Ibrutinib induced cell apoptosis in GCB-DLBCL cell lines by caspase dependent pathway. (A and B) SU-DHL-16 and LY7 cells (1 × 105/ml) were treated with a concentration of 10 μM of ibrutinib for 6–72 hours and Annexin-V and PI staining apoptotic cells were analyzed by flow cytometry. Cells in early stage apoptosis were defined as Annexin-V positive and PI negative and cells in late stage apoptosis were defined as Annexin-V and PI dual positive. (C) SU-DHL-16 and OCI-LY7 cells (1 × 105/ml) were treated with10 μM of ibrutinib or DMSO for 24 hours. Then the total protein was prepared and the caspase 3 degradation and PARP cleavage were detected by Western Blot. β-actin was blotted as a loading control. Results were shown from one of three experiments and the representative results were shown in the figures.