• IMMUNE NETWORK
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• v.2 no.2
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• pp.79-85
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• 2002

Background: In contrast to evidences of Ig H chain receptor editing in transformed cell lines and transgenic mouse models, there has been no direct evidence that this phenomenon occurs in human developing B cells. Methods: $V_HDJ_H$ rearrangements were obtained from genomic DNA of individual $IgM^-$ B cells from liver and $IgM^+B$ cells from bone marrow of 18 wk of gestation human fetus by PCR amplification and direct sequencing. Results: We found three examples of H chain receptor editing from $IgM^+$ and $IgM^-human$ fetal B cells. Two types of $V_H$ replacements were identified. The first involved $V_H$ hybrid formation, in which part of a $V_H$ gene from the initial VDJ rearrangement is replaced by part of an upstream $V_H$ gene at the site of cryptic RSS. The second involved a gene conversion like replacement of CDR2, in which another $V_H$ gene donated a portion of its CDR2 sequence to the initial VDJ rearrangement. Conclusion: These data provide evidence of receptor editing at the H chain loci in developing human B cells, and also the first evidence of a gene conversion event in human Ig genes.

• The Korean Journal of Community Living Science
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• v.26 no.1
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• pp.103-113
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• 2015

This study examines the effects of Korean Crataegi fructrus(KCF) and Chinese Crataegi fructrus(CCF) on the antioxidative activity and antiproliferation of human cancer cells(HCT-116 human colon, Hep G2 human liver, and A549 human lung cancer cells). The total polyphenol and flavonoid contents, and antioxidative index of the Crataegi fructrus ethanol extracts were significantly higher in KCF than in CCF. The DPPH radical-scavenging activity of the KCF ethanol extract was 82.26%(1000 ppm), and that of the CCF ethanol extract was 77.64%. Antiproliferation effects of 80% ethanol extracts of KCF and CCF on human cancer cells(HCT-116, Hep G2 and A549) increased in a dose-dependent manner. Inhibitory effects of KFC on HCT-116 and A549 cells were greater than those of CCF. The results suggest that ethanol extracts of Crataegi fructrus have antioxidative and hyperplasia inhibition effects on human cancer cells.

• Korean Journal of Pharmacognosy
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• v.37 no.3
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• pp.130-135
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• 2006

The present study describes the preliminary evaluation of the cytotoxic activity of the extracts from Inula japonica. I. japonica was extracted with methanol, ethanol, acetone, and water, and then cytotoxic activity of these extracts were evaluated. The cytotoxic activity of each extract was assessed by the MTT-dye reduction assay. Both ethanol and acetone extracts from I. japonica showed the cytotoxic activity against the HT-29 human colon cancer cells. Furthermore, the ethanol extract was fractionated with n-hexane, diethyl ether, ethyl acetate, and water according to degree of Polarity, The diethyl ether fraction showed the highest cytotoxic activity against HT-29 cells, but the other fractions showed low cytotokic activity. In addition, diethyl ether layer also showed the cytotoxic activity against various tumor cells, such as human colon carcinoma SW620, human cervix adenocarcinoma HeLa, and human breast adenocarcinoma MCF-7 cells as well as HT-29 cells. These studies support that extracts of I. japonica may be a potential candidate as possible chemotherapeutic agent against human cancer.

• Reproductive and Developmental Biology
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• v.31 no.4
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• pp.267-272
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• 2007

Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo and have the capacity to differentiate into various types of cells in the body. Hence, these cells may potentially be an indefinite source of cells for cell therapy in various degenerative diseases including neuronal disorders. For clinical applications of human ES cells, directed differentiation of these cells would be necessary. The objective of this study is to develop the culture condition for the expansion of neural precursor cells derived from human ES cells. Human ES cells were able to differentiate into neural precursor cells upon a stepwise culture condition. Neural precursor cells were propagated up to 5000-fold in cell numbers over 12-week period of culture and evaluated for their characteristics. Expressions of sox1 and pax6 transcripts were dramatically up-regulated along the differentiation stages by RT-PCR analysis. In contrast, expressions of oct4 and nanog transcripts were completely disappeared in neural precursor cells. Expressions of nestin, pax6 and sox1 were also confirmed in neural precursor cells by immunocytochemical analysis. Upon differentiation, the expanded neural precursor cells differentiated into neurons, astrocytes, and oligodendrocytes. In immunocytochemical analysis, expressions of type III ${\beta}$-tubulin and MAP2ab were observed Presence of astrocytes and oligodendrocytes were also confirmed by expressions of GFAP and O4, respectively. Results of this study demonstrate the feasibility of long-term expansion of human ES cell-derived neural precursor cells in vitro, which can be a potential source of the cells for the treatment of neurodegenerative disorders.

• Toxicological Research
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• v.19 no.1
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• pp.45-50
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• 2003

The purpose of this study was to determine the role of substituted groups in phenolic compounds to develop an anticancer agent having strong cytotoxicity against cancer cells but weak against normal cells. The phenolic compounds used in this study were gallic acid and ferulic acid with hydroxyl and carboxyl groups, syringic acid with hydroxyl, carboxyl and methoxy groups, and pyre-gallol with hydroxyl groups. Cytotoxicities of these compounds were evaluated by MTT assay for cell viability and XTT assay for cell adhesion activity in normal human skin fibroblast (Detroit 551) and human skin melanoma (SK-MEL-3) cells. Syringic acid, gallic acid and ferulic acid decreased the cell viability and cell adhesion activity in SK-MEL-3 cells but not in Detroit 551 cells while pyrogallol decreased in both cells. The susceptibility of cell viability based on the $IC_{50}$ values of MTT assay in Detroit 551 cells was in the following order: pyrogallol > gallic acid > ferulic acid > syringic acid, while it was in SK-MEL-3 cells: Syringic acid > progallol > ferulic acid > gallic acid. These results suggest that carboxyl and methoxy groups of these compounds play an important role in selectivity of cytotoxicity in normal and cancer cells.

• IMMUNE NETWORK
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• v.10 no.6
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• pp.247-249
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• 2010

Foxp3 is a transcript factor for regulatory T cell development. Interestingly, Foxp3-expressing cells were identified in B cells, especially in CD19(+)CD5(+) B cells, while those were not examined in CD19(+)CD5(-) B cells. Foxp3-expressing CD5(+) B cells in this study were identified in human PBMCs and were found to consist of $8.5{\pm}3.5%$ of CD19(+)CD5(+) B cells. CD19(+)CD5(+)Foxp3(+) B cells showed spontaneous apoptosis. Rare CD19(+)CD5(+) Foxp3(+) regulatory B cell (Breg) population was unveiled in human peripheral blood mononuclear cells and suggested as possible regulatory B cells (Breg) as regulatory T cells (Treg). The immunologic and the clinical relevant of Breg needs to be further investigated.

• YAKHAK HOEJI
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• v.54 no.3
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• pp.192-199
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• 2010

Colorectal cancer is one of the most common alimentary malignancies. In this study, the antitumor activity of activated human natural killer (NK) cells against human colorectal cancer was evaluated in vivo. Human NK cells are the key contributors of innate immune response and the effective functions of these cells are enhanced by cytokines. Human peripheral blood mononuclear cells (PBMC) were cultured with interleukin-2 (IL-2)-containing medium for 14 days and resulted in enriched NK cell population. The resulting populations of the cells comprised 7% $CD3^+CD4^+$ cells, 25% $CD3^+CD8^+$ cells, 13% $CD3^-CD8^+$ cells, 4% $CD3^+$CD16/$CD56^+$ cells, 39% $CD3^+$CD16/$CD56^-$ cells, and 52% $CD3^-$CD16/$CD56^+$ cells. Tumor necrosis factor alpha (TNF-$\alpha$), interferon gamma (IFN-$\gamma$), IL-2, IL-4, and IL-5 transcripts of the activated NK cells were confirmed by RT-PCR. In addition, activated NK cells at doses of 2.5, 5 and 10 million cells per mouse inhibited 10%, 34% and 47% of SW620-induced tumor growth in nude mouse xenograft assays, respectively. This study suggests that NK cell-based immunotherapy may be used as an adoptive immunotherapy for colorectal cancer patients.

• Journal of Korean Neurosurgical Society
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• v.30 no.8
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• pp.963-969
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• 2001

Objectives : Cord blood stem cells have been widely used as donor cells for bone marrow transplantation recently. These cells can give rise to a variety of hematopoietic lineages to repopulate the blood. Recent observations reveal that some bone marrow cells and bone marrow stromal cells(MSCs) can grow to become either neurons or glial cells. It is, however, unclear whether or not there exists stems cells which can differentiate into neurons in the blood during the early stages of postnatal life. Methods : Human cord blood stem cells were prepared from human placenta after full term delivery. To induce neuronal differentiation of stem cells, ${\beta}$-mercaptoethanol was treated. To confirm the neuro-glial characteristics of differentiated stem cells, immunocytochemical stain for NeuN, neurofilament, glial fibrillary acidic protein(GFAP), microtubule associated protein2(MAP2) was performed. RT-PCR was performed for detecting nestin mRNA and MAP2 mRNA. Results : We showed in this experiment that neuro-glial markers(NeuN, neurofilament, MAP2, GFAP) were expressed and axon-like cytoplasmic processes are elaborated in the cultured human cord blood stem cells prepared from new born placenta after full term delivery. Nestin mRNA was also detected in fresh cord blood monocytes. Conclusions : These results suggest that human cord blood derived stem cells may be potential sources of neurons in early postnatal life.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.51-54
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• 1998

It has been proved that co-cultivation of human neroblastoma cells and human fibroblast cells can enhance nerve cell growth and the production of BDNF in perfusion cultivation. In batch co-cultivation, maximum cell density was increased up to 1.76${\times}$106 viable cells/mL from 9${\times}$105 viable cells/mL of only neuroblastoma cell culture. The growth of neuroblastoma cells was greatly improved by culturing both nerve and fibroblast cells in a perfusion process, maintaining 1.5${\times}$106 viable cells/mL, which was much higher than that form fed-batch cultivation. The nerve cell growth was greatly enhance in both fed-batch and perfusion cultivations while the growth of fibroblast cells was not. It strongly implies that the factors secreted from human fibrobast cells and/or the environments of co-culture system can enhance both cell growth and BDNF secretion. Specific BDNF production rate was not enhanced in co-cultures; however, the production period was increased as the cell growth was lengthened in the co-culture case. Competitive growth between nerve cells and fibroblast cells was not observed in all cases, showing no changes of fibroblast cell growth and only enhancement of the neuroblastoma cell growth and overall BDNF production. It was also found that the perfusion cultivation was the most appropriate process for cultivating two cell lines simultaneously in a bioreactor.

• Journal of Nutrition and Health
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• v.56 no.1
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• pp.12-23
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• 2023

Purpose: This study investigates the alterations in A549 human non-small-cell lung cancer (NSCLC) cells exposed to Citrus junos extract (CJE). We further examine the antiproliferative and apoptotic effects of CJE on NSCLC cells. Methods: Inhibition of proliferation was examined by applying the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) colorimetric assay on CJE-treated A549 NSCLC cells. The lactate dehydrogenase (LDH) assay was performed to measure the degree of toxicity of CJE on NSCLC cells. The effect on migratory proliferation was confirmed using the scratch wound healing assay. The antiproliferative effect of the CJE on human lung cancer cells was verified through morphological observation, fluorescence microscopy, and caspase-3 colorimetry. Results: Exposure of NSCLC cells to CJE resulted in a dose- and time-dependent decrease in cell activity and increased toxicity to the cells. In addition, microscopic observation revealed a reduced ability of the cancer cells to migrate and proliferate after exposure to the CJE, with simultaneous morphological apoptotic changes. Fluorescence staining and microscopic examination revealed that this death was a process of self-programmed cell death of NSCLC cells. Compared to unexposed NSCLC cells, the expression of caspase-3 was significantly increased in cells exposed to CJE. Conclusion: Exposure of A549 human NSCLC cells to CJE inhibits the proliferation, increases the cytotoxicity, and decreases the ability of cells to migrate and grow. Moreover, the expression of caspase-3 increases after CJE treatment, suggesting that the apoptosis of NSCLC cells is induced by a chain reaction initiated by caspase-3. These results indicate that Citrus junos is a potential therapeutic agent for human non-small-cell lung cancer.