Fig. 3: PI3K/AKT pathway inhibition drives apoptosis when combined with MCL1 inhibition in LNCaP95 and C4-2 cell lines.

A FDA-approved drug screen (n = 166 drugs) in LNCaP95, C4-2, and PNT2 cells, in the presence and absence of AZD5991 (1 µM). FDA approved drugs used at 5 µM. Caspase 3/7 activity (6 h; Caspase-Glo 2D) and cell viability (24 h; CellTiter-Glo 2D) were assessed. The x-axis shows the effect of each FDA drug alone (FDA/DMSO), and the y-axis shows the added effect of combining AZD5991 with each drug (FDA + AZD5991/FDA). Experiment performed as a single biological replicate in technical singlets. PI3K inhibitors are highlighted in red. B Heatmaps showing the combined effect of AZD5991 with FDA drugs on caspase activation (6 h) and cell viability (24 h) in LNCaP95 and C4-2, normalised to the effect on the normal-like prostate cell line PNT2. Blue and red indicate increased or decreased caspase 3/7 activity or cell viability, respectively. C Zero Interaction Potency (ZIP) synergy scores comparing combinations of AZD5991 with PI3K inhibitors (copanlisib, buparlisib) versus AKT inhibitors (capivasertib, ipatasertib) in LNCaP95 cells. Data are mean ± SEM from three biological replicates (each with three technical replicates). One-way ANOVA with Tukey’s post-hoc test. D ZIP synergy surface plots for AZD5991 combined with PI3K (copanlisib, buparlisib; left) or AKT (capivasertib, ipatasertib; right) inhibitors in LNCaP95. Caspase 3/7 activity (6 h), cell viability (24 h), and protein expression of cleaved PARP, cleaved caspase 3, and phosphorylated AKT (Ser473) following treatment with DMSO, AZD5991 (1 µM), capivasertib (1 µM), ipatasertib (1 µM), or combinations in LNCaP95 (E) and C4-2 (F). Bars show mean ± SEM of three biological replicates (three technical replicates). Statistical comparisons performed using one-way ANOVA with Tukey’s post-hoc test. Asterisks indicate statistical significance between groups (***p < 0.001). Source data and exact p values are provided are provided as a Source Data file.