三种重构型人caspase-8促宫颈癌HeLa细胞凋亡的效率

Pro-apoptotic Efficiencies of Three Reconstructed Human caspase-8 on Cervical Cancer Cell Line HeLa

背景与目的细胞凋亡是一种进化上高度保守的细胞死亡方式,将高活性的促凋亡分子靶向性地导入肿瘤细胞而诱导肿瘤细胞凋亡是肿瘤基因治疗的潜在策略。在证实了大、小亚基次序颠倒的重构型人caspase-8具有持续的诱导宫颈癌细胞HeLa凋亡活性的基础上,本研究旨在分析3种重构型人caspase-8(Casp8CD、Rev8和Rev8L)促HeLa细胞凋亡的效率,探讨重构型人caspase-8作为诱导肿瘤细胞凋亡候选分子的可行性。方法脂质体法将Casp8CD、Rev8和Rev8L基因的pIRES2鄄EGFP真核表达载体转染入人HeLa和MCF鄄7细胞,用荧光显微镜观察目的基因的表达及其促凋亡效应,MTT法和细胞计数法检测3种重构型人caspase鄄8基因表达产物的促凋亡效率。用生物信息学方法分析Rev8和Rev8L分子大、小亚基间连接肽段的柔性。结果荧光显微镜观察结果表明,3种重构型人caspase-8基因在HeLa和MCF-7细胞中得到表达,其中Rev8和Rev8L基因的表达能有效促进被转染细胞的凋亡,细胞表现为凋亡性容积减少(AVD)。MTT结果显示,Rev8和Rev8L基因转染组在转染后20h,A570值即开始明显降低(与对照组相比)。细胞计数结果表明,转染后24h,Casp8CD、Rev8和Rev8L基因转染组的细胞死亡率分别为16.9%、52.3%和47.7%,而转染后48h各组相应的细胞死亡率分别为12.9%、51.6%和61.2%?

BACKGROUND & OBJECTIVE: Apoptosis is a kind of evolutional high conservative cell death. Transferring high active pro-apoptotic molecules into cancer cells to induce apoptosis is a potential strategy for cancer gene therapy. Based on our previous generation of reconstructed human caspase-8, which can continuously induce apoptosis of cervical cancer cell line HeLa, by reversing its large and small subunits, this study was designed to investigate the pro-apoptotic efficiencies of 3 reconstructed human caspase-8 (Casp8CD, Rev8, and Rev8L) on HeLa cells, and to explore the feasibility of reconstructed human caspase-8 as potential apoptosis-inducing candidates. METHODS: The eukaryotic expression vectors pIRES2-EGFP carrying Casp8CD, Rev8, and Rev8L genes were transfected into HeLa cells, and breast cancer MCF-7 cells. Expressions and pro-apoptotic effects of Casp8CD, Rev8, and Rev8L genes were observed under fluorescent microscope, and their pro-apoptotic efficiencies were assessed by MTT assay and cells counting. The flexibilities of linking-peptides between subunits of Rev8 and Rev8L were analyzed by bioinformatics. RESULTS: Expressions of the 3 reconstructed caspase-8 genes were observed under fluorescent microscope, and the HeLa and MCF-7 cells expressing Rev8 or Rev8L genes displayed typical apoptotic volume decrease (AVD). MTT assay showed that compared with control cells, A570 values of Rev8- and Rev8L-transfected cells began to decrease 20 h after transfection. Cell counting results indicated that cell death ratio of Casp8CD-, Rev8-, and Rev8L-transfected cells were 16.9%, 52.3%, and 47.7%, respectively, 24 h after transfection; and 12.9%, 51.6%,and 61.2%,respectively,48 h after transfection. Bioinformatics analysis showed that the linking-peptides between subunits of Rev8 and Rev8L were flexible. CONCLUSION:Rev8 and Rev8L molecules have similar pro-apoptotic effects and efficiencies, but over-expressed Casp8CD had no significant pro-apoptotic effects.