Qin Zhen-Qi, Li Qi-Guang, Yi Hong, Lu Shan-Shan, Huang Wei, Rong Zhuo-Xian, Tang Yao-Yun, Xiao Zhi-Qiang
Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, China.
Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, Changsha, China.
Front Oncol. 2020 Feb 5;10:104. doi: 10.3389/fonc.2020.00104. eCollection 2020.
A heterozygous point mutation of p53 gene at codon 280 from AGA to ACA (R280T) frequently occurs in nasopharyngeal carcinoma (NPC) cell lines, and about 10% NPC tissues. However, the role of this mutation in the pathogenesis of NPC remains unclear. In this study, we generated p53 knockout (KO) NPC cell lines from CNE2 cells carrying heterozygous p53 R280T (p53-R280T) mutation and C666-1 cells carrying wild-type p53 by CRISPR-Cas9 gene editing system, and found that KO of heterozygous p53-R280T significantly decreased NPC cell proliferation and increased NPC cell apoptosis, whereas KO of wild-type p53 had opposite effects on NPC cell proliferation and apoptosis. Moreover, KO of heterozygous p53-R280T inhibited the anchorage-independent growth and tumorigenicity of NPC cells. mRNA sequencing of heterozygous p53-R280T KO and control CNE2 cells revealed that heterozygous p53-R280T mutation activated PI3K-Akt signaling pathway. Moreover, blocking of PI3K-Akt signaling pathway abolished heterozygous p53-R280T mutation-promoting NPC cell proliferation and survival. Our data indicate that p53 with heterozygous R280T mutation functions as an oncogene, and promotes the oncogenicity of NPC cells by activating PI3K-Akt signaling pathway.
p53基因第280位密码子由AGA突变为ACA（R280T）的杂合点突变在鼻咽癌（NPC）细胞系中频繁出现，在约10%的NPC组织中也有发生。然而，这种突变在NPC发病机制中的作用仍不清楚。在本研究中，我们通过CRISPR-Cas9基因编辑系统，从携带杂合p53 R280T（p53-R280T）突变的CNE2细胞和携带野生型p53的C666-1细胞中生成了p53基因敲除（KO）的NPC细胞系，发现杂合p53-R280T基因敲除显著降低了NPC细胞增殖并增加了NPC细胞凋亡，而野生型p53基因敲除对NPC细胞增殖和凋亡有相反的影响。此外，杂合p53-R280T基因敲除抑制了NPC细胞的非锚定依赖性生长和致瘤性。对杂合p53-R280T基因敲除的CNE2细胞和对照CNE2细胞进行mRNA测序显示，杂合p53-R280T突变激活了PI3K-Akt信号通路。此外，阻断PI3K-Akt信号通路消除了杂合p53-R280T突变对NPC细胞增殖和存活的促进作用。我们的数据表明，具有杂合R280T突变的p53发挥癌基因的作用，并通过激活PI3K-Akt信号通路促进NPC细胞的致癌性。
