title: Mdm2 and HIF-1alpha interaction in tumor cells during hypoxia.
abstract: The interaction between HIF-1alpha, Mdm2, and p53 proteins during hypoxia has received recent attention. Here, we investigated the consequences of interaction between HIF-1alpha and Mdm2 under hypoxic conditions. Endogenous HIF-1alpha and Mdm2 proteins were co-immunoprecipitated from lysates of hypoxic HCT116 p53WT and p53(-/-) cells, suggesting that association of these two proteins is a p53-independent event. The cellular Mdm2 protein content was not significantly altered in hypoxic tumor cells. Overexpression of Mdm2 resulted in an increase in HIF-1alpha protein content in hypoxic cells and increased hypoxia-induced vascular endothelial growth factor (VEGF) transcriptional activation. These results point toward a novel and p53-independent function of Mdm2 to promote tumor cell adaptations to hypoxia by interacting with and promoting HIF-1 activation.
authors.affiliation: Department of Anatomy and Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Anna-Liisa
authors.initials: AL
authors.lastname: Nieminen
authors.forename: Suparna
authors.initials: S
authors.lastname: Qanungo
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Schneider
authors.forename: Bing-Hua
authors.initials: BH
authors.lastname: Jiang
authors.forename: Faton H
authors.initials: FH
authors.lastname: Agani
mesh_terms: D000818:Animals; D015687:Cell Hypoxia / Q000235:genetics; D002478:Cells, Cultured; D004347:Drug Interactions; D006801:Humans; D000860:Hypoxia / Q000235:genetics / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D051379:Mice; D009369:Neoplasms / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2