Brain cancer stem cells improve their ability to compete for limited nutrients in the brain by increasing the expression of the protein that imports glucose into cells. The study, published this week in Nature Neuroscience, provides insight into how these stem cells are able to survive and proliferate in the relatively nutrient-sparse brain and may inform future efforts to develop therapeutics for this type of cancer.
Glioblastoma multiforme (GBM) is the most common and lethal form of brain tumor in adults. As with many cancers, GBM tumor cells have very high energy requirements. However, the cells compete for the very limited amounts of energy, in the form of glucose, available in the brain.
Jeremy Rich and colleagues report that nutrient restriction results in an increase in the survival of tumor-forming cancer stem cells called brain tumor initiating cells (or BITCs). In addition, they find that BITCs increase the expression of glucose transporter isoform, type 3 (or Glut3), a protein which allows the cells to take up glucose more efficiently. However, the authors found that in mice, if the expression of the GLUT3 gene is blocked in these cells, BITC growth and tumor propagation was reduced. Furthermore, they found that GLUT3 expression levels are correlated with GBM severity and prognosis in patients.