• Asian Pacific Journal of Cancer Prevention
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• 제15권8호
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• pp.3763-3766
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• 2014

Human mammary epithelial cells have different proliferative statuses and demonstrate a close relationship with age and cell proliferation. Research on this topic could help understand the occurrence, progression and prognosis of breast cancer. In this article, using significance analysis of a microarray algorithm, we analyzed gene expression profiles of human mammary epithelial cells of different proliferative statuses and different age groups. The results showed there were significant differences in gene expression in the same proliferation status between elderly and young groups. Three common differentially expressed genes were found to dynamically change with the proliferation status and to be closely related to tumorigenesis. We also found elderly group had less status-related differential genes from actively proliferating status to intermediate status and more statusrelated differential genes from intermediate status than the young group. Finally, functional enrichment analyses allowed evaluation of the detailed roles of these differentially-expressed genes in tumor progression.

• Animal Bioscience
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• 제36권11호
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• pp.1757-1768
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• 2023

Objective: The number of bovine mammary epithelial cells (BMECs) is closely associated with the quantity of milk production in dairy cows; however, the optimal levels and the combined effects of hormones and essential amino acids (EAAs) on cell proliferation are not completely understood. Thus, the purpose of this study was to determine the optimal combination of individual hormones and EAAs for cell proliferation and related signaling pathways in BMECs. Methods: Immortalized BMECs (MAC-T) were treated with six hormones (insulin, cortisol, progesterone, estrone, 17β-estradiol, and epidermal growth factor) and ten EAAs (arginine, histidine, leucine, isoleucine, threonine, tryptophan, lysine, methionine, phenylalanine, and valine) for 24 h. Results: Cells were cultured in a medium containing 10% fetal bovine serum (FBS) as FBS supplemented at a concentration of 10% to 50% showed a comparable increase in cell proliferation rate. The optimized combination of four hormones (insulin, cortisol, progesterone, and 17β-estradiol) and 20% of a mixture of ten EAAs led to the highest cell proliferation rate, which led to a significant increase in cell cycle progression at the S and G2/M phases, in the protein levels of proliferating cell nuclear antigen and cyclin B1, cell nucleus staining, and in cell numbers. Conclusion: The optimal combination of hormones and EAAs increased BMEC proliferation by enhancing cell cycle progression in the S and G/2M phases. Our findings indicate that optimizing hormone and amino acid levels has the potential to enhance milk production, both in cell culture settings by promoting increased cell numbers, and in dairy cows by regulating feed intake.

• Asian-Australasian Journal of Animal Sciences
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• 제10권2호
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• pp.233-239
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• 1997

A mammary epithelial cell line (MAC-T) established as a model for lactation was utilized to identify and characterize effects of various hormones upon insulin-like growth factor binding protein secretion. Ligand and immunoblot analyses of conditioned media indicated that insulin-like growth factor binding protein-2 was secreted by MAC-T cells. Insulin-like growth factor-I stimulated insulin-like growth factor binding protein-2 secretion in a dose-dependent manner, but prolactin and bovine somatotropin did not alter insulin-like growth factor binding protein-2 secretion. Insulin increased and cortisol decreased insulin-like growth factor binding protein-2 secretion. Effects of insulin-like growth factor-I on insulin-like growth factor binding protein-2 secretion support previous studies using primary cultures of bovine mammary cells and bovine fibroblasts. Effects of cortisol and insulin on insulin-like growth factor binding protein-2 secretion may be explained by changes in protein synthesis. In addition, supraphysiological doses of insulin can cross-react with the insulin-like growth factor-I receptor and stimulate insulin-like growth factor binding protein-2 secretion. MAC-T cells provide a model system to study mechanisms that regulate local insulin-like growth factor-I bioactivity.

• Journal of Animal Science and Technology
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• 제64권5호
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• pp.922-936
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• 2022

5-Hydroxytryptamine (5-HT), a monoamine, as a local regulator in the mammary gland is a chemical signal produced by the mammary epithelium cell. In cows, studies have shown that 5-HT is associated with epithelial cell apoptosis during the degenerative phase of the mammary gland. However, studies in other tissues have shown that 5-HT can effectively promote cell viability. Whether 5-HT could have an effect on mammary cell viability in dairy cows is still unknown. The purpose of this study was to determine: (1) effect of 5-HT on the viability of bovine mammary epithelial cells and its related signaling pathways, (2) interaction between prolactin (PRL) and 5-HT on the cell viability. The bovine mammary alveolar cell-T (MAC-T) were cultured with different concentrations of 5-HT for 12, 24, 48 or 72 hours, and then were assayed using cell counting kit-8, polymerase chain reaction (PCR) and immunobloting. The results suggested that 20 μM 5-HT treatment for 12 or 24 h promote cell viability, which was mainly induced by the activation of 5-HT receptor (5-HTR) 1B and 4, because the increase caused by 5-HT vanished when 5-HTR 1B and 4 was blocked by SB224289 and SB204070. And protein expression of mammalian target of rapamycin (mTOR), eukaryotic translation elongation factor 2 (eEF2), janus kinase 2 (JAK2) and signal transducer and activator of transcription 5 (STAT5) were decreased after blocking 5-HT 1B and 4 receptors. When MAC-T cells were treated with 5-HT and PRL simultaneously for 24 h, both the cell viability and the level of mTOR protein were significantly higher than that cultured with 5-HT or PRL alone. In conclusion, our study suggested that 5-HT promotes the viability of MAC-T cells by 5-HTR 1B and/or 4. Furthermore, there is a reciprocal relationship between PRL and 5-HT.

• 한국식품영양과학회지
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• 제24권3호
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• pp.470-486
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• 1995

유선에 존재하는 유선 상피 모세포(mammary epithelial stem cells)의 존재 증거, 정상 조직에서 이들의역할, flow cytometry 및 면역 염색법에 의한 세포 분리, 세포 기질 단백질을 이용한 삼차원적 세포 배양에서의 증식 등을 요약한다. 유선의 실질 조직에 상피 모세포가 존재한다는 것은 여러 형태의 이식 실험에서 설명되었고 또 모세포의 표현형적 특징들은 여러 가지의 monoclonal antibodies에 의해 논증되었다. 이들 연구의 결과들은 유선의 모세포군이 end bud와 유선의 기저층(basal layer)에 존재한다고 제시하고 있다. 이들을 분리, 동정하기 위해 FITC-PNA와 PE-Thy-1.1 항체와 같은 세포 표지자를 이용하여 유선 상피 세포를 4군으로 나눌 수 있었다. FITC-PNA에만 양성 반응을 보인 PNA+ 세포군, PE-Thy-1.1에만 양성 반응을 보인 Thy-1.1+ 세포군, 이들 두 표지자에 양성 반응을 보인 B+ 세포군, 그리고 양쪽에 음성 반응을 보인 B- 세포군이었는데 이들을 flow cytometry로 분리하고 생체에 이식 실험을 하였을 때 PNA+ 세포군이 유선 모세포들을 가장 많이 가진 것으로 확인되었다. 그리고 유선 상피세포로 이루어진 유선 조직 절편(organoids) 이들 상피세포군을 세포외기질 단백질체인 Matrigel 내에서 배양한 결과 a) stellate, b) duct, c) web, d)squamous, e) lobuloduct 등 5종류의 다세포 구조물이 생성됨을 확인하였다. 이들 중 편평상피화생의 구조물은 정상적인 유선 조직에서는 나타나지 않는 구조물인데 all-trans retinoic acid를 처리하였을 때 배지의 조정에 따라 다소 차이는 있으나 대부분 이들 편평상피화생의 생성이 억제됨을 확인하였다. 이상의 결과로 보아 본 연구에 이용된 생체 이식법 및 삼차원적 세포외기질 세포 배양법이 상피세포의 성장, 분화 및 모세포 연구에 유용하게 이용될 수 있으리라 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권3호
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• pp.414-421
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• 2014

This study was conducted to determine the effects of saturated long-chain fatty acids (LCFA) on cell proliferation and triacylglycerol (TAG) content, as well as mRNA expression of ${\alpha}s1$-casein (CSN1S1) and genes associated with lipid and protein synthesis in bovine mammary epithelial cells (BMECs). Primary cells were isolated from the mammary glands of Holstein dairy cows, and were passaged twice. Then cells were cultured with different levels of palmitate or stearate (0, 200, 300, 400, 500, and 600 ${\mu}M$) for 48 h and fetal bovine serum in the culture solution was replaced with fatty acid-free BSA (1 g/L). The results showed that cell proliferation tended to be increased quadratically with increasing addition of stearate. Treatments with palmitate or stearate induced an increase in TAG contents at 0 to 600 ${\mu}M$ in a concentration-dependent manner, and the addition of 600 ${\mu}M$ was less effective in improving TAG accumulation. The expression of acetyl-coenzyme A carboxylase alpha, fatty acid synthase and fatty acid-binding protein 3 was inhibited when palmitate or stearate were added in culture medium, whereas cluster of differentiation 36 and CSN1S1 mRNA abundance was increased in a concentration-dependent manner. The mRNA expressions of peroxisome proliferator-activated receptor gamma, mammalian target of rapamycin and signal transducer and activator of transcription 5 with palmitate or stearate had no significant differences relative to the control. These results implied that certain concentrations of saturated LCFA could stimulate cell proliferation and the accumulation of TAG, whereas a reduction may occur with the addition of an overdose of saturated LCFA. Saturated LCFA could up-regulate CSN1S1 mRNA abundance, but further studies are necessary to elucidate the mechanism for regulating milk fat and protein synthesis.

• Asian-Australasian Journal of Animal Sciences
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• 제18권12호
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• pp.1741-1745
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• 2005

Zinc is a trace element that is associated with a stimulation of immune function and regulation of ion balance for livestock production. In this study, the effect of zinc as inhibitor to apoptosis-induced cells was examined in vitro using mammary epithelial cell line, HC11 and macrophage cell line, NCTC3749. Cell viability, measured by MTT assay, indicated that 10 g/ml of zinc had a negative impact on cellular activity and 50 ng/ml was chosen for further testing. Apoptosis was induced in cells treated with C2-ceramide in serum-free media. DNA fragmentation and gene expression of acidic sphingomyelinase (a gene responsible for the progress of apoptosis) were distinctively low in zinc treated cells compared with those in non-treated controls. In conclusion, zinc is involved in the regulation of cell proliferation and apoptosis in mammary epithelial cells and macrophages.

• Asian-Australasian Journal of Animal Sciences
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• 제24권4호
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• pp.485-492
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• 2011

The influence of high temperature on mammary cell turnover during the dry period is still unclear. The objective of this study was to investigate mammary cell turnover and p53 protein expression in the mammary tissue under high temperature conditions. Mammary gland biopsy samples from 8 dairy cows were obtained at 7, 25, 40, and 53 d during the dry period in summer or spring (n = 4, each season). Cell cycle, cell turnover, and p53 protein expression were analyzed by flow cytometry. During the dry period in summer, the percentage of mammary epithelial cells in the G0/G1 phase was the highest, but those in the S and G2/M phases were lower. However, the proportion of cells in the different stages of the cell cycle was not significantly different among the different biopsy time points, except in the G2/M phase. Under different temperature conditions, the cells were significantly different in their apoptotic rate and proliferation index; moreover, the tendencies of these indicators to change significantly differed. In general, the samples under high temperature conditions showed significantly lower apoptotic rates and proliferation indices. Under high temperature conditions, the apoptotic rate and proliferation index were the lowest (2.17% and 3.26%, respectively) at day 40, and the highest at day 53 (3.67% and 4.61%, respectively). However, under normal temperature conditions, the values of these indicators were the lowest (7.60% and 5.54%, respectively) at day 7, and almost the highest at day 25 (12.85% and 6.47%, respectively). Moreover, p53 protein expression was significantly higher under high temperature conditions than under normal temperature conditions, except at day 25. The level of p53 protein was the lowest (13.10%) under high temperature conditions at day 25, but was the highest (26.07%) under normal temperature conditions. Our findings suggest that high temperature delayed the G2/M phase of the cell cycle and the cell turnover rate, but remarkably increased p53 protein expression. Thus, the results indicate that high temperature extends the recovery period of mammary epithelial cells.

• 대한수의학회지
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• 제28권2호
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• pp.227-239
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• 1988

In order to investigate the morphological characteristics of dendritic cells in the mammary gland, the appearance on the clear cells(CLs) or ATPase-positive dendritic cells(APDCs) have been observed by the light microscope. The results obtained were summarized as follows: CLs were observed in the mammary tissues of the experimental animals, such as mice, rats, guinea pigs, rabbits, cats, dogs, pigs, cows and Korean native goats, and these CLs were confirmed as the ATPase-positive cells of typical dendritic appearance(APDCs), The APDCs were distributed in between the secretory epithelial cells, between the secretory epithelial cells and the myoepithelial cells, the basal area of the secretory epithelial cells, the interalveolar and interlobular connective tissues, and in between the epithelial cells of secretory duct. The APDCs were observed more frequently during the middle period of lactation than the other periods, and were irregularly or uniformly distributed according to the location. During the middle period of lactation, there were notable quantitative differences in the APDSs depending on the mammary glands of mice, rats, guinea pigs, rabbits and cats, The most prominent differences were recognized among the mice, guinea pigs and cats. The number of AP DCs per unit area was statistically fewer in the guinea pigs($209.07{\pm}51.75cells/mm^2$) than in the mice($221.00{\pm}50.94cells/mm^2$) and cats($223.56{\pm}49.68cells/mm^2$) (respectively, p<0.05, p<0.05). Among the A/J, DBA/2, C57BL/6 and NIH(GP) mice, the mean densities of APDCs was statistically significantly fewer in the DBA/2($196.65{\pm}43.47cells/mm^2$) than in the C57BL/6($248.40{\pm}41.40cells/mm^2$) and NIH(GP) ($235.98{\pm}55.89cells/mm^2$) (respectively, p<0.0000, p<0.0000), however no significant difference between the C57BL/6 and the NIH(GP) was recognized (p>0.1). Among the F344, SD and W rats, the statistical analysis were confirmed that there were significantly fewer APDCs in the F344($198.72{\pm}47.61cells/mm^2$) than in the SD($227.70{\pm}41.40cells/mm^2$) and W($223.56{\pm}49.68cells/mm^2$) (respectively, p<0.0000, p<0.0001), however no significant difference between the SD and the W was recognized(p>0.1). The mean difference between the inbred and the noninbred counts in the mice was statistically significant (p<0.0001), and the similar result was presented in the rats(p<0.0000).

• Asian-Australasian Journal of Animal Sciences
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• 제29권11호
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• pp.1646-1652
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• 2016

Mammalian target of rapamycin complex 1 (mTORC1) is a central regulator of cell growth and metabolism and is sufficient to induce specific metabolic processes, including de novo lipid biosynthesis. Elongation of very-long-chain fatty acids 1 (ELOVL1) is a ubiquitously expressed gene and the product of which was thought to be associated with elongation of carbon (C) chain in fatty acids. In the present study, we examined the effects of rapamycin, a specific inhibitor of mTORC1, on ELOVL1 expression and docosahexaenoic acid (DHA, C22:6 n-3) synthesis in bovine mammary epithelial cells (BMECs). We found that rapamycin decreased the relative abundance of ELOVL1 mRNA, ELOVL1 expression and the level of DHA in a time-dependent manner. These data indicate that ELOVL1 expression and DHA synthesis are regulated by mTORC1 in BMECs.