Fig. 4

Combined treatment of resistant lymphoma cells with BSK805 (and other targeted drugs) with copanlisib or duvelisib. a OCI-Ly1-copanlisib and HH-duvelisib resistant cells were treated with copanlisib (1 μM) or duvelisib (1 μM) in the presence or absence of BSK805 (100 and 300 nM) for 72 h. Cell viability was evaluated by trypan blue staining. b Apoptosis was detected using annexin V/propidium iodide staining. Caspase-3/7 enzymatic activity was measured using a luminometer. Data represent mean values ± SEM of three independent experiments. Each experiment was performed with triplicate samples. P-values were determined by one-way repeated-measures ANOVA. Triple asterisk indicates statistically significant difference at P ≤ 0.005, double asterisk significant at P ≤ 0.01. c Western blot analysis of STAT3, STAT5, AKT, MAPK, NF-κB, and p70S6K phosphorylation in resistant cells treated with copanlisib (0.3 and 1 μM) or duvelisib (1 μM) and BSK805 (100 and 300 nM). The bands on the Western blots were quantified via densitometry. d Responses to single agents and combined treatment regimens were evaluated by CCK-8 assay and isobologram analysis. Viability, estimated by CCK-8 assay, was determined in matrix block experiments. Interactions of copanlisib and U0126 or duvelisib and velcade were assessed by determining combination index (CI) values using CalcuSyn software (Biosoft, Ferguson, MO, USA), where CI values > 1, = 1 and < 1 signify antagonism, additivity and synergy, respectively