Fig. 6: Activation of p53 mediates survivin depletion and sensitivity to BCL-XL inhibitors.

A LNCAP cells treated with nolatrexed (2 μM) for 48 h were immunoblotting for DNA damage response and p53 activation. Fold changes in P-RPA32 and p53 are quantified. B Time-course for DNA damage response and p53 induction in nolatrexed treated LNCaP cells. Fold changes in P-RPA32 and p53 are quantified. C Immunoblotting for DNA damage response and p53 targets in cells treated with raltitrexed and/or navitoclax. D Immunoblotting for p21 in LNCaP cells treated with thymidylate synthase inhibitors with and without thymidine rescue. E LNCaP cells were treated with 5-FU for 2 days followed by navitoclax for 6 hand caspase activation was assessed. Mean and SEM for 6 biological replicates are shown. Data at each 5-FU concentration were analyzed by unpaired t-test, *p < .05. Analysis by two-way ANOVA showed significant effect of 5-FU, p < 0.001. F Immunoblotting for MCL-1, p21, and survivin in LNCaP cells treated with 5-FU for 1–2 days. G LNCaP cells were treated with Nutlin-3a (MDM2 inhibitor) for 1–2 days. Left panel: LNCaP cells were treated with Nutlin-3a for 1–2 days followed by immunoblotting. Middle and left panels: LNCaP cells were treated for 24 h with Nutlin-3a followed by 6 h with navitoclax (middle panel) or AZ4320 (right panel) and assessed for apoptosis by Caspase Glo 3/7 assay. Mean and SEM for 3 biological replicates are shown. Data at each Nutlin-3 concentration were analyzed by unpaired t-test, *p < .05. Analysis by two-way ANOVA showed effects were significant (p = 0.006 for left panel and p = 0.0013 for right panel). H LNCaP and A549 cells were treated with TP53 or nontarget control siRNA. The effect of 5-FU on the p53 pathway and integrated stress response pathway was assessed with immunoblotting. I LNCaP cells were treated with p21 or nontarget control siRNA. The effect of 5-FU on survivin expression was then assessed with immunoblotting. Source data are provided as a Source Data file.