Origination of Cancer

Our cells produce energy through aerobic (with oxygen) and anaerobic (without oxygen) metabolism. Both of these metabolic pathways produce ATP which is the main energy source of our bodies. One method for the destruction of the respiration of body cells is through the removal of oxygen. This causes the cell to produce oxygen through fermentation. As the Nobel prize winner, Dr. Warburg describes it, normal cells are developed into cancer cells by an increase in fermentation. The respiration of all cancer cells is damaged resulting in the cells not being able to produce energy using aerobic metabolism. Instead, cancer cells can only produce energy by fermentation which produces lactic acid as a by-product.

The link between hypoxia and the shift from oxidative phosphorylation to glycolysis has been studied thoroughly, but the journal by Dr. Cui shows the direct relationship between hypoxia and accelerated cancer growth. When hypoxia levels increase, oxidative phosphorylation as the producer of ATP decreases while glycolysis increases which accelerates glucose uptake from blood circulation to make up for the energy that is lost. This shift to the oxygen-less metabolism, leads to increased cancer cell numbers, further increasing hypoxia. This leads to a cycle of accelerated cancer cell growth. Dr. Warburg discovered that glycolysis is activated even when oxygen is available in cancer cells. The work by Dr. Cui shows that the reduced efficiency in production energy that can be caused by hypoxia leads to an increased uptake of glucose from the blood needed for glycolysis which furthers the growth of cancer cells.

In summary, the research by Dr. Cui explains that through the growing stages of cancer, there is a growth trend in hypoxia levels, which speeds up the cell division rate. The two factors that contribute to the cancer growth are hypoxia, and miscoupling of increased nutrient requirements caused by the energy inefficiency vs. increased cell division signaling, caused by the build-up of nutrients. Hypoxia could also lead to transition from normal fast-growing cells to cancer cells since hypoxia can activate emergency DNA repair machinery which may cause more DNA mutations. This study provides great insight on how the lack of oxygen has large impacts on cancer cell proliferation.

Available evidence is in favour of the view that cancer is a metabolic disease with impaired energy metabolism. Lack of aerobic glycolysis in dysfunctional mitochondria leaves the cells acurely short of energy. Abundance of oxygen supplied with voluntary respiration may prevent the origination of cancer, athough once originated it may not be reversible with or without it.

Sources:
Cui, J., Mao, X., Olman, V., Hastings, P. J., & Xu, Y. (2012). Hypoxia and miscoupling between reduced energy efficiency and signaling to cell proliferation drive cancer to grow increasingly faster. Journal of Molecular Cell Biology,4(3), 174-176. doi:10.1093/jmcb/mjs017
Warburg, O. (1956). On the Origin of Cancer Cells. Science,123(3191), 309-314. doi:10.1126/science.123.3191.309 Thomas N Seyfried and Laura M Shelton.  Cancer as a metabolic disease. Nutrition & Metabolism 7:7 at http://www.nutritionandmetabolism.com/content/7/1/7. 2010