基于Wnt/β-catenin通路探讨Caudatin调控内质网应激介导的肝细胞“炎-癌”转化作用机制

Caudatin is an active compound selected from Polygonum multiflorum. Previous studies showed a regulation of Caudatin on endoplasmic reticulum stress (ERs) of hepatocyte and inhibition on the proliferation of hepatoma cells by Wnt1 /β-catenin pathway. We speculated that: " Effect of Caudatin on ERs-mediated  “inflammation--carcinogenesis” transformation of hepatocyte might be associated with its regulation on Wnt1/β-catenin signaling pathway". Based on Wnt1 / β-catenin pathway, we used chemical agent to induce hepatic carcinoma animal model and normal liver cell HL-7702 damage model, and then apply molecular biology, gene chips, chemoprevention, knockout, siRNA interference and other methods, to explore the intervention of Caudatin on pathological inflammatory   microenvironment and ERs feature change of liver cancer. The association of "Wnt1/β-catenin-ERs- ‘inflammation - carcinogenesis transformation’" was displayed. The differentially expressed key target was screened by differential gene chip and suspension microarray technology. The regulatory of Caudatin on Wnt1/ β-catenin pathway was further explored to clarify the underlying mechanism of Caudatin on “inflammation--carcinogenesis” transformation of hepatocyte. This research project provides the foundation for the development of new drugs for liver cancer chemoprevention.

Caudatin为从中药白首乌中筛选出来的活性化合物。前期研究表明Caudatin调节肝细胞ERs并通过Wnt1/β-catenin抑制肝癌细胞增殖。我们推测：caudatin可能通过调控Wnt1/β-catenin信号通路降低ERs介导的肝细胞的‘炎-癌’转化。本研究基于Wnt1/β-catenin通路，拟采用化学诱导肝癌动物模型及正常肝细胞HL-7702损伤模型，结合分子生物学、基因芯片、基因敲除、siRNA干扰等方法，探索Caudatin干预肝癌病理进程炎症环境、ERs特征改变，挖掘“Wnt1/β-catenin-ERs-炎癌转化”的关联性；采用差异蛋白基因芯片和悬浮芯片技术，筛选差异表达的关键靶标；深入探索Caudatin对Wnt1/β-catenin的调控作用，阐明Caudatin防治肝癌“炎-癌”转化的作用，为开发肝癌化学预防新药奠定基础。

干预“炎-癌”转化成为肝癌防治的重要环节，而肝癌的“炎-癌”转化与ERs应激和病理信号相关。Caudatin为从中药白首乌中筛选出来的活性化合物，本项目采用DEN化学诱导肝癌动物模型及内质网应激激活剂诱导肝细胞LO2损伤模型，明确 Caudatin 对肝癌炎癌转化的干预作用；确证该干预过程中对内质网应激的调控作用；揭示 Caudatin 通过调控Wnt1/β-catenin干预肝癌炎症机制；探究Wnt1/β-catenin、ERs、“炎-癌”转化三者关联性。研究发现：Caudatin改善DEN所致肝癌模型大鼠肝脏的病理学改变、肝功能受损、抑制炎症细胞浸润和炎症因子表达，降低了DEN肝癌模型大鼠肝癌发病率、结节和肝癌前病变；DEN显著激活PERK-eIF2α-ATF4通路和ATF6通路，表现为显著增强p-PERK p-eIF2α和下游信号分子(ATF4和GADD34)的表达，在Caudatin作用后，PERK和eIF2α的磷酸化被抑制，ATF6 被抑制，而对IRE1信号通路的影响较小；DEN处理后下调Wnt1表达以及β-catenin磷酸化，而Caudatin可以改善DEN所致的Wnt/β-catenin 通路抑制，从而抑制肝细胞 的“炎-癌”转化。DEN组大鼠肝脏中p-p65的表达增高，而Caudatin可以显著下调p-p65，结合前期DEN大鼠模型的炎症因子和抑制肿瘤的结果，提示Caudatin能抑制DEN诱导的大鼠肝脏的炎癌转化。本项目深入揭示Caudatin 防治肝癌“炎-癌”转化的作用机制，为中药防治肝癌提供新的策略和靶点。