MicroRNA-129-2对人鼻咽癌CNE1细胞裸鼠移植瘤的抑制及其可能的机制

Inhibitory effect of microRNA-129-2 on xenografted human nasopharyngeal carcinoma development and its possible mechanism

目的:探讨microRNA-129-2(miR-129-2)对人鼻咽癌CNE1细胞裸鼠移植瘤生长的抑制作用及其可能的机制。方法:建立人鼻咽癌CNE1细胞裸鼠皮下移植瘤模型,按皮下注射的药剂将32只模型小鼠用随机数字表法分为4组:对照组(皮下注射生理盐水0.2 ml/d)、空白质粒组[(50μg/只,0.2 ml/次,1次/d]、顺铂(cisplatin,DDP)阳性对照组(1 mg/kg,0.2ml/次,1次/d)、miR-129-2组[(50μg/只,0.2 ml/次,1次/d],共治疗5周,记录裸鼠体质量、肿瘤体积、肿瘤质量。流式细胞术检测各组移植瘤组织S+G2-M期细胞比例,免疫组化和Western blotting方法检测miR-129-2对移植瘤组织中转录因子SOX4表达的影响。结果:成功建立CNE1细胞裸鼠皮下移植瘤模型,治疗第22天起,miR-129-2组移植瘤的体积和质量均显著低于对照组和空白质粒组(P<0.01),而与DDP组始终无明显差异(P>0.05);5周后,miR-129-2组荷瘤小鼠的体质量显著高于其他3组(均P<0.01)。miR-129-2组移植瘤组织S+G2-M期细胞比例显著低于与对照组和空白质粒组(P<0.01),与DDP组无显著差异(P>0.05)。移植瘤组织SOX4表达显著高于瘤旁组织,miR-129-2组和DDP组移植瘤组织内SOX4蛋白表达均较对照组显著降低(均P<0.01),且miR-129-2组SOX4蛋白表达显著低于DDP组(P<0.05)。结论:miR-129-2对人鼻咽癌CNE1细胞裸鼠皮下裸移植瘤的生长有明显的抑制作用,其机制可能与SOX4表达下调有关。

Objective： To investigate the inhibitory effect of microRNA-129-2（ miR-129-2） on xenografted human nasopharyngeal carcinoma development and SRY-related HMG-box transcription factor（ SOX4） expression in nude mice.Methods： Nude mice were injected with human nasopharyngeal carcinoma CNE1 cells. Animals with confirmed tumor lesions were randomized into 4 treatment groups（ n = 8） ： saline control（ subcutaneous injection of saline 0. 2 ml /d）,blank plasmid control（ 50 μg each mice in 0. 2 ml daily）,cisplatin（ DDP）（ 1 mg /kg in 0. 2 ml daily） and miR-129-2（ 50μg each mice in 0. 2 ml daily）. At 5 weeks after treatment,body weight and tumor volume and weight were measured,the proportion of cells at S /G2-M arrest in xenografted tumor cells was assessed by flow cytometry,and SOX4 protein content in xenograft tumors was assessed by immunohistochemical analysis and Western blotting. Results： In nude mice that developed nasopharyngeal carcinoma lesions after grafting of CNE1 cells,miR-129-2 led a significant decrease,comparable to that resulted from DDP treatment,in tumor volume and weight（ P 0. 01） whereas the control plasmid showed no effect（ P 0. 05）,as compared with the non-treatment control 22 days after treatment. Mice in the miR-129-2 group were significantly heavier than all other three groups of animals（ P 0. 01）. The proportion of cells at S /G2-M arrest was（ 37. 95± 1. 51） % in the non-treatment group,which was not different from the control plasmid group（ 36. 75 ± 1. 48） % but significantly decreased（ P 0. 01） in the miR-129-2 group（ 31. 81 ± 1. 45） % and the DDP treatment group（ 32. 34 ± 1.67） %. SOX4 protein content was significantly higher in tumors than in peritumoral tissues（ P 0. 05）. Both miR-129-2and DDP significantly lowered SOX4 protein content in tumors（ P 0. 01）,but the effect of miR-129-2 was more pronounced. Conclusion： The small non-coding RNA molecule miR-129-2 is capable of suppressing the growth of xenografted human nasopharyngeal carcinoma through down-regulation of SOX4 expression in nude mice,thus possessing a therapeutic potential for nasopharyngeal carcinoma.