• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2453-2459
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• 2014

Ginsenoside Rg1 is one effective anticancer and antioxidant constituent of total saponins of Panax ginseng (TSPG), which has been shown to have various pharmacological effects. Our previous study demonstrated that Rg1 had anti-tumor activity in K562 leukemia cells. The aim of this study was designed to investigate whether Rg1 could induce apoptosis in TF-1/Epo cells and further to explore the underlying molecular mechanisms. Here we found that Rg1 could inhibit TF-1/Epo cell proliferation and induce cell apoptosis in vitro in a concentration and time dependent manner. It also suppressed the expression of EpoR on the surface membrane and inhibited JAK2/STAT5 pathway activity. Rg1 induced up-regulation of Bax, cleaved caspase-3 and C-PAPR protein and down-regulation of Bcl-2 and AG490, a JAK2 specific inhibitor, could enhance the effects of Rg1. Our studies showed that EpoR-mediated JAK2/STAT5 signaling played a key role in Rg1-induced apoptosis in TF-1/Epo cells. These results may provide new insights of Rg1 protective roles in the prevention a nd treatment of leukemia.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5071-5076
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• 2014

Cholangiocarcinoma (CCA) is one of the aggressive cancers with a very poor prognosis. Several efforts have been made to identify and develop new agents for prevention and treatment of this deadly disease. In the present study, we examined the anticancer effect of luteolin on human CCA, KKU-M156 cells. Sulforhodamine B assays showed that luteolin had potent cytotoxicity on CCA cells with IC50 values of $10.5{\pm}5.0$ and $8.7{\pm}3.5{\mu}M$ at 24 and 48 h, respectively. Treatment with luteolin also caused a concentration-dependent decline in colony forming ability. Consistent with growth inhibitory effects, luteolin arrested cell cycle progression at the G2/M phase in a dose-dependent manner as assessed by flow cytometry analysis. Protein expression of cyclin A and Cdc25A was down-regulated after luteolin treatment, supporting the arrest of cells at the G2/M boundary. Besides evident G2/M arrest, luteolin induced apoptosis of KKU-M156 cells, demonstrated by a distinct sub-G1 apoptotic peak and fluorescent dye staining. A decrease in the level of anti-apoptotic Bcl-2 protein was implicated in luteolin-induced apoptosis. We further investigated the effect of luteolin on JAK/STAT3, which is an important pathway involved in the development of CCA. The results showed that interleukin-6 (IL-6)-induced JAK/STAT3 activation in KKU-M156 cells was suppressed by treatment with luteolin. Treatment with a specific JAK inhibitor, AG490, and luteolin diminished IL-6-stimulated CCA cell migration as assessed by wound healing assay. These data revealed anticancer activity of luteolin against CCA so the agent might have potential for CCA prevention and therapy.

• Biomolecules & Therapeutics
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• v.26 no.5
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• pp.464-473
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• 2018

Cripto is a small glycosylphosphatidylinositol-anchored signaling protein that can detach from the anchored membrane and stimulate proliferation, migration, differentiation, vascularization, and angiogenesis. In the present study, we demonstrated that Cripto positively affected proliferation and survival of mesenchymal stem cells (MSCs) without affecting multipotency. Cripto also increased expression of phosphorylated janus kinase 2 (p-JAK2), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), 78 kDa glucose-regulated protein (GRP78), c-Myc, and cyclin D1. Notably, treatment with an anti-GRP78 antibody blocked these effects. In addition, pretreatment with STAT3 short interfering RNA (siRNA) inhibited the increase in p-JAK2, c-Myc, cyclin D1, and BCL3 levels caused by Cripto and attenuated the pro-survival action of Cripto on MSCs. We also found that incubation with Cripto protected MSCs from apoptosis caused by hypoxia or $H_2O_2$ exposure, and the level of caspase-3 decreased by the Cripto-induced expression of B-cell lymphoma 3-encoded protein (BCL3). These effects were sensitive to down-regulation of BCL3 expression by BCL3 siRNA. Finally, we showed that Cripto enhanced expression levels of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and hepatocyte growth factor (HGF). In summary, our results demonstrated that Cripto activated a novel biochemical cascade that potentiated MSC proliferation and survival. This cascade relied on phosphorylation of JAK2 and STAT3 and was regulated by GRP78. Our findings may facilitate clinical applications of MSCs, as these cells may benefit from positive effects of Cripto on their survival and biological properties.

• IMMUNE NETWORK
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• v.11 no.6
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• pp.348-357
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• 2011

Background: N-myc downstream-regulated gene 2 (NDRG2), a member of a newly described family of differentiation-related genes, has been characterized as a regulator of dendritic cells. However, the role of NDRG2 on the expression and activation of transcription factors in blood cells remains poorly understood. In this study, we investigated the effects of NDRG2 overexpression on GATA-1 expression in PMAstimulated U937 cells. Methods: We generated NDRG2-overexpressing U937 cell line (U937-NDRG2) and treated the cells with PMA to investigate the role of NDRG2 on GATA-1 expression. Results: NDRG2 overexpression in U937 cells significantly induced GATA-1 expression in response to PMA stimulation. Interestingly, JAK2/STAT and BMP-4/Smad pathways associated with the induction of GATA-1 were activated in PMA-stimulated U937-NDRG2 cells. We found that the inhibition of JAK2 activation, but not of BMP-4/Smad signaling, can elicit a decrease of PMA-induced GATA-1 expression in U937-NDRG2 cells. Conclusion: The results reveal that NDRG2 promotes the expression of GATA-1 through activation of the JAK2/STAT pathway, but not through the regulation of the BMP-4/Smad pathway in U937 cells. Our findings further suggest that NDRG2 may play a role as a regulator of erythrocyte and megakaryocyte differentiation during hematopoiesis.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.2
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• pp.131-138
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• 2009

The binding of interleukin-6 (IL-6) cytokine family ligands to the gp130 receptor complex activates the Janus kinase (JAK)/ signal transducer and activator of transcription 3 (STAT3) signal transduction pathway, where STA T3 plays an important role in cell survival and tumorigenesis. Constitutive activation of STAT3 has been frequently observed in many cancer tissues, and thus, blocking of the gp130 signaling pathway, at the JAK level, might be a useful therapeutic approach for the suppression of STAT3 activity, as anticancer therapy. AG490 is a tyrphostin tyrosine kinase inhibitor that has been extensively used for inhibiting JAK2 in vitro and in vivo. In this study, we demonstrate a novel mechanism associated with AG490 that inhibits the JAK/STAT3 pathway. AG490 induced downregulation of gp130, a common receptor for the IL-6 cytokine family compounds, but not JAK2 or STAT3, within three hours of exposure. The downregulation of gp130 was not caused by enhanced degradation of gp130 or by inhibition of mRNA transcription. It most likely occurred by translation inhibition of gp130 in association with phosphorylation of the eukaryotic initiation factor-2 a. The inhibition of protein synthesis of gp130 by AG490 led to immediate loss of mature gp130 in cell membranes, due to its short half-life, thereby resulting in reduction in the STAT3 response to IL-6. Taken together, these results suggest that AG490 blocks the STAT3 activation pathway via a novel pathway.

• Journal of Evidence-Based Herbal Medicine
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• v.1 no.1
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• pp.1-5
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• 2008

Objectives : The purpose of this study was to investigate the anti-inflammatory effects of extract from Jak-Yak Tang (JYT) on the THP-1 cell and HMC-1 cell. Method : To evaluate of anti-inflammatory of JYT, we examined cytokines production in lipopolysacchride (LPS)-induced THP-1 cell and A23187, PMA-induced HMC-1 cell. Result : Extract of JYT inhibit LPS-induced interleukin (IL)-8 production in human monocyte THP-1 cells. Extract of JYT inhibit A23187, PMA-induced IL-8, tumor necrosis factor-$\alpha$ (INF-$\alpha$) production in HMC-1 cells. Conclusion : NT down-regulated LPS-induced IL-8 production and A23187, PMA-induced IL-8, TNF-$\alpha$ production, which may be provide a clinical basis for anti-inflammatory properities of JYT.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.12
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• pp.5013-5018
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• 2015

Background: Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders characterized by proliferation of one or more myeloid lineages. Polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) are classical Philadelphia chromosome (Ph)-negative MPN that have a Janus Kinase 2 (JAK2) mutation, especially JAK2V617F in the majority of patients. The major complications of Ph-negative MPNs are thrombosis, hemorrhage, and leukemic transformation. Objective: To study clinical manifestations including symptoms, signs, laboratory findings, and JAK2V617F mutations of Ph-negative MPN (PV, ET and PMF) as well as their complications. Materials and Methods: All Ph-negative MPN (PV, ET and PMF) patients who attended the Hematology Clinic at Maharaj Nakorn Chiang Mai Hospital from January, 1 2003 through December, 31 2013 were retrospectively reviewed for demographic data, clinical characteristics, complete blood count, JAK2V617F mutation analysis, treatment, and complications. Results: One hundred and fifty seven patients were included in the study. They were classified as PV, ET and PMF for 68, 83 and 6 with median ages of 60, 61, and 68 years, respectively. JAK2V617F mutations were detected in 88%, 69%, and 100% of PV, ET and PMF patients. PV had the highest incidence of thrombosis (PV 29%, ET 14%, and PMF 0%) that occurred in both arterial and venous sites whereas PMF had the highest incidence of bleeding (PMF 17%, ET 11%, and PV 7%). During follow up, there was one ET patient that transformed to acute leukemia and five cases that developed thrombosis (three ET and two PV patients). No secondary myelofibrosis and death cases were encountered. Conclusions: Ph-negative MPNs have various clinical manifestations. JAK2V617F mutations are present in the majority of PV, ET, and PMF patients. This study confirmed that thrombosis and bleeding are the most significant complications in patients with Ph-negative MPN.

• The Korea Journal of Herbology
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• v.28 no.4
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• pp.7-16
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• 2013

Objectives : Brassica campestris var narinosa (BCN), Canavalia gladiata DC semen (CGD) and their combinational prescription (BCN+CGD) have been use to demonstrate to regulate hematopoiesis. In the current study, we investigated whether Brassica campestris var narinosa, Canavalia gladiata DC semen and their combinational prescription is related to hemato-potentiating function using Sca-$1^+$ hematopoietic stem cells (Sca-$1^+HSCs$) as a testing system. Methods : Sca-$1^+HSCs$ isolated from femur in C57bl/6 mice with leukopenia and thrombocytopenia induced by cyclophosphamide (CTX). Then, Real-time PCR was performed to measure the mRNA expression, ELISA and haematopoiesis-related gene (EPO, TPO, IL-3, SCF, c-kit, GM-CSF), the phosphorylation of JAK2, GATA-1 and STAT-5a/b were observed by western blot, and the numbers of $CD117^+/Sca-1^+$ cell and the number of granulocyte erythrocyte monocyte macrophage colony-forming units (CFU-GEMM) and erythroid burst forming units (BFU-E), semisolid clonogenic assay was performed. Result : When Sca-$1^+HSCs$ were treated with Brassica campestris var narinosa, Canavalia gladiata DC semen and their combinational prescription with rIL-3/rSCF, the expression of haematopoiesis-related (EPO, TPO, IL-3, SCF, c-kit, and GM-CSF) were significantly increased at the levels of mRNA as well as production in Sca-$1^+HSCs$. Additionally, CGS enhanced phosphorylation of JAK2, GATA-1, and signal transducer and activator of transcription-5a/b (STAT-5a/b) in Sca-$1^+HSCs$. Furthermore, their combinational prescription (BCN+CGD) significantly enhanced the growth rate of granulocyte erythrocyte monocyte macrophage colony-forming units (CFU-GEMM) and erythroid burst forming units (BFU-E) in vitro. Conclusion : These result suggest that Brassica campestris var narinosa (BCN) and Canavalia gladiata DC have hematopoietic enhancement via hematopoietic cytokine-mediated JAK2/GATA-1/STAT-5a/b pathway, and their combinational prescription (BCN+CGD) has superior hematopoietic enhancement to those of individual extracts.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.1077-1079
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• 2011

• 건강소식
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• v.19 no.5 s.198
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• pp.18-23
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• 1995