title: [Inhibition of human lung fibroblast proliferation and the mitogen activated protein kinase pathway by dexamethasone].
abstract: OBJECTIVE
  To investigate the effects of dexamethasone on human lung fibroblast cell proliferation, cell cycles, and cell mitogen-activated protein kinases (MAPKs) passway.
  
  
  METHODS
  Dexamethasone was used at various concentration in culture medium. Cell number was counted using a hemacytometer. Whole cell propidium iodide staining and flow cytometric analysis were performed to determine cellular DNA content. MAPK proteins and activation were tested by Western blot analysis with antibodies to c-Jun N-terminal kinase (JNK), phospho-JNK, extracellular signal-regulated kinase (ERK), phospho-ERK, p38 and phospho-p38.
  
  
  RESULTS
  1x10(-7) mol/L and 1x10(-6) mol/L dexamethasone suppressed the proliferation of lung fibroblast cells by 34% and 72%, respectively, than that of control. This suppression was dose-dependant. Dexamethasone suppressed cell cycle with accumulation of cells in G1/G0 stage. It increased from 81.9% to 90.1% compared with that of control. We did not find any apoptosis induced by dexamethasone for lung fibroblast cells. Using Western blot analysis, we found that dexamethasone resulted in decreased activity of ERK, but had no effects on JNK and p38.
  
  
  CONCLUSIONS
  Dexamethasone may suppresses the proliferation of lung fibroblast cells, which is partly resulted from the facts that it can inhibit ERK activation in MAPK-signaling pathway but has little effect on JNK and p38 pathway. Dexamethasone may not induce lung fibroblast cell apoptosis directly.
authors.affiliation: Department of Respiratory Disease, PUMC Hospital, CAMS and PUMC, Beijing 100730, China. guozj@pumch.ac.cn
authors.forename: Zi-jian
authors.initials: ZJ
authors.lastname: Guo
authors.forename: Yuan-jue
authors.initials: YJ
authors.lastname: Zhu
authors.forename: Li
authors.initials: L
authors.lastname: Gu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.forename: Li-jun
authors.initials: LJ
authors.lastname: Li
authors.forename: Xin-lun
authors.initials: XL
authors.lastname: Tian
authors.forename: Wei
authors.initials: W
authors.lastname: Yao
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003864:Depression, Chemical; D003907:Dexamethasone / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology*; D006801:Humans; D008168:Lung / Q000166:cytology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020929:Mitogen-Activated Protein Kinase Kinases / Q000187:drug effects*
chemical_list: D003907:Dexamethasone; D020929:Mitogen-Activated Protein Kinase Kinases