沉默FoxM1通过促进线粒体释放细胞色素C诱导口腔鳞癌细胞凋亡

目的:研究沉默叉头框蛋白M1 (FoxM1)基因对口腔鳞癌细胞凋亡影响及机制。方法:口腔鳞癌SCC9细胞感染FoxM1-shRNA慢病毒或阴性对照慢病毒,用RT-qPCR和Western blot测定沉默效果。MTT法测定细胞活力变化,平板克隆实验测定细胞克隆形成能力变化,流式细胞术测定细胞凋亡变化,Western blot测定细胞中cleaved caspase-3和cleaved caspase-9蛋白水平变化,JC-1法测定细胞线粒体膜电位变化,Western blot测定细胞线粒体和胞浆中细胞色素C(cytochrome C)蛋白水平的变化。结果:FoxM1-shRNA慢病毒感染成功下调口腔鳞癌细胞中FoxM1的表达(P0.05),阴性对照慢病毒对细胞中FoxM1表达水平没有影响。沉默FoxM1的口腔鳞癌细胞活力降低(P0.05),细胞克隆形成能力也降低(P0.05),细胞凋亡率及cleaved caspase-3和cleaved caspase-9蛋白水平均升高(P0.05),线粒体膜电位降低(P0.05),胞浆中cytochrome C蛋白水平升高(P0.05),线粒体中cytochrome C蛋白水平降低(P0.05)。结论:沉默FoxM1可以通过降低口腔鳞癌细胞线粒体膜电位、促进线粒体释放cytochrome C而诱导细胞凋亡。

Silencing of FoxM1 induces apoptosis of oral squamous-cell carcinoma cells by promoting mitochondrial release of cytochrome C

AIM: To study the effect of forkhead box protein M1 (FoxM1) silencing on apoptosis of oral squamous-cell carcinoma. METHODS: Oral squamous-cell carcinoma SCC9 cells were infected with FoxM1-shRNA lentivirus or negative control lentivirus. The silencing effect was measured by RT-qPCR and Western blot. The changes of cell viability effect was measured by MTT saay. The cell colony formation ability was measured by plate experiment. Flow cytometry was used to analyze the changes of apoptotic rate. Western blot was used to measure the protein levels of cleaved caspase-3 and cleaved caspase-9 in the cells. The changes of mitochondrial membrane potential were measured by JC-1 method. Western blot was used to measure the protein level of cytochrome C in the mitochondria and cytoplasm. RESULTS: Infection with FoxM1-shRNA lentivirus successfully reduced the expression of FoxM1 in oral squamous-cell carcinoma cells (P<0.05). Negative control lentivirus had no effect on the expression level of FoxM1 in the cells. The cell viability was reduced by FoxM1 silencing, and the ability of cell colony formation was also decreased. The apoptotic rate and the protein levels of cleaved caspase-3 and cleaved caspase-9 were all increased (P<0.05), and the mitochondrial membrane potential was decreased. The protein level of cytochrome C in the cytoplasm was increased, while the protein level of cytochrome C in the mitochondria was decreased (P<0.05). CONCLUSION: Silencing of FoxM1 induces the apoptosis of oral squamous-cell carcinoma cells by decreasing the mitochondrial membrane potential and promoting the release of cytochrome C from mitochondria.