Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.2 (focal adhesion kinase)
44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Approximately one-half of the cases of Budd-Chiari syndrome (BCS) are caused by bcr/abl negative chronic myeloproliferative disorders (CMPDs). Furthermore, a mutation in the Janus kinase protein (JAK2-V617F) is detected in half of the patients with BCS. However, whether the JAK2 mutation is the primary event leading to CMPDs and BCS is controversial. We present a report concerning a young woman who suffered from BCS prior to the onset of CMPDs. Analysis of X-chromosome inactivation patterns in this patient, using the human androgen receptor gene demonstrated monoclonal haematopoiesis in her granulocytes. In contrast, she had a low burden of a JAK2-V617F mutation positive clone among granulocyte populations. These results suggest that the JAK2-V617F mutation occurs after the onset of monoclonal haematopoiesis; thus the V617F mutation of JAK2 may not be the primary event in the induction of BCS.
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PMID:Low burden of a JAK2-V617F mutated clone in monoclonal haematopoiesis in a Japanese woman with Budd-Chiari syndrome. 1930 56

ETV6/ABL is a rare gene rearrangement that has rarely been detected in Philadelphia-negative chronic myeloproliferative disorders (C-MPD) and found to have tyrosine kinase activity similar to the BCR/ABL fusion protein. We describe a case of a 61-year-old female with a C-MPD associated with an ETV6/ABL gene rearrangement. She achieved complete cytogenetic remission on imatinib 400mg daily for 17 months, but then developed morphologic and cytogenetic relapse. After starting nilotinib 400mg orally twice daily, she achieved CCyR at 3, 6, and 11 months, suggesting that second-generation TKIs can result in favorable responses in patients with ETV6/ABL rearrangement who relapse after imatinib.
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PMID:Myeloproliferative disorder with eosinophilia and ETV6-ABL gene rearrangement: efficacy of second-generation tyrosine kinase inhibitors. 1939 93

The chronic myeloproliferative disorders, polycythemia vera, essential thrombocythemia, and primary myelofibrosis, are clonal stem cell disorders that occur at a low frequency and mimic not only each other clinically, but also many benign and malignant hematopoietic disorders as well. The discovery that many patients with polycythemia vera, essential thrombocythemia, and primary myelofibrosis express a mutation in the Janus Kinase 2 gene (JAK2 V617F), a kinase essential for the normal development of erythrocytes, granulocytes, and platelets, provided a molecular explanation for the unregulated hematopoiesis typical of these disorders, a diagnostic test that distinguishes them from other types of myeloproliferative disorders, and an opportunity to develop targeted therapy that could potentially avoid the toxicities associated with the conventional chemotherapeutic agents currently employed in their treatment. In this review, we discuss the molecular basis of polycythemia vera, essential thrombocythemia, and primary myelofibrosis, their diagnosis and their management in the context of the JAK2 V617F mutation.
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PMID:The diagnosis and management of polycythemia vera, essential thrombocythemia, and primary myelofibrosis in the JAK2 V617F era. 1952 23

Recently, mutations in the gene of Janus kinase 2 (Jak2) were discovered in patients suffering from chronic myeloproliferative disorders (MPD) and leukemia. As suppressors of cytokine signaling (SOCS) proteins are potent feedback inhibitors of Jak-mediated signaling, we investigated their role in signal transduction through constitutively active Jak2 mutants. We selected two mutants, Jak2-V617F and Jak2-K539L, found in patients with MPDs and Jak2-T875N identified in acute megakaryoblastic leukemia. We found SOCS family members to be induced through Jak2-V617F in human leukemia cell lines expressing the mutant allele and in stable HEK transfectants inducibly expressing constitutively active Jak2 mutants. SOCS proteins were recruited to the membrane and bound to the constitutively active Jaks. In contrast to wild-type Jak2, the mutant proteins were constitutively ubiquitinated and degraded through the proteasome. Taken together, we show a SOCS-mediated downregulation of the constitutively active, disease-associated mutant Jak2 proteins. Furthermore, a threshold level of mutant Jak expression has to be overcome to allow full cytokine-independent constitutive activation of signaling proteins, which may explain progression to homozygocity in MPDs as well as gene amplification in severe phenotypes and leukemia.
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PMID:SOCS-mediated downregulation of mutant Jak2 (V617F, T875N and K539L) counteracts cytokine-independent signaling. 1954 16

Two putative types of circulating endothelial progenitor cells have been recently identified in vitro: (1) endothelial colony-forming cell (ECFC) and (2) colony-forming unit-endothelial cell (CFU-EC). Only the former is now recognized to belong to endothelial lineage. We have used the ECFC and CFU-EC assays to readdress the issue of the clonal relation between endothelial progenitor cells and hematopoietic stem cells in patients with Philadelphia-positive and Philadelphia-negative chronic myeloproliferative disorders. Both ECFCs and CFU-ECs were cultured from peripheral blood mononuclear cells, and either BCR-ABL rearrangement or JAK2-V617F mutation were assessed in both types of endothelial colonies. We found that ECFCs lack the disease-specific markers, which are otherwise present in CFU-ECs, thus reinforcing the concept that the latter belongs to the hematopoietic lineage, and showing that in chronic myeloproliferative disorders the cell that gives rise to circulating ECFC has a distinct origin from the cell of the hematopoietic malignant clone.
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PMID:Endothelial colony-forming cells from patients with chronic myeloproliferative disorders lack the disease-specific molecular clonality marker. 1962 7

The chronic myeloproliferative disorders (MPDs) include the spectrum of clonal hematopoietic stem cell disorders whose phenotype derive from the primary cell expanded in a proliferative state. The MPDs (which include polycythemia vera (PV), essential thrombocythemia (ET), chronic eosinophilic leukemia (CEL), primary myelofibrosis (PMF), chronic myelomonocytic leukemia (CMML), and systemic mast cell disease (SMCD)) exclude chronic myeloid leukemia (CML) because of the pathognomic importance of the BCR-ABL translocation for the diagnosis and treatment of this disorder with imatinib mesylate. Empiric use of imatinib mesylate against the spectrum of BCR-ABL negative MPDs has had mixed results. Significant benefits were obtained when empiric use of imatinib in CEL and CMML led to significant clinical benefit and the discovery of the role of rearrangements of the platelet derived growth factor receptor -alpha (PDGFRa-FIP1L1 in CEL and SMCD) and -beta (PDGFRb through TEL-PDGFRb) for CMML). Empiric use of imatinib in PMF has been disappointing, and in PV quite modest. Although next generation Abelson kinase inhibitors such as dasatinib or nilotinib may expand the role for these agents in MPDs, targeted inhibition of the mutant kinase JAK2(V617F) is more likely to make significant therapeutic gains in the classic MPDs of PV, ET, and PMF.
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PMID:Imatinib and tyrosine kinase inhibition, in the management of BCR-ABL negative myeloproliferative disorders. 1970 23

Reliable epidemiological information on chronic myeloproliferative disorders (CMPDs), notably Philadelphia (Ph)/BCR-ABL-positive chronic myeloid leukaemia (CML), is rare. Incidence rates vary from 0.6 to 2.0 cases per 100 000 inhabitants, increase with age and are higher in men than in women. Geographic and/or ethnic variations might contribute to the variability of incidences among registries. Prevalence rate has increased by use of tyrosine kinase inhibitors. In daily clinical practice, some CML management areas are not in line with the current recommendations. Problematic areas are sub-optimal timing of treatment decisions under monitoring, and unawareness of new molecular monitoring techniques and of beneficial new tyrosine kinase inhibitors. Median age differs between cancer registries and clinical trials by 10-20 years. Reports of clinical studies underestimate the true age of the CML population. Elderly CML patients are underrepresented in clinical studies and thus have a reduced access to investigational therapies.
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PMID:Epidemiology of chronic myeloid leukaemia (CML). 1995 81

Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic myeloproliferative disorders characterized by an increased incidence of thrombo-hemorrhagic complications. The acquired somatic Janus kinase 2 (JAK2) V617F mutation is present in the majority of PV and ET patients. Because aberrant protein Tyr-phosphorylation has been associated with hematopoietic malignancies, the activity of the tyrosine kinases Src and JAK2 was analyzed in resting and thrombin-stimulated platelets from 13 PV and 42 ET patients. JAK2 was found inactive in healthy and pathological resting cells regardless of the V617F mutation. In addition, Src was inactive in all resting platelets, but in the pathological specimens it was present in a preactivated conformation as a consequence of anomalous dephosphorylation of its inhibitory phospho-Tyr527 residue, likely mediated by Src homology-2 domain-containing protein Tyr-phosphatase-2 (SHP-2), whose constitutive activity correlated with its recruitment to Src. Low thrombin concentration triggered a more rapid Src-signaling activation, higher [Ca(2+)](c) increase, and aggregation in pathological platelets compared with controls. Thrombin-induced Src activation preceded JAK2 activation, which occurred simultaneously in normal and pathological platelets. Our results indicate that a constitutive Src kinase preactivation is implicated in platelet hypersensitivity and likely involved, at least partially, in the functional abnormalities of PV and ET platelets.
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PMID:Src tyrosine kinase preactivation is associated with platelet hypersensitivity in essential thrombocythemia and polycythemia vera. 1996 50

JAK2 is a target of high interest in chronic myeloproliferative disorders drug research. Starting from a screening hit, two new JAK2 inhibitor chemotypes were designed by scaffold morphing. The prototype compounds of these new series showed nanomolar inhibition of the kinase.
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PMID:Design of two new chemotypes for inhibiting the Janus kinase 2 by scaffold morphing. 2017 18

A common somatic point mutation has recently been identified in the Janus kinase 2 (JAK2) gene in virtually all cases of polycythemia vera and in a majority of patients with essential thrombocythemia and idiopathic myelofibrosis. This common mutation in the pseudokinase autoinhibitory domain of the enzyme results in constitutive tyrosine kinase activation, which in turn leads to cytokine hypersensitivity and factor independence in factor-dependent cell lines, and causes polycythemia in mice. This discovery has led to greater understanding of the molecular pathogenesis of the chronic myeloproliferative disorders, which may translate into targeted therapy.
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PMID:The JAK2(V617F) tyrosine kinase mutation in myeloproliferative disorders: Summary of published literature and a perspective. 2042 35


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