IKKβ-ARID1A途径的确立及其在宫颈癌Hedgehog信号通路激活中的作用及机制研究

Evidences have shown that loss of ARID1A protein expression in the cervical cancer is related to malignant progression of the cancer.But the molecular mechanism involved in ARID1A expression deletion and its tumor suppressor function remain to be elucidated. Previously we found that IKKβ interacts with ARID1A and inhibits the expression of ARID1A at post-transcription level. Moreover, we found that ARID1A binds to the promoter of SUFU and inhibits the transcription of SUFU. In this study, we will further explore that ARID1A is phosphorylated by IKKβ and subsequently degraded by βTRCP mediated Ubiquitination,which may be a important mechanism of ARID1A loss in the cervical cancer. We will investigate that ARID1A suppresses Hedgehog pathway by upregulating SUFU expression through SWI/SNF mediated chromatin remodelling activity which is a improtant mechanism of ARID1A tumor suppressor function. We will also prove that TNFα crosstalks with Hedgehog pathway through TNFα/IKKβ/ARID1A/SUFU/Hh pathway. This study will help to discover new promising therapeutic approach for the treatment of cervical cancer.

研究资料显示抑癌基因ARID1A在宫颈癌中表达缺失，且其功能缺失与宫颈癌恶性进展相关，但其在宫颈癌中表达缺失及抑癌机制尚不清楚。本项目前期研究发现在宫颈癌细胞中IKKβ与ARID1A有相互作用并在转录后水平抑制ARID1A表达；ARID1A结合在SUFU启动子并上调其转录。本项目拟在此基础上从分子、细胞、组织和动物水平：阐明IKKβ磷酸化ARID1A以及βTRCP介导的ARID1A泛素化降解是宫颈癌中ARID1A表达缺失的重要机制之一；确定ARID1A通过SWI/SNF染色质重塑活性上调SUFU表达来抑制Hedgehog通路是ARID1A抑制宫颈癌发生发展的机制之一；阐明TNFα和Hedgehog通路在宫颈癌中通过TNFα/IKKβ/ARID1A/SUFU/Hh这条新通路来交叉调控，共同促进宫颈癌恶性进展。以上问题的解决，将为宫颈癌的诊断和发现治疗性靶标提供理论基础和实验依据。

宫颈癌是妇科常见肿瘤，严重影响妇女身心健康，但其发病机制尚不十分清楚。通过对现有的TGCA宫颈癌数据库分析发现，ARID1A在宫颈癌中存在高频缺失，表明其在宫颈癌发生发展中起重要作用，但在宫颈癌中调控ARID1A功能的分子机制以及其下游的促癌分子网络尚未完全阐明。我们前期研究发现在宫颈癌细胞中IKKβ与ARID1A能相互结合并在翻译后水平抑制ARID1A表达；通过ChIP-seq检测发现ARID1A结合在SUFU启动子并上调其转录。在此基础上，本项目在宫颈癌组织中发现IKKβ和ARID1A分别显著上调和下调，并且两者在癌组织中呈现显著的负相关性；IKKβ和ARID1A在癌组织中的变化与患者的临床分期、局部浸润和生存期显著相关。在分子和细胞水平证实IKKβ能磷酸化ARID1A进而促进ARID1A与β-TRCP的结合，从而导致ARID1A的泛素化和降解。本项目也从分子、细胞和组织水平证实了ARID1A通过介导SWI/SNF复合物结合SUFU启动子从而上调SUFU表达，进而抑制宫颈癌Hedgehog通路的激活。通过本项目的研究我们发现了宫颈癌中ARID1A功能的调控机制和ARID1A抑制宫颈癌的分子机理，这为治疗宫颈癌、预防其转移和复发提供了新的靶点。