• The Journal of Internal Korean Medicine
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• v.30 no.4
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• pp.845-857
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• 2009

Background and Objectives : Korean mistletoe lectin (Viscum album coloratum agglutinin, VCA) and bee venom (BV) have been reported to induce apoptosis in various cancer cell lines in vitro and to show antitumor activity against a variety of tumors in animal models. However, the comparative effect of VCA and BV on the anti-cancer effect and mechanisms of action has not been determined. In this study, the effect in a human hepatocellular carcinoma cell line, Hep G2 cells, was examined. Methods : Cytotoxic effects of VCA and BV on Hep G2 cells were determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay in litro. The apoptotic cell death was then confirmed by propidium iodide staining and DNA fragmentation analysis. The mechanisms of action were examined by the expression of anti-apoptotic proteins and activation of mitogen-activated protein kinases. The involvement of kinase was examined in VCA or BV-induced apoptosis by using kinase inhibitors. Results : VCA and BV killed Hep G2 cells in a time and dose-dependent manner. Treatment of Hep G2 cells with VCA activated poly (ADP-ribose) polymerase-1 (PARP-1) known as a marker of apoptosis, and mitogen-activated protein kinases signaling pathways including MAPK/ERK, p38 MAPK and JNK. BV also activated PARP-1, MAPK/ERK. and p38 MAPK but not JNK. The expression level of anti-apoptotic molecule, Bcl-X, was decreased by VCA treatment but not by BV. Finally, the phosphorylation level of ERM proteins involved in the cytoskeleton homeostasis was decreased by both stimuli. VCA-induced apoptosis was partially inhibited by in the presence of JNK and p38 inhibitor, but BV only by p38 inhibitor. Conclusions : VCA-induced apoptosis is dependent on the activation of p38 and JNK. while BV-induced apoptosis is mediated by p38 activation in Hep G2 cells.

• Journal of Life Science
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• v.23 no.11
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• pp.1342-1350
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• 2013

We examined the effect of hydrogen sulfide ($H_2S$) in chemical hypoxia-induced injury in mouse hepatocytes. Cell viability was significantly decreased by cobalt chloride ($CoCl_2$), a well-known hypoxia mimetic agent in a time- and dose- dependent manner. Sodium hydrosulfide (NaHS, a donor of $H_2S$) pretreatment before exposure to $CoCl_2$ significantly attenuated the $CoCl_2$-induced decrease of cell viability. $CoCl_2$ treatment resulted in an increase of intracellular ROS generation, which is inhibited by NaHS or N-acetyl-cysteine (NAC, a ROS scavenger), and p38 MAPK phosphorylation, which is also blocked by NaHS or NAC. The $CoCl_2$-induced increase of the Bax/Bcl-2 ratio was attenuated by NaHS, NAC, and SB 203580 (p38 MAPK inhibitor). The $CoCl_2$-induced decrease of cell viability was also attenuated by NaHS, NAC, and SB 203580 pretreatment. Additionally, NaHS inhibited the $CoCl_2$-induced COX-2. Similar to the effect of NaHS, NAC blocked $CoCl_2$-induced COX-2 expression. Furthermore, NS-398 (a selective COX-2 inhibitor) attenuated not only the $CoCl_2$-induced increase of the Bax/Bcl-2 ratio, it also decreased cell viability. Taken together, $H_2S$ protects primary cultured mouse hepatocytes against $CoCl_2$-induced cell injury through inhibition of the ROS-activated p38 MAPK cascade and the COX-2 pathway.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1615-1623
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• 2021

Picropodophyllotoxin (PPT), an epimer of podophyllotoxin, is derived from the roots of Podophyllum hexandrum and exerts various biological effects, including anti-proliferation activity. However, the effect of PPT on colorectal cancer cells and the associated cellular mechanisms have not been studied. In the present study, we explored the anticancer activity of PPT and its underlying mechanisms in HCT116 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to monitor cell viability. Flow cytometry was used to evaluate cell cycle distribution, the induction of apoptosis, the level of reactive oxygen species (ROS), assess the mitochondrial membrane potential (Δψm), and multi-caspase activity. Western blot assays were performed to detect the expression of cell cycle regulatory proteins, apoptosis-related proteins, and p38 MAPK (mitogen-activated protein kinase). We found that PPT induced apoptosis, cell cycle arrest at the G1 phase, and ROS in the HCT116 cell line. In addition, PPT enhanced the phosphorylation of p38 MAPK, which regulates apoptosis and PPT-induced apoptosis. The phosphorylation of p38 MAPK was inhibited by an antioxidant agent (N-acetyl-L-cysteine, NAC) and a p38 inhibitor (SB203580). PPT induced depolarization of the mitochondrial inner membrane and caspase-dependent apoptosis, which was attenuated by exposure to Z-VAD-FMK. Overall, these data indicate that PPT induced G1 arrest and apoptosis via ROS generation and activation of the p38 MAPK signaling pathway.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.792-799
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• 2022

As a vital problem in reproductive health, recurrent spontaneous abortion (RSA) affects about 1% of women. We performed this study with an aim to explore the molecular mechanism of interleukin-23 (IL-23) and find optimal or effective methods to improve RSA. First, ELISA was applied to evaluate the expressions of IL-23 and its receptor in HTR-8/SVneo cells after IL-23 treatment. CCK-8, TUNEL, wound healing and transwell assays were employed to assess the proliferation, apoptosis, migration and invasion of HTR-8/SVneo cells, respectively. Additionally, the expressions of apoptosis-, migration-, epithelial-mesenchymal transition- (EMT-) and p38 MAPK signaling pathway-related proteins were measured by western blotting. To further investigate the relationship between IL-23 and p38 MAPK signaling pathway, HTR-8/SVneo cells were treated for 1 h with p38 MAPK inhibitor SB239063, followed by a series of cellular experiments on proliferation, apoptosis, migration and invasion, as aforementioned. The results showed that IL-23 and its receptors were greatly elevated in IL-23-treated HTR-8/SVneo cells. Additionally, IL-23 demonstrated suppressive effects on the proliferation, apoptosis, migration, invasion and EMT of IL-23-treated HTR-8/SVneo cells. More importantly, the molecular mechanism of IL-23 was revealed in this study; that is to say, IL-23 inhibited the proliferation, apoptosis, migration, invasion and EMT of IL-23-treated HTR-8/SVneo cells via activating p38 MAPK signaling pathway. In conclusion, IL-23 inhibits trophoblast proliferation, migration, and EMT via activating p38 MAPK signaling pathway, suggesting that IL-23 might be a novel target for the improvement of RSA.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.5
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• pp.339-346
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• 2000

Using murine immortalized microglial cells (BV-2), we examined the regulation of RANTES production stimulated by lipopolysaccharide (LPS), focusing on the role of mitogen-activated protein kinase (MAPK) and nuclear factor $(NF)-{\kappa}B.$ The result showed that RANTES (regulated upon activation of normal T cell expressed and secreted) was induced at the mRNA and protein levels in a dose- and time-dependent manner in response to LPS. From investigations of second messenger pathways involved in regulating the secretion of RANTES, we found that LPS induced phosphorylation of extracellular signal-regulated kinase (Erk), p38 MAPK and c-Jun-N-terminal kinase (JNK), and activated $(NF)-{\kappa}B.$ To determine whether this MAPK phosphorylation is involved in LPS-stimulated RANTES production, we used specific inhibitors for p38 MAPK and Erk, SB 203580 and PD 98059, respectively. LPS-induced RANTES production was reduced approximately 80% at $25\;{\mu}M$ of SB 203580 treatment. But PD 98059 did not affect RANTES production. Pyrrolidine-dithiocarbamate (PDTC), $(NF)-{\kappa}B$ inhibitor, reduced RANTES secretion. These results suggest that LPS-induced RANTES production in microglial cells (BV-2) is mainly mediated by the coordination of p38 MAPK and $(NF)-{\kappa}B$ cascade.

• Biomedical Science Letters
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• v.25 no.1
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• pp.23-31
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• 2019

The protein kinase $CK2{\alpha}$ (formerly Casein Kinase II) is implicated in tumorigenesis and transformation. However, the mechanisms of $CK2{\alpha}$ activation in breast cancer have yet to be elucidated. This study investigated the mechanisms of $CK2{\alpha}$ activation in estrogen signaling. Estrogen increased reactive oxygen species (ROS) production, $CK2{\alpha}$ activity, and protein expression in estrogen receptor positive ($ER^+$) MCF-7 human breast cancer cells, which were inhibited by the antioxidant N-acetyl-L-cysteine. $H_2O_2$ enhanced $CK2{\alpha}$ activity and protein expression. Human epidermal growth factor (EGF) increased ROS production, $CK2{\alpha}$ activity and protein expression in EGF receptor 2 (HER2)-overexpressing MCF-7 (MCF-7 HER2) cells, but not in MCF-7 cells. Estrogen induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK). The p38 inhibitor, SB202190, blocked estrogen-induced increases in ROS production, $CK2{\alpha}$ activity and $CK2{\alpha}$ protein expression. The data suggest that ROS/p38 MAPK is the key inducer of $CK2{\alpha}$ activation in response to estrogen or EGF.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.4
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• pp.229-238
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• 2022

Severe bacterial infections are frequently accompanied by depressed neutrophil functions. Thus, agents that increase the microbicidal activity of neutrophils could add to a direct antimicrobial therapy. Lysophosphatidylcholine augments neutrophil bactericidal activity via the glycine (Gly)/glycine receptor (GlyR) α2/TRPM2/p38 mitogen-activated protein kinase (MAPK) pathway. However, the direct effect of glycine on neutrophil bactericidal activity was not reported. In this study, the effect of glycine on neutrophil bactericidal activity was examined. Glycine augmented bactericidal activity of human neutrophils (EC₅₀ = 238 μM) in a strychnine (a GlyR antagonist)-sensitive manner. Glycine augmented bacterial clearance in mice, which was also blocked by strychnine (0.4 mg/kg, s.c.). Glycine enhanced NADPH oxidase-mediated reactive oxygen species (ROS) production and TRPM2-mediated [Ca²⁺]_i increase in neutrophils that had taken up E. coli. Glycine augmented Lucifer yellow uptake (fluid-phase pinocytosis) and azurophil granule-phagosome fusion in neutrophils that had taken up E. coli in an SB203580 (a p38 MAPK inhibitor)-sensitive manner. These findings indicate that glycine augments neutrophil microbicidal activity by enhancing azurophil granule-phagosome fusion via the GlyRα2/ROS/calcium/p38 MAPK pathway. We suggest that glycine could be a useful agent for increasing neutrophil bacterial clearance.

• Development and Reproduction
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• v.27 no.2
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• pp.77-89
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• 2023

Metformin is the most widely used anti-diabetic drug that helps maintain normal blood glucose levels primarily by suppressing hepatic gluconeogenesis in type II diabetic patients. We previously found that metformin induces apoptotic death in H4IIE rat hepatocellular carcinoma cells. Despite its anti-diabetic roles, the effect of metformin on hepatic de novo lipogenesis (DNL) remains unclear. We investigated the effect of metformin on hepatic DNL and apoptotic cell death in H4IIE cells. Metformin treatment stimulated glucose consumption, lactate production, intracellular fat accumulation, and the expressions of lipogenic proteins. It also stimulated apoptosis but reduced autophagic responses. These metformin-induced changes were clearly reversed by compound C, an inhibitor of AMP-activated protein kinase (AMPK). Interestingly, metformin massively increased the production of reactive oxygen species (ROS), which was completely blocked by compound C. Metformin also stimulated the phosphorylation of p38 mitogen-activated protein kinase (p38MAPK). Finally, inhibition of p38MAPK mimicked the effects of compound C, and suppressed the metformin-induced fat accumulation and apoptosis. Taken together, metformin stimulates dysregulated glucose metabolism, intracellular fat accumulation, and apoptosis. Our findings suggest that metformin induces excessive glucose-induced DNL, oxidative stress by ROS generation, activation of AMPK and p38MAPK, suppression of autophagy, and ultimately apoptosis.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1170-1178
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• 2008

The cyclopentenone prostaglandins (cyPGs) prostaglandin $A_1$ ($PGA_1$) and 15-deoxy-${\Delta}^{12,14}$-prostaglandin $J_2$ (15d-$PGJ_2$) have been reported to exhibit antiinflammatory activity in activated monocytes/macrophages. However, the effects of these two cyPGs on the expression of cytokine genes may differ. In this study, we investigated the mechanism of action of $PGA_1$ in lipopolysaccharide (LPS)-induced expression of inter leu kin (IL)-10 mRNA in mouse peritoneal macrophages. 15d-$PGJ_2$ inhibited expression of LPS-induced IL-10, whereas $PGA_1$ increased LPS-induced IL-10 expression. This synergistic effect of $PGA_1$ on LPS-induced IL-10 expression reached a maximum as early as 2 h after simultaneous $PGA_1$ and LPS treatment ($PGA_1$/LPS), and did not require new protein synthesis. The synergistic effect of $PGA_1$ was inhibited by GW9662, a specific peroxisome proliferator-activated receptor ${\gamma}(PPAR{\gamma})$ antagonist, and Bay-11-7082, a NF-${\kappa}B$ inhibitor. The extracellular signal-regulated kinases (ERK) inhibitor PD98059 increased the expression of $PGA_1$/LPS-induced IL-10 mRNA, rather than inhibiting the IL-10 expression. Moreover, $PGA_1$ inhibited LPS-induced ERK phosphorylation. The synergistic effect of $PGA_1$ on LPS-induced IL-10 mRNA and protein production was inhibited by p38 inhibitor PD169316, and $PGA_1$ increased LPS-induced p38 phosphorylation. In the case of stress-activated protein kinase/c-Jun $NH_2$-terminal kinase (SAPK/JNK), the SAPK/JNK inhibitor SP600125 did not inhibit IL-10 mRNA synthesis but inhibited the production of IL-10 protein remarkably. These results suggest that the synergistic effect of $PGA_1$ on LPS-induced IL-10 expression is NF-${\kappa}B$-dependent and mediated by mitogen-activated protein (MAP) kinases, p38, and SAPK/JNK signaling pathways, and also associated with the $PPAR{\gamma}$ pathway. Our data may provide more insight into the diverse mechanisms of $PGA_1$ effects on the expression of cytokine genes.

• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.33-37
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• 2014

Objective: Low intensity pulsed ultrasound (LIPUS) has been shown to accelerate cell proliferation and tissue healing in both animal models and clinical trials. However, details of the clinical effects of LIPUS have not been well characterized. The aim of this study was to investigate the effect of LIPUS on mitogen-activated protein kinase (MAPK) activation in rat articular chondrocytes. Design: Cross-sectional study. Methods: Chondrocyte were cultured in six well cell culture plates for 72 hours at $37^{\circ}C$ with 5% $CO_2$, and then exposed to LIPUS at 1.5 MHz frequency and $30-mW/cm^2$ power. Changes in chondrocyte activities were evaluated in response to oxydative stress in dose-dependent (0 and 300 uM) and time-dependent (0-24 hr) manner. The cell viability were analyzed using MTT [3-(4.5-dimethylthiazol-2-yl)-2.5 diphenyltetrazolium bromide]. The expression of p38 MAPK was measured using western blotting. Results: Oxidative stress was induced in rat chondrocytes using hydrogen peroxide ($H_2O_2$). The cell viability was decreased in chondrocytes after the $H_2O_2$ dose and time-dependent treatment. The p38 MAPK phosphorylation occurred at a significantly increased rate after $H_2O_2$ treated (p<0.05). Expression of p38 MAPK was decreased in the p38 inhibitor groups compared with the oxidative stress-induced chondrocyte damage via the p38 MAPK signaling pathways (p<0.05). Conclusions: It could be concluded that LIPUS can inhibit oxidative stress-induced chondrocyte damage via the p38 MAPK signaling pathways.