Cancer cells are defined by their ability for uncontrolled growth.
For over 80 years, the reigning idea has been that cancer cells fuel their explosive growth by soaking up glucose from the blood, using its energy and atoms to crank out duplicate sets of cellular components. Copious amounts of glucose are taken up to make lipids that are assembled into cell membranes. Cell membranes are the thin veils that separate the contents of a cell from its environment.
Scientists used to work with radioactively tagged glucose to show that practically all the lipids inside tumor cells were made from glucose the cells took up from the extracellular environment. This was a finding that seemingly corroborated the “glucose hypothesis.”
Although this hypothesis makes sense, it could be wrong.
Researchers have since discovered that proliferating fibroblasts make most of their lipids from glucose only if they are grown in standard cell-culture medium, which is nutrient-rich but lipid-poor.
When researchers spiked the culture medium with lipids raising concentrations to those typical of blood, the cells preferred to scavenge lipids from the medium rather than synthesizing them. Under these conditions, rapidly dividing cells took up no more glucose than cells that were dividing.
The effect was discovered in cultures of fibroblasts, which divide until they touch one another and then stop. This gives scientists a chance to compare the metabolism of proliferating and quiescent cells.
Researchers were intrigued by these findings and checked for it in two cancer-cell lines, the famous HeLa cells, and a lung cancer cell line. These cell lines responded less strongly but similarly to lipid concentrations.
These findings call into question aspects of cancer research and treatment founded on the glucose hypothesis.
If the findings suggest that cancer cells might not respond as hoped to drug that block the glucose uptake, it also suggests blocking lipid uptake might be effective.
More research is necessary in order to come to a conclusion.
