甲硫氨酸饥饿通过抑制程序性死亡配体1诱导胃癌细胞凋亡

目的 研究甲硫氨酸饥饿诱导胃癌细胞凋亡的分子机制。方法 TCGA数据库分析胃癌组织中PD-L1的表达；胃癌AGS细胞分为对照组、甲硫氨酸饥饿处理组、siPD-L1处理组、甲硫氨酸饥饿联合siPD-L1处理组,CCK-8检测胃癌细胞活力,AO/EB双染检测胃癌细胞凋亡数目,流式细胞仪检测胃癌细胞凋亡率,western blotting检测胃癌细胞PD-L1、Bcl-2、Bax、Caspase-3蛋白表达；Starbase数据库分析PD-L1与Bcl-2抗凋亡蛋白家族(BCL2A1,MCL1,BCL2,BCL2L1)之间的联系。结果 PD-L1在胃癌组织中高表达(P=0.0011),PD-L1的表达与胃癌G分级相关(P＜0.05)；甲硫氨酸饥饿和siPD-L1能够抑制胃癌细胞存活率(P＜0.05),促进凋亡(P＜0.05),抑制PD-L1和Bcl-2表达(P＜0.05),上调促凋亡蛋白Bax、Caspase-3表达(P＜0.05)；甲硫氨酸饥饿联合siPD-L1处理显示siPD-L1与甲硫氨酸饥饿起协同作用(P＜0.05)。PD-L1与Bcl-2抗凋亡蛋白家族之间存在正相关(P＜0.005)。结论 甲硫氨酸饥饿是通过抑制PD-L1的表达下调抗凋亡蛋白Bcl-2、上调促凋亡蛋白Bax、Caspase-3表达从而诱导胃癌细胞凋亡。

Methionine starvation induces apoptosis of gastric cancer cells by inhibiting programmed death ligand-1

Purpose To study the molecular mechanism of methionine starvation induced apoptosis in gastric cancer cells. Method Analysis of PD-L1 expression in gastric cancer tissues by TCGA database. Gastric cancer AGS cells were divided into control group, methionine starvation treatment group, siPD-L1 treatment group, methionine starvation combined with siPD-L1 treatment group, CCK-8 detection the cell viability of gastric cancer, AO/EB double staining was used to detect the apoptosis of gastric cancer cells, the apoptosis rate of gastric cancer cells was detected by flow cytometry. The expressions of PD-L1, Bcl-2, Bax and Caspase-3 were detected by western blotting. The Starbase database analyzes the association of PD-L1 with Bcl-2 anti-apoptotic protein family (BCL2A1, MCL1, BCL2, BCL2L1). Result PD-L1 was highly expressed in gastric cancer tissues (P=0.0011), and the expression of PD-L1 was correlated with G grade of gastric cancer (P<0.05). Methionine starvation and siPD-L1 could inhibit the survival rate of gastric cancer cells (P<0.05), promote apoptosis (P<0.05), inhibit PD-L1 and Bcl-2 expression (P<0.05), up-regulate the expression of proapoptotic proteins Bax and Caspase-3 (P<0.05); methionine starvation combined with siPD-L1 Comparison of treatment showed synergy between siPD-L1 and methionine starvation(P<0.05). There was a positive correlation between PD-L1 and Bcl-2 anti-apoptotic protein family(P<0.005). Conclusion Methionine starvation induces apoptosis of gastric cancer cells by inhibiting the expression of PD-L1 and down-regulating the anti-apoptotic protein Bcl-2 to up-regulate the expression of Bax and Caspase-3.