NPM1 and glioma: Less is however known about the dynamics of NPM1 in glioma cells and neural stem cells when they are exposed to a low concentration of Act D. To investigate the effects of RNA pol I inhibition on NPM1 localization, we treated differentiated mouse NSCs and a human glioma cell line U1242MG with Act D. To obtain comparable results, since U1242MG harbors mutant p53 we used Trp53−/− NSCs in these experiments.