端粒酶卡侯体蛋白1干扰慢病毒对口腔鳞状细胞癌细胞裸鼠致瘤作用的研究

目的：探测端粒酶卡侯体蛋白1（TCAB1）基因沉默对裸鼠移植瘤生长及肿瘤细胞生物学行为的影响。方法采用定量荧光原位杂交（Q-FISH）方法测定RNA干扰慢病毒shTCAB1和sh阴性对照（NC）处理后经稳定筛选26代人口腔鳞状细胞癌（OSCC）的Cal27细胞系染色体末端端粒的信号强度。然后将RNA干扰的Cal27细胞接种于裸鼠颈部皮下左、右两侧，定期监测肿瘤体积，绘制肿瘤生长曲线，称取瘤体重量。采用免疫组织化学检测移植瘤组织中TCAB1、B细胞淋巴瘤蛋白-2（Bcl-2）、半胱氨酸天冬氨酸特异性蛋白酶-3、血管内皮生长因子（VEGF）和细胞周期蛋白D1的表达。结果 Q-FISH结果显示，shTCAB1处理后的Cal27细胞较shNC处理后及野生型Cal27细胞的端粒平均长度明显缩短。shTCAB1处理组OSCC移植瘤生长速度明显较shNC对照组减慢。移植瘤平均重量为0.06 g，对照组为0.26 g，抑瘤率达76.9%。免疫组织化学结果显示，shTCAB1组移植瘤中TCAB1表达明显降低，同时，Bcl-2、VEGF和细胞周期蛋白D1的表达降低，半胱氨酸天冬氨酸蛋白酶-3的表达升高。结论shTCAB1慢病毒能够明显抑制裸鼠人OSCC移植瘤的生长，其抗肿瘤机制与诱导肿瘤细胞凋亡、延长肿瘤细胞分裂周期及抑制血管生成有关。

Study on the antitumor effect of telomerase Cajal body protein 1-shRNA on human oral squamous cell carcinoma in nude mice

Objective To investigate the effects of silencing telomerase Cajal body protein 1(TCAB1) on the growth of a xenograft tumor and its biological behavior. Methods Quantitative fluorescence in situ hybridization(Q-FISH) was used to detect the fluorescence intensity of the telomere in oral squamous cell carcinoma(OSCC) Cal27 cells screened stably to the 26th passage with the treatment of shTCAB1 and sh negative control(NC). The results were then compared with wild-type Cal27 cells. Then these cells with RNA interference were inoculated subcutaneously into the left and right neck of the nude mice. Tumor volume was detected periodically to draw growth curves. The weight of the tumor was calculated after executing the nude mice. The expressions of TCAB1, Bcl-2, Caspase-3, vascular endothelial growth factor(VEGF), and Cyclin D1 in the xenograft tumor tissue were examined by immunohistochemistry. Results The results of Q-FISH showed that the telomere length was significantly shorter in shTCAB1 Cal27 cells than in the shNC and wild-type Cal27 cells. The xenograft tumor in the shTCAB1 treatment group had a slower growth rate than that in the shNC group. The average weight of tumors in two groups showed that the inhibition rate was 76.9%. The immunohistochemistry results demonstrated a lower expression of TCAB1 in the shTCAB1 group. Furthermore, down-regulated expression of Bcl-2, VEGF, and Cyclin D1 and up-regulated expre-ssion of Caspase-3 were observed compared with shNC group. Conclusion Depletion of TCAB1 using the shRNA lentivirus inhibited the proliferation of the xenograft tumor in vitro. The antitumor mechanism may be associated with the apoptosis-inducing extension of cell division cycle and angiogenesis inhibition.