| Objective:To investigate the effect and the potential mechanism of microRNA-24 (miR-24) in radiation sensitivity on xenografted human nasopharyngeal carcinoma. To explore the more potent and less toxic new functional molecule, which may enhance the radiation sensitivity in molecular genetics domain.Methods:Established the model of human nasopharyngeal carcinoma CNE2 cells xenografts in nude mice, all the nude mice were randomly divided into four groups after tumor formation. MiR-24 (10nmol each mice in 0.1ml every four days), miR-24 NC (10nmol each mice in 0.1ml every four days), cisplatin (DDP)(1mg/kg in 0.1ml every four days), saline control (subcutaneous injection of saline 0.1ml every four days), two times totally.8Gy of radiation was used after the second injection with cobalt-60 machine. The volume of tumor was measured every 2 days after radiation. All the mice were put to death at the 16th day after radiation. The expression of Spl mRNA in subcutaneous tumor was detected by Real-time PCR. The expression of Sp1 protein in subcutaneous tumor was detected by immunohistochemistry and Western blot.Results:The average rate of tumor growth in miR-24 agomir group was slower than the rate in miR-24 agomir NC group and NS group after radiation (P<0.05).The mean value of tumor volume of miR-24 agomir group was (748.9±61.9mm3), which was smaller than that in miR-24 agomir NC group(1961.2±126.8mm3) and NS group (2048.0± 101.8mm3) (P<0.05) compared with DDP group, the result indicated no statistical difference (P> 0.05). The mRNA and protein expression of Sp1 were decreased in miR-24 agomir group compared with that in miR-24 agomir NC group and NS group (P<0.05). However, the Sp1 mRNA and protein expression were higher in miR-24 agomir group compared with DDP group (P<0.05)Conclusions:The results indicate that miR-24 can enhance the radiation sensitivity of human nasopharyngeal carcinoma CNE2 cell xenografts in nude mice, and the mechanism may be related to the down-regulation of Spl. |
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