Figure 1

GSK3β inhibitors induce mitotic exit in the presence of spindle toxins. (A) HeLa cells were exposed to 20 nM epothilone B (EPO) for 24 hours. The GSK3 inhibitor, SB415286 (SB), was then added and the cells imaged 16 hours later. (B–E) Taxol (1 μM) or Nocodazole (3.3 μM) was added to Hela, HT1080, or HCT116 cells for 12–14 hours. GSK3 inhibitors and DMSO or NaCl controls were added for 2.5 hours and then mitotic index determined in a blinded manner using chromosome spreads. GSK3 inhibitors: SB, 25 μM SB415286; RO, 1 μM RO318220; 20 mM LiCl. Bars represent standard deviation. ^*p < 0.05 using a student’s t-test. (F) HeLa M cells were exposed to Taxol(1 μM) for 12–14 hours, followed by 2 hours of MG132 and SB or RO or DMSO control. (G) MEFs from Gsk3β-null embryos or wild-type littermates were exposed to Taxol for 14 hours and mitotic index determined using chromosome spreads. (B–F) Experiments were repeated in triplicate with at least 100 cells measured per repeat. Error bars represent standard deviation. Standard deviation was calculated using triplicates from a single repeat. TTest analysis was performed to confirm if the difference was significant. * indicates p < 0.05.