促癌因子BTF3转录上调Snail和β-catenin促进直肠癌转移的功能和分子机制研究

Colorectal cancer malignance differentiation and metastasis is the one of the trickiest problem and illustrating how transcription factors play the role in the process is of great significance. In our previous research, the expression level of a novel transcription factor BTF3 ascends with the metastasis of colorectal cancer. In vitro silencing the expression of BTF3 attenuates the migration and reverses Epithelial-Mesenchymal Transition. Subsequent Experiment demonstrated that BTF3 would activate Wnt signaling pathway by up regulating the expression ofβ-catenin. Furthermore the expression of Snail in the EMT process ascends with the expression of BTF3. At last, bioinformatics prediction shows that BTF3 has the binding site of Snail andβ-catenin promoter sequence. Based on this, we provide the hypothesis that BTF3 play the oncogenic role of promoting CRC cells migration and EMT via direct binding to conserved sequencing in the Snail andβ-catenin promoter and activating Wnt signaling pathway. In the subsequent research, we would focus on the elucidation of how BTF3 exert its function with nude mice transplantation tumor experiment. Another key point would be demonstrated how BTF3 transcriptionally activate Snail andβ-catenin expression and Wnt signaling pathway with through EMSA, CHIP and so on. Last but not least, we would evaluate the how the expression of BTF performs as the diagnostic and prognostic biomarker. The research would provide further basis for the understanding of the process of colorectal cancer metastasis and lay foundation for the precision intervention of metastatic CRC.

结直肠癌恶性分化和转移是临床棘手问题，阐明新型促癌转录因子如何参与该过程具有重要意义。我们前期发现BTF3表达丰度随肠癌恶性程度升高而增加，促进肠癌细胞侵袭和上皮间质转化，而进一步研究发现Snail和β-catenin随BTF3表达上调而上升，生物信息学预测显示Snail和β-catenin启动子含BTF3保守结合位点。据此我们认为：BTF3分别通过转录激活Snail和β-catenin促进细胞发生上皮间质转化和激活Wnt信号通路，促进肠癌细胞侵袭和EMT。项目将首先评估BTF3表达作为肠癌诊断和预后标志物的效果；然后分别从细胞和动物水平验证BTF3在肠癌转移过程中的作用，最后通过挽救实验、CHIP、EMSA等方法探讨BTF3对Snail和β-catenin的转录激活作用以及Wnt信号通路的分子机制。本项目将为以BTF3为靶点的肠癌转移的精准治疗提供新思路。

结直肠癌恶性分化和转移是临床棘手问题，阐明新型促癌转录因子如何参与该过程具有重要意义。我们前期发现BTF3表达丰度随肠癌恶性程度升高而增加，促进肠癌细胞侵袭和上皮间质转化，据此我们认为：BTF3促进肠癌细胞侵袭和EMT。项目将首先评估BTF3表达作为肠癌诊断和预后标志物的效果；然后分别从细胞和动物水平验证BTF3在肠癌转移过程中的功能，并利用RNA-seq、ChIP-Seq技术、公共数据库数据挖掘及生物信息学分析等方法研究BTF3上游、下游调控机制，明确BTF3在结肠癌细胞中的作用。体外实验结果显示BTF3敲低能够抑制结肠癌细胞的增殖和迁移，并且导致结直肠癌细胞的早期凋亡，使细胞在细胞周期G0-G1期停滞，这表明BTF3可能促进结肠癌的发生。 因此，BTF3可用作诊断结肠癌的生物标志物，并为肿瘤基因治疗提供分子靶标。体内动物实验验证了这一结论。通过RNA-Seq、ChIP-Seq、公共数据库数据挖掘和生物信息学分析手段我们得知BTF3作为结直肠癌中的癌基因有两种不同的基因功能机制。 作为转录因子，BTF3促进CHD1L的转录和表达，另一方面，BTF3也可能抑制E3泛素连接酶HERC2介导的p53降解。并且 miR-497-5p表达降低导致转录后BTF3含量更高。以上成果将有利于揭示新型转录因子BTF3 在肠癌转移和恶性分化过程中角色，增强我们对结直肠癌转移的理解，并以BTF3 为关键为探索肠癌转移精准干预提供新的靶点和治疗思路。