Department of Oncology, Nanfang Hospital, Guangzhou 510515, China.
Biomed Pharmacother. 2011 Jun;65(3):168-74. doi: 10.1016/j.biopha.2011.02.005. Epub 2011 May 5.
This work aimed to investigate the role of the Ras signaling pathway in cetuximab resistance in human nasopharyngeal carcinoma (hNPC). An hNPC 5-8F cell line was induced by stepwise exposure to increasing doses of cetuximab. Western blot was conducted to detect protein levels. Our results are as follows: cetuximab-resistant hNPC 5-8F/Erbitux cell lines were successfully developed. After treatment with cetuximab for 3 and 5 d, the RI was 1.2 and 1.1, respectively. Compared with the 5-8F cells, the protein expression levels of H-ras, JNK/P-JNK, P-ERK1/2, p38/P-p38, P-AKT, NF-κB p65/P-NF-κB p65 and c-fos were significantly increased in the 5-8F/Erbitux cells (P=0.000 for all); however, the protein expression levels of ERK1/2 and c-jun/P-c-jun were significantly decreased (P=0.000 for all) and AKT protein expression showed no significant change (P=0.176). After the 5-8F/Erbitux cells were transfected with H-ras shRNA, H-ras protein expression was significantly decreased (P=0.000) and cetuximab sensitivity improved. In contrast, in the 5-8F/Erbitux+siH-ras cells, protein expression levels of P-ERK1/2, P-JNK, P-AKT and NF-κB p65/P-NF-κB p65 were significantly decreased (P=0.000 for all). Additionally, protein expression levels of JNK, ERK1/2, p38/P-p38 and c-jun/P-c-jun were significantly increased (P=0.000 for all), but protein expression levels of AKT and c-fos did not change significantly (P=0.061 and P=0.068, respectively). In conclusion, the activation of the H-ras/ERK1/2, H-ras/JNK and PI3K-AKT signaling pathways is closely associated with cetuximab resistance in 5-8F/Erbitux cells. NF-κB is activated in 5-8F/Erbitux cells without activation of c-jun.
本研究旨在探讨 Ras 信号通路在人鼻咽癌（hNPC）中西妥昔单抗耐药中的作用。通过逐步暴露于递增剂量的西妥昔单抗诱导 hNPC 5-8F 细胞系。采用 Western blot 检测蛋白水平。结果如下：成功建立了西妥昔单抗耐药的 hNPC 5-8F/Erbitux 细胞系。用西妥昔单抗处理 3 和 5 d 后，RI 分别为 1.2 和 1.1。与 5-8F 细胞相比，5-8F/Erbitux 细胞中 H-ras、JNK/P-JNK、P-ERK1/2、p38/P-p38、P-AKT、NF-κB p65/P-NF-κB p65 和 c-fos 的蛋白表达水平显著增加（均 P=0.000）；然而，ERK1/2 和 c-jun/P-c-jun 的蛋白表达水平显著降低（均 P=0.000），AKT 蛋白表达无明显变化（P=0.176）。转染 H-ras shRNA 后，5-8F/Erbitux 细胞 H-ras 蛋白表达显著降低（P=0.000），西妥昔单抗敏感性提高。相反，在 5-8F/Erbitux+siH-ras 细胞中，P-ERK1/2、P-JNK、P-AKT 和 NF-κB p65/P-NF-κB p65 的蛋白表达水平均显著降低（均 P=0.000）。此外，JNK、ERK1/2、p38/P-p38 和 c-jun/P-c-jun 的蛋白表达水平显著增加（均 P=0.000），但 AKT 和 c-fos 的蛋白表达水平无明显变化（P=0.061 和 P=0.068）。综上所述，H-ras/ERK1/2、H-ras/JNK 和 PI3K-AKT 信号通路的激活与 5-8F/Erbitux 细胞中的西妥昔单抗耐药密切相关。在 5-8F/Erbitux 细胞中，NF-κB 被激活而 c-jun 未被激活。
