[Effects of radiosensitivity and X-ray dose on miR-7 expression in nasopharyngeal carcinoma].
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.
Chen
Zhi-xian
ZX
Department of Radiotherapy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. flashido@yahoo.com.cn
Sun
Ai-min
AM
Chen
Yong
Y
Liu
Ying
Y
Zhan
Jun-fang
JF
Chen
Long-hua
LH
Yuan
Ya-wei
YW
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
D035683:MicroRNAs; C549242:MIRN7-1 microRNA, human