title: The effects of dexamethasone on the proliferation and apoptosis of human ovarian cancer cells induced by paclitaxel.
abstract: BACKGROUND
  Dexamethasone (DEX) has been routinely used as a pre-treatment in the clinical application of paclitaxel (PTX) to treat ovarian cancer. However, PTX-induced apoptosis might be inhibited by DEX. This study was undertaken to investigate the effects of DEX on the apoptosis induced by PTX.
  
  
  METHODS
  Both of SKOV-3 and HO-8910 human ovarian cancer cells were divided into four groups: (1) untreated (Con); (2) treated with DEX (0.1 μM) alone; (3) treated with PTX (50 nM); and (4) pre-treated with DEX (0.1 μM), and 24 h later, treated with PTX (DEX + PTX). Cell proliferation was determined by the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) dye uptake method, while cell apoptosis was analyzed by propidium iodide (PI) staining and flow cytometry. Then, reverse transcription polymerase chain reactions (RT-PCRs) were applied to semi-quantitative analysis, followed by western blot analysis. Statistical analysis was performed, with Fisher's least significant difference test.
  
  
  RESULTS
  Our results demonstrated that DEX can differentially inhibit SKOV-3 and HO-8910 cell proliferation induced by PTX and decrease the apoptosis rates in cancer cells. Pre-treatment with DEX could up-regulate the expressions of members of anti-apoptotic Bcl-2 family (Bcl-2 and Bcl-XL) and members of IAP family (survivin). The expression of cleaved caspase-3 was down-regulated by DEX, shown by semi-quantitative RT-PCRs and western blot analysis.
  
  
  CONCLUSIONS
  Our data gained invaluable insights of the antagonistic mechanisms of DEX on PTX-induced cancer cell death and may provide new methods of using DEX as antineoplastic drugs or agents in the clinical treatment for ovarian cancer patients.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Hou
authors.forename: Jianhua
authors.initials: J
authors.lastname: Guan
authors.forename: Huan
authors.initials: H
authors.lastname: Lu
authors.forename: Qian
authors.initials: Q
authors.lastname: Dong
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Han
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003907:Dexamethasone / Q000493:pharmacokinetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D000077022:Survivin; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D000077022:Survivin; D051020:bcl-X Protein; D003907:Dexamethasone; D053148:Caspase 3; D017239:Paclitaxel