Chen Zhi-xian, Sun Ai-min, Chen Yong, Liu Ying, Zhan Jun-fang, Chen Long-hua, Yuan Ya-wei
Department of Radiotherapy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2010 Aug;30(8):1810-2, 1816.
To investigate the effects of radiosensitivity and X-ray dose on the expression of miR-7 in nasopharyngeal carcinoma (NPC) cells.
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.
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.
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.
探讨放射敏感性和X射线剂量对鼻咽癌（NPC）细胞中miR-7表达的影响。
将低放射敏感性的NPC细胞CNE-1和高放射敏感性的NPC细胞CNE-2分别暴露于0、2和8 Gy的X射线下。照射后10小时提取细胞系的总RNA，分别用茎环引物和随机六聚体对miR-7和18S rRNA进行逆转录。未照射的CNE-1细胞作为对照样本，使用SyBR green进行实时PCR后计算表达水平的相对量。
CNE-1和CNE-2细胞中miR-7的表达存在显著差异（4.49±3.62对1.29±1.10，F = 135.483，P < 0.001）。辐射剂量也显著影响NPC细胞中miR-7的表达（F = 39.565，P < 0.001）。照射2 Gy的CNE-1细胞miR-7表达水平最高，而未照射的CNE-1细胞表达最低。照射2 Gy X射线的CNE-2细胞miR-7表达水平最低，未照射的CNE-2细胞表达最高。
X射线的放射敏感性和辐射剂量对NPC细胞中miR-7的表达有显著影响，表明miR-7在NPC细胞对X射线的放射抗性中起重要作用，抑制miR-7表达可能提高NPC细胞的放射敏感性。
