• 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.

• The Korean Journal of Food And Nutrition
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• v.28 no.4
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• pp.579-585
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• 2015

Rutin is a well-known flavonoid found in buckwheat. Recent studies have demonstrated that the biological actions of rutin include anti-inflammatory and anti-cancer effects, but the underlying molecular mechanisms of these actions are not yet fully understood. Neoplastic cell transformation is considered a major event that contributes to carcinogenesis, and the present study aimed to determine whether rutin would exert anti-tumor effects via the results suggest that rutin exerted a potent inhibitory influence on the molecular activity of the MEK/ERK and MKK4/JNK pathways and strongly attenuated EGF-induced neoplastic cell transformation. These findings provide insight into the biological actions of rutin and the molecular basis for the development of new chemoprotective agents.

• Archives of Reconstructive Microsurgery
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• v.14 no.2
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• pp.85-94
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• 2005

Purpose: This study was to evaluate the effect of ${\alpha}-lipoic$ acid, a potent free radical scavenger, on the expression of active form of extracellular signal-regulated kinase (pERK1/2) proteins from hindlimb muscles of rats following ischemia-reperfusion injury. Material and methods: 64 health, $280{\sim}350\;g$ weighted Sprague-Dawley male rats were used. In order to make a muscle flap, the gastrocnemius (GC) and soleus (SOL) muscles were dissected and elevated. The popliteal artery was occluded for 4hours and reperfused for 10 minutes, 30 minutes, 1 hour, 2 hours and 4 hours, respectively. Results: The ischemia by occlusion of the popliteal artery itself caused a minimal change in expression of phosphorylated form of proteins observed in hindlimb muscle. In contrast, after 4 hours of ischemia, immunoreactivity for pERK1/2 in the GC muscle showed dual peaks at 10 minutes and 4 hours after reperfusion. In ${\alpha}-lipoic$ acid treated group, the expression of pERK1/2 was increased significantly compared to I/R-only group. Conclusion: These results suggest that ${\alpha}-lipoic$ acid may protect I/R injury of the skeletal muscle through free radical scavening and activation of intracellular pERK1/2 expression.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2817-2819
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• 2011

• IMMUNE NETWORK
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• v.5 no.4
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• pp.237-246
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• 2005

Background: Little information is available on the identification and characterization of the upstream regulators of the signal transduction cascades for Mycobacterium tuberculosis (M. tbc)-induced ERK 1/2 activation and chemokine expression. We investigated the signaling mechanisms involved in expression of CCL3 /MIP-1 and CCL4/MIP-1 in human primary monocytes infected with M. tbc. Methods: MAP kinase phosphorylation was determined using western blot analysis with specific primary antibodies (ERK 1/2, and phospho-ERK1/2), and the upstream signaling pathways were further investigated using specific inhibitors. Results: An avirulent strain, M. tbc H37Ra, induced greater and more sustained ERK 1/2 phosphorylation, and higher CCL3 and CCL4 production, than did M. tbc H37Rv. Specific inhibitors for mitogen-activated protein kinase (MAPK) kinase (MEK; U0126 and PD98059) significantly inhibited the expression of CCL3 and CCL4 in human monocytes. Mycobactetia-mediated expression of CCL3 and CCL4 was not inhibited by the Ras inhibitor manumycin A or the Raf-1 inhibitor GW 5074. On the other hand, phospholipase C (PLC) inhibitor (U73122) and protein kinase C (PKC)specific inhibitors ($G\ddot{o}6976$ and Ro31-8220) significantly reduced M. tbc-induced activation of ERK 1/2 and chemokine synthesis. Conclusion: These results are the first to demonstrate that the PLC-PKC-MEK-ERK, not the Ras-Raf-MEK-ERK, pathway is the major signaling pathway inducing M. tbc-mediated CCL3 and CCL4 expression in human primary monocytes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.983-988
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• 2010

The present study aims to investigate a possible mechanism of electroacupuncture (EA) in the spinal dorsal horn that may underlie N-methyl-D-aspartate (NMDA) receptor-associated extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathways. The hot plate latency of the ipsilateral hindpaw of EA-treated rats was significantly decreased compared with complete Freund's adjuvant (CFA)-injected ones. The expressions of NR1 and NR2B subuint mRNA of NMDA receptor in the whole L4-5 segments are decreased by CFA treatment, but NR2B subunit was significantly recovered by EA treatment. When we detected the expression of ERK, there were no significant difference between normal and CFA-treated rats with EA or NMDA receptor antagonist MK801. But phosphorylated ERK expressions were markedly induced by CFA, but these inductions were significantly modulated by EA treatment. Although hosphorylation of ERK was also arrested by MK801, these inductions of CFA-injected rats was markedly inhibited only by co-treatment with EA and MK801. Phosphorylated cAMP response element-binding protein (CREB), ERK-related transcriptional factor, showed a significant increase in CFA-treated rats and this increase was slightly inhibited by EA and MK801 treatments. But immunoreaction for phosphorylated CREB were significantly increased by CFA treatment in the superficial laminae of the dorsal horn and these inductions were significantly arrested by co-treatment of EA and MK801. Consequently, the hyperalgesia induced by CFA are associated NMDA receptor and EA and MK801 may showed anti-hyperalgesia via same mechanism for inhibition of ERK and CREB phosphorylation in the dorsal horn.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.2
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• pp.115-123
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• 2006

Objective: To investigate new signal transduction cascade through integrin, FAK and ERK in the suppressed cell proliferation by GnRH-I and -II. Method: Human endometrial cancer cells (HEC1A) were cultured under the following condition: DMEM/F12 (10% FBS). GnRH-I and -II were treated time (0, 5, 10, 15, 20, 30 min; 100 nM) and dose (10 nM or 100 nM; 20 min) dependent manner according to experimental purposes. Cell proliferation was measured using [$^3H$] thymidine incorporation assay. Immunoblotting was utilized to detect proteins. Results: GnRH-I and -II inhibited proliferation of HEC1A cells and induced expression of integrin ${\beta}3$. Phosphorylation of FAK and ERK were induced by GnRH-I and -II. Conclusion: GnRH inhibited cell proliferation via the expression of integrin and FAK, ERK phosphorylation.

• Journal of Life Science
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• v.13 no.6
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• pp.849-855
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• 2003

Nitric oxide (NO) plays an important role as a signaling molecule in the proliferation of placenta trophoblasts. In this study, we investigated the effect of NO on the activation of phospholipase C (PLC) in BeWo cells, choriocar-cinoma cell line. Sodium nitroprusside (SNP), an agent to produce NO spontaneously in cells, alone increased $［^3H］$ thymidine incorporation of BeWo cells, indicating NO stimulates proliferation of the cells. NO-induced proliferation of BeWo cells was blocked by U73122, an inhibitor of PLC, suggesting that NO-induced PLC activation is involved in the cell proliferation. NO also stimulated extracellular signal-regulated kinase (ERK) in BeWo cells, indicated by increased phosphorylation of ERK1/2 in Western blotting using anti-phospho-ERK1/2 antibody. NO-induced phos-phorylation of ERK1/2 was not abrogated by U73122. $PLC\gamma_1$l but not$PLC\gamma_2$ was tyrosine phosphorylated by SNP in immunoprecipitation assay using anti-$PLC\gamma_1$/$PLC\gamma_2$ antibodies, and SNP-induced phosphorylation of $PLC\gamma_1$ was abrogated by pre-treatment of cells with genistein and PD98059, indicating that NO induced-phosphorylation of $PLC\gamma_1$ is mediated by ERK. These results suggest that NO stimulates the proliferation of BeWo cells through ERK and $PLC\gamma_1$.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.647-652
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• 2021

In this study, Saussurea Lappa roots were extracted using ethanol and n-hexane, and also the effects on proliferation of human hair dermal papilla cells and fibroblast and related signaling pathway were evaluated. 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide (MTT) assay was conducted for cell proliferation effect of Saussurea Lappa root extract, and extracellular signal-related kinase (ERK), serine/threonine protein kinase (Akt), wingless-related integration site (Wnt)/𝛽-catenin signaling pathway, and 5𝛼-reductase expression through western blot analysis were measured. Saussurea Lappa root extract significantly increased human hair dermal papilla cells and propagation of fibroblast, promoted phosphorylation of ERK and Akt that get involved in cell proliferation. Additionally, Saussurea Lappa root extract significantly decreased promotion of Akt phosphorylation and cell proliferation by MEK/ERK inhibitor PD98059 and PI3K/Akt inhibitor LY294002. Also, Saussurea Lappa root extract induced intranuclear 𝛽-catenin accumulation by promoting phosphorylation of 𝛽-catenin (Ser552, 675) through phosphorylation of GSK-3𝛽 (Ser9), and suppressed activation of 5𝛼-reductase type I and II. Overall, Saussurea Lappa root induces cell proliferation through vitalization of ERK and Akt route of human hair dermal papilla cells and fibroblast and apoptosis defense mechanism, and can be helpful in hair loss prevention and hair growth by vitalizing the 𝛽-catenin signaling pathway and inhibiting activation of 5𝛼-reductase, which can be used as a potential hair care products.

• BMB Reports
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• v.34 no.1
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• pp.85-89
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• 2001

Both topoisomerase $II{\alpha}$ and $II{\beta}$ east as phosphoproteins in the cells. Recently it was reported that DNA topoisomerase $II{\alpha}$ associates with and is phosphorylated by the extracellular signal-regulated kinase 2 (ERK2). Also, ERK2 stimulates the activity of topoisomerase II by a phosphorylation-independent manner [Shapiro et al., (1999) Mol. Cell. Biol. 19, 3551-3560]. In this study, a yeast two-hybrid system was used to investigate the binding site between topoisomerase $II{\alpha}$ or $II{\beta}$ and ERK2. The two-hybrid test clearly showed that topoisomerase $II{\beta}$ residues 1099-1263, and topoisomerase $II{\alpha}$ residues 1078-1182, mediate the interaction with ERK2, and that the leucine zipper motifs of topoisomerase $II{\alpha}$ and $II{\beta}$ are not required for its physical binding to ERK2. Our results suggest that topoisomerase $II{\beta}$ residues 1099-1263, and topoisomerase $II{\alpha}$ residues 1078-1182, may be common binding sites for activator proteins.