A, The indicated cell lines were treated with DMSO, 200 nM osimertinib (Osim) alone, GDC0994 (GDC) alone, VRT752271 (VRT) alone or osimertinib combined with GDC or VRT for 16 h. The proteins of interest were detected with Western blotting. B-D, Bim-deficient cell lines derived from PC-9/AR, as confirmed with Western blotting (B), together with PC-9/AR parental cells were exposed to DMSO, 100 nM Osim, 2 μM GDC or their combination for 48 h. Annexin V-positive cells were evaluated with flow cytometry (C) and protein cleavage was detected with Western blotting (D). E and F, The given cell lines were exposed to DMSO, 100 nM Osim, 4 μM GDC or their combination for 48 h. Apoptosis was evaluated by Annexin V flow cytometry (E) and by detection of PARP cleavage with Western blotting (F). The data in C and F are means ± SDs of duplicate determinations. *** P < 0.001 compared with the effect of the combination in control cells.