title: [Down-regulation of mTOR activity and survivin expression during tamoxifen-induced apoptosis in hepatoblastoma cells].
abstract: OBJECTIVE
  The aim of this study was to investigate the changes in mTOR activity and survivin expression in liver cancer cell line HepG2 cells treated with tamoxifen.
  
  
  METHODS
  Survivin transcription level and p70S6K was demonstrated by PCR, dual-luciferase reporter assay and Western blot analysis, respectively, and the apoptosis in the HepG2 cells was detected by flow cytometry.
  
  
  RESULTS
  Tamoxifen leads to apoptosis of the cells and reduction in survivin expression, as well as a dramatic reduction in the activated form of p70S6K. Treating HepG2 cells with rapamycin, a specific mTOR inhibitor, significantly reduced the survivin protein level but not affected the survivin transcription, indicating that tamoxifen and rapamycin were synergistic in regards to down-regulation of survivin expression in hepatocellular carcinoma cells.
  
  
  CONCLUSIONS
  Our results suggest that tamoxifen down-regulates survivin expression in HepG2 cells and it is mediated by transcriptional and post-transcriptional level via PI3K/Akt/mTOR pathway to induce apoptosis.
authors.affiliation: Department of Oncology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
authors.forename: Ren-Hua
authors.initials: RH
authors.lastname: Guo
authors.forename: Tong-Shan
authors.initials: TS
authors.lastname: Wang
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Chen
authors.forename: Zu-Hu
authors.initials: ZH
authors.lastname: Huang
authors.forename: Yong-Qian
authors.initials: YQ
authors.lastname: Shu
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation; D004357:Drug Synergism; D056945:Hep G2 Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology*; D000077022:Survivin; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013629:Tamoxifen / Q000494:pharmacology*
chemical_list: D000903:Antibiotics, Antineoplastic; D018931:Antineoplastic Agents, Hormonal; D051034:Inhibitor of Apoptosis Proteins; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D020123:Sirolimus; D000077022:Survivin; D058570:TOR Serine-Threonine Kinases; D013629:Tamoxifen; C107489:BIRC5 protein, human; C546842:MTOR protein, human