Co-operative induction of apoptosis by pladienolide, torin1, etoposide or AC220 with JQ1.

(A) Time course of bcl-2 protein downregulation in response to JQ1 measured by flow cytometry. MFI = mean fluorescence intensity, corrected for isotype control. (B) Time course of delta priming to BAD-BH3 and MS1-BH3 measured by cytochrome C release after drug treatment and additional incubation with the indicated BH3 peptides. Values are corrected for Cytochrome C release with peptide only as described in the methods. (C) Cells were incubated with 250 nM JQ1 for 2 days. 10nM pladienolide B (PLB), 1 μM torin1, 10nM ABT-199 (199), 1 μM etoposide (ETO) or 10 nM AC220 were added for the final 4 hours. Cells were then fixed and processed for Cytochrome C release. Bright blue bar height = cytochrome C release with both agents in combination–sum of cytochrome C release with both agents individually). Fold excess additivism is shown on the figures and was calculated as a ratio of observed to expected values after corrections according to the Bliss algorithm (see methods). Asterisks indicate observed values significantly higher than expected values (P<0.05). (Mean+/- SD for n = 3).