代谢酶PGK1在肝癌细胞增殖中的功能与调控机制研究

Aerobic glycolysis is an unique metabolic pathway specific to tumor cell, and it has become a hot spot in the cancer research field because of its obvious potential to be used as therapeutic target for cancer treatment. Phosphoglycerate kinase 1 (PGK1), is a crucial enzyme in the aerobic glycolysis pathway, catalyzing the conversion of 1,3-diphosphoglycerate to 3-phosphoglycerate and producing a ATP. The roles of PGK1 in the proliferation of tumor cells remain unclear, although it has been observed over-expressed in multiple cancer types.We have observed high expression of PGK1 in hepatocellular carcinoma (HCC) tissue,compared to adjacent normal tissue. The primary goal of this proposal is to characterize the regulatory function of PGK1 in the proliferation control of hepatocellular carcinoma cells. By combining cell biology and biochemical methods including cell growth curve, soft agar colony formation assay, and xenograft nude mice model, the value of PGK1 as a potential anti-HCC therapeutic target will be examined. As another major focus of this proposal, we will also investigate the molecular mechanisms by which PGK1 functions are regulated by ubiquitin-dependent degradation and Tyrosine/Serine phosphorylation events as well as to identify novel PGK1 interacting proteins in hepatocellular carcinoma cells. This work possibly will provide alternative means for PGK1 inhibition, given that PGK1 specific inhibitor is currently unavailable.

有氧糖酵解是肿瘤细胞特异的代谢形式，对有氧糖酵解通路的研究正成为癌症研究的一个热点领域。磷酸甘油激酶（phosphoglycerate kinase 1, PGK1）是糖酵解通路中的重要催化酶，具体功能是催化1，3-二磷酸甘油转换为3-单磷酸甘油并生成ATP的化学反应。我们的前期数据表明，PGK1在肝细胞癌组织中呈现高表达，但其在肿瘤细胞生长增殖过程中的功能及调控机制并不清楚。本项目的设计立足于肝癌细胞研究体系，利用一系列分子生物学与细胞生物学手段，结合动物实验，将全面研究PGK1对肝癌细胞生长增殖、体外克隆形成、及裸鼠成瘤等肿瘤细胞特征的调控功能，以评估PGK1作为抑制肝癌的分子靶标的潜在价值。本项目的另一部分工作将集中于深入研究肝癌细胞中PGK1在翻译后修饰水平上，被TRIM21介导的泛素化降解通路、及酪氨酸-丝氨酸激酶通路等信号转导网络所调控的分子机理，探索间接调控PGK1的新策略。

有氧糖酵解是肿瘤细胞特异的代谢形式，对有氧糖酵解通路的研究正成为癌症研究的一个热点领域。磷酸甘油激酶（phosphoglycerate kinase 1, PGK1）是糖酵解通路中的重要催化酶，具体功能是催化1，3-二磷酸甘油转换为3-单磷酸甘油并生成ATP的化学反应。有证据表明，PGK1在某些肿瘤类型中呈现高表达，但其在肿瘤细胞生长增殖过程中的功能及调控机制并不清楚。我们首先发现PGK1在肝癌病例的组织中高表达，并与患者术后的肿瘤复发、转移等预后密切相关。通过RNA干扰等手段干预PGK1的表达，能够显著抑制肝癌细胞株的糖代谢效率、并减缓细胞增殖和裸鼠成瘤，提示PGK1的高表达可能是肝癌发展过程中的一个重要促进因子。后续的机制研究证实，PGK1在多个位点存在乙酰化修饰，并且鉴定了一个对PGK1的功能起到正调作用的K323乙酰化位点，进而鉴定了乙酰化该位点的乙酰转移酶PCAF，及负调控该位点的去乙酰化酶SIRT7。这些工作有助于进一步研究癌症进展过程细胞代谢重编程的机制，并提供了研究肝癌的一个新角度与分子靶标。