title: [Effects of DAPT on proliferation of human dental pulp cells and Notch signaling pathway].
abstract: OBJECTIVE
  To explore whether the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT) could inhibit Notch signaling pathway in human dental pulp cells, and its effects on the proliferation ability of the cells.
  
  
  METHODS
  Human dental pulp cells were primarily cultured from healthy premolars or wisdom teeth extracted intactly. The γ-secretase inhibitor DAPT (5 μmol/L) was added to the culture medium from passage 4 to the end. The cells of passages 4, 8 and 10 were used as check points in this study. The Real-time RT-PCR and RT2 Profiler PCR Array were applied to analyze the expression changes of Notch signaling pathway downstream genes. And the methyl thiazolyl tetrazolium (MTT) method was used to test the proliferation ability of the cells.
  
  
  RESULTS
  After DAPT was added, Hes1 gene expression level decreased significantly in the cells of passages 4, 8 and 10 as compared with that of the same passage cells in the control group. The relative gene expression ratio (experimental/control) decreased to 0.20 in the cells of passage 10, and the difference was significant (t=33.143,P=0.001). The PCR Array results of passage 10 dental pulp cells also showed a decline of Notch signaling pathway downstream genes Hey1 and NR4A2 in the experimental group as compared with the control group. The proliferation of passages 8, and 10 experimental cells were slowed down, and the difference was significant.
  
  
  CONCLUSIONS
  Notch signaling pathway of human dental pulp cells could be inhibited by DAPT effectively. The proliferation of the cells was slowed down by the effect of DAPT, and the normal life cycle of the cells was affected.
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Xiao-ying
authors.initials: XY
authors.lastname: Zou
authors.forename: Heng
authors.initials: H
authors.lastname: Zhuang
authors.forename: Lin
authors.initials: L
authors.lastname: Yue
authors.forename: Xue-jun
authors.initials: XJ
authors.lastname: Gao
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors*; D049109:Cell Proliferation / Q000187:drug effects*; D003782:Dental Pulp / Q000166:cytology* / Q000187:drug effects; D004151:Dipeptides / Q000494:pharmacology*; D006801:Humans; D061251:Primary Cell Culture; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D004151:Dipeptides; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester; D051880:Receptors, Notch; D053829:Amyloid Precursor Protein Secretases