缺氧应激对肝癌细胞代谢信号通路的调节作用

通过实验阐明在缺氧条件下糖酵解相关基因表达的变化规律及对肿瘤细胞和正常细胞增殖的影响,并探索活性氧(ROS)介导肝癌细胞代谢途径及对相关基因表达和酶活性的调节作用.以SMMC-7721人肝癌细胞和L02正常肝细胞作为研究对象,分别在单纯缺氧及加葡萄糖缺氧条件下,观察细胞生长,并检测糖代谢关键酶:丙酮酸激酶(pyruvate-kinase,PK)、己糖激酶(hexokinase,HK)、琥珀酸脱氢酶(succinic dehydrogenase,SDH)、异柠檬酸脱氢酶(isocitric dehydrogenase,IDH)mRNA表达水平和乳酸脱氢酶(lactate dehydrogenase,LDH)活性.还检测了pkb基因及缺氧诱导因子hif-1的表达.实验结果说明:a.肿瘤细胞较正常细胞具有更强的缺氧耐受性;b.缺氧条件下,糖酵解途径的增强是保证肿瘤细胞能快速增殖的机制之一;c.ROS通过HIF-1介导了糖代谢通路相关酶的基因表达,参与肝癌细胞缺氧信号通路调节,用抗氧化剂干预可以降低肿瘤细胞的缺氧耐受能力.

Regulation of Metabolism Signaling in Heptoma Cells by Hypoxic Stress

In order to investigate the expression of the glycolysis-associated genes and different proliferation between normal cells and tumor cells in response to hypoxia, and to explore the role of reactive oxygen species (ROS) in mediating metabolism of hepatoma cells and in regulating expression of glycolysis-associated genes and enzyme activity, SMMC-7721 hepatoma cell line and the normal liver cell line LO2 were taken as the investigation objects. The cell suppression ratio and surviving ratio were detected respectively under conditions of simple hypoxia, or 5 mmol/L glucose complicated with hypoxia. The mRNA levels of key enzymes that are involved in regulating glyco-metabolism were detected, including the mRNA levels of pyruvate-kinase, hexokinase, succinic dehydrogenase and isocitric dehydrogenase, and the activity of lactate dehydrognase. The proliferation gene pkb and hypoxia-inducible factor-1 (HIF-1) were detected as well. The results suggest that 1. tumor cell can endure severe hypoxia condition than normal cell, 2. under conditions of hypoxia, the strengthening of the glycolytic pathway is one of the important mechanisms to ensure the rapid proliferation of tumor cells, 3. ROS through HIF-1 mediates the changes of the gene expression of the enzyme of the glycometabolism pathway, and takes part in the regulation of the hypoxia-induced signal transduction. And the use of antioxidant will decrease the ability of tumor cell to endure hypoxia.