APC/C dysfunction results in CIN buffering and adaptation to extreme CIN. A and B, RPE1/H2B-mCherry cells were arrested in mitosis using 40 nmol/L STLC, collected by shake-off, and released into media containing 3 μmol/L proTAME or DMSO (t = 0h). APC/C dysfunction results in CIN buffering and adaptation to extreme CIN. A and B, RPE1/H2B-mCherry cells were arrested in mitosis using 40 nmol/L STLC, collected by shake-off, and released into media containing 3 μmol/L proTAME or DMSO (t = 0h). Stacks were acquired every 3 minutes to determine anaphase onset (A) and the presence of lagging chromosomes (B; error bars, mean ± 95% CI). Sample images from movies are shown, and the arrow indicates a lagging chromosome in a cell without proTAME. Representative images are shown (scale bar, 10 μm). C, Degradation kinetics of cyclin A2-Venus fluorescence quantified from unsynchronized single cells as they progress through mitosis. 1.5 μmol/L proTAME or DMSO was added 2 hours before imaging. Total cell fluorescence was quantified and normalized to the level at NEBD. Curves end at anaphase onset (n = 24 cells per condition; error bars indicate SD; ***, P < 0.0001 Student t test). Time to reach 50% maximum intensity was used for statistical analysis. Laurent Sansregret et al. Cancer Discov 2017;7:218-233 ©2017 by American Association for Cancer Research