title: [Influence of Delta-like ligand 4/Notch signal transduction pathway upon the biological behavior of human umbilical vein endothelial cells].
abstract: OBJECTIVE
  To study the influence of inhibiting Delta-like ligand 4 (Dll4)/Notch signal transduction pathway upon the biological behavior of human umbilical vein endothelial cells (HUVEC).
  
  
  METHODS
  Used rAAV vectors expressing an active small interfering RNA (siRNA) (vector 6) targeting the Dll4 (rAAV-Dll4-shRNA) to infect HUVEC. And an empty plasmid (rAAV-EGFP) was infected into the same cell line as control group. The stable transfection and expression of Dll4 mRNA in HUVEC were determined by semi-quantitative RT-PCR. The protein expression of Dll4 was examined by Western blotting. Distribution of cell cycle was assessed by flow cytometry. The cell growth was analyzed by MTT assay. HUVEC were separated by type I collagen and cultured in a three-dimensional culture system for tubule like structure (TLS) formation.
  
  
  RESULTS
  Compared with the negative control cells, semi-quantitative RT-PCR and Western blotting showed the expression of Dll4 mRNA (0.636 +/- 0.082, 0.972 +/- 0.022 vs 0.948 +/- 0.046) and protein (0.632 +/- 0.052, 2.016 +/- 0.048 vs 1.946 +/- 0.066) were down-regulated in the stable cell (P = 0.024, 0.033). The rAAV vectors expressing an active small interfering RNA (siRNA) targeting the Dll4 effectively stimulated HUVEC cell growth and proliferation while empty plasmid had no such specific effect. The proliferation index of experimental group was (39.9 +/- 2.2)% versus untreated group (25.7 +/- 4.5)% (P = 0.036). TLS formation was significantly induced by rAAV vector. And the average length of TLS were more than those of control group (12.5 +/- 0.5, 8.7 +/- 7.7, 8.5 +/- 3.0, P = 0.028).
  
  
  CONCLUSIONS
  The inhibiting Dll4/Notch signal transduction pathway stimulates the proliferation of HUVEC and facilitates the angiogenesis. Interference with Dll4/Notch signaling may be particularly desirable in tumors with highly induced Dll4/Notch pathway.
authors.affiliation: Department of General Surgery, General Hospital of Chinese PLA, Beijing 100853, China. chenlinbj@vip.sina.com
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Lü
authors.forename: Bo
authors.initials: B
authors.lastname: Wei
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Li
mesh_terms: D049109:Cell Proliferation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection; D014471:Umbilical Veins / Q000166:cytology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D034741:RNA, Small Interfering; D051880:Receptors, Notch; C064045:delta protein