title: Int6/eIF3e silenced HIF2α stabilization enhances migration and tube formation of HUVECs via IL-6 and IL-8 signaling.
abstract: We previously identified the tumor suppressor INT6/eIF3e as a novel down regulator of HIF2α. Small interfering RNA targeting Int6 (siRNA-Int6) in HeLa cells led to normoxic stabilization of HIF2α, with concomitant transcription of angiogenic factors, including angiopoietin, basic fibroblast growth factor, and vascular endothelial growth factor. Here we used HIF2α normoxic up-regulation via Int6 silencing to investigate the role of HIF2α in endothelial cells. As a result Int6 silencing in human umbilical vein endothelial cells (HUVECs) and in human aortic endothelial cells (HAECs) led to robust enhanced cord formation and the medium supernatant of Int6 silenced HUVECs enhanced migration of untreated HUVECs, indicating a HIF2α triggered secretory signaling. Within the responsible genes were the cytokines interleukin-6 (IL-6) and IL-8 and not unlike in HeLa cells vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and epidermal growth factor (EGF). In addition application of IL-6 and IL-8 antibodies to the medium of Int6 silenced HUVECs could reverse the enhanced migration effect and also abrogated their tube formation. Finally, a CHIP assay analysis confirmed hypoxia-responsive elements (HREs) in the IL-6 and IL-8 promoters. Our results demonstrate that expression of both IL-6 and IL-8 is regulated by HIF2α and we suggest that IL-6 and IL-8 are HIF2α controlled cytokines for angiogenesis particularly in endothelial cells.
authors.affiliation: Department of Regenerative Medicine, and Stem Cell Research Center, Tongji University School of Medicine, 1239 Siping Road, Shanghai 200092, China. alexanderendler@msn.com
authors.forename: Alexander
authors.initials: A
authors.lastname: Endler
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Uchida
authors.forename: Takuya
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Lixia
authors.initials: L
authors.lastname: Lu
authors.forename: Guo-Tong
authors.initials: GT
authors.lastname: Xu
authors.forename: Futoshi
authors.initials: F
authors.lastname: Shibasaki
mesh_terms: D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D004247:DNA / Q000378:metabolism; D039621:Eukaryotic Initiation Factor-3 / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000235:genetics; D010100:Oxygen / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D055550:Protein Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D039621:Eukaryotic Initiation Factor-3; D015850:Interleukin-6; D016209:Interleukin-8; D010100:Oxygen; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D000099162:Endothelial PAS Domain-Containing Protein 1; C508606:CXCL8 protein, human; C508600:IL6 protein, human