• Archives of Pharmacal Research
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• v.20 no.6
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• pp.566-571
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• 1997

To gain further insight into how estrogens modulate cell function, the effects of estrogen on cell proliferation were studied inhuman breast cancer cells. We examined the effects of estrogen on the proliferation of three human breast cancer cell lines that differed in their estrogen receptor contents. Ten nM estradiol markedly stimulated the proliferation of MCF-7 human breast cancer cells that contained high levels of estrogen receptor $1.15{\pm}0.03 pmole/mg protein)$(over that of control. In T47D cells that contained low levels of estrogen receptor $0.23{\pm}0.05 pmole/mg protein)$, Ten nM estrogen slightly stimulated the proliferation over that of control. MDA-MB-231 cells, that contained no detectable levels of estrogen receptors, had their growth unaffected by estrogen. These results showed their sensitivity to growth stimulation by estrogen correlated well with their estrogen receptor content. Also we examined the effect of estrogen on cellular progesterone receptor level as well as plasminogen activator activity in MCF-7 cells. Ten nM estradiol showed maximal stimulation of progesterone receptor level as well as plasminogen activator activity in MCF-7 cells. It is not clear whether these stimulations of progesterone receptor and plasminogen activator activity by estrogen are related to the estrogen stimulation of cell proliferation of MCF-7 cells. Studies with estrogen in human breast cancer cells in culture indicate that sensitivity to growth stimulation by estrogen correlates well with estrogen receptor contents.

• Biomedical Science Letters
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• v.25 no.1
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• pp.23-31
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• 2019

The protein kinase $CK2{\alpha}$ (formerly Casein Kinase II) is implicated in tumorigenesis and transformation. However, the mechanisms of $CK2{\alpha}$ activation in breast cancer have yet to be elucidated. This study investigated the mechanisms of $CK2{\alpha}$ activation in estrogen signaling. Estrogen increased reactive oxygen species (ROS) production, $CK2{\alpha}$ activity, and protein expression in estrogen receptor positive ($ER^+$) MCF-7 human breast cancer cells, which were inhibited by the antioxidant N-acetyl-L-cysteine. $H_2O_2$ enhanced $CK2{\alpha}$ activity and protein expression. Human epidermal growth factor (EGF) increased ROS production, $CK2{\alpha}$ activity and protein expression in EGF receptor 2 (HER2)-overexpressing MCF-7 (MCF-7 HER2) cells, but not in MCF-7 cells. Estrogen induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK). The p38 inhibitor, SB202190, blocked estrogen-induced increases in ROS production, $CK2{\alpha}$ activity and $CK2{\alpha}$ protein expression. The data suggest that ROS/p38 MAPK is the key inducer of $CK2{\alpha}$ activation in response to estrogen or EGF.

• Archives of Pharmacal Research
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• v.20 no.6
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• pp.572-578
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• 1997

To gain further insight into how antiestrogens modulate cell function, the effects of antiestrogen on cell proliferation were studied in human breast cancer cells. We examined the effects of trans-tamoxifen on the proliferation of three human breast cancer cell lines that differed in their estrogen receptor contents. Trans-tamoxifen $(1{\mu}M)$ markedly inhibited the estrogen stimulated proliferation of MCF-7 human breast cancer cells that contained high levels of estrogen receptor $(1.15{\pm}0.03 pmole/mg protein)$ over that of control. In T47D cells that contained low levels of estrogen receptor $(0.23{\pm}0.05 pmole/mg protein)$, trans-tamoxifen $(1{\mu}M)$ showed minimal inhibition of estrogen stimulated cell proliferation over that of control. MDA-MB-231 cells, that contained no detectable levels of estrogen receptors, had their growth unaffected by trans-tamoxifen treatment. These results showed their sensitivity to growth inhibition by antiestrogen conrrelated well with their estrogen receptor content. Also we examined the effect of antiestrogen on cellular progestrone receptor level as well as plasminogen activator activity in MCF-7 cells. Trans-tamoxifen $(1{\mu}M)$ showed maximal inhibition of estrogen stimulated progestrone receptor level as well as plasminogen activator activity in MCF-7 cells that were stimulated by estrogen. It is not clear whether these inhibitions of progestrone receptor and plasminogen activator activity by estrogen are related to the antiestrogen inhibition of cell proliferation of MCF-7 cells. From the results of this study, it is clearly demonstrated that trans-tamoxifen is an antiestrogen in MCF-7 human breast cancer cells. Our data suggest that the biological effectiveness of trans-tamoxifen appear to result from its affinity of interaction with the estrogen receptor.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.114-114
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• 2003

Ginseng is a medicinal herb widely used in Asian countries, and its pharmacological effects has been demonstrated in various systems such as cardiovascular, central nervous, and endocrine systems. Its effects are mainly attributed to the ginsenosides. We hypothesize that a component of Panax ginseng, ginsenoside-Rbl, acts by binding to estrogen receptor. We have investigated the estrogenic activity of ginsenoside-Rbl in a transient transfection system using estrogen receptors ${\alpha}$ or ${\beta}$ with estrogen -responsive luciferase plasmids in COS monkey kidney cells. Ginsenoside-Rbl activated both estrogen receptors ${\alpha}$ and ${\beta}$ in a dose-dependent manner (0.5 -100 M ). Activation was inhibited by the specific estrogen receptor antagonist ICI 182,780, indicating that the estrogenic effect of ginsenoside-Rbl is estrogen receptor dependent. Next, we evaluated the ability of ginsenoside-Rbl to induce estrogen-responsive progesterone receptor gene by semi-quantitative RT-PCR assays. MCF-7 cells treated with l7${\beta}$-estradiol or ginsenoside- Rb1 exhibited an increased expression of progesterone receptor mRNA. However, ginsenoside-Rbl failed to displace the specific binding of ［3H］17${\beta}$-estradiol to estrogen receptor in MCF-7 cells as examined by whole cell ligand binding assays, suggesting that there is no direct interaction of ginsenoside-Rbl with estrogen receptor. Our results indicate that estrogen-like activity of ginsenoside-Rbl is independent of direct estrogen receptor association.

• Fisheries and Aquatic Sciences
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• v.5 no.4
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• pp.251-257
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• 2002

Effects of bisphenol-A (BPA) on vitellogenin (VTG) synthesis and estrogen-estrogen receptor $(E_2- ER)$ binding activity were examined in primary hepatocyte cultures of rainbow trout, Oncorhynchus mykiss. Hepatocytes were precultured for 2 days and then $estradiol-17\beta\;(E_2,\;2\times10^{-6}M)\;BPA\;(10^{-5}-10^{-8}M)$ and/or 4-hydroxy-tamoxifen $(4-OHT,\;10^{-6} M)$ were simultaneously added to the incubation medium. Hepatocytes were cultured for 5 more days and then spent medium was analyzed by SDS-PAGE for VTG production. The addition of BPA to the incubation medium had no effect on the viability of hepatocytes in the culture. On the other hand, BPA increased VTG production in a concentration-dependent way and a significant increment occurred at BPA concentrations greater than $10^{-6}$M. Although VTG was increased by the addition of $E_2\;(2\times10^{-6}\;M)\;or\;BPA\;(10^{-5}M)$, its were reduced by a simultaneous 4-OHT $(10^{-6}\;M)$ addition. BPA inhibited $E_2-human$ ER binding activity by $72\%$ at $10^{-5}$ M of BPA. These results suggested that BPA induced VTG synthesis by BPA-ER binding activity in the hepatocyte of rainbow trout.

• Toxicological Research
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• v.33 no.1
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• pp.71-77
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• 2017

Hormone replacement therapy (HRT) consists of highly effective prescription medications for treating menopausal symptoms; however, these agents have exhibited side effects including the risk of estrogen-induced carcinogenesis. Therefore, interest in phytotherapy-based materials as a natural source of alternatives to estrogen therapy has increased. However, some of these herbal medicines have been reported to increase the risk of estrogen-induced cancer. Herbal formulations composed of a combination of Cynanchum wilfordii Hemsley (CW), Phlomis umbrosa Turczaninow (PU), and Angelica gigas Nakai (AG) extracts (CPAE) have been used for treating menopausal symptoms. Therefore, in this study, we aimed to examine the safety of CPAE by determining its potential adverse estrogenic activity using the Organization for Economic Cooperation and Development (OECD) test guideline 455 (TG455) in a stably transfected transcriptionally activated human estrogen receptor ${\alpha}$ ($hER{\alpha}$)-HeLa9903 cell model. We found that CPAE did not how any estrogenic activity or stimulate promoters containing estrogen response elements in MCF-7 cells. In addition, CPAE showed no significant selective activity against $hER{\alpha}$ and $hER{\beta}$, non-selective activity against the ER, or effects on ER target gene expression. Furthermore, CPAE did not significantly induce MCF-7 cell proliferation and uterine weight increase in ovariectomized rats. These results demonstrate that CPAE can be used as beneficial herbal drug for prevention and therapeutic intervention of estrogen carcinogenesis in menopausal women.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.322-326
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• 2005

IgE-dependent histamine-releasing factor (HRF) is found extracellularly to regulate the degranulation process of histamine in mast cells and basophils and known to play a predominant role in the pathogenesis of chronic allergic disease. HRF has been also identified in the intracellular region of the cell. Previously, we reported that HRF interacts with the 3rd cytoplasmic domain of the alpha subunit of Na,K-ATPase and inhibits Na,K-ATPase activity. Since it is known that estroaen activates the sarcolemmal Na,K-ATPase, we tested whether estrogen recovers the Na,K-ATPase activity repressed by HRF. In this study, we showed that estrogen activates Na,K-ATPase repressed by HRF. RT-PCR and western blot analysis showed that estrogen doesn't reduce the expression level of HRF in HeLa cell, suggesting that this recovery effects of estrogen probably occur via indirect mechanism on HRF and Na,K-ATPase.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.3
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• pp.41-49
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• 1994

This study was intended to investigate the effects of nutritional, physical and environmental conditions on the bone status of 102 pre and post menopausal women living in Ulsan area. The results of this study are summarized as follows : when subjects were classified into two groups by bone status, there were significant differences in age, calcium index, serum estrogen and physical activity between two groups. Average daily calcium intake of subjects was 682.9 (149.2)mg, which is almost same as RDA, but 41.1% of the subjects consumed calcium below RDA. Calcium index(p<0.05), serum estrogen(p<0.001), physical activity(p<0.001) of poor bone group were significantly lower than those of good bone group. Although there was not a significant difference between bone status and other influential factors, such as family type, skip meal, alcohol drinking, smoking and BMI, each has been shown to have an effect, if slight, on the bone status.

• Journal of Nutrition and Health
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• v.24 no.1
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• pp.30-39
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• 1991

This study was designed to investigate the effects of dietary calcium. serum estrogen level and physical activity on the bone status of 116 healthy elderly women living in urban area. Current calcium intake was assessed by convenient method(refered to as Ca intake) and calcium containing food frequency method(refered to as Ca index) Daily activity record was used for the estimation of physical activity level, and serum estrogen level was measured from fasting blood of subjects. The rate of bone resorption was evaluated by the determination of hydroxyproline(Hpr) in fasting urine with correction for creatinine excretion. The results of this study are summarized as follows : 1) Average daily Ca intake of subjects was 621.4$\pm$155.8mg, which is above the Korean recommended dietary allowances. However 44.8% of the subjects consumed Ca below RDA level. Ca index score was significantly correlated with the bone status(P<0.05), Ca intake did not show significant correlation with the bone status although a positive trend of influence was evident. 2) Average serum estrogen level of subjects was 18.7$\pm$9.8pg Contrary to our anticipation. estrogen level did not show any significant relation to age and bone status. 3) Daily physical activity was classified into four categories by activity intensity : sedentary. moderate, active and severe. The average physical activity of subjects belong to moderate level. and the bone status was significantly related to the physical activity(P<0.01) 4) Among other influential factors such as age, pocket-money. family type. drinking, smoking and BMI, there was a significant difference between bone status and BMI(P<0.05). 5) Multiple regression analysis of variables showed that physical activity has greater effect than other variables when the entire subjects were taken into account. However. eliminating the subjects whose bone status rated as excellent(Hpr/cr<0.009), Ca index showed higher correlation than physical activity. These results have demonstrated that dietary calcium intake is the primary important factor for keeping good bone health and that bone status of subjects with a sufficient calcium intake is affected by various factors such as physical activity, age, smoking. BMI and others.

• Archives of Pharmacal Research
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• v.27 no.5
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• pp.554-561
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• 2004

Trichostatin A, an antifungal antibiotics, and HC-toxin are potent and specific inhibitors of histone deacetylase activity. Histone deacetylase inhibitors are new class of chemotherapeutic drugs able to induce tumor cell apoptosis and/or cell cycle arrest. In this study, the antiproliferative activities of trichostatin A and HC-toxin were compared between estrogen receptor positive human breast cancer cell MCF-7 and estrogen receptor negative human breast cancer cell MDA-MB-468. Trichostatin A and HC-toxin showed potent antiproliferative activity in both MCF-7 and MDA-MB-468 cells. In MCF-7 cells that contain high level estrogen receptor, trichostatin A and HC-toxin brought about three-times more potent cell growth inhibitory effect than estrogen receptor negative MDA-MB-468 cells. Both trichostatin A and HC-toxin showed cell cycle arrest at G$_2$/M phases of MCF-7 and MDA-MB-468 cells in a dose- and time- depen- dent manner. Trichostatin A and HC-toxin also induced apoptosis from MCF-7 and MDA-MB-468 cells in a dose- and time-dependent manner. Results of this study suggested that antipro-liferative effects of trichostatin A and HC-toxin might be involved in estrogen receptor signaling pathway, but cell cycle arrest and apoptosis of trichostatin A and HC-toxin might not be involved in estrogen receptor system of human breast cancer cells.