沉默生存素基因联合放疗对裸鼠移植人肝癌的抑瘤效应

Anti-tumor Effect of RNA Interference Silencing Survivin Gene Combined with X-ray Irradiation on Human Hepatoma Xenograft in Nude Mice

目的探讨RNA干扰(RNA interference,RNAi)生存素(Survivin)基因联合X射线照射对裸鼠移植人肝癌细胞SMMC-7721的抑瘤效应。方法肿瘤局部注射脂质体包裹的靶向Survivin基因的RNA干扰质粒后,接受5Gy X射线照射,观察各组裸鼠治疗后不同时间肿瘤体积和平均存活时间,以免疫组化染色法检测肿瘤组织Survivin、增殖细胞核抗原(Proliferation Cell Nuclear Antigen,PCNA)表达和肿瘤间质微血管密度,以TUNEL法检测肝癌细胞凋亡。结果 治疗后第3～21d,RNA干扰联合放疗组肿瘤体积明显低于对照组、RNA干扰组和放疗组。RNA干扰联合放疗组裸鼠平均存活时间明显长于对照组、RNA干扰组和放疗组。治疗结束后第1天,RNA干扰联合放疗组裸鼠肿瘤增殖活性和微血管密度明显低于RNA干扰组和放疗组,且凋亡细胞百分数明显升高。结论 RNA干扰Survivin基因联合放疗可有效地抑制裸鼠移植人肝癌细胞增殖和血管生成,促进细胞凋亡,其抑瘤效应明显优于放疗和RNA干扰治疗。

Objective To investigate the anti-tumor effect of RNA interference silencing Survivin gene combined with X-ray irradiation on human hepatoma xenograft in nude mice.Methods siRNA expression plasmids targeting Survivin genes packed by liposome were injected into human hepatoma xenograft which were irradiated with 5 Gy X-ray later.Tumor volumes at different time points and mean survival period of mice were observed.Expression level of Survivin,PCNA and intratumoral microvessel density were detected by Immunohistochemical staining.Apoptotic cells in tumor tissue were detected by TUNEL method.Results Tumor volumes of pGenesil-survivin＋5 Gy group were significantly lower than those of the control,pGenesil-survivin and 5 Gy groups 3~21 days after the beginning of therapy.Mean survival period of mice in pGenesil-survivin＋5 Gy group was the longest.Expression level of PCNA and intratumoral microvessel density in pGenesil-survivin＋5 Gy group were significantly lower than those of pGenesil-survivin group and radiotherapy group 1 day after therapy.Percentage of apoptotic cells in tumor tissue in pGenesil-survivin＋5 Gy group was significantly higher than other groups.Conclusion RNA interference silencing Survivin gene combined with radiotherapy could effectively inhibit cell proliferation and tumor angiogenesis,enhance apoptosis in tumor xenograft and its anti-tumor effect was more powerful than that of radiotherapy or RNA interference silencing Survivin gene.