• Biomolecules & Therapeutics
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• 제20권2호
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• pp.165-170
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• 2012

Cell migration plays a role in many physiological and pathological processes. Reactive oxygen species (ROS) produced in mammalian cells influence intracellular signaling processes which in turn regulate various biological activities. Here, we investigated whether melanoma cell migration could be controlled by ROS production under normoxia condition. Cell migration was measured by wound healing assay after scratching confluent monolayer of B16F10 mouse melanoma cells. Cell migration was enhanced over 12 h after scratching cells. In addition, we found that ROS production was increased by scratching cells. ERK phosphorylation was also increased by scratching cells but it was decreased by the treatment with ROS scavengers, N-acetylcysteine (NAC). Tumor cell migration was inhibited by the treatment with PD98059, ERK inhibitor, NAC or DPI, well-known ROS scavengers. Tumor cell growth as judged by succinate dehydrogenase activity was inhibited by NAC treatment. When mice were intraperitoneally administered with NAC, the intracellular ROS production was reduced in peripheral blood mononuclear cells. In addition, B16F10 tumor growth was significantly inhibited by in vivo treatment with NAC. Collectively, these findings suggest that tumor cell migration and growth could be controlled by ROS production and its downstream signaling pathways, in vitro and in vivo.

• Journal of Microbiology and Biotechnology
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• 제26권6호
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• pp.1063-1066
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• 2016

Longan (Dimocarpus longan Lour.) has been used as a traditional oriental medicine and possesses a number of physiological activities. In this study, we used cell-based herbal extract screening to identify longan fruit extract (LFE) as an activator of osteoblast differentiation. LFE up-regulated alkaline phosphatase (ALP) activity, induced mineralization, and activated Runx2 gene expression in MC3T3-E1 cells. Furthermore, treatment of MC3T3-E1 cells with LFE promoted the phosphorylation of extracellular signal-regulated kinase1/2 (Erk1/2); however, abrogation of Erk1/2 activation with PD98059 resulted in down-regulation of the phospho-SMAD1/5/8 and Runx2 levels, which in turn reduced the ALP activity. Our findings suggest that LFE exerts its osteogenic activity through activation of the ERK signaling pathway and may have potential as an herbal therapeutic or a preventive agent for the treatment of osteoporosis.

• The Korean Journal of Physiology and Pharmacology
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• 제19권1호
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• pp.29-34
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• 2015

Fucoidan, a fucose-rich sulfated polysaccharide derived from brown seaweed in the class Phaeophyceae, has been widely studied for its possible health benefits. However, the potential of fucoidan as a possible treatment for hyperpigmentation is not fully understood. This study investigated the effects of fucoidan on melanogenesis and related signaling pathways using Mel-Ab cells. Fucoidan significantly decreased melanin content. While fucoidan treatment decreased tyrosinase activity, it did not do so directly. Western blot analysis indicated that fucoidan downregulated microphthalmia-associated transcription factor and reduced tyrosinase protein expression. Further investigation showed that fucoidan activated the extracellular signal-regulated kinase (ERK) pathway, suggesting a possible mechanism for the inhibition of melanin synthesis. Treatment with PD98059, a specific ERK inhibitor, resulted in the recovery of melanin production. Taken together, these findings suggest that fucoidan inhibits melanogenesis via ERK phosphorylation.

• Molecular & Cellular Toxicology
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• 제2권1호
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• pp.15-20
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• 2006

Genistein is a potent, plant-derived isoflavone that displays estrogenic activity at low concentrations but inhibits proliferation at high amounts. However, the molecular mechanism of genistein is not completely understood. In the present study, the biphasic effects (estrogenic and antiestrogenic activity) of genistein on the growth of MCF-7 cells were identified. Genistein within a low range of concentration, $1-10\;{\mu}M$, stimulated proliferation, while $50-100\;{\mu}M$ caused apoptotic cell death. Additionally, genistein at a low concentration induced estrogen receptor (ER)-mediated gene expression and ER phosphorylation. When pre-treated with PD98059, an MEK inhibitor, ER-mediated gene expression and ER phosphorylation by genistein were noticeably increased. However, the increased gene expression and phosphorylation did not enhance cell proliferation. Moreover, it was observed that ER-mediated signaling performs an important role in the MAPK pathway. The proliferation and apoptosis in genistein-treated MCF-7 cells were partially dependent on the Bcl-2 level. The addition of IC1 182, 780, an estrogen receptor antagonist, inhibited Bcl-2 expression induced by genistein. This study suggests that there is a close relationship between Bcl-2 and the ER signaling pathways in MCF-7 cells.

• Molecules and Cells
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• 제40권5호
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• pp.371-377
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• 2017

Despite the importance of the receptor activator of nuclear factor (NF)-kappaB ligand (RANKL)-RANK signaling mechanisms on osteoclast differentiation, little has been studied on how RANK expression is regulated or what regulates its expression during osteoclastogenesis. We show here that insulin signaling increases RANK expression, thus enhancing osteoclast differentiation by RANKL. Insulin stimulation induced RANK gene expression in time- and dose-dependent manners and insulin receptor shRNA completely abolished RANK expression induced by insulin in bone marrow-derived monocyte/macrophage cells (BMMs). Moreover, the addition of insulin in the presence of RANKL promoted RANK expression. The ability of insulin to regulate RANK expression depends on extracellular signal-regulated kinase 1/2 (ERK1/2) since only PD98059, an ERK1/2 inhibitor, specifically inhibited its expression by insulin. However, the RANK expression by RANKL was blocked by all three mitogen-activated protein (MAP) kinases inhibitors. The activation of RANK increased differentiation of BMMs into tartrate-resistant acid phosphatase-positive ($TRAP^+$) osteoclasts as well as the expression of dendritic cell-specific transmembrane protein (DC-STAMP) and d2 isoform of vacuolar ($H^+$) ATPase (v-ATPase) Vo domain (Atp6v0d2), genes critical for osteoclastic cell-cell fusion. Collectively, these results suggest that insulin induces RANK expression via ERK1/2, which contributes to the enhancement of osteoclast differentiation.

• Archives of Pharmacal Research
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• 제28권12호
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• pp.1337-1340
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• 2005

A lignan derivative, (-)-(7R, 8S)-dihydrodehydrodiconiferyl alcohol (DHDA), was isolated from Kalopanax septemlobus L. and was observed to have neuritogenic activity. DHDA at 50 $\mu$M caused a marked induction of neurite outgrowth and an enhancement of nerve growth factor (NGF)-mediated neurite outgrowth from PC12 cells. However, it did not exhibit any neurotrophic action. At 50 $\mu$M, DHDA enhanced NGF-induced neurite-bearing activity. This activity was partially blocked by the mitogen-activated protein kinase (MAPK) inhibitor PD98059 and by GF109203X, a protein kinase C (PKC) inhibitor. These results suggest that DHDA can induce neurite outgrowth and enhance NGF-induced neurite outgrowth from PC12 cells by amplifying up-stream steps such as MAPK and PKC.

• The Journal of Internal Korean Medicine
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• 제31권2호
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• pp.254-263
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• 2010

Objectives : The neuroprotective effects of bee venom (BV) have been demonstrated in many studies, but bee venom has many side effects. So we used sweet bee venom (SBV), which has high molecular elements removed to reduce the side effects. I examined the neuroprotective effect of sweet bee venom in 1-methyl-4-phenylpyridine ($MPP^+$)-induced human neuroblastoma SH-SY5Y cells. Methods : To observe the possible toxicity of SBV itself, SH-SY5Y cells were treated with SBV in various concentrations for 3 h and $MPP^+$ in concentrations (1 and 5mM) for 24h. To investigate the protective effect of SBV against $MPP^+$ toxicity, SH-SY5Y cells were pretreated with vehicle or nontoxic concentrations of SBV for 3h and the cells were not washed, followed by incubation with respective concentrations of SBV and 1 mM $MPP^+$ for 24h. To investigate the protective effect of SBV against $MPP^+$ toxicity, SH-SY5Y cells were pretreated with vehicle or nontoxic concentrations of SBV for 3h and the cells were not washed, followed by incubation with respective of SBV(0.5%), 1 mM $MPP^+$, 5uM AKT inhibitor(LY984002) and 10uM ERK inhibitor(PD98059) for 24 h. The protective effect was measured by cell viability assay. To investigate the degree of apoptosis, caspase-3 enzyme activity was measured in control, $MPP^+$, SBV+$MPP^+$. Results : SBV (0.5%) pretreatment protected the SH-SY5Y cells against $MPP^+$-induced apoptotic cell death. The cell viability was higher in the SH-SY5Y cells that were pretreated with vehicle or nontoxic concentrations of SBV than those not pretreated. The caspase-3 activity was lower in the pretreated groups than these not pretreated. ERK and AKT enzymes have a role in the neuroprotective effects of the sweet bee venom. Conclusions : The results demonstrate that SBV has a protective effect on dopaminergic neurons against $MPP^+$ toxicity. This data suggest that SBV could be a potential therapeutic tool for neurodegenerative diseases such as Parkinson's disease(PD).

• BMB Reports
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• 제46권5호
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• pp.258-263
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• 2013

In the current study, we explored the effect of LDR on the activation of Nrfs transcription factor involved in cellular redox events. Experiments were carried out utilizing 0.05 and 0.5 Gy X-ray irradiated normal human skin fibroblast HS27 cells. The results showed LDR induced Nrf1 and Nrf2 activation and expression of antioxidant genes HO-1, Mn-SOD, and NQO1. In particular, 0.05 Gy-irradiation increased only Nrf1 activation, but 0.5 Gy induced both Nrf1 and Nrf2 activation. LDR-mediated Nrf1/2 activation was accompanied by reactive species (RS) generation and $Ca^{2+}$ flux. This effect was abolished in the presence of N-acetyl-cysteine and BAPTA- AM. Furthermore, Nrf1/2 activation by LDR was suppressed by PD98059, an inhibitor of ERK1/2. In conclusion, LDR induces Nrf1 and Nrf2 activation and expression of Nrf-regulated antioxidant defense genes through RS and $Ca^{2+}$/ERK1/2 pathways, suggesting new insights into the molecular mechanism underlying the beneficial role of LDR in HS27 cells.

• Journal of Ginseng Research
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• 제39권3호
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• pp.238-242
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• 2015

Background: Panax ginseng has been used to prolong longevity and is believed to be useful for improving skin complexion. Ginsenosides are the most active components isolated from ginseng, and ginsenoside Rg3 (G-Rg3) in particular has been demonstrated to possess antioxidative, antitumorigenic, and anti-inflammatory properties. The aim of this study was to examine the ability of G-Rg3 to inhibit melanogenesis. Methods: The effects of G-Rg3 on melanin contents and the protein levels of tyrosinase, microphthalmia-associated transcription factor (MITF), and tyrosinase-related protein 1 (TRP1) were evaluated. Melanogenesis-regulating signaling molecules such as Akt and extracellular signal-regulated kinase (ERK) were also examined to explore G-Rg3-induced antimelanogenic mechanisms. Results: G-Rg3 was found to significantly inhibit the synthesis of melanin in normal human epidermal melanocytes and B16F10 cells in a dose-dependent manner. The activity of cellular tyrosinase and the expression of MITF, tyrosinase, and TRP1 were all reduced, whereas ERK was strongly activated. PD98059 (a specific inhibitor of ERK) attenuated the G-Rg3-induced inhibition of melanin synthesis and tyrosinase activity. Conclusion: Taken together, these results showed that G-Rg3 induces the activation of ERK, which accounts for its antimelanogenic effects. G-Rg3 may be a promising safe skin-whitening agent, adding to the long list of uses of P. ginseng for the enhancement of skin beauty.

• Korean Journal of Plant Resources
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• 제31권3호
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• pp.218-227
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• 2018

In this study, we investigated the effect of the extracts from Vaccinium oldhamii on cell proliferation and the regulatory mechanisms of cyclin D1 protein level in human cancer cells. The branch extracts from Vaccinium oldhamii (VOB) showed higher inhibitor effect against the cell growth than leave extracts (VOL) and fruit extracts (VOF) in human colorectal cancer, breast cancer, prostate cancer, non-small lung cancer, pancreatic cancer and liver cancer cells. In addition, VOB decreased cyclin D1 level at both protein and mRNA level. MG132 treatment attenuated VOB-mediated cyclin D1 downregulation. A point mutation of threonine-286 to alanine attenuated cyclin D1 degradation by VOB. In addition, the inhibition of nuclear export by leptomycin B (LMB) attenuated cyclin D1 degradation by VOB. But, the treatment of PD98059 (ERK1/2 inhibitor), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor), LiCl ($GSK3{\beta}$ inhibitor), LY294002 (PI3K inhibitor) or BAY 11-7082 ($I{\kappa}K$ inhibitor) did not affect VOB-induced cyclin D1 degradation. In conclusion, VOB induced cyclin D1 degradation through redistribution of cyclin D1 from the nucleus to cytoplasm via T286 phosphorylation of cyclin D1, which resulted in the inhibition of cancer cell proliferation.