TCEAL7基因对结直肠癌Caco2细胞的增殖、迁移、侵袭及凋亡的影响

Effect of transcription elongation factor A(SⅡ) like 7 on proliferation,migration,invasion and apoptosis of colorectal cancer cells

目的探讨TCEAL7[transcription elongation factor A(SⅡ)like 7]对结直肠癌细胞生物学功能的影响及可能的作用机制。方法应用RT-PCR检测TCEAL7在结直肠癌细胞Caco2、HT29、HCT116、SW480以及正常结直肠组织中的表达水平,筛选出低表达的细胞,将重组质粒p EZ-M98-TCEAL7及空质粒p EZ-M98通过脂质体Lipofectamine 2000转染Caco2细胞,应用RT-PCR及Western blot分别检测TCEAL7的mRNA以及蛋白表达水平;CCK-8和克隆形成实验检测细胞增殖活力,Transwell检测细胞迁移及侵袭能力,流式细胞术检测细胞凋亡;Western blot检测NF-κB及其下游靶基因蛋白表达的变化情况。结果 TCEAL7在结直肠癌细胞Caco2、HT29、HCT116、SW480中的mRNA表达量分别为(0.19±0.02)、(0.25±0.03)、(0.30±0.03)、(0.28±0.04),与正常结直肠组织(1.03±0.03)、(1.06±0.07)相比明显下降(P<0.01)。Caco2细胞转染组TCEAL7 mRNA和蛋白表达量分别为(1.08±0.13)、(1.01±0.15),均明显高于对照组[(0.43±0.20)、(0.53±0.10),P<0.01]。与对照组相比,转染组Caco2细胞的增殖、迁移及侵袭能力明显降低(P<0.01),细胞凋亡增加(P<0.01),NF-κB及其下游靶基因蛋白表达改变(P<0.01)。结论 TCEAL7在结直肠癌细胞中为低表达,过表达TCEAL7能抑制Caco2细胞增殖、迁移及侵袭,促进细胞凋亡,可能与NF-κB信号通路有关。

Objective To determine the effect of transcription elongation factor A （SⅡ） like 7 （TCEAL7） on the biological functions in colorectal cancer cells and investigate the underlying mechanism. Methods The expression of TCEAL7 in colorectal cancer cell lines Caco2, HT29, HCT116 and SW480, and normal colorectal tissues was investigated by RT-PCR in order to screen the colorectal cancer cells with low expression level of TCEAL7. Then, the recombinant plasmid pEZ-M98-TCEAL7 and blank vector pEZ-M98 were transfected into Caco2 cells by Lipofectamine 2000, the mRNA and protein levels of TCEAL7 were tested by RT-PCR and Western blotting respectively. CCK-8 assay and colony formation assay were applied to analyze the cell proliferation. Transwell chamber test was performed to measure the migration and invasion ability of the cells. Flow cytometry was conducted to analyze the cell apoptosis. Western blotting was employed to detect the protein expression changes of NF-κB and the downstream targets. Results The mRNA level of TCEAL7 in the colorectal cancer Caco2, HT29, HCT116 and SW480 cells was 0.19±0.02, 0.25±0.03, 0.30±0.03, and 0.28±0.04, respectively, significantly lower than those of normal colorectal tissues （1.03±0.03 and 1.06±0.07, P〈0.01）. The mRNA and protein levels of TCEAL7 in the pEZ-M98-TCEAL7 transfected group were significantly higher than those in the pEZ-M98 control group （1.08±0.13 vs 0.43±0.20, 1.01±0.15 vs 0.53±0.10, P〈0.01）. When compared to the control group, the transfected group had markedly inhibited cells proliferation, decreased abilities of migration and invasion （P〈0.01）, promoted cell apoptosis （P〈0.01）, and altered the protein expression of NF-κB and the downstream targets （P〈0.01）. Conclusion TCEAL7 is lowly expressed in colorectal cancer cell lines. Over-expression of TCEAL7 evidently inhibits the proliferation, migration and invasion, and induces apoptosis in colorectal cancer Caco2 cells,which may be through NFκB signaling pathway.