Figure 2. Tenovin-6 has limited effects on PML-RAR.

-α stability and PML-NB formation. (A) PML-RAR-α accumulation was examined when NB4 cells were cultured in the presence of ATRA (1 µM) or tenovin-6 (3 µM) for the indicated time. 175 µg extracts were loaded in each lane. Note that longer incubation with tenovin-6 lowered PML-RAR-α accumulation, but some remained at 72 hours, whereas PML-RAR-α was rapidly degraded in ATRA-treated cells, and the protein had nearly disappeared at 72 hours. We obtained similar results in another, independent experiment. (B) PML-NB formation in tenovin-6 (3 µM)- or ATRA (1 µM)-treated or untreated NB4 cells after 120 hours of incubation was examined by immunofluorescence microscopy using anti-PML antibody. While ATRA treatment induced PML-NB formation, as reported previously [37], [38], tenovin-6 treatment did not show any effect on PML-NB formation.