CpG-ODN下调HeLa细胞功能性Fas配体的表达

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

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。

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 epi thelial 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 ex pression 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.