Feng Wenke, Ye Fei, Xue Wanli, Zhou Zhanxiang, Kang Y James
Departments of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA.
Mol Pharmacol. 2009 Jan;75(1):174-82. doi: 10.1124/mol.108.051516. Epub 2008 Oct 8.
Previous studies have demonstrated that copper up-regulates hypoxia-inducible factor 1 (HIF-1). The present study was undertaken to test the hypothesis that copper is required for HIF-1 activation. Treatment of HepG2 cells with a copper chelator tetraethylenepentamine (TEPA) or short interfering RNA targeting copper chaperone for superoxide dismutase 1 (CCS) suppressed hypoxia-induced activation of HIF-1. Addition of excess copper relieved the suppression by TEPA, but not that by CCS gene silencing, indicating the requirement of copper for activation of HIF-1, which is CCS-dependent. Copper deprivation did not affect production or stability of HIF-1alpha but reduced HIF-1alpha binding to the hypoxia-responsive element (HRE) of target genes and to p300, a component of HIF-1 transcriptional complex. Copper probably inhibits the factor inhibiting HIF-1 to ensure the formation of HIF-1 transcriptional complex. This study thus defines that copper is required for HIF-1 activation through the regulation of HIF-1alpha binding to the HRE and the formation of the HIF-1 transcriptional complex.
先前的研究表明，铜可上调缺氧诱导因子1（HIF-1）。本研究旨在验证铜是HIF-1激活所必需的这一假说。用铜螯合剂三亚乙基四胺（TEPA）或靶向超氧化物歧化酶1铜伴侣（CCS）的短发夹RNA处理HepG2细胞，可抑制缺氧诱导的HIF-1激活。添加过量铜可缓解TEPA的抑制作用，但不能缓解CCS基因沉默的抑制作用，这表明铜是HIF-1激活所必需的，且这种激活依赖于CCS。铜缺乏并不影响HIF-1α的产生或稳定性，但会降低HIF-1α与靶基因缺氧反应元件（HRE）以及与HIF-1转录复合物组分p300的结合。铜可能抑制了抑制HIF-1的因子，以确保HIF-1转录复合物的形成。因此，本研究明确了铜通过调节HIF-1α与HRE的结合以及HIF-1转录复合物的形成来激活HIF-1。
