Cells need energy to carry out their own processes of growth, division and survival. This need is met by the metabolic pathway of glycolysis, which converts glucose to pyruvate, two energy molecules of ATP and one of NADH (nicotinamide adenine dinucleotide hydrogen).
Pyruvate is then transported into the mitochondria where it is converted to acetyl-CoA. The coenzyme produces the energy molecules NADH and FADH2 (flavin adenine dinucleotide hydrogen 2) through the Krebs cycle, also called the tricarboxylic acid cycle. Hydrogen ions used in the electron transport chain via oxidative phosphorylation (OXPHOS) generate 36 molecules of ATPs.
Cancerous stem cells have been shown to have a higher glycolytic metabolism compared to normal and cancer cells.
This difference could be due to the high expression of glycolytic enzymes such as GLUT1 (glucose transporter 1), HK-1 (hexokinase-1) and PDK-1 (pyruvate dehydrogenase kinase 1), and the high consumption of glucose.
However, several studies have challenged the notion of a preferential reliance of cancer stem cells on the glycolytic metabolic pathway for energy production. These studies suggest that OXPHOS is likely to be the major source of ATP due to increased mitochondrial ROS (reactive oxygen species), higher rates of oxygen consumption, and overall increased mitochondrial function.
Therefore, until there is a better understanding of cancer stem cell metabolism, the development of targeted therapies remains a future therapeutic possibility.
