• BMB Reports
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• v.37 no.4
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• pp.454-459
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• 2004

Experimental hyperoxia represents a suitable in vitro model to study some pathogenic mechanisms related to oxidative stress. Moreover, it allows the investigation of the molecular pathophysiology underlying oxygen therapy and toxicity. In this study, a modified experimental set up was adopted to accomplish a model of moderate hyperoxia (50% $O_2$, 96 h culture) to induce oxidative stress in the human leukemia cell line, U-937. Spectrophotometric measurements of mitochondrial respiratory enzyme activities, NMR spectroscopy of culture media, determination of antioxidant enzyme activities, and cell proliferation and differentiation assays were performed. The data showed that moderate hyperoxia in this myeloid cell line causes: i) intriguing alterations in the mitochondrial activities at the levels of succinate dehydrogenase and succinate-cytochrome c reductase; ii) induction of metabolic compensatory adaptations, with significant shift to glycolysis; iii) induction of different antioxidant enzyme activities; iv) significant cell growth inhibition and v) no significant apoptosis. This work will permit better characterization the mitochondrial damage induced by hyperoxia. In particular, the data showed a large increase in the succinate cytochrome c reductase activity, which could be a fundamental pathogenic mechanism at the basis of oxygen toxicity.

• Journal of Life Science
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• v.34 no.6
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• pp.418-425
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• 2024

Solid tumors are heterogeneous populations of multiple cell types. While the majority of the cells that comprise cancer are unable to divide, cancer stem cells have self-renewal and differentiation properties. Normal stem cell pathways that control self-renewal are overactivated in cancer stem cells, making cancer stem cells important for cancer cell expansion and progression. Dick first proposed the definition of cancer stem cells in acute myeloid leukemia, according to which cancer stem cells can be classified based on the expression of cell surface markers. Cancer stem cells maintain their potential in the tumor microenvironment. Multiple cell types in the tumor microenvironment maintain quiescent cancer stem cells and serve as regulators of cancer growth. Since current cancer treatments target proliferative cells, quiescent state cancer stem cells that are resistant to treatment increase the risk of recurrence or metastasis. Various signals of the tumor microenvironment induce changes to become a tumor-supportive environment by remodeling the vasculature and extracellular matrix. To effectively treat cancer, cancer stem cells and the tumor microenvironment must be targeted. Therefore, it is important to understand how the tumor microenvironment induces reprogramming of the immune response to promote cancer growth, immune resistance, and metastasis. In this review, we discuss the cellular and molecular mechanisms that can enhance immunosuppression in the tumor microenvironment.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3437-3441
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• 2012

Background: Oncogenic Bmi-1 (B-lymphoma Moloney murine leukemia virus insertion region-1) belongs to the Polycomb-group (PcG) family of proteins and plays an important role in the regulation of proliferation, senescence, cell cycle and apoptosis, chromosome stability, activation of gene transcription. Methods: To clarify the roles of Bmi-1 in tumourigenesis and progression of gastric carcinomas, it was examined by immunohistochemistry (IHC) and real-time RT-PCR in gastric carcinomas, dysplasia, intestinal metaplasia (IM), and gastritis with a comparison of its expression with clinicopathological parameters of carcinomas. Results: There was gradually increased Bmi-1 protein expression from gastritis, IM, dyplasia to carcinoma (p<0.001). Bmi-1 expression was positively linked to tumor size, depth of invasion, lymph node metastasis and worse prognosis of carcinomas (p<0.001), but not to age or sex of carcinoma patients (p>0.05). There was higher Bmi-1 protein expression in intestinal-type carcinomas than diffuse-type ones (p<0.001). At mRNA level, Bmi-1 protein expression was increased from gastritis, IM, dysplasia and carcinoma (p<0.001). Bmi-1 overexpression was observed in gastric carcinoma with larger diameter, deeper invasion, lymph node metastasis, and intestinal-type carcinoma (p<0.05). Conclusion: These findings indicate that up-regulated Bmi-1 expression is positively linked to pathogenesis, growth, invasion, metastasis and differentiation of gastric carcinomas. It was considered as a promising marker to indicate the aggressive behaviors and prognosis of gastric carcinomas.

• Biomolecules & Therapeutics
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• v.29 no.1
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• pp.73-82
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• 2021

Hsp90 is often overexpressed with activated form in cancer cells, and many key cellular proteins are dependent upon the Hsp90 machinery (these proteins are called "client protein"). Nowadays, more client proteins and more inhibitors of Hsp90 are being discovered. Chaetocin has been identified as an inhibitor of histone methyl transferase SUV39H1. Herein, we find that Chaetocin is an inhibitor of Hsp90 which binds to the C-terminal of Hsp90α. Chaetocin inhibited a variety of Hsp90 client proteins including AMl1-ETO and BCL-ABL, the mutant fusion-protein in the K562 and HL-60 cells. SUV39H1 mediates epigenetic events in the pathophysiology of hematopoietic disorders. We found that inhibition of Hsp90 by Chaetocin and 17-AAG had ability to induce degradation of SUV39H1 through proteasome pathway. In addition, SUV39H1 interacted with Hsp90 through co-chaperone HOP. These results suggest that SUV39H1 belongs to a client protein of Hsp90. Moreover, Chaetocin was able to induce cell differentiation in the two cells in the concentration range of Hsp90 inhibition. Altogether, our results demonstrate that SUV39H1 is a new client protein of Hsp90 degradated by Chaetocin as a novel C-terminal inhibitor of Hsp90. The study establishes a new relationship of Chaetocin and SUV39H1, and paves an avenue for exploring a new strategy to target SUV39H1 by inhibition of Hsp90 in leukemia.

• Development and Reproduction
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• v.12 no.1
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• pp.77-86
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• 2008

This study was carried out to investigate the effect of leukemia inhibitory factor (LIF) on the derivation of mouse ES cells from isolated blastomeres. Two-cell stage mouse embryos were obtained from superovulated BDF1 female mice. Collected embryos were cultured to blastocyst stage in culture medium supplemented with 0, 1,000, 2,500 or 5,000 U/mL of LIF. Cultured blastocysts were examined by counting the number of cells in the inner cell mass (ICM) and trophectoderm (TE) using differential staining method. When 2-cell embryos were cultured with 2,500 U/ml of LIF, the cell numbers of ICM significantly increased in comparing with those of the control($21.0{\pm}4.0$ vs. $15.9{\pm}5.0$, P<0.01) and 1,000 U/mL of LIF-containing group ($21.0{\pm}4.0$ vs. $16.6{\pm}4.9$, P<0.05). We used an ES cell establishment medium with 20% Knockout Serum Replacement and 0.01 mg/mL ACTH instead of fetal bovine serum. Establishing efficacy of ES cell lines were the highest in 2,500 U/mL of LIF-containing group as 36.7% (11/30). This culture medium was applied to the culture of isolated blastomeres and to derivate ES cell lines. Three ES cell lines (21.4%) from isolated blastomeres of 2-cell stage embryos were established. In further experiments, we could establish one ES cell line (4.0%) from single blastomere of 4-cell stage embryo. The subcultured ES cells and their embryoid bodies were characterized by analyzing gene expression for undifferentiation and differentiation marker gene using immunocytochemistry and RT-PCR. In conclusion, LIF supplementation in culture medium could increase the cell number in ICM of blastocysts and support derivation of ES cell lines from isolated blastomeres.

• Korean Journal of Medicinal Crop Science
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• v.12 no.4
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• pp.273-278
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• 2004

The anticancer activities of the extracts from Acanthopanax senticosus Harms, Ephedra sinica Stapf, Rubus coreanus Miq and Artemisia capillaris Thunb were compared according to extract systems. About 70% of the growth of human hepatocarcinoma cancer cell was inhibited in adding 1.0 mg/ml of the water extract from Rubus coreanus Miq with ultrasonification at $60^{\circ}C$. The growth of human normal lung cell was limited to 25% in adding the extracts with ultrasonification at $60^{\circ}C$. The effect of extracts obtained by only water and with ultrasonification on different of human promyelocytic leukemia cells was also observed.

• Journal of Life Science
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• v.30 no.8
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• pp.713-721
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• 2020

Adipogenesis as a model system is needed to understand the molecular mechanisms of human adipocyte biology and the pathogenesis of obesity, diabetes, and other metabolic syndromes. Many relevant studies have been conducted with a focus on gene expression regulation and intracellular signaling relating to Peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), which are master adipogenic transcription factors. However, epigenome regulation of adipogenesis by epigenomic modifiers or histone mutations is not fully understood. Histone methylation is one of the major epigenetic modifications on gene expression in mammals, and histone H3 lysine methylation (H3Kme) in particular implicates cell differentiation during various tissue and organ development. During adipogenesis, cell type-specific enhancers are marked by histone H3K4me1 with the active enhancer mark H3K27ac. Mixed-lineage leukemia 4 (MLL4) is a major H3K4 mono-methyltransferase on the adipogenic enhancers of PPARγ and C/EBPα loci. Thus, MLL4 is an important epigenomic modifier for adipogenesis. The repressive mark H3K27me3 is mediated by the enzymatic subunit Enhancer zeste homolog 2 (EZH2) of the polycomb repressive complex 2. EZH2-mediated H3K27 tri-methylation on the Wnt gene increases adipogenesis because WNT signaling is a negative regulator of adipogenesis. This review summarizes current knowledge about the epigenomic regulation of adipogenesis by histone H3 lysine methylation which fundamentally regulates gene expression.

• Tuberculosis and Respiratory Diseases
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• v.46 no.3
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• pp.327-337
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• 1999

Background: Reactive oxygen species are involved in multi-stage process of carcinogenesis. The moot of cancer cell lines and cancer cells in tumor tissue produce reactive oxygen species and on the other hand, the activities of catalase, Mn- and CuZn-superoxide dismutase in tumor cells are usually low. These persistent oxidative stress in tumor tissue facilitates tumor invasion and metastasis. 12-kDa thioredoxin, which regulates the intracellular redox potential with glutathione and glutaredoxin is involved in cell activation, proliferation, differentiation and redox-mediated apoptosis. It is also purified as 14-kDa and 10-kDa eooinophilic cytotoxic enhancing factor(ECEF) from human histiocytic cell(U937) and 10-kDa ECEF has more than 20 times eosinophilic stimulation activity than 14-kDa ECEF. It has been reported that adult T-cell leukemia, squamous cell carcinoma of uterine cervix, and hepatocellular carcinoma show increased amounts of human thioredoxin and thioredoxin mRNA is increased in lung cancer. In this study, we investigated the expression of conventional antioxidant enzymes such as catalase, CuZn-SOD, and glutathione peroxidase and thioredoxin in lung cancer tissue compared to adjacent normal lung tissue and the induction of thioredoxin in macrophage cells after treatment of oxidative stress and endotoxin Methods: We measured the amount of conventional antioxidant enzymes such as catalase, CuZn-SOD, and glutathione peroxidase and thioredoxin in lung cancer tissue compared to adjacent normal lung tissue by immunoblot analysis and the induction of thioredoxin in mouse monocyte-macrophage cells(RAW 264.7) by treatment of 5 ${\mu}M$ menadione and 1 ${\mu}g/ml$ endotoxin Results: On immunoblot analysis, the expression of 12-kDa thioredoxin was increased in lung cancer tissue compared to paired normal lung tissue. but the expression of catalase and CuZn-SOD were decreased in lung cancer tissue compared to paired normal tissue and the expression of glutathione peroxidase in lung cancer was variable. The expression of truncated thioredoxin was also increased in lung cancer. When mouse monocyte-macrophage cells were treated with 5 ${\mu}M$ menadione and 1 ${\mu}g/ml$ endotoxin, the expression of thioredoxin was peaked at 12 hrs and sustained to 48 hrs. Conclusion: In contrast with other conventional antioxidants, the expression of 12-kDa and truncated thioredoxin in lung cancer were increased and it is closely associated with persistent oxidative stress in tumor microenvironment. Considering especially the biological functions of truncated thioredoxin, the increased amount of truncated thioredoxin has significant role in tumor growth through cell proliferation.

• Journal of Life Science
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• v.32 no.2
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• pp.167-174
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• 2022

In modern society, interest in antioxidants is increasing as the stress caused by oxidants increases. However, the demand for synthetic antioxidants is decreasing because some studies have confirmed that they are harmful when consumed in large quantities; thus, studies on antioxidants derived from natural substances are actively being conducted to replace synthetic antioxidants. Blueberry, known as one of the world's top ten long-lived foods, is a plant of the Vaccinium (Ericaceae) family, and various pharmacological activities of blueberry including antioxidant activity have been studied. Vaccinium oldhamii (VO) is a deciduous broad-leaved shrub in the same genus as blueberries, and in this paper, we summarize the studies on the efficacy analysis of VO extracts and purified products. The content of phenolic compounds in VO fruits was proportional to antioxidant and anti-influenza activity such as the inhibition of NO production, and the total content of polyphenols and anthocyanin was higher than that in blueberries. VO fruit extracts showed anti-inflammatory activity and anti-cancer activity against human acute leukemia; in contrast, VO branch extracts showed anti-inflammatory activity, activity to inhibit osteoclast differentiation and bone resorption due to inflammatory response, and anti-cancer activity against several human cancer cell lines. Compared to blueberries, VO showed higher phenolic compound content, antioxidant activity, and various physiological activities. In addition, VO is considered to have sufficient value as an alternative crop to blueberries, such as it can be grown natively in Korea, with simple mass cultivation and no need to pay royalties for commercialization.