Figure 2.

The regulation of glucose metabolism in cancer cells. When glucose enters the cell through a glucose transporter, it is phosphorylated by HK to glucose-6-phosphate, which is further metabolized by glycolysis to pyruvate in the cytosol. Under aerobic conditions, normal cells use pyruvate dehydrogenase (PDH) to convert most pyruvate to acetyl-CoA. The acetyl-CoA is then oxidized via the TCA cycle, providing sources of ATP synthesis. In contrast, the metabolic pathways of glucose utilization in cancer are changed from ATP generation by oxidative phosphorylation to ATP generation through glycolysis. Also, for cell proliferation to occur, cancer cells require the synthesis of new macromolecules (for example, nucleic acids, lipids, proteins). Key enzymes that may be promising targets for cancer therapy are highlighted in red. TCA enzymes that are known to be mutated in cancer are shown in purple: IDH2, SDH, and FH.