Figure 4. Tenovin-6 induces granulocytic differentiation in APL cells via inhibition of SIRT2, but not of SIRT1.

(A) NB4 cells were treated with another sirtuin inhibitor, BML-266 (5 µM), for 3 days, and images from NBT reduction assays are presented. Positive cells in the NBT reduction assay were counted under the microscope as described in Figure 1F and are depicted in the graph. Error bars show mean ± SD (n = 3). **P<0.01. ***P<0.001. (B) Acetylated forms of SIRT1 and SIRT2 substrates p53 and α-tubulin, respectively, were examined after tenovin-6 (3 µM) or DMSO (vehicle) treatment for the indicated period. 42 µg extracts were loaded in each lane. Total tubulin and p53 levels were unchanged. β-Actin immunoblot analysis was performed to obtain a loading control. A single and double asterisk indicates acetylated and unacetylated α-tubulin, respectively.