ABSTRACT
BACKGROUND: Philadelphia negative myeloproliferative neoplasms (Ph-MPN) are clonal disorders whose pathogenesis has been elucidated in recent years, creating diagnostic and prognostic algorithms. AIM: To study JAK2, CALR y MPL gene mutations in patients with Ph-MPN. MATERIALS AND METHODS: Descriptive cross-sectional observational study of patients with MPN (2015-2019), reviewing clinical, demographic and laboratory data. JAK2, CALR and MPL gene mutations were analyzed by RT-PCR. Results: We studied 72 patients. Fifty percent had essential thrombocythemia (ET), 26.4% had polycythemia vera (PV) and 23.6% had primary myelofibrosis (PM). Bone marrow biopsy was available in 76.5%. At diagnosis, the mean age was 65.5 years and 61% were symptomatic. A thrombotic event was the most frequent problem in 20% and 25% had splenomegaly. There were statistically significant differences in hematological parameters between the different MPNs. JAK2 V617F mutation was detected in 61.1%. Only 19 JAK2 V617F negative patients were available for CALR and MPL mutation studies, identifying 10 triple negative cases. Kaplan Meier curves showed a median survival of 88 months, being similar in the three MPNs. Causes of death in 20 patients were thrombotic complications in 30%, disease progression in 25%, infection in 20%, other neoplasms in 15% and other causes in 10%. CONCLUSIONS: The presentation and frequency of JAK2 V617F, CALR and MPL mutations in our cohort was similar to those reported in other studies for ET and PM. JAK2 V617F mutation was lower for PV. No significant differences between the three MPNs were observed for overall survival. We could not assess the prognostic value of the mutations.
Subject(s)
Humans , Aged, 80 and over , Polycythemia Vera/genetics , Thrombocythemia, Essential/diagnosis , Thrombocythemia, Essential/genetics , Myeloproliferative Disorders/genetics , Chile , Cross-Sectional Studies , Hospitals, Public , MutationABSTRACT
BACKGROUND: Philadelphia-negative myeloproliferative neoplasms (Ph-MPN) are chronic hematological disorders characterized by the overproduction of one or more mature myeloid blood cell lineages. Classical Ph-MPN are polycythemia vera (PV), essential thrombocytopenia (ET) and primary myelofibrosis (PMF). AIM: To assess the epidemiological, clinical and diagnostic characteristics of Ph-MPN in Chile. Material and Methods: Retrospective review of medical records of all patients referred as MPN from 2012 to 2017. Patients with (9;21) translocation were excluded. RESULTS: Data of 462 cases with a median age of 69 years from 10 public hospitals was reviewed. ET was the most frequently Ph-MNP found. The incidence of Ph-MPN was 1.5 x 100.000 cases. The JAK2 V617F mutation study was performed in 96% of patients and only 30% had a bone marrow biopsy. Thrombotic events were observed in 29% of patients. Bleeding events were observed in 7%. Five-year overall survival was 87%. Conclusions: ET is the most frequent Ph-MPN. The mean incidence was lower than reported in the literature, in part because of a sub diagnosis.
ABSTRACT
Trombose essencial é uma das doenças mieloproliferativas crônicas, rara e de etiologia ainda desconhecida, mas que apresenta risco alto de eventos trombóticos e/ou hemorrágicos, uma vez que acomete as células megacariocíticas e, consequentemente, as plaquetas. O objetivo deste trabalho foi realizar uma revisão das publicações sobre o tema abordado. O estudo caracteriza-se como revisão bibliográfica de artigos das bases de dados da Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs), National Library of Medicine (PubMed), Scientific Electronic Library Online (SciELO) e Google acadêmico. Foram incluídos artigos disponíveis e em qualquer idioma de publicação, com a finalidade de aumentar o referencial teórico. Posteriormente à seleção e análise dos artigos, foram encontrados alguns pontos em comum, como a dificuldade em se diagnosticar a doença. De acordo com os estudos, a maioria dos doentes é assintomática, mas pode apresentar desde eventos trombóticos até mesmo embolia pulmonar. Atualmente, o tema vem crescendo, principalmente abordando técnicas moleculares mais específicas para a descoberta da doença em seu estágio inicial. A análise dos artigos demonstrou a dificuldade do diagnóstico da trombose essencial, sendo a sua identificação crucial nos estágios iniciais.
Essential thrombosis is one of the chronic myeloproliferative diseases, rare and of unknown etiology, but which presents a high risk of thrombotic and / or hemorrhagic events. Once it attacks the megakaryocytic cells and consequently the platelets. The objective of this work is to review the publications on the subject. The study is characterized as a bibliographical review of articles from the Latin American and Caribbean Literature in Health Sciences (LILACS), National Library of Medicine (PubMed), Scientific Electronic Library Online (SciELO) and Google Acadêmico. Articles were included and in any language of publication, in order to increase the theoretical reference. Subsequent to the selection and analysis of the articles, some common points were found such as the difficulty in diagnosing the disease. According to the studies, the majority of patients are asymptomatic but may present from thrombotic events to even pulmonary embolism. Currently, the topic has been growing, mainly addressing molecular techniques more specific to the discovery of the disease in its initial stage. The analysis of the articles demonstrated the difficulty of diagnosing essential thrombosis, which is crucial in the initial stages.
Subject(s)
Thrombocytosis , Janus Kinase 2 , Thrombocythemia, EssentialABSTRACT
Myelodysplastic syndrome (MDS) cases comprise a heterogeneous group of hematological disorders that are characterized by impaired hematopoiesis, with cytopenias of different grades and risk of developing acute myeloid leukemia. MDS may rarely be associated with thrombocytosis. In such cases, myelodysplasia and myeloproliferative disorders may overlap, making correct diagnosis difficult. We herein describe a case of MDS with thrombocytosis, Janus kinase 2 gene mutation-positive and Perls' staining-negative, which was initially classified as essential thrombocythemia (ET). This case highlights that MDS may be misdiagnosed as ET and inappropriate treatment may be initiated. Therefore, it is crucial to carefully combine all available data on morphology and immunophenotyping, and to perform the necessary molecular, cytogenetic and molecular cytogenetic analyses, in order to correctly diagnose this disease.
ABSTRACT
Primary myelofibrosis is a Philadelphia-negative myeloproliferative neoplasm characterized by clonal myeloid expansion, followed by progressive fibrous connective tissue deposition in the bone marrow, resulting in bone marrow failure. Clonal evolution can also occur, with an increased risk of transformation to acute myeloid leukemia. In addition, disabling constitutional symptoms secondary to the high circulating levels of proinflammatory cytokines and hepatosplenomegaly frequently impair quality of life. Herein the main current treatment options for primary myelofibrosis patients are discussed, contemplating disease-modifying therapeutics in addition to palliative measures, in an individualized patient-based approach.
ABSTRACT
BACKGROUND: Myeloproliferative neoplasms are Philadelphia chromosome-negative diseases characterized by hyperproliferation of mature myeloid cells, associated or not with the Janus kinase 2 tyrosine kinase mutation, JAK2V617F. As there is no curative therapy, researchers have been investigating new drugs to treat myeloproliferative neoplasms, including l-amino acid oxidase from Calloselasma rhodostoma snake venom (CR-LAAO), which is a toxin capable of eliciting apoptosis in several tumor cell lines. OBJECTIVE: To evaluate the effects of l-amino acid oxidase from C. rhodostoma snake venom in the apoptotic machinery of JAK2-mutated cell lines. METHODS: The HEL 92.1.7 and SET-2 cell lines were cultured with l-amino acid oxidase and catalase for 12 h at 37 °C in 5% carbon dioxide. The cell viability was assessed by the multi-table tournament method, the level of apoptosis was measured by flow cytometry, and the expression of cysteine-dependent aspartate-specific proteases and cleaved Poly(ADP-ribose) polymerase were analyzed by Western blotting. RESULTS: l-Amino acid oxidase from C. rhodostoma snake venom was cytotoxic to HEL 92.1.7 and SET-2 cells (50% inhibitory concentration = 0.15 µg/mL and 1.5 µg/mL, respectively) and induced apoptosis in a concentration-dependent manner. Cell treatment with catalase mitigated the l-amino acid oxidase toxicity, indicating that hydrogen peroxide is a key component of its cytotoxic effect.The activated caspases 3 and 8 expression and cleaved PARP in HEL 92.1.7 and SET-2 cells confirmed the apoptosis activation by CR-LAAO. CONCLUSIONS: l-Amino acid oxidase from C. rhodostoma snake venom is a potential antineoplastic agent against HEL 92.1.7 and SET-2 JAK2V617F-positive cells as it activates the extrinsic apoptosis pathway.
Subject(s)
Humans , Apoptosis , Betaine , L-Amino Acid Oxidase , Mutation , Myelodysplastic-Myeloproliferative Diseases , Snake Venoms/toxicityABSTRACT
BACKGROUND: Myeloproliferative neoplasms are Philadelphia chromosome-negative diseases characterized by hyperproliferation of mature myeloid cells, associated or not with the Janus kinase 2 tyrosine kinase mutation, JAK2V617F. As there is no curative therapy, researchers have been investigating new drugs to treat myeloproliferative neoplasms, including l-amino acid oxidase from Calloselasma rhodostoma snake venom (CR-LAAO), which is a toxin capable of eliciting apoptosis in several tumor cell lines. OBJECTIVE: To evaluate the effects of l-amino acid oxidase from C. rhodostoma snake venom in the apoptotic machinery of JAK2-mutated cell lines. METHODS: The HEL 92.1.7 and SET-2 cell lines were cultured with l-amino acid oxidase and catalase for 12h at 37°C in 5% carbon dioxide. The cell viability was assessed by the multi-table tournament method, the level of apoptosis was measured by ï¬ow cytometry, and the expression of cysteine-dependent aspartate-specific proteases and cleaved Poly(ADP-ribose) polymerase were analyzed by Western blotting. RESULTS: l-Amino acid oxidase from C. rhodostoma snake venom was cytotoxic to HEL 92.1.7 and SET-2 cells (50% inhibitory concentration=0.15µg/mL and 1.5µg/mL, respectively) and induced apoptosis in a concentration-dependent manner. Cell treatment with catalase mitigated the l-amino acid oxidase toxicity, indicating that hydrogen peroxide is a key component of its cytotoxic effect.The activated caspases 3 and 8 expression and cleaved PARP in HEL 92.1.7 and SET-2 cells confirmed the apoptosis activation by CR-LAAO. CONCLUSIONS: l-Amino acid oxidase from C. rhodostoma snake venom is a potential antineoplastic agent against HEL 92.1.7 and SET-2 JAK2V617F-positive cells as it activates the extrinsic apoptosis pathway.
ABSTRACT
The classical chromosome Philadelphia-negative myeloproliferative neoplasms (MPNs) are a group of disorders that share clinical, hematological, and histological features. Proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) are elevated in patients with MPN. The aim of this study was to verify the association between the polymorphisms of TNF gene (-308G/A and -238 G/A) in BCR-ABL-negative MPN in our population. Blood samples obtained from MPN patients were genotyped for the JAK2V617F mutation and both TNF polymorphisms using PCR-RFLP. Thirty three (26.8%) patients with polycythemia vera (PV), 35 (28.7%) essential thrombocythemia (ET), 22 (17.7%) primary myelofibrosis (PMF), and 33 (26.8%) with unclassifiable MPN (MPNu) were included in the study. The JAK2 V617F mutation was detected in 94 (76.42%) patients. Were observed a significant increase on the frequency of the TNF-238 GA genotype in MPN patients compared to controls (OR=2.21, 95% CI=1.02-4.80, P<0.04). The distribution of the genotypes and allelic frequencies of TNF-308 was significantly different among the MPNs, JAK2V617F positive, PV and PMF, and controls. Our data has demonstrated that the polymorphisms on TNF-238 GA, TNF-308 GA were associated to MPN development in this population, triggered by JAK2 V617F mutation.
Subject(s)
Janus Kinase 2/genetics , Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/genetics , Polycythemia Vera/genetics , Polymorphism, Genetic , Primary Myelofibrosis/genetics , Thrombocythemia, Essential/genetics , Tumor Necrosis Factor-alpha/genetics , Adult , Aged , Alleles , Brazil , Case-Control Studies , DNA Mutational Analysis , Female , Gene Expression , Genetic Predisposition to Disease , Humans , Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/diagnosis , Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/pathology , Male , Middle Aged , Polycythemia Vera/diagnosis , Polycythemia Vera/pathology , Primary Myelofibrosis/diagnosis , Primary Myelofibrosis/pathology , Promoter Regions, Genetic , Thrombocythemia, Essential/diagnosis , Thrombocythemia, Essential/pathologyABSTRACT
BACKGROUND: Anagrelide represents a treatment option for essential thrombocythemia, although its place in therapy remains controversial. AIM: To assess the impact of mutational status in response rates and development of adverse events during long-term use of anagrelide. METHODS: We retrospectively evaluated 67 patients with essential thrombocythemia treated with anagrelide during 68 (4-176) months. RESULTS: Mutational frequencies were 46.3%, 28.3%, and 1.5% for JAK2V617F, CALR and MPL mutations. Anagrelide yielded a high rate of hematologic responses, which were complete in 49.25% and partial in 46.25%, without differences among molecular subsets. The rate of thrombosis during treatment was one per 100 patient-years, without excess bleeding. Anemia was the major adverse event, 30.3% at 5-yr follow-up, being more frequent in CALR(+) (P < 0.05). Myelofibrotic transformation developed in 14.9% (12.9%, 21%, and 12.5% in JAK2V617F(+), CALR(+), and triple-negative patients, respectively, P = NS) and those treated >60 months were at higher risk, OR (95% CI) 9.32 (1.1-78.5), P < 0.01, indicating the need for bone marrow monitoring during prolonged treatment. CONCLUSION: Although CALR(+) patients were at higher risk of developing anemia, anagrelide proved effective among all molecular subsets, indicating that mutational status does not seem to represent a major determinant of choice of cytoreductive treatment among essential thrombocythemia therapies.
Subject(s)
Calreticulin/genetics , Janus Kinase 2/genetics , Platelet Aggregation Inhibitors/administration & dosage , Quinazolines/administration & dosage , Receptors, Thrombopoietin/genetics , Thrombocythemia, Essential/drug therapy , Adolescent , Adult , Aged , Aged, 80 and over , Anemia/etiology , Anemia/pathology , Calreticulin/immunology , Child , Female , Follow-Up Studies , Gene Expression , Humans , Janus Kinase 2/immunology , Male , Middle Aged , Mutation , Platelet Aggregation Inhibitors/adverse effects , Primary Myelofibrosis/etiology , Primary Myelofibrosis/pathology , Quinazolines/adverse effects , Receptors, Thrombopoietin/immunology , Retrospective Studies , Thrombocythemia, Essential/genetics , Thrombocythemia, Essential/immunology , Thrombocythemia, Essential/pathologyABSTRACT
Primary myelofibrosis is a Philadelphia-negative myeloproliferative neoplasm characterized by clonal myeloid expansion, followed by progressive fibrous connective tissue deposition in the bone marrow, resulting in bone marrow failure. Clonal evolution can also occur, with an increased risk of transformation to acute myeloid leukemia. In addition, disabling constitutional symptoms secondary to the high circulating levels of proinflammatory cytokines and hepatosplenomegaly frequently impair quality of life. Herein the main current treatment options for primary myelofibrosis patients are discussed, contemplating disease-modifying therapeutics in addition to palliative measures, in an individualized patient-based approach
Subject(s)
Humans , Janus Kinase 2 , Primary Myelofibrosis , Myeloproliferative DisordersABSTRACT
ABSTRACTMyeloproliferative neoplasms are caused by a clonal proliferation of a hematopoietic progenitor. First described in 1951 as 'Myeloproliferative Diseases' and reevaluated by the World Health Organization classification system in 2011, myeloproliferative neoplasms include polycythemia vera, essential thrombocythemia and primary myelofibrosis in a subgroup called breakpoint cluster region-Abelson fusion oncogene-negative neoplasms. According to World Health Organization regarding diagnosis criteria for myeloproliferative neoplasms, the presence of the JAK2 V617F mutation is considered the most important criterion in the diagnosis of breakpoint cluster region-Abelson fusion oncogene-negative neoplasms and is thus used as a clonal marker. The V617F mutation in the Janus kinase 2(JAK2) gene produces an altered protein that constitutively activates the Janus kinase/signal transducers and activators of transcription pathway and other pathways downstream as a result of signal transducers and activators of transcription which are subsequently phosphorylated. This affects the expression of genes involved in the regulation of apoptosis and regulatory proteins and modifies the proliferation rate of hematopoietic stem cells.
Subject(s)
Humans , Male , Female , Hematologic Neoplasms , STAT Transcription Factors , Janus Kinase 2 , Hematopoietic Stem Cells , Myelodysplastic-Myeloproliferative DiseasesABSTRACT
Myeloproliferative neoplasms are caused by a clonal proliferation of a hematopoietic progenitor. First described in 1951 as 'Myeloproliferative Diseases' and reevaluated by the World Health Organization classification system in 2011, myeloproliferative neoplasms include polycythemia vera, essential thrombocythemia and primary myelofibrosis in a subgroup called breakpoint cluster region-Abelson fusion oncogene-negative neoplasms. According to World Health Organization regarding diagnosis criteria for myeloproliferative neoplasms, the presence of the JAK2 V617F mutation is considered the most important criterion in the diagnosis of breakpoint cluster region-Abelson fusion oncogene-negative neoplasms and is thus used as a clonal marker. The V617F mutation in the Janus kinase 2 (JAK2) gene produces an altered protein that constitutively activates the Janus kinase/signal transducers and activators of transcription pathway and other pathways downstream as a result of signal transducers and activators of transcription which are subsequently phosphorylated. This affects the expression of genes involved in the regulation of apoptosis and regulatory proteins and modifies the proliferation rate of hematopoietic stem cells.
ABSTRACT
Obesity is a public health problem that contributes to the development of insulin resistance, which is associated with an excessive accumulation of lipids in skeletal muscle tissue. There is evidence that soy protein can decrease the ectopic accumulation of lipids and improves insulin sensitivity; however, it is unknown whether soy isoflavones, particularly genistein, can stimulate fatty acid oxidation in the skeletal muscle. Thus, we studied the mechanism by which genistein stimulates fatty acid oxidation in the skeletal muscle. We showed that genistein induced the expression of genes of fatty acid oxidation in the skeletal muscle of Zucker fa/fa rats and in leptin receptor (ObR)-silenced C2C12 myotubes through AMPK phosphorylation. Furthermore, the genistein-mediated AMPK phosphorylation occurred via JAK2, which was possibly activated through a mechanism that involved cAMP. Additionally, the genistein-mediated induction of fatty acid oxidation genes involved PGC1α and PPARδ. As a result, we observed that genistein increased fatty acid oxidation in both the control and silenced C2C12 myotubes, as well as a decrease in the RER in mice, suggesting that genistein can be used in strategies to decrease lipid accumulation in the skeletal muscle.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Anticarcinogenic Agents/pharmacology , Fatty Acids/metabolism , Genistein/pharmacology , Janus Kinase 2/metabolism , Muscle Fibers, Skeletal/metabolism , Myoblasts, Skeletal/metabolism , Receptors, Leptin/metabolism , AMP-Activated Protein Kinases/genetics , Animals , Cell Line , Enzyme Activation/drug effects , Enzyme Activation/genetics , Fatty Acids/genetics , Janus Kinase 2/genetics , Male , Mice , Oxidation-Reduction/drug effects , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha , Phosphorylation/drug effects , Rats , Rats, Zucker , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, Leptin/genetics , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Myeloproliferative neoplasms are clonal diseases of hematopoietic stem cells characterized by myeloid hyperplasia and increased risk of developing acute myeloid leukemia. Myeloproliferative neoplasms are caused, as any other malignancy, by genetic defects that culminate in the neoplastic phenotype. In the past six years, since the identification of JAK2V617F, we have experienced a substantial increase in our knowledge about the genetic mechanisms involved in the genesis of myeloproliferative neoplasms. Mutations described in several genes have revealed a considerable degree of molecular homogeneity between different subtypes of myeloproliferative neoplasms. At the same time, the molecular differences between each subtype have become clearer. While mutations in several genes, such as JAK2, myeloproliferative leukemia (MPL) and LNK have been validated in functional assays or animal models as causative mutations, the roles of other recurring mutations in the development of disease, such as TET2 and ASXL1 remain to be elucidated. In this review we will examine the most prevalent recurring gene mutations found in myeloproliferative neoplasms and their molecular consequences.
ABSTRACT
Myeloproliferative neoplasms are clonal diseases of hematopoietic stem cells characterized by myeloid hyperplasia and increased risk of developing acute myeloid leukemia. Myeloproliferative neoplasms are caused, as any other malignancy, by genetic defects that culminate in the neoplastic phenotype. In the past six years, since the identification of JAK2V617F, we have experienced a substantial increase in our knowledge about the genetic mechanisms involved in the genesis of myeloproliferative neoplasms. Mutations described in several genes have revealed a considerable degree of molecular homogeneity between different subtypes of myeloproliferative neoplasms. At the same time, the molecular differences between each subtype have become clearer. While mutations in several genes, such as JAK2, myeloproliferative leukemia (MPL) and LNK have been validated in functional assays or animal models as causative mutations, the roles of other recurring mutations in the development of disease, such as TET2 and ASXL1 remain to be elucidated. In this review we will examine the most prevalent recurring gene mutations found in myeloproliferative neoplasms and their molecular consequences.