Figure 3.

Pro-apoptotic effects of VPA are rapidly decreased by ATRA and inversely correlate with C/EBPɛ expression. (A) After stimulating the NB4 cells for 6 h with ATRA (1 μM), the medium was changed and cells were washed. Then the cells were exposed to VPA for 24 h or they were not further treated. NB4 cells treated for 24 h with ATRA were used as a control. Immunoblot analysis of NB4 whole-cell protein lysates was done to assess the levels of C/EBPɛ, acetylated histones H3 (acetyl-H3), cleaved caspase-3, and GAPDH as a loading control. (B) Whole-cell protein extracts were prepared from treated NB4 and NB4-R2 cells. Immunoblot was used to detect the protein expression of C/EBPɛ, cleaved caspase-3 (cl., cleaved form) which is the active form of the caspase, and α-tubulin as a loading control.