分割放射下，谷氨酸/EGLN1/SNAIL信号通路参与鼻咽癌放疗抵抗的作用机制研究

Radioresistance induced by fractionated irradiation is the underlying cause of local recurrence and treatment failure in nasopharyngeal carcinoma (NPC). However, the fundamental mechanism remains to be clarified..Our preliminary experimental results suggested that EglN1 was negatively correlated with the prognosis of NPC and down regulation of EglN1 was detected in radioresistant cell line CNE2R. EglN1 or VHL knock-out cell lines of NPC were resistant to radiation and Snail was upregulated in those cell lines. What’s more, the migration, invasion and radioresistance of NPC cell lines were enhanced through influence of glutamate. Thus, we hypothesize that EglN1 is the key factor which is associated with NPC radioresistance. EglN1 may inhibit NPC radioresistance through hydroxylating Snail, AKT and HIF1, which can be identified and degradated by VHL. Riluzole may enhance radiosensitivity through inhibiting extracellular glutamate and recovering activity of EglN1..NPC tissues, parental cell lines and radioresistant cell lines will be adopted as experimental subjects. CRISPR/Cas9, gene microarray techniques and bioinformatics tools will be used to reveal the molecular mechanism of glutamate/EglN1/SNAIL-mediated NPC radioresistance. Systemic studies of our project will provide basic theory and experimental evidence for reversing NPC radioresistance.

分割照射诱发的放疗抵抗是鼻咽癌复发、治疗失败的内在原因，但具体机制不明。我们前期研究提示：① EglN1与鼻咽癌不良预后呈负相关，放疗抵抗株中，EglN1表达下降；② EglN1或VHL敲除的细胞系，放射敏感性下降，Snail表达上升；③此外，鼻咽癌细胞内加入谷氨酸，其迁移、侵袭能力增加，细胞放射抗性增加。据此，我们推测：EglN1是调控放疗抵抗的关键分子；EglN1可能通过羟基化HIF1、磷酸化AKT、Snail，导致其被VHL识别降解以抑制放疗抵抗。谷氨酸抑制剂利鲁唑可能通过抑制胞外谷氨酸，增加xCT活性，进而增加胱氨酸进入细胞，减少EglN1的氧化失活，从而提高鼻咽癌放射敏感性。本项目拟以鼻咽癌组织标本、亲本细胞系、放疗抵抗细胞系为研究对象，应用CRISPR/Cas9、基因芯片、生物信息学软件分析等技术揭示谷氨酸/EglN1/ SNAIL信号通路参与放疗抵抗的具体机制。

分割照射诱发的放疗抵抗是鼻咽癌复发、治疗失败的内在原因，但具体机制不明。我们前期研究提示：①EGLN1与鼻咽癌不良预后呈负相关，放疗抵抗株中，EGLN1表达下降；②EGLN1或VHL敲除的细胞系，放射敏感性下降，Snail表达上升；③此外，鼻咽癌细胞内加入谷氨酸，其迁移、侵袭能力增加，细胞放射抗性增加。据此，我们推测：EGLN1是调控放疗抵抗的关键分子；EGLN1可能通过羟基化HIF1、磷酸化AKT、Snail，导致其被VHL识别降解以抑制放疗抵抗。谷氨酸抑制剂利鲁唑可能通过抑制胞外谷氨酸，增加xCT活性，进而增加胱氨酸进入细胞，减少EGLN1的氧化失活，从而提高鼻咽癌放射敏感性。本项目拟以鼻咽癌组织标本、亲本细胞系、放疗抵抗细胞系为研究对象，应用CRISPR/Cas9、基因芯片、生物信息学软件分析等技术揭示谷氨酸/EglN1/SNAIL信号通路参与放疗抵抗的具体机制。