AdVEGF-CDglyTK融合基因系统靶向治疗大肠癌的研究

目的 观察腺病毒介导的血管内皮细胞生长因子(VEGF)启动子驱动的CDglyTK融合双自杀基因系统(以下简称为AdVEGF-CDglyTK)对大肠癌的治疗作用,并结合研究结果进行作用机制的分析.方法 采用培养细胞移植法,将人大肠癌细胞系Lovo细胞接种于裸鼠背部皮下,建立裸鼠人大肠癌移植瘤模型.将20只裸鼠随机分为4组,每组5只.分组方法:Ⅰ组,注射重组腺病毒AdVEGF-CDglyTK与前药5氟胞嘧啶(5-FC)/丙氧鸟苷(GCV);Ⅱ组,仅注射前药5-FC/GCV;Ⅲ组:仅注射重组腺病毒AdVEGF-CDglyTK;Ⅳ组,空白对照,不施加任何处理.结果 RT-PCR结果显示:仅在Ⅰ组、Ⅲ组扩增出融合双自杀基因CDglyTK的片段.表型及各项病理指标的检测均显示第Ⅰ组裸鼠移植瘤的生长较其他3组显著受到抑制,而第Ⅱ、Ⅲ、Ⅳ组移植瘤的生长情况无明显差异;第Ⅰ组肿瘤细胞凋亡指数为38.65%±4.20%,较其他3组显著增加(F=397.530,P=0.000);第Ⅰ组肿瘤组织微血管密度计数为3.08±0.79,较其他3组显著减少(F=34.081,P=0.000).结论 AdVEGF-CDglyTK联合前药5-FC及GCV在体内可明显抑制大肠癌肿瘤的生长.其机制有二:首先该治疗系统可诱导裸鼠体内人大肠癌Lovo细胞的凋亡;其次该治疗系统在体内可明显抑制裸鼠体内大肠癌血管形成.

Targeting therapy for colorectal cancer with double suicide genes driven by VEGF promoter

Objective To investigate the curative effect of an adenovirus-mediated fusion gene system driven by VEGF promoter (AdVEGF-CDglyTK) on a nude mouse model of colorectal cancer and analyze the mechanism underlying its therapeutic effect.Methods The animal model of the colorectal cancer was established by using transplantation of the cultivated cells,human colorectal cell line LoVo,via subcutaneous injection on the back of nude mice.Twenty nude mice were equally divided into four groups:group Ⅰ received injection of AdVEGF-CDgiyTK plus 5-flurocytosine/ganciclovir(5-FC/GCV);group Ⅱwere given 5-FC/GCV;group Ⅲ were with AdVEGF-CDglyTK;group Ⅳ were used as control.Results CDglyTK was expressed exclusively in the tumor tissues from the group Ⅰ and Ⅲ by RT-PCR.The phenotype and pathological analysis showed that tumor growth was dramatically inhibited in group Ⅰwhen compared with other three groups,while no significant difference was found between group Ⅱ,group Ⅲ and group Ⅳ.The TUNEL assay demonstrated that the apoptosis rate of 38.65% ± 4.20 significantly increased in group Ⅰ when compared with other three groups (F = 397.530,P =0.000).The tumor microvessel density of 3.08±0.79 decreased significantly in group Ⅰ (F = 34.081,P = 0.000) when compared with other three groups.Conclusion The results suggested that AdVEGF-CDglyTK with 5-FC/GCV can inhibit the tumor growth of colorectal cancer significantly in vivo by a mechanism of systeminduced apoptosis and the efficient suppression of angiogenesis.