• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.156-156
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• 2001

We have previously shown that H-ras, but N-ras, induces an invasiveness and cell motility in human breast epithelial cells (MCFl0A), while both H-ras and N-ras induce transformed phenotype. It has been recently shown that phosphatidylinositol 3-kinase (PI3K) plays an important role on cell migration. In the present study, we wished to investigate the functional role of PI3K in H-ras-induced invasive phenotype in MCF10A cells.(omitted)

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.142-142
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• 2002

Many studies have identified the phosphatidylinositol 3-kinase (PI3K) as a key regulator for various cellular functions including cell survival, growth and motility. We have previously shown that H-ras, but not N-ras, induces invasiveness and motility in human breast epithelial cells (MCF10A), while both H-ras and N-ras induce transformed phenotype.(omitted)

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.141-141
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• 2003

Ras expression has been suggested as a marker for tumor aggressiveness of breast cancer, including the degrees of invasion and tumor recurrence. We previously showed that p38 MAPK is a key signaling molecule differentially regulated by H-ras and N-ras, leading to H-ras-specific cell invasive and migrative phenotypes in human breast epithelial cells (Cancer Res.: 63, 5454-5461, 2003).(omitted)

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.903-909
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• 2002

Research in the cytokine field has grown exponentially in recent years, and the validity of such studies relies heavily on the appropriate measurement of levels of cytokines in various biological samples. Transforming growth factor (TGF)-$\beta$, a hormonally active polypeptide found in normal and transformed tissue, is a potent regulator of cell growth and differentiation. The most widely used bioassay for TGF-$\beta$ is the inhibition of the proliferation of mink lung epithelial cells. Though detection of [$^3$H]thymidine incorporation is more sensitive than the MTT assay, it presents some disadvantages due to the safety and disposal problems associated with radioisotopes. In this study, we attempted to ascertain the experimental conditions which could be used for measuring the in vitro biological activity of TGF-$\beta$ in a safer and more sensitive way compared with the currently available methods. We compared the commonly used method, the MTT assay, to the XTT assay using different parameters including cell number, incubation time and the wave length used for detecting the product. We examined the anti-proliferative activities of TGF-$\beta$ in three different cell lines: Mv-1-Lu mink lung epithelial cells, MCF10A human breast epithelial cells and H-ras-transformed MCF10A cells. Herein, we present an experimental protocol which provides the most sensitive method of quantifying the biological activity of TGF-$\beta$, with a detection limit of as low as 10 pg/ml: Mv-1-Lu or H-ras MCF10A cells ($1{\times}10^5/well$) were incubated with TGF-$\beta$ at $37^{\circ}C$ in a humidified $CO_2$ incubator for 24 hr followed by XTT treatment and determination of absorbance at 450 or 490 nm. Our results may contribute to the establishment of an in vitro bioassay system, which could be used for the satisfactory quantitation of TGF-$\beta$.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.05a
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• pp.100-101
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• 2003

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2001.10b
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• pp.157-157
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• 2001

• Nutrition Research and Practice
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• v.3 no.2
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• pp.77-83
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• 2009

Retinoic acids (RAs) modulate growth, differentiation, and apoptosis in normal, pre-malignant & malignant cells. In the present study, the effects of RA isomers (all-trans RA, 13-cis RA, and 9-cis RA) on the cell signal transduction of human breast cancer cells have been studied. The relationship between RAs and an enzymatic antioxidant system was also determined. Estrogen-receptor (ER) positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cells were treated with different doses of each RA isomers, all-trans RA, 13-cis RA, or 9-cis RA. Treatment of RA isomers inhibited cell viability and induced apoptosis of MCF-7 cells as a result of increased caspase activity in cytoplasm and cytochrome C released from mitochondria. All-trans RA was the most effective RA isomer in both cell growth inhibition and induction of apoptosis in MCF-7 cells. However, no significant effect of RA isomers was observed on the cell growth or apoptosis in ER-negative MDA-MB-231 cells. In addition, activities of antioxidant enzymes such as catalase and glutathione peroxidase were decreased effectively after treatment of RA in MCF-7 cells, whereas SOD activity was rarely affected. Thus, the present data suggest that all-trans RA is the most potential inducer of apoptosis and modulator of antioxidant enzymes among RA isomers in MCF-7 human breast cancer cells.

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.59-59
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• 2002

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.153.2-154
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• 2003

Extracts of Artemisia asiatica Nakai (Asteraceae) possess anti-inflammatory and anti-oxidative activities. Eupatilin (5,7-dihydroxy-3,4,6-tri-methoxy-flavone), one of the pharmacologically active ingredients derived from Artemisia asiatica, was shown to induce apoptosis in human promyelocytic leukemia (HL-60) cells (H.-J. Seo and Y.-J. Surh, Mutat. Res., 496, 191-198, 2001). In the present study, we examined the cytostatic effects of eupatilin in H-ras-transformed human breast epithelial (MCF10A-ras) cells. (omitted)

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.214.1-214.1
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• 2001