Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

BCR-ABL is a causative tyrosine kinase (TK) of chronic myelogenous leukemia (CML). In CML patients, although myeloid cells are remarkably proliferating, erythroid cells are rather decreased and anemia is commonly observed. This phenotype is quite different from that observed in polycythemia vera (PV) caused by JAK2 V617F, whereas both oncogenic TKs activate common downstream molecules at the level of hematopoietic stem cells (HSCs). To clarify this mechanism, we investigated the effects of BCR-ABL and JAK2 V617F on erythropoiesis. Enforced expression of BCR-ABL but not of JAK2 V617F in murine LSK (Lineage(-)Sca-1(hi)CD117(hi)) cells inhibited the development of erythroid cells. Among several signaling molecules downstream of BCR-ABL, an active mutant of N-Ras (N-RasE12) but not of STAT5 or phosphatidylinositol 3-kinase (PI3-K) inhibited erythropoiesis, while N-RasE12 enhanced the development of myeloid cells. BCR-ABL activated Ras signal more intensely than JAK2 V617F, and inhibition of Ras by manumycin A, a farnesyltransferase inhibitor, ameliorated erythroid colony formation of CML cells. As for the mechanisms of Ras-induced suppression of erythropoiesis, we found that GATA-1, an erythroid-specific transcription factor, blocked Ras-mediated mitogenic signaling at the level of MEK through the direct interaction. Furthermore, enforced expression of N-RasE12 in LSK cells derived from p53-, p16(INK4a)/p19(ARF)-, and p21(CIP1/WAF1)-null/wild-type mice revealed that suppressed erythroid cell growth by N-RasE12 was restored only by p21(CIP1/WAF1) deficiency, indicating that a cyclin-dependent kinase (CDK) inhibitor, p21(CIP1/WAF1), plays crucial roles in Ras-induced suppression of erythropoiesis. These data would, at least partly, explain why respective oncogenic TKs cause different disease phenotypes.
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PMID:BCR-ABL but not JAK2 V617F inhibits erythropoiesis through the Ras signal by inducing p21CIP1/WAF1. 2066 70

The four major entities that form the group of myeloproliferative neoplasms (MPN) are BCR-ABL positive chronic myeloid leukaemia (CML), chronic idiopathic myelofibrosis (CIMF), essential thrombocythemia (ET) and polycythemia vera (PV). All four are clonal diseases of the haematopoietic stem or precursor cell, they are of a chronic nature and potentially aggravate to myelofibrosis or transform into acute leukaemia. Several strategies are pursued in the treatment of MPN. On the one hand, targeted therapies such as tyrosine kinase inhibitors (imatinib, dasatinib, nilotinib) and JAK2-inhibitors are adopted in MPN as well as rather unspecific treatment with interferon-alpha and with the newer group of immunomodulatory drugs (IMIDs). On the other hand, cellular immunotherapeutical options as allogeneic haematopoietic stem cell transplantation (HSCT) and donor lymphocyte infusion (DLI) are exerted in patients with MPN. Evidence resulting from graft-versus-leukaemia (GvL) effect was the key to develop more specific immunotherapies for patients with haematologic malignancies. In this context, CML is a model for immunotherapeutic approaches, and therefore, vaccination trials using peptides derived from leukaemia-associated antigens (LAAs) to stimulate specific T cells are currently under investigation. But also in BCR-ABL-negative MPNs, antigens have been identified and immunomodulatory treatment strategies have been performed. All of the current immunotherapeutical options in patients with MPN will be discussed throughout this review.
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PMID:Immunotherapy for myeloproliferative neoplasms (MPN). 2106 47

Neutrophil gelatinaase-associated lipocalin (NGAL) is a glycoprotein bound with matrix metalloproteinase-9 (MMP-9) in human neutrophils, and elevated tissue NGAL expression has been documented in different infectious and inflammatory conditions. Recent evidence suggests that NGAL expression is induced in many types of human cancer. Moreover, NGAL is required for BCR-ABL-induced tumorigenesis. The aim of the present study was to measure serum levels of NGAL in patients with essential thrombocythemia (ET) and polycythemia vera (PV). We also evaluated NGAL levels in patients with ET and PV with and without thrombotic events, to explore a possible correlation of NGAL with platelet and leukocyte activation, and in patients with sepsis. Serum NGAL levels in the study population were significantly higher than in healthy adults and in subjects with sepsis. A correlation between NGAL and the number of white cells and neutrophils was found in patients with PV and ET. NGAL serum levels were not different depending on the presence or not of the JAK2 mutation, and a mutant allele dosage effect was not observed for NGAL levels. Patients with PV and ET with thrombosis did not have significantly higher levels of NGAL. We were unable to demonstrate a significant association between serum NGAL levels and CD11b or CD62 expression. In conclusion, our study reports evidence demonstrating that increased levels of NGAL appear to be a characteristic of patients with PV and ET.
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PMID:Increased serum levels of neutrophil gelatinase-associated lipocalin in patients with essential thrombocythemia and polycythemia vera. 2226 71

Although the Janus family of kinases (JAK1, JAK2, JAK3, and TYK2) has been extensively characterized and investigated, the role of Janus kinase activation in the pathogenesis and therapy of human malignancies was not fully appreciated until recently when multiple studies identified a recurrent somatic mutation in the JAK2 tyrosine kinase (JAK2V617F) in the majority of patients with BCR-ABL-negative myeloproliferative neoplasms (MPN), polycythemia vera, essential thrombocytosis, and primary myelofibrosis. Other mutations that activate the JAK-STAT signaling pathway have since been identified in JAK2V617F-negative MPN patients and in a subset of patients with acute myeloid leukemia and acute lymphoid leukemia. In addition, dysregulated JAK-STAT signaling has been implicated in the pathogenesis of a spectrum of epithelial neoplasms. In this chapter, we will review the recent studies that identified genetic alterations that activate JAK signaling in different malignancies, and discuss the recent efforts aimed at developing small-molecule inhibitors of JAK kinase activity for the treatment of MPNs and other malignancies.
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PMID:JAK-mutant myeloproliferative neoplasms. 2182 28

This study was aimed to investigate the incidence of JAK2V617F mutation in BCR-ABL negative patients with myeloproliferative disorders (MPD) and its relation with clinical characteristics of MPD. The sensitive and specific test for JAK2V617F mutation was established for improving diagnosis level in Gansu province. 47 BCR/ABL negative MPD patients and 12 healthy people were enrolled in this study. Allele specific polymerase chain reaction (AS-PCR) was used to amplify the exon 12 of JAK2 gene which harbours V617F mutation. The PCR products were identified by DNA sequencing. And its relation with clinical characteristics of MPD was analyzed also. The results indicated that the incidence of JAK2V617F positive mutation in 47 patients with BCR-ABL negative MPD was 74.5 % (35/47), including 83.9 %(26/31) in patients with polycythemia vera (PV), 60 % (9/15) in patients with essential thrombocythemia (ET), only in one patient with idiopathic myelofibrosis (IMF). In PV group, the patients with JAK2V617F positive mutation had higher counts of WBC and Plt than patients with JAK2V617F negative mutation. In ET group, the patients with JAK2V617F positive mutation had higher WBC count and Hb level than those in the patients with JAK2V617F negative mutation with tendency of suffering from complications such as hepatosplenomegaly, haemorrhage and thrombosis. It is concluded that JAK2V617F mutation is more frequent in BCR-ABL negative patients with MPD, the AS-PCR method is sensitive and specific for detection of the mutation and may successfully use in clinical examination.
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PMID:[JAK2V617F mutation in the patients with myeloproliferative disorder and its relation with clinical characteristics]. 2186 14

The BCR-ABL-negative myeloproliferative neoplasms (MPNs) include essential thrombocythemia, polycythemia vera, and primary myelofibrosis. Historically, complex biochemical alterations defining these heterogeneously distinct malignancies have remained elusive and constrained available therapy options. The discovery of Janus kinase (JAK) mutations collectively present in BCR-ABL-negative MPNs has led to a resurgence of medical interest in JAK-STAT targeted treatment modalities, as well as provided a unique platform for inhibiting symptom-directing proinflammatory cytokines. INCB018424, CYT387, SB1518, and TG101348 are among the most propitious JAK2 inhibitors under investigation, providing substantial improvement in constitutional symptoms, transfusion-dependent cytopenias, and reduction in spleen size. Despite their attributes, evidence of complete or partial remission has yet to be observed with therapy. Many uncertainties surrounding the full clinical potential of JAK2 inhibitors persist. Treatment guidelines addressing optimal stages for drug implementation, ideal dosing parameters and criteria for medication continuation/withdrawal may effectively resolve these ongoing concerns and provide advancements in the morbidity and mortality of these multifaceted disease processes.
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PMID:JAK2 inhibitors and their impact in myeloproliferative neoplasms. 2250

BCR-ABL-negative myeloproliferative neoplasms (MPNs) are most frequently characterized by the JAK2V617F gain-of-function mutation, but several studies showed that JAK2V617F may not be the initiating event in MPN development, and recent publications indicate that additional alterations such as chromatin modification and microRNA (miRNA) deregulation may have an important role in MPN pathogenesis. Here we report that 61 miRNAs were significantly deregulated in CD34+ cells from MPN patients compared with controls (P<0.01). Global miRNA analysis also revealed that polycythemia vera (JAKV617F) and essential thrombocythemia (JAK2 wild type) patients have significantly different miRNA expression profiles from each other. Among the deregulated miRNAs, expression of miR-134, -214 and -433 was not affected by changes in JAK2 activity, suggesting that additional signaling pathways are responsible for the deregulation of these miRNAs in MPN. Despite its upregulation in MPN CD34+ and during normal erythropoiesis, both overexpression and knockdown studies suggest that miR-433 negatively regulates CD34+ proliferation and differentiation ex vivo. Its novel target GBP2 is downregulated during normal erythropoiesis and regulates proliferation and erythroid differentiation in TF-1 cells, indicating that miR-433 negatively regulates hematopoietic cell proliferation and erythropoiesis by directly targeting GBP2.
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PMID:miR-433 is aberrantly expressed in myeloproliferative neoplasms and suppresses hematopoietic cell growth and differentiation. 2286 58

Myeloproliferative neoplasms (chronic myeloproliferative disorders according to former nomenclature) comprise chronic myeloid leukemia, polycythemia vera, essential thrombocythemia, primary myelofibrosis, chronic eosinophilic leukemia, chronic neutrophilic leukemia and systemic mastocytosis. All disorders have excessive proliferation of one or more hematopoietic lineages in common and progress with different probability to blast crisis or fibrosis. A further common feature is provided by the activating mutation of tyrosin kinases and associated pathways of signal transduction (BCR-ABL, JAK2(V617F), MPL(W515L/K), KIT(D816V) and FIP1L1-PDGFRA) causative for the abnormal proliferation. With regard to diagnosis and therapy these mutations are of utmost importance because they enable the exclusion of reactive processes, contribute with varying specificity to subtyping of MPN and are at least partly sensitive to targeted therapy. The molecular mechanisms of blastic and fibrotic progression are not yet understood.
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PMID:[Myeloproliferative neoplasms: histopathological and molecular pathological diagnosis]. 2308 94

The classic BCR-ABL-negative myeloproliferative neoplasms (MPNs) which include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) are among the most frequent hematologic neoplasms. Because of their relatively smooth clinical course, it is likely that many of these MPNs actually go undetected. Considering the high prevalence of iron, folic-acid, and vitamin B(12) deficiencies in developing countries, their coexistence with MPN can be expected frequently. In such situations where both disorders coexist, MPN is often overlooked. This causes considerable diagnostic delay. In this paper, two cases of PMF and one case of PV where the diagnosis of MPN was delayed for about 3 years are discussed. Presence of concomitant vitamin B(12), folate, and iron deficiencies perhaps camouflaged the underlying MPN. Bearing in mind the possibility of MPN, even in the setting of apparent nutritional deficiency and performing a bone marrow evaluation, is the crucial step in unveiling the hidden MPN.
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PMID:Myeloid neoplasms in the guise of nutritional deficiency. 2322 77

The classical BCR-ABL negative myeloproliferative neoplasms (MPN) polycythemia vera, essential thrombocythemia, and primary myelofibrosis are clonal hematopoietic disorders characterized by excessive production of terminally differentiated myeloid cells. In MPN patients, the disease can progress to secondary myelofibrosis or acute myeloid leukemia. Clonal hematopoiesis, disease phenotype, and progression are caused by somatically acquired genetic lesions of genes involved in cytokine signaling, RNA splicing, as well as epigenetic regulation. This review provides an overview of point mutations and cytogenetic lesions associated with MPN and addresses the role of these somatic lesions in MPN disease progression.
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PMID:Genetic and epigenetic alterations of myeloproliferative disorders. 2323 54


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