恶性腹水EVs通过调控卵巢癌细胞lnc-EUR/LGALS9促进CD8+T耗竭的作用和机制研究

高级别浆液性卵巢癌（HGSOC）是死亡率最高的一种女性生殖器官肿瘤。化疗耐药后HGSOC，PD-1单药免疫治疗有效率仅8%左右，提示其存在免疫治疗抵抗。申请人前期发现铂耐药患者PD-1+、Tim-3+耗竭CD8+T比例较敏感组升高。Microarray结果显示铂类耐药HGSOC恶性腹水来源的胞外囊泡与敏感组相比，可以诱导卵巢癌lnc-EUR和LGALS9的上升。且lnc-EUR的敲除可以抑制LGALS9表达并促进共培养体系中CD8+T细胞活化。提示耐药HGSOC腹水可能通过lnc-EUR/LGALS9介导肿瘤免疫逃逸。本项目拟利用RNA pull-down、质谱等技术，从细胞、动物模型、HGSOC患者三个层面，研究腹水胞外囊泡通过lnc-EUR/LGALS9介导肿瘤免疫逃逸和CD8+T耗竭的分子机制，揭示化疗耐药后免疫治疗抵抗的原因，为铂类耐药卵巢癌患者提供新的免疫或化疗联合免疫治疗策略。

High grade serous ovarian cancer (HGSOC) is a kind of female genital tumor with the highest mortality. PD-1 or other single drug immunotherapy effective rate is only about 8% in plasitin resistant HGSOC, suggesting that there exsits immunotherapy resistance mechanisms. From our previously data, the proportion of PD-1 + and Tim-3 + CD8 T in chemoresistant patients were higher than those in the sensitive group, and the extracellular vesicles (EVs) from malignant ascites of chemo-resistant HGSOC patients could induce the increase of lnc-EUR in SKOV3, and then up regulate the expression of LGALS9. The knockdown of lnc-EUR can abrogate the exhausition of CD8 + T cell through inhibiting LGALS9. These results suggest that EVs derived from plastin resistant HGSOC ascites may participate in the resistance of immunotherapy of ovarian cancer through lnc-EUR/LGALS9. RNA-seq, RIP, RNA Pull-down, RIP, mass spectrometry and other technologies will be used to study how ascites extracellular vesicles promote CD8 + T exhausition and immune escape by regulating lnc-EUR/LGALS9 from three levels of cell, animal model and HGSOC patients. Finally, based on the mechanism of lnc-EUR regulating LGALS9, the reason of resistance of platin resistant patients to immunotherapy mediated by ascites will be elaborated, which will provide new immunotherapy or chemotherapy combined immunotherapy strategies for platinum resistant HGSOC patients.