Figure 1. Mitochondrial accumulation in the perinuclear area in U87^RETO glioblastoma cells upon stress with etoposide.

Panel A1-10 days: MTT staining, untreated control of U87^WT glioblastoma cells. After 10 days, cells were incubated with 1mg/ml MTT for two hours for mitochondrial visualizing (blue). Panel B1-10 days: visualization of mitochondrial accumulation upon etoposide incubation at 5 μg/ml final concentration for a total of 10 days in U87^RETO glioblastoma cells. Perinuclear rearrangement of mitochondria was already seen after 2 days of drug incubation (i.e. day 2 of panel B) and increased during time exposure. Cells depict hypertrophic bodies in response to etoposide stress. Panel C: semi-quantification of mitochondrial fission upon stress with etoposide. Panel C1 (untreated) depicts the mitochondrial distribution by visualizing the expression of Cox IV in U87^WT cells. Panel C2 (etoposide treated) represents the distribution of mitochondria in U87^RETO cells after 10 days of drug exposure as visualized by Cox IV fluorescent detection. Treated cells show hypertrophy and massive perinuclear rearrangement of mitochondria, compared to untreated cells. Panel C3 presents flow cytometric analysis of both U87^WT and U87^RETO cells labeled with red MitoTracker^®. Control: Untreated cells. U87^WT and U87^RETO cells treated with etoposide as described above. Enhanced mitochondrial accumulation could be confirmed. Magnification 40x. The figure is representative of at least n = 3 independent experiments.