Nrf2/CaMKII通路介导EMT促舌鳞癌恶性表型及干性转化的机制研究

Abnormal activation of Nrf2 can faciliate the EMT, malignant phenotype, and stemness transformation of tumor. However, the exact mechanisms are not yet clear. The applicant’s previous studies showed that the high expression level of Nrf2 was closely related to the malignant degree of tongue squamous cell carcinoma (TSCC). In SCC25/CD44+ stem cells, Nrf2 can directly interact with calcium/ calmodulin-dependent protein kinase (CaMKII). Morover, interference of Nrf2 could induce a significant decline of phosphorylation level of CaMKII. Plumbagin could inhibit Nrf2 as well as marker proteins of EMT and stemness in TSCC cells. Based on our previous studies and studies from other groups, we deduce that Nrf2/CaMKII pathway can promote the malignant phenotype and stemness transformation by modulation of EMT in TSCC. Plumbagin can reverse the malignant phenotype and stemness transformation by suppressing Nrf2/CaMKII pathway. To clarify this deduction, we plan to analyze the correlation of Nrf2/CaMKII pathway and clinical data in TSCC spcimens. The study will be carried out in TSCC stem cell and nude mouse model; We will apply the techniques of siRNA and lentivirus transfection to regulate the expression level of Nrf2/CaMKII pathway, thus to elucidate the mechanisms of Nrf2/CaMKII pathway on the malignant phenotype and stemness transformation by modulation of EMT in TSCC. This project aims to give clues to the treatment for TSCC by inhibiting or reversing of EMT and stemness of TSCC.

Nrf2的异常激活具有促进肿瘤上皮间质转化（EMT）乃至恶性表型及干性转化作用，但机制尚未明晰。申请人前期发现：①Nrf2高表达水平与舌鳞癌恶性进展相关。舌鳞癌SCC25/CD44+干细胞中Nrf2与钙离子/钙调素依赖性蛋白激酶（CaMKII）存在相互作用；干扰Nrf2后，CaMKII磷酸化表达水平显著下降。②白花丹素能抑制舌鳞癌细胞中Nrf2表达，且EMT和干性标志蛋白表达均被抑制。据此假设：Nrf2/CaMKII通路介导EMT促进舌鳞癌恶性表型及干性转化；白花丹素通过抑制该通路阻断EMT从而逆转舌鳞癌恶性表型及干性转化。本课题拟从分析通路在舌鳞癌表达的相关性入手，建立舌鳞癌干细胞、裸鼠移植瘤模型，应用siRNA及慢病毒转染技术干预通路，从体内外揭示Nrf2/CaMKII通路介导EMT促舌鳞癌恶性表型及干性转化的作用机制，旨在为抑制/逆转舌鳞癌EMT和干性转化提供新的理论依据和治疗方案。

舌鳞状细胞癌（简称舌鳞癌）（tongue squamous cell carcinoma, TSCC）是头颈部最常见的恶性肿瘤，区域淋巴结转移率高，具有很高的复发率和死亡率。尽管采用手术、放疗及化疗的综合治疗，较高的复发和转移限制了舌鳞癌疗效的进一步提高，舌鳞癌死亡患者几乎均伴有转移，迄今尚未找到理想的治疗靶点控制舌鳞癌的恶性进程。核因子 E2 相关因子2（nuclear factor erythroid-2 related factor 2, Nrf2）的异常激活具有促进肿瘤上皮间质转化（epithelial-mesenchymal transition, EMT）乃至恶性表型及干性转化作用，但机制尚未明晰。项目组前期发现：Nrf2高表达水平与舌鳞癌恶性进展相关。舌鳞癌干细胞中Nrf2与钙离子/钙调素依赖性蛋白激酶（CaMKII）存在相互作用。白花丹素能抑制舌鳞癌细胞中Nrf2表达，且EMT和干性标志蛋白表达均被抑制。据此，我们推测Nrf2/CaMKII通路介导EMT促进舌鳞癌恶性表型及干性转化；白花丹素通过调控该通路阻断EMT从而逆转舌鳞癌恶性表型及干性转化。本研究建立了舌鳞癌干细胞、裸鼠原位移植瘤模型，应用shRNA及慢病毒转染技术干预通路，阐明了Nrf2/CaMKII通路介导EMT是舌鳞癌恶性表型及干性转化的作用机制，白花丹素能够通过调控Nrf2/CaMKII通路阻断EMT从而逆转舌鳞癌恶性表型及干性转化。本研究为抑制/逆转舌鳞癌EMT和干性转化提供了新的理论依据和治疗方案。