程序性细胞死亡因子4过表达对胃癌细胞BGC823凋亡及凋亡调控蛋白的影响

Effect of programmed cell death 4 over-expression to apoptosis and apoptosis related protein in BGC823 cells

目的通过稳定转染程序性细胞死亡因子4(programmed cell death 4,PDCD4)基因至胃癌细胞BGC823中,观察过表达PDCD4对BGC823凋亡的作用及对凋亡相关调控蛋白Akt/p-Akt、FLIP、caspase-8及cleaved-caspase-8的影响。方法构建针对人PDCD4的真核表达载体并转染至BGC823细胞,Annexin V-FITC/PI联合流式细胞仪检测细胞凋亡,Western Blot检测蛋白的表达。结果成功构建PDCD4真核表达载体并转染至BGC823中,获得稳定过表达PDCD4的细胞模型,过表达PDCD4的BGC823细胞凋亡率(10.82%±1.29%)较未转染组(5.06%±0.83%)明显升高(P<0.05)。转染PDCD4后,Akt/p-Akt表达(0.25±0.04/0.06±0.01)较未转染组(0.65±0.09/0.18±0.02)明显降低(P<0.01),FLIP蛋白在转染组中的表达(0.12±0.01)较未转染组中的表达(0.48±0.06)明显降低(P<0.01),而转染组caspase-8(0.36±0.07)及cleaved-caspase-8(0.24±0.05)较未转染组caspase-8(0.18±0.04)及cleaved-caspase-8(0.11±0.02)明显升高(P<0.05)。结论PDCD4过表达可促进胃癌细胞BGC823的凋亡,并且抑制Akt和FLIP的表达,从而促进caspase-8的活性。

Objective To observe the effect of over-expression of programmed cell death 4 （PDCD4） to apoptosis and apoptosis related protein Akt/p-Akt, FLIP and caspase-8/cleaved-caspase-8 in BGC823 cells. Methods PDCD4 was infected into BGC823 cells by eukaryotic expression vector. The apoptosis was detected by Annexin V-FITC/PI double staining combined with flow cytometer. Western Blot analysis was used to examine the expression of PDCD4, protein and apoptosis related proteins above mentioned. Results The PDCD4 over-expressing cell model was obtained after PDCD4 being infected into BGC823 cells. The apoptotie rate of BGC823 cells over-expressing PDCD4 （10.82% ± 1.29% ） was significant elevated compared with control cells （5.06% ± 0.83% ） （P 〈 0.05）. Over-expression of PD- CD4 caused an obvious decrease of Akt/p-Akt （0.25 ± 0.04/0.06 ± 0.01 ） and FLIP （0.12 ± 0.01 ） compared with expression in control cells （0.65 ± 0.09/0. 18 ± 0.02 and 0.48 ± 0.06） （ P 〈 0.01 ）. However, the expression of caspase-8/cleaved-caspase-8 in infected BGC823 cells （0.36 ± 0.07/0.24± 0.05） increased compared with control cells （0.18 ± 0.04/0. 11 ± 0. 02） （P 〈 0.05 ）. Conclusion PDCD4 over-expression enhanced the apoptosis in BGC823 cells down-regulated Akt,activity and FLIP expression but up-regulated the activity of caspase-8.