EB病毒促进鼻咽癌血管拟态形成及其机制研究

Neovascularization plays an important role in tumor occurrence, development, recurrence and metastasis of nasopharyngeal carcinoma (NPC). It is becoming clear that vasculogenic mimicry (VM) is another important mechanism in tumor neovascularization. Our previous studies suggested that Epstein-Barr virus (EBV) infected NPC cells significantly enhanced VM formation and tumor growth which were decreased after elimination of EBV by CRISPR/CAS9 system in vitro and in vivo. Based on EBV infection can affect AKT activation and HIF-1α expression in nuclei, we speculate that EBV may promote the formation of VM through AKT/HIF-1α signaling pathway. On the basis of the preliminary work, chemical blockers、 specific shRNA silencing、 western blot、 immunofluorescence and other technology were used to observe the role of AKT/HIF-1α in VM formation of EBV in nasopharyngeal carcinoma in vitro and in vivo and explore the downstream target molecules of AKT/HIF-1α to promote VM formation; clinical samples to further analyze the above phenomena and mechanisms, and the relationship with the prognosis of patients. This project will not only benefit to understand the molecular mechanisms of VM formation in NPC, but also provide new targets for anti-angiogenesis therapy in the treatment of NPC.

新生血管在鼻咽癌的发生、发展、复发和转移中起重要作用,血管拟态(vasculogenic mimicry, VM)是肿瘤新生血管形成的另一机制。申请者前期发现：被Epstein Barr病毒（EBV）感染的鼻咽癌细胞体内外VM的形成能力和裸鼠皮下成瘤能力明显增加。利用CRISPR-CAS9技术敲除维持EBV复制的关键分子EBNA1，能够逆转以上现象。基于EBV感染能够影响AKT活化和核内HIF-1α表达，我们推测：EBV通过AKT/HIF-1α信号通路促进鼻咽癌VM形成。本项目拟在前期工作基础上，进一步通过化学阻断、特异shRNA、Westernblot、免疫荧光等方法体内外明确AKT/HIF-1α介导EBV促进鼻咽癌VM形成的作用并探讨其下游关键靶分子；临床标本验证上述现象和机制及与患者预后关系。通过本项目，不但能完善鼻咽癌VM的形成及其分子机制，也将为临床鼻咽癌抗血管治疗提供新靶点。

EB病毒（Epstein-Barr virus, EBV）与多种恶性肿瘤密切相关，其中80%为上皮恶性肿瘤，这主要包括鼻咽癌 (nasopharyngeal carcinoma, NPC) 。然而EBV在鼻咽癌中扮演的角色尚未完全弄清。本研究揭示了EBV对鼻咽癌中血管拟态和血小板凝集形成的作用及其机制。鼻咽癌细胞感染EBV后能够形成肿瘤血管网状结构，即血管拟态，从而促进肿瘤生长，这种血管拟态结构异于传统血管内皮细胞并且不依赖于VEGF。此外，鼻咽癌细胞感染EBV后能够通过诱导血小板凝集抵制NK细胞杀伤肿瘤。究其机制，血管拟态方面主要是由于EBV通过激活PI3K-AKT-HIF-1α信号通路，血小板凝集方面主要是通过F3细胞因子。通过小鼠移植瘤和临床样本验证EBV确实与PI3K-AKT-HIF-1α信号通路活化、血管拟态和，血小板凝集相关。进一步将HIF-1α 小分子靶向药物与传统抗VEGF血管靶向药物联用，TFPI与NK细胞治疗联用，具有协同抗肿瘤作用。该研究不仅阐明了EBV能够使鼻咽癌恶性上皮细胞向内皮细胞表型转变，也为靶向EBV抗肿瘤免疫治疗策略提供依据。