Zhu Yimin, Zhong Zhengxiang, Liu Zhiming
Department of General Surgery, The Second Hospital of Jiaxing, Jiaxing, PR China.
Scand J Gastroenterol. 2011 Jan;46(1):53-9. doi: 10.3109/00365521.2010.510566. Epub 2010 Sep 1.
Let-7a, a molecule that is reduced in various cancers, has been associated with cell growth and proliferation. Upregulation of let-7a may inhibit tumor cell growth. To verify this hypothesis, let-7a gene overexpression was studied in gastric cancer cells in vitro and in vivo.
A lentiviral system harboring both enhanced green fluorescent protein reporter gene and the let-7a short hairpin RNA expression cassette was firstly constructed. Then the stable let-7a gene overexpression SGC-7901 cells were established and real-time RT-PCR analysis was used to evaluate the expression of the let-7a gene. Their growth-inhibiting, cell cycle arrest characteristics were identified.
In SGC-7901/let-7a cells, let-7a expression was significantly increased. Their proliferation was obviously retarded and the cell cycle changed with increased G0/G1 arrest and decreased S phase. In animal experiments, SGC-7901/let-7a cell xenografts demonstrated growth suppression compared to parental or control gastric cancer cell xenografts.
The results demonstrated that lentiviral vector was capable of upregulating let-7a, resulting in impressive anticancer effects. It offers a powerful new strategy for the development of novel therapeutic interventions to treat human gastric carcinomas.
Let-7a在多种癌症中表达降低,与细胞生长和增殖有关。上调Let-7a可能抑制肿瘤细胞生长。为验证这一假设,对胃癌细胞进行了体内外Let-7a基因过表达研究。
首先构建携带增强型绿色荧光蛋白报告基因和Let-7a短发夹RNA表达盒的慢病毒系统。然后建立稳定的Let-7a基因过表达SGC-7901细胞,并采用实时RT-PCR分析评估Let-7a基因的表达。鉴定其生长抑制和细胞周期阻滞特性。
在SGC-7901/Let-7a细胞中,Let-7a表达显著增加。其增殖明显受阻,细胞周期发生改变,G0/G1期阻滞增加,S期减少。在动物实验中,与亲本或对照胃癌细胞异种移植相比,SGC-7901/Let-7a细胞异种移植表现出生长抑制。
结果表明慢病毒载体能够上调Let-7a,产生显著的抗癌效果。它为开发治疗人类胃癌的新型治疗干预措施提供了一种强有力的新策略。