肾癌中KLF4转录调控细胞外基质蛋白fibulin-1的分子机制研究

As the important component of tumor-related microenvironment, extracellular matrix (ECM) plays important role in the tumorigenesis and progression. However, the interation between ECM and tumor cell need further understanding. Our previous study found that the transcription factor KLF4 and ECM protein fibulin-1 were specifically downregulated and act as tumor suppressor in renal cell carcinoma (RCC), but whether there was relationship between these two genes remains unknown. Our further experiment showed there was positive correlation between KLF4 and fibulin-1 expression in RCC samples and KLF4 overexpression significantly induced fibulin-1 upregulation in RCC cell lines. Furthermore, multiple KLF4 binding sequences were found in FBLN1 promoter region. All these observations implied that KLF4 might function in RCC through transcriptional regulating fibulin-1. So in this project, we plan to fully study the interaction between KLF4 and fibulin-1, and investigate the molecular mechanism of this transcriptional regulation as well as the infuence on RCC cell functions to further reveal the interaction between the ECM and RCC cells.

作为肿瘤微环境的重要组成，细胞外基质在肿瘤的发生、发展过程中发挥着重要的功能，然而它与肿瘤细胞之间如何相互作用还有待深入研究。我们之前分别报道过转录因子KLF4及细胞外基质蛋白fibulin-1在肾癌组织中特异性表达减低并发挥重要的抑癌功能，但它们之间是否存在关联还未见报道。我们的后续实验发现KLF4与fibulin-1在肾癌组织中表达呈正相关，肾癌细胞中过表达KLF4引起fibulin-1的显著上调，且fibulin-1的启动子区存在多个KLF4转录因子结合位点，提示KLF4可能作为转录因子调控fibulin-1的表达从而影响肾癌细胞的相关功能。本研究拟通过深入验证肾癌中KLF4对fibulin-1的调控作用，阐明KLF4调控fibulin-1表达的分子机制，进而研究KLF4调控fibulin-1对肾癌细胞功能的影响，为深入理解肾癌细胞与细胞外基质间的相互作用提供基础。

我们之前分别报道过转录因子KLF4及细胞外基质蛋白fibulin-1在肾癌组织中特异性表达减低并发挥重要的抑癌功能，但它们之间是否存在关联还未见报道。本项目围绕肾癌中KLF4 与fibulin-1 之间的相互作用关系，综合运用分子生物学、生物信息学、细胞生物学、统计学等方法，验证肾癌中KLF4对fibulin-1 的调控作用，阐明KLF4 调控fibulin-1 表达的分子机制，进而研究KLF4 调控fibulin-1 参与肾癌细胞功能的分子机理。通过本项目的实施，我们分别在肾癌组织标本及细胞系中证实KLF4调控fibulin-1的表达，进一步的研究表明KLF4作为转录因子通过结合fibulin-1启动子区-360~-370区域调控fibulin-1的转录，并在细胞及动物水平证实fibulin-1参与了KLF4介导的抑癌效应。本研究系统阐明了肾癌中KLF4调控fibulin-1表达的分子机制，进而揭示了KLF4调控fibulin-1对肾癌细胞功能的影响，这将有助于我们进一步理解肿瘤细胞与细胞外基质间的相互作用，从而丰富肾癌相关分子生物学理论，并可能为肾癌的临床治疗提供新的策略和作用靶点。