Figure 6
P-gp inhibitors increase the accumulation and penetration of calcein-AM in MDR prostate cancer spheroids. Panel A: Calcein accumulation in 3D-spheroids. Upper panel – After 100 minutes of incubation with 2.5 µM of the P-gp substrate calcein-AM, fluorescence images of the spheroids were recorded. DMSO, 0.5% final volume; compounds 29, 34 or 45 at 15 µM. Scale bar indicates 1000 µm. Lower panel – 3D surface plots representing the pixel intensities of the corresponding images from the experiments above. Panel B: Time course of calcein accumulation. Fluorescence images of the spheroids treated with vehicle only or P-gp inhibitor 29 were obtained over 20 minute intervals using a GFP filter as described in panel A. Increases in calcein accumulation in the presence of compound 34 or 45 were observed to be similar to those shown with compound 29 (data not shown).
