Pygo2介导 Wnt信号的分子机理和在乳腺/乳腺癌干细胞增殖中的作用

项目名称： Pygo2介导 Wnt信号的分子机理和在乳腺/乳腺癌干细胞增殖中的作用

项目编号： No.30871279

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 李博安

作者单位： 厦门大学

项目金额： 30万元

中文摘要： Pygo2是新近发现的beta-catenin结合蛋白，然而在Wnt信号中的作用、下游分子机制以及生物学功能仍不十分清楚。 我们应用转基因和基因敲除小鼠技术研究了Pygo2在乳腺癌形成中的作用；用串联亲和层析（TAP）技术鉴定了Pygo2的下游结合蛋白，并研究其介导wnt信号的分子机制。发现Pygo2能够促进乳腺/乳腺癌干细胞的扩张性自我更新，增强wnt 信号的强度。我们进一步在乳腺癌细胞系中分离出Pygo2 N端结构域（NHD）的结合蛋白包括CDK8、RbBP5和GCN5，它们分别为中介因子复合体组分、组蛋白甲基化酶SET1-HMT、乙酰基转移酶STAGA-HAT等复合体的主要成份；进一步发现Pygo2 能够对小鼠以及人乳腺癌干细胞的维持产生重要影响。本课题运用转基因与基因敲除小鼠技术、干细胞操作技术与细胞生物学、分子生物学技术，详尽阐明了 Pygo2 在乳腺癌干细胞自我更新与增殖中的作用，并揭示这种作用的分子调控机理，为全面揭示乳腺癌的发病机制奠定了基础。

中文关键词： 中介因子;表观遗传;Wnt信号; 乳腺癌; 干细胞

英文摘要： Pygo2 is a newly found beta-catenin associated protein. However, the underlying molecular mechanism of Pygo2 in mediating wnt signaling as well as its biological function are largely obscure. We analyzed the biological function of Pygo2 in the formation of breast cancer by utilizing the transgenic and knockout mice models. In addition, we also studied the molecular mechanisms of Pygo2 in mediating wnt signaling using the TAP technique. Our results revealed that Pygo2 could enhance the expansive self-renewal ability of mouse and human mammary/breast cancer stem cells. In addation, Pygo2 was found to enhance the wnt activity in vtro and in vivo. Using TAP technique, we have identified several Pygo2 N terminal homolog domain (NHD) associated proteins,including CDK8, RbBP5 and GCN5, which belong to components of Mediator coplex,and SET1-HMT or STAGA-HAT complexes. Further study indicated that Pygo2 plays a critical role in mainteining self-renewal of mouse and human breast cancer stem cells. By using transgenic and knockout mice models, stem cell manupulation skill, and molecular and cellular biology techniques, we elucidate, in this project, the boilogical function of Pygop2 in the self-renewal of breast cancer stem cells, and unraveled the molecular mechanisms of Pygo2 in mediating wnt signaling. This study have provided important information for totally understanding of the pathogenesy of breast cancer.

英文关键词： Mediator; Epigenetics;Wnt signaling; breast cancer; stem cells