PFKFB3和Wnt/β-catenin互作调控细胞自噬促进结肠癌的作用及机制

Colon cancer bears multidrug resistance and is prone to metastasis and recurrence, yet the mechanism is not fully understood. As two targets of cancer therapy, PFKFB3 and Wnt/β-catenin signaling pathways are tightly related with pro-proliferation Akt signaling, however, the crosstalk between them has not been reported until our former results showed that PFKFB3 and β-catenin regulate/interact with each other. In addition, it is contradictory to understand the role of autophagy on cell viability and cell death in colon cancer, and the relevance between autophagy with tumorigenesis and development of colon cancer is largely unknown. Utilizing colon cancer cell lines, xenograft nude mice and tissue microarray of colon cancer (with complete clinicopathological information) as the research models, we will determine: 1) the relevance of PFKFB3/autophagy levels with colon carcinogenesis and progression; 2) the crosstalk between PFKFB3 and Wnt/β-catenin signaling pathway; 3) PFKFB3/Wnt signaling in regulating autophagy and proliferation/invasion; 4) the effect of autophagy on chemotherapeutic agents with the inhibition of PFKFB3 and Wnt signaling. This project is expected to reveal the crosstalk between PFKFB3 and Wnt/β-catenin signaling pathway, and the relevance between PFKFB3/autophagy with tumorigenesis, development and chemotherapy efficacy of colon cancer. Meanwhile, we expect to uncover the tumorigenesis mechanism, and explore potential therapeutic strategy for colon cancer.

结肠癌常见多药耐药性，易复发转移，但机制尚不完全清楚。作为肿瘤治疗的靶点，糖酵解调节蛋白PFKFB3与经典Wnt信号通路均与促增殖的Akt信号通路关联紧密，但两者之间的互作还未见报道，我们前期发现PFKFB3与β-catenin存在蛋白相互作用。细胞自噬对结肠癌细胞活性及死亡的调控存在争议，且其与结肠癌发生发展的相关性尚未见报道。本研究将以结肠癌细胞系、裸鼠移植瘤及结肠癌的组织芯片为对象，探究1）PFKFB3及细胞自噬与结肠癌发生发展的相关性；2）PFKFB3与经典Wnt信号通路的内在关联；3）PFKFB3与经典Wnt的互作对结肠癌自噬的调控及增殖/迁移的影响；4）联合抑制上述两条通路，评价细胞自噬对化疗疗效的影响。研究结果将揭示PFKFB3及Wnt信号通路的内在关联，阐明细胞自噬在结肠癌发生发展及化疗中的作用，探索结肠癌发生的新机制及潜在的治疗靶点，为结肠癌的靶向治疗提供理论依据。

作为糖酵解过程中的关键调节蛋白，许多研究已经表明PFKFB3参与多种生理及病理过程，如参与调节代谢、血管生成及细胞自噬等。PFKFB3的活性受到多种因子的调控，如缺氧、AMPK及AKT信号通路；然而，也有研究表明PFKFB3可以作为AMPK及AKT的上游发挥作用。此外，PFKFB3在多种肿瘤细胞中高表达，是潜在的肿瘤治疗靶点。在本研究中，我们发现PFKFB3与β-catenin能够互相调控并且存在相互作用。.在结直肠癌临床样本中，两者均高表达。利用结直肠癌组织芯片及TCGA数据库，我们发现PFKFB3与β-catenin与结直肠癌的进展相关，高表达时生存期相对较短，并且在表达上存在相关性。PFKFB3影响化疗药物的敏感性。奥沙利铂（Oxa）促进细胞自噬的同时诱导PFKFB3的表达，而抑制PFKFB3阻断细胞自噬的同时增强了Oxa的细胞毒性。除了参与调节细胞自噬和细胞凋亡， PFKFB3小分子抑制剂PFK-15诱导了坏死性凋亡的发生。值得注意的是，阻断坏死性凋亡过程降低了PFK-15诱导的细胞核损伤，这一发现将糖酵解、细胞死亡及细胞核稳定联系在一起。最后，我们还探究了PFKFB3对AMPK及AKT信号通路的调节，证明了AMPK的激动剂AICAR通过抑制AKT信号增强PFK-15的细胞毒性。本项目深入探讨了PFKFB3在结直肠癌增殖、迁移及治疗中的作用，为在结直肠癌中以PFKFB3和β-catenin为靶点探索新的治疗策略提供了理论基础。