卵巢癌自噬现象对化疗后免疫窗口期抗肿瘤CD8+CD45RO+T细胞生成调控作用的研究

During the post-chemotherapeutic "immune window" period, the proportion of anticancer CD8+CD45RO+ T cells often increases significantly in the peripheral blood of ovarian cancer patients, which refects the immune reconstruction process of anticancer memory T cell colonies in the body. As an important anticancer immunological mechanism, this process is tightly associated with the chemotherapeutic agent-induced apoptosis of ovarian cancer cells, the phagocytosis of dead cancer cells and the presentation of tumor antigens/peptides by dendritic cells. Recently, more and more studies indicated that chemotherapeutic agent-induced autophagy of cancer cells plays a role in the formation of anticancer immune memory system. However, researchers have quite different views on this topic, none of which can be supported by the convincing clinical or experimental evidence. We expect to quantitatively characterize the relationship between the autophagy phenomenon of ovarian cancer and the formation/maintenance of the peripheral anticancer CD8+ memory T cells from three research levels: clinical investigation, animal model and in vitro experiment. We intend to define the different regulatory effects exerted on the construction of bodily anticancer immune memory system by different autophagic levels, antophagy/apoptosis ratios and their association with the drug-resistance property and anti-T cell ability of ovarian cancer cells. We also plan to explore the internal molecular mechanisms which influence the biological processes of the autophagy-related DC and T cell maturation in the bodily anticancer immune system. The obtained research results would form the basis for the future application of the autophagy regulators, immunoadjuvants and CD8+CD45RO+ T cell-based adoptive immunotherapy in the clinic.

卵巢癌患者化疗后"免疫窗口期"内，外周血中抗肿瘤CD8+CD45RO+T细胞比例显著上升，反映了体内免疫记忆T细胞群落的重建过程。这种抗肿瘤免疫机制与化疗药物对癌细胞的杀伤，以及凋亡癌细胞被树突状细胞吞噬，肿瘤相关抗原多肽被提呈有密切关系。近期，越来越多研究表明，癌细胞自噬参与了这一抗肿瘤免疫记忆体系的形成。然而，各种学术观点相互矛盾，缺少足够临床和实验证据支持。我们拟从临床病例调查、动物模型和体外实验三个层次入手，对卵巢癌自噬现象与外周血抗肿瘤CD8+CD45RO+T细胞生成/维持关系进行定性定量研究，确定不同自噬水平、自噬/凋亡比例、癌细胞耐药特性、癌细胞抗T细胞能力对于体内抗肿瘤免疫记忆建立的调控作用，阐明其中相关的作用机制，为今后临床使用自噬调节剂、免疫促进剂和CD8+CD45RO+T细胞过继免疫治疗提供理论和临床前期研究基础。

本研究项目原拟通过回顾性队列研究、免疫组化、动物模型以及转录调控等分子生物学实验方法明确卵巢癌自噬水平及相关调控因素对于“免疫窗口期”外周血抗肿瘤CD8+CD45RO+ T细胞生成水平的影响。为此，我们深入细致地从患者标本、卵巢癌动物和细胞模型以及基因转录调控机制等多方面对化疗诱导性自噬如何影响卵巢癌细胞的免疫调控因子释放、外周血T细胞如何对应答并最终影响患者预后结局进行了探索和分析。通过四年工作，已经成功地证明了以下科学事实：第一：卵巢癌化疗后产生的自噬应答可以显著影响其外泌性免疫调节蛋白的表达，如：GDF15和PSG3等。其中，自噬诱导GDF15水平影响了患者预后。第二：卵巢癌自噬对于其自身GDF15分泌表达水平的影响是化疗强度依赖性、存在细胞个体化差异以及促GDF15表达/分泌作用相互分离的。第三：GDF15除了抑制单核-巨噬细胞针对内源性抗原（比如肿瘤抗原）免疫应答反应外，还可以抑制树突状细胞的分化和成熟。从而干扰和抑制抗肿瘤CD8+CD45RO+ T细胞的生成。由此，我们在国际上首次证明疗诱导性自噬可以影响“免疫窗口期”外周血抗肿瘤CD8+CD45RO+ T细胞生成水平，导致Treg/CTL细胞比例改变，影响患者预后。我们也首次证明，GDF15是介导此效应的一种重要细胞因子，其表达量受到自噬相关p53和/或HBP1信号路径的调控。上述研究成果已经发表SCI论文6篇，总影响因子24.6。我们在卵巢癌自噬相关肿瘤免疫问题上已达到国际先进水平，得到很多知名学者关注。