肝癌免疫微环境调变肿瘤干细胞作为转移复发防治新策略的基础研究

Cancer stem cells (CSC) are the “seeds” initiating metastasis/recurrence in cancers. Tumor microenvironment provides a niche for CSC sustainence. Currently, most CSC study focused on the intrinsic molecular mechanism and biological behavior itself, neglecting the critical impact of tumor microenvironment on the stemness maintence of CSC and its invasion and metastasis ability. Investigating the crosstalk between CSC and microenvironment may facilitate discovery of novel mechanisms of cancer metastasis and recurrence. This project will focus on several stromal cells especially immune cells in hepatocellular carcinoma (HCC) microenvironment to investigate that how tumor infiltrating immune cells regulate CSC’s stemness properties and metastatic ability, revealing the underlying molecular mechanism. Using secretome detection technologies, screening the secreting factors in peripheral blood which regulate the functions of circulating cancer stem cell (CCSC), and delineating the underlying molecular mechanism. Elucidate the vital role and molecular mechanism of bone marrow derived cells (BMDCs) in the lung metastasis process mediated by CSC and the formation of pre-metastatic niche. This study will reveal the role and mechanism of crosstalk between CSC and microenvironment in the process of metastasis/recurrence in HCC, establish the theory and experiment foundations for immune microenvironment promoted metastasis. This study may offer new intervention strategies and therapeutic target for preventing metastasis and recurrence in HCC.

作为“种子”细胞，肿瘤干细胞（CSC）在转移复发中扮演重要角色；肿瘤免疫微环境则为CSC提供良好生长环境，两者关系密切。当前CSC研究多着重于其本身，忽视肿瘤免疫微环境在其生存调控、表型维持和分化等方面的重要作用。免疫微环境和CSC作为整体进行研究有利于转移复发新机制及其防治新策略的发现。本项目在大量前期工作基础上，建立共培养体系，探讨肝癌浸润免疫细胞对CSC干性维持和促转移的作用及机制；利用分泌蛋白组学技术，筛选外周循环中调控循环肿瘤干细胞（CCSC）的免疫微环境分泌蛋白，研究其在循环系统内对CCSC功能和转移能力的影响和机制。进一步利用动物模型，阐明髓源性细胞在肝癌CSC肺转移及预转移小巢形成中的重要作用及机制。本研究将揭示肝癌免疫微环境调变CSC生物功能在肝癌转移复发中的作用和相关机制，奠定通过遏制促CSC免疫微环境进而抑制转移复发的理论和实验基础，为肝癌转移复发防治提供新思路和新靶

肿瘤转移离不开“种子”【肿瘤干细胞（Cancer stem cell，CSC）】和“土壤”（微环境）的相互作用。正确认识和把握肝癌CSC与免疫微环境相互作用的实质和关键，对于准确认识肝癌发生、发展和转移复发的全过程，了解肝癌转移复发的客观规律，具有极其重要意义。本项目建立初发肝癌和早期复发肝癌队列的多组学数据集，通过单细胞组学技术描绘早期复发肝癌和原发肝癌的浸润免疫微生态的全景图谱，发现并鉴定复发肝癌特征性CD8+ T细胞的免疫表型和功能状态，解析早期复发肝癌内的肿瘤细胞免疫表型和肿瘤-免疫细胞互作机制。本项目通过单细胞测序和质谱流式证实肝癌干细胞的异质性，描绘各CSC各亚群的特征。本项目提示免疫检查点蛋白可介导肝癌干细胞干性的耐药及免疫逃逸功能。此外，本项目发现循环免疫细胞也参与调变肿瘤干细胞，循环肿瘤干细胞（Circulating cancer stem cell, CCSC）的转录表达水平随血液循环发生动态变化，CCL5在CCSC的免疫逃逸中发挥重要，从肝静脉至外周动脉，CCSC的CCL5的过表达受到p38-MAX信号的转录调控，继而通过募集Tregs促进CCSC的免疫逃逸和播散。本项目对于抑制肝癌复发转移提供了多个潜在治疗靶点和策略。