Bortezomib synergizes with pp242 for enhanced antimyeloma effects. 8226 cells were incubated with increasing concentrations (shown in nM) of bortezomib ± pp242 for 48 or 72 hours. (A) Viable cell recovery was assessed after 72 hours and data are presented as percent of control where cultures without any drugs were arbitrarily made 100%. (B) Percent apoptosis (flow cytometry for activated caspase 3) is shown after 48 hours of incubation. Data are mean percent apoptosis ± SD (n = 3). (C) median effect/CI analysis is shown for 8226 cells treated for 48 hours with combinations of pp242 and bortezomib where apoptosis was assayed by annexin V staining. The ratio of concentrations of pp242:bortezomib was held constant at 10:1 for the purpose of median effect/CI method analysis with the pp242 concentration given under the horizontal axis. CI values < 1 indicate synergy. Vertical axis on the left represents fraction of cells affected (FA) and vertical axis on the right represents the CI values.