Liu Wenqi, Kang Min, Qin Yutao, Wei Zhuxin, Wang Rensheng
Department of Radiation Oncology, The First Affiliated Hospital of Guangxi Medical University Nanning 530021, Guangxi, China.
Int J Clin Exp Med. 2015 Feb 15;8(2):2182-9. eCollection 2015.
To investigate the apoptosis-inducing effects of cetuximab combined with radiotherapy and hypothermia in human nasopharyngeal carcinoma CNE cells. CNE cells were treated with the radiation monotherapy, the radiation and hypothermia, the cetuximab and radiation, and the triple-combination treatment, respectively. MTT assay was performed to assess cell proliferation following treatments. Hoechst 33258 staining and flow cytometry analyses were used to detect apoptotic process. Western blot analysis was performed to determine the protein expression levels. Cetuximab monotherapy inhibited the proliferation of CNE cells. Hyperthermia alone inhibited EGFR expression, and prolonged hypothermia treatment resulted in declining EGFR expression levels in these cells. Moreover, Hoechst 33258 staining showed obvious apoptotic morphologies in the treatment groups. Flow cytometry analysis showed that the interventions dramatically increased the apoptosis rates in CNE cells, with the most potent effect for the triple-combination treatment. Western blot analysis showed that, in the treatment groups, the expression levels of Bax were increased, while the expression levels of Bcl-2 were decreased, leading to significantly elevated Bax/Bcl-2 ratios in these groups, with the highest ratio for the triple-combination treatment. Cetuximab combined with radiotherapy and hypothermia treatments could efficiently inhibit the proliferation of CNE cells, and enhance the cellular apoptotic processes via regulating the expression levels of Bax and Bcl-2. Our findings provide experimental evidence for the application of the combination therapy in clinical treatment of nasopharyngeal carcinoma.
探讨西妥昔单抗联合放疗及低温对人鼻咽癌CNE细胞的凋亡诱导作用。分别采用单纯放疗、放疗与低温联合、西妥昔单抗与放疗联合以及三联疗法处理CNE细胞。采用MTT法评估处理后的细胞增殖情况。使用Hoechst 33258染色和流式细胞术分析检测凋亡过程。进行蛋白质印迹分析以确定蛋白质表达水平。西妥昔单抗单药治疗可抑制CNE细胞的增殖。单纯高温可抑制表皮生长因子受体（EGFR）表达，而长时间低温处理会导致这些细胞中EGFR表达水平下降。此外，Hoechst 33258染色显示各治疗组出现明显的凋亡形态。流式细胞术分析表明，这些干预措施显著提高了CNE细胞的凋亡率，其中三联疗法的效果最为显著。蛋白质印迹分析显示，在各治疗组中，Bax表达水平升高，而Bcl-2表达水平降低，导致这些组中Bax/Bcl-2比值显著升高，三联疗法组的比值最高。西妥昔单抗联合放疗及低温治疗可有效抑制CNE细胞的增殖，并通过调节Bax和Bcl-2的表达水平增强细胞凋亡过程。我们的研究结果为该联合疗法在鼻咽癌临床治疗中的应用提供了实验依据。
