• BMB Reports
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• 제54권12호
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• pp.626-631
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• 2021

Janus kinase 2 (JAK2), a non-receptor tyrosine kinase, is a critical component of cytokine and growth factor signaling pathways regulating hematopoietic cell proliferation. JAK2 mutations are associated with multiple myeloproliferative neoplasms. Although physiological and pathological functions of JAK2 in hematopoietic tissues are well-known, such functions of JAK2 in the nervous system are not well studied yet. The present study demonstrated that JAK2 could negatively regulate neuronal differentiation of mouse embryonic stem cells (ESCs). Depletion of JAK2 stimulated neuronal differentiation of mouse ESCs and activated glycogen synthase kinase 3β, Fyn, and cyclin-dependent kinase 5. Knockdown of JAK2 resulted in accumulation of GTP-bound Rac1, a Rho GTPase implicated in the regulation of cytoskeletal dynamics. These findings suggest that JAK2 might negatively regulate neuronal differentiation by suppressing the GSK-3β/Fyn/CDK5 signaling pathway responsible for morphological maturation.

• 생명과학회지
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• 제30권10호
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• pp.867-876
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• 2020

본 연구는 magnolol에 의한 UVB 유도 세포 손상의 복구를 조사하였다. 우리는 약물재배치를 위해 STAT3 기작을 분석하였고, magnolol HDF 세포에서 세포 생존력을 향상시키며, STAT3의 억제제인 것을 확인하였다. IL-6, UVB 및 IFNγ로 처리 된 HDF 세포는 Jak2 및 인산화 된 STAT3 (p-STAT3)의 높은 발현을 나타냈다. Magnolol 의 처리는 UVB 유도 세포에서 Jak2 및 p-STAT3의 발현을 감소시킬 수 있었다. 또한, UVB- 손상된 세포 성장은 용량 의존적 방식으로 재 활성화 및 magnolol 과의 상관 관계가 상당히 증가되었다. UVB 처리 된 HDF 세포에 대한 AG490 (Jak2 억제제) 처리와 비교하여, 세포 증식이 유의하게 증가 하였다. 우리는 AG490 및 magnolol 이 TNF-α 농도를 감소시키는 것을 확인했다. Western blot (단백질 수준)은 오직 magnolol 처리 된 세포에서만 Jak2 및 p-STAT3 발현의 감소를 나타냈고, Jak2, p-STAT3 및 SOCS3의 발현은 또한 magnolol 처리한 세포에서만 증가하였다. 세포를 magnolol 및 ML385 (NRF2 억제제)로 동시 처리시 세포 증식 및 NRF2 발현을 감소시켰다. MMP9의 양은 magnolol 및 ML385 로의 처리에 의해 증가되었다. 종합적으로, 이들 결과는 NRF2, SOCS3, Jak2 및 STAT3의 발현을 조절함으로써 UVB 손상 후 세포를 회복시키는데 있어 magnolol의 가능성을 입증한다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.923-926
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• 2016

The classic BCR-ABL1-negative myeloproliferative neoplasm is an operational sub-category of MPNs that includes polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The JAK2V617F mutation is found in ~ 95% of PV and 50-60% of ET or PMF. In most of the remaining JAK2V617F-negative PV cases, JAK2 exon 12 mutations are present. Amongst the JAK2V617F-negative ET or PMF 5-10% of patients carry mutations in the MPL gene. Prior to 2013, there was no specific molecular marker described in the remaining 30-40% ET and PMF. In December 2013, two research groups independently reported mutations in the gene CALR found specifically in ET (67-71%) and PMF (56-88%) but not in PV. Initially CALR mutations were reported mutually exclusive with JAK2 or MPL. However, co-occurrence of CALR mutations with JAK2V617F has been reported recently in a few MPN cases. Many studies have reported important diagnostic and prognostic significance of CALR mutations in ET and PMF patients and CALR mutation screening has been proposed to be incorporated into WHO diagnostic criteria for MPN. It is suggestive in diagnostic workup of MPN that CALR mutations should not be studied in MPN patients who carry JAK2 or MPL mutations. However JAK2V617F and CALR positive patients might have a different phenotype and clinical course, distinct from the JAK2-positive or CALR-positive subgroups and identification of the true frequency of these patients may be an important factor for defining the prognosis, risk factors and outcomes for MPN patients.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7889-7892
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• 2015

Background: Primary idiopathic myelofibrosis (PMF) is a clonal Ph-chromosome negative myeloproliferative neoplasm characterized by dysregulated kinase signaling and release of abnormal cytokines. In the recent past, following JAK2 V617F mutation invention, important revolution has been made in the molecular diagnostic biology of this disease. The rational of this study was to determine the mutational status of JAK2 V617F in Pakistan patients with PMF. Materials and Methods: In this cross sectional study, 20 patients with PMF were enrolled from January 2011 to December 2014. Diagnosis was based on WHO criteria for PMF. All patients were screened for G-T point mutation (V617F) in the JAK2 gene on chromosome 9 by allele specific PCR. Results: The mean age was $57.9{\pm}16.5years$. The male to female ratio was 3:1. The frequency of JAK2 V617F positivity in our PMF patients was found to be 55%. Positive correlations of JAK2 V617F mutation were established with high TLC count, raised LDH and marked splenomegaly (P<0.05). No correlation of JAK2 V617F could be established with age and gender (P>0.05). Conclusions: The JAK2 V617F mutation frequency in our PMF patients was similar to those reported previously. In our hands JAK2 V617F mutated patients expressed an aggressive disease phenotype. Screening for the mutation in all suspected PMF cases could be beneficial in differentiating patients with reactive and clonal marrow fibrosis.

• Asian Pacific Journal of Cancer Prevention
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• 제17권10호
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• pp.4647-4653
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• 2016

Background: The discovery of somatic acquired mutations of JAK2 (V617F) in Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPNs) including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) has not only improved rational disease classification and prognostication but also brings new understanding insight into the pathogenesis of diseases. Dosage effects of the JAK2 (V617F) allelic burden in Ph-negative MPNs may partially influence clinical presentation, disease progression, and treatment outcome. Material and Methods: Pyrosequencing was performed to detect JAK2 (V617F) and MPL (W515K/L) and capillary electrophoresis to identify CALR exon 9 mutations in 100 samples of Ph-negative MPNs (38.0 PV, 55 ET, 4 PMF, and 3 MPN-U). Results: The results showed somatic mutations of JAK2 (V617F) in 94.7% of PV, 74.5% of ET, 25.0% of PMF, and all MPN-U. A high proportion of JAK2 (V617F) mutant allele burden (mutational load > 50.0%) was predominantly observed in PV when compared with ET. Although a high level of JAK2 (V617F) allele burden was strongly associated with high WBC counts in both PV and ET, several hematological parameters (hemoglobin, hematocrit, and platelet count) were independent of JAK2 (V617F) mutational load. MPL (W515K/L) mutations could not be detected whereas CALR exon 9 mutations were identified in 35.7% of patients with JAK2 negative ET and 33.3% with JAK2 negative PMF. Conclusions: The JAK2 (V617F) allele burden may be involved in progression of MPNs. Furthermore, a high level of JAK2 (V617F) mutant allele appears strongly associated with leukocytosis in both PV and ET.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7327-7330
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• 2015

Background: Essential thrombocythemia (ET) is a clonal hemopoietic stem cell myeloproliferative neoplasm characterized by persistent thrombocytosis along with megakaryocytic hyperplasia. In the last decade following the identification of an acquired JAK2 V617F mutation, there has been acceleration in our understanding of this disease. The rational of this study was to determine the mutational profile of JAK2 V617F in Pakistan patients with ET. Materials and Methods: In this retrospective cross sectional study, 21 patients with ET were enrolled from January 2011 to December 2014. Patients were diagnosed based on WHO criteria for essential thrombocythemia. Complete blood count was done on an automated hematology analyzer, while JAK2 V617F expression was evaluated by polymerase chain reaction. Results: The mean age was $56.7{\pm}19.0$ years (range 18-87) and the male to female ratio was 1:1.1. The frequency of JAK2 V617F positivity in our ET patients was found to be 61.9%. The mean hemoglobin was $11.7{\pm}2.4$ g/dl with a total leukocyte count of $13.3{\pm}8.1{\times}109/l$ and a platelet count of $1188{\pm}522{\times}109/l$. Positive correlations for JAK2 V617F mutation were established with high TLC count and raised LDH (P<0.05). No correlation of JAK2 V617F could be established with age and gender (P>0.05). Conclusions: JAK2 V617F mutation frequency in our ET patients was similar to those reported previously. Screening for the mutation in all suspected essential thrombocythemia cases could be beneficial in differentiating patients with reactive and clonal thrombocytosis.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1053-1055
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• 2016

Background: Polycythemia rubra vera (PV), being a primary polycythemia, is caused by neoplastic proliferation of erythroid, megakaryocytic and granulocytic lineages which result in panmyelosis. PV patients have a somatic acquired mutation in the Janus kinase (JAK2) pathway, rendering cell proliferation independent of the normal regulatory mechanisms that regulate erythropoiesis. The rational of this study was to determine the prevalence of the JAK-2 V617F mutation in Pakistani patients with PV. Materials and Methods: In this cross sectional study, 26 patients with PV were enrolled from January 2010 to December 2014. Patients were diagnosed based on WHO criteria for PV. All were screened for G-T point mutation (V617F) in the JAK2 gene on chromosome 9 by an allele specific PCR. Results: The mean age was $53.4{\pm}9.31years$ (range 36-72) and the male to female ratio was 2:1. The frequency of JAK2 V617F positivity in our PV patients was found to be 92.3%. Overall 30.7% of patients were asymptomatic and remaining 69.3% presented with symptomatic disease. The mean hemoglobin was $18.1{\pm}1.9g/dl$ with the mean hematocrit of $55.6{\pm}8.3%$. The mean total leukocyte count was $12.8{\pm}7.1{\times}10^9/l$ and the platelet count was $511{\pm}341.9{\times}10^9/l$. A positive correlation of JAK2 V617F mutation was established with high TLC count (P=0.01). No correlation of JAK2 V617F could be established with age or gender (P>0.05). Conclusions: The JAK2 V617F mutation frequency in our PV patients was similar to those reported internationally. Screening for the mutation in all suspected PV cases could be beneficial in differentiating patients with reactive and clonal erythrocytosis.

• Biomolecules & Therapeutics
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• 제21권2호
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• pp.97-106
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• 2013

Chronic hepatitis C virus (HCV) infection is responsible for the development of liver cirrhosis and hepatocellular carcinoma. HCV core protein plays not only a structural role in the virion morphogenesis by encapsidating a virus RNA genome but also a non-structural role in HCV-induced pathogenesis by blocking innate immunity. Especially, it has been shown to regulate JAK-STAT signaling pathway through its direct interaction with Janus kinase (JAK) via its proline-rich JAK-binding motif ($^{79}{\underline{P}}GY{\underline{P}}WP^{84}$). However, little is known about the physiological significance of this HCV core-JAK association in the context of the virus life cycle. In order to gain an insight, a mutant HCV genome (J6/JFH1-79A82A) was constructed to express the mutant core with a defective JAK-binding motif ($^{79}{\underline{A}}GY{\underline{A}}WP^{84}$) using an HCV genotype 2a infectious clone (J6/JFH1). When this mutant HCV genome was introduced into hepatocarcinoma cells, it was found to be severely impaired in its ability to produce infectious viruses in spite of its robust RNA genome replication. Taken together, all these results suggest an essential requirement of HCV core-JAK protein interaction for efficient production of infectious viruses and the potential of using core-JAK blockers as a new anti-HCV therapy.

• Asian Pacific Journal of Cancer Prevention
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• 제15권4호
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• pp.1681-1684
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• 2014

Objective: To investigate interferon (IFN) alpha 2 b for treating patients with JAK2V617F positive polycythemia vera (PV) and essential thrombocytosis (ET). Methods: Interferon alpha 2 b was used to treat patients with JAK2V617F positive PV and ET. In control group, hydroxyurea was used. Endpoint of study was to compare rates of hematological and molecular remission. Results: Patients in the interferon alpha 2 b group achieved higher rates of hematologic and molecular remission than patients in the hydroxyurea group, with a lower incidence of thrombosis. Conclusion: Compared with hydroxyurea, interferon alpha 2 b could reduce JAK2V617F load for patients with PV and ET, and achieve higher molecular remission, improve treatment efficacy and reduce complications.

• 치위생과학회지
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• 제17권1호
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• pp.81-86
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• 2017

Bacterial infection and smoking are an important risk factors involved in the development and progression of periodontitis. However, the signaling mechanism underlying the host immune response is not fully understood in periodontal lesions. In this study, we determined the expression of janus kinase (JAK)/signal transducer and activator of transcription (STAT) on Porphyromonas gingivalis lipopolysaccharide (LPS)- and nicotine-induced cytotoxicity and the production of inflammatory mediators, using osteoblasts. The cells were cultured with 5 mM nicotine in the presence of $1{\mu}g/ml$ LPS. Cell viability was determined using MTT assay. The role of JAK on inflammatory mediator expression and production, and the regulatory mechanisms involved were assessed via enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, and Western blot analysis. LPS- and nicotine synergistically induced the production of cyclooxgenase-2 (COX-2) and prostaglandin $E_2$ ($PGE_2$) and increased the protein expression of JAK/STAT. Treatment with an JAK inhibitor blocked the production of COX-2 and $PGE_2$ as well as the expression of pro-inflammatory cytokines, such as tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$ ($IL-1{\beta}$), and IL-6 in LPS- and nicotine-stimulated osteoblasts. These results suggest that JAK/STAT is closely related to the LPS- and nicotine-induced inflammatory effects and is likely to regulate the immune response in periodontal disease associated with dental plaque and smoking.