Chronic myeloproliferative diseases (MPDs) are heterogenous group of haematological malignant disorders. It is now a well recognized fact that the JAK2 (V617F) mutation occurs in majority of the patients with polycythaemia vera (PV) and half of those with myelofibrosis and essential thrombocythaemia. The presence of JAK2 (V617F) mutation is considered an important criterion for the exclusion of secondary-reactive from clonal disorders. In the present uni-institutional study, we analyzed the JAK2 (V617F) mutation status in the ethnic Malay and Chinese patients who were diagnosed as MPDs.
Mutations of JAK2V617F, CALR, and MPL genes confirm the diagnosis of myeloproliferative neoplasm (MPN). This study aims to determine the genetic profile of JAK2V617F, CALR exon 9 Type 1 (52 bp deletion) and Type 2 (5 bp insertion), and MPL W515 L/K genes among Malaysian patients and correlate these mutations with clinical and hematologic parameters in MPN. Mutations of JAK2V617F, CALR, and MPL were analyzed in 159 Malaysian patients using allele-specific polymerase chain reaction, including 76 polycythemia vera (PV), 41 essential thrombocythemia (ET), and 42 primary myelofibrosis (PMF) mutations, and the demographics of the patients were retrieved. The result showed that 73.6% JAK2V617F, 5.66% CALR, and 27.7% were triple-negative mutations. No MPL W515L/K mutation was detected. In ET and PMF, the predominance type was the CALR Type 1 mutation. In JAK2V617F mutant patients, serum LDH was significantly higher in PMF compared to PV and ET. PV has a higher risk of evolving to post PV myelofibrosis compared to ET. A thrombotic event at initial diagnosis of 40.9% was high compared to global incidence. Only one PMF patient had a CALR mutation that transformed to acute myeloid leukemia. JAK2V617F and CALR mutations play an important role in diagnostics. Hence, every patient suspected of having a myeloproliferative neoplasm should be screened for these mutations.
Background: In recent years, a somatic point mutation in the Janus Kinase 2 (JAK2) gene (1849 G→T, V617F) has been reported to occur in over 90% of patients with polycythemia vera (PV). Another JAK2 mutation in exon 12 had been described and shown capable of activating erythropoietin signaling pathways. Objective: In this study, we aimed to determine the frequency of Jak2 mutations (JAK2V617F and JAK2 exon 12) as well as their relationships with hematological parameters in Sudanese patients with myeloproliferative disorders (MPD). A comparison with findings of published studies from other geographic regions was included. Materials and Methods: From each of a total of 83 polycythaemia patients, six milliliters (ml) of venous blood were collected and processed for molecular analysis and measurement of serum erythropoietin level by enzyme-linked immunoassay (ELISA). The JAK2 V617F mutation was determined using an allele-specific competitive blocker (ACB) -PCR assay and High Resolution Melting (HRM) analysis was applied for the JAK2 exon 12 mutation. Results: According to patients’ history and the results for EPO levels, nine (10.7 %) out of 83 patients were found to have secondary polycythaemia and 74 (89.3%) PV. The overall frequency of the 2 JAK2 mutations was 94.6% in our Sudanese PV patients, JAK2V617F being found in 91% and JAK2 exon 12 mutations in 8.1%.Conclusion: In summary JAK2 V617F and JAK2 exon 12 mutations are very common in Sudanese PC cases.
Cytokine-inducible SH2 domain-containing protein (CISH), a member of the suppressor of cytokine signaling family of negative feedback regulators, is induced by cytokines that activate STAT5 and can inhibit STAT5 signaling in vitro. However, demonstration of a definitive in vivo role for CISH during development has remained elusive. This study employed expression analysis and morpholino-mediated knockdown in zebrafish in concert with bioinformatics and biochemical approaches to investigate CISH function. Two zebrafish CISH paralogs were identified, cish.a and cish.b, with high overall conservation (43-46% identity) with their mammalian counterparts. The cish.a gene was maternally derived, with transcripts present throughout embryogenesis, and increasing at 4-5 d after fertilization, whereas cish.b expression commenced at 8 h after fertilization. Expression of cish.a was regulated by the JAK2/STAT5 pathway via conserved tetrameric STAT5 binding sites (TTCN3GAA) in its promoter. Injection of morpholinos targeting cish.a, but not cish.b or control morpholinos, resulted in enhanced embryonic erythropoiesis, myelopoiesis, and lymphopoiesis, including a 2- 3-fold increase in erythrocytic markers. This occurred concomitantly with increased activation of STAT5. This study indicates that CISH functions as a conserved in vivo target and regulator of STAT5 in the control of embryonic hematopoiesis.
We investigated the role of lipocalin-2 (LCN-2) and its receptor (SLC22A17) in mediating clonal dominance in a patient with both BCR-ABL and JAK2-V617F mutations. LCN-2 mRNA showed a near 50-fold increase in expression, accompanied by down-regulation of SLC22A17, coinciding with increase in BCR-ABL transcripts, loss of JAK2-V617F and change of clinical phenotype from polycythaemia vera to chronic myeloid leukaemia. These changes were reversed after commencing imatinib mesylate. Consistent with experimental studies, BCR-ABL+ cells express LCN-2 leading to suppression of BCR-ABL- cells and explain their eventual dominance when occurring together with JAK2-V617F.
The co-occurrence of JAK2 V617F mutation with BCR-ABL reciprocal translocation is uncommon. We report a 60-year-old man who initially presented with phenotype of polycythemia vera (PV), which evolved into chronic myeloid leukemia and back to PV once treatment with imatinib was commenced. JAK2 V617F mutation and BCR-ABL fusion transcripts were detected in the initial sample. However, JAK2 V617F alleles diminished when BCR-ABL mRNA burden increased and reappeared once the patient was commenced on imatinib. The dynamic interaction between JAK2 V617F and BCR-ABL implies that two independent clones exist with the JAK2 V617F clone only achieving clonal dominance when BCR-ABL positive clones are suppressed by imatinib.
Increased airway smooth muscle (ASM) mass is a prominent hallmark of airway remodeling in asthma. Inhaled corticosteroids and long-acting beta2-agonists remain the mainstay of asthma therapy, however are not curative and ineffective in attenuating airway remodeling. The geranyl acetophenone 2,4,6-trihydroxy-3-geranyl acetophenone (tHGA), an in-house synthetic non-steroidal compound, attenuates airway hyperresponsiveness and remodeling in murine models of asthma. The effect of tHGA upon human ASM proliferation, migration and survival in response to growth factors was assessed and its molecular target was determined. Following serum starvation and induction with growth factors, proliferation and migration of human bronchial smooth muscle cells (hBSMCs) treated with tHGA were significantly inhibited without any significant effects upon cell survival. tHGA caused arrest of hBSMC proliferation at the G1 phase of the cell cycle with downregulation of cell cycle proteins, cyclin D1 and diminished degradation of cyclin-dependent kinase inhibitor (CKI), p27Kip1. The inhibitory effect of tHGA was demonstrated to be related to its direct inhibition of AKT phosphorylation, as well as inhibition of JNK and STAT3 signal transduction. Our findings highlight the anti-remodeling potential of this drug lead in chronic airway disease.