Background and objective: Tumor escape from the host immune system has been a major problem in immunotherapy of human malignancies. FasL/Fas-induced apoptosis plays an important role in various immunological processes. The aim of this study is to investigate the immune evasion in human lung carcinoma cell A549 induced by human lymphoma cell Jurkat via Fas/FasL pathway.
Methods: Jurkat cells and A549 cells were co-cultured at different proportions. The apoptotic rates of A549 cells were determined by flow cytometry (FCM). Protein levels of Fas, FasL and Caspase-8 in A549 cells were detected by Western blot.
Results: Survival rates of A549 cells gradually decreased and apoptotic rates of A549 cells were significantly enhanced along with ratio increasing between Jurkat and A549. Meanwhile, the protein levels of Fas and Caspase-8 gradually increased in A549 cells, and the protein levels of FasL had no significant difference in all groups.
Conclusions: The Jurkat cells might decrease the survival rates of A549 cells and enhanced its apoptosis and immune evasion partly via Fas/FasL pathway.
背景与目的: 当机体发生肿瘤时，肿瘤细胞可以多种方式逃避免疫系统的监控而分裂生长，这就是肿瘤的免疫逃逸。研究表明，肿瘤细胞自身凋亡减少以及机体免疫细胞凋亡增加是肿瘤免疫逃逸的重要机制。Fas/FasL系统是介导凋亡的重要分子体系，本研究旨在通过观察人淋巴瘤细胞株Jurkat诱导人肺癌细胞株A549凋亡过程中凋亡信号分子Fas、FasL及Caspase-8表达的改变，从而探讨Fas/FasL途径在肺癌细胞免疫逃逸中的作用。
方法: 人肺癌细胞株A549与人淋巴瘤细胞株Jurkat以不同比例分别进行共同培养，采用台盼蓝拒染法检测两种细胞存活率；流式细胞术（flow cytometry, FCM）检测两种细胞的凋亡率；Western blot技术检测A549细胞中Fas、FasL及Caspase-8蛋白表达水平。
结果: 随着Jurkat/A549细胞比例逐渐增大，A549细胞的凋亡率明显增加，Jurkat细胞凋亡率显著减少；同时A549细胞中Fas及Caspase-8蛋白的表达水平明显上调，而对FasL蛋白的表达水平无明显影响。
结论: Jurkat细胞可能通过Fas/FasL途径介导了人肺癌细胞株A549的凋亡，从而抑制了A549细胞的免疫逃逸。