A new study by scientists at the Massachusetts Institute of Technology (MIT) found that cancer cells use an unusual process of multiplication. The study, which answers a long-standing mystery about the proliferation of unhealthy cells in the human body, will be published in Molecular cell journal.
The study was conducted by MIT biologists Matthew Vander Heiden, lead author of the new study, and lead authors, former MIT graduate and postdoctoral student Alba Luengo (Dr. ’18) and graduate, Zhaoqi Li. Their research has shown that the metabolic procedure, known as fermentation, helps cancer cells regenerate large amounts of molecules called NAD +, which they need to synthesize DNA and other important molecules. Speaking to MIT News, Heiden said that according to their study in certain circumstances, cells must make more electron transfer reactions, which require NAD + to produce molecules such as DNA.
Fermentation is one way in which cells can convert the energy found in sugar into adenosine triphosphate (ATP). ATP is a chemical used by cells to store energy for their needs. People use a process called aerobic respiration in which cells break down sugar to access more ATP. However, cells switch to a less efficient method called fermentation when there is a lack of oxygen in the cells.
German chemist Otto Warburg has discovered that cancer cells usually metabolize sugar through the fermentation process. Scientists have since proposed various theories to justify why cancer cells move to a more lethargic way of breaking down cells, but with little success.
To understand this reason, MIT scientists have hampered the ability of cancer cells to perform the fermentation process. With this, they noticed that the growth of cancer cells was prevented. The researchers then introduced another method of cell growth by stimulating cells to produce NAD +, a molecule that helps cells remove extra electrons that are left out when cells produce molecules such as DNA and proteins.
With this experiment, the researchers found that the cells began to proliferate again, despite their inability to perform fermentation. The results of this study led researchers to conclude that when cells grow rapidly, they need more NAD + than they need ATP. And because in aerobic respiration, cells produce a large amount of ATP and some NAD +, they go on to ferment. Scientists have found that if cells accumulate more ATP than they can consume, their respiration sedates and NAD + production is also reduced.