![PLX51107 and PLX2853 BETi invoke cell death via intrinsic apoptosis in Eμ-myc lymphomas. (A) PLX51107 (PLX5), PLX2853 (PLX2), JQ1, and OTX015 were administered to Eμ-myc lymphoma cell lines for 48 hours, and viability was assessed by annexin V/PI staining vs vehicle control (dimethyl sulfoxide [DMSO]). Points represent the mean of 12 wild-type (WT) cell lines, each performed in triplicate, normalized to control viability and expressed as percentage specific viability. (B) Data from panel A were used to calculate IC50s. Darker shaded symbols represent cell lines used for subsequent in vitro experimentation. Crossed circles denote the AH29 lymphoma cell line, triangles denote AF47, and squares denote Eµ# 4. (C) Eμ-myc lymphoma cell lines (n = 3), pretreated with 25 μM qVD or a DMSO vehicle control for 1 hour, were exposed to 1000 nM PLX5, 100 nM PLX2, or an additional vehicle control (Con) and viability assessed as in panel A. (D-E) WT, control (pMIH), or BCL-2/BCL-XL transduced Eμ-myc lymphoma cell lines treated with 1000 nM PLX5, 100 nM PLX2, or a DMSO vehicle control (Con) were assessed for viability (D) and changes in mitochondrial membrane potential (Δψm) (E) by annexin V/PI or DiOC6/PI staining, respectively. Points in panels C-E represent the mean of 3 independent experiments for each cell line, performed in triplicate. (F) Matched WT or BCL-2–transduced Eμ-myc lymphoma-bearing C57BL/6 were treated with (n = 7) 10 mg/kg PLX5, (n = 6) 5 mg/kg PLX2, or (n = 11) vehicle control, starting 4 days after engraftment and survival was assessed. Data are collated from 2 independent experiments using 2 different matched pairs of WT and BCL-2–transduced Eμ-myc lymphoma cell lines. Error bars represent standard error of the mean (SEM). Statistical analyses were performed using 1-way (B) or 2-way analysis of variance (ANOVA) (A and C-E) and P values adjusted using Tukey’s or Dunnett’s multiple comparisons tests. In panel A, asterisks represent comparisons of overall curves between different conditions. Survival analysis was performed using a log-rank test adjusted for multiple comparisons using the Holm-Sidak method. ****P < .00005, ***P < .0005, **P < .005, *P < .05. ns, nonsignificant.](https://ash.silverchair-cdn.com/ash/content_public/journal/bloodadvances/4/14/10.1182_bloodadvances.2020002231/2/advancesadv2020002231f1.png?Expires=1724949594&Signature=x8JWSAEbnG1p68TtwhBwEqVqLjuqsnpiHkF7wzWu0~YL-jQ-uo0S6kYmgScWp-ii6izM1bsFS1O-2Ox8NIHe784gWnq-IILUArSQg5mhboOVNaWQJgaTMxQLelDlDBsXhOHH~8B3OnUS5WpSXPtIThI0dDkFNp4xJS6fzz~x0aKp5pWwu2XSZNsVLZgvHotewth2KtZZ4wRk5kdwqsEY~aFr2XmWWIWH2WGfnHaZGJYvEiDQEK-15L0O-cdsT8VBY3PZCZ8YfBLYdnH-56BzJmIwfg41o~D13y8CskSjqCcvXmHjvMNq9a6GhYjhDNzioqUoRxyUl538sYNFB2VBUw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
PLX51107 and PLX2853 BETi invoke cell death via intrinsic apoptosis in Eμ-myc lymphomas. (A) PLX51107 (PLX5), PLX2853 (PLX2), JQ1, and OTX015 were administered to Eμ-myc lymphoma cell lines for 48 hours, and viability was assessed by annexin V/PI staining vs vehicle control (dimethyl sulfoxide [DMSO]). Points represent the mean of 12 wild-type (WT) cell lines, each performed in triplicate, normalized to control viability and expressed as percentage specific viability. (B) Data from panel A were used to calculate IC50s. Darker shaded symbols represent cell lines used for subsequent in vitro experimentation. Crossed circles denote the AH29 lymphoma cell line, triangles denote AF47, and squares denote Eµ# 4. (C) Eμ-myc lymphoma cell lines (n = 3), pretreated with 25 μM qVD or a DMSO vehicle control for 1 hour, were exposed to 1000 nM PLX5, 100 nM PLX2, or an additional vehicle control (Con) and viability assessed as in panel A. (D-E) WT, control (pMIH), or BCL-2/BCL-XL transduced Eμ-myc lymphoma cell lines treated with 1000 nM PLX5, 100 nM PLX2, or a DMSO vehicle control (Con) were assessed for viability (D) and changes in mitochondrial membrane potential (Δψm) (E) by annexin V/PI or DiOC6/PI staining, respectively. Points in panels C-E represent the mean of 3 independent experiments for each cell line, performed in triplicate. (F) Matched WT or BCL-2–transduced Eμ-myc lymphoma-bearing C57BL/6 were treated with (n = 7) 10 mg/kg PLX5, (n = 6) 5 mg/kg PLX2, or (n = 11) vehicle control, starting 4 days after engraftment and survival was assessed. Data are collated from 2 independent experiments using 2 different matched pairs of WT and BCL-2–transduced Eμ-myc lymphoma cell lines. Error bars represent standard error of the mean (SEM). Statistical analyses were performed using 1-way (B) or 2-way analysis of variance (ANOVA) (A and C-E) and P values adjusted using Tukey’s or Dunnett’s multiple comparisons tests. In panel A, asterisks represent comparisons of overall curves between different conditions. Survival analysis was performed using a log-rank test adjusted for multiple comparisons using the Holm-Sidak method. ****P < .00005, ***P < .0005, **P < .005, *P < .05. ns, nonsignificant.