title: Transcriptional repression of VEGF by ZNF24: mechanistic studies and vascular consequences in vivo.
abstract: VEGF is a key regulator of normal and pathologic angiogenesis. Although many trans-activating factors of VEGF have been described, the transcriptional repression of VEGF remains much less understood. We have previously reported the identification of a SCAN domain-containing C2H2 zinc finger protein, ZNF24, that represses the transcription of VEGF. In the present study, we identify the mechanism by which ZNF24 represses VEGF transcription. Using reporter gene and electrophoretic mobility shift assays, we identify an 11-bp fragment of the proximal VEGF promoter as the ZNF24-binding site that is essential for ZNF24-mediated repression. We demonstrate in 2 in vivo models the potent inhibitory effect of ZNF24 on the vasculature. Expression of human ZNF24 induced in vivo vascular defects consistent with those induced by VEGF knockdown using a transgenic zebrafish model. These defects could be rescued by VEGF overexpression. Overexpression of ZNF24 in human breast cancer cells also inhibited tumor angiogenesis in an in vivo tumor model. Analyses of human breast cancer tissues showed that ZNF24 and VEGF levels were inversely correlated in malignant compared with normal tissues. These data demonstrate that ZNF24 represses VEGF transcription through direct binding to an 11-bp fragment of the VEGF proximal promoter and that it functions as a negative regulator of tumor growth by inhibiting angiogenesis.
authors.affiliation: Vascular Biology Program and Department of Surgery, Children's Hospital Boston, Boston, MA 02115, USA.
authors.forename: Di
authors.initials: D
authors.lastname: Jia
authors.forename: Sean M
authors.initials: SM
authors.lastname: Hasso
authors.forename: Joanne
authors.initials: J
authors.lastname: Chan
authors.forename: Domenic
authors.initials: D
authors.lastname: Filingeri
authors.forename: Patricia A
authors.initials: PA
authors.lastname: D'Amore
authors.forename: Lori
authors.initials: L
authors.lastname: Rice
authors.forename: Christine
authors.initials: C
authors.lastname: Pampo
authors.forename: Dietmar W
authors.initials: DW
authors.lastname: Siemann
authors.forename: David
authors.initials: D
authors.lastname: Zurakowski
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Rodig
authors.forename: Marsha A
authors.initials: MA
authors.lastname: Moses
mesh_terms: D000818:Animals; D001665:Binding Sites; D001808:Blood Vessels / Q000378:metabolism*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism; D015027:Zebrafish
chemical_list: D051741:Kruppel-Like Transcription Factors; D012097:Repressor Proteins; D042461:Vascular Endothelial Growth Factor A; C457300:ZNF24 protein, human