title: γ-secretase inhibitor DAPT sensitizes t-AUCB-induced apoptosis of human glioblastoma cells in vitro via blocking the p38 MAPK/MAPKAPK2/Hsp27 pathway.
abstract: OBJECTIVE
  Trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB) is a soluble epoxide hydrolase inhibitor that suppresses glioblastoma cell growth in vitro. The aim of this study was to examine whether the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT) could sensitize glioma cells to t-AUCB-induced apoptosis.
  
  
  METHODS
  Both U251 and U87 human glioblastoma cell lines were tested. Cell growth was assessed using the cell counting kit-8. Cell apoptosis was detected with caspase-3 activity assay kits and flow cytometry. The protein levels in the p38 MAPK/MAPKAPK2/Hsp27 pathway in the cells were analyzed using Western blots.
  
  
  RESULTS
  Pretreatment with DAPT (2 μmol/L) substantially potentiated the growth inhibition caused by t-AUCB (200 μmol/L) in U251 and U87 cells. Furthermore, pretreatment with DAPT markedly increased t-AUCB-induced apoptosis of U251 and U87 cells. T-AUCB alone did not significant affect caspase-3 activity in the cells, but t-AUCB plus DAPT pretreatment caused significant increase of caspase-3 activity. Furthermore, pretreatment with DAPT completely blocked t-AUCB-induced phosphorylation of p38 MAPK, MAPKAPK2 and Hsp27 in the cells.
  
  
  CONCLUSIONS
  The γ-secretase inhibitor DAPT sensitizes t-AUCB-induced apoptosis of human glioblastoma cells in vitro via blocking the p38 MAPK/MAPKAPK2/Hsp27 pathway, suggesting that the combination of t-AUCB and DAPT may be a potentially effective strategy for the treatment of glioblastoma.
authors.affiliation: Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China.
authors.forename: Jun-Yang
authors.initials: JY
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, Second Affiliated Hospital of Soochow University, Suzhou 215004, China.
authors.forename: Ru-Jun
authors.initials: RJ
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China.
authors.forename: Han-Dong
authors.initials: HD
authors.lastname: Wang
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors*; D017209:Apoptosis / Q000187:drug effects*; D001565:Benzoates / Q000378:metabolism*; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004151:Dipeptides / Q000494:pharmacology*; D005909:Glioblastoma / Q000188:drug therapy* / Q000378:metabolism; D055551:HSP27 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D014508:Urea / Q000031:analogs & derivatives* / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D053829:Amyloid Precursor Protein Secretases; D001565:Benzoates; D004151:Dipeptides; D055551:HSP27 Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; D017346:Protein Serine-Threonine Kinases; D014508:Urea; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2; C524106:4-(4-(3-adamantan-1-ylureido)cyclohexyloxy)benzoic acid; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester