title: The effect of transforming growth factor-beta1 on nasopharyngeal carcinoma cells: insensitive to cell growth but functional to TGF-beta/Smad pathway.
abstract: OBJECTIVE
  This study explored the response of nasopharyngeal carcinoma cells to TGF-beta1-induced growth suppression and investigated the roles of the TGF-beta/Smad signaling pathway in nasopharyngeal carcinoma cells.
  
  
  METHODS
  The cells of nasopharyngeal carcinoma cell line CNE2 were treated with TGF-beta1. The growth responses of CNE2 cells were analyzed by MTT assay. The mRNA expression and protein subcellular localization of the TGF-beta/Smad signaling components in the CNE2 were determined by real time RT-PCR and immunocytochemical analysis.
  
  
  RESULTS
  We found that the growth of CNE2 cells was not suppressed by TGF-beta1. The signaling proteins TbetaRII, Smad 7 were expressed normally, while Smad2, Smad3, and Smad4 increased significantly at the mRNA level. TGF-beta type II receptor and Smad7 had no change compared to the normal nasopharyngeal epithelial cells. In addition, Smad2 was phosphorylated to pSmad2, and the activated pSmad2 translocated into the nucleus from the cytoplasm, while the inhibitory Smad-Smad7 translocated from the nucleus to the cytoplasm after TGF-beta1 stimulation.
  
  
  CONCLUSIONS
  The results suggested that CNE2 cells are not sensitive to growth suppression by TGF-beta1, but the TGF-beta/Smad signaling transduction is functional. Further work is needed to address a more detailed spectrum of the TGF-beta/Smad signaling pathway in CNE2 cells.
authors.affiliation: School of Pharmacy, Wenzhou Medical College, Wenzhou 325035, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xiao
authors.forename: Qi
authors.initials: Q
authors.lastname: Xiang
authors.forename: Ye-Chen
authors.initials: YC
authors.lastname: Xiao
authors.forename: Zhi-Jian
authors.initials: ZJ
authors.lastname: Su
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Huang
authors.forename: Qi-Hao
authors.initials: QH
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Tan
authors.forename: Xiao-Kun
authors.initials: XK
authors.lastname: Li
authors.forename: Ya-Dong
authors.initials: YD
authors.lastname: Huang
mesh_terms: D002277:Carcinoma / Q000378:metabolism*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism*; D013997:Time Factors; D053773:Transforming Growth Factor beta1 / Q000096:biosynthesis*
chemical_list: D051785:Smad Proteins; D053773:Transforming Growth Factor beta1