title: Hypoxia-inducible factor induction by tumour necrosis factor in normoxic cells requires receptor-interacting protein-dependent nuclear factor kappa B activation.
abstract: Tumour necrosis factor alpha (TNF-alpha) binds to its receptor (TNFR1) and activates both death- and inflammation/survival-related signalling pathways. The inflammation and survival-related signalling cascade results in the activation of the transcription factor, nuclear factor kappa B (NF-kappa B) and requires recruitment of receptor-interacting protein (RIP) to TNFR1. The indispensable role of RIP in TNF-induced NF-kappa B activation has been demonstrated in RIP(-/-) mice and in cell lines derived from such mice. In the present study, we show that the TNF-alpha-induced accumulation of hypoxia-inducible factor 1 alpha (HIF-1 alpha) protein in normoxic cells is RIP-dependent. Exposing fibroblasts derived from RIP(-/-) mice to either cobalt or PMA resulted in an equivalent HIF-1 alpha induction to that seen in RIP(+/+) fibroblasts. In contrast, RIP(-/-) cells were unable to induce HIF-1 alpha in response to TNF-alpha. Further, transient transfection of NIH 3T3 cells with an NF-kappa B super-repressor plasmid (an inhibitor of NF-kappa B activation) also prevented HIF-1 alpha induction by TNF-alpha. Surprisingly, although HIF-1 alpha mRNA levels remained unchanged after induction by TNF, induction of HIF-1 alpha protein by the cytokine was completely blocked by pretreatment with the transcription inhibitors actinomycin D and 5,6-dichlorobenzimidazole riboside. Finally, TNF failed to induce both HIF-1 alpha, made resistant to von Hippel-Lindau (VHL), and wild-type HIF-1 alpha transfected into VHL(-/-) cells. These results indicate that HIF-1 alpha induction by TNF-alpha in normoxic cells is mediated by protein stabilization but is nonetheless uniquely dependent on NF-kappa B-driven transcription. Thus the results describe a novel mechanism of HIF-1 alpha up-regulation and they identify HIF-1 alpha as a unique component of the NF-kappa B-mediated inflammatory/survival response.
authors.affiliation: Cell and Cancer Biology Branch, CCR, NCI, 9610 Medical Center Drive, Suite 300, Rockville, MD 20850, USA.
authors.forename: YunJin
authors.initials: Y
authors.lastname: Jung
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Isaacs
authors.forename: Sunmin
authors.initials: S
authors.lastname: Lee
authors.forename: Jane
authors.initials: J
authors.lastname: Trepel
authors.forename: Zheng-Gang
authors.initials: ZG
authors.lastname: Liu
authors.forename: Len
authors.initials: L
authors.lastname: Neckers
mesh_terms: D000818:Animals; D002460:Cell Line; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D017930:Genes, Reporter; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008025:Ligases / Q000378:metabolism; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016328:NF-kappa B; D011506:Proteins; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D017346:Protein Serine-Threonine Kinases; C506249:RIPK1 protein, human; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C506251:Ripk1 protein, mouse; D008025:Ligases; C497446:VHL protein, human; D010100:Oxygen