shRNA-CXCR7联合TRAIL对人肝癌SMMC-7721细胞裸鼠皮下移植瘤生长的影响

Effect of shRNA-CXCR7 combined with TRAIL on subcutaneous transplantation tumor of SMMC-7721 cell line in nude mice

目的探讨重组腺病毒介导的细胞表面趋化因子受体7(C-X-C chemokine receptor type 7,CXCR7)基因沉默联合肿瘤坏死因子相关凋亡诱导配体(TNF related apoptosis inducing ligand,TRAIL)对人肝癌SMMC-7721细胞裸鼠皮下移植瘤生长的影响。方法建立肝癌SMMC-7721细胞裸鼠皮下移植瘤模型,2周后,当裸鼠肿瘤体积达到50~100 mm^3后,将20只造模成功的裸鼠随机分为4组并标记(n=5),分别接受瘤内注射治疗:空白组、TRAIL组、shRNA-CXCR7组和TRAIL+shRNA-CXCR7组。对各组荷瘤鼠用卡尺在体测量瘤体长短径后进行瘤体内注射,1次/7 d。并绘制裸鼠移植瘤生长曲线。第5次注射治疗后1周处死全部裸鼠,小心剥离肿瘤并进行瘤体重量称量。免疫组化和Western blot检测各组移植瘤组织中血管内皮细胞生长因子(vascular endothelial cell growth factor,VEGF)的表达。结果治疗开始到第7天,TRAIL组、shRNA-CXCR7组和TRAIL+shRNA-CXCR7组均较空白组肿瘤生长缓慢(P<0.05);从第14天到35天,TRAIL组移植瘤体积增长迅速与空白组间差异无统计学意义,而shRNA-CXCR7组和TRAIL+shRNA-CXCR7组裸鼠移植瘤体积增长缓慢;35 d实验结束时,与其他各组相比TRAIL+shRNA-CXCR7组肿瘤体积增幅最小(P<0.05)。第35天时,shRNA-CXCR7组和TRAIL+shRNA-CXCR7组肿瘤平均瘤重明显小于空白组和TRAIL组,其中TRAIL+shRNACXCR7组瘤体质量最轻(P<0.05)。免疫组化结果及Western blot结果显示:TRAIL组、shRNA-CXCR7组和TRAIL+shRNA-CXCR7组3组VEGF阳性表达均低于空白组,其中以TRAIL+shRNA-CXCR7组表达最低(P<0.05)。结论下调CXCR7的表达联合TRAIL可通过调节VEGF的表达来抑制肝癌SMMC-7721裸鼠皮下移植瘤的生长进展。

Objective To investigate the effect of C-X-C chemokine receptor type 7（ CXCR7） gene silencing combined with TNF related apoptosis inducing ligand（ TRAIL） on the growth of human hepatocellular carcinoma SMMC-7721 cells in nude mice. Methods The subcutaneous transplanted tumor model of hepatoma cell line SMMC-7721 in nude mice was established. After two weeks,the 20 successful nude mice models were randomly divided into four groups（ n = 5） and marked when the tumor volume of nude mice reached 50-100 mm^3： blank group,TRAIL group,shRNA-CXCR7 group and TRAIL ＋ shRNA-CXCR7 group that received intratumoral injection therapy respectively. The tumor size in vivo by calipers was measured every7 days and the growth curve of transplanted tumor in nude mice was drawed. All nude mice were killed after the fifth injection treatment and weighted the tumor of each group. The expression of vascular endothelial cell growth factor（ VEGF） in transplanted tumor tissues was detected by immunohistochemistry and Western blot. Results Compared with the blank group,the tumor of the TRAIL group,shRNA-CXCR7 group and TRAIL ＋shRNA-CXCR7 group growed slowly on 7thday（ P〈0. 05）. From the 14 thday until the 35 thday,the tumor volume of the TRAIL group growed rapidly,there was no statistical significance between TRAIL group and blank group,while the tumor volume of shRNA-CXCR7 group and TRAIL ＋ shRNACXCR7 group still growed slowly. At the end（ on the 35thday）,the tumor volume of TRAIL ＋ shRNA-CXCR7 group increase minimum,and there were statistical significance compared with other groups（ P〈0. 05）. The average tumor weight of shRNA-CXCR7 group and TRAIL ＋ shRNA-CXCR7 group were significantly smaller than those of blank group and TRAIL group,and the weight of TRAIL ＋ shRNA-CXCR7 group was the lightest（ P〈0. 05）.Immunohistochemistry and Western blot results： the positive expression of VEGF in TRAIL group,shRNA-CXCR7 group and TRAIL ＋ shRNA-CXCR7 group were lower than that in blank group,and the TRAIL ＋ shRNA-CXCR7 expression minimum（ P〈0. 05）. Conclusion Down-regulation of CXCR7 combined with TRAIL could significantly inhibit the growth of subcutaneous transplantation tumor of SMMC-7721 cell line in nude mice through regulating the expression of VEGF.