• BMB Reports
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• v.36 no.5
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• pp.468-474
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• 2003

The molecular mechanism of hypoxia-induced apoptosis has not been clearly elucidated. In this study, we investigated the involvement of extracellular signal-regulated protein kinase (ERK 1/2) in hypoxia-induced apoptosis using cobalt chloride in HeLa human cervical cancer cells. The cobalt chloride was used for the induction of hypoxia, and its $IC_{50}$ was $471.4\;{\mu}M$. We demonstrated the DNA fragmentation after incubation with concentrations more than $50\;{\mu}M$ cobalt chloride for 24 h, and also evidenced the morphological changes of the cells undergoing apoptosis with electron microscopy. Next, we examined the signaling pathway of cobalt chloride-induced apoptosis in HeLa cells. ERK1/2 activation occurred 6 and 9 h after treatment with $600\;{\mu}M$ cobalt chloride. Meanwhile, the pretreatment of the MEK 1 inhibitor (PD98059) completely blocked the cobalt chloride-induced ERK 1/2 activation. At the same time, the activated ERK 1/2 translocated into the nucleus and phosphorylated its transcriptional factor, c-Jun. In addition, the pretreatment of PD98059 inhibited the cobalt chloride-induced DNA fragmentation and apoptotic cell death. These results suggest that cobalt chloride is able to induce apoptotic activity in HeLa cells, and its apoptotic mechanism may be associated with signal transduction via ERK 1/2.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.307-314
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• 2013

Connective tissue growth factor (CTGF) is a potent pro-fibrotic factor, which is implicated in fibrosis through extracellular matrix (ECM) induction in diabetic cardiovascular complications. It is an important downstream mediator in the fibrotic action of transforming growth factor ${\beta}$ ($TGF{\beta}$) and is potentially induced by hyperglycemia in human vascular smooth muscle cells (VSMCs). Therefore, the goal of this study is to identify the signaling pathways of CTGF effects on ECM accumulation and cell proliferation in VSMCs under hyperglycemia. We found that high glucose stimulated the levels of CTGF mRNA and protein and followed by VSMC proliferation and ECM components accumulation such as collagen type 1, collagen type 3 and fibronectin. By depleting endogenous CTGF we showed that CTGF is indispensable for the cell proliferation and ECM components accumulation in high glucose-stimulated VSMCs. In addition, pretreatment with the MEK1/2 specific inhibitors, PD98059 or U0126 potently inhibited the CTGF production and ECM components accumulation in high glucose-stimulated VSMCs. Furthermore, knockdown with ERK1/2 MAPK siRNA resulted in significantly down regulated of CTGF production, ECM components accumulation and cell proliferation in high glucose-stimulated VSMCs. Finally, ERK1/2 signaling regulated Egr-1 protein expression and treatment with recombinant CTGF reversed the Egr-1 expression in high glucose-induced VSMCs. It is conceivable that ERK1/2 MAPK signaling pathway plays an important role in regulating CTGF expression and suggests that blockade of CTGF through ERK1/2 MAPK signaling may be beneficial for therapeutic target of diabetic cardiovascular complication such as atherosclerosis.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6391-6395
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• 2014

Overexpression of aquaporins (AQPs) has been reported in several human cancers. Epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinases 1/2 (Erk1/2) are associated with tumorigenesis and cancer progression and may upregulate AQP expression. In this study, we demonstrated that EGF (epidermal growth factor) induces SiHa cells migration and AQP8 expression. Wound healing results showed that cell migration was increased by 2.79-1.50-fold at 24h and 48h after EGF treatment. AQP8 expression was significantly increased (3.33-fold) at 48h after EGF treatment in SiHa cells. An EGFR kinase inhibitor, PD153035, blocked EGF-induced AQP8 expression and cell migration and AQP8 expression was decreased from 1.59-fold (EGF-treated) to 0.43-fold (PD153035-treated) in SiHa. Furthermore, the MEK (MAPK (mitogen-activated protein kinase)/Erk (extracellular signal regulated kinase)/Erk inhibitor U0126 also inhibited EGF-induced AQP8 expression and cell migration. AQP8 expression was decreased from 1.21-fold (EGF-treated) to 0.43-fold (U0126-treated). Immunofluorescence microscopy further confirmed the results. Collectively, our findings show that EGF induces AQP8 expression and cell migration in human cervical cancer SiHa cells via the EGFR/Erk1/2 signal transduction pathway.

• Molecules and Cells
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• v.21 no.2
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• pp.237-243
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• 2006

Brain-derived neurotrophic factor (BDNF) is a neuromodulator of nociceptive responses in the dorsal root ganglia (DRG) and spinal cord. BDNF synthesis increases in response to nerve growth factor (NGF) in trkA-expressing small and medium-sized DRG neurons after inflammation. Previously we demonstrated differential activation of multiple BDNF promoters in the DRG following peripheral nerve injury and inflammation. Using reporter constructs containing individual promoter regions, we investigated the effect of NGF on the multiple BDNF promoters, and the signaling pathway by which NGF activates these promoters in PC12 cells. Although all the promoters were activated 2.4-7.1-fold by NGF treatment, promoter IV gave the greatest induction. The p38 mitogen-activated protein kinase (MAPK) inhibitor, SB203580, phosphatidylinositol 3-kinase (PI-3K) inhibitor, LY294003, protein kinase A (PKA) inhibitor, H89, and protein kinase C (PKC) inhibitor, chelerythrine, had no effect on activation of promoter IV by NGF. However, activation was completely abolished by the MAPK kinase (MEK) inhibitors, U0126 and PD98059. In addition, these inhibitors blocked NGF-induced phosphorylation of extracellular signal-regulated protein kinase (ERK) 1/2. Taken together, these results suggest that the ERK1/2 pathway activates BDNF promoter IV in response to NGF independently of NGF-activated signaling pathways involving PKA and PKC.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.503-509
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• 2018

In this study, a Proton-Transfer Reaction-Time-of-Flight Mass spectrometer (PTR-TOF-MS) was used for the continuous monitoring of Volatile Organic Compounds (VOCs) emitted from semiconductor workplace such as photolithography (PHOTO), flat panel display (FPD), organic light emitting diode (OLED), etching (WET) process. The averaged VOCs mixing ratio in the such workplace, PHOTO was 6.5 ppm, FPH was 6.4 ppm, WET was 2.0 ppm and OLED was 1.3 ppm, respectively. The abundance of VOCs in the workplace were methyl ethyl ketone (MEK) with 2.8 ppm (69%) and acetaldehyde with 0.5 ppm (13.2%). Depending on the semiconductor process characteristics, various VOCs have been observed in the workplace. The VOCs mixing ratio are lower than the workplace regulation standard (TWA), it is necessary to continuously monitor and effectively manage these VOCs.

• Toxicological Research
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• v.21 no.4
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• pp.291-295
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• 2005

To define the effect of silica on the stimulator of signaling pathway, we studied the phospholipase D (PLD) activity in the Rat2 fibroblasts. Silica stimulated the accumulation of labeled $[^3H]$ phosphatidylethanol$([^3H]\;PEt)$ in a time- and concentration-dependent manner. This Silicainduced PLD activity was partially attenuated by the pretreatment with U73122 (phospholipase C inhibitor), genistein (protein tyrosine kinase inhibitor), PD 98056 (MEK inhibitor) and mepacrine (phospholipase $A_2$ inhibitor). But, sphingosine (protein kinase C inhibitor) and DPI (NADPH reductase inhibitor) had not effect the PLD activity. Silica also increased the PLD activity about four fold, which imply that the PLD activity is more influenced by the mobilization of PLD than other signaling mediators. The PLD activity also partially inhibited calcium chelator EGTA or/and BAPTA/AM compared to silica. Finally, we concluded that a silica-stimulated phospholipase D activity is present in the Rat2 fibroblasts and is modulated by combination of various signaling mediators.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.183-187
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• 1997

This study was carried out to find the growth characteristics and content of sarsasapogenin in different plant parts of Anemarrhena asphodeloides Bunge. Five native-cultivars were collected and evaluated for several agronomic traits. The collected native-cultivars were classified into two seed-attached peduncle and vegetative propagation types. Seed-attached peduncle lines were predominance of growth traits than vegetative propagation. For the content of sarsasapogenin in each part was investigated, BuOH extarct of 'timo' was developed on silica gel 60G plate using elution solvent($CHC1_2$: Methyl ethyl Ketone : EtOH = 11 : 2 : 0.5). The developed plate were examined using Dual Wavelength Zig - Zag using. Content of sarsasapogenin in main root and lateral root were respectively 1.67mg/g and 1.31mg/g.

• Archives of Pharmacal Research
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• v.27 no.3
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• pp.324-333
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• 2004

To determine whether Insulin-like growth factor (IGF-I) treatment represents a potential means of enhancing the survival of cardiac muscle cells from adriamycin (ADR)-induced cell death, the present study examined the ability of IGF-I to prevent cell death. The study was performed utilising the embryonic, rat, cardiac muscle cell line, H9C2. Incubating cardiac muscle cells in the presence of adriamycin increased cell death, as determined by MTT assay and annexin V-positive cell number. The addition of 100 ng/mL IGF-I, in the presence of adriamycin, decreased apoptosis. The effect of IGF-I on phosphorylation of PI, a substrate of phosphatidylinositol 3-kinase (PI 3-kinase) or protein kinase B (AKT), was also examined in H9C2 cardiac muscle cells. IGF-I increased the phosphorylation of ERK 1 and 2 and $PKC{\;}{\zeta}{\;}kinase$. The use of inhibitors of PI 3-kinase (LY 294002), in the cell death assay, demonstrated partial abrogation of the protective effect of IGF-I. The MEK1 inhibitor-PD098059 and the PKC inhibitor-chelerythrine exhibited no effect on IGF-1-induced cell protection. In the regulatory subunit of PI3K-p85- dominant, negative plasmid-transfected cells, the IGF-1-induced protective effect was reversed. This data demonstrates that IGF-I protects cardiac muscle cells from ADR-induced cell death. Although IGF-I activates several signaling pathways that contribute to its protective effect in other cell types, only activation of PI 3-kinase contributes to this effect in H9C2 cardiac muscle cells.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.1 s.53
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• pp.51-58
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• 2005

The objective of this study was to evaluate the effect of cigarette filter on in vitro cytotoxicity of cigarette mainstream smoke from the cigarette. In this work, we used 3 types of cigarettes included non-filtered 2R4F cigarette, cellulose acetate-filtered 2R4F cigarette, and carbon dual-filtered 2R4F cigarette which was made from original 2R4F by replacing with an acetate filter containing carbon. The cytotoxicity of both the cigarette smoke condensate (CSC), which was collected in Cambridge filter pad, and the gas/vapor phase (GVP), which was bubbled through in phosphate-buffered saline in a gas-washing bottle, was determined using a neutral red uptake assay with CHO-K1 cells. With regard to cytotoxicity when calculated on an equal puff basis, the cytotoxicity of CSC from the filtered cigarettes was lower than that of the non filtered cigarette. Also, $EC_{50}$ vlaue of GVP from carbon filter cigarette was 40.9 puff/L, indicating the cytotoxicity to be $20\%$ lower than that of the CA filter cigarette. The cytotoxicity of the GVP was correlated to the several vapor phase components (formaldehyde, acetaldehyde, acetone, acrolein, crotonaldehyde and MEK). In conclusion, carbon filter, which significantly reduced the amount of carbonyl compounds in mainstream cigarette smoke, results in significant reductions in the cytotoxicity potential of the smoke.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.5
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• pp.492-503
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• 2014

In this study, emission characteristics of volatile odorant species released from urine samples were investigated in relation to two key variables: [1] storage conditions before sampling and [2] incubation conditions during sampling. To this end, 20 offensive odorants were quantified by four different analytical systems and then sorted according to seven functional groups. It is indicated that benzene (B), styrene (S), isobutyl alcohol (i-BuAl), butyl acetate (BuAc), butyraldehyde (BA), isovaleraldehyde (IA), and valeraldehyde (VA) did not contribute to urine odor because their concentration levels were measured below detection limits in all samples. On the other hand, emission concentrations of toluene (T), methyl ethyl ketone (MEK), methyl mercaptan ($CH_3SH$), carbon disulfide ($CS_2$), and ammonia ($NH_3$) were generally higher than other compounds. In terms of odor intensity (OI), $CH_3SH$ and $NH_3$ showed the largest OI values in the range of 2~4. According to t-test (storage approach and urine temperature), the results of T, $CS_2$, and $NH_3$ were statistically distinguished from each other in terms of differences in sampling temperature. Likewise, the emissions of certain odorants from urine samples were affected by changes in sample treatment conditions to a degree.