RNA干扰 Rac1基因表达对结直肠癌LoVo细胞骨架和细胞周期的影响

目的:观察Rac1蛋白在结直肠癌细胞中的表达,并分析其与结直肠癌LoVo细胞骨架、细胞周期和细胞凋亡的相关性.方法:Western blotting测定5种结直肠癌细胞株(LoVo,SW480,SW620,SW1116,HT29)中Rac1蛋白的表达；Rac1-shRNA质粒转染LoVo细胞后,激光共聚焦显微镜观察LoVo细胞骨架的变化,流式细胞仪检测细胞周期和细胞凋亡的变化.结果:5种结直肠癌细胞株中均有Rac1蛋白的高表达.Rac1基因沉默后,LoVo细胞中交联状态的F-actin网明显减少且紊乱,G0/G1期细胞比例较对照组显著增加(74.63 ±4.40)％ vs(56.46 ±3.09)％,P＜0.05],而S期细胞比例较对照组显著减少(12.87±1.77)％vs(29.66±1.92)％,P＜0.05]；Rac1-shRNA转染组LoVo细胞凋亡率较对照组显著增加(25.31±2.05)％vs(9.38±1.16)％,P＜0.05].结论:RNA沉默Rac1基因的表达影响了LoVo细胞骨架的形成和细胞周期,为以Rac1为靶点治疗结直肠癌提供了实验依据.

Silencing Rac1gene expression via RNA interference affects cytoskeleton and cell cycle of colorectal cancer LoVo cells

Objective:To detect the expression of Rac1 protein in colorectal cancer cells and to observe its correlation with cytoskeleton,cell cycle and apoptosis of colorectal cancer LoVo cells.Methods: The expression of Rac1 protein was detected by Western blotting in five colorectal cancer cell lines.The cytoskeleton changes were observed by confocal microscopy in LoVo cells transfected with Rac1-shRNA.The cell cycle and apoptosis were observed by flow cytometry in LoVo cells transfected with Rac1-shRNA.Results: Rac1 protein was highly expressed in five colorectal cancer cells.The cross-linked F-actin network was significantly reduced and disordered in LoVo cells transfected with Rac1-shRNA.The cell number in G0/G1 phase was significantly increased in Rac1-shRNA group compared with the control group(74.63±4.40]% vs 56.46±3.09]%,P<0.05),whereas it was reduced in S phase(12.87±1.77]% vs 29.66±1.92]%,P<0.05) and the apoptosis rate of LoVo cells was significantly increased in Rac1-shRNA group compared with the control group(25.31±2.05]% vs 9.38±1.16]%,P<0.05).Conclusion: Silencing Rac1 expression mediated by RNA interference affects the formation of cytoskeleton and the cell cycle of LoVo cells,which provides clinical evidence for Rac1-targeted treatment of colorectal cancer.