Figure 7. Degradation of PML/RARA hybrid and PML proteins following treatment with ASC.

NB4 cells exposed to 3 mM ASC: after 8 h PML/RARA is degraded by 80%, and PML by 70% (A). In PR9 cells treated with ZnSO₄ for 2 h, PML/RARA is degraded after 2 h of treatment with 3 and 7 mM ASC (B). In NB4 cells treated with 3 mM ASC the proteasome inhibitor MG132, the autophagy inhibitor ClN4 and the caspase inhibitor Z-Vad were added. Only Z-Vad prevented ASC-induced degradation of PML and PML/RARA proteins in vitro (C). Using confocal microscopy, we observed reconstitution of PML NBs in NB4 cells after treatment with 3 mM ASC (D), and relocalization of DAXX in PML NBs (E). Colocalization of PML and DAXX was *p ≤ 0.05; ** ≤ 0.005 by unpaired t test. Quantification of number of nuclear bodies and colocalization, expressed in terms of overlap coefficient (R) was calculated on 30 randomly selected cells from different slides by using the WCIF ImageJ software (www.uhnresearch.ca/facilities/wcif/imagej/).