外泌蛋白CTHRC1介导的肿瘤基质免疫重塑与卵巢癌侵袭转移机制的研究

Ovarian cancer is more likely to metastasis at a very early stage, but the mechanism is still not clear. As well known, TAMs and TAFs are two important stromal cells in the stromal microenvironment which related to tumor invasion and metastasis. Previously, we discovered collagen triple helix repeat containing-1 (CTHRC1) expression was up-regulated in the stroma of epithelial ovarian cancer (EOC) tissues, surrounding by enriched M2 type-tumor associated macrophage (TAMs) and immune factors secreted by tumor associated fibroblasts (TAFs). In this study, we intend to fully investigate the biological characteristics of CTHRC1 in vitro and in vivo using ovarian cancer cell lines, TAMs, TAFs, SCID mouse and EOC patients as models, and obtain evidence of direct causal relationship between the immune regulation in tumor stroma microenvironment and the metastasis of EOC. Further steps are designed to clarify the mechanism that CTHRC1 mediated PI3K/Akt and JAK/STAT signaling pathway in the tumor immune matrix remodeling, including immune active factors releasing, TAMs-M1/M2 type and CD3+ CD8+ T cell activation and its relationship with metastasis of EOC. A complete comprehensive knowledge of characteristics of CTHRC1 in EOC would help better understand the pathogenesis of EOC and resolve practical problems regarding to diagnosis, treatment, and follow-up, thus provide great values in clinical application, especially in immune therapy.

卵巢癌早期就易发生侵袭转移，已知肿瘤相关巨噬细胞（TAMs）和肿瘤相关成纤维细胞（TAFs）是基质微环境中与肿瘤侵袭转移密切相关的两大类基质细胞，我们前期发现卵巢癌细胞外分泌蛋白CTHRC1主要分布于转移灶基质中，其周围富集M2型TAMs分布及TAFs分泌的免疫因子，提示外泌蛋白CTHRC1作为卵巢癌细胞与基质细胞间的“媒介桥梁”促进肿瘤转移。本课题将进一步从癌细胞与基质细胞之间免疫调控的角度，以卵巢癌细胞、TAFs、TAMs、免疫系统人源化SCID小鼠、卵巢癌患者为研究对象，体内、外实验系统探讨以CTHRC1介导的PI3K/Akt及JAK/STAT信号通路在肿瘤基质免疫重塑（免疫活性因子、TAMs-M1/M2分型及CD3+CD8+T细胞激活）与卵巢癌侵袭转移的关系及相关机制，为寻找新型免疫治疗的靶点分子及卵巢癌诊断与治疗的靶标提供理论基础。

上皮性卵巢癌是女性最常见的恶性肿瘤之一，疾病早期就容易发生侵袭和远处转移，其病死率一直居妇癌之首，而转移是其主要致死原因，但是目前有关卵巢癌的转移机制尚不明确。本课题对卵巢癌细胞与包括TAFs和TAMs在内的肿瘤微环境基质细胞之间通过外泌蛋白CTHRC1对其免疫重塑调节与卵巢癌侵袭转移的关系及机制进行了深入探讨。我们首次发现外泌蛋白CTHRC1可以通过Integrinβ3/Akt信号通路上调巨噬细胞中趋化因子受体CX3CR1的表达，促进肿瘤相关巨噬细胞的极化、招募和迁移，继而活化M2型巨噬细胞进一步促进卵巢癌细胞的体外侵袭和转移能力。同期我们也首次证实CTHRC1可促使卵巢癌微环境中肿瘤相关成纤维细胞活化并优势表达RNA结合蛋白MEX3A，同时MEX3A通过与PABPC1蛋白结合参与调控微环境中CD8+ T 淋巴细胞, 树突状细胞（dendritic cells）和巨噬细胞以及免疫调节因子包括IL10RB、IDO1、VTCN1、HAVCR2、C10orf54、 TNFRSF18、TNFRSF14和TNFRSF13C的表达，参与免疫微环境调控。在临床组织标本中，我们发现卵巢癌组织中CTHRC1的表达水平与FIGO临床分期、淋巴结转移、远处转移、有无腹水癌细胞等密切相关，将以上临床病理特征纳入多因素回归分析，结果显示CTHRC1的表达水平（P=0.016，OR=3.661）能够作为卵巢癌转移的独立预后因素。进一步通过通过小鼠转移前微环境模型，RNA-seq方法筛选CTHRC1调控卵巢癌腹腔转移前微环境相关的差异基因，深入探讨了CTHRC1促进肿瘤微环境炎症-免疫-代谢调控网络与卵巢癌转移的分子机制，同时提出籍由针对CTHRC1 激活PI3K及AMPK信号通路的靶点分子将有助于开发出新型抗肿瘤免疫治疗新药。