Combined exposure of SUDHL16 and OCI-LY10 cells to CFZ and vorinostat leads to a pronounced increase in caspase activation, mitochondrial damage, JNK activation, and DNA damage. SUDHL16 cells were treated with CFZ (3.0nM) with or without vorinostat (0.75μM) for 14 hours. (A) Cytosolic (S-100) fractions were obtained as described in “S-100 fractions,” and the expression of cytochrome C and apoptosis inducing factor (AIF) was monitored by Western blot. (B-E) Proteins from whole-cell lysates were prepared, and expression of the indicated proteins was determined by Western blotting after drug exposure identical to that described in panel A. Expression of acetylated Ku70 and acetylated Ku86 was determined by immunoprecipitation with Ku70 and Ku86 antibodies followed by Western blotting with acetyl-Lys primary antibody. (F) OCI-LY10 cells were treated with CFZ (7.0nM) with or without vorinostat (1.5μM) for 24 hours. Cells were lysed, sonicated, proteins denatured, and subjected to Western blot analysis using the indicated primary antibodies. Each lane was loaded with 20 μg of protein; blots were stripped and reprobed with antibodies directed against tubulin or actin to ensure equivalent loading and transfer. Results are representative of 3 separate experiments.