• Journal of the Economic Geographical Society of Korea
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• v.6 no.1
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• pp.45-60
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• 2003

As the process of economic globalization deepens market uncertainty and severe competition, modern companies are tend to rely on non-market, socio-economic mechanisms such as trust, collaboration, and interdependence, They are being more influenced by cultural economic mechanisms like networks, embeddedness, and placeness rather than explicit cost-reductions. This paper analyzes the characteristics of industrial clusters, the formation of social capital, and the process of institutionalization by comparing two distinctive types of clusters, say Teheran and East-Gate Valleys in Seoul, Korea. The one is mainly consisted of IT industries with increasing vertical integration supported by venture capitals and favorable business infrastructures. The other cluster has long been a traditional CBD frame of Seoul and has transformed to the most dynamic and productive area, characterized by one-stop 'R&D-production-distribution-consumption-after sales services'. The study of the developmental trajectory and key characteristics for these kinds of clusters can give us insight for the cluster theory. This paper firstly reviews the similarities and differences between the social capital in general and that of industrial clusters. It then profiles the growth of the two clusters over the past decade, and compares the current spatial and business structure of the two clusters, focusing on transactions costs, the creation and flow of information, and the local institutions. The paper concludes with some comments about the prospects and perils of the two types industrial clusters of Seoul.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1325-1331
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• 2012

Tumor formation and growth is dictated by a very small number of tumor cells, called cancer stem cells, which are capable of self-renewal. The genesis of cancer stem cells and their resistance to conventional chemotherapy and radiotherapy via mechanisms such as multidrug resistance, quiescence, enhanced DNA repair abilities and anti-apoptotic mechanisms, make it imperative to develop methods to identify and use these cells as diagnostic or therapeutic targets. Aldehyde dehydrogenase 1 (ALDH1) is used as a cancer stem cell marker. In this study, we evaluated ALDH1 expression in CaSki, HeLa and SiHa cervical cancer cells using the Aldefluor method to isolate ALDH1-positive cells. We showed that higher ALDH1 expression correlated with significantly higher rates of cell proliferation, microsphere formation and migration. We also could demonstrate that SiHa-ALDH1-positive cells were significantly more tumorigenic compared to SiHa-ALDH1-negative cells. Similarly, SiHa cells overexpressing ALDH1 were significantly more tumorigenic and showed higher rates of cell proliferation and migration compared to SiHa cells where ALDH1 expression was knocked down using a lentivirus vector. Our data suggested that ALDH1 is a marker of cervical cancer stem cells and expand our understanding of its functional role.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.1
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• pp.71-77
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• 2011

Gastric ulcer has multifactorial etiology, and the development of ulcer is known to be caused by gastric acidity, pepsin secretion, gastric motility and gastric mucosal blood flow. The ulcer results from the tissue necrosis and apoptotic cell death triggered by mucosal ischemia, free radical formation and cessation of nutrient delivery. The gastric mucosa is usually exposed to a wide range of aggressive insults, and has developed efficient mechanisms to repair tissue injury. The apoptotic process of gastric mucosa is triggered by the induction of such proapoptotic gene expression, such as BAX. The Bcl-2 family of proteins plays a pivotal role in the regulation of apoptosis. The maintenance of gastric mucosa integrity depends upon the ratio between cell proliferation and cell death. Stress-inducing factors may affect Bcl-2/BAX ratio and thus the rate of apoptosis through modulation of the expression of both proteins depends upon the experimental model. In addition to the regulation of apoptosis, new vessels have to be generated in order to ensure an adequate supply of oxygen and nutrients to the healing gastric mucosa. This events are regulated by several factors. Among them, such polypeptide growth factors, such as vascular endothelial growth factor (VEGF) regulates essential cell functions involved in tissue healing including cell proliferation and differentiation. The purpose of this study was carried to investigate whether Rhei Rhizoma administration might protect apoptotic cell death and promote angiogenesis in gastric mucosa. Sprague-Dawley rats were randomly divided into 4 groups; normal, saline, cimetidine and Rhei Rhizoma-treated group. The saline, cimetidine and Rhei Rhizoma extracts were orally administrated to each group and gastric ulcer was induced by HCl-EtOH solution. After 1 hour, the stomachs were collected for histological observation and immunohistochemistry. In results, Rhei Rhizoma proves to promote to heal wound in gastric ulcer in conclusion and the significant changes of BAX, Bcl-2 and VEGF quantity in gastric mucosa were observed. These results suggest that Rhei Rhizoma extract may promote incision wound healing and has protective effects on gastric ulcer in rats.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3233-3238
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• 2012

Esophageal carcinoma (EC) is one of the most aggressive cancers with a poor prognosis. Understanding the molecular mechanisms underlying esophageal cancer progression is a high priority for improved EC diagnosis and prognosis. Recently, MSP58 was shown to behave as an oncogene in colorectal carcinomas and gliomas. However, little is known about its function in esophageal carcinomas. We therefore examined the effects of MSP58 knockdown on the growth of esophageal squamous cell carcinoma (ESCC) cells in vitro and in vivo in order to gain a better understanding of its potential as a tumor therapeutic target. We employed lentiviral-mediated small hairpin RNA (shRNA) to knock down the expression of MSP58 in the ESCC cell lines Eca-109 and EC9706 and demonstrated inhibition of ESCC cell proliferation and colony formation in vitro. Furthermore, flow cytometry and western blot analyses revealed that MSP58 depletion induced cell cycle arrest by regulating the expression of P21, CDK4 and cyclin D1. Notably, the downregulation of MSP58 significantly inhibited the growth of ESCC xenografts in nude mice. Our results suggest that MSP58 may play an important role in ESCC progression.

• Journal of Ginseng Research
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• v.40 no.2
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• pp.151-159
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• 2016

Background: Ginsenoside-Rg3, the pharmacologically active component of red ginseng, has been found to inhibit tumor growth, invasion, metastasis, and angiogenesis in various cancer models. Previously, we found that 20(R)-ginsenoside-Rg3 (Rg3) could inhibit angiogenesis. Since microRNAs (miRNAs) have been shown to affect many biological processes, they might play an important role in ginsenoside-mediated angiomodulation. Methods: In this study, we examined the underlying mechanisms of Rg3-induced angiosuppression through modulating the miRNA expression. In the miRNA-expression profiling analysis, six miRNAs and three miRNAs were found to be up- or down-regulated in vascular-endothelial-growth-factor-induced human-umbilical-vein endothelial cells (HUVECs) after Rg3 treatment, respectively. Results: A computational prediction suggested that mature hsa-miR-520h (miR-520h) targets ephrin receptor (Eph) B2 and EphB4, and hence, affecting angiogenesis. The up-regulation of miR-520h after Rg3 treatment was validated by quantitative real-time polymerase chain reaction, while the protein expressions of EphB2 and EphB4 were found to decrease, respectively. The mimics and inhibitors of miR- 520h were transfected into HUVECs and injected into zebra-fish embryos. The results showed that overexpression of miR-520h could significantly suppress the EphB2 and EphB4 protein expression, proliferation, and tubulogenesis of HUVECs, and the subintestinal-vessel formation of the zebra fish. Conclusion: These results might provide further information on the mechanism of Rg3-induced angiosuppression and the involvement of miRNAs in angiogenesis.

• The Journal of Internal Korean Medicine
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• v.32 no.4
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• pp.565-583
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• 2011

Objectives : This study investigated the biochemical mechanisms of anti-proliferative and pro-apoptotic effects of the water extract of Dan-Seon-Tang (DST) in human leukemia U937 cells. Methods : U937 cells were exposed to DST and growth inhibition was measured by MTT assay. Results : Exposure of U937 cells to DST resulted in the growth inhibition in a concentration-dependent manner. This inhibitory effect was associated with morphological changes and apoptotic cell death such as formation of apoptotic bodies, increased populations of apoptotic-sub G1 phase and induction of DNA fragmentation. The induction of apoptotic cell death in U937 cells by DST was associated with up-regulation of death receptor 4 (DR4) and down-regulation of Bid, surviving and cellular inhibition of apoptosis protein-2 (cIAP-2) expression. DST treatment also induced the proteolytic activation of caspase-3, caspase-8 and caspase-9, and a concomitant degradation of caspase-3 substrate proteins such as poly (ADP-ribose) polymerase (PARP), phospholipase (PLC)-${\gamma}1$, ${\beta}$-catenin and DNA fragmentation factor 45/inhibotor of caspase activated DNAse (DFF45/ICAD). Furthermore, apoptotic cell death by DST was significantly inhibited by caspase-3 specific inhibitor z-DEVD-fmk, demonstrating the important role of caspase-3. Conclusions : These findings suggest that herb prescription DST may be a potential chemotherapeutic agent for the control of human leukemia U937 cells; further study is needed to identify the active compounds.

• BMB Reports
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• v.53 no.12
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• pp.634-639
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• 2020

In prostate cancer, the androgen receptor (AR) transcription factor is a major regulator of cell proliferation and metastasis. To identify new AR regulators, we focused on Mixed lineage leukemia 5 (MLL5), a histone-regulating enzyme, because significantly higher MLL5 expression was detected in prostate cancer tissues than in matching normal tissues. When we expressed shRNAs targeting MLL5 gene in prostate cancer cell line, the growth rate and AR activity were reduced compared to those in control cells, and migration ability of the knockdown cells was reduced significantly. To determine the molecular mechanisms of MLL5 on AR activity, we proved that AR physically interacted with MLL5 and other co-factors, including SET-1 and HCF-1, using an immunoprecipitation method. The chromatin immunoprecipitation analysis showed reduced binding of MLL5, co-factors, and AR enzymes to AR target gene promoters in MLL5 shRNA-expressing cells. Histone H3K4 methylation on the AR target gene promoters was reduced, and H3K9 methylation at the same site was increased in MLL5 knockdown cells. Finally, xenograft tumor formation revealed that reduction of MLL5 in prostate cancer cells retarded tumor growth. Our results thus demonstrate the important role of MLL5 as a new epigenetic regulator of AR in prostate cancer.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.1
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• pp.159-165
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• 2013

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor (TGF-${\beta}$) superfamily and are involved in osteoblastic differentiation. The largest TGF-${\beta}$ superfamily subgroup shares genetic homology with human BMPs (hBMPs) and silkworm decapentaplegic (dpp). In addition, hBMPs are functionally interchangeable with Drosophila dpp. Bombyx mori dpp may induce bone formation in mammalian cells. To test this hypothesis, we synthesized the 1,285-base pairs cDNA of full-length B. mori dpp using total RNAs obtained from the fat body of 3-day-old of the $5^{th}$ instar larvae and cloned the cDNA into the pCEP4 mammalian expression vector. Next, B. mori dpp was expressed in C3H10T1/2 cells. The target cells transfected with the pCEP4-Bm dpp plasmid showed biological functions similar to those of osteogenic differentiation induction growth factors such as hBMPs. We determined the relative mRNA expression rates of Runt-related transcription factor 2 (RUNX2), osterix, osteocalcin, and alkaline phosphatase (ALP) to validate the osteoblast-specific differentiation effects of B. mori dpp by performing quantitative real-time RT-PCR. Interestingly, mRNA expression levels of the 3 marker genes except RUNX2, in cells expressing B. mori dpp were much higher than those in control cells and C3H10T1/2 cells transfected with pCEP4. These results suggested that B. mori dpp signaling regulates osterix expression during osteogenic differentiation via RUNX2-independent mechanisms.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.15-15
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• 2014

Fusarium graminearum (teleomorph Gibberella zeae) is an important plant pathogen that causes head blight of major cereal crops such as wheat, barley, and rice, as well as causing ear and stalk rot on maize worldwide. Plant diseases caused by this fungus lead to severe yield losses and accumulation of harmful mycotoxins in infected cereals [1]. Fungi utilize spore production as a mean to rapidly avoid unfavorable environmental conditions and to amplify their population. Spores are produced sexually and asexually and their production is precisely controlled. Upstream developmental activators consist of fluffy genes have been known to orchestrate early induction of condiogenesis in a model filamentous fungus Aspergillus nidulans. To understand the molecular mechanisms underlying conidiogenesis in F. graminearum, we characterized functions of the F. graminearum fluffy gene homologs [2]. We found that FlbD is conserved regulatory function for conidiogenesis in both A. nidulans and F. graminearum among five fluffy gene homologs. flbD deletion abolished conidia and perithecia production, suggesting that FlbD have global roles in hyphal differentiation processes in F. graminearum. We further identified and functionally characterized the ortholog of AbaA, which is involved in differentiation from vegetative hyphae to conidia and known to be absent in F. graminearum [3]. Deletion of abaA did not affect vegetative growth, sexual development, or virulence, but conidium production was completely abolished and thin hyphae grew from abnormally shaped phialides in abaA deletion mutants. Overexpression of abaA resulted in pleiotropic defects such as impaired sexual and asexual development, retarded conidium germination, and reduced trichothecene production. AbaA localized to the nuclei of phialides and terminal cells of mature conidia. Successful interspecies complementation using A. nidulans AbaA and the conserved AbaA-WetA pathway demonstrated that the molecular mechanisms responsible for AbaA activity are conserved in F. graminearum as they are in A. nidulans. F. graminearum ortholog of Aspergillus nidulans wetA has been shown to be involved in conidiogenesis and conidium maturation [4]. Deletion of F. graminearum wetA did not alter mycelial growth, sexual development, or virulence, but the wetA deletion mutants produced longer conidia with fewer septa, and the conidia were sensitive to acute stresses, such as oxidative stress and heat stress. Furthermore, the survival rate of aged conidia from the F. graminearum wetA deletion mutants was reduced. The wetA deletion resulted in vigorous generation of single-celled conidia through autophagy-dependent microcycle conidiation, indicating that WetA functions to maintain conidia dormancy by suppressing microcycle conidiation in F. graminearum. In A. nidulans, FlbB physically interacts with FlbD and FlbE, and the resulting FlbB/FlbE and FlbB/FlbD complexes induce the expression of flbD and brlA, respectively. BrlA is an activator of the AbaA-WetA pathway. AbaA and WetA are required for phialide formation and conidia maturation, respectively [5]. In F. graminearum, the AbaA-WetA pathway is similar to that of A. nidulans, except a brlA ortholog does not exist. Amongst the fluffy genes, only fgflbD has a conserved role for regulation of the AbaA-WetA pathway.

• Journal of Chest Surgery
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• v.39 no.11 s.268
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• pp.805-809
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• 2006

Background: In our previous study, we demonstrated that transforming growth factor-beta 1 receptor II(TGF-${\beta}1RII$) may have a role in the formation of bullae. In this study, we investigated if expression of transforming growth factor-beta 1 (TGF-${\beta}1$) ligand was altered in a bullous lung tissue by immunohistochemical staining of bullous tissues from patients with primary spontaneous pneumothorax. Material and Method: Bullous lung tissues were obtained from 36 patients with primary spontaneous pneumothorax, including 34 males and 2 females aged 14 to 38 years old. Result: Of the 36 patients, 19 were TGF-${\beta}1$ positive and 24 were transforming growth factor-beta 1 receptor II(TGF-${\beta}1RII$) positive. Among the 19 TGF-${\beta}1$ positives, 15 were also TGF-${\beta}1RII$ positive, observation at high magnification showed that strong immunohistochemical stain was detected in the boundary region between the bullous and normal lung tissues. Conclusion: These results suggest that overexpression of TGF-${\beta}1$ may be involved in the formation of a bulla as well as the alteration of TGF-${\beta}1RII$ expression. Further molecular studies are needed to elucidate the more detailed molecular mechanisms of the bulla formation.