Apcin is an inhibitor of the E3 ligase activity of the mitotic anaphase-promoting complex/cyclosome (APC/C). Apcin competitively binds to Cdc20 and prevents substrate interaction and ubiquitylation required for continuation of mitosis. Apcin enhances the effect of the APC/C inhibitor N-4-tosyl-L-arginine methyl ester and its prodrug, proTAME, leading to an increase in the number of cells in mitosis, a longer mitotic duration, and greater stabilization of cyclin B1, cycB1-NT, securin, and cyclin A2. Apcin, in combination with proTAME, synergistically increases apoptosis in multiple myeloma cells.

References:
[1]. Sackton, K.L., Dimova, N., Zeng, X., et al. Synergistic blockade of mitotic exit by two chemical inhibitors of the APC/C Nature 514(7524), 646-649 (2014).
[2]. Lub, S., Maes, A., De Veirman, K., et al. Inhibiting the anaphase promoting complex/cyclosome induces a metaphase arrest and cell death in multiple myeloma cells Oncotarget 7(4), 4062-4076 (2016).