Regulation of HIF-1α Stability through S-Nitrosylation

• DOI: 10.1016/j.molcel.2007.02.024
• Publication Date: 2007-04-13T11:49:02Z
• Authors: Fang Li; Pierre Sonveaux; Zahid N. Rabbani; Shanling Liu; Bin Yan; Qian Huang; Zeljko Vujaskovic; Mark W. Dewhirst; Chuan-Yuan Li
• Keywords: 0303 health sciences; Sequence Homology, Amino Acid; Macrophages; Molecular Sequence Data; Nitric Oxide Synthase Type II; Cell Biology; Hypoxia-Inducible Factor 1, alpha Subunit; Nitric Oxide; Transfection; Models, Biological; Gene Expression Regulation, Neoplastic; Mice; 03 medical and health sciences; Cell Line, Tumor; Neoplasms; Mutation; Animals; Amino Acid Sequence; Cysteine; signaling; Molecular Biology; Cells, Cultured

Hypoxia-inducible factor 1 (HIF-1) is a master transcriptional factor. Under normal oxygen tension, HIF-1 activity is usually suppressed due to the rapid, oxygen-dependent degradation of one of its two subunits, HIF-1alpha. Here we report that normoxic HIF-1 activity can be upregulated through NO-mediated S-nitrosylation and stabilization of HIF-1alpha. In murine tumors, exposure to ionizing radiation stimulated the generation of NO in tumor-associated macrophages. As a result, the HIF-1alpha protein is S-nitrosylated at Cys533 (through "biotin switch" assay) in the oxygen-dependent degradation domain, which prevents its destruction. Importantly, this mechanism appears to be independent of the prolylhydroxylase-based pathway that is involved in oxygen-dependent regulation of HIF-1alpha. Selective disruption of this S-nitrosylation significantly attenuated both radiation-induced and macrophage-induced activation of HIF-1alpha. This interaction between NO and HIF-1 sheds new light on their involvement in tumor response to treatment as well as mammalian inflammation process in general.