EGCG对鼻咽癌CNE-2裸鼠移植瘤放疗的增敏作用及机制

目的探讨表没食子儿茶素没食子酸酯（EGCG）对鼻咽癌裸鼠移植瘤放疗的增敏作用及可能机制。方法将低分化鼻咽癌CNE-2细胞株接种于20只4～6周龄雄性BALA/C裸鼠皮下,肿瘤长至4～6mm时随机分为对照组、EGCG组、放疗组、EGCG＋放疗组。分别采用生理盐水、EGCG、放疗、EGCG＋放疗等干预。21天取出肿瘤,计算肿瘤抑制率;HE染色观察肿瘤细胞形态变化;RT-PCR检测瘤组织Caspase-3mRNA表达。结果与对照组相比,其他三组肿瘤抑制率均明显升高,EGCG＋放疗组显著高于EGCG组及放疗组（P〈0.05）;对照组肿瘤细胞生长旺盛,EGCG组、放疗组、EGCG＋放疗组可见大量凋亡及坏死细胞,其中以EGCG联合放疗组最明显。Caspase-3mRNA表达均明显升高,而以EGCG＋放疗组最为明显（P〈0.05）。结论 EGCG能增强鼻咽癌CNE-2裸鼠移植瘤对放疗的敏感性,其机制可能与上调Caspase-3mRNA的表达有关。

Sensitization and mechanisms of EGCG on radiotherapy of nasopharyngeal carcinoma xenotransplanted tumor in nude mice

Objective To explore the sensitization and possible mechanisms of Epigallocatechin-3-Gallate （ EGCG） on radiotherapy of nasopharyngeal carcinoma xenotransplanted tumor in nude mice. Methods Human nasopharyngeal carcinoma CNE-2 were inculated into 4-6 week-old male BALA/C nude mice,then were divided into control group ,EGCG group ,radiotherapy group,EGCG ＋ radiotherapy group when the tumor grew to the size of 4-6 mm,and administered respectively by saline,EGCG,radiotherapy,EGCG ＋ radiotherapy. All mice were killed after 21 days,and tumors were obtained to calculate tumor inhibition ratio; HE staining was used to observe the morphological changes ; and RT-PCR was applied to detect the expression of Caspase-3 mRNA in xenografts. Results Compared with the control group,the tumor inhibition ratio of the other three groups increased significantly,and which of the EGCG ＋ radiotherapy group were significantly higher than that of the EGCG group and radiotherapy group（ P 0. 05） ; tumor cells in the control group grew vigorously,and lots of apoptosis and necrosis cells were observed in the other three groups,especially in EGCG ＋ radiotherapy group. Compared with the control group,the expression of Caspase-3 mRNA in the other three groups increased,especially in EGCG ＋ radiotherapy group （ P 0. 05） . Conclusions EGCG can enhance the sensitivity of radiotherapy to the nasopharyngeal carcinoma CNE-2 xenografts in nude mice and its mechanisms may be related to the increase of Caspase-3 mRNA expression.