title: [Effects of radiosensitivity and X-ray dose on miR-7 expression in nasopharyngeal carcinoma].
abstract: OBJECTIVE
  To investigate the effects of radiosensitivity and X-ray dose on the expression of miR-7 in nasopharyngeal carcinoma (NPC) cells.
  
  
  METHODS
  Low radiosensitive NPC cells CNE-1 and high radiosensitive NPC cells CNE-2 were exposed to 0, 2 and 8 Gy X-ray. The total RNAs of the cell lines were extracted 10 h after radiation for reverse transcription of miR-7 and 18S rRNA by stem-loop primer and random hexamers, respectively. The non-irradiated CNE-1 cells served as the control sample and the relative quantity of the expression level was calculated after real-time PCR using SyBR green.
  
  
  RESULTS
  miR-7 expression differed significantly between CNE-1 and CNE-2 cells (4.49-/+3.62 vs 1.29-/+1.10, F=135.483, P<0.001). The radiation dose also significantly affected the expression of miR-7 in NPC cells (F=39.565, P<0.001). CNE-1 cells with a 2 Gy exposure had the highest expression level of miR-7, while the non-irradiated CNE-1 cells had the lowest expression. CNE-2 cells exposed to 2 Gy X-ray had the lowest expression level of miR-7 and the non-irradiated CNE-2 cells had the highest.
  
  
  CONCLUSIONS
  Radiosensitivity and radiation dose of X-ray have significant effect on the expression of miR-7 in NPC cells, indicating that miR-7 plays an important role in radioresistance of NPC cells to X-ray, and suppressed miR-7 expression may elevate the radiosensitivity of NPC cells.
authors.affiliation: Department of Radiotherapy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. flashido@yahoo.com.cn
authors.forename: Zhi-xian
authors.initials: ZX
authors.lastname: Chen
authors.forename: Ai-min
authors.initials: AM
authors.lastname: Sun
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Jun-fang
authors.initials: JF
authors.lastname: Zhan
authors.forename: Long-hua
authors.initials: LH
authors.lastname: Chen
authors.forename: Ya-wei
authors.initials: YW
authors.lastname: Yuan
mesh_terms: D017209:Apoptosis / Q000528:radiation effects; D002277:Carcinoma; D045744:Cell Line, Tumor; D004307:Dose-Response Relationship, Radiation; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics*; D011836:Radiation Tolerance / Q000235:genetics*; D014965:X-Rays
chemical_list: D035683:MicroRNAs; C549242:MIRN7-1 microRNA, human