生物节律分子NPAS2促进肝癌细胞糖代谢重编程的作用机制研究

In tumor development and progression, tumor cells finally form rapidly growth, division and other characteristics by regulating glucose metabolism process (glucose metabolism reprogramming). Numerous studies and our recently published literature all provened circadian genes have important effect on many aspects of tumor celles, especially in the metabolism (including glycometabolism), but the specific regulatory mechanism is not fully understood. We recently discovered that molecules of circadian gene NPAS2 overexpressed in hepatocellular carcinoma(HCC)， and in hepatoma cells NPAS2 can significantly promoted glycolysis, inhibition of mitochondrial oxidative phosphorylation, suggesting that NPAS2 may be the key molecules involved in glucose metabolism reprogramming. The project intends to study the current international hot area - biorhythm regulation perspective. With the basis of previous work about NPAS2 and HCC study. Using established stable low and high expression NPAS2 hepatoma cell model system analysis of the molecule to promote liver cell glycolysis, oxidative phosphorylation inhibit biological effects, discuss the role of molecular signaling pathways, thereby elucidate the molecular mechanisms of NPAS2 promote hepatoma cell glycolysis and inhibit oxidative phosphorylation. These studies have not only discovered a new mechanism for the regulation of glucose metabolism in hepatoma cell, but also can provide a new potential target for the treatment of HCC.

在肿瘤的发生和进展中，肿瘤细胞通过调控糖代谢进程(即糖代谢重编程)，最终使肿瘤细胞具有快速生长、分裂的特性。大量文献和我们最近发表的研究证明，生物节律基因对肿瘤的许多表型都发挥着重要调控作用，尤其在代谢方面(包括糖代谢)，但具体调控机制尚不完全清楚。我们最近在肝癌组织中发现生物节律分子NPAS2异常高表达，同时在肝癌细胞中发现NPAS2显著促进糖酵解，抑制线粒体氧化磷酸化，提示该分子可能是一个参与糖代谢重编程调控的关键分子。本项目拟借助前期有关NPAS2和肝癌研究的工作基础，利用已建立的稳定低表达和高表达NPAS2的肝癌细胞模型，深入分析该分子促进肝癌细胞糖酵解、抑制线粒体氧化磷酸化的生物学作用，探讨分子信号作用通路，最终阐明NPAS2分子促进肝癌细胞糖代谢的分子网络调控机制。本项目将为肝癌细胞糖代谢调控的机制提供新的视角，同时也为肝癌的靶向治疗提供新靶点。

昼夜节律基因的失调与肿瘤的发生密切相关。然而，昼夜节律基因是否调节肿瘤细胞新陈代谢的重编程，目前尚不清楚。在此，我们发现NPAS2作为一个核心的昼夜节律分子，主要通过两种机制对肝癌细胞葡萄糖代谢的重编程起重要作用。一方面，NPAS2上调糖酵解基因GLUT1、HK2、GPI、ALDOA、ENO2、PKM2和MCT4的表达。另一方面，NPAS2下调过氧化物酶体增殖物激活受体γ共激活因子1α（PGC-1α）的表达。从机制上讲，HIF-1α是NPAS2的直接转录靶点，它介导HCC细胞糖酵解基因的上调和线粒体生物合成的下调。此外，我们发现NPAS2的表达上调主要是由于miR-199b-5p的下调所引起的。另外体外和体内实验进一步表明HIF-1α介导的糖代谢重编程在NPAS2调控的肝癌细胞生长和转移中起着关键作用。我们的发现表明NPAS2在糖代谢重编程中起着重要作用，提示NPAS2可能是肝癌潜在的治疗靶点。