• Molecules and Cells
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• v.39 no.3
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• pp.266-279
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• 2016

The mechanism by which 12-O-tetradecanoylphorbol-13-acetate (TPA) bypasses cellular senescence was investigated using human diploid fibroblast (HDF) cell replicative senescence as a model. Upon TPA treatment, protein kinase C (PKC) ${\alpha}$ and $PKC{\beta}1$ exerted differential effects on the nuclear translocation of cytoplasmic pErk1/2, a protein which maintains senescence. $PKC{\alpha}$ accompanied pErk1/2 to the nucleus after freeing it from $PEA-15pS^{104}$ via $PKC{\beta}1$ and then was rapidly ubiquitinated and degraded within the nucleus. Mitogen-activated protein kinase docking motif and kinase activity of $PKC{\alpha}$ were both required for pErk1/2 transport to the nucleus. Repetitive exposure of mouse skin to TPA downregulated $PKC{\alpha}$ expression and increased epidermal and hair follicle cell proliferation. Thus, $PKC{\alpha}$ downregulation is accompanied by in vivo cell proliferation, as evidenced in 7, 12-dimethylbenz(a)anthracene (DMBA)-TPA-mediated carcinogenesis. The ability of TPA to reverse senescence was further demonstrated in old HDF cells using RNA-sequencing analyses in which TPA-induced nuclear $PKC{\alpha}$ degradation freed nuclear pErk1/2 to induce cell proliferation and facilitated the recovery of mitochondrial energy metabolism. Our data indicate that TPA-induced senescence reversal and carcinogenesis promotion share the same molecular pathway. Loss of $PKC{\alpha}$ expression following TPA treatment reduces pErk1/2-activated SP1 biding to the $p21^{WAF1}$ gene promoter, thus preventing senescence onset and overcoming G1/S cell cycle arrest in senescent cells.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1657-1662
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• 2012

Fucosyltransferase IV (FUT4) has been implicated in cell adhesion, motility, and tumor progression in human epidermoid carcinoma A431 cells. We previously reported that it promotes cell proliferation through the ERK/MAPK and PI3K/Akt signaling pathways; however, the molecular mechanisms underlying FUT4-induced cell invasion remain unknown. In this study we determined the effect of FUT4 on expression of matrix metalloproteinase (MMP)-12 induced by EGF in A431 cells. Treatment with EGF resulted in an alteration of cell morphology and induced an increase in the expression of MMP-12. EGF induced nuclear translocation of nuclear factor kB (NF-${\kappa}B$) and resulted in phosphorylation of $IkB{\alpha}$ in a time-dependent manner. In addition, ERK1/2 and p38 MAPK were shown to play a crucial role in mediating EGF-induced NF-${\kappa}B$ translocation and phosphorylation of $I{\kappa}B{\alpha}$ when treated with the MAPK inhibitors, PD98059 and SB203580, which resulted in increased MMP-12 expression. Importantly, we showed that FUT4 up-regulated EGF-induced MMP-12 expression by promoting the phosphorylation of ERK1/2 and p38 MAPK, thereby inducing phosphorylation/degradation of $I{\kappa}B{\alpha}$, NF-${\kappa}B$ activation. Base on our data, we propose that FUT4 up-regulates expression of MMP-12 via a MAPK-NF-${\kappa}B$-dependent mechanism.

• BMB Reports
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• v.45 no.4
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• pp.247-252
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• 2012

Although previous studies have demonstrated that BMP9 is highly capable of inducing osteogenic differentiation of mesenchymal stem cells, the molecular mechanism involved remains to be fully elucidated. In this study, we showed that BMP9 simultaneously promotes the activation of Smad1/5/8, p38 and ERK1/2 in C3H10T1/2 cells. Knockdown of Smad4 with RNA interference reduced nuclear translocation of Smad1/5/8, and disrupted BMP9-induced osteogenic differentiation. BMP9-induced osteogenic differentiation was blocked by p38 inhibitor SB203580, whereas enhanced by ERK1/2 inhibitor PD98059. SB203580 decreased BMP9-activated Smads singling, and yet PD98059 stimulated Smads singling in C3H10T1/2 cells. The effects of inhibitor were reproduced with adenovirus expressing siRNA targeted p38 and ERK1/2, respectively. Taken together, our findings revealed that Smads, p38 and ERK1/2 are involved in BMP9-induced osteogenic differentiation. Also, it is noteworthy that p38 and ERK1/2 may play opposing regulatory roles in mediating BMP9-induced osteogenic differentiation of C3H10T1/2 cells.

• BMB Reports
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• v.49 no.4
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• pp.220-225
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• 2016

Cancer cells have different characteristics due to the genetic differences where these unique features may strongly influence the effectiveness of therapeutic interventions. Here, we show that the spontaneous reactivation of extracellular signalregulated kinase (ERK), distinct from conventional ERK activation, represents a potent mechanism for cancer cell survival. We studied ERK1/2 activation in vitro in SW480 colorectal cancer cells. Although ERK signaling tends to be transiently activated, we observed the delayed reactivation of ERK1/2 in epidermal growth factor (EGF)-stimulated SW480 cells. This effect was observed even after EGF withdrawal. While phosphorylated ERK1/2 translocated into the nucleus following its primary activation, it remained in the cytoplasm during late-phase activation. The inhibition of primary ERK1/2 activation or protein trafficking, blocked reactivation and concurrently increased caspase 3 activity. Our results suggest that the biphasic activation of ERK1/2 plays a role in cancer cell survival; thus, regulation of ERK1/2 activation may improve the efficacy of cancer therapies that target ERK signaling.

• Korean Journal of Plant Resources
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• v.27 no.3
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• pp.209-214
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• 2014

In this study, we investigated whether A. distichum decreases the production of inflammatory mediators through downregulation of the NF-${\kappa}B$ and ERK pathway. Our data indicated that A. distichum leaf inhibits the overexpression of iNOS in protein and mRNA levels, and subsequently blocked LPS-mediated NO overproduction in RAW264.7 cells. A. distichum leaf inhibited $I{\kappa}B-{\alpha}$ degradation and p65 nuclear translocation, and subsequently suppressed transcriptional activity of NF-${\kappa}B$ in LPS-stimulated RAW264.7 cells. In addition, A. distichum leaf suppressed LPS-induced ERK1/2 activation by decreasing phosphorylation of ERK1/2. These findings suggest that A. distichum leaf shows anti-inflammatory activities through suppressing ERK-mediated NF-${\kappa}B$ activation in mouse macrophage.

• The Journal of Korean Medicine
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• v.41 no.4
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• pp.52-63
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• 2020

Objectives: In this study, we investigated the effects of Pueraria lobata Ohwi flower extracts (PLFE) on macrophages and their underlying mechanism(s) of action. PLFE increased the production of NO and cytokines (IL-6 and TNF-𝛼) in a dose-dependent manner, indicating its immunostimulatory property. Furthermore, PLFE upregulated iNOS, COX-2, and mitogen-activated protein kinase (MAPK) signaling in RAW264.7 cells. Additionally, PLFE enhanced the phosphorylation of I𝜅B𝛼 and subsequent I𝜅B𝛼 degradation, thereby enabling the nuclear translocation of NF-𝜅B. Taken together, these findings demonstrate that the immunostimulatory effects of PLFE are mediated by the nuclear translocation of the p65 subunit of NF-𝜅B and subsequent secretion of cytokines (IL-6 and TNF-𝛼), upregulation of iNOS and COX-2, and stimulation of MAPK signaling (JNK, ERK, and p38). Thus, PLFE may be a potential immunostimulatory therapeutic.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.85-92
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• 2020

One of the omega-3 essential fatty acids, docosahexaenoic acid (DHA), is a significant constituent of the cell membrane and the precursor of several potent lipid mediators. These mediators are considered to be important in preventing or treating several diseases. Resolvin D5, an oxidized lipid mediator derived from DHA, has been known to exert anti-inflammatory effects. However, the detailed mechanism underlying these effects has not yet been elucidated in human monocytic THP-1 cells. In the present study, we investigated the effects of resolvin D5 on inflammation-related signaling pathways, including the extracellular signal-regulated kinase (ERK)-nuclear factor (NF)-κB signaling pathway. Resolvin D5 downregulated the production of interleukin (IL)-6 and chemokine (C-C motif) ligand 5 (CCL5). Additionally, these inhibitory effects were found to be modulated by mitogen-activated protein kinase (MAPK) and NF-κB in lipopolysaccharide (LPS)-treated THP-1 cells. Resolvin D5 inhibited the LPS-stimulated phosphorylation of ERK and translocation of p65 and p50 into the nucleus, resulting in the inhibition of IL-6 and CCL5 production. These results revealed that resolvin D5 exerts anti-inflammatory effects in LPS-treated THP-1 cells by regulating the phosphorylation of ERK and nuclear translocation of NF-κB.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.92-92
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• 2018

Solanum nigrum L. (SNL), generally known as black nightshade, is traditionally used as medicine to reduce inflammation caused by several diseases like asthma, chronic bronchitis and liver cirrhosis. In this study, anti-inflammatory effects of SNL extract were examined and possible molecular mechanisms of the anti-inflammatory effects were investigated. The inhibitory effects of SNL extract on nitric oxide (NO), pro-inflammatory cytokines ($TNF-{\alpha}$, IL-6) and Matrix metallopeptidase 9 (MMP-9) productions were dissected using lipopolysaccharide (LPS) stimulated murine macrophage-like cell line Raw264.7 cells and human microglial cell line BV2 cells. We further investigated whether SNL extract could suppress the phosphorylation of ERK1/2, JNK, and p38 and the nuclear expression of nuclear factor $NF-{\kappa}B$ p65 in LPS-stimulated Raw264.7 cells and BV2 cells. As a result, we showed that the SNL extract significantly decreased the production of pro-inflammatory cytokines, NO, and MMP-9. In addition, the SNL strongly inhibited the phosphorylation of ERK1/2, JNK, p38 and nuclear translocation of $NF-{\kappa}B$ p65 in activated cells. We confirmed that the extracts of SNL effectively inhibits the anti-inflammatory and may be used as a therapeutic to various inflammatory diseases.

• Korean Journal of Plant Resources
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• v.31 no.3
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• pp.202-210
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• 2018

Abeliophyllum distichum is a medicinal plant used in regional traditional medicine to relieve pain in inflammatory processes. In this study, anti-inflammatory effects of Abeliophyllum distichum flower (ADF) extract were examined. Furthermore, possible molecular mechanisms of the anti-inflammatory effects were dissected. The anti-inflammatory activity was investigated by inhibition of lipopolysaccharide (LPS) induced pro-inflammatory cytokine production in murine macrophage-like cell line Raw264.7 cells. The measurement of the induced pro-inflammatory cytokine levels were carried out by ELISA. The phosphorylation of ERK1/2, JNK, and MAPK, and the nuclear expression of nuclear factor NF-${\kappa}B$ p65 were investigated by Western blot analysis. The extract of ADF significantly decreased the production of pro-inflammatory cytokines. In addition, the extract suppressed the phosphorylation of ERK1/2, JNK, and p38 MAPK, and the nuclear translocation of NF-${\kappa}B$ p65 in activated cells. Our findings provide evidence for the popular use of Abeliophylli distichum in inflammation around Goesan region and also suggest that the flower extract has potential therapeutic benefits against various inflammatory diseases.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.89-89
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• 2018

Abeliophyllum distichum is a medicinal plant used in regional traditional medicine to relieve pain in inflammatory processes. In this study, anti-inflammatory effects of Abeliophyllum distichum stem (ADS) ethyl acetate extract were examined. Furthermore, possible molecular mechanisms of the anti-inflammatory effects were dissected. The anti-inflammatory activity was investigated by inhibition of lipopolysaccharide (LPS) induced pro-inflammatory cytokine production in murine macrophage-like cell line Raw264.7 cells and human microglial cell line BV2 cells. The measurement of the induced pro-inflammatory cytokine levels were carried out by ELISA. The phosphorylation of ERK1/2, JNK, and MAPK, and the nuclear expression of nuclear factor $NF-{\kappa}B$ p65 were investigated by Western blot analysis. The extract of ADS significantly decreased the production of pro-inflammatory cytokines. In addition, the extract suppressed the phosphorylation of ERK1/2, JNK, and p38 MAPK, and the nuclear translocation of $NF-{\kappa}B$ p65 in activated cells. Our findings provide evidence for the popular use of Abeliophylli distichum in inflammation around Goesan region and also suggest that the stem extract has potential therapeutic benefits against several inflammatory diseases.