Cancer metabolism: major remodeling of cellular energy production and metabolic pathways in tumors
Do cancer cells have altered metabolism?
Altered metabolism is one of the hallmarks of cancer cells. The best-known metabolic abnormality in cancer cells is the Warburg effect, which demonstrates an increased glycolysis even in the presence of oxygen.
What causes cancer cells to be immortal?
With each cell division, telomeres shorten until eventually they become too short to protect the chromosomes and the cell dies. Cancers become immortal by reversing the normal telomere shortening process and instead lengthen their telomeres.
How does cancer affect metabolism?
Oncogenes and tumor suppressors regulate metabolism. While mutations in metabolic enzymes hardwire metabolism to tumorigenesis, mutations that activate oncogenes or inactivate tumor suppressors appear to “softwire” cancer genes to metabolism, because metabolic enzymes are directly regulated by these cancer genes.
Do cancer cells produce more co2?
This phenomenon is known as the Warburg Effect, after its discoverer Otto Warburg, and is also known (somewhat confusingly) as aerobic glycolysis. Cancer cells consume more than 20 times as much glucose compared to normal cells, but secrete lactic acid instead of breaking it down completely into carbon dioxide.
How is cancer metabolism different?
Normal cells do not metabolize glucose to lactate when oxygen is available. Only when the oxygen is absent or limiting do normal cells resort to anaerobic glycolysis or metabolism of glucose to lactic acid. In contrast, cancer cells metabolize glucose to lactate even in the presence of oxygen (aerobic glycolysis).
Where does aerobic glycolysis occur?
Glycolysis occurs in the cytoplasm where one 6 carbon molecule of glucose is oxidized to generate two 3 carbon molecules of pyruvate. The fate of pyruvate depends on the presence or absence of mitochondria and oxygen in the cells.
What causes tumorigenesis?
Human tumorigenesis can be considered to be the accumulation of genetic mutations within cells that affect both the tumor suppressor genes as well as the oncogenes.