表达端粒酶逆转录酶siRNA的溶瘤腺病毒对裸鼠肾癌移植瘤的治疗作用

The antitumor effects of oncolytic adenovirus armed with small interference RNA targeting hTERT gene for renal cancer therapy in nude mouse model

目的观察表达针对端粒酶逆转录酶（hTERT）基因的小干扰RNA（hTERTsiRNA）的溶瘤腺病毒（ZD55-hTERT）抑制肾癌移植瘤生长作用。方法荷肾癌裸鼠随机分4组，每组8只。瘤体内分别注射ZD55-hTERT、增殖缺陷型腺病毒（Ad—hTERT）、溶瘤腺病毒ZD55．EGFP及磷酸盐缓冲液（PBS），每次注射病毒7×10^8pfu／只，连续注射3d。注射后第7天，每组处死3只取肿瘤组织，免疫组织化学检测肿瘤hTERT、E1A表达及凋亡。第50天时处死动物测量肿瘤体积。结果ZD55-hTERT、Ad—hTERT、ZD55-EGFP及PBS处理组肿瘤体积（mm^3）分别为：124．1±27．5、609．0±102．5、499．8±77．1、1552．1±206．4，ZD55-hTERT处理组与各组之间差异有统计学意义（P〈0．01）。Ad—hTERT处理组肿瘤无EIA表达，ZD55-hTERT处理组E1A大量表达，表明病毒复制。ZD55-hTERT处理组肿瘤hTERT表达显著低于Ad—hTERT处理组，凋亡细胞阳性率均显著高于Ad—hTERT处理组。结论表达hTERTsiRNA的溶瘤腺病毒ZD55-hTERT具有更强的抑制肾癌生长作用。

Objective To investigate the antitumor effect of oncolytic adenovirus armed with small interference RNA targeting hTERT gene for renal cancer therapy. Methods Nude mice were divided randomly into 4 groups （ 8 mice/group）, and were treated by intratumoral injections of ZD55-hTERT （an oncolytic adenovirus armed with small interference RNA targeting hTERT gene） ,ZD55-EGFP （an oncolytic adenovirus） and Ad-hTERT （replication-defective adenovirus armed with small interference RNA targeting hTERT gene） with three consecutive daily at 7 ×10s pfu/day or treated with PBS as a control.The expression of E1A and hTERT, and apoptosis of tumor xenografts were assessed by immunohistochemical technique at the 7th day after injections. The tumor volume was measured at the 50th day after injections. Results The tumor volume in ZD55-hTERT treatment group （ 124.1 ± 27.5） was significantly less than that in ZD-EGFP （499.8 ±77.1 ） and Ad-hTERT （609.0 ± 102.5） treatment groups. The E1A positive expression in ZD55-hTERT treatment group was significantly higher than that in Ad-hTERT treatment group. The hTERT positive expression in ZD55-hTERT treatment group was significantly lower than that in Ad-hTERT treatment group. ZD55-hTERT treatment of tumor xenografts resulted in an increased apoptotic cell death as compared with ZD55-EGFP and Ad-hTERT treatment. Conclusion The antitumor effect of ZD55-hTERT was more potent than oncolytic adenovirus ZD55-EGFP and Ad-hTERT.