β-catenin下游调控相关分子在Fas信号通路诱导大肠癌干细胞特性中的作用机制研究

Our previous study showed that Fas activation could promote EMT and metastasis in colorectal cancer(CRC) through nuclear expression of β-catenin that induces expression of EMT molecules. According to these data and results from preliminary experiments, we hypothesized nuclear expression of β-catenin can induce stemness in CRC through induction of Bmi1 that is inhibited by miR-183 and miR-200c, both of which can be depressed by Zeb1 that is directly induced by β-catenin. This study mainly investigates the role of β-catenin-modulated molecules during Fas-induced stemness in CRC through gene expression, RNAi, stem cell assay, bioinformatics and in vivo studies. The preliminary mechanism that Fas-induced stemness in CRC will be elucidated. Meanwhile, β-catenin-modulated molecules will be identified as the important targets that can inhibit Fas-induced stemness. The significance of this study can add new content into the non-apoptosis effects of Fas signaling and provide new targets for diagnosis, therapy and prognosis in CRC.

我们前期研究证实：Fas通路激活后可引起β-catenin在细胞核内上调，诱导相关EMT分子表达，从而使大肠癌细胞发生EMT和转移。根据前期工作和预实验结果，我们推测：β-catenin进入细胞核后诱导下游的Zeb1表达， Zeb1同时抑制miR-183和miR-200c的表达，两者下调可促进干细胞转录因子Bmi1上调，从而诱导大肠癌干细胞特性。本项目拟通过基因过表达和RNA干扰、干细胞诱导实验、生物信息学分析和动物实验等方法深入探索β-catenin下游调控相关分子在Fas通路诱导大肠癌干细胞特性中的作用机制，初步阐明Fas通路诱导大肠癌干细胞特性的分子机制，明确β-catenin下游调控相关分子是阻断Fas通路诱导大肠癌干细胞特性的重要靶点。此次研究成果可进一步补充Fas通路的非凋亡功能，并为大肠癌的诊断标记物、治疗和预后分析提供新的分子靶点。

我们前期研究证实：Fas通路激活后可引起β-catenin在细胞核内上调，诱导相关EMT分子表达，从而使大肠癌细胞发生EMT和转移。根据前期工作和预实验结果，我们推测：β-catenin进入细胞核后诱导下游的Zeb1表达， Zeb1同时抑制miR-183和miR-200c的表达，两者下调可促进干细胞转录因子Bmi1上调，从而诱导大肠癌干细胞特性。本项目通过基因过表达和RNA干扰、干细胞诱导实验、生物信息学分析和动物实验等方法深入探索β-catenin下游调控相关分子在Fas通路诱导大肠癌干细胞特性中的作用机制，并探索：（1）Fas通路对大肠癌干细胞特性的影响；（2）β-catenin下游调控相关分子（Zeb1、miR-200c、miR-183和Bmi1）在Fas通路诱导的大肠癌干细胞特性中的作用机制；（3）β-catenin下游调控相关分子可否作为体内治疗靶点抑制Fas通路诱导的大肠癌干细胞特性。现基本阐明： Fas通路激活后，ERK1/2 MAPK 抑制GSK-3β活性, 从而促进β-catenin进入细胞核内，并促进ZEB1表达，ZEB1通过与miR-200c启动子结合从而抑制其表达， miR-200c表达下调后，减少与Bmi1 3’UTR结合，从而增强其表达，最终诱导干细胞特性。此次研究成果可进一步补充Fas通路的非凋亡功能，并为大肠癌的诊断标记物、治疗和预后分析提供新的分子靶点。