Vascular endothelial growth factor receptor-2 expression is induced by 17beta-estradiol in ZR-75 breast cancer cells by estrogen receptor alpha/Sp proteins.
Vascular endothelial growth factor receptor-2 kinase insert domain receptor (VEGFR2/KDR) is critical for angiogenesis, and VEGFR2 mRNA and protein are expressed in ZR-75 breast cancer cells and induced by 17beta-estradiol (E2). Deletion analysis of the VEGFR2 promoter indicates that the proximal GC-rich region is required for both basal and hormone-induced transactivation, and mutation of one or both of the GC-rich motifs at -58 and -44 results in loss of transactivation. Electrophoretic mobility shift and chromatin immunoprecipitation assays show that Sp1, Sp3, and Sp4 proteins bind the GC-rich region of the VEGFR2 promoter. Results of the chromatin immunoprecipitation assay also demonstrate that ERalpha is constitutively bound to the VEGFR2 promoter and that these interactions are not enhanced after treatment with E2, whereas ERalpha binding to the region of the pS2 promoter containing an estrogen-responsive element is enhanced by E2. RNA interference studies show that hormone-induced activation of the VEGFR2 promoter constructs requires Sp3 and Sp4 but not Sp1, demonstrating that hormonal activation of VEGFR2 involves a nonclassical mechanism in which ERalpha/Sp3 and ERalpha/Sp4 complexes activate GC-rich sites where Sp proteins but not ERalpha bind DNA. These results show for the first time that Sp3 and Sp4 cooperatively interact with ERalpha to activate VEGFR2 and are in contrast to previous results showing that several hormone-responsive genes are activated by ERalpha/Sp1 in breast cancer cell lines.
Department of Biochemistry, Texas A&M University, College Station, 77843-4466, USA.
Kelly J
KJ
Higgins
Shengxi
S
Liu
Maen
M
Abdelrahim
Kyungsil
K
Yoon
Kathryn
K
Vanderlaag
Weston
W
Porter
Richard P
RP
Metz
Stephen
S
Safe
D001483:Base Sequence; D001943:Breast Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism / Q000502:physiology*; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008969:Molecular Sequence Data; D009389:Neovascularization, Pathologic; D011401:Promoter Regions, Genetic; D051703:Sp Transcription Factors / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis*
D047628:Estrogen Receptor alpha; D051703:Sp Transcription Factors; D004958:Estradiol; D040301:Vascular Endothelial Growth Factor Receptor-2