Department of Bioscience and Biotechnology, College of Life Science, Institute of Biotechnology, Sejong University, Kwangjingu, Kunjadong, Seoul 143-747, Republic of Korea.
Department of Bioscience and Biotechnology, College of Life Science, Institute of Biotechnology, Sejong University, Kwangjingu, Kunjadong, Seoul 143-747, Republic of Korea.
Biochem Biophys Res Commun. 2014 Jul 18;450(1):261-6. doi: 10.1016/j.bbrc.2014.05.107. Epub 2014 Jun 2.
Estrogen receptor (ER) β is predicted to play an important role in the prevention of breast cancer development and progression. We have previously shown that ERβ suppresses hypoxia inducible factor (HIF)-1-mediated transcription through aryl hydrocarbon receptor nuclear translocator (ARNT) degradation via ubiquitination processes. In this study, we attempted to examine the effect of ERβ specific ligand on HIF-1 inhibition in ERβ positive PC3 cells and ERβ transfected MCF-7 cells. ERβ specific agonist diarylpropionitrile (DPN) stimulated estrogen response element (ERE)-luciferase activity in a similar fashion to estradiol in PC3 cells. We observed that DPN down-regulates the ARNT protein levels leading to an attenuation of hypoxia-induced hypoxia response element (HRE)-driven luciferase reporter gene activation in PC3 cells. Treatment of DPN reduced vascular endothelial growth factor (VEGF) expression and co-treatment with ERβ specific antagonist PHTPP abrogated the effect in PC3 cells. We then examined the effect of DPN in ERβ transfected MCF-7 cells. HIF-1 transcriptional activity repression by ERβ was not further reduced by DPN, as examined by HRE-driven luciferase assays. Expression of ERβ significantly decreased VEGF secretion and ARNT expression under hypoxic conditions. However, DPN did not additionally affect this suppression in MCF-7 cells transfected with ERβ. This result shows that unliganded ERβ is sufficient to inhibit HIF-1 in systems of overexpression.
雌激素受体 (ER)β 被预测在预防乳腺癌的发生和发展中发挥重要作用。我们之前已经表明，ERβ 通过泛素化过程促进芳香烃受体核转位蛋白 (ARNT) 降解来抑制缺氧诱导因子 (HIF)-1 介导的转录。在这项研究中，我们试图研究 ERβ 特异性配体对 ERβ 阳性 PC3 细胞和 ERβ 转染 MCF-7 细胞中 HIF-1 抑制的影响。ERβ 特异性激动剂二苯丙腈 (DPN) 以类似于雌二醇的方式刺激 PC3 细胞中的雌激素反应元件 (ERE)-荧光素酶活性。我们观察到 DPN 下调 ARNT 蛋白水平，导致 PC3 细胞中缺氧诱导的缺氧反应元件 (HRE)-驱动的荧光素酶报告基因激活减弱。DPN 处理降低了血管内皮生长因子 (VEGF) 的表达，并且在 PC3 细胞中用 ERβ 特异性拮抗剂 PHTPP 共同处理则消除了这种作用。然后，我们在 ERβ 转染的 MCF-7 细胞中检查了 DPN 的作用。通过 HRE 驱动的荧光素酶测定，发现 ERβ 对 HIF-1 转录活性的抑制作用并未因 DPN 而进一步降低。在低氧条件下，ERβ 的表达显著降低了 VEGF 的分泌和 ARNT 的表达。然而，DPN 并没有进一步影响 ERβ 转染的 MCF-7 细胞中的这种抑制作用。该结果表明，在过表达系统中，未配体结合的 ERβ 足以抑制 HIF-1。
