Fas通路通过调控MRP1表达促进大肠癌化疗耐药性的分子机制研究

Our previous study showed that Fas activation could promote ABC transporters expression, such as MRP1,and induce chemoresistance in colorectal cancer (CRC).According to these data and results from preliminary experiments, we hypothesized on one hand Fas activation can induce nuclear expression of c-Jun and SP1, then c-Jun binds with SP1, which promotes SP1 transcriptrional activity on MRP1 expression;on the other hand, Fas activation can inhibit miR-145 expression, leading to its binding with MRP1 and SP1 3’UTR to a lesser extent, and this event can finally promote MRP1 and SP1 translation.In this study,we will mainly investigates how Fas signaling regulates MRP1 expression through gene overexpression, RNAi, luciferace reporter assay, bioinformatics, analysis of clinical samples and animal studies. Meanwhile, we will elucidate the following points:1.the role of the molecules downstream of ERK1/2 MAPK(c-Jun, SP1 and miR-145) during Fas-induced MRP1 expression;2.the expression of the molecules downstream of ERK1/2 MAPK in clinical samples,and the ralationship between the molecules downstream of ERK1/2 MAPK and chemotherapy reponse or prognosis;3.whether the molecules downstream of ERK1/2 MAPK would be a therapeutic target during Fas-induced chemoresistance. The significance of this study can add new contents into the non-apoptosis effects of Fas signaling and provide new targets for diagnosis, therapy and prognosis in CRC.

前期研究证实Fas通路激活后诱导大肠癌细胞表达多种ATP结合运输蛋白，如MRP1，并使大肠癌细胞对多种化疗药物耐药。根据前期工作和预实验结果，我们推测：Fas通路激活ERK1/2后促进c-Jun和SP1在胞核内上调，两者结合后可增强SP1对MRP1的转录调控；此外，Fas通路激活ERK1/2后可抑制miR-145表达， miR-145与MRP1 、SP1 mRNA结合减少从而促进两者表达。本项目拟通过分子生物学、免疫学和动物实验等方法，深入探索Fas通路诱导MRP1表达的分子机制，并阐明：1. ERK1/2 下游调控相关分子在Fas通路诱导MRP1表达中的作用，以及其与患者化疗效果、预后的关系；2.ERK1/2下游调控相关分子可否作为体内治疗靶点抑制Fas通路诱导的大肠癌化疗耐药性。此次研究成果可进一步揭示Fas通路调控大肠癌化疗耐药性的分子机制，并为大肠癌的治疗和预后分析提供新的分子靶点

Fas/CD95 通路是一条重要的细胞凋亡通路，在维持机体免疫系统稳定和诱导肿瘤细胞凋亡的过程中具有重要作用。但是近年研究发现 Fas 通路可以诱导非凋亡效应从而促进肿瘤细胞增值、转移 以及分泌炎症因子(IL8,MCP-1)等。我们前期研究证实Fas通路激活后诱导大肠癌细胞表达多种ATP结合运输蛋白，如MRP1，并使大肠癌细胞对多种化疗药物耐药。本项目拟通过分子生物学、免疫学和动物实验等方法，深入探索Fas通路诱导MRP1表达的分子机制，并阐明：1.ERK1/2下游调控相关分子在Fas通路诱导MRP1表达中的作用，以及其与患者化疗效果、预后的关系；2.ERK1/2下游调控相关分子可否作为体内治疗靶点抑制Fas通路诱导的大肠癌化疗耐药性。目前，我们初步证实：Fas通路激活ERK1/2后促进c-Jun和SP1在胞核内上调，两者结合后可增强SP1对MRP1的转录调控；此外，Fas通路激活ERK1/2后可抑制miR-145表达， miR-145与MRP1 、SP1 mRNA结合减少从而促进两者表达。此次研究成果可进一步揭示Fas通路调控大肠癌化疗耐药性的分子机制，并为大肠癌的治疗和预后分析提供新的分子靶点。