CpG-ODN下调HeLa细胞功能性Fas配体的表达

为观察CpG-ODN对宫颈癌细胞系HeLa细胞Fas配体(FasL)表达水平的影响,探讨其对由HeLa细胞Fas-FasL途径诱导的淋巴细胞凋亡作用。采用实时荧光RT-PCR方法检测HeLa细胞、正常宫颈上皮细胞中FasL和Jurkat T淋巴细胞中Fas的表达水平,应用HeLa细胞与Jurkat细胞共培养的方法体外研究HeLa细胞FasL诱导T淋巴细胞凋亡作用。结果显示:①HeLa细胞、正常宫颈上皮细胞中FasL表达阳性,其表达水平分别是(0.99±0.05)、(0.68±0.03),差别具有统计学意义(P=0.0007);Jurkat细胞Fas表达呈阳性;②HeLa细胞与Jurkat细胞共培养后Jurkat细胞的凋亡率为(38.23%±4.98%),应用抗体NOK-2中和HeLa细胞的FasL后,Jurkat细胞凋亡率减少为(3.54%±1.61%),两者相比,差别有显著性意义(P=0.0001);③HeLa细胞用CpG-ODN处理前后FasL的表达水平分别是(0.99±0.05)、(0.79±0.04),差别有统计学意义(P=0.005);CpG-ODN预处理的HeLa细胞与Jurkat细胞共培养后Jurkat细胞凋亡率为(6.41%±2.81%),而没有用CpG-ODN预处理的HeLa细胞与Jurkat细胞共培养Jurkat细胞凋亡率为(29.23±6.85)%,二者的差别有统计学意义(t=13.39,P=0.006)。HeLa细胞可能通过表达FasL主动诱导T淋巴细胞凋亡从而在肿瘤的免疫逃逸中发挥作用,CpG-ODN可通过下调FasL的表达而减少肿瘤细胞主动诱导的T淋巴细胞凋亡。

CpG-ODN down-regulates the expression of the functionally active Fas ligand in HeLa cells

To explore the effect of CpG-ODN on the expression level of the functionally active Fas ligand(FasL) in HeLa cells and its role on apoptosis of lymphocytes induced by Fas-FasL signaling pathway,the expression of FasL in HeLa cells and normal cervical epithelial cells as well as the expression of Fas in Jurkat lymphoma T cells were assayed fluorescent quantitative RT-PCR,and the apoptosis of lymphocytes induced by FasL was examined by co-culture assay of HeLa cells and Jurkat lymphoma T cells in vitro with flow cytometry.It was demonstrated that the expression levels of FasL in HeLa cells and normal cervical epithelial cells were(0.99±0.05) and(0.68±0.03) respectively,with significant difference between these two goups(P=0.0007).In addition,Jurkat lymphoma T cells expressed Fas,and the apoptotic rate of Jurkat lymphoma T cells in the co-cultures of HeLa cells and Jurkat lymphoma T cells was(38.23%±4.98%).When the activity of FasL in HeLa cells was neutralized with FasL-neutralizing antibody NOK-2,the apoptotic rate was reduced to(3.54%±1.61%)(P=0.0001).Meanwhile,the expression levels of FasL in HeLa cells before and after treatment with CpG-ODN were(0.99%±0.05%) and(0.79%±0.04%),respectively(P=0.005),while the apoptotic rate of the co-cultures of HeLa cells pre-treated with CpG-ODN and Jurkat lymphoma T cells was(6.41%±2.81%),but that without treatment with CpG-ODN was(29.23%±6.85%)(P=0.006).It suggests that HeLa cells might evade the immune surveillance through expression of FasL to induce apoptosis of T lymphocytes,and the role of CpG-ODN is to down-regulate the expression of FasL in order to decrease the active induction of apopotosis in T lymphpcytes.