• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.145-145
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• 2002

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a prototype and the most potent chemical of the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (dioxins). A variety of studies on the toxic effects of dioxin and related compounds have been conducted internationally since 1990.(omitted)

• Korean Journal of Animal Reproduction
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• v.17 no.1
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• pp.49-56
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• 1993

Mouse mammary epithelial cells(NMuMG) were plated onto 24 well phates(100,000 cells/well), in DMEM supplemented with 10% fetal calf serum. After serum starvation for 24 hours, EGF)0~100ng/ml) was added simultaneously with IGF-I(10ng/ml), 1$\mu$M photoreactive cAMP(4,5-dimethoxy-2-nitrobenzyl adenosine-3',5' cyclic monophosphate, DMNB) or IGF-I plus DMNB. After 2 hours, the cells were expposed to UV light(300nm, 3 second pulse0 in order to activate DMNB which induces a rapid transient increase in intracellular cAMP upon UV irradiation. DNA synthesis was estimated as incorporation of 3H-thymidine into DNA(1 hour pulse with 1$\mu$Ci/ml, 18~19 hours after UV exposure). Without IGF-I or DMNB, EGF(10 or 100ng/ml) increased DNA synthesis from 8,362 dpm/well in control to 16,345 or 18,684 dpm/well with EGF(pooled SE=1,239 dpm/well, P<0.05). IGF-I or IGF-I plus DMNB alone increased DNA synthesis from 8,362 dpm/well in control to 17,307 or 20,427 dpm/well, respectively(P<0.05). Addition of IGF-I, DMNB or IGF-I plus DMNB into 0~100ng/ml EGF did not significantly change the shape of dose response curve of EGF alone. In other experiment, EGF or IGF-I plus DMNB into 10ng/ml EGF group exhibited interaction effect in DNAsynthesis [EGF(10ng/ml)=18,497; IGF-I＋EGF=22,837; DMNB＋EGF=20,658 ; IGF-I＋DMNB＋EGF=29,658, pooled SE=1,055, P<0.05]. These results indicate that simultaneous activation of EGF, IGF-I and intracellular cAMP interact in DNA synthesis of mouse mammary epithelial cells.

• 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)

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.878-885
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• 2017

Objective: Glucose is an essential fuel in the energy metabolism and synthesis pathways of all mammalian cells. In lactating animals, glucose is the major precursor for lactose and is a substrate for the synthesis of milk proteins and fat in mammary secretory (alveolar) epithelial cells. However, clear utilization of glucose in mammary cells during lactogenesis is still unknown, due to the lack of in vitro analyzing models. Therefore, the objective of this study was to test the reliability of the mammary alveolar (MAC-T) cell as an in vitro study model for glucose metabolism and lactating system. Methods: Undifferentiated MAC-T cells were cultured in three types of Dulbecco's modified Eagle's medium with varying levels of glucose (no-glucose: 0 g/L, low-glucose: 1 g/L, and high-glucose: 4.5 g/L) for 8 d, after which differentiation to casein secretion was induced. Cell proliferation and expression levels of apoptotic genes, Insulin like growth factor-1 (IGF1) receptor, oxytocin receptor, ${\alpha}S1$, ${\alpha}S2$, and ${\beta}$ casein genes were analyzed at 1, 2, 4, and 8 d after differentiation. Results: The proliferation of MAC-T cells with high-glucose treatment was seen to be significantly higher. Expression of apoptotic genes was not affected in any group. However, expression levels of the mammary development related gene (IGF1 receptor) and lactation related gene (oxytocin receptor) were significantly higher in the low-glucose group. Expressions of ${\alpha}S1-casein$, ${\alpha}S2-casein$, and ${\beta}-casein$ were also higher in the low-glucose treated group as compared to that in the no-glucose and high-glucose groups. Conclusion: The results demonstrated that although a high-glucose environment increases cell proliferation in MAC-T cells, a low-glucose treatment to MAC-T cells induces higher expression of casein genes. Our results suggest that the MAC-T cells may be used as an in vitro model to analyze mammary cell development and lactation connected with precise biological effects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1701-1707
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• 2012

3,3'-Diindolylmethane (DIM) is a major in vivo derivative of the putative anticancer agent indole-3-carbinol, which is present in cruciferous vegetables and has been reported to have anti-carcinogenic properties. An abnorrmally elevated level of cyclooxygenase-2 (COX-2) has been implicated in the pathogenesis of carcinogenesis. To investigate the mechanism by which DIM exhibits anti-carcinogenic effects, we investigated the effects of DIM on COX-2 expression in MCF-10A human mammary epithelial cells treated with the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA). DIM inhibited TPA-induced COX-2 expression and suppressed the synthesis of prostaglandin $E_2$, one of the major products of COX-2. Nuclear factor-kappa B ($NF-{\kappa}B$) is a transcription factor known to play a role in regulation of COX-2 expression. Treatment of MCF-10A cells with TPA increased nuclear translocation of phospho-p65, with the maximal levels being reached at 1 hour, while DIM inhibited the TPA-induced nuclear translocation of phospho-p65. Overall, we demonstrated that DIM suppresses phorbol ester-induced $PGE_2$ production and COX-2 expression in MCF-10A cells. The reduction in COX-2 levels by DIM maybe mediated through inhibition of $NF-{\kappa}B$ signaling.

• Journal of Animal Science and Technology
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• v.64 no.1
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• pp.110-122
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• 2022

The reduction of milk yield caused by heat stress in summer is the main condition restricting the economic benefits of dairy farms. To examine the impact of hyperthermia on bovine mammary epithelial (MAC-T) cells, we incubated the MAC-T cells at thermal-neutral (37℃, CON group) and hyperthermic (42℃, HS group) temperatures for 6 h. Subsequently, the cell viability and apoptotic rate of MAC-T cells, apoptosis-related genes expression, casein and amino acid transporter genes, and the expression of the apoptosis-related proteins were examined. Compared with the CON group, hyperthermia significantly decreased the cell viability (p < 0.05) and elevated the apoptotic rate (p < 0.05) of MAC-T cells. Moreover, the expression of heat shock protein (HSP)70, HSP90B1, Bcl-2-associated X protein (BAX), Caspase-9, and Caspase-3 genes was upregulated (p < 0.05). The expression of HSP70 and BAX (pro-apoptotic) proteins was upregulated (p < 0.05) while that of B-cell lymphoma (BCL)2 (antiapoptotic) protein was downregulated (p < 0.05) by hyperthermia. Decreased mRNA expression of mechanistic target of rapamycin (mTOR) signaling pathway-related genes, amino acid transporter genes (SLC7A5, SLC38A3, SLC38A2, and SLC38A9), and casein genes (CSNS1, CSN2, and CSN3) was found in the heat stress (HS) group (p < 0.05) in contrast with the CON group. These findings illustrated that hyperthermia promoted cell apoptosis and reduced the transport of amino acids into cells, which inhibited the milk proteins synthesis in MAC-T cells.

• Toxicological Research
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• v.16 no.4
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• pp.275-284
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• 2000

The organ culture model of the whole mammary gland has many advantages for the study of branching morphogenesis and biological characteristics, including tumorigenesis. Prior to whole gland organ culture, rats were treated with 7,12-dimethylbenz[a]anthracene (DMBA) or N-methyl-N-nitrosourea (MNU) for one week. The tramdorming effect and the morphological changes were assessed by the whole mount preparations and histopathological examination in terminal end buds (TEB), terminal ducts (TD), alveolar buds (AB), alveolar lobules (AL) and hyperplastic alveolar nodules (HAN) of the mammary gland. Grossfindings of the mammary glands at dissection were higher branching morphogenesis and larger volume in carcinogen-treated groups than in carcinogen-non-treated groups. Results of the whole mount method were coincided with those of the histopathological observations. Circular TEB, normally maintained AB, AL, and high cellular density were more frequently observed in carcinogen-treated groups than in carcinogen-nan-treated groups. Histopathologically, as a preneoplastic marker, HAN was maintained only in mammary organ culture of the carcinogen-treated groups. These findings suggest that in vivo trans-formation effects by carcinogens persisted during the mammary organ culture. These results were more characteristic in DMBA than in MNU-treated group. Ducts and terminal ducts appeared to have lost morphology during their growths in case of without diethylstilbestrol (DES). The fact that in vitro organ culture without DES was resulted in abnormal ductular morphogenesis confirms that DES is a physiological regulator of ductular epithelial cell growth.

• Journal of Veterinary Clinics
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• v.9 no.2
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• pp.457-466
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• 1992

An 11 years old Irish Setter bitch was euthanlzed and necropsied because of clinical findings such as severe purulent nasal discharge and formation of large tumor mass, 8 ${\times}$8cm in size, in the abdominal cavity. A complete unilateral mastectomy had been carried out twice 14 and 22 months before necropsy. The surgically removed masess of the mammary glands had been diagnosed as malignant mixed tumor in each time. Grossly, tumor masses were observed in nasal cavity, infralumbar lymph node, lung, abdominal cavityn and brain. Microscopic findings of the surgically removed masses consisted of tumor epithelial cells, tumor hyaline cartilage-like structures and abundant connective tissues. The mass of the lymph node had similar microscopic features to those of the original malignant mixed tumor of the mammary glands. The tumor osseous tissue and osteoid were observed in the abdominal cavity, lung, and brain. Myoepithelial cells were frequently found on association with the metastatic tumors. From the results, it was concluded that malignant mixed tumor of the mammary glands metastasized to the infralunbar lymph node, abdominal cavity, lung and brain. In addition, the observation in this study supported two theories at the same time that the bone in malignant mixed tumor arises by endochondral ossification of the cartilage formed by the myoepithelial cells and arises by intramembranous ossification of stromal connective tissue or transformed myeopithelial cells. Solid carcinoma of the nasal epielia and granulosa cell tumor were also diagnosed in a mass of the nasal cavity and of the ovaries respectively.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.94-94
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• 2002

Lactadherin (formerly known as BA46), a major glycoprotein of the human milk fat globule membrane, is abundant in human breast milk and breast carcinomas and may prevent symptomatic rotavirus infections. In this study, under the control of mouse whey acidic protein (WAP) promoter, the expression pattern of lactadherin (Ltd) in lactogenic hormone-dependent mouse mammary epithelial cell line HC11 were tested. pLNWLtd construct containing 2.4 kilobases of the WAP promoter and 1.5 kilobases of human lactadherin gene was stably transfered into HC11 cells using retroviral vector system. Integration and expression level of the transgene was estimated using PCR and RT-PCR, respectively. Prominent induction of Ltd gene under the WAS promoter was accomplished in the presence of insulin, hydrocortisone and prolactin, while induction with insulin alone resulted in lower expression. Our results demonstrate that the expression of the transgene is increased by synergistic effect of several lactogenic hormones, including insulin, hydrocortisone, and prolactin.

• Journal of Animal Science and Technology
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• v.64 no.3
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• pp.481-499
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• 2022

This study aims to determine the effects of D-methionine (D-Met) isomer and the methionine precursor 2-hydroxy-4-methylthiobutanoic acid i (HMBi) supplementation on milk protein synthesis on immortalized bovine mammary epithelial cell (MAC-T). MAC-T cells were seeded using 10-cm dishes and cultured in Dulbecco's modified Eagle's medium/F12 (DMEM/F12) basic medium. The basic medium of DMEM/F12 was replaced with the lactogenic DMEM/ F12 differentiation medium when 90% of MAC-T cells reached confluency. The best dosage at 0.6 mM of D-Met and HMBi and incubation time at 72 h were used uniformly for all treatments. Each treatment was replicated six times wherein treatments were randomly assigned in a 6-well plate. Cell, medium, and total protein were determined using a bicinchoninic acid protein assay kit. Genes, proteomics and metabolomics analyses were also done to determine the mechanism of the milk protein synthesis pathway. Data were analyzed by two-way analysis of variance (ANOVA) with supplement type and plate as fixed effects. The least significant difference test was used to evaluate the differences among treatments. The HMBi treatment group had the highest beta-casein and S6 kinase beta-1 (S6K1) mRNA gene expression levels. HMBi and D-Met treatments have higher gene expressions compared to the control group. In terms of medium protein content, HMBi had a higher medium protein quantity than the control although not significantly different from the D-Met group. HMBi supplementation stimulated the production of eukaryotic translation initiation factor 3 subunit protein essential for protein translation initiation resulting in higher medium protein synthesis in the HMBi group than in the control group. The protein pathway analysis results showed that the D-Met group stimulated fructose-galactose metabolism, glycolysis pathway, phosphoinositide 3 kinase, and pyruvate metabolism. The HMBi group stimulated the pentose phosphate and glycolysis pathways. Metabolite analysis revealed that the D-Met treatment group increased seven metabolites and decreased uridine monophosphate (UMP) production. HMBi supplementation increased the production of three metabolites and decreased UMP and N-acetyl-L-glutamate production. Taken together, D-Met and HMBi supplementation are effective in stimulating milk protein synthesis in MAC-T cells by genes, proteins, and metabolites stimulation linked to milk protein synthesis.