肿瘤抑素抑制肝癌移植瘤生长的实验研究

Experimental study of tumstatin on growth of implanted liver cancer in nude mice

目的观察肿瘤抑素慢病毒载体对裸鼠肝癌移植瘤生长的抑制作用,探讨其在肝癌基因治疗中的应用前景。方法建立人肝癌细胞株SMCC-7721裸鼠皮下移植瘤模型,当肿瘤直径达到0.3～0.5cm时分别在瘤周及瘤体内多点注射100μl磷酸盐缓冲液(PBS组)、5×109TU慢病毒绿色荧光蛋白(Lenti-GFP组)和5×109TU肿瘤抑素重组慢病毒(Lenti-Tum组)。观察3组的肿瘤体积变化,采用RT-PCR和Western blotting法分别检测3组肿瘤组织中肿瘤抑素的mRNA和蛋白水平,并采用Kaplan-Meier法进行生存分析。结果注射21天后,Lenti-Tum组的肿瘤体积为(702.1±143.7)mm3,小于PBS组的(1622.2±253.8)mm3和Lenti-GFP组的(1538.5±284.9)mm3(P<0.05);Lenti-Tum组的抑瘤率为56.7%,显著高于Lenti-GFP组的5.2%(P<0.05);Lenti-Tum组中肿瘤抑素的mRNA和蛋白水平均高于其他两组。Lenti-Tum组小鼠的中位生存时间为100天,明显高于PBS组的58天和Lenti-GFP组的59天(P<0.05)。结论肿瘤抑素经慢病毒转染能够明显抑制肝癌移植瘤的生长,延长荷瘤裸鼠的生存时间。

Objective To investigate the inhibitory effect of tumstatin lentiviral vector （Lenti-Tum） on the growth of trans- planted hepatic carcinoma in nude mice and explore its possible application in the gene therapy of human hepatocarcinoma. Methods The subcutaneous hepatic carcinoma SMCC-7721 xenograft was successfully established in nude mice. Peri-tumoral and intra-tumoral injection of 100μl PBS （ PBS group）, 5×109 TU of green fluorescent protein lentiviral vector （ Lenti-GFP group） and 5 x 109 TU Len- ti-Tum （ Lenti-Tum group） were carried out in nude mice bearing human hepatic carcinoma xenograft. The tumor volumes of the three groups were observed. Reverse transcriptase polymerase chain reaction and Western blotting were employed to detect the mRNA and protein levels of tumstatin, respectively. The survival times of three groups were analyzed using the Kaplan-Meier method. Results The tumor volume of Lenti-Tum group was （702. 1±143.7） mm3, less than （ 1622. 2±253.8） mm3 in PBS group and （ 1538.5 ± 284.9） mm3 in Lenti-GFP group （ P 〈 0.05 ）. The inhibitory rate of Lenti-Tum group was 56. 7%, higher than 5.2% in Lenti-GFP group （ P 〈 0.05 ）. Both the mRNA and protein levels of tumstatin in Lenti-Tum group were higher than those in other two groups （ P 〈0. 05 ）. The median overall survival in Lenti-Tum group was 100 days, much longer than 58 days in PBS group and 59 days in Lenti- GFP group（P 〈 0.05）. Conclusion The Lenti-Tum can significantly inhibit the growth of hepatic carcinoma SMCC-7721 xenograft and prolong the overall survival time of nude mice.