• Biomolecules & Therapeutics
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• 제15권4호
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• pp.240-244
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• 2007

Cigarette smoking causes serious health problems in humans, especially if smoking habits are established during their adolescence. Nicotine is known to mutate DNA and interfere with apoptosis. Apoptosis is considered as a potent defense mechanism against cellular damaging agents. This study aims to investigate the effect of nicotine on the progression of apoptosis induced under ER stress conditions using four different established cell lines: HEK293, 3T3-L1, C2C12, and HepG2. When treated with nicotine, the progression of apoptosis was notably inhibited in the four cell lines according to the assays of caspase-3 activation and DNA fragmentation. In ER-stressed cells, nicotine appears to inhibit the progression of apoptosis in a concentration-dependent manner. When cells were treated with nicotine prior to ER stress, GRP94 level significantly increased compared to other ER stress markers of PDI and GRP78. This observation suggests that the inhibitory effect of nicotine may results from up-regulation of GRP94, an anti-apoptotic chaperone, under nicotine treatment. Taken together, the present study strongly implies that nicotine may inhibit apoptosis, caused by prolonged ER stress, based on promotion of GRP94 expression.

• 한국양식학회지
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• 제20권4호
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• pp.205-211
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• 2007

Stress-inducible proteins may function in part as molecular chaperones, protecting cells from damage due to various stresses and helping to maintain homeostasis. We examined the mRNA expression patterns of a 68-kDa heat shock protein (HSP68) and 78-kDa glucose-regulated protein (GRP78) in relation to physiological changes in Pacific oyster Crassostrea gigas under osmotic stress. Expression of HSP68 and GRP78 mRNA in the gill significantly increased until 48 h in a hypersaline environment (HRE) and 72 h in a hyposaline environment (HOE), and then decreased. Osmolality and the concentrations of $Na^+$, $Cl^-$, and $Ca^{2+}$ in the hemolymph of HRE oysters significantly increased until 72 h (the highest value) and then gradually decreased; in HOE oysters, these values significantly decreased until 72 h (the lowest value), and then increased. These results suggest that osmolality and $Na^+$, $Cl^-$, and $Ca^{2+}$ concentrations were stabilized by HSP68 and GRP78, and indicate that these two stress-induced proteins play an important role in regulating the metabolism and protecting the cells of the Pacific oysters exposed to salinity changes.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권5호
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• pp.414-419
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• 2006

When the alginate lyase gene (aly) from Pseudoalteromonas elyakovii was expressed in E. coli, most of the gene product was organized as aggregated insoluble particles known as inclusion bodies. To examine the effects of chaperones on soluble and nonaggregated form of alginate lyase in E. coli, we constructed plasm ids designed to permit the coexpression of aly and the DnaK/DnaJ/GrpE or GroEL/ES chaperones. The results indicate that coexpression of aly with the DnaK/DnaJ/GrpE chaperone together had a marked effect on the yield alginate lyase as a soluble and active form of the enzyme. It is speculated this result occurs through facilitation of the correct folding of the protein. The optimal concentration of L-arabinose required for the induction of the DnaK/DnaJ/GrpE chaperone was found to be 0.05mg/mL. An analysis of the protein bands on SDS-PAGE gel indicated that at least 37% of total alginate lyase was produced in the soluble fraction when the DnaK/DnaJ/GrpE chaperone was coexpressed.

• 한국공간구조학회논문집
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• 제11권4호
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• pp.101-108
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• 2011

유리강회플라스틱(GRP)은 재료의 자중에 비해 아주 높은 강도를 가지고 있다. 또한 부재의 두께에 따라서 투명 혹은 반투명의 효과를 거둘 수 있다. 하지만 Hand laminating의 특성상 일률적인 재료의 강도를 선뢰하기 어렵기 때문에 구조 계산 혹은 설계 시 반드시 재료 실험을 수행하여야한다. 본 논문은 두께 4mm, 높이 30m의 의장적 기둥을 구조적으로 설계하기 위한 재료 실험을 수행하였다. 또한 실험 결과에 대한 평가를 통해 DIN에서 규정하는 재료적인 강도와 비교 분석하였다. 이를 통해 규준에서 제시하는 값과의 차이를 확인했으며 실제 설계에 반영하기 위해 반드시 재료실험이 수행되어야함을 알 수 있다.

• 한국인터넷방송통신학회논문지
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• 제9권4호
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• pp.87-97
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• 2009

A Mobile Ad hoc Network (MANET) is characterized by multi-hop wireless connectivity, frequently changing network topology with mobile nodes and the efficiency of the dynamic routing protocol plays an important role in the performance of the network. In this paper, the performance of five routing protocols for MANET is compared by using OPNET modeler: AODV, DSR, GRP, OLSR and TORA. The various performance metrics are examined, such as packet delivery ratio, end-to-end delay and routing overhead with varying data traffic, number of nodes and mobility. In our simulation results, OLSR shows the best performance in terms of data delivery ratio in static networks, while AODV has the best performance in mobile networks with moderate data traffic. When comparing proactive protocols (OLSR, GRP) and reactive protocols (AODV, DSR) with varying data traffic in the static networks, proactive protocols consistently presents almost constant overhead while the reactive protocols show a sharp increase to some extent. When comparing each of proactive protocols in static and mobile networks, OLSR is better than GRP in the delivery ratio while overhead is more. As for reactive protocols, DSR outperforms AODV under the moderate data traffic in static networks because it exploits caching aggressively and maintains multiple routes per destination. However, this advantage turns into disadvantage in high mobility networks since the chance of the cached routes becoming stale increases.

• Journal of Microbiology and Biotechnology
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• 제29권4호
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• pp.571-576
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• 2019

Microenvironmental stress, which is naturally observed in solid tumors, has been implicated in anticancer drug resistance. This tumor-specific stress causes the degradation of topoisomerase $II{\alpha}$, rendering cells resistant to topoisomerase $II{\alpha}$-targeted anticancer agents. In addition, microenvironmental stress can induce the overexpression of 78kDa glucose regulated protein (GRP78), which can subsequently block the activation of apoptosis induced by treatment with anticancer agents. Therefore, inhibition of topoisomerase $II{\alpha}$ degradation and reduction in GRP78 expression may be effective strategies for inhibiting anticancer drug resistance. In this study, we investigated the active compound arctigenin, which inhibited microenvironmental stress-induced etoposide resistance in HT-29 cells. Arctigenin was also highly toxic to etoposide-resistant HT-29 cells, with an $IC_{50}$ value of $10{\mu}M$ for colony formation. We further showed that arctigenin inhibited the degradation of topoisomerase $II{\alpha}$ and reduced the expression of GRP78. Thus, these results suggest that arctigenin is a novel therapeutic agent that inhibits resistance to etoposide associated with microenvironmental stress conditions.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6557-6562
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• 2013

Objective: Specific promoters could improve efficiency and ensure the safety of gene therapy. The aim of our study was to screen examples for lung cancer. Methods: The firefly luciferase gene was used as a reporter, and promoters based on serum markers of lung cancer were cloned. The activity and specificity of seven promoters, comprising CEACAM5 (carcinoembryonic antigen, CEA), GRP (Gastrin-Releasing Peptide), KRT19 (cytokeratin 19, KRT), SFTPB (surfactant protein B, SP-B), SERPINB3 (Squamous Cell Carcinoma Antigen, SCCA), SELP (Selectin P, Granule Membrane Protein 140kDa, Antigen CD62, GMP) and DKK1 (Dickkopf-1) promoters were compared in lung cancer cells to obtain cancer-specific examples with strong activity. Results: The CEACAM5, DKK1, GRP, SELP, KRT19, SERPINB3 and SFTPB promoters were cloned. Furthermore, we successfully constructed recombinant vector pGL-CEACAM5 (DKK1, GRP, SELP, KRT19, SERPINB3 and SFTPB) contained the target gene. After cells were transfectedwith recombinant plasmids, we found that the order of promoter activity from high to low was SERPINB3, DKK1, SFTPB, KRT19, CEACAM5, SELP and GRP and the order for promoters regarding specificity and high potential were SERPINB3, DKK1, SELP, SFTPB, CEACAM5, KRT19 and GRP. Conclusion: The approach adopted is feasible to screen for new tumour specific promoters with biomarkers. In addition, the screened lung-specific promoters might have potential for use in lung cancer targeted gene therapy research.

• Asian Pacific Journal of Cancer Prevention
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• 제15권2호
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• pp.605-610
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• 2014

Chronic liver diseases, including cancer, are characterized by inflammation and elevated serum ferritin (SF). However, the causal-relationship remains unclear. This study used primary rat hepatic stellate cells (HSC) as a model to investigate effects of physiological SF concentrations (10, 100 and 1000 pM) because HSCs play a central role in the development and progression of liver fibrosis. Physiological concentrations of SF, either horse SF or human serum, induced pro-inflammatory cytokine $IL1{\beta}$, IL6 and $TNF{\alpha}$ secretion in rat activated HSCs (all p<0.05). By contrast, treatment did not alter activation marker ${\alpha}SMA$ expression. The presence of SF markedly enhanced expression of Grp78 mRNA (p<0.01). Furthermore, transient knock down of Grp78 by endotoxin EGF-SubA abolished SF-induced $IL1{\beta}$ and $TNF{\alpha}$ secretion in activated HSCs (all p<0.05). In conclusion, our results showed that at physiological concentrations SF functions as a pro-inflammatory mediator in primary rat HSCs. We also provide a molecular basis for the action of SF and identified Grp78-associated ER stress pathways as a novel potential therapeutic target for resolution of fibrosis and possible prevention of liver cancer.

• Biomolecules & Therapeutics
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• 제26권5호
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• pp.464-473
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• 2018

Cripto is a small glycosylphosphatidylinositol-anchored signaling protein that can detach from the anchored membrane and stimulate proliferation, migration, differentiation, vascularization, and angiogenesis. In the present study, we demonstrated that Cripto positively affected proliferation and survival of mesenchymal stem cells (MSCs) without affecting multipotency. Cripto also increased expression of phosphorylated janus kinase 2 (p-JAK2), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), 78 kDa glucose-regulated protein (GRP78), c-Myc, and cyclin D1. Notably, treatment with an anti-GRP78 antibody blocked these effects. In addition, pretreatment with STAT3 short interfering RNA (siRNA) inhibited the increase in p-JAK2, c-Myc, cyclin D1, and BCL3 levels caused by Cripto and attenuated the pro-survival action of Cripto on MSCs. We also found that incubation with Cripto protected MSCs from apoptosis caused by hypoxia or $H_2O_2$ exposure, and the level of caspase-3 decreased by the Cripto-induced expression of B-cell lymphoma 3-encoded protein (BCL3). These effects were sensitive to down-regulation of BCL3 expression by BCL3 siRNA. Finally, we showed that Cripto enhanced expression levels of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and hepatocyte growth factor (HGF). In summary, our results demonstrated that Cripto activated a novel biochemical cascade that potentiated MSC proliferation and survival. This cascade relied on phosphorylation of JAK2 and STAT3 and was regulated by GRP78. Our findings may facilitate clinical applications of MSCs, as these cells may benefit from positive effects of Cripto on their survival and biological properties.

• 한국동물학회지
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• 제39권1호
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• pp.47-53
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• 1996

K562 백혈구암 세포의 phorbol 12-myristate 13-acetate(PMA)에 의한 대핵세포로의 분화과정에서 heat shock proteins(HSPs)와 glucose-regulated proteins(GRPs)의 발현을 조사하였다. PMA에 의한 K562 세포의 분화 특징은 세포성장의 억제, 형태학적 변화, gpllIa의 발현 증가, c-myc 발현의 감소 등으로 나타난다. PMA에 의한 대핵세포 분화과정에서, HSP90A, HSP90B 그리고 HSP28 mRNA와 단백질 합성은 현저히 감소하는 반면, GRP78/BiP와 GRP94의 mRNA 합성은 증가하였다. 한편 HSP7OA와 HSP7OB의 mRNA 합성은 감소하였지만, HSP70 단백질의 합성은 변함이 없었다. 이러한 결과는 HSPs와 GRPs가 K562 세포의 증식 또는 대핵세포 분화 과정에서 특이한 역할을 할 것임을 시사하고 있다.