title: Down-regulation of CITED2 attenuates breast tumor growth, vessel formation and TGF-β-induced expression of VEGFA.
abstract: While we previously demonstrated that CITED2 expression in primary breast tumor tissues is elevated relative to normal mammary epithelium and inversely correlated with patient survival, its functional impact on primary tumor development and progression remained unknown. To address this issue, we examined the effect of CITED2 silencing on the growth of human breast cancer cell lines MDA-MB-231 and MDA-MB-468 following orthotopic administration in vivo. Here, we show that CITED2 silencing significantly attenuated MDA-MB-231 primary tumor growth concordant with reduced tumor vascularization, while MDA-MB-468 primary tumor growth and tumor vascularization remained unaffected. Correspondingly, expression of VEGFA was significantly reduced in shCITED2-expressing MDA-MB-231, but not MDA-MB-468 tumors. Consistent with the observed pattern of vascularization and VEGFA expression, we found that TGF-β stimulation induced expression of VEGFA and enhanced CITED2 recruitment to the VEGFA promoter in MDA-MA-231 cells, while failing to induce VEGFA expression in MDA-MB-468 cells. Further supporting its involvement in TGF-β-induced expression of VEGFA, CITED2 silencing prevented TGF-β induction of VEGFA expression in MDA-MB-231 cells. Collectively, these data indicate that CITED2 regulates primary breast tumor growth, likely by influencing tumor vasculature via TGF-β-dependent regulation of VEGFA.
authors.affiliation: Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Swaathi
authors.initials: S
authors.lastname: Jayaraman
authors.affiliation: Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Doucet
authors.affiliation: Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Scott L
authors.initials: SL
authors.lastname: Kominsky
mesh_terms: D000818:Animals; D001665:Binding Sites; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008819:Mice, Nude; D009389:Neovascularization, Pathologic; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D047368:Tumor Burden; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: C486381:CITED2 protein, human; D012097:Repressor Proteins; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A
keywords: CITED2; TGF-β; VEGFA isoforms; primary tumor growth; vasculature