Figure 6

The phenanthridine PJ-34 prevented bi-polar clustering of extra-centrosomes in the tested human cancer cells. Top: PJ-34 interfered with the bifocal clustering of centrosomes in the indicated human cancer cells (DLD1, grey line, solid grey dots; H1299, grey line, empty diamonds; HeyA8, grey line, solid black squares; PANC1, black line, empty triangles) fixed 72 hours after application of PJ-34 at the indicated concentrations. Control and treated cells were permeabilized and immunolabeled for α- and γ-tubulin, for the detection of spindles (green) and centrosomes (red), respectively, as described below. The percentage of multi-focal spindles was calculated out of 20 spindles detected in randomly selected fixed cells by confocal microscopy in 3 different experiments. Bottom: Confocal images indicate scattered centrosomes and multi-focal spindles in randomly selected fixed cells in mitosis of the indicated cell-lines, 48 hours after application of PJ-34 at the indicated concentrations. Control (untreated) and treated cells were permeabilized and immunolabeled for α- and γ-tubulin (green and red, respectively). Chromosomes were labeled with DAPI reagent (blue).