Accumulation of JAK activation loop phosphorylation is linked to type I JAK inhibitor withdrawal syndrome in myelofibrosis

Tvorogov, Denis; Thomas, Daniel; Liau, Nicholas P. D.; Dottore, Mara; Barry, Emma F.; Lathi, Maya; Kan, Winnie L.; Hercus, Timothy R.; Stomski, Frank C.; Hughes, Timothy P.; Tergaonkar, Vinay; Parker, Michael W.; Ross, David M.; Majeti, Ravindra; Babon, Jeffrey J.; Lopez, Angel F.

doi:10.1126/sciadv.aat3834

Cited by 43 publications

(73 citation statements)

References 28 publications

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“…Recently, Tvorogov et al showed that ruxolitinib induces dose-dependent pJAK2, which can cause life-threatening cytokine-rebound syndrome (due to re-activation of STAT) when the drug is withdrawn [49]. Again, the effect was not apparent when the JAK2 V617F expressing cells were treated with type II inhibitor.…”

Section: Discussionmentioning

confidence: 99%

Characterization of JAK1 Pseudokinase Domain in Cytokine Signaling

Raivola

Haikarainen

Silvennoinen

2019

Cancers

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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.

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Section: Discussionmentioning

confidence: 99%

Characterization of JAK1 Pseudokinase Domain in Cytokine Signaling

Raivola

Haikarainen

Silvennoinen

2019

Cancers

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“…However, type 1 JAK inhibition prevented dephosphorylation and ubiquitination of JAK2, leading to progressive accumulation of an activation loop phosphorylated pool. The phosphorylated pool is rapidly depleted on JAK inhibitor cessation, accounting for the rapid recrudescence of the clinical syndrome known as JAK inhibitor withdrawal syndrome [156].…”

Section: Jak Inhibitorsmentioning

confidence: 99%

“…Type 2 JAK2 inhibition occurs when the inhibitor binds to the inactive state at a hydrophobic pocket adjacent to the ATP binding site uncovered by conformational change of the activation loop leading to stabilization of inactive JAK2 [155,157,158]. There is an absence of phosphorylation accumulation and hence no washout seen with type 2 inhibitor withdrawal in vitro [156]. JAK2 inhibitors currently in clinical practice and clinical trials include type 1 inhibitors ruxolitinib, fedratinib, momelotinib and pacritinib [158,159].…”

Section: Jak Inhibitorsmentioning

confidence: 99%

MPN: The Molecular Drivers of Disease Initiation, Progression and Transformation and their Effect on Treatment

Grabek

Straube

Bywater

et al. 2020

Cells

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Myeloproliferative neoplasms (MPNs) constitute a group of disorders identified by an overproduction of cells derived from myeloid lineage. The majority of MPNs have an identifiable driver mutation responsible for cytokine-independent proliferative signalling. The acquisition of coexisting mutations in chromatin modifiers, spliceosome complex components, DNA methylation modifiers, tumour suppressors and transcriptional regulators have been identified as major pathways for disease progression and leukemic transformation. They also confer different sensitivities to therapeutic options. This review will explore the molecular basis of MPN pathogenesis and specifically examine the impact of coexisting mutations on disease biology and therapeutic options.

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“…Inhibitor binding promotes PKB membrane localisation, regulatory site phosphorylation (T308 and S473) by PDK1 and mTORC2, and acquisition of a phosphatase-resistant conformation; consequently, when the inhibitor is removed the 'primed' kinase is fully active [69,6]. Other kinases that undergo 'priming paradoxical activation' (Figure 2) include PKC [70], PKD [71], AMPK [72] and JAK2 [73,74,75]. This mechanism can have severe physiological consequences; for example, a life-threatening cytokine-rebound syndrome occurs when the JAK2 inhibitor, ruxolitinib, is withdrawn too quickly and this is due to priming paradoxical activation of JAK2 [73,74,75].…”

Section: Paradoxical Signalling Induced By Erk5 Kinase Inhibitors Difmentioning

confidence: 99%

Small molecule ERK5 kinase inhibitors paradoxically activate ERK5 signalling: be careful what you wish for…

Cook

Tucker

Lochhead

2020

Biochemical Society Transactions

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ERK5 is a protein kinase that also contains a nuclear localisation signal and a transcriptional transactivation domain. Inhibition of ERK5 has therapeutic potential in cancer and inflammation and this has prompted the development of ERK5 kinase inhibitors (ERK5i). However, few ERK5i programmes have taken account of the ERK5 transactivation domain. We have recently shown that the binding of small molecule ERK5i to the ERK5 kinase domain stimulates nuclear localisation and paradoxical activation of its transactivation domain. Other kinase inhibitors paradoxically activate their intended kinase target, in some cases leading to severe physiological consequences highlighting the importance of mitigating these effects. Here, we review the assays used to monitor ERK5 activities (kinase and transcriptional) in cells, the challenges faced in development of small molecule inhibitors to the ERK5 pathway, and classify the molecular mechanisms of paradoxical activation of protein kinases by kinase inhibitors.

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Accumulation of JAK activation loop phosphorylation is linked to type I JAK inhibitor withdrawal syndrome in myelofibrosis

Abstract: Pathological drug withdrawal syndrome is linked to accumulation of JAK2 phosphorylation in V617F myelofibrosis.

Cited by 43 publications

References 28 publications

Characterization of JAK1 Pseudokinase Domain in Cytokine Signaling

Characterization of JAK1 Pseudokinase Domain in Cytokine Signaling

MPN: The Molecular Drivers of Disease Initiation, Progression and Transformation and their Effect on Treatment

Small molecule ERK5 kinase inhibitors paradoxically activate ERK5 signalling: be careful what you wish for…

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