Cues for cancer stem cells origin

Abstract

Neural stem/progenitor cells (NSPC) can differentiate into neurons and glial cells in the central nervous system. Interestingly, NSPC biology is being applied to the study of human brain tumours, since these cells share some common features with glioma cells. However, it is not known the developmental stage with more similarities to glioma cells, or the most susceptible to malignant transformation. We aimed to identify the stage(s) in the NSPC differentiation process towards astrocytes where cells acquire phenotype characteristics comparable to glioma cells. NSPC that were obtained from E15 mouse brain, were grew as neurospheres (NS) and induced to astroglial differentiation until 7 days in vitro (DIV). After the cellular characterization of NS and differentiating cells, tumour-related factors were evaluated and their behavior compared to the one of GL261 mouse glioma cells. Astroglial differentiation led to a decrease in progenitor cells, as expected. Multidrug resistance-associated protein 1 expression decreased and autophagy marker increased with differentiation. The vascular endothelial growth factor (VEGF), matrix metalloproteinases and S100B protein increased until 2/3 DIV, while the 1 DIV cells showed the highest migratory potential towards the chemotactic VEGF or GL261-conditioned media. Comparison of data with glioma cells characteristics point to the first and second days of NSPC differentiation to astrocytes as the stages closing matching GL261 cells, and likely the most vulnerable to malignancy transformation.