Pharmacological inhibition of p97 interferes with arsenic-induced degradation of PML and PML-RARA. NB4 cells were either untreated (UT) or treated with arsenic (As), CB-5083, or a combination of arsenic and CB-5083 for the times indicated. Cells were centrifuged onto coverslips, fixed and stained with antibodies to PML (green) and RARA (red), and DNA visualized by DAPI staining (blue).