MAPK/ERK pathway may participate in this process.
24
Kim, Jung Eun, Yu Jin Lee, Hye Ree Park, Dong Geon Lee, Kwan Ho Jeong, and Hoon Kang. "The Effect of JAK Inhibitor on the Survival, Anagen Re-Entry, and Hair Follicle Immune Privilege Restoration in Human Dermal Papilla Cells." International Journal of Molecular Sciences 21, no. 14 (July 20, 2020): 5137. http://dx.doi.org/10.3390/ijms21145137.
Анотація:
Topical or systemic administration of JAK inhibitors has been shown to be a new treatment modality for severe alopecia areata (AA). Some patients show a good response to JAK inhibitors, but frequently relapse after cessation of the treatment. There have been no guidelines about the indications and use of JAK inhibitors in treating AA. The basic pathomechanism of AA and the relevant role of JAK inhibitors should support how to efficiently use JAK inhibitors. We sought to investigate the effect of JAK1/2 inhibitor on an in vitro model of AA and to examine the possible mechanisms. We used interferon gamma-pretreated human dermal papilla cells (hDPCs) as an in vitro model of AA. Ruxolitinib was administered to the hDPCs, and cell viability was assessed. The change of expression of the Wnt/β-catenin pathway, molecules related to the JAK-STAT pathway, and growth factors in ruxolitinib-treated hDPCs was also examined by reverse transcription PCR and Western blot assay. We examined immune-privilege-related molecules by immunohistochemistry in hair-follicle culture models. Ruxolitinib did not affect the cell viability of the hDPCs. Ruxolitinib activated several molecules in the Wnt/β-catenin signaling pathway, including Lef1 and β-catenin, and suppressed the transcription of DKK1 in hDPCs, but not its translation. Ruxolitinib reverted IFN-γ-induced expression of caspase-1, IL-1β, IL-15, and IL-18, and stimulated several growth factors, such as FGF7. Ruxolitinib suppressed the phosphorylation of JAK1, JAK2 and JAK3, and STAT1 and 3 compared to IFN-γ pretreated hDPCs. Ruxolitinib pretreatment showed a protective effect on IFN-γ-induced expression of MHC-class II molecules in cultured hair follicles. In conclusion, ruxolitinib modulated and reverted the interferon-induced inflammatory changes by blocking the JAK-STAT pathway in hDPCs under an AA-like environment. Ruxolitinib directly stimulated anagen-re-entry signals in hDPCs by affecting the Wnt/β-catenin pathway and promoting growth factors in hDPCs. Ruxolitinib treatment prevented IFN-γ-induced collapse of hair-follicle immune privilege.
25
Karati, Dipanjan, Kakasaheb Ramoo Mahadik, Piyush Trivedi, and Dileep Kumar. "The Emerging Role of Janus Kinase Inhibitors in the Treatment of Cancer." Current Cancer Drug Targets 22, no. 3 (March 2022): 221–33. http://dx.doi.org/10.2174/1568009622666220301105214.
Анотація:
Abstract: Cancer is a leading cause of death worldwide. The Janus kinase (JAK) signal transducer and activator of transcription (STAT) signalling pathway are activated abnormally, which promotes carcinogenesis. Several cytokines are important cancer drivers. These proteins bind to receptors and use the Janus kinase (JAK) and STAT pathways to communicate their responses. Cancer risks are linked to genetic differences in the JAK-STAT system. JAK inhibitors have been shown to reduce STAT initiation, tissue propagation, and cell existence in preclinical investigations involving solid tumour cell line models. JAK inhibitors, notably ruxolitinib, JAK1 or 2 blockers, make cell lines and mouse models more susceptible to radiotherapy, biological response modifier therapy, and oncolytic viral treatment. Numerous JAK antagonists have been or are now being evaluated in cancerous patients as monotherapy or by combining with other drugs in clinical studies. In preclinical investigations, certain JAK inhibitors showed promising anticancer effects; however, clinical trials explicitly evaluating their effectiveness against the JAK/STAT system in solid tumours have yet to be completed. JAK inhibition is a promising strategy to target the JAK/STAT system in solid tumours, and it deserves to be tested further in clinical studies. The function of directing Janus kinases (JAKs), an upstream accelerator of STATs, as a technique for lowering STAT activity in various malignant circumstances is summarized in this article, which will help scientists to generate more specific drug molecules in the future.
26
Kapuria, Vaibhav, Geoffrey Bartholomeusz, Ling-Yuan Kong, William Bornmann, Zhenghong Peng, Ashutosh Pal, David Maxwell, Moshe Talpaz, and Nicholas Donato. "A Novel Small-Molecule Approach To Inhibit Jak2 Tyrosine Kinase Signaling." Blood 110, no. 11 (November 16, 2007): 1556. http://dx.doi.org/10.1182/blood.v110.11.1556.1556.
Анотація:
Abstract Jak kinases are non-receptor protein tyrosine kinases that play a pivotal role in cytokine/growth factor signaling through phosphorylation of specific proteins such as the Stat molecules. Activated Stats translocate to the nucleus where they mediate transcription of several target genes involved in cell cycle progression and survival (Bcl-xL, cyclin D1, c-myc, survivin. Many tumors have highly activated Stats that are associated with aberrant Jak2 regulation and recent studies have shown that activating mutations in Jak2 (V617F) play a key role in many myeloproliferative disorders such as polycythemia vera and essential thrombocythemia. Jak inhibitors may be useful in treating many diseases with aberrant Jak2/Stat signaling. The most commonly used inhibitor of Jak2 is the tyrphostin AG490, which inhibits Stat3 activation by preventing its tyrosine phosphorylation. However AG490 has limited in vivo efficacy and must be administered at high concentrations (>50 μM) for anti-tumor effects. We describe here a new class of compounds, termed degrasyns, that block Jak2 mediated activation of Stat3 in intact cells at high nM to low μM concentrations. Degrasyns (WP1130/CP2005) did not directly inhibit Jak2 tyrosine kinase activity but suppressed Stat3 activation by reducing the cytoplasmic levels of Jak2. Degrasyn-mediated Jak2 down-regulation was rapid (complete in 2 hrs) and not inhibited by proteasomal, lysosomal, or serine/threonine protease inhibitors. Biochemical studies and confocal microscopy show that degrasyn induces translocation of Jak2 from the plasma membrane/cytosolic fraction into the cytoskeletal fraction and this altered partitioning of Jak2 was associated with loss of cytokine-mediated Stat activation by degrasyn. Jak2 translocation was associated with tyrosine phosphorylation of specific proteins which complex with Jak2. Lyn kinase in the cytoskeletal fraction was highly activated by degrasyn in multiple hematopoetic tumors (multiple myeloma, mantle cell lymphoma, leukemias). Jak2 translocation and Stat inhibition by degrasyn is mechanistically distinct from “classical” Jak2 inhibitors and is not associated with a translocation of other kinases or cytokine signaling molecules in the Jak2 cascade (IL-6R, gp130, Lyn, Btk, Hck, Akt, PI-3K, Erk, Src, Jak1). Degrasyn induces cytoskeletal translocation of both wild-type and mutant (V617F) Jak2 and was associated with induction of apoptosis in HEL cells expressing the Jak2 V617F mutation. These results suggest that degrasyn suppresses Jak/Stat signaling through a unique mechanism involving translocation of Jak2 into a signal transduction incompetent compartment and may be used to investigate a novel form of Stat suppression. Degrasyn may also have anti-tumor effects on cells with aberrant activation of Jak/Stat signaling.
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Springuel, Lorraine, Tekla Hornakova, Elisabeth Losdyck, Fanny Lambert, Emilie Leroy, Stefan N. Constantinescu, Elisabetta Flex, Marco Tartaglia, Laurent Knoops, and Jean-Christophe Renauld. "Cooperating JAK1 and JAK3 mutants increase resistance to JAK inhibitors." Blood 124, no. 26 (December 18, 2014): 3924–31. http://dx.doi.org/10.1182/blood-2014-05-576652.
Анотація:
Key PointsCells transformed by activating JAK1 mutations become resistant to JAK inhibitor by acquiring activating mutations in JAK3 and vice versa. JAK1 and JAK3 mutants cooperatively activate STAT transcription factors.
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Sonkin, Dmitriy, Catherine Regnier, Xianhui Rong, Christie Fanton, Michael Palmer, Jocelyn Holash, Matthew Squires, et al. "Identification of pSTAT5 gene signature in hematologic malignancy." Journal of Clinical Oncology 31, no. 15_suppl (May 20, 2013): 7111. http://dx.doi.org/10.1200/jco.2013.31.15_suppl.7111.
Анотація:
7111 Background: The JAK/STAT pathway is an important signaling pathway downstream of multiple cytokine and growth factor receptors. Receptor-associated JAKs are activated following receptor-ligand binding. Activated JAKs phosphorylate STAT proteins, which then dimerize and translocate to the nucleus where they modulate the expression of target genes. Dysregulated JAK/STAT signaling has been implicated in the pathogenesis of multiple human malignancies. Activating mutations in JAK2 and the associated activation of STAT5 in myeloproliferative neoplasia is one example of the involvement of this pathway in human cancer. Additionally, overactivated JAK/STAT signaling has been suggested as a survival mechanism in several human cancers. Given the importance of JAK/STAT dysregulation in human diseases, it is important to identify patients with an overactivated JAK/STAT pathway for possible treatment with JAK inhibitors. Thus, we developed a gene signature assay to detect overactivated JAK/STAT5 signaling. Methods: The cancer cell line encyclopedia (CCLE) and associated gene-expression data were used to correlate the activation status of STAT5 with the induction of a set of STAT5 target genes. First, we used 27 tumor cell lines of hematologic lineage, with predetermined phosphorylated STAT5 (pSTAT5) status, to derive STAT5 activation gene signatures. Next, the putative gene signatures were validated against a different set of 13 hematologic tumor cell lines. Results: With this approach, a collection of 7 target genes were identified (PIM1, CISH, SOCS2, ID1, LCN2, EPOR, and EGR1) whose expression significantly correlated with pSTAT5 status in the 40 hematologic tumor cell lines (P < .0001), either together or in specific subsets of 4 and 6 genes (Table). Conclusions: These 4-, 6-, and 7-gene signatures can be used to stratify or select for a patient population with activated JAK/STAT5 signaling that could potentially benefit from treatments targeting the JAK/STAT5 signaling pathway. [Table: see text]
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Haysen, S., A. L. L. Nielsen, P. Qvist, and T. W. Kragstrup. "POS0038 GENOMICS OF JAK-STAT SIGNALING IN VENOUS THROMBOEMBOLISM." Annals of the Rheumatic Diseases 81, Suppl 1 (May 23, 2022): 234.1–234. http://dx.doi.org/10.1136/annrheumdis-2022-eular.2593.
Анотація:
BackgroundJanus kinase inhibitors (JAKi) have been associated with an increased risk of venous thromboembolism (VTE) [1]. VTE comprises deep vein thrombosis and pulmonary embolism and is associated with complications such as recurrent VTE, post thrombotic syndrome, pulmonary hypertension, and death. These concerns limit the use of JAKi-based therapy. To improve risk stratification and drug development, it is crucial to understand the possible implication of dysregulated JAK-signal transducers and activators of transcription (STAT) signaling in the pathogenesis of VTE.ObjectivesThe objective of this study is to clarify the putative genomic vulnerability to dysregulated JAK-STAT signaling in VTE.MethodsWe are systematically mine and analyze large-scale genomic datasets generated from studies comparing VTE patients with healthy controls. Using VTE genome-wide associated (GWA) summary statistics we evaluate the representation of genes encoding the JAK-STAT pathway (KEGG hsa04630) in associated loci and assess their association to VTE. Further, we examine the genetic VTE risk burden in the chromatin interactome of STAT family transcription factors (TFs). We extract available STAT family (STAT1-3) TF binding site (TFBS) consensus DNA motifs (JASPAR database) and assess the association of genes containing STAT family TFBS within their promotor sequence (TSS -2000bp) to VTE. Through mining of deposited OMICs data from VTE patients, we examine molecular characteristics related to JAK-STAT signaling, including potential enrichment of STAT family TFBSs among query promoter sequences of differently expressed genes (DEGs).ResultsWe do not observe a significant overrepresentation of JAK-STAT genes (ntotal=162) among genes annotated to VTE significant GWA loci (ntotal=147, p=0.48). Similarly, the JAK-STAT gene set show no cumulative association to VTE (p=0.98). Applying the same gene set association approach to the STAT target gene sets (ntotal=4570) does not reveal significant association between VTE and STAT1 (noverlap=10, p=0.47), STAT1:STAT2 heterodimer (noverlap=18, p=0.17) and STAT3 (noverlap=6, p=0.20) target gene sets. At the functional molecular level, we do not see any significant overlap between molecules acting in the JAK-STAT pathway and DEGs (ntotal=507, p=0.06) or differentially abundant proteins (DAPs; ntotal=35, p=0.57). However, we observe a significant overlap between downregulated DEGs (ntotal=362) and the STAT1:STAT2 heterodimer target gene set (ntotal= 2155, noverlap=48, p<0.0001) including downregulation of IL-27RA and CCND3 (Figure 1). Supporting the biological relevance of this finding, we find a weak but statistically significant enrichment of STAT1 TFBS motifs in the promotor sequence of downregulated DEGs compared to non-DEGs (p=0.02).Figure 1.Overlap between STAT1:STAT2 heterodimer gene set and differently expressed genes (DEGs) in venous thromboembolism (VTE)ConclusionHere, we provide a coherent approach to assess the genomic basis for the reported association between JAKi treatment and VTE. Our preliminary data suggest that genes under transcriptional control of STAT family TFs may be dysregulated in VTE patients. It is conceivable, that the genomic actions of JAKi is overlapping with the molecular risk profile of VTE. CCND3 is especially interesting because VTE occurs in up to 10% of patients treated with cyclin-dependent kinase inhibitors such as Palbociclib [2]. Obviously, genomic data mining alone cannot guide medical decision making concerning the use of JAKi. However, our results provide a basis for further investigation of adverse events seen with JAKi.References[1]Charles-Schoeman, C., et al., The Risk of Venous Thromboembolic Events in Patients with RA Aged ≥ 50 Years with ≥ 1 Cardiovascular Risk Factor: Results from a Phase 3b/4 Randomized Safety Study of Tofacitinib vs TNF Inhibitors. Arthritis Rheumatol, 2021; 73 (suppl 10).[2]West, M.T., et al., CDK 4/6 inhibitors are associated with a high incidence of thrombotic events in women with breast cancer in real-world practice. Eur J Haematol, 2021. 106(5): p. 634-642.Disclosure of InterestsStine Haysen: None declared, Ane Langkilde-Lauesen Nielsen: None declared, Per Qvist: None declared, Tue Wenzel Kragstrup Speakers bureau: Speaking fees from Pfizer, Bristol-Myers Squibb, Eli Lilly, Novartis, UCB, and Abbvie., Consultant of: Consultancy fees from Bristol-Myers Squibb and Gilead., Grant/research support from: Research grants from Gilead., Employee of: Co-founder and clinical developer in iBio tech ApS.
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Jeong, Ga Hee, and Ji Hyun Lee. "Dysregulated Hippo Signaling Pathway and YAP Activation in Atopic Dermatitis: Insights from Clinical and Animal Studies." International Journal of Molecular Sciences 24, no. 24 (December 10, 2023): 17322. http://dx.doi.org/10.3390/ijms242417322.
Анотація:
The yes-associated protein (YAP) of the Hippo pathway regulates a variety of target genes involved in cell proliferation, survival, and inflammation. YAP and transcription activator with a PDZ-binding motif (TAZ) proteins act as mediators of the inflammatory response. Still, their role in atopic dermatitis (AD)—particularly, the association with the nuclear factor kappa-B and Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathways—is not fully understood. In this study, we found that YAP, is upregulated in AD patients and NC/Nga mouse model of AD. In addition, inhibition of YAP significantly reduced epidermal cell proliferation by 58% and mast cell numbers by 51% and attenuated the upregulation of both Th1- and Th2-associated cytokines. Among the JAK-STAT family proteins, the expressions of JAK1 and JAK2 and those of STAT1, STAT2, and STAT3 were also downregulated. These findings may explain the role of YAP in AD and suggest YAP inhibitors as promising therapeutic agents for AD.
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Perner, Florian, Felix C. Saalfeld, Tina M. Schnoeder, Denise Wolleschak, Corinna Fahldieck, Satish Ranjan, Berend H. Isermann, et al. "Specificity of JAK-Kinase Inhibition Determines Impact on T-Cell Function." Blood 124, no. 21 (December 6, 2014): 1410. http://dx.doi.org/10.1182/blood.v124.21.1410.1410.
Анотація:
Abstract Inhibitors of JAK2-kinase (Ruxolitinib, Momelotinib) are already approved or currently investigated in advanced clinical trials for treatment of myeloproliferative neoplasia (MPN). Besides their effect on mutated JAK2-kinase these compounds inhibit wildtype JAK and thereby impair JAK-STAT-signaling, which is an important pathway for proliferation and activation of other cell types such as human T-cells. Accumulating evidence suggests that they may also exert substantial immunosuppressive activity. Very recent reports highlighting hepatitis B reactivation complemented the series of severe infections in ruxolitinib-treated patients among which cryptococcus neoformans pneumonia, toxoplasmosis retinitis, disseminated tuberculosis, and progressive multifocal leukencephalopathy are the most alarming. We hypothesized that JAK-kinase inhibitors may act as immunosuppressant drugs by impairment of T-cell responses through inhibition of T-cell signaling (JAK-STAT pathway) and that specificity of JAK-kinase inhibition may be of major importance for the degree of T-cell inhibition. Therefore we investigated the effects of pharmacological JAK-kinase inhibition on healthy donor (HD-) and MPN patient T-cells. Selective inhibitors of JAK2-kinase (BSK805) and JAK3-kinase (BQM245) as well as clinically relevant inhibitors of JAK1/2-kinases (Ruxolitinib and Momelotinib) were used for pharmacologic inhibition. The SRC-kinase inhibitor Dasatinib served as a positive control for T-cell inhibition. Knockdown of specific JAK-kinases by RNAi was used to control for target specificity. In regard to T-cell receptor (TCR)-mediated signaling we investigated bona fide signaling molecules downstream of the TCR by Western Blotting. Besides SRC-kinases like LCK also ZAP70, PLCG1 and the MAPK/ERK pathway have been described to play a pivotal role in T-cell activation. In our data set, selectivity of JAK-kinase inhibition (JAK2, JAK3 or JAK1/2) influenced TCR-signaling in regard to overall tyrosine phosphorylation but also in regard to downstream effectors such as ERK. As activation and proliferation of primary T-cells is a critical step in immune responses against viral and tumor antigens we aimed to investigate the influence of JAK-kinase inhibition on activation and proliferation of human T-cells. T-cells from healthy donors were stimulated using either PHA 0.5% or CD3/CD28 beads to ensure a more T-cell receptor specific stimulation. CD69 expression was used as a marker for T-cell activation and CFSE staining was applied to assess for T-cell proliferation. Using CD3/CD28 stimulation, CD69 expression was almost abrogated following Dasatinib treatment and proliferation was significantly reduced. Applying relevant doses of specific JAK2 and JAK3 inhibitors to isolated T-cells did neither influence CD69 expression nor T-cell proliferation. These findings are confirmed by RNAi. In contrast, clinically relevant doses of JAK1/2 inhibitors Ruxolitinib and Momelotinib, respectively reduced CD69 expression and T-cell proliferation. Likewise, T-cells derived from MPN patients treated with Ruxolitinib revealed decreased CD69 expression and decreased proliferative capacity upon stimulation, compared to untreated patients or HD-controls. In order to investigate T-cell function, we assessed for allo-reactivity in a mixed lymphocyte culture. Human pan-T-cells were co-cultured with allogeneic antigen presenting cells. T-cell reactivity – as measured by 3H-thymidine incorporation – was significantly impaired by Ruxolitinib and Momelotinib. Specific inhibition of JAK2 or JAK3 kinase, however, did not affect T-cell reactivity. These effects could be confirmed using T-cells derived from Ruxolitinib-treated MPN patients. Investigation of leukemia- and virus-antigen-specific T-cell responses are currently under way to gain deeper insight regarding this clinically relevant scenario. Taken together, specificity of JAK-kinase inhibition influences the inhibitory potential on T-cell function. JAK1 kinase seems to play an important role in T-cell activation, as unspecific inhibitors of JAK1 & JAK2 Kinase inhibit T-cell function while selective inactivation of JAK2 kinase leaves T-cell function almost unaffected. Heterogeneity in T-cell function of Ruxolitinib-treated patients is an important finding that deserves detailed investigation. Disclosures Heidel: Novartis: Consultancy.
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Purandare, Ashok V., Animesh Pardanani, Theresa McDevitt, Marco Gottardis, Terra Lasho, Dan You, Louis Lombardo, et al. "Characterization of BMS-911543, a Functionally Selective Small Molecule Inhibitor of JAK2." Blood 116, no. 21 (November 19, 2010): 4112. http://dx.doi.org/10.1182/blood.v116.21.4112.4112.
Анотація:
Abstract Abstract 4112 We report the characterization of BMS-911543, a potent and functionally selective small molecule inhibitor of the Janus kinase family (JAK) member, JAK2. BMS-911543 is a reversible inhibitor of JAK2 with a biochemical IC50 of 0.001 μ M and Ki of 0.48 nM. It has over 74- and 350-fold selectivity against the other JAK family members, JAK3 and JAK1, respectively. Further, examination of > 450 other kinases did not reveal significant inhibitory activity for this JAK2 inhibitor. Functionally, BMS-911543 displayed potent anti-proliferative and pharmacodynamic (PD) effects in mutated JAK2-expressing cell lines dependent upon JAK2-STAT signaling and had little activity in cell types dependent upon other pathways such as JAK1 and JAK3. BMS-911543 was evaluated in colony growth assays using primary progenitor cells isolated from patients with JAK2V617F-positive myeloproliferative disease (MPD) and resulted in an increased anti-proliferative response in MPD cells as compared with those from healthy volunteers. Similar to these in vitro observations, BMS-911543 was also highly active in in vivo models of JAK2-pSTAT signaling in multiple species (mouse, rat, dog and monkey) with sustained pathway suppression being observed after a single oral dose. Additionally, BMS-911543 was evaluated for effects in a JAK2V617F-expressing SET-2 xenograft model system and displayed a minimally effective dose of <2 mg/kg on pSTAT5 pathway suppression, which lasted up to 8 hours. BMS-911543 was also compared to pan-JAK inhibitors in a mouse model of immunosuppression. At low dose levels active in JAK2-dependent PD models, no effects were observed on antigen-induced IgG and IgM production whereas a pan-JAK family inhibitor showed pronounced effects at all dose levels tested. The mechanistic selectivity of BMS-911543 to pan-JAK family inhibitors was extended through comparative analysis of these inhibitors in whole genome gene expression profiling experiments performed in sensitive cell types. In this comparison, BMS-911543 modulated a distinct subset of transcriptional changes as compared to pan-JAK inhibitors, thereby defining a minimal set of transcriptional changes underlying the pharmacologic effects of JAK2 inhibition. Collectively these results define the mechanistic basis for a differential therapeutic index between selective JAK2 and pan-JAK family inhibition pre-clinically and suggest a therapeutic rationale for the further characterization of BMS-911543 in patients with MPD and in other disorders characterized by constitutively active JAK2 signaling. Disclosures: Purandare: Bristol-Myers Squibb: Employment. McDevitt:Bristol-Myers Squibb: Employment. Gottardis:Bristol-Myers Squibb: Employment. You:Bristol-Myers Squibb: Employment. Lombardo:Bristol_Myers Squibb: Employment. Penhallow:Bristol-Myers Squibb: Employment. Vuppugalla:Bristol-Myers Squibb: Employment. Trainor:Bristol-Myers Squibb: Employment. Lorenzi:Bristol-Myers Squibb: Employment.
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Lim, Ken-Hong, Yu-Cheng Chang, Yi-Hao Chiang, Huan-Chau Lin, Ling Huang, Wei-Ting Wang, Ying-Wen Su, Ming-Chih Chang, Yi-Fang Chang, and Caleb Gon-Shen Chen. "Acquired Resistance to JAK Inhibitors in Calr-Mutated Myeloproliferative Neoplasms." Blood 134, Supplement_1 (November 13, 2019): 2970. http://dx.doi.org/10.1182/blood-2019-124420.
Анотація:
Background: Calreticulin (CALR) mutations are one of the major driver mutations in BCL-ABL1-negative myeloproliferative neoplasm (MPN) and are frequently detected in JAK2/MPL-unmutated essential thrombocythemia and primary myelofibrosis. Mutant CALR activates JAK-STAT signaling through an MPL-dependent mechanism to mediate pathogenic thrombopoiesis in MPNs. Although JAK inhibitors such as ruxolitinib can provide important clinical benefits to MPN patients including those harboring CALR mutations, JAK inhibition does not preferentially target the MPN clone and acquired resistance develops over time. We aimed to characterize the mechanisms of acquired resistance to JAK inhibitors in CALR-mutated hematopoietic cells and to screen for novel therapeutic approaches specifically target CALR-mutant cells in this study. Methods: UT-7/TPO-derived cell lines expressing wild-type and type 1 and type 2 mutant CALR (CALRdel52 and CALRins5) were kindly provided by Drs. Komatsu and Araki. JAK2-inhibitor-resistant cells were generated by co-cultured with ruxolitinib and fedratinib (TG101348, a JAK2-selective inhibitor). JAK-STAT signaling was evaluated by Western blot on CALR-wild-type and mutated cells exposed to JAK2 inhibitor compared to untreated cells. For the detection of acquired secondary mutations in CALR-mutated cells exposed to JAK2 inhibitor, whole exome sequencing (WES) was performed using the BGISEQ-500 Sequencing platform (BGI, Shenzhen, China) with the 2 x 100 bp paired-end protocol. Genome Analysis Toolkit was used for variation detection. Reads were aligned to human reference genome hg19 using BWA version 0.7.15. Targeted resequencing was performed on leukocytes from patients with MPN who had been treated with ruxolitinib. Screening with chemical libraries/novel compounds will be conducted on UT7/TPO-CALR cell lines. Results: Compared to the parental cells, ruxolitinib-resistant UT7/TPO-CALR mutant cell lines have developed significant cross resistance to other JAK inhibitor as shown in the cell viability study. Signalling downstream of JAK2 in all 3 inhibitor-naïve UT-7/TPO/CALR parental cell lines was inhibited by acute treatment of ruxolitinib as shown on Western blot. Whereas, constitutive JAK2 activation was observed in all 3 inhibitor-resistant UT-7/TPO/CALR cell lines. No change in the expression of Epo and MPL receptors in these cell lines was found. Interestingly, constitutive JAK3 activation was also seen in inhibitor-resistant UT-7/TPO/CALR cells in comparison with parental cells. These findings indicated the presence of transphosphorylation by JAK3 in inhibitor-resistant UT-7/TPO/CALR cell lines. In addition, the results of WES identified several acquired secondary mutations in 3 inhibitor-resistant UT-7/TPO/CALR cell lines including SH2B1, ABCC1, HOXB3 and KRTAP4-5. No acquired secondary mutation was identified in CALR and other genes involved in JAK-STAT signaling. Acquired secondary mutation will be screened in primary MPN patients' samples treated with JAK inhibitor. Type II JAK inhibitor such as BBT-594 has been shown to inhibit JAK activation and signaling in JAK-persistent/resistant cells. Conclusions: Our results confirmed that the in vitro efficacy of JAK2 inhibition on CALR-mutant cells. Our data also suggested that JAK2 transphosphorylation and acquired secondary mutations could be underlying mechanisms for acquired resistance to JAK inhibitors in CALR-mutated cells. Novel therapeutics approaches should be developed to overcome acquired resistance in CALR-mutated cells. Disclosures No relevant conflicts of interest to declare.
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Rodman, Esther, Michael Emch, Elizabeth Bruinsma, Xiaonan Hou, John Weroha, and John Hawse. "Abstract 1129: Interrogating JAK/STAT signaling in ovarian cancer as a potential oncogenic driver and therapeutic target." Cancer Research 82, no. 12_Supplement (June 15, 2022): 1129. http://dx.doi.org/10.1158/1538-7445.am2022-1129.
Анотація:
Abstract Ovarian cancer is the 7th most common cancer in women. It is the most fatal of all female reproductive cancers, due to the 5-year overall survival of 10-30% and over half of patients being diagnosed with late-stage disease. Despite initial response to front line platinum- and taxol-based chemotherapies, over 70% of patients develop recurrent and chemotherapy resistant disease and nearly all of these women die of their disease. Recently, the use of targeted therapies such as bevacizumab and PARP inhibitors have been shown to improve progression-free survival. However, these regimens have thus far failed to improve overall survival in patients without specific genetic signatures, highlighting the urgent need for alternative therapies. We have identified lestaurtinib as a potent inhibitor of many ovarian cancer cell lines, including platinum and PARP inhibitor resistant models, and patient derived organoid models. RNA-sequencing following lestaurtinib treatment identified JAK/STAT signaling as one of the most profoundly downregulated pathways. Additionally, it was recently reported via single cell RNA sequencing of patient tumors that downstream mediators of the JAK/STAT pathway are among the most highly expressed genes in ovarian tumor cells. Further, we have discovered that STAT1 and STAT3 are constitutively activated in chemotherapy and PARP inhibitor resistant cell lines as reflected by high levels of Tyr701/705 and Ser727 phosphorylation suggesting induction of this pathway may drive resistance. Selective siRNA-mediated knockdown of STAT1/3 resulted in significant growth inhibition confirming their importance in maintaining cell viability. Surprisingly, we have identified profound differences in the ability of various JAK/STAT inhibitors to suppress ovarian cancer cell growth. For example, ruxolitinib, the only JAK/STAT inhibitor currently in clinical trials for ovarian cancer, failed to inhibit the growth sensitive, platinum resistant or PARP inhibitor resistant cell lines. Our preliminary data indicate that JAK/STAT inhibitor efficacy in preventing ovarian cancer cell growth is related to their ability to block specific phosphorylation events on STAT1/3 proteins. We believe that precise and selective inhibition of STAT1 and STAT3 signaling represents a robust, durable, and novel approach for the treatment of highly aggressive and resistant forms of ovarian cancer. Further we plan to elucidate the molecular mechanisms by which STAT1 and STAT3 function to support ovarian cancer cell viability and growth, in order to substantially advance our understanding of JAK/STAT signaling in ovarian cancer and to identify the most effective ways to pharmacologically inhibit JAK/STAT signaling in ovarian cancer cells. Outcomes from this work will have both immediate and long-term impacts for our patients and will lay the foundation for future biomarker-driven clinical trials. Citation Format: Esther Rodman, Michael Emch, Elizabeth Bruinsma, Xiaonan Hou, John Weroha, John Hawse. Interrogating JAK/STAT signaling in ovarian cancer as a potential oncogenic driver and therapeutic target [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1129.
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Clarke, A., J. Di Paolo, B. Downie, A. Meng, N. Mollova, Y. Yu, and P. Han. "P460 Evaluation of potential mechanisms underlying the safety observations of filgotinib in clinical studies in rheumatoid arthritis." Journal of Crohn's and Colitis 14, Supplement_1 (January 2020): S409. http://dx.doi.org/10.1093/ecco-jcc/jjz203.589.
Анотація:
Abstract Background Inhibitors of the Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway have demonstrated efficacy in the treatment of rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). Differences in selectivity of JAK inhibitors for JAK1, JAK2, JAK3 and TYK2 may influence their respective safety profiles, and the mechanisms responsible are not currently known. Filgotinib (FIL), a JAK1 inhibitor, did not negatively impact haemoglobin, LDL:HDL ratios or natural killer (NK) cell counts in clinical trials. Here, we compare the in vitro mechanistic profiles of four JAK inhibitors at clinically relevant doses. Methods JAK inhibitors (FIL, FIL metabolite [GS-829845], baricitinib [BARI], tofacitinib [TOFA], and upadacitinib [UPA]) were evaluated in vitro in human-cell-based assays. Growth of erythroid progenitors from human cord blood CD34+ cells was assessed using a HemaTox™ liquid expansion assay, NK cell proliferation was induced by IL-15 and LXR agonist-induced cholesteryl ester transfer protein (CETP) expression was assessed in the hepatic cell line, HepG2. Using assay-generated IC50 values and the reported human plasma concentrations from clinical studies, we calculated the target coverage for each JAK inhibitor at clinically relevant doses. The activity of FIL in humans was based on PK/PD modelling of FIL + GS-829845. Results Inhibition of cellular activity was calculated for each JAK inhibitor based on in vitro dose-response data, human exposure data and modelled PK/PD relationships. At clinically relevant doses, FIL resulted in lower calculated inhibition of NK cell proliferation compared with other JAK inhibitors. FIL 100 mg and 200 mg also reduced CETP expression, whereas other JAK inhibitors had no effect. There was no difference in the effect of FIL vs. other JAK inhibitors on erythroid progenitor cell differentiation or maturation. Conclusion FIL, a JAK1 inhibitor, resulted in less inhibition of NK cell proliferation compared with BARI, TOFA, and UPA. FIL also reduced LXR agonist-induced CETP expression, while the other inhibitors did not alter these levels. These results provide a potential mechanistic link between the observed reduction of CETP concentration following FIL treatment and the previously observed reduction in the LDL:HDL ratio in RA patients.
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Ross, David M., Jeffrey J. Babon, Denis Tvorogov, and Daniel Thomas. "Persistence of myelofibrosis treated with ruxolitinib: biology and clinical implications." Haematologica 106, no. 5 (January 21, 2021): 1244–53. http://dx.doi.org/10.3324/haematol.2020.262691.
Анотація:
Activation of JAK-STAT signaling is one of the hallmarks of myelofibrosis, a myeloproliferative neoplasm that leads to inflammation, progressive bone marrow failure, and a risk of leukemic transformation. Around 90% of patients with myelofibrosis have a mutation in JAK2, MPL, or CALR: so-called ‘driver’ mutations that lead to activation of JAK2. Ruxolitinib, and other JAK2 inhibitors in clinical use, provide clinical benefit but do not have a major impact on the abnormal hematopoietic clone. This phenomenon is termed ‘persistence’, in contrast to usual patterns of resistance. Multiple groups have shown that type 1 inhibitors of JAK2, which bind the active conformation of the enzyme, lead to JAK2 becoming resistant to degradation with consequent accumulation of phospho-JAK2. In turn, this can lead to exacerbation of inflammatory manifestations when the JAK inhibitor is discontinued, and it may also contribute to disease persistence. The ways in which JAK2 V617F and CALR mutations lead to activation of JAK-STAT signaling are incompletely understood. We summarize what is known about pathological JAK-STAT activation in myelofibrosis and how this might lead to future novel therapies for myelofibrosis with greater disease-modifying potential.
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Montero, Paula, Javier Milara, Inés Roger, and Julio Cortijo. "Role of JAK/STAT in Interstitial Lung Diseases; Molecular and Cellular Mechanisms." International Journal of Molecular Sciences 22, no. 12 (June 9, 2021): 6211. http://dx.doi.org/10.3390/ijms22126211.
Анотація:
Interstitial lung diseases (ILDs) comprise different fibrotic lung disorders characterized by cellular proliferation, interstitial inflammation, and fibrosis. The JAK/STAT molecular pathway is activated under the interaction of a broad number of profibrotic/pro-inflammatory cytokines, such as IL-6, IL-11, and IL-13, among others, which are increased in different ILDs. Similarly, several growth factors over-expressed in ILDs, such as platelet-derived growth factor (PDGF), transforming growth factor β1 (TGF-β1), and fibroblast growth factor (FGF) activate JAK/STAT by canonical or non-canonical pathways, which indicates a predominant role of JAK/STAT in ILDs. Between the different JAK/STAT isoforms, it appears that JAK2/STAT3 are predominant, initiating cellular changes observed in ILDs. This review analyzes the expression and distribution of different JAK/STAT isoforms in ILDs lung tissue and different cell types related to ILDs, such as lung fibroblasts and alveolar epithelial type II cells and analyzes JAK/STAT activation. The effect of JAK/STAT phosphorylation on cellular fibrotic processes, such as proliferation, senescence, autophagy, endoplasmic reticulum stress, or epithelial/fibroblast to mesenchymal transition will be described. The small molecules directed to inhibit JAK/STAT activation were assayed in vitro and in in vivo models of pulmonary fibrosis, and different JAK inhibitors are currently approved for myeloproliferative disorders. Recent evidence indicates that JAK inhibitors or monoclonal antibodies directed to block IL-6 are used as compassionate use to attenuate the excessive inflammation and lung fibrosis related to SARS-CoV-2 virus. These altogether indicate that JAK/STAT pathway is an attractive target to be proven in future clinical trials of lung fibrotic disorders.
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Banes, Amy K., Séan Shaw, John Jenkins, Heather Redd, Farhad Amiri, David M. Pollock, and Mario B. Marrero. "Angiotensin II blockade prevents hyperglycemia-induced activation of JAK and STAT proteins in diabetic rat kidney glomeruli." American Journal of Physiology-Renal Physiology 286, no. 4 (April 2004): F653—F659. http://dx.doi.org/10.1152/ajprenal.00163.2003.
Анотація:
Clinical and animal studies show that treatment with angiotensin-converting enzyme (ACE) inhibitors or ANG II-receptor antagonists slows progression of nephropathy in diabetes, indicating ANG II plays an important role in its development. We previously reported that hyperglycemia augments both ANG II-induced growth and activation of Janus kinase (JAK)2 and signal transducers and activators of transcription (STAT) proteins in cultured rat mesangial cells. Furthermore, we demonstrated that the tyrosine kinase enzyme JAK2 plays a key role in both ANG II- and hyperglycemia-induced growth in these cells. We hypothesized that the ACE inhibitor captopril and the ANG II-receptor antagonist candesartan would hinder hyperglycemic-induced activation of JAK and STAT proteins in rat glomeruli, demonstrating that ANG II plays an important role in the activation of these proteins in vivo. Adult male Sprague-Dawley rats were given either streptozotocin (STZ; 60 mg/kg iv) or vehicle, and glomeruli were isolated 2 wk later. Activation of JAK and STAT proteins was evaluated by Western blot analysis for specific tyrosine phosphorylation. Groups of rats were given captopril (75–85 mg·kg-1·day-1), candesartan (10 mg· kg-1·day-1), or the JAK2 inhibitor AG-490 (5 mg·kg-1·day-1) for the study's duration. STZ stimulated glomerular phosphorylation of JAK2, STAT1, STAT3, and STAT5. Phosphorylation was reduced in rats treated with captopril, candesartan, and AG-490. Furthermore, both candesartan and AG-490 inhibited STZ-induced increases in urinary protein excretion. In conclusion, our studies demonstrate that hyperglycemia induces activation of JAK2 and the STATs in vivo via an ANG II-dependent mechanism and that these proteins may be involved in the early kidney damage associated with diabetes.
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Jang, Sun Hee, and Ji Hyeon Ju. "Janus kinase inhibitors for the treatment of rheumatoid arthritis." Journal of the Korean Medical Association 64, no. 2 (February 10, 2021): 105–8. http://dx.doi.org/10.5124/jkma.2021.64.2.105.
Анотація:
Rheumatoid arthritis is a chronic inflammatory destructive disorder that affects the joints, muscles, and tendons accompanying various extra-articular manifestations. Traditional disease-modifying anti-rheumatic drugs (DMARDs) represent the basic treatment for rheumatoid arthritis. Over the last 20 years, biologic DMARDs (tumor necrosis factor inhibitors, interleukin-1 inhibitors, interleukin-6 inhibitors, T cell inhibitors, and B cell inhibitors) have been widely used as a novel class of DMARDs that have efficacy and efficiency. Discovery of the underlying pathogenesis of autoimmune disease enables us to develop new target therapies such as a Janus kinase (JAK) inhibitor. Activated JAK is known to activate signal transducers as well as activators of transcription (STAT) signaling. A JAK inhibitor is a type of medication that functions by inhibiting the JAK-STAT signaling pathway. In addition, it is easy to take a JAK inhibitor orally. In Korea, several JAK inhibitors have been approved. This review describes the types of JAK inhibitors, recommended doses, side effects, and updated European Alliance of Associations for Rheumatology guidelines. Clinicians should more often consider JAK inhibitors in the treatment of refractory rheumatoid arthritis in current rheumatology clinics
40
Simon, Amy R., Satoe Takahashi, Mariano Severgnini, Barry L. Fanburg, and Brent H. Cochran. "Role of the JAK-STAT pathway in PDGF-stimulated proliferation of human airway smooth muscle cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 282, no. 6 (June 1, 2002): L1296—L1304. http://dx.doi.org/10.1152/ajplung.00315.2001.
Анотація:
Airway remodeling, as manifested by an increase in airway smooth muscle mass, mucous gland hyperplasia, and subepithelial fibrosis, contributes to the airway hyperresponsiveness and fixed obstruction seen in some asthmatic patients. Here we investigated whether the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway contributes to platelet-derived growth factor (PDGF)-stimulated mitogenesis of human airway smooth muscle cells (HASMC). PDGF treatment of quiescent HASMC resulted in the rapid tyrosine phosphorylation and DNA binding of STAT1 and STAT3. This phosphorylation was blocked by inhibition of Src and JAK2 kinases. In addition, STAT activation by PDGF was found to be redox dependent. Moreover, PDGF-induced thymidine uptake was completely blocked by pretreatment of HASMC with the STAT kinase inhibitors AG-490, SU-6656, and PP2. Interestingly, the JAK pathway was required for HASMC mitogenesis independently of mitogen-activated protein kinase activation. Inhibition of the Src and JAK kinases blocked PDGF-stimulated gene expression of the STAT target genes cyclin D1 and c- myc. These results indicate that the JAK-STAT pathway contributes to PDGF-induced mitogenesis, and thus this pathway may be important in the airway remodeling seen in some asthmatic patients.
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Liu, Liqin, Violeta Yu, Jeanne Pistillo, Josie Lee, Laurie B. Schenkel, Stephanie Geuns-Meyer, Ivonne Archibeque, Angus Sinclair, Renee Emkey, and Graham Molineux. "New Insights on Assessing Intra-Family Selectivity for Jak2 Inhibitors." Blood 118, no. 21 (November 18, 2011): 5150. http://dx.doi.org/10.1182/blood.v118.21.5150.5150.
Анотація:
Abstract Abstract 5150 Essential thrombocythemia (ET), polycythemia vera (PV) and myelofibrosis (MF) are myeloproliferative disorders (MPDs) characterized by a chronic over-production of cells of one or more blood cell lineages and/or bone marrow fibrosis which may, on occasion, progress to acute myeloid leukemia. The V617F gain of function mutation in the pseudokinase domain of Jak2, which results in constitutive activation of Jak2, is the most frequent mutation associated with MPD. Constitutively activated Jak2 can lead to dysregulated downstream signaling pathways (STAT, MAP kinase, and PI3 kinase) which in turn trigger abnormal growth, survival and differentiation of hematopoietic progenitors. Therefore, inhibition of constitutively activated Jak2 may offer therapeutic potential. Designing a Jak2V617F specific inhibitor encounters challenges due to the lack of enzymatic activity of the pseudokinase domain of Jak2. In lieu of a Jak2V617F mutant selective inhibitor, a highly selective inhibitor of Jak2 is likely an attainable goal. Jak2 is a member of the Jak family of kinases including Jak1, Jak3, and Tyk2. Highly selective Jak2 inhibitors may provide a better safety margin in chronic dosing settings in ET and PV patients since inhibiting other Jak family members could cause side-effects such as immunosuppression. Attaining the desired selectivity of Jak2 inhibition versus the other family members has been challenging and few compounds have been reported to date that have the desired Jak2 selectivity. This can be attributed to the high homology of the ATP binding pocket among Jak family members, but is also hampered by a lack of assays capable of distinguishing the Jak-selectivity profile in a physiologically relevant setting. We compared the potency and selectivity of compounds tested in a pSTAT5 AlphaScreen® assay panel consisting of isogenic Ba/F3 cell lines individually expressing translocated ETS leukemia (TEL) fusions of each Jak-family member (Ba/F3-TEL-Jak) with data from corresponding Jak enzyme assays. Here we report that the selectivity of inhibitor compounds illustrated in enzyme assays did not correlate with the selectivity profile in cell lines due to different shifts in potency for each family member between enzyme and cells (Figure 1). As a consequence the selectivity of compounds for Jak2 against Jak1 observed in enzyme assays may be reduced or reversed in cellular assays. On the other hand, Jak2 selectivity over Jak3 seen in the enzyme assays was conserved in the cellular assay. Thus, we propose that compounds that exhibit greater potency on Jak2 compared to Jak1 in the enzyme assays are needed and should be the main focus of medicinal chemistry efforts in order to attain Jak2 selectivity over Jak1 in a cellular context. We also compared the potency and selectivity of compounds in the isogenic Ba/F3-TEL-Jak cell lines with data obtained with cytokine stimulated peripheral blood mononuclear cells (PBMCs). The potency and selectivity of compounds in PBMCs are determined by measuring the inhibition of phosphorylation of STAT5 in TPO or GM-CSF stimulated platelets or monocytes (mediated by Jak2) and in IL-2 stimulated lymphocytes (mediated by Jak1 and Jak3). We found that potency correlated well between PBMCs and Ba/F3-TEL-Jak2 cells, and the rank order of compounds based on IC50 values obtained with Ba/F3-TEL-Jak cell lines were conserved well in PBMCs; the compound selectivity profiles derived from the Ba/F3-TEL-Jak cell assays were predictive of Jak2 selectivity profiles obtained in the PBMC assays. Therefore, inclusion of Ba/F3-TEL-Jak pSTAT5 cellular assays may be useful for Jak family inhibitor development. Our results also suggest that relying solely on enzyme potency and selectivity data can be misleading, and that evaluating cellular selectivity in a biologically relevant context may provide a more meaningful understanding of selectivity and lead to the development of more selective Jak2 compounds. Disclosures: Liu: Amgen, Inc: Employment. Yu:Amgen: Employment. Pistillo:Amgen: Employment. Lee:Amgen: Employment. Schenkel:Amgen: Employment. Geuns-Meyer:Amgen: Employment. Archibeque:Amgen: Employment. Sinclair:Amgen: Employment. Emkey:Amgen: Employment. Molineux:Amgen: Employment.
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Pérez, Cristina, Julia Gonzalez-Rincon, Carmen Almaraz, Soraya Curiel, Nuria Garcia, Helena Pisonero, Sagrario Gomez, et al. "A Role of JAK/STAT Pathway in Cutaneous T-Cell Lymphomas: Exploring Its Effects for Targeted Therapy." Blood 124, no. 21 (December 6, 2014): 4498. http://dx.doi.org/10.1182/blood.v124.21.4498.4498.
Анотація:
Abstract INTRODUCTION Development of targeted therapy in Cutaneous T-Cell Lymphoma (CTCL) patients still requires actionable mutated genes and deregulated pathways to be identified. We have recently published the mutational status of a number of human CTCL lesions, and found JAK/STAT signaling pathway to frequently harbor somatic mutations (Vaqué et al 2014). In this line of evidence, activating mutations in JAK kinases have been reported in human hematological malignancies (Kameda T1 2010) and may serve as indicators for targeted therapy. Therefore, we decided to analyze the mutational status of JAK/STAT pathway in a greater cohort of human CTCL patient samples and cell lines, by using massive parallel sequencing techniques, to shed light on its possible role in the pathogenesis and to uncover its potential as a new therapeutic target for this disease. To this end, we have studied the biological and molecular effects that targeted inhibition of the JAK/STAT signaling pathway, exerts in human CTCL cells, and explore its potential use as a targeted therapy. MATERIAL AND METHODS NGS: We searched for mutations in the catalytic domain of JAK and STAT genes in 39 CTCL patients using targeted NGS techniques: HaloPlex (Agilent) and sequencing in IonTorrent (LifeTech) and Illumina sequencers. Proliferation, apoptosis, cell cycle and DNA synthesis assays: CTCL cell lines were: My-La (MF), HH (MF) and HUT-78 (SS) (ECACC,Salisbury, UK). Effects in proliferation was assessed using CellTiter-Glo® Luminescent Cell Viability Assay (Promega, USA). To analyze the effects on cell survival, we evaluated early and delayed cell death provoked by FACS using FlowCellect Annexin Red Kit (EMD Millipore Corporation, USA). The distribution of cells among different phases of the cell cycle was evaluated by FACS using propidium iodide (PI, Sigma-Aldrich, USA) and Click-iT® EdU Alexa Fluor® 488 Flow Cytometry Assay Kit (Technologies-Thermo Fisher Scientific, USA) according to manufacturer’s instruction. Gene expression (GEP) studies: mRNA was extracted with Trizol and mRNA Array-based expression analysis was perfomed using a Whole Human Genome Agilent 4 × 44K v1 Oligonucleotide Microarray. RESULTS: Using our approach we found JAK/STAT pathway mutated in up to 24% of the CTCL samples. 3 mutations were found in JAK1, 5 in JAK3 and 1 in STAT5A genes. Interestingly, most of these mutations affected the tyrosine kinase domain of JAK kinases, a hotspot for activating mutations described in multiple types of human cancer. Thereafter, we decided to explore the biological effects of targeted JAK/STAT inhibition, using specific JAK inhibitors (JAKi) in preclinical CTCL models. To this end, CTCL cell lines were incubated at different time points with increasing concentrations of JAKi. These treatments inhibited JAK/STAT signaling in CTCL cells, as assessed by western-blot using P-STAT-1,-3 and -5 antibodies. Biologically, JAKi provoked a marked inhibition of cell proliferation by a mechanism impinging the control of DNA replication. This was accompanied with a modest increase in cell death. To better understand the molecular mechanisms controlled by aberrant JAK/STAT signaling, we also performed an array-based mRNA expression analysis (GEP) in HUT78 cell line (JAK1Y654F) treated at different time points (0, 0.5 and 3h) with JAKi (at a concentration of IC50). Our results showed a number of genes regulated by JAK/STAT signaling which activity has been described as T-cell activation, differentiation and proliferation (i.e. PAG1,TNF or EGR1).These genes may serve as potential indicators for therapy using JAK/STAT inhibitors or as surrogate markers for drug response. CONCLUSIONS Our results show frequent mutations affecting JAK/STAT downstream signaling in samples from patients with CTCL. Targeted inhibition of this pathway reveals an aberrant CTCL growing controlled by this signaling. Thus, these results provide evidence for the use of JAK/STAT inhibitors on the basis of a targeted massive sequencing analysis in specific cases of CTCL. Disclosures No relevant conflicts of interest to declare.
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Hindupur, Sruthi V., Sebastian C. Schmid, Jana Annika Koch, Ahmed Youssef, Eva-Maria Baur, Dongbiao Wang, Thomas Horn, et al. "STAT3/5 Inhibitors Suppress Proliferation in Bladder Cancer and Enhance Oncolytic Adenovirus Therapy." International Journal of Molecular Sciences 21, no. 3 (February 7, 2020): 1106. http://dx.doi.org/10.3390/ijms21031106.
Анотація:
The JAK-STAT signalling pathway regulates cellular processes like cell division, cell death and immune regulation. Dysregulation has been identified in solid tumours and STAT3 activation is a marker for poor outcome. The aim of this study was to explore potential therapeutic strategies by targeting this pathway in bladder cancer (BC). High STAT3 expression was detected in 51.3% from 149 patient specimens with invasive bladder cancer by immunohistochemistry. Protein expression of JAK, STAT and downstream targets were confirmed in 10 cell lines. Effects of the JAK inhibitors Ruxolitinib and BSK-805, and STAT3/5 inhibitors Stattic, Nifuroxazide and SH-4-54 were analysed by cell viability assays, immunoblotting, apoptosis and cell cycle progression. Treatment with STAT3/5 but not JAK1/2 inhibitors reduced survival, levels of phosphorylated STAT3 and Cyclin-D1 and increased apoptosis. Tumour xenografts, using the chicken chorioallantoic membrane (CAM) model responded to Stattic monotherapy. Combination of Stattic with Cisplatin, Docetaxel, Gemcitabine, Paclitaxel and CDK4/6 inhibitors showed additive effects. The combination of Stattic with the oncolytic adenovirus XVir-N-31 increased viral replication and cell lysis. Our results provide evidence that inhibitors against STAT3/5 are promising as novel mono- and combination therapy in bladder cancer.
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Barton, Beverly E., James G. Karras, Thomas F. Murphy, Arnold Barton, and Hosea F.-S. Huang. "Signal transducer and activator of transcription 3 (STAT3) activation in prostate cancer: Direct STAT3 inhibition induces apoptosis in prostate cancer lines." Molecular Cancer Therapeutics 3, no. 1 (January 1, 2004): 11–20. http://dx.doi.org/10.1158/1535-7163.11.3.1.
Анотація:
Abstract Signal transducers and activators of transcription (STAT) were originally discovered as components of cytokine signal transduction pathways. Persistent activation of one STAT, STAT3, is a common feature of prostate cancer. Activated STAT3 was found in pathology specimens obtained from prostatectomy in the cancerous areas but not in the normal margins. Because the activation of STAT3 is mediated by the action of an upstream Janus kinase (JAK) kinase, usually JAK1 or JAK2, the activation step for STAT3 might itself be a target for therapy in prostate cancer. However, the redundancy of upstream kinases may make this strategy unreliable for therapy. To develop molecular targets for prostate cancer treatment, JAK kinase and STAT3 inhibition of two prostate cancer lines were compared. DU145 and NRP-154 cells were treated with JAK kinase inhibitors, analyzed for onset of apoptosis, and measured by annexin V binding and propidium iodide uptake. Activation of caspases in the cells was determined by measuring cleaved caspase-3 following treatment. For determining the effect on mitochondrial membrane depolarization that accompanies apoptosis, the fluorescent dye JC-1 was used. STAT3 was specifically inhibited by transfecting either a dominant-negative (DN) STAT3 plasmid or antisense STAT3 oligonucleotides into the cells. To look for reduction in STAT3 levels within cells, fixed and permeabilized prostate cancer cells were stained with antibody to STAT3. We found that more than one JAK kinase is involved in STAT3 activation in prostate cancer lines. AG490 (JAK2 specific) induced apoptosis in DU145 but not in NRP-154 prostate cancer lines, whereas piceatannol (JAK1 specific) induced apoptosis in NRP-154 but not in DU145 cells. Next, we demonstrated efficacy of specific STAT3 inhibitors in prostate cancer lines. Both induction of apoptosis and reduction in intracellular STAT3 protein were observed following treatment with antisense STAT3 oligonucleotides, while transfection of a DN-STAT3 plasmid into both prostate cancer cell lines resulted in loss of viability and onset of apoptosis. We conclude that STAT3-specific inhibitors, rather than JAK kinase-specific inhibitors, should be more useful therapeutically in treating androgen-resistant prostate cancer and that STAT3 is an appropriate target in the treatment of prostate cancer.
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Westfall, Matt, Rachael E. Hawtin, Diane Longo, Michelle Cholankeril, Reena K. Vora, Michelle Atallah, Alessandra Cesano, Steven L. Allen, and Scott Z. Fields. "Functional Pathway Analysis Of JAK2 Mutated and Wild Type Myeloproliferative Neoplasms As a Tool For Patient Stratification and Therapeutic Selection." Blood 122, no. 21 (November 15, 2013): 5263. http://dx.doi.org/10.1182/blood.v122.21.5263.5263.
Анотація:
Abstract Background JAK2 signaling is essential for normal development of multiple hematopoietic cell lineages. A JAK2 (V617F) gain of function mutation has been identified in 95% of polycythemia vera (PV) and 50-60% of essential thrombocythemia (ET) patients, providing a rationale for the development of small molecule JAK2 inhibitors. Clinically, JAK2 inhibitors have been shown to be effective in controlling hyperproliferation of hematopoietic cells in PV and ET in patients with (JAK2+) and without (JAK2 WT) the JAK2 V617F mutation. This suggests that deregulation of the JAK/STAT pathway is also involved in disease pathogenesis in JAK2 negative patients. SCNP, a multiparametric flow cytometry-based assay that quantitatively measures both extracellular surface markers and changes in intracellular signaling proteins in response to modulation, was used in this study to assess JAK/STAT pathway capacity in peripheral blood mononuclear cells (PBMCs) from a small subset of PV and ET patients with and without the JAK2 mutation to assess signaling differences between and within JAK2+/WT patient subgroups and the relevance of those findings to response to in vitro JAK inhibition. Methods Cryopreserved PBMCs from 9 patients with PV/ET (3 JAK2+, 6 JAK2 WT) and 2 healthy control subjects were evaluated. Using p-STAT1, 3, and 5 as readouts, SCNP analysis quantitatively measured basal and induced JAK-STAT pathway activation after modulation with a panel of cytokines including IL-2, IL-3, IL-6, IL-10, IL-27, IFNα, IFNγ, EPO, TPO, and GM-CSF, in the presence and absence of 3 JAK inhibitors (INCB-018424, TG-101348, CP-690550) simultaneously in multiple cell subsets (monocytes, B cells, CD4+ T cells, CD4- T cells, CD34+ cells, and nRBC subsets). Results Two out of 3 JAK2+ patients, but only 2 out of 6 JAK2 WT patients, had circulating CD34+ cells comprising 8-10% of total PBMCs. Interestingly, nRBCs represented 35-73% of total PBMCs in those with a CD34+ population, but only 2-14% of total PBMCs in the patients who lacked circulating CD34+ cells suggesting a more pronounced myeloproliferative trait and/or differential homing of the affected cells in JAK2+ disease. Neither CD34+ cells nor nRBC were detected in the PBMC from the healthy control samples. Assessment of CD34+ JAK/STAT baseline and modulated signaling in the 4 samples with circulating CD34+ cells revealed functional differences between JAK2+ and WT samples. Specifically, modulated p-STAT5 responses in the two JAK2+ samples were generally lower than those observed in the WT samples, but were also distinctly different from each other. This demonstrates the presence of functional heterogeneity in otherwise molecularly defined subgroups. Importantly, examination of basal signaling levels in the presence of JAK inhibitors showed significant decrease in p-STAT5 in only one of the 2 JAK2+ samples, suggesting that the reduced modulated response observed in JAK2+/CD34+ patient samples was not due to elevated basal levels. Of note, signaling within monocytes simultaneously assessed in the same samples demonstrated a similar pattern with JAK2+/CD34+ samples having a reduced JAK2-dependent modulated signal (e.g. GM-CSF, IFNg, IL-3, IL-10) compared with both JAK2 WT/CD34+ and CD34- samples (Fig. 1A) thus suggesting the possibility of using this cell population (well represented in the peripheral blood samples) as a surrogate for CD34+ JAK/STAT signaling measurement. Finally, in vitro treatment of the CD34+ samples with different JAK inhibitors revealed different degrees of sensitivity between JAK2+ and WT samples (with the former being generally more sensitive) together with a marked heterogeneity within the JAK2+ samples themselves (Fig. 1B). Conclusions Functional pathway analysis of a small myeloproliferative neoplasm sample set identified profound heterogeneity in JAK-STAT pathway activity in circulating CD34+ cells and monocytes from JAK2+ and WT patient samples, as well as heterogeneous responses to different JAK inhibitors. Future studies in larger sample cohorts (including BM samples) are needed to assess the potential clinical utility (e.g. biology-based classification of the disease to better inform treatment decision) of these findings. Disclosures: Westfall: Nodality, Inc.: Employment, Equity Ownership. Hawtin:Nodality, Inc.: Employment, Equity Ownership. Longo:Nodality, Inc.: Employment, Equity Ownership. Atallah:Nodality, Inc.: Employment. Cesano:Nodality, Inc.: Employment, Equity Ownership.
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Fujita, M., K. Fukuda, S. Hayashi, K. Kikuchi, Y. Takashima, T. Kamenaga, T. Maeda, T. Matsubara, and R. Kuroda. "AB0089 THE ANALYSIS FOR THE INHIBITION OF ANGIOGENESIS BY JAK INHIBITOR." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 1344.2–1344. http://dx.doi.org/10.1136/annrheumdis-2020-eular.3161.
Анотація:
Background:Many blood vessels are generated in the hyperplastic synovial tissue of patients with rheumatoid arthritis (RA), and lead to chronic tissue inflammation and joint destruction [1]. Janus kinase (JAK) family consisting of JAK1, JAK2, JAK3 and tyrosine kinase 2 (TYK2) are chain receptors which phosphorylate signal transducers and activators of transcription (STAT) and mediate inflammatory diseases including RA [2]. Nowadays, several JAK inhibitors such as Tofacitinib (TOF), Baricitinib (BAR) and Peficitinib (PEF) have been developed and demonstrated to have the inhibitory effects on inflammatory arthritis [3-5]. However, there were few reports concerning their effects on angiogenesis in vitro.Objectives:The purpose of the present study is to investigate the influence of JAK inhibitors on angiogenesis of human umbilical vein endothelial cell (HUVEC) activated by vascular endothelial growth factor (VEGF).Methods:The cell line of HUVECs were used for this study. The activity of proliferation and tube formation were analyzed by counting assay and tube formation assay, respectively.In counting assay, HUVECs (5 × 104cells/ml) were seeded onto 96-well cell culture plate with 20 ng/ml VEGF including various doses (0.1µM, 1µM, 5µM) of TOF, BAR or PEF. After 48 hours incubation at 37°C in a humidified atmosphere containing 5% CO2, cell proliferation of each groups was assessed using cell counting kit. In tube formation assay, HUVECs (5 × 104cells/ml) were treated with 20ng/ml VEGF including various dose (0.1µM, 1µM, 5µM) of TOF, BAR or PEF for 00 hours, then seeded onto 48-well plate applied with Matrigel. After 24 hours incubation on Matrigel, the capillary-like tube formation of each well was photographed using phase contrast microscopy. Tube formation were quantitated by measurement of the length of branch.Results:HUVECs were activated in proliferation and tube formation by VEGF treatment. And, the proliferation and tube formation of HUVECs activated by VEGF were suppressed by All of TOF, BAR and PEF. In particular, TOF and PEF could suppress them highly.Conclusion:This study showed the inhibitory effect of JAK inhibitors on proliferation and tube formation of HUVECs activated by VEGF. In particular, the angiogenesis of HUVECs activated by VEGF was highly suppressed by TOF and PEF. VEGF is reported to regulate the angiogenesis through multi JAK-STAT signaling pathways [6]. The inhibitory effects on angiogenesis of TOF, BAR and PEF might depend on the differences in their affinity for JAKs. VEGF has been shown to a have a central involvement in the angiogenic process in RA [7]. JAK inhibitors might suppress the angiogenesis in RA synovial tissues by inhibiting VEGF signaling.References:[1]Scott DL, et al. Rheumatoid arthritis. Lancet. 2010.[2]Banerjee S, et al. JAK-STAT signaling as a target for inflammatory and autoimmune diseases: current and future prospects. Drugs. 2017.[3]William D, et al. JAK inhibitors in dermatology: the promise of a new drug class. Journal of the American Academy of Dermatology. 2017.[4]Dhillon S. Tofacitinib: A Review in Rheumatoid Arthritis. Drugs. 2017.[5]Markham A, et al. Peficitinib: First Global Approval. Drugs. 2019.[6]Zhang HY, et al. Three important components in the regeneration of the cavernous nerve: brain-derived neurotrophic factor, vascular endothelial growth factor and the JAK/STAT signaling pathway. Asian journal of andrology. 2011.[7]Paleolog EM. Angiogenesis in rheumatoid arthritis. Arthritis research. 2002.Acknowledgments:noneDisclosure of Interests:None declared
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Severin, Frezzato, Visentin, Martini, Trimarco, Carraro, Tibaldi, et al. "In Chronic Lymphocytic Leukemia the JAK2/STAT3 Pathway Is Constitutively Activated and Its Inhibition Leads to CLL Cell Death Unaffected by the Protective Bone Marrow Microenvironment." Cancers 11, no. 12 (December 4, 2019): 1939. http://dx.doi.org/10.3390/cancers11121939.
Анотація:
The bone marrow microenvironment promotes proliferation and drug resistance in chronic lymphocytic leukemia (CLL). Although ibrutinib is active in CLL, it is rarely able to clear leukemic cells protected by bone marrow mesenchymal stromal cells (BMSCs) within the marrow niche. We investigated the modulation of JAK2/STAT3 pathway in CLL by BMSCs and its targeting with AG490 (JAK2 inhibitor) or Stattic (STAT3 inhibitor). B cells collected from controls and CLL patients, were treated with medium alone, ibrutinib, JAK/Signal Transducer and Activator of Transcription (STAT) inhibitors, or both drugs, in the presence of absence of BMSCs. JAK2/STAT3 axis was evaluated by western blotting, flow cytometry, and confocal microscopy. We demonstrated that STAT3 was phosphorylated in Tyr705 in the majority of CLL patients at basal condition, and increased following co-cultures with BMSCs or IL-6. Treatment with AG490, but not Stattic, caused STAT3 and Lyn dephosphorylation, through re-activation of SHP-1, and triggered CLL apoptosis even when leukemic cells were cultured on BMSC layers. Moreover, while BMSCs hamper ibrutinib activity, the combination of ibrutinib+JAK/STAT inhibitors increase ibrutinib-mediated leukemic cell death, bypassing the pro-survival stimuli derived from BMSCs. We herein provide evidence that JAK2/STAT3 signaling might play a key role in the regulation of CLL-BMSC interactions and its inhibition enhances ibrutinib, counteracting the bone marrow niche.
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Chen, Jing, Yong Zhang, Michael N. Petrus, Wenming Xiao, Alina Nicolae, Mark Raffeld, Stefania Pittaluga, et al. "Cytokine receptor signaling is required for the survival of ALK− anaplastic large cell lymphoma, even in the presence of JAK1/STAT3 mutations." Proceedings of the National Academy of Sciences 114, no. 15 (March 29, 2017): 3975–80. http://dx.doi.org/10.1073/pnas.1700682114.
Анотація:
Activating Janus kinase (JAK) and signal transducer and activator of transcription (STAT) mutations have been discovered in many T-cell malignancies, including anaplastic lymphoma kinase (ALK)− anaplastic large cell lymphomas (ALCLs). However, such mutations occur in a minority of patients. To investigate the clinical application of targeting JAK for ALK− ALCL, we treated ALK− cell lines of various histological origins with JAK inhibitors. Interestingly, most exogenous cytokine-independent cell lines responded to JAK inhibition regardless of JAK mutation status. JAK inhibitor sensitivity correlated with the STAT3 phosphorylation status of tumor cells. Using retroviral shRNA knockdown, we have demonstrated that these JAK inhibitor-sensitive cells are dependent on both JAK1 and STAT3 for survival. JAK1 and STAT3 gain-of-function mutations were found in some, but not all, JAK inhibitor-sensitive cells. Moreover, the mutations alone cannot explain the JAK1/STAT3 dependency, given that wild-type JAK1 or STAT3 was sufficient to promote cell survival in the cells that had either JAK1or STAT3 mutations. To investigate whether other mechanisms were involved, we knocked down upstream receptors GP130 or IL-2Rγ. Knockdown of GP130 or IL-2Rγ induced cell death in selected JAK inhibitor-sensitive cells. High expression levels of cytokines, including IL-6, were demonstrated in cell lines as well as in primary ALK− ALCL tumors. Finally, ruxolitinib, a JAK1/2 inhibitor, was effective in vivo in a xenograft ALK− ALCL model. Our data suggest that cytokine receptor signaling is required for tumor cell survival in diverse forms of ALK− ALCL, even in the presence of JAK1/STAT3 mutations. Therefore, JAK inhibitor therapy might benefit patients with ALK− ALCL who are phosphorylated STAT3+.
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Vian, Laura, Mimi Lee, Giuseppe Sciumè, Nathalia Gazaniga, Stefania Dell'Orso, Stephen Brooks, and Massimo Gadina. "Elucidating the role of cytokine signaling in the homeostasis of innate immune cells with JAK inhibitors." Journal of Immunology 202, no. 1_Supplement (May 1, 2019): 181.27. http://dx.doi.org/10.4049/jimmunol.202.supp.181.27.
Анотація:
Abstract The role of the JAK/STAT pathway in the function on innate lymphoid cells (ILCs) has been mostly investigated using genetically modified animals. While elegant, these studies present with the limitation of a complete loss of ILC populations. Therefore, pharmacological manipulation of this signaling cascade with JAK inhibitors (jakinibs) is an attractive alternative strategy. Here we investigated the effect of pan- and JAK-selective inhibitors on the development and functions of murine, IFN-γ producing, ILCs and iNKT cells after oral administration of tofacitinib (JAK1; JAK3 and JAK2), ruxolitinib (JAK1; JAK2), or PF-06651600 (JAK3). We observed a significant reduction in number and function (IFN-γ production) of both splenic and hepatic NKp46+ cells with either tofacitinib or PF- 006651600. The reduction appears to correlate with the number of proliferating Ki67+ NKp46+ cells. In addition, using an iNKT-dependent mouse model of acute liver inflammation, we observed a significant decreased production of IFN-γ by liver iNKT upon tofacitinib administration. Notably, we found that PF-06651600 selectively impairs the thymic development and the proliferation of IFN-γ-producing iNKT1 cells. Overall our data suggest that the transient inhibitory activity with jakinibs has strong impact on proliferation and activity of mouse IFN- γ producing innate cells. These preliminary findings bring us one step closer to elucidating mechanisms underlying innate cells homeostasis.
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Han, Yaguang, Yan Zhang, Ying Tian, Miao Zhang, Cheng Xiang, Qiang Zhen, Jiabao Liu та ін. "The Interaction of the IFNγ/JAK/STAT1 and JAK/STAT3 Signalling Pathways in EGFR-Mutated Lung Adenocarcinoma Cells". Journal of Oncology 2022 (21 вересня 2022): 1–16. http://dx.doi.org/10.1155/2022/9016296.
Анотація:
Purpose. It was reported that the EGFR (epidermal growth factor receptor) mutation status was related to primary immune resistance in NSCLC (non-small-cell lung cancer). ICIs (immune checkpoint inhibitors) have poor efficacy and large side effects for people with EGFR mutation. EGFR mutation was considered as a sign of immune therapeutic resistance, but its underlying mechanism is difficult to be determined. Combined with our research basis, we tried to explore the possible mechanism of primary drug resistance in EFGR mutant lung adenocarcinoma through the interaction between the JAK/STAT1 and JAK/STAT3 pathway. Materials and Methods. Cell apoptosis and viability test were used to study the role of the JAK/STAT signalling pathway in lung adenocarcinoma cell survival. Western blot, RT-PCR, and flow cytometry were employed to explore the changes of expression in JAK1/2, STAT1/3, PD-L1, and related signal molecules in the case of activation or inhibition of the JAK/STAT3 signalling pathway. Results. With inhibition of inhibiting the JAK/STAT3 signalling pathway by STAT3 inhibitors, we found IFNγ-JAK-STAT1 pathway activation by IFNγ could further keep lung adenocarcinoma cells from proliferation and promote its apoptosis. The inhibition of the JAK/STAT3 pathway results in the upregulation of JAK1/2, STAT1, IRF1, IRF9, and PD-L1 and downregulation of STAT3 and SOCS1. Conclusions. The absence of the IFNγ-JAK-STAT1 signal pathway is one of the main mechanisms for the ICI endogenous resistance. The abnormal activation of the downstream JAK/STAT3 pathway in cells with EGFR mutation may have antagonistic effects on the STAT1 induced antitumor immune response, which may cause the IFNγ-JAK-STAT1 pathway to lose its function. The mechanism may result in production of the immune tolerance of the EGFR mutant, which promotes immune escape.