HDAC inhibitor treatment synergistically promotes cell death following ferroptosis induction. (A) Lipid peroxidation levels were assessed by measuring relative changes in fluorescence of unoxidized versus oxidized C11-BODIPY probe following treatment with DMSO (control), 2 nM FK228, 1 μM erastin 5 μM erastin (5 μM E), or a combination of 2 nM FK228 and 1 μM erastin (FK228 + E) for 48 h. Changes in relative amounts of oxidized probe were normalized relative to cell viability. (B) Cell viability was measured following treatment with DMSO (control), 2 nM FK228, 1 μM erastin (1 μM E) or 5 μM erastin (5 μM E), or a combination of 2 nM FK228 and 1 μM erastin (FK228 + E). Rescue experiments were performed by adding 10 μM Fer1 to the 5 μM erastin treated cells (5 μM E + Fer1) and the combination of 2 nM FK228 and 1 μM erastin treated cells (FK228 + E + Fer1). Superscripts denote statistical difference, p < 0.05. Treatments with a shared superscript are not statistically significant. Data are presented as mean ± SEM.