Bfl-1 is overexpressed in lymphomas and confers resistance to BH3 mimetics. (A) Reads per kilobase of transcript per million mapped reads (RPKM) for BCL2A1 across hematological cancer cell lines from the CCLE RNA-sequencing data set. (B) Violin plot for relative Bcl-2 family antiapoptotic protein levels across 52 lymphoma cell lines. Data were acquired from densitometric measurements of western blot band intensities from supplemental Figure 1A. (C) Correlation between BCL2A1 mRNA and Bfl-1 protein levels in a subset of 18 evaluated lymphoma cell lines. BCL2A1/Bfl-1 levels were normalized relative to the TMD8 cell line as 100%. Solid line indicates y = x-axis unity. (D) BCL2A1, MCL1, BCL2, BCL2L1, BCL2L2 mRNA abundance in lymphoma cell lines. (E) AZD5991 and venetoclax were assessed for caspase activation after 6 hours of drug incubation across the lymphoma cell line panel. Each dot represents individual cell lines that are either Bfl-1⁺ (red) or Bfl-1⁻ (blue). Solid line indicates the geometric mean 50% effective concentration (EC₅₀). (F) Cell viability of Bfl-1⁻ (blue) or Bfl-1⁺ (red) cell lines in response to a dose response of AZD5991 treated for 24 hours. (G-H) Lymphoma cell lines were treated with a fixed 0.33-µM dose of venetoclax combined with a dose response of AZD5991 for 6 hours before caspase activation was assessed. Each dot represents the caspase EC₅₀ (G) or area under the curve (AUC) parameters (H) of individual cell lines that are Bfl-1⁺ (red) or Bfl-1⁻ (blue). Solid line indicates the geometric mean EC₅₀ (G) or AUC (H). *P < .05; **P < .01; ****P < .0001.