肝癌EMT中KLF8蛋白上下游调控信号的深入机制研究

Krüppel-like factor 8 (KLF8) has been known to be a target gene and an activator of Wnt/β-catenin signaling pathway, which changes the epithelial mesenchymal transition (EMT) status of affected cells. Our previous studies have indicated an elevated expression of KLF8 intissue specimens of hepatocellular carcinoma, which is associated with the disorders in Wnt/β-catenin signaling pathway. Further studies have found the molecular mechanism of the abnormal status of KLF8 in HCC and its regulatory role with Wnt/β-catenin signaling remain obscured. The preliminary aim of our present research is to investigate the mechanism of abnormally highexpression of KLF8 as well as changes in its protein modification and intracellular location. Furthermore, we intend to clarify the role of KLF8 in the EMT status in HCC by changes in molecular markers and transcription complex, as well as DNA arrays in the regulatory area on its binding site. Thirdly, we will further explore the DNA arrays and reporting genes of Wnt/β-catenin signaling pathway on KLF8 binding sites. Generally, the study as a whole would deepen the understanding of the effects on KLF8 on HCC,thus evaluating its potential to be a target factor for the early diagnosis and targeted drug therapies of HCC.

KLF8是Wnt/β-catenin信号靶基因，而KLF8也能激活Wnt/β-catenin信号通路，改变细胞上皮间质转型（EMT）。我们前期研究发现KLF8在肝癌组织和细胞中高表达，与Wnt/β-catenin信号失调相关，然而KLF8异常的原因及KLF8与Wnt/β-catenin相互调控的具体方式尚不清楚。本项研究将通过对KLF8异常高表达、蛋白修饰异常和胞内定位变化的分析，明确其分子机制；通过研究KLF8对肝癌EMT状态改变、EMT分子标志表达变化及KLF8转录复合体及所结合基因调控区的DNA序列分析，阐明KLF8改变EMT的机制；通过研究Wnt/β-catenin信号转录因子在KLF8基因调控区的结合位点序列及报告基因实验，明确其调控KLF8的深入机制。由此，将更加深入理解KLF8在肝癌发生发展中的作用机制，为KLF8蛋白作为肝癌早期诊断和靶向药物开发目标分子建立理论基础。

肝细胞癌（HCC）是最常见的原发性肝癌，也是癌症死亡的第三大原因。 Krüppel样因子8（KLF8）是一种致癌基因，并已报道在HCC中发挥重要作用，但其主要涉及的信号传导途径处于未知。在本项目中，课题组系统地分析了KLF8在HCC中的作用，使用RNA测序和抗H3K27乙酰化ChIP测序，结合生物信息学分析以及数据挖掘手段对结果进行阐释。本研究结果表明KLF8在HCC中起转录抑制因子的作用，主要调控凋亡相关基因。此外，课题组通过ChIP实验验证了KLF8与预测的部分靶基因的组合，这支持了我们分析的有效性。最终，课题组证明了两个预测的靶标HMGA2和MMP7，是KLF8介导的HCC中抗凋亡作用的重要参与者。课题组的研究首次提供了KLF8在HCC中的作用的全景视图，并通过KLF8促进了HCC新目标的发现。