Browsing by Subject "Dll4"

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    Aberrant expression and association of VEGF and Dll4/Notch pathway molecules under hypoxia in patients with lung cancer
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2013) Yu, Shuang; Sun, Jianhua Sun; Zhang, Jingru; Xu, Xingfang; Li, Hong; Shan, Baozhong; Tian, Tian; Wang, Hongchun; Ma, Daoxin; Ji, Chunyan
    Tumor angiogenesis plays important roles in the pathogenesis and prognosis of lung cancer. Both vascular endothelial growth factor (VEGF) and Dll4/Notch pathways are critical for angiogenesis, whereas their relationship under hypoxia in lung cancer remains unknown. Thus, in the present study, we evaluated the expression of VEGF and Dll4/Notch signaling molecules, and assessed their association with the microvessel density (CD31) and hypoxia (HIF1a) in lung cancer and normal lung tissues using immunohistochemical and Real-time RT-PCR techniques. Then, we investigated the biological function of Dll4 by transfecting Dll4 into HUVECs. In lung cancer tissues, Notch pathway molecules (HES1) and VEGF pathway molecules (VEGFR1 and VEGFR2) were significantly up-regulated, while the ratio of VEGFR1/VEGFR2 was decreased. CD31 and HIF1a were also found to be elevated in lung cancer. VEGFR1 was negatively correlated with Notch1 while positively correlated with Dll4. CD31 was positively correlated with HIF1a but negatively correlated with VEGFR1. Moreover, HIF1a was nearly positively correlated with HES1 in lung cancer tissues. After transfection, Dll4, Notch1 and VEGFR1 were up-regulated while VEGF and VEGFR2 were down-regulated in Dll4-transfected HUVECs compared with controls. Also, our findings suggest that the expression of VEGF and VEGFR2 increased gradually with the disease progression of lung cancer. In summary, VEGF and Notch signaling pathway molecules were overexpressed in lung cancer, which positively correlates with hypoxia (HIF1a) and angiogenesis (CD31). There might be a negative feedback loop between VEGF and Dll4/Notch signaling pathway in lung tumor angiogenesis.
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    Analysis of Dll4 regulation reveals a combinatorial rolefor Sox and Notch in arterial development
    (National Academy of Sciences, 2013-07-01) Sacilotto, Natalia; Monteiro, Rui; Fritzsche, Martin; Becker, Philipp W.; Liu, Ke; Pinheiro, Philip; Ratnayakaa, Indrika; Davies, Benjamin; Goding, Colin R.; Patient, Roger; Bou Gharios, George; De Val, Sarah; Sánchez del Campo Ferrer, Luis; Bioquímica y Biología Molecular A
    The mechanisms by which arterial fate is established and main-tained are not clearly understood. Although a number of signalingpathways and transcriptional regulators have been implicated inarterio-venous differentiation, none are essential for arterialformation, and the manner in which widely expressed factorsmay achieve arterial-specific gene regulation is unclear. Using bothmouse and zebrafish models, we demonstrate here that arterialspecification is regulated combinatorially by Notch signaling andSoxF transcription factors, via direct transcriptional gene activa-tion. Through the identification and characterization of two arte-rial endothelial cell-specific gene enhancers for the Notch ligandDelta-like ligand 4 (Dll4), we show that arterial Dll4 expressionrequires the direct binding of both the RBPJ/Notch intracellulardomain and SOXF transcription factors. Specific combinatorial,but not individual, loss of SOXF and RBPJ DNA binding ablatesall Dll4 enhancer-transgene expression despite the presence ofmultiple functional ETS binding sites, as does knockdown of sox7;sox18 in combination with loss of Notch signaling. Furthermore,triple knockdown of sox7, sox18 and rbpj also results in ablationof endogenous dll4 expression. Fascinatingly, this combinatorialablation leads to a loss of arterial markers and the absence of a de-tectable dorsal aorta, demonstrating the essential roles of SoxF andNotch, together, in the acquisition of arterial identity