Yang Chendong, Jiang Lei, Zhang Huafeng, Shimoda Larissa A, DeBerardinis Ralph J, Semenza Gregg L
Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
School of Life Science, University of Science and Technology of China, Hefei, PR China.
Methods Enzymol. 2014;542:425-55. doi: 10.1016/B978-0-12-416618-9.00022-4.
Hypoxia is a common finding in advanced human tumors and is often associated with metastatic dissemination and poor prognosis. Cancer cells adapt to hypoxia by utilizing physiological adaptation pathways that promote a switch from oxidative to glycolytic metabolism. This promotes the conversion of glucose into lactate while limiting its transformation into acetyl coenzyme A (acetyl-CoA). The uptake of glucose and the glycolytic flux are increased under hypoxic conditions, mostly owing to the upregulation of genes encoding glucose transporters and glycolytic enzymes, a process that depends on hypoxia-inducible factor 1 (HIF-1). The reduced delivery of acetyl-CoA to the tricarboxylic acid cycle leads to a switch from glucose to glutamine as the major substrate for fatty acid synthesis in hypoxic cells. In addition, hypoxia induces (1) the HIF-1-dependent expression of BCL2/adenovirus E1B 19-kDa interacting protein 3 (BNIP3) and BNIP3-like (BNIP3L), which trigger mitochondrial autophagy, thereby decreasing the oxidative metabolism of both fatty acids and glucose, and (2) the expression of the sodium-hydrogen exchanger NHE1, which maintains an alkaline intracellular pH. Here, we present a compendium of methods to study hypoxia-induced metabolic alterations.
缺氧是晚期人类肿瘤中的常见现象，常与转移扩散和不良预后相关。癌细胞通过利用促进从氧化代谢向糖酵解代谢转变的生理适应途径来适应缺氧。这促进了葡萄糖向乳酸的转化，同时限制了其向乙酰辅酶A（乙酰-CoA）的转化。在缺氧条件下，葡萄糖摄取和糖酵解通量增加，这主要归因于编码葡萄糖转运蛋白和糖酵解酶的基因上调，这一过程依赖于缺氧诱导因子1（HIF-1）。乙酰-CoA向三羧酸循环的输送减少，导致缺氧细胞中作为脂肪酸合成主要底物的物质从葡萄糖转变为谷氨酰胺。此外，缺氧诱导（1）BCL2/腺病毒E1B 19 kDa相互作用蛋白3（BNIP3）和BNIP3样蛋白（BNIP3L）的HIF-1依赖性表达，它们触发线粒体自噬，从而降低脂肪酸和葡萄糖的氧化代谢，以及（2）钠氢交换体NHE1的表达，其维持细胞内碱性pH值。在此，我们介绍了一系列研究缺氧诱导的代谢改变的方法。
