Removal of BRCA1/CtIP/ZBRK1 repressor complex on ANG1 promoter leads to accelerated mammary tumor growth contributed by prominent vasculature.
BRCA1 exerts transcriptional repression through interaction with CtIP in the C-terminal BRCT domain and ZBRK1 in the central domain. A dozen genes, including angiopoietin-1 (ANG1), a secreted angiogenic factor, are corepressed by BRCA1 and CtIP based on microarray analysis of mammary epithelial cells in 3D culture. BRCA1, CtIP, and ZBRK1 form a complex that coordinately represses ANG1 expression via a ZBRK1 recognition site in the ANG1 promoter. Impairment of this complex upregulates ANG1, which stabilizes endothelial cells that form a capillary-like network structure. Consistently, Brca1-deficient mouse mammary tumors exhibit accelerated growth, pronounced vascularization, and overexpressed ANG1. These results suggest that, besides its role in maintaining genomic stability, BRCA1 directly regulates the expression of angiogenic factors to modulate the tumor microenvironment.
Furuta
Saori
S
Department of Biological Chemistry, College of Medicine, University of California, Irvine, California 92697, USA.
Wang
Ju-Ming
JM
Wei
Shuanzeng
S
Jeng
Yung-Ming
YM
Jiang
Xianzhi
X
Gu
Bingnan
B
Chen
Phang-Lang
PL
Lee
Eva Y-H P
EY
Lee
Wen-Hwa
WH
D042683:Angiopoietin-1 / Q000235:genetics*; D000818:Animals; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004706:Endodeoxyribonucleases; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009389:Neovascularization, Pathologic / Q000473:pathology; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D034622:RNA Interference; D012097:Repressor Proteins / Q000378:metabolism*; D020218:Response Elements / Q000235:genetics
C467630:ANGPT1 protein, human; D042683:Angiopoietin-1; D019313:BRCA1 Protein; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; C422407:ZNF350 protein, human; D004706:Endodeoxyribonucleases; C410741:RBBP8 protein, human