KMID : 0613820030130030314
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Journal of Life Science 2003 Volume.13 No. 3 p.314 ~ p.323
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Min Gye-Sik
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Abstract
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The purpose of this study was to examine the effects of xenobiotic nuclear receptors, CAR, SXR, and PPAR¥ã on the transcriptional activity of estrogen receptor in human breast cancer cell lines and compare with those in human hepatoma cell line. Two different breast cancer cell lines, MCF-7 and MDA-MB-231 were cultured and effects of CAR, SXR, and PPAR¥ãon the ER-mediated transcriptional activation of synthetic (4ERE)-tk-luciferase reporter gene were analyzed. Consistent with the previous report, CAR significantly inhibited ER-mediated transactivation and SXR repressed modestly whereas the PPAR¥ã did not repress the ER-mediated transactivation. However, in breast cancer cells neither of the xenobiotic receptors repressed the ER-mediated transactivation. Instead, they tend to increase the transactivation depending on the cell type and xenobiotic nuclear receptors. In MCF-7, SXR but neither CAR nor PPAR¥ã slightly increased ER-mediated transactivation whereas in MDA-MB-231, CAR and PPAR¥ã but not SXR tend to increase the transactivation of the reporter gene. These results indicate that the effects of ER cross-talk by the CAR, SXR, and PPAR¥ã, are different in breast cancer cells from hepatoma cells. In conclusion, the transcriptional regulation by estrogen can involve different cross-talk interaction between estrogen receptor and xenobiotic nuclear receptors depending on the estrogen target cells.
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KEYWORD
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Estrogen Receptor, CAR, SXR, PPAR¥ã, Breast Cancer Cells
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