HNF3β介导的肠道巨噬细胞活化调控在炎症性肠病炎症-肿瘤恶性转化过程中的作用和机制研究

Inflammatory bowel disease was closely associated with colorectal carcinoma and it was the major and cutting-edge scientific problems in the field of inflammatory bowel disease (IBD)-associated colorectal cancer. Bowel macrophages activation and inflammatory cytokine production played important roles in IBD-related colorectal carcinoma carcinogenesis and the molecular mechanisms have attracted much attention . We previously reported the roles of HNF family member HNF4α in intentinal cancer aggravation (Mol Carcinogen). However, the roles of HNF family members in IBD- associated colorectal cancer have not been well characterized..Here we systematically examined the expression of HNF family members in bowel macrophages of AOM/DSS-induced colorectal cancer, and found that HNF 3β expression was significantly decreased. We therefore constructed the conditional macrophage-specific HNF3βknockout mouse and found that the deficiency of HNF3β significantly promoted the development of the colorectal cancer in the AOM/DSS-induced colorectal cancer mouse model. Hence, this project intends to study the roles of HNF 3β in the regulation of intestinal macrophage activationand IBD-associated colorectal cancer carcinogenesis . These results might provide theoretical basis and research foundation for HNF3β becoming a new intervention therapeutic targets for colorectal carcinoma.

炎症性肠病与结直肠癌的发生密切相关，是炎症性肠病相关结直肠癌发生研究领域中的重大科学问题。肠道巨噬细胞活化和炎症因子表达在炎症性肠病炎症-肿瘤恶性转化过程中具有重要作用，其活化的调控机制目前受广泛关注。申请人前期对HNF家族分子HNF4α在结肠癌恶性进展过程中的作用进行了深入研究，结果发表于Mol Carcinogen（IF4.77）。但是，目前仍缺乏HNF家族分子在肠道炎症和肿瘤发生中的系统研究。我们在AOM/DSS小鼠自发结肠癌模型中，系统筛选HNF家族分子在肠道巨噬细胞中的表达，发现HNF 3β表达显著降低。我们因而构建了HNF3β巨噬细胞敲除小鼠，利用AOM/DSS诱导结直肠癌，结果发现巨噬细胞敲除HNF 3β能够显著促进结直肠癌的发生。据此本项目拟研究HNF 3β在肠道巨噬细胞活化及其介导的炎症性肠病相关结直肠癌发生发展中的作用，为寻求新的结肠癌干预靶点提供理论依据和研究基础。

慢性炎症造成的炎症反应的异常活化以及炎症细胞的持续性激活是癌症发生的重要驱动力，长期慢性炎症是结肠癌恶性转化的重要机制。炎症性肠病与结肠癌的发生密切相关。其中，肠道巨噬细胞的异常活化是结肠炎症导致癌性转化的中心环节。本项目聚焦肝细胞核因子3β在结肠癌变中的作用及相关机制开展了一系列研究。首先，我们证实肝细胞核因子3β在结肠癌中发挥抑癌基因的作用，在结肠癌中低表达，并且结肠癌恶性程度越高，肝细胞核因子3β表达越低。肝细胞核因子3β的低表达与结肠癌侵袭深度及淋巴结转移密切相关。其次，我们证实肝细胞核因子3β过表达能够逆转结肠癌细胞恶性表型。在结肠癌细胞中，将肝细胞核因子3β过表达，我们观察到细胞增殖、侵袭、迁移能力显著下降，在动物实验水平，上调肝细胞核因子3β的表达水平同样能够抑制裸鼠体外成瘤的能力。第三，肝细胞核因子3β表达水平的下调与炎症信号通路相关分子激活相关。我们敲除肝细胞核因子3β在小鼠体内的表达，分离肠道巨噬细胞，用蛋白质谱筛选炎症信号通路相关分子，发现DDX18、STAT3、DDX6、S100A9、TLR4、S100A8、DDX3、DDX21、DDX15、S100A11、OCIAD2、TP53、SOX9、JAK1等分子表达显著升高。最后，我们选取20例人结肠癌组织标本，进行蛋白质组学分析，结果发现差异表达的蛋白分子能够分为3个亚型，其中一型预后极差，与炎症反应的激活密切相关。本项目研究揭示了结肠癌炎癌转化的相关分子机制，为提出结肠癌新的分子干预靶点提供了理论基础。