Constitutive IP3 signaling underlies the sensitivity of B-cell cancers to the Bcl-2/IP3 receptor disruptor BIRD-2

High IP3R2-expression levels are not sufficient per se to render cells sensitive to BIRD-2. a The IP3R2- and Bcl-2-protein levels present in cell lysates from SU-DHL-4 (40？μg), OCI-LY-1 (40？μg), and HepG2 (40？μg) cells and from microsomes extracted from primary hepatocytes (20？μg) were determined by western-blot analysis. The expression level of calnexin was used as a control for equal loading. b Representative dot plots from flow cytometry analysis measuring apoptosis by staining SU-DHL-4, OCI-LY-1, HepG2 cells and primary hepatocytes with Annexin V-FITC and 7-AAD. Cells were treated with vehicle or 10？μM BIRD-2 for 2？h. The dot plots are representative of 3 independent experiments. c, d Quantitative analysis of 3 independent experiments detecting apoptosis in Annexin V-FITC/7-AAD-stained cells treated with vehicle or 10？μM BIRD-2. Apoptotic cell death was measured 2？h (c) and 24？h (d) after BIRD-2 treatment. Data are represented as average？±？SEM (N？=？3). Statistically significant differences were determined with a Student’s t-test (paired, two-tailed, *P？<？0.05) (BIRD-2 versus vehicle