title: The angiogenesis suppressor gene AKAP12 is under the epigenetic control of HDAC7 in endothelial cells.
abstract: Histone deacetylases (HDACs) are a family of 18 enzymes that deacetylate lysine residues of both histone and nonhistone proteins and to a large extent govern the process of angiogenesis. Previous studies have shown that specific inhibition of HDAC7 blocks angiogenesis both in vitro and in vivo. However, the underlying molecular mechanisms are not fully understood and hence preclude any meaningful development of suitable therapeutic modalities. The goal of the present study was to further the understanding of HDAC7 epigenetic control of angiogenesis in human endothelial cells using the proteomic approach. The underlying problem was approached through siRNA-mediated gene-expression silencing of HDAC7 in human umbilical vein endothelial cells (HUVECs). To this end, HUVEC proteins were extracted and proteomically analyzed. The emphasis was placed on up-regulated proteins, as these may represent potential direct epigenetic targets of HDAC7. Among several proteins, A-kinase anchor protein 12 (AKAP12) was the most reproducibly up-regulated protein following HDAC7 depletion. This overexpression of AKAP12 was responsible for the inhibition of migration and tube formation in HDAC7-depleted HUVEC. Mechanistically, H3 histones associated with AKAP12 promoter were acetylated following the removal of HDAC7, leading to an increase in its mRNA and protein levels. AKAP12 is responsible for protein kinase C mediated phosphorylation of signal transducer and activator of transcription 3 (STAT3). Phosphorylated STAT3 increasingly binds to the chromatin and AKAP12 promoter and is necessary for maintaining the elevated levels of AKAP12 following HDAC7 knockdown. We demonstrated for the first time that AKAP12 tumor/angiogenesis suppressor gene is an epigenetic target of HDAC7, whose elevated levels lead to a negative regulation of HUVEC migration and inhibit formation of tube-like structures.
authors.affiliation: Metastasis Research Laboratory, GIGA-Cancer, University Hospital, University of Liège, Bat. B23, CHU Sart Tilman, 4000, Liège, Belgium. a.turtoi@ulg.ac.be
authors.forename: Andrei
authors.initials: A
authors.lastname: Turtoi
authors.forename: Denis
authors.initials: D
authors.lastname: Mottet
authors.forename: Nicolas
authors.initials: N
authors.lastname: Matheus
authors.forename: Bruno
authors.initials: B
authors.lastname: Dumont
authors.forename: Paul
authors.initials: P
authors.lastname: Peixoto
authors.forename: Vincent
authors.initials: V
authors.lastname: Hennequière
authors.forename: Christophe
authors.initials: C
authors.lastname: Deroanne
authors.forename: Alain
authors.initials: A
authors.lastname: Colige
authors.forename: Edwin
authors.initials: E
authors.lastname: De Pauw
authors.forename: Akeila
authors.initials: A
authors.lastname: Bellahcène
authors.forename: Vincent
authors.initials: V
authors.lastname: Castronovo
mesh_terms: D054758:A Kinase Anchor Proteins / Q000235:genetics*; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics*; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D044127:Epigenesis, Genetic; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000502:physiology; D018919:Neovascularization, Physiologic / Q000235:genetics*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000378:metabolism; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor / Q000378:metabolism
chemical_list: D054758:A Kinase Anchor Proteins; C491162:AKAP12 protein, human; D018797:Cell Cycle Proteins; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D018799:Intercellular Adhesion Molecule-1; D011493:Protein Kinase C; C543273:HDAC7 protein, human; D006655:Histone Deacetylases