BET inhibitors control the expression of ferroptosis-associated genes in DLBCL. (A) Heatmap of genes differentially expressed in DOHH2 cells treated with 0.25 μM JQ1 for 12 or 24 hours compared to the solvent control. Gene expression changes are depicted according to the color scale. (B) DOHH2 cells were treated with 0.25 μM JQ1 for 12 or 24 hours. Transcript levels of the indicated genes were quantified by qPCR. Expression in JQ1-treated cells was normalized to the respective solvent control. SDHA served as reference gene. (C) SLC7A11 mRNA levels of solvent- or JQ1-treated GCB-DLBCL cell lines were determined by qPCR. SDHA served as reference gene. (D) The indicated GCB-DLBCL cell lines were incubated with 0.25 μM JQ1 or I-BET151 for 48 hours. SLC7A11 protein levels were visualized by immunoblotting. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) served as loading control. (E) Reduced GSH was quantified in the indicated GCB-DLBCL cell lines upon treatment with solvent, JQ1 or I-BET151 for 24 hours. GSH concentrations were normalized to the respective solvent control. (F) DOHH2 cells were treated with 0.25 μM JQ1 or I-BET151 alone or in combination with different concentrations of DMF. GSH levels were quantified and normalized to the solvent control. (G) The GCB-DLBCL cell line DOHH2 and the ABC-DLBCL cell line U2932 were treated with 0.25 μM JQ1 alone or in combination with the indicated concentrations of DMF. GSH levels were quantified and normalized to the respective DMF-treated controls. Error bars correspond to the mean ± SD. Data are representative of at least 3 (B-C,E-F) or 2 (D,G) independent experiments. ∗P < .05; ∗∗P < .01; ∗∗∗P < .005. GSH, glutathione; mRNA, messenger RNA; n.s., not significant; qPCR, quantitative polymerase chain reaction.