TGM2在活化肝星状细胞诱导肝癌细胞糖代谢重构中的作用及机制研究

Inflammation and metabolism are critical factors contributing to the protumorigenic properties of the tumor microenvironment. Hepatic stellate cells (HSC), as the important stroma cells in liver cancer microenvironment, play a key role in inflammation. Our previous study found the metabolic state of hepatocellular carcinoma (HCC) cells altered after co-culturing with activated HSC, with higher glucose and glutamine consumption and lactate secretion, meanwhile, transglutaminase2 (TGM2) expression was up-regulated, making cells in pseudo hypoxia state and promoting tumor cells proliferation. It is indicated that activated hepatic stellate cells promoted tumor glucose metabolic reprogramming, such as aerobic glycolysis, via up-regulation of TGM2 expression in hepatocellular carcinoma cells. We will study the effect of activated HSC on tumor glucose metabolic reprogramming using cells co-culture model, nude-mice subcutaneous tumor model and orthotopic transplantation tumor model with real-time RCR, western blot, RNA interfering technology and proteomic technology and so on. This study will found the new mechanism of the occurrence and development of HCC, based on the effect of activated HSC on tumor glucose metabolic reprogramming, to provide new ideas for the prevention and treatment of HCC.

肿瘤微环境中的炎症和代谢异常是促进肿瘤发生发展的重要因素，肝星状细胞（HSC）是肝癌微环境中的重要间质细胞，在炎症调控中发挥关键作用。前期研究发现，与活化HSC共培养后的肝癌细胞代谢状态改变，表现为葡萄糖和谷氨酰胺摄取率提高，乳酸生成增加；同时发现肝癌细胞中TGM2分子表达显著上调，TGM2过表达可使肝癌细胞处于“假性”缺氧状态，具有促进肿瘤细胞增殖的作用；提示活化HSC通过诱导肝癌细胞表达TGM2进而促进有氧糖酵解等途径重构能量代谢。本课题将通过人肝癌细胞与活化HSC体外共培养模型、裸鼠皮下成瘤和裸鼠原位肝癌移植模型，采用real-time PCR、Western blot、RNA干扰技术、差异蛋白组学和生物信息学等手段，研究活化的HSC对肝癌细胞糖代谢重构的影响以及TGM2分子在其中的作用机制；从活化HSC调节肿瘤糖代谢重构角度，发现肝癌发生发展的新机制，为肝癌的防治提供新的思路。

肿瘤微环境中的炎症和代谢异常是促进肿瘤发生发展的重要因素，肝星状细胞是肝癌微环境中的重要间质细胞，在炎症调控中发挥关键作用。本研究发现，与活化肝星状细胞共培养后肝癌细胞出现糖代谢重构、上皮间质转化及化疗耐药现象，采用差异蛋白组学及信号通路分析证实在这个过程中，组织型转谷氨酰胺酶2（TGM2）分子和一些在糖酵解途径中发挥重要作用的分子（PGK1, LDHA 和ENOG）在肝癌细胞中存在上调现象。本研究通过体内外实验进一步探索其中机制发现，活化肝星状细胞通过炎症信号，促进肝癌细胞中TGM2分子上调；肝癌细胞中TGM2分子可与VHL蛋白结合，而VHL蛋白是常氧状态下HIF-1a降解通路中的关键分子，因此TGM2分子的上调造成了VHL蛋白的耗竭，造成了肝癌细胞中HIF-1a分子在常氧状态下聚集，即假性缺氧状态，进而造成了肝癌细胞出现糖代谢重构、上皮间质转化及化疗耐药现象。本研究从活化肝星状细胞通过TGM2/VHL/HIF-1a通路造成肝肿瘤假性缺氧，调节肝肿瘤糖代谢重构、上皮间质转化、化疗耐药的角度，发现肝癌发生发展的新机制，为肝癌的防治提供新思路。