title: [Expression of multidrug resistance gene in nasopharyngeal carcinoma cells after irradiation exposure].
abstract: OBJECTIVE
  To examine the changes in the function and expression of multidrug resistance gene (mdr1) and P-gly-coprotein (P-gp) in nasopharyngeal carcinoma (NPC) CNE1 cell following irradiation for determining the sequential order of radiotherapy and chemotherapy in the treatment of NPC.
  
  
  METHODS
  The expressions of mdr1 gene and its protein P-gp as well as the function of P-gp efflux were examined in CNE1 cells before and after irradiation exposure by reverse transcriptional polymerase chain reaction (RT-PCR), Western blotting and flow cytometry, respectively.
  
  
  RESULTS
  Irradiation of CNE1 cells induced a long-term overexpression of mdr1 gene and P-gp and reduction in intracellular daunorubicin accumulation.
  
  
  CONCLUSIONS
  Irradiation decreases the chemotherapy sensitivity of CNE1 cell, and induction chemotherapy should be therefore performed before radiotherapy in the treatment of advanced NPC.
authors.affiliation: Department of Radiotherapy, Oncology Center, Zhujiang Hospital, First Military Medical University, Guangzhou 510282, China.
authors.forename: Jun-guo
authors.initials: JG
authors.lastname: Bu
authors.forename: Ya-wei
authors.initials: YW
authors.lastname: Yuan
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
mesh_terms: D045744:Cell Line, Tumor; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D019450:Genes, MDR; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000532:radiotherapy*; D020133:Reverse Transcriptase Polymerase Chain Reaction