Question

Bone marrow or cancer cells are constantly dividing, i.e., they are in constant need of fatty acids for synthesizing membranes of the progenitor cells. How do these make sure that: (a) there is sufficient acetyl-CoA in the cytoplasm for fatty acids synthesis, (b) there is sufficient NADPH in the cytoplasm and (c) fatty acids are not degraded via β-oxidation?

Answer 1

Answer: Maintenance of lipid homeostasis is important for the survival of stem cells. Lipids are the building blocks of cell membranes. Cancer cells and stem cells express high levels of fatty acid synthase and produce fatty acids at a high rate. There is an increase in the activity of acetyl-CoA carboxylase. The cell having higher division capabilities alter fatty acid metabolism to meet the needs of rapid cell development. Many of the fatty acid synthesis are overexpressed. Normal cells usually have slow lipid metabolism and instead depends on dietary intake to meet their fatty needs. While normal cells mostly uptake fatty acids as per requirement, cancer cells reactivate de novo fatty acid synthesis. Fatty acid synthase inhibitors are used as anticancer drugs. Rapid dividing cells express high levels of monoacylglycerol lipase enzyme that releases free fatty acids from lipids. There is accumulations of lipid droplets that generates maximum amount of ATP and NADPH.