YAP与突变p53在结肠癌上皮-间质转化中的作用机制研究

EMT is one of the most important reasons for the invasion and metastasis of colon cancer. Bioinformatics analysis and literature reports show that YAP as a transcription coactivator interacting with different transcription factors to regulate the downstream target genes is closely related with colon cancer invasion and metastasis. We found that upregulation of YAP expression played a role in EMT in colorectal cancer with increased cell migration ability and decreased expression of E-cadherin in colorectal cancer with p53 mutation. It was also found that YAP could interact with mutant p53, but could not regulate its expression. These results are consistent with the report that YAP physically interacts with mutant p53 in breast cancer and potentiates their pro-proliferative transcriptional activity. In summary, we speculate that YAP and mutant p53 act synergistically to regulate EMT in colon cancer. The aim of this study is to determine whether YAP regulates colorectal cancer EMT by interacting with mutant p53, the molecular basis of the interaction between YAP and mutant p53, and the mechanism of regulating EMT in colon cancer. This project will help to further understand the molecular mechanism of colorectal cancer EMT, providing a clue to the prediction of clinical outcomes and the search for new therapeutic targets.

EMT是结肠癌侵袭转移的重要原因之一。生物信息学分析和文献报道均提示YAP作为转录共激活因子通过与不同的转录因子相互作用调控下游靶基因，与结肠癌的侵袭转移密切关系。本项目前期结果证明在p53突变的结肠癌中，YAP表达增高细胞迁移能力增加，同时E-cadherin表达下降，提示YAP在p53突变的结肠癌EMT中有作用。同时发现YAP不能调控突变p53的表达水平，但可以与突变p53相互作用。这与文献报道乳腺癌中YAP可与突变p53作用促进细胞增殖一致。综上，我们推测YAP与突变p53共同作用调控结肠癌EMT。本项目拟研究明确YAP是否通过与突变p53相互作用调控了结肠癌EMT；揭示YAP与突变p53相互作用的分子基础及调控结肠癌EMT的作用机制。此项目有助于进一步了解结肠癌EMT的分子机制，为临床治疗效果的预判与新治疗靶点的寻找提供线索。

EMT是结肠癌侵袭转移的重要原因之一。生物信息学分析和文献报道均提示YAP作为转录共激活因子通过与不同的转录因子相互作用调控下游靶基因，与结肠癌的侵袭转移密切关系。我们的研究发现：YAP在结肠癌组织中表达明显高于癌旁组织。在结肠癌细胞中YAP可以明显增强细胞的迁移和侵袭能力。在调控EMT方面我们发现在结肠癌细胞中YAP可以明显抑制E-cadherin的表达并上调Slug的表达。进一步的机制探索中，我们在高表达YAP的结肠癌细胞中敲低Slug，在敲低YAP的结肠癌细胞中过表达Slug，我们发现YAP是通过上调Slug来抑制E-cadherin的表达的。通过Chip-qPCR和Luciferase报告基因实验，我们发现YAP可以增强Slug的转录活性。因此我们得到初步结论：YAP是通过增强Slug的转录活性，上调其表达，高表达的Slug可以作为转录抑制因子抑制了E-cadherin的表达，从而促进结肠癌EMT的发生。在项目执行过程中，我们再次证明了YAP作为转录共激活因子可以明显地促进结肠癌细胞的增殖，但是在正常培养的结肠癌细胞过程中YAP又具有明显地抑制结肠癌自噬的作用。进一步研究发现，YAP是通过与转录因子TEAD的结合增强了Bcl-2的转录活性，上调了Bcl-2的表达从而抑制了结肠癌细胞的自噬。我们的研究明确了YAP促进结肠癌EMT的可能的分子机制，同时初步证明了YAP可以通过抑制结肠癌细胞自噬性死亡促进细胞的增殖。后续我们会继续深入探讨YAP在调控细胞自噬性死亡与细胞增殖之间的交互作用机制。本项目进一步深入了解了YAP在结肠癌增殖和EMT中的作用机制，为临床治疗效果的预判与新治疗靶点的寻找提供线索。