BCL2 and cancer: First, basal single-channel IP3R activity was acquired in the presence of 2 μmol/L (Figure 1C) or 5 μmol/L [IP3] (Figure 1D), followed by the addition of 1 μmol/L ABT-199, a concentration sufficient for binding Bcl-2 in several cancer cell lines with a lethal dose 50 (LD50) of about 10 nmol/L [33, 44].