Fig. 5: CPZ produces a decrease in nuclear PKM2 concentration in GBM cells.

A Representative confocal microscopy images of U-87 MG, U-251 MG, TS#1, and TS#163 GBM cell lines and RPE-1 non-cancer cells untreated, CPZ-treated or DASA-58-treated. Green fluorescence shows PKM2, while merging with DAPI (blue) highlights the nuclear structures. The smaller pictures at the right of each image (zoom) reproduce at higher magnification the contents of the red square in each bigger microphotography. Histograms on the right quantify the reduction in nuclear PKM2 mean intensity in CPZ-treated cells (red) or in DASA-58-treated cells (light blue) when compared with controls (black), as evaluated via the microscope software. N ≥ 150 nuclei for CTL and CPZ and ≥80 for DASA-58-treated cells. Scale bars are shown in each microphotography. Asterisks denote statistical significance (*p < 0.05; **p < 0.01; ***p < 0.001). B The protein levels of PKM2 were assessed using western blotting after subcellular fractionation in all of the cell lines mentioned above. To normalize the results, GAPDH and H3-Histone were used for enriched cytoplasmic and nuclear protein lysates, respectively. Representative western blots on the left show a significant decrease in nuclear PKM2 levels after exposure to CPZ for GBM cells and neurospheres. Histograms on the right quantify the expression levels of PKM2 protein, determined by western blotting, in CPZ-treated GBM cells and in the non-cancer RPE-1 cell line compared to their untreated counterparts (*p < 0.05; **p < 0.01;***p < 0.001). N=3.